Indian J Pediatr 1989 ; 56 : 35-54
Teaching Technical Skills in Pediatrics Steven M. Selbst, M. Douglas Baker, Louis M. Bell, Kathy N. Shaw, Cynthia Briede, G. Anthony Woodward and Stephen Ludwig Departm on t of Podia trics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, U.S.A. Technical skills are an important and difficult part of managing a very sick or injured child. However, technical procedures are more often learned from experience than practice. This article reviews a variety of technical skills and procedures commonly performed in a pediatric emergency department. Each technical procedure can be practiced using live or artificial model for simulation.
The management of pediatric emergencies often involves the performance of a technical procedure or use of special equipment. If the procedures are properly and quickly performed in the Emergency Department (ED), the child has a much greater likelihood of surviving a serious illness or major trauma. Unfortunately, the training for such technical procedures is often lacking in medical schools. Moreover, once learned, these skills may fade unless there are frequent opportunities for practice. Thus, pediatricians and residents often learn the correct or successful method of doing a procedure by first performing the task unsuccessfully on one or several children. This trial by error method of learning is certainly not the best or the only way to Reprint requests : Dr. S.M. Selbst, Associate Director~ Division of General Pediatrics, Emergency Department, Tile Children's Hospital of Philadelphia, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104, U.S.A.
master common technical procedures in pediatrics. We have accumulated several methods to teach technical procedures to pediatricians and residents. The purpose of this article is to share a variety of techniques used to master technical skills. For instance, intravenous line placement and arterial puncture can be practiced using dye-filled plastic models that simulate ,arteries and peripheral or central veins. These models provide direct feedback when the vessels are cannulated. Commercially available models and even live kittens are useful to practice intubation skills. Moreover, fresh supermarket meat can be used to practice suturing techniques. Likewise, sections of newborn, umbilical cords can be frozen and thawed later so that umbilical catheterization can be practised. Furthermore, chicken bones can be used to practice the skills involved with intraosseous infusions. This article will discuss other technical procedures and special equipment such as airway management, the use of pneumatic
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TIlE INDIAN JOURNAL OF PEDIATR/CS
antishock trousers, and splinting and taping of orthopedic injuries. This article hopes to describe how to perform several important technical tasks. It will also convey a means of teaching such tasks to others. 1. V A S C U L A R A C C E S S : SELDINGER
TECHNIQUE During emergency resuscitation peripheral veins and scalp veins may be difficult to find and may allow only small catheters with inadequate rates of flow. Access to the central venous circulation is desirable to administer drugs and large amounts of fluid. The Scldinger technique is used for percutaneous access to the central circulation. Necessary equipment includes a flexible infusion catheter (Cook No. 10 or 11 which is equivalent to 20 or 18 gauge), a metal needle, 10 ml syringe, and a guidewire. The guidewire must have a diameter small enough to pass through the needle and it must be long enough to extend outside the catheter so it will not slide into the vessel. A J-tip guidewire will allow easy passage through tortuous vessels such as the extemal jugular and subclavian veins. The preferred sites of access include the femoral vein, external jugular vein, the subclavian vein and internal jugular vein. Performing the task : (i)Femoral vein approach : Palpate the femoral artery 1.5 cm below the inguinal ligament. It is midway between the anterior superior iliac crest and the symphysis pubis. Next, locate the femoral vein. It is just medial to the femoral artery. Cleanse the area with povidone-iodine solution. Then, under sterile conditions, use a needle attached to a
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syringe to puncture the skin over the femoral vein (at a 30 ~ angle), 1-2 finger breadths below the inguinal ligament. Withdraw on the syringe until blood flow is noted. Then disconnect the syringe and thread the guidewire into the needle and vein. Next, withdraw the metal needle, being sure the guidewire is visible at all times. Advance the infusion catheter over the guidewire and twist it under the skin, into the vein. This twisting motion will help to enlarge the cutaneous puncture site. Finally, withdraw the guidewire and attach the infusion set. Then tape or suture the catheter to the skin. An advantage of placing this catheter in the femoral vein is that cardiopulmonary resuscitation (CPR) does not need to be interrupted while this line is attempted. Some disadvantages include the potential for hematomas, infection, and catheter fragment embolism. 1,2
(ii) External jugular vein approach : Locate the external jugular vein with the patient supine and the head down. Cleanse the area with povidone-iodine solution. Again, under sterile conditions, aim the needle and syringe caudally, in the direction of the vein toward the ipsilateral shoulder. Pierce the skin 1/2 to 2/3 the distance between the angle of the jaw and the shoulder, to enter the vein. 2 Withdraw on the syringe until blood flow is noted. Then disconnect the syringe and thread the guidewire into the needle and vein. Next, withdraw the metal needle, being sure the guidewire is visible at all times. Advance the infusion catheter over the guidewire and twist it under the skin, into the vein. Finally, withdraw the guidewire ,and attach the infusion set. Then tape or suture the catheter to the skin.
SELBST ET AL : TEACHING TECttNICAL SKILLS
The advantages of using the external jugular vein for catheterization is that the vein is usually visible, and thus easily entered. Some disadvantages include the potential for hematomas and infection at the site. Also, an apical pneumothorax can result. Moreover, this site may be difficult to access unless the airway i~ stabilized since the neck must be rotated to locate the external jugular vein. Finally, an additional person trying to place the line at the neck area may interfere with CPR. (iii) Subclavian vein approach : Place the child in Trendelcnburg position with a towel roll under the back to hyprextend the back. Cleanse the neck and upper chest with povidone-iodine solution. Then, under sterile conditions use a blade to puncture the entry site at the depression bordered by the deltoid and pectoralis major muscles, under the distal 1/3 of the clavicle.2 Next, insert the needle directed toward the junction of the first rib and clavicle (sternal notch), withdrawing on the syringe as you go. Withdraw on the syringe until blood flow is noted. Disconnect the syringe and thread the guidewire into the needle and vein. Withdraw the metal needle, being sure the guidewire is visible at all times. Advance the infusion catheter over the guidewire and twist it under the skin, into the vein. Finally, withdraw the guidewire and attach the infusion set. Finally tape or suture the catheter to the skin. A chest x-ray should be obtained to confirm the position of the catheter tip and to look for complications, i.e., pneumothorax, hemothorax. Use of the subclavian vein has the advantage of allowing more subsequent neck
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movement than keeping a line in the jugular vein. 1 However, the disadvantages include interference with CPR during placement, and possible pneumothorax, hemothorax, or hydrothorax. The complication rate is high with placement of this line and it should be performed by an experienced physician. Complications can be reduced if the left chest is avoided, since the dome of the pleura is higher on this side and the thoracic duct is in the left chest. (iv) The central approach to internal jugular vein catheterization : Locate the triangle formed by the two heads of the sternocleidomastoid muscle and the clavicle. Use fingers to retract the carotid artery medially. Then, insert the needle attached to a syringe at the apex of the triangle noted above. Direct the needle caudally and laterally toward the ipsilateral breast nipple at a 450-60 ~ angle. I Withdraw on the syringe until blood flow is noted. Disconnect the syringe and thread the guidewire into the needle and vein. Next, withdraw the metal needle, being sure the guidewire is visible at all times. Advance the infusion catheter over the guidewire and twist it under the skin, into the vein. Finally, withdraw the guidewire and attach the infusion set. Then tape or suture the catheter to the skin. Obtain a chest x-ray to verify the position of the catheter and to look for complications. The advantages of this approach is that it offers rapid access to the central circulation. One disadvantage includes into, fcrence with CPR during placemem ,~l tt~c line. Also, hcmothorax, pneumodlt~rax, hydrothorax are likely as this is a difficult procedure to perform. Again, these complications can be
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reduced avoided.
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somewhat if the left chest is
perform the procedure : 1. antiseptic solution (povidone-iodine), gauze pads 2. sterile gown, gloves, drapes, mask 3. hemostats (4), scissors, forceps 4. scalpel handle ; #11 or #15 blade 5. 3.0 silk suture on straight or curved needle 6. umbilical tape (optional) 7. 10 ml syringe filled with normal saline 8. 3-way stopcock 9. umbilical catheter - 3 1/2 or 5 French 10. infusion solution containing heparin (lunit/ml) To begin the procedure restrain the infant supine in a frogleg position. The infant should be kept under a radiant warmer with continuous respiratory and cardiac monitoring throughout the procedure. Determine the appropriate length of catheter to insert by taking 60% of the distance measured from the infant's umbilicus to shoulder. The procedure should be done in as sterile a manner as possible with gown, gloves and mask. Attach the catheter to the stopcock and syringe. Flush it, leaving it filled with fluid, assuring that there are no air bubbles. Mark on the catheter the point determined to be the appropriate distance for insertion and replace it on the tray. Prep the umbilical area by lifting the umbilical cord with a forceps. (If possible have an assistant do this). Scrub the proximal end of the cord and the abdomen with the povidone-iodine solution. Place sterile drapes over the abdomen. While holding the cord up, place a purse string suture around the ba.~c tfl the cord (not on the skin) but leave the knot untied and the ends long. Umbilical tape can be tied around the cord in lieu of sutures.
Teaching~and practising the technique : The Seldinger technique for vascular access can be practised with the use of commercial models of the arm and neck made by Medical Plastics Laboratory, Inc. (P.O. Box 38, Gatesville, Texas, 76528 USA). The models are distributed by Armstrong Industries, Inc. (3384 Commercial Ave., P.O. Box 7, Northbrook, IL, 60062, USA). These models can be filled with red dye so that successful cannulation gives immediate feedback. Cook, Inc (P.O. Box 489, Bloomington, IN, USA, 47402), manufacture kits with necessary equipment (each includes a flexible ccntral venous pressure straight and J-tip catheter, guidewircs, and a needle.) These come in a variety of lengths and diameters, but 3.0 French or 4.0 French are best for children. 2. UMBILICAL ARTERY CATIIETERIZATION Umbilical artcry catheterization is indicated when vascular access is needed emergently in a newborn infant and attempts at peripheral access have failed. The procedure is relatively simple but complications can occur. Hemorrhage can result from catheter dislodgement or trauma during insertion. Infection and thrombosis may result if the catheter remains in place for a long time, or in a position that inhibits flow to the renal arteries or lower extremities. Air embolization can occur if care is not taken during insertion of the catheter. Performing the task : The following equipment is needed to
SEI~BSTET AL : TEACttlNGTECHNICALSKILLS
While holding traction on the distal end of the umbilical cord, sever the cord approximately 1.5 cm above the abdominal wall. Place the hemostat with the cut end of the cord out of the sterile field. Usually there is little bleeding which can be stopped with gentle pressure. If bleeding persists, the purse string can be tightened. Locate tile umbilical vessels. ~here would be one thin walled vein and two thick walled arteries. If the arteries are tortuous at that level, cut the cord closer to the abdominal wall to facilitate cannulation. Attach two clamps to opposite sides of the umbilicus. Grasp the fibrous portion of the cord, and evert the clamps to expose and immobilize the cord. Use the small curved forceps to enter the lumen of the artery. Gently dilate the artery repeatedly until the lumen is larger than the diameter of the catheter. To insert the catheter hold the artery open with the forceps. Grasp the distal end of the catheter near the tip and insert it between the prongs of the forceps. Pass the catheter using constant gentle pressure to overcome resistance at the skin and the site where the artery turns. Blood should flow freely back into the catheter once the iliac artery is rcached. Advance the catheter as far as the mark made at the outset. Confirm blood flow by drawing back on the syringe. Turn the stopcock off to the infant. Tighten and knot the purse sting, using the ends of the purse string suture. Tie a knot around the catheter approximately 5 cm from the skin to hold it in place. Tape the catheter to the abdominal wall. An abdominal x-ray will confirm the position of the tip of the catheter which should be between the third and fourth lumbar vertebrae.
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Teaching and practising the technique To demonstrate the procedure, and allow students to practise, collect pieces of umbilical cords from the obstetric department. The cords can be refrigerated in saline for 48 hours prior to use. Then use styrofoam trays or cardboard boxes covered with plastic to support the umbilical cords and simulate the abdominal wall. Cut a hole in the middle of the tray. Pass one end of an 8 cm length of cord through the tray and attach a clamp to the other end underneath the tray to hold it in place. Cannulation of both ,arteries and vein can be done on the cords set up in this manner~ although the catheter can only be passed as far as the clamp. For multiple demonstrations, use longer lengths of cord, allowing about 4 cm of it to show above the tray. The used portion can be cut off and discarded and the unused portion advanced above the tray so that each student has a fresh piece of umbilical cord on which to practise.
3. INTRAOSSEOUS INFUSIONS Intravenous access can be extremely difficult particularly in the scenario of shock or cardiac ,arrest in the small child. Intraosseous infusions of blood, glucose and saline solutions is technically easy to accomplish. This technique was described more than 50 years ago3,4,5 and became popular in the 1940's. With the development of plastic catheters in the late 1950 and 60's and improved techniques for placement, intraosseous infusion of I]uids was abandoned. However, rc~cw~ interest in perfecting methods of cardiopulmonary resuscitation, especially in children, has led to the rediscovery of the technique of intraosseous infusions.
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TIlE hNrDIANJOURNAL OF PEDIATRICS
Intraosseous infusion is a practical alternative for vascular access in the infant or child with circulatory collapse or cardiac arrest in whom other forms of vascular access are difficult. All types of fluids (including saline or blood to correct shock), and medications (atropine, dopamine, epinephrine, diazcpam, ~uecinylcholine) may be used in the emergency situation. 4 Intraosseous infusion should only be used until venous access is obtained. The medullary cavity of the tibia, a spongy network of venous sinusoids, drains via the emissary veins into the poplite,'fl vein and, finally, directly to the systemic venous circulation. Because the medullary vessels in the tibia are supported by a bony matrix, they do not collapse in patients with shock or cardiac arrest. Furthermore, fluids injected into the medullary cavity are distributed into the central circulation immediately. Tocantins5 showed that dye injected via the intraosseous route into the tibia of a rabbit appears in the right ventricle in 10 seconds. In addition, pH correction with intraosseous infusions using an experimental model for cardiopulmonary resuscitation was as good as using a central intravenous (IV) catheter and much better than the peripheral IV routefi The most immediate complication of intraosseous infusion is extravasation of fluid into the subcutaneous tissue. This is a problem when either the medullary cavity is not penetrated, the needle is accidentally forced into and through the opposite side of the bone, or the bone is fractured. Therefore, intraosseous infusion is not recommended in fractured bone or bones that have holes in the Cortex from previous unsuccessful I attempts. While the potential for infection
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(cellulitis or osteomyelitis) is a logical concern, the incidence is very low. In a review of more than 4,000 reported cases, osteomyelitis occurred in only 0.6%. 8 Nevertheless, areas of cellulitis or bums should be avoided as sites for insertion. For similar reasons, intraosseous infusion is contraindicated in osteogenesis imperfecta and osteopetrosis. Finally, damage to the epiphyseal plate is another theoretical concern, but no reported cases exist. It is for this reason that the needle should be inserted either perpendicular to the bone or pointing away from the epiphyseal plate. Performing the task : Following proper skin preparation and using aseptic technique, insertion of a needle with a styler into the medullary cavity of the proximal tibia or distal tibia is easily accomplished. Local anesthesia should be used for the awake patient. In children less than 18 months of age, a 18 gauge spinal needle can be used. In older children, a 13 to 16 gauge bone marrow needle is best. Commercially produced intraosseous needles are available from Cook Critical Care, Bloomington, Indiana that have a short shaft and easy grip handles. The proximal tibia is the most frequently used site until 5 years of age. After this age the cortex is infiltrated with fat cells making fluid administration more difficult. Placement of the needle is in the flat medial surface of the tibia 1-2 cm below the tibial tuberosity. The needle after penetration of the skin is directed perpendicular to the b, my ~haft. Firm but controlled pressure is alJplicd with a to and fro rotary motion until the needle passes through the cortex of the bone into the
SELBST ET AL : TEACIIING TECHNICAL SKILLS
marrow, then a release of resistance is appreciated. This is rarely more than 1 cm in the infant or child. Care should be taken when holding the limb, that the physician's fingers are not placed opposite the entry to avoid self impalement. After insertion, the stylet is removed and the position of the needle can be confirmed by attaching a syringe to the needle and aspirating blood or marrow. However, in a significant number of patients no marrow can be aspirated. In these cases, infuse some fluid and watch for cxtravasation of fluid and swelling of the subcutaneous tissue. One of the most common mistakes is to advance the needle through into the opposite side of the bone, in this situation the infusate will not flow and the needle may need to be pulled back slightly.9 In children more than 5 years of age (including adults) the distal tibia should be used with placement of the needle into the medial distal tibia just proximal to the medial malleolus. Practising and teaching the technique : This technique can be effectively taught to physicians and medical students using a variety of animal models. The authors have practiced successfully with the proximal tibia of the chicken (drumstick). Minimal preparation is needed, and following needle insertion into the medullary cavity, a syringe with a water colored dye can be injected into the needle in situ to demonstrate the dye flowing from the central veins which drain the area. This is an impressive demonstration of how quickly the intraosseous infusate flows into the central venous circulation. Other models include 6 week old kittens, and puppies which we have also found to provide a realistic simulation of the technique.
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Experimentation with other animals which are avaiIable in your area should leacl to discovery of an adequate model, which can be used to teach this life saving technique. 4. ARTERIAL PUNCTURE Most critically ill children require an arterial puncture to obtain a sample for blood gas determination. This procedure is useful whenever hypoxia or respiratory failure is suspected. Blood can be obtained from a variety of sites including the radial, brachial, dorsalis pedis and femoral arteries. We most commonly use the radial artery site as this is perhaps the safest. We rarely use the femoral site. Complications from arterial puncture include hematoma formation, ischemia of the extremity distal to the site of puncture, and arterial spasm. In rare cases, an arteriovenous fistula or septic arthritis may result from this procedure. Performing the task : The selected site for puncture should be cleaned with alcohol or povidone-iodine solution, which is then removed with 70% alcohol. A 1 or 3 cc syringe should be coated with heparin solution. This solution should also be flushed through a straight needle, or more commonly, a 25 gauge, 3 cm butterfly needle. For radial artery puncture, the child's arm should be held in supination just proximal to the wrist. The hand should be hypcrextended about 20~ to 30 ~ The arterial pulse should be palpated between the tips of the second and third fingers of the technician. The skin is then punctured at a 60 ~ angle between the palpating fingers. When the artery is punctured a pulsatile flow of blood will enter the needle and syringe allowing the arterial
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THE INDIAN JOURNAL OF PEDIATRICS
blood to be collected. If the initial attempt is unsuccessful, re-enter the artery from a slightly different angle, move medially or laterally. Careful arterial palpation should always be the guide. The needle is then quickly removed and pressure with gauze is applied to the puncture site for at least 5 minutes. Air bubbles should be removed from the blood sample and then the syringe is capped and placed on ice for transport to the laboratory. Practising and teaching the technique : Medical Plastics Laboratory, Inc. manufactures a model called "Baby Arti" for practising arterial puncture. Turning a hand crank produces pulsation at the wrist of the modcl simulating radial artery flow. The model can be filled with red dye so that puncture of the simulated vessel gives immediate feedback of the dye. 5. AIRWAY MANAGEMENT The first priority in basic or advanced life support is evaluation and treatment of the ,airway. Performing the task :
In the initial assessment, one should ; 1) look at the patient for signs of agitation or obtundation which may suggest hypoxia, hypercarbia, or airway obstruction and, specifically, at the chest and abdominal wall for signs of breathing effort ; 2) listen for the sound of air movement or abnormal sounds such as stridor, snoring, or gurgling ; and 3) fecl for evidence of air movement. Airway obstruction is common in the critically ill infant or child. The air passage may be easily obstructed by mucous, blood, vomitus, or, in an unconscious victim, the
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tongue and mandibular block of tissue. Various maneuvers and devices can be used to remove this occluding mandibular block of tissue from the airway. Non-invasive maneuvers to relieve airway obstruction include the head flit, chinlift, or jaw thrust : (1) Head tilt. A hand is placed on the forehead and the head is tilted gently back into a sniffing or neutral position in infants, and slightly further back in children. The head should not be tilted if neck injury is suspected. (2) Chin - lift. The fingers of one hand are placed under the mandible, which is gently lifted upward to bring the chin and its attached structures away from the airway. The thumb of the same hand lightly depresses the lower lip to open the mouth. The fingers should not push on tile soft tissue of the neck since this could cause obstruction of the airway. The chin-lift maneuvers will not hyperextend the neck and this can be used for the trauma victim with possible cervical spine injury. 1~ (3) Jaw thrust. Two or three fingers of each hand are placed under the angle of the lower jaw on both sides, displacing the mandible forward. This is the method of choice when neck injury is suspected. 11 Several adjuncts are available to help alleviate the obstruction. One of these adjuncts is suction. Rigid suction devices (tonsil suction tip) are useful for removing thick oroharyngeal secretions and blood. If the patient is apneic, suction should be limited to ten seconds and then ventilation and oxygenation must be resumed.!1
SELBSTET AL : TEACIIINGTECIINICALSKILLS
Another adjunct is the oropharyngeal airway. The proper size oropharyngeal airway is estimated by placing the airway against the patient's face. It should extend from the center of the patient's mouth to the the ,angle of the jaw. The oral airway is inserted in the mouth behind the tongue. A tongue blade is used to depress the tongue when inserting the airway to prevent the tongue from being pushed backward and blocking, rather than clearing, the airway. An oral airway should not be used for a conscious child since vomiting and aspiration or laryngospasm may be induced.2 In addition, nasopharyngeal airways can help relieve airway obstruction. The nasoph~uyngeal airway to be used should be as long as the distance from the child's nares to the tragus of the car. It should be lubricated and inserted into the nostril and directed posteriorly and towards the ear. These are better tolerated in the conscious patient. Adenoidal hypertrophy and bleeding diatheses are relative contraindications to their use. 12 Various oxygen delivery devices 13 are available for the child who is ventilating, but hypoxic. For instance, a nasal eannula is a simple, lightweight, well tolerated device for delivering oxygen in the sponteneously breathing older child. A maximum flow of 4-6 litres/min of 100% oxygen delivers approximately 30-40% oxygen. Also, an oxygen hood is used to provide a controlled environment of oxygen, humidity and temperature for infants. It can deliver up to 80--90% oxygen. The oxygen tent impedes access to, and evaluation of, the patient and is not used in emergency situations. However, a simple oxygen mask is lightweight, inexpensive and delivers a moderate concentration of oxygen. Side ports allow the child to breathe if the oxygen flow
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is disrupted. It may be a hazard if the patient vomits. Likewise, partial rebreathing mask is a combined face mask and reservoir bag which allows higher oxygen delivery (35-60% O2) than a simple mask. When the flow rate into the bag is greater than the patient's minute ventilation, and is adjusted so that the bag does not collapse during inhalation, there is negligible CO 2 rebreathing. Finally, a non-rebreathing mask has a non-rebreathing valve ie mask and a reservoir bag, which allows oxygen concentrations up to 100%. It requires a tight fit for proper function. Bag-valve devices are used to assist ventilation. The masks used with bag-valve devices should be transparent to permit prompt recognition of regurgitation. Also, masks with cushioned rims provide a tight face seal. Hand squeezed, self-inflating resuscitators are the most commonly used resuscitators since they are easy for the inexperienced operator to use. They should not have pressure limiting pop-off valves since the pressure required for adequate ventilation may exceed the pre-set pressure where the pop-off mechanism is activated. They require an oxygen reservoir adaption to deliver high oxygen concentrations. Anesthesia bags, unlike the self-inflating resuscitators, depend on adequate gas flow to maintain a compressible unit which propels gas towards the patient. Considerable experience is needed to use them effectively since one must be able to judge adequate flow rates to prevent over or underfilling of the bag. If the bag deflates due to a loose fit of the mask on the child's face, one must wait for the reservoir to refill. However, if used correctly, one can finely regulate the pressure and oxygen concentration delivered
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to the patient when this is used with an oxygen blender. Practising and teaching the technique : These techniques can be easily practised with mannequin models which allow placement of the oropharyngeal and nasopharyngeal airways. The user should be able to see the lungs inflate if the airway is positioned properly and the mask devices are used correctly. The models are available through Armstrong Industries, Inc. 6. OROTRACItEAL INTUBATION After the airway is stablized, intubation of the critically ill or injured child may be necessary. All the necessary equipment and personnel should be made available before attempting to intubate the airway. Performing the task : The necessary equipment includes a bag and mask device for preoxygenation or assisted ventilation should the intubation attempt fail. Certainly, an adequate suction source should be available, as well as a variety of endotracheal tubes with proper connectors to fit the airway tubing. The proper endotrachcal tube size for a child can be approximated by adding 16 to the child's age (in years) and dividing by 4. For exmple, a 4-year-old child needs a 5 mm diameter endotracheal tube. age (4) + 16 -5 4 Since this is only an approximation, it is best to have tubes available that are slightly smaller and larger. 14 In general, uncurled tubes ,are used when the diameter is less than 6 mm. This is because there is a natural narrowing of a child's airway at the
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cricoid cartilage and a cuffed tube is not needed.11
It is helpful to use a teflon coated stylet inside the endotracheal tube since the small endotracheal tubes are difficult to guide without such a stylet. However, to avoid laryngeal trauma, the stylet should be fixed 1 such that it ends 1 cm proximal to the end of the endotracheal tube. The laryngoscope should be checked to see that the light provided is adequate. Extra bulbs and batteries should be available nearby. Also, a variety of laryngoscope blades should be available. In general, a premature infant requires a size 0 Miller (straight) blade. A term newborn, up to age 3 years can be managed with a size 1, Miller (straight) blade. A child age 3 years to 12 years needs a size 2 Millet (straight) or Macintosh (curved) blade. Older children are usually managed with a size 3 Macintosh (curved) blade. To attempt the intubation first extend the child's head into the "sniffing position".The child's head should be lifted off the bed slightly, with a towel roll or placement of an assistant's hand under the occiput. It is important not to over extend the neck as this will displace the larynx more anteriorly and make intubation difficult. Such hyper-extension of the neck may cause collapse of the trachea as the young trachea does not have firm cartilagenous support34 Next, preoxygenate the patient with 100% oxygen for at least one minute. Of course, careful monitoring of cardiac function is important. The person attempting the intubation should open the child's mouth with his/her right thumb and index finger, and pull the mandible open and forward.
SELBST ET AL : TEACItlNG TECHNICAL SKILLS
The laryngoscope handle should be held in the left hand and the blade should be inserted in the right corner of the patient's mouth. The blade is then pulled in the center of the mouth while the patient's tongue is depressed. The blade should be advanced into the hypopharynx with direct visualization. The mandibular block of tissue is elevated by exerting force along the axis ot~ the laryngoscope handle in an upward, outward direction. Avoid trauma to the teeth and gums ; deciduous teeth are easily dislodged. Moreover, pressure on the gums of infants may permanently damage underlying tooth buds. The blade should then be slowly withdrawn until the larynx is seen. It may be helpful to have an assistant apply gentle pressure on the cricoid cartilage to improve visualization of the vocal cords. The infant larynx is more anterior than that of an adult. 15 The endotracheal tube is advanced into the pharynx from the right side of the mouth so that vision is not obstructed by the tube. It is placed 2 to 3 cm into the trachea. Before the tube is securely' taped, the chest wall should be examined for symmetric motion and the lungs should be auscultated for equal breath sounds. If only the right chest is being ventilated, it is possible that the right mainstem bronchus has been intubated and the tube should be withdrawn slightly. Avoid extension and flexion of the child's head after intubation. Extension may lead to extubation, and flexion could push the endotracheal tube into the right mainstem bronchus. A chest x-ray should be obtained to confirm the position of the endotracheal tube. It should be assumed that an awake patient may have a full stomach, and thus medication is required before intubation to
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prevent aspiration of gastric contents. The child should receive atropine 0.01 mg/kg intravenously to block vagal reflexes. Then, after preoxygenation with 100% oxygen, thiopental 4 mg/kg is given intravenously. This dose is reduced in hypovolemic or frail patients. Intravenous succinylcholine (2mg/kg) is then given immediately after thiopental. Succinylcholine is contraindicated if the patient has a severe burn, major muscle trauma, or head trauma. Pancuronium should be used instead. 16
Practising and teaching the technique : Intubation skills are easily lost as the opportunity for use is, fortunately, rare in pediatrics. The technique of intubation can be practised using commercially available models of pediatric and adult heads. These are distributed by Armstrong Industries, Inc. The technique can also be practised using live kittens, t7 The kittens should be about 8 weeks old. They should be medicated with atropine (0.08 mg S.C.), to reduce oral secretions, and ketamine HCL 20 mg IM. Repeat doses of ketamine may be needed if the kitten appears active. With an assistant holding the kitten's legs, the intubation procedure will very much resemble that of a newborn infant (premature). Usually, an endotracheal tube diameter of 2.5 mm will be the proper size for use. The kittens tolerate this procedure well, with transient hoarseness and minor pharyngeal trauma as the only complications. This can be minimized by limiting the number of intubations per kitten. 7. PNEUMATIC ANTISHOCK GARMENT The pneumatic antishock garment is a useful
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TtlE INDIAN JOURNAL OF PEDIATRICS
device for management of a hypotensive child. This device became popular during the Vietnam War and was initially called M.A,S.T. or Military Anti Shock Trousers. Their use in prehospital and E.D. settings became more common in the 1970's. 18 The pneumatic antishock ~arments are now available in a small size for toddlers age 2-5 years, a larger size for children age 6-12 years and a large size for teenagers and adults. The device is not useful for young infants. Pediatric experience with these trousers is limited.19-2t They should not take the place of adequate fluid resuscitation. Pneumatic antishock garments (PAS) should be used when a child is in shock; especially when attempts to start an intravenous line are unsuccessful or when fluid replacement fails to reverse the child's hypotension. The device is thus especially useful when a child suffers from massive hemorrhage. However, it is also useful when a child is hypovolemic for any reason i.e., septic shock, toxic shock syndrome, or even anaphylaxis.22 The suit can also be used to stabilize pelvic or femur fractures.t9, 21 Some have suggested that the PAS garment is not better then good fluid resuscitation and rapid transport of the patient to a trauma center.23 However, with pediatric patients, intravenous access is especially difficult, and few trauma centers care for children. Thus, the PAS garment may be even more important for the resuscitation of children. The pneumatic antishock garment will cause an increase in blood pressure partly by increasing venous return to the heart. However, when the trousers are inflated they primarily act to increase blood pressure by increasing peripheral vascular resistance in
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the lower part of the body.20,24 The pneumatic antishock garment is generally used in life-threatening situations, so that problems encountered seem minor compared to the predisposing condition. However, an anterior tibial compartment syndrome is possible if intravenous fluids are infused distal to the leg compartment of the garment.20 Also, skin necrosis at the sites of bony prominences can occur. However, these problems can be minimized if inflating pressures are limited to that needed to achieve an adequate rise in blood pressure, and if the trousers are not used for excessive periods of time. If possible, avoid infusion of fluids at the ankles or feet if the leg compartment is inflated.2o The use of pneumatic antishock trousers is absolutely contraindicated in patients with pulmonary edema or myocardial dysfunction. This is because the pulmonary wedge pressure is increased when the garment is inflated and further decompensation is possible in patients with the above problems. 25 The garment should be used with caution when a severe head injury is present as it may cause increased intracranial pressure. 25 It may also worsen the child's condition when intrathoracic hemorrhage or rupture of the diaphragm is present, x5 Finally, the abdominal compartment should not be inflated if the patient is pregnant. Performingthe task : When a patient in shock presents, or is expected to arrive in the E.D., the trousers should be placed on the stretcher with all three components (two legs, abdominal section) open flat. The stopcock valves on the leg compartments should be opened. The child is placed on top of the suit. The patient's bladder and stomach should be
SELBST ET AL : TEACIIING TECttNrICAL SKILLS
quickly decompressed if possible. Next, the leg and abdominal sections of the garment should be wrapped around the patient with the Velcro straps fitting together. Then, with the hand pump (for toddler suit) or foot pump (for larger suits), the suit is inflated. First one leg is inflated, then the other if the patient's blood pressure or perfusion does not improve. The abdominal section of the suit should be inflated if there is no change in the child's condition after inflation of the legs. Higher inflation pressures can be used if the blood pressure does not improve. In general, the suit is inflated until the vclcro material begins to stretch and "crackle". When the desired pressures have been achieved, all stopcocks on the suit should be closed. The child, of course, needs to be carefully monitored. Bladder catheterization is possible without altering the pneumatic antishock garment. Once the pneumatic antishock garment has been placed into use, it should not be deflated until the child is stable. This is preferably done in the operating room or intensive care unit. The deflation should never be done quickly. Instead, the abdominal compartment is slowly deflated, and then one leg section at a time is deflated by opening the stopcock. The deflation of this suit should stop if the blood pressure falls by more than 5 mm Hg, and intravcnous fluid should be given quickly to restore the blood pressure. 25
Practising and teaching the technique : The use of PAS garments can be practised using a variety of mannequins made by Laerdal, distributed through Armstrong Industries, Inc.
47
8. SPLINTING AND CRUTCH INSTRUCTIONS The aim of splinting is to maintain the position to prevent further injury and minimize pain.
Performing the task : Children often present with fractured clavicles which can be splinted in an emergency room setting. A "figure of eight harness" should be properly fitted and used correctly. The correct harness size can be determined by trial and error with different splints or by using Table 1 as a guide. The harness is placed around the shoulders with soft padding against the skin and fastened posteriorly. The goal of the splint is to keep the patient's shoulders straight to immobilize the clavicle and minimize pain. The harness should be left in place for approximately three weeks and may be removed for bathing. It should be left in place while slecping. If the distal 1/3 of the clavicle is fractured ; a simple arm sling is ~ more appropriate than a figure of eight harness. 2 Table 1. Figure-of-eight hamess sizes
Size
Chest circumference
(cm) Extra extra small Extra small Small Medium Medium long
<20 20-25 25-30 30-35 33-39
Non-displaced extremity fractures can
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TItE INDIAN JOURNAL OF PEDIATRICS
also be splinted in an emergency room setting, while awaiting definitive care from an orthopedic surgeon. Plaster is a versatile splinting medium, as it allows a splint to be moulded to the individual patient. Premoulded splints may also be used if available and correctly sized. Plaster splints may be constructed from plaster rolls, such as those used in casting or from prelayered and prepadded ready made splints. Fiberglass splinting material may also be used, though care must be taken to use cold water in their preparation to avoid burning the patient as the splint hardens. The necessary strength and thickness of the plaster splint is determined by the job it needs to do. A wrist or arm splint need not be as heavy or strong as a posterior leg splint. Prelayered splints already include padding to protect the skin from abrasion, whereas padding must be added to those splints that are made from plaster rolls. The simplest method of splinting is to apply a velar (palmar) splint moulded to the shape of the involved extremity and held firmly, but not too tightly in place by an elastic bandage. The elastic bandage should also be applied from distal to proximal to avoid trapping blood beyond the elastic bandage. Distal circulation should always be assessed after the application of such a splint. A nondisplaced, or minimally displaced fracture immobilized in such a manner will maintain alignment and not be further injured while awaiting orthopedic consultation. To splint a wrist fracture that is not severely displaced, a velar splint is used that extends from the proximal forearm to the distal palmar crease (metacarpal phalangeal joints). The wrist should be in 20--30~ of extension and the metacarpal phalangeal joints should have full flexion capability. A
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similar splint may be used for finger fractures. An extension that encompasses the length of the injured finger is added to the previously described velar wrist splint. The involved finger can be buddy taped to an adjacent non-injured finger prior to placing it in the splint. It is important to place gauze between any finger that are buddy taped to prevent interdigital maceration. Any splinting to the hand as above should be a temporary measure until a definitive splint or cast can be applied by an orthopedic surgeon. Incorrect and prolonged splinting can lead to contractures and loss of function of the injured extremity. If an open wound is involved, splinting is also helpful to avoid further injury and allow faster healing of the injured area. Before the splint is applied, all constrictive clothing and jewellery should be removed. A non-adherent dressing should be placed over the wound and covered with a layer of damp sterile gauze. This will enhance fluid drainage from the wound to the overlying dressing. Dry gauze should then be placed over the dampened gauze and the entire dressing held in place by an elastic type bandage. Care must be taken to avoid vascular compromise by this circumferential bandage. A velar splint should then be applied as mentioned above. Velar splints are also quite helpful in lower extremity injuries. Fractured or sprained ankles, and tibia/fibula injuries can be adequately immobilized by a posterior splinting that extends from the proximal tibia to the metatarsal phalangeal joints. 26 This splint should be heavier than the arm splints as it may be subjected to more stress than the arm splints. A patient with a posterior leg splint will need to use crutches to ambulate.
SELBST ET AL : TEACIThNG TECHNICAL SKILLS
Before the use of crutches is explained to the patient and his family, medical personnel must be certain that the crutches are sized correctly. The top of the crutches should rest 1-2 inches below the axilla when the crutch tips are slightly in front of and to the side of the feet. The patient's arms should be flexed to approximately 30~ when the handpieces are correctly positioned. When using crutches, it is important not to lean on the crutches, as constant pressure on the axilla can lead to brachial plexus injury. It is also important not to wear slippers or shoes without backs when using crutches. While walking, the weight of the patient should be supported entirely by the handpieces of the crutches. To walk on a flat surface, both crutches should be placed forward while supporting weight on the uninjured extremity. If the injured extremity is to bear no weight, do not let this extremity touch the floor. If partial weight bearing is acceptable, place the foot of the injured extremity in line with the crutches which have been moved forward. Then take a normal step, moving the uninjured leg between the crutches and past the rubber tip of the crutches. Walk slowly and carefully while using crutches. To walk up stairs with crutches, stand as close to the step as possible, place both crutches under one arm and grasp the rail with the other hand. If there is no rail, keep one crutch in each hand and use the handpieces for support. Place the crutch tips as close as possible to the first step, put weight on the crutches and rail and hop onto the step. Bring the crutches up to this step and repeat the procedure. To walk down stairs, follow the same routine for crutch placement under one arm. Place the crutches on the lower step, extend the injured extremity forward off the step, put
49
weight on the crutches and tail and lox~r the uninjured leg to the next step. Step walking should be done slowly and carefully. Loose footwear or socks should not be worn while using crutches. Children less than 4 years of age may not be able to manipulate crutches carefully or effectively, therefore, these children may be better suited to use a walker or wheelchair.
Practising and teaching the technique : The above methods of splinting and the proper use of crutches can be easily practised. Students can use the materials mentioned on each other to improve their skills. 9. PRINCIPLES OF WOUND MANAGEMENT The primary objectives of wound care are to restore function, to produce optimum cosmesis, and to avoid infection. The wound must be adequately examined. Dressings should be removed and clotted blood and debris gently washed from the wound using a physiologic solution such as normal saline. If appropriate, a small amount of hair may be shaved from the vicinity of the wound site. Eyebrows should be left intact to provide proper landmarks for repair. When the wound can be fully visualized, the decision to suture or allow repair by secondary intention must be made. In general, the less the delay in closing, the better the cosmetic result. We use 12 hours from occurrence of the injury (18 hours for facial wounds) as the time interval beyond which we will not attempt primary closure. This figure is somewhat arbitrary, however, and some perform delayed primary closure
50
TIlE INDIAN JOURNAL OF PEDIATRICS
48-72 hours after a wound has occurred. Infected or infection-prone wounds such as human bites of the hand should generally not undergo primary closure. Alternatively, these wounds can be cleaned, packed, treated with systemic antibiotics, and referred for delayed primary closure 48-72 hours later, when the absence of infection has been established. Performing the task :
Prior to further cleansing, debridement, and inspection, adequate anesthesia should be achieved. There are several ways in which this can be accomplished. Perhaps the most common technique is the local injection of lidocaine. Although it is supplied in 2 concentrations (1% and 2%), the I% solu[i~n usually affords adequate anesthesia while" minimizing the likelihood of ovcr"~ose. The maximum injected dose should not exceed 4.5 mg/kg. Symptoms of toxicity include drowsiness, disorientation, muscle twitching, seizures, myocardial and/or circulatory depression.27 Lidocaine is also available in combination with epinephrine. The latter agent is added to provide effective hemostasis. Because of its vasoconstrictive effects, epinephrine should not be injected into end organs such as the nose, finger tips, and penis. In combination with epinephrine, the total lidocaine dose should not exeed 7 mg/kg. The onset of action of lidocaine is approximately 5 minutes, and duration of action 90-200 minutes. Prior to injection, sensation distal to the injury should be documented. The lidocaine should be injected as a shield block approximately 1 cm away from the wound edge. A clean wound may be infiltrated through the margin of the wound. Contain inated lacerations should be anesthetized by injecting through intact skin
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surrounding the wound. An alternative topical anesthetic combines tetracaine (0.5%), adrenaline (1 : 2000), and cocaine (11.8%) and is commonly referred to as TAC. 2s This solution is applied to the open wound by either direct instillation or via a saturated gauze pad or cotton ball with firm pressure for ten minutes prior to suturing. Although initial reports in the medical literature have shown this to be an effective method of anesthesia, our experience has shown that one must pay attention to the proper application of this solution in order to maximize its effectiveness. TAC should not be used on mucous membranes because of the possibility of rapid drug absorption which can cause seizures and death. Because of its vasoconstrictive effects, TAC should not be used on end-organs. Although comparative studies of TAC and other anesthetic agents have not identified serious side effects to date, these studies have been limited by their small population sizes. Following the achievement of adequate anesthesia, thorough cleansing and judicious debridement should take place to prevent wound infection.29.3o Our protocol for wound cleansing calls for irrigation of an average 2-5 cm wound with at least 100-200 cc of normal saline. We utilize a 20 cc (or larger) syringe and an 18 gauge intravenous catheter to inject a firm stream of irrigating solution into the open wound. Embedded foreign material may be extracted from the wound with fine forceps. If multiple small foreign bodies are present, the wound should be gently scrubbed with a surgical brush. Roentgenograms may be of further help in locating either glass or metal objects which are not obvious on direct inspection.
SELBST ET AL : TEACItlNG TECIINICAL SKILLS
All necrotic skin, discolored or free subcutaneous fat, and all fragments of tissue containing foreign bodios should be removed. Edema and cyanotic hue presage necrosis. Such areas should be removed to reduce the incidence of infection. Likewise, a'regular lacerations can be carefully trimmed .'or the best cosmetic effect. During cleansing and debridement, careful examination of tile wound should also take place. Deep structures should be thoroughly explored and repaired. It is imperative that full function be restored prior to closure of the skin. When the need for repair exceeds the capabilities of the examining physician, appropriate consultations should be placed. The selection of appropriate closure material is dependent upon the individual characteristics of the wound. Currently, three different types of closures are available. In our Emergency Department, absorbable and non-absorbable sutures and tape closures are most commonly used. Each of these different closure materials is used for a different purpose. Tape is primarily utilized in lacerations which extend partially through the dennis. It can also be uscd in conjunction with sutures for repair of full thickness lacerations. The usefulness of tape is limited by its adherence to the wound margins. Therefore, it should not be used in areas of moisture or over flexor surfaces of joints. Tape will generally peel from the skin surface within 3-5 days, and need not require removal by a physician. Suture material is manufactured in two basic types, absorbable and non-absorbable. Absorbable sutures such as vicryl and chromic gut are used below the skin surface to close empty spaces between tissues separated as a result of the injury. This
51
suture is also used to close intraoral wounds. Non-absorbable sutures such as nylon and polypropylene are most commonly utilized in skin surface closure. Needles also are manufactured in many forms, including cuticular, plastic, and reverse cutting, and in several sizes : 3/8 and 1/2 circle. Individual physicians might develop specific preferences ; however, a 3/8 circle reverse cutting needle has proven to be quite versatile. Suture also is produced in many sizes. When selecting closure materials, the physician should always use the smallest suture needed to proximate the edges of the wound. Recommended suture sizes are as follows : Tissue type
Fascia Dermis Skin Oral mucosa
Suture size
4-0 4-0 4-0 3-0
to 2-0 to 5-0 to 7-0 to 4-0
A detailed description of proper suture technique is beyond the scope of this article. However, certain basic principles apply to all wound closures : A. It is better to use smaller sutures placed closer together than larger sutures placed further apart. B. Wound edges should only be approximated to accommodate edema which occurs after closure ; tissue should not be strangulated. C. To assure optimal cosmetic results, wound edges should be everted when closed, rather than inverted. Post-repair care is often as important as what precedes it. Beyond its esthetic
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TIlE INDIAN JOURNAL OF PEDIATRICS
appeal, a proper dressing provides : protection, absorption, compression, and immobilization. The technique which we utilize involves the application of a nonadherent sterile dressing to cover the wound, followed by a second layer of absorbent gauze, and a third protective layer of absorbent gauze, to stabilize the other two. When dressing the wound, nearby joints are generally immobilized to reduce stress across the wound. The decision to treat with antibiotics depends upon the relative risk of infection. Wounds which were particularly dirty or deep might be more likely to develop infection, and might benefit from expectant treatment with an antimicrobial agent, like crythromycin or a semi-synthetic penicillin. Similarly, those wounds known to be at high risk of secondary infection such as bite wounds of the hand, should receive antibiotic prophylaxis, like amoxicillin clavulanate. Tetanus status should always be ascertained and immunization given in accordance with Red Book recommendations.31 Discharge instructions should be complete, but succinct and expressed in easily understandable terms. Patients and/or parents should be advised to elevate injured areas when possible. A sling can often provide this function for an upper extremity injury. When possible, follow-up care should be arranged for 24-48 hours after repairs. This provides the physician with the opportunity to reinspect the wound for signs of infection and adequacy of healing, and with the opportunity to reinforce wound care principles with the patient and/or his/her parents. Finally, a follow-up appointment for suture removal should be scheduled. The
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varying repair capabilities of different body parts indicate that the proper time of suture removal is dependent upon the location of the injury. We use the following guidelines for the timing of suture removal : Wound
Delay to removal
Face Scalp Upper extremity Lower extremity Extensor surface joint
2-4 days 4-6 days 7-10 days 8--10 days 10--14 days
Practising and teaching the teachnique : Suturing skills can be practised using supermarket meat such as pigs' feet or chicken breasts. Simple or complicated wounds can be made in this meat and then wound repair can be supervised by experienced instructors. Acknowledgements The authors wish to acknowledge Gary Fleisher, M.D., Dee ltodge, M.D., Grace Caputo, M.D., Roy Kulick, M.D., Richard Ruddy, M.D., Bruce Gribetz, M.D., Paula Schweich, M.D., Joseph Pollack, M.D., Fred ltenretig, M.D., Mark Joffe, M.D., for their help with and participation in our APA workshop. We also acknowledge Mrs. Rose Beato and Mrs. Patricia Parkdnson for their help with this manuscript.
References 1. Intravenous teclmiques In : Textbook of Advanced Cardiac Life Support. American Heart Assoc., 1987 ; 141-153. 2. Broennle AM, Gewitz MH, Handler SD, et al. Illustrated techniques of pediatric emergency procedures. In : Fleisher G, Ludwig S (eds). Textbook of pediatric emergency medicine, Williams and Wilkins, Baltimore, MD, 1983, 1210-1289
SELBST ET AL : TEACtllNG TECIINICAL SKILLS
3. Drinker CH, Drinker KR, Lund CC. The circulation in the mammalian bone marrow. Am J Physiol 1922 ; 62 : 1-92 4. Josefson A. A new method of treatment intraosscous injections. Acta Med Scand 1934 ; 81 : 550-564 5. Tocantit, s LM, O'Neill JF. Infusion of blood and oth~- fluids into circulation via the bone marrow. Proc Soc Exp Biol Med 1940 ; 45 : 782-783 6. Spivey \VH, Lahers CM, Malone DR et al. Comparison of intraosseous, central and peripheal routes of sodium bicarbonate administration during CR in pigs. Ann Emerg Med 1985 ; 14 : 1135-1140 7. McNamaa RM, Spivey WH, Unger MD et al. Emergency applications of intraosseous infusion. J Emerg Med 1987 : 5 : 97-101 8. Rossetti VA, Thompson BM, Miller J et al. Intraosseous infusion : an alternative route of pediatric intravascular access. Ann Emerg Med 1985 ; 14 : 885-888 9. Spivey WH lntraosseous infusions. J Pediatr 1987 ; 111 . 639--643 10. Advanced Trauma Life Support Course . Instruction Manual. Committee on Trauma, American College of Surgeons, 1984, 155-179 11. Standards and Guidelines for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiac Care (ECC). JAMA 1986 ; 255 : 2841-3044. 12. Fleisher G and Ludwig S (eds) : Textbook of pediatric emergency medicine. Williams and Wilkins, Baltimore, 1983. 13. McPhersen SP. Respiratory therapy equipment. C.V. Mosby, St. Louis, Missouri 1985. 14. Kettrick RG, Ludwig S. Resuscitation pediatric basic and advanced life support. In : Fleisher G, Ludwig S (eds). Textbook of pediatric emergency medicine. Williams and Wilkins, Baltimore, MD, 1983, 1-30 15. Orlowski JP. Cardiopulmonary resuscitation in pediatric patients. Ped Clin NA 1980; 27 : 495
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16. Templeton JJ, Broennle AM. Emergency department anesthetic management. In : Fleisher G and Ludwig S (eds). Textbook of pediatric emergency medicine, Williams and Wilkins, Baltimore, MD, 1983, 43-53 17. Jennings PB, Alden ER, Brenz RW . A teaching model for pediatric intubation utilizing ketamine sedated kittens. Pediatrics 1974 ; 53 : 283-284 18. Wayne MA. Clinical evaluation of the antishock trousers : retrospective analysis of five years experience. Ann Emerg Med 1983; 12 : 342-347 19. Garcia V, Eichelberger M, Zeigler M, et al : Use of military antishock trouser ha a child. J Ped Surg 1981 ; 16 : 544-546 20. Concannon JE, Matte WM, Verhagen AD . Antishock trousers in pediatrics - a case management report. Clin Pediatr 1984 ; 23 : 78-80 21. Brunnette DG, Fifield G, Ruiz E. Use of pneumatic antishock trousers in the management of pediatric pelvic hemorrhage. Ped Emerg Care 1987 ; 3 : 86-90 22. Oertel T, Loehr MM. Bee sting anaphylaxis. The use of medical antishock trousers. Ann Emerg Med 1984 ; 13 : 459--461 23. Pcpe PE, Bass RR, Mattox KL. Clinical trials of the pneumatic antishock garment in the urban-prehospital setting. Ann Emerg Med 1986 ; 15 : 1407-1410 24. Stair TO. The mechanism of MAST : stalking file elusive autotrams fusion. Am J EmergMed 1983 ; 1 : 112-113 25. American College of Surgeons Committee on Trauma : Advanced trauma life support course manual, 1985, Chapter 3, Shock, 179-191. 26. Roberts JR and Hedges JR. Clinical procedures in emergency medicine, W.B. Saunders, 1985, 650-660 27. Alfano SN, Leicht MJ, Skiendzielewski J J, et al. Lidocaine toxicity following subcutaneous administration. Ann Emerg Med 1984 ; 13 : 465--467 28. Pryor GJ, Kilpatrick WR, Opp DR. Local
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anesthesia in minor lacerations . Topical TAC vs. lidocaine infiltration. Ann Emerg Med 1980 ; 9 : 568-571 29. Callahan M. Treatment of common dog bites: infection risk factors. J Am Coll Emerg Phys 1978 ; 7 : 83-87 30. Stevenson TR, Thacker JG, Rodeheaver GT,
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et al. Cleansing the traumatic wounds by high pressure syringe irrigation. J Am Coil Emerg Phys 1976 ; 5 9 17-21 31. Committee on Infectious Diseases, American Academy of Pediatrics : Red Book, A.A.P., Elk Grove, IL., 1986, 355-359.
What Causes Cerebral Palsy? Several studies challenge the traditionally held views of the etiology of cerebral palsy (CP). It is reported that the introduction of modern perinatal monitoring has reduced the incidence of CP only among certair~ high risk infants, including those of very low birth weight ones. Recent population-based studies showed that hemiplegia was significantly associated with intrapartum factors, while cerebral diplegia was associated with immaturity, and to a smaller extent with intraventricular hemorrhage and seizures. Use of cranial ultrasound studies have led to the recognition that periventricular hemorrhage occurs in very preterm infants, and are often unilateral. In contrast, hypoxic-ischaemic lesions occur at any gestation and are usually bilateral ; the site of lesion depends on the gestation : the watershed subcortical areas are especia]ry vulnerable in infants of 34 weeks or more in gestation, while periventricular lesions are common in infants born before 33 weeks. Correlation of structural lesions of the brain revealed by ultrasound with subsequent neurologic lesions would be useful. Abstracted from Lancet 1988 ;ii : 142-143.