Ir J Med Sci (2009) 178:29–33 DOI 10.1007/s11845-008-0242-z
ORIGINAL ARTICLE
Alcohol, drug misuse and suicide attempts: unrecognised causes of out of hospital cardiac arrests admitted to intensive care units A. M. McLaughlin Æ J. Hardt Æ A. P. McKay Æ G. J. Fitzpatrick Æ M. B. Donnelly
Received: 15 January 2008 / Accepted: 2 October 2008 / Published online: 25 October 2008 Ó Royal Academy of Medicine in Ireland 2008
Abstract Aim To assess the contribution of alcohol, drug abuse and suicide attempts to out of hospital cardiac arrests (OHCA) who are admitted to our intensive care unit (ICU). Methods Retrospective review of all OHCA admitted to the ICU over a 2-year period. Results There were 26 OHCA. Six patients survived, all of whom had a cardiac aetiology for their arrest. Ten patients arrested due to external factors (drug misuse n = 4, alcohol excess n = 1, suicide attempts n = 4 and accidental choking n = 1). All of the patients who arrested secondary to external factors were young (37.2 ± 13.58 years), 90% were male and all died in hospital. All of the cases of drug misuse involved cocaine. Conclusion Alcohol, drug misuse and suicide attempts contribute significantly to the number of OHCA which are admitted to ICU. Moreover, cocaine usage has contributed to a number of OHCA in our study. Keywords Out of hospital cardiac arrest Drug misuse Suicide attempt Intensive care unit Cocaine Alcohol
Introduction Cardiac disease accounts for the majority of cardiopulmonary arrests and has the most favourable prognosis [1, 2]. Most studies have excluded arrests of non-cardiac aetiology or have reported only the overall results. Approximately 34% of out of hospital cardiac arrests (OHCA) are thought to be non cardiac in origin. Studies examining the aetiology of OHCA which were not due to cardiac disease report trauma, non-traumatic bleeding, intoxication, near drowning and pulmonary embolism as the most common aetiologies [3]. Studies show between 12 and 68% of OHCA spontaneously recover circulation following appropriate resuscitation and are subsequently transferred to intensive care units (ICU) or hospital wards [4–6]. There have been no studies highlighting the incidence of such cases which occur due to external factors (e.g. drug misuse, alcohol intoxication, drowning, asphyxiation, trauma, suicide attempts) in an Irish setting. Recent media attention has focused on the increased usage of cocaine in Ireland, with journalists reporting the detection of cocaine in pubs and club bathrooms; moreover, this has been reported by the National Advisory Council on Drugs in Ireland [7].
Methods A. M. McLaughlin (&) J. Hardt G. J. Fitzpatrick M. B. Donnelly Department of Intensive Care, Adelaide & Meath Hospital incorporating The National Children’s Hospital, Tallaght, Dublin 24, Ireland e-mail:
[email protected] A. P. McKay Department of Psychiatry, Adelaide & Meath Hospital, Dublin 24, Ireland
This observational retrospective record review took place in the Adelaide and Meath Hospital, Dublin, a 500-bed university teaching hospital. The ICU is a nine-bed semiopen medical-surgical unit with two isolation rooms. Patients are admitted from within the hospital and from the community or from other hospital through the accident and emergency department. The study investigated patients
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admitted to the ICU between 1 January 2006 and 31 December 2007. Data were obtained from a prospectively recorded ICU database (Acubase Critical Care 2, Acubase Ltd., Surrey, UK), where all clinical data from January 2006 were recorded. Additionally, patients’ medical notes and emergency department records were reviewed for further information. The study was approved by the hospital ethics committee. An OHCA was defined as due to cardiac aetiology where the arrest was presumed to be related to heart disease and non-cardiac aetiology where the arrest was thought to be non-cardiac in origin [8]. Furthermore, the cases in which the aetiology was non cardiac were subdivided into internal and external causes [9]. In this study, there were 13 arrests of non-cardiac origin, of which three were due to internal factors; neurological n = 2, non-traumatic haemorrhage n = 1. External aetiologies are defined as those in which the precipitant came from an exogenous source. In this study, ten cases were due to external factors; drug misuse n = 4, alcohol excess n = 1, suicide attempts n = 4, and accidental choking n = 1. In one case which we have defined as suicide, toxicology was positive for cocaine, and in another, serum alcohol level was elevated; furthermore, in one case which we have defined as drug use, toxicology was positive for alcohol. Statistical analysis: Instat Software 1998 (Graph Pad Software, Inc., San Diego, CA, USA), was used for all statistical analyses. Continuous data are presented as mean (standard deviation). Proportions are presented as number (%). Unpaired t test was used to compare means.
Table 1 Baseline data of the 26 patients admitted to the intensive care unit following out of hospital cardiac arrest Case Age/gender APACHE II score Sofa score Patient outcome 1
52/M
11
4
Alive
2
45/M
28
8
Alive
3
27/F
18
8
Alive
4
38/M
15
4
Alive
5
59/M
26
9
Dead
6
68/M
38
13
Dead
7 8
70/F 66/F
29 20
7 4
Dead Alive
9
29/M
28
8
Dead
10
52/F
22
8
Dead
11
51/M
29
9
Dead
12
74/M
32
11
Dead
13
26/M
32
10
Dead
14
47/M
33
11
Dead
15
24/M
24
13
Dead
16
73/M
30
11
Alive
17
71/M
33
9
Dead
18
43/M
27
9
Dead
19
24/M
26
9
Dead
20
61/M
35
11
Dead
21
26/M
24
9
Dead
22 23
42/M 30/M
33 26
10 12
Dead Dead
24
27/M
na
na
Dead
25
35/F
na
na
Dead
26
52/M
22
12
Dead
na data not available
Results There were 26 OHCA who were admitted to ICU during the study period. Table 1 demonstrates the baseline characteristics of the population. Eighty percent (n = 21) were male, the mean age was 46.69 ± 17.12 years. The mean APACHE II score was 26.71 ± 6.46 and admission SOFA score 9.125 ± 2.56. Six patients were discharged from hospital: five of these had no neurological deficit and one had a moderate deficit and was discharged to a nursing home, no longer capable of self care. The period of time which elapsed between witness of collapse and restoration of spontaneous cardiac output, varied from 10–40 min, however was not recorded in the majority of cases. Twenty patients did not survive, 19 died in ICU and one patient died following discharge from ICU. Table 2 divides the cohort into survivors and non survivors. Six patients survived, all of whom had a cardiac aetiology for their arrest. Twenty patients did not survive, seven due to cardiac disease, three due to medical causes, one directly related to alcohol, four due to drug misuse,
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Table 2 Comparison of survival and non-survival data according to aetiology of out of hospital cardiac arrest Survivors n = 6
Non survivors n = 20
Cardiac
6 (100%)
7 (35%)
Non cardiac
0
Medical causes
0
3 (15%)
Alcohol
0
1 (5%)
Drug OD
0
4 (20%)
Suicide
0
4 (20%)
Accidental choking
1 (5%)
four secondary to suicide attempts and one due to accidental choking. The mean APACHE II score was 20.3 ± 7.39 for survivors and 28.3 ± 4.62 for non survivors (p = 0.0029). The mean SOFA was 6.5 ± 2.9 for survivors and 10 ± 1.75 for non survivors (p = 0.0017). Table 3 compares the characteristics of those who arrested from a cardiac aetiology with those of who
31 Table 3 Comparison of survival and resuscitation data in cardiac and non-cardiac patients admitted with out of hospital cardiac arrest
Cardiac (n = 13)
Non cardiac (n = 13)
Mean age (years)
57.07 ± 14.9
36.15 ± 12.4
Male gender
9 (69%)
12 (92.3%)
Survived
6 (46%)
0
APACHE II/SOFA
25.76 ± 8/8.23 ± 2.9
27.81 ± 4.09/10.18 ± 1.6
First rhythm
NR data not recorded in the patients’ medical notes Table 4 Comparison of survival and resuscitation data in patients admitted with OHCA of non-cardiac aetiology divided into internal and external aetiologies
Ventricular fibrillation
12
1
Asystole
0
6
PEA
0
3
Not recorded
1
3
Witnessed arrest
11 (NR = 1)
4 (NR = 2)
Internal (n = 3)
External (n = 10)
Age
32.66 ± 8.32
37.2 ± 13.58
Male gender
3 (100%)
9 (90%)
Survived
0
0
APACHE II/SOFA
27.66 ± 4.7/10.33 ± 1.5
28.87 ± 4/10.12 ± 1.7
First rhythm Ventricular fibrillation
1
0
Asystole
0
6
PEA
1
2
Not recorded
1
2
Witnessed Arrest
1 witnessed/1 unwitnessed/1 NR
3 witnessed/6 unwitnessed/1 NR
arrested from a non-cardiac aetiology. The aetiology of the arrest in the non-cardiac patients was neurological n = 2, non-traumatic haemorrhage n = 1, drug misuse n = 4, alcohol excess n = 1, suicide attempts n = 4, and accidental choking n = 1. The mean age of the cardiac patients was greater than that of the non-cardiac patients (57.07 ± 14.9 vs. 36.15 ± 12.4 years) (p = 0.001). Fortysix percent (n = 6) of cardiac patients survived versus none of the non-cardiac patients. Twelve of the cardiac patients were admitted in ventricular fibrillation versus one of the non-cardiac patients. Six of the non-cardiac patients were admitted in asystole and three in pulseless electrical activity (PEA). Mean APACHE II for cardiac patients was 25.76 ± 8 and 27.81 ± 4.09 for non-cardiac patients (p = 0.4303). The mean SOFA scores of the cardiac patients was and 8.23 ± 2.9 and 10.18 ± 1.6 for non-cardiac patients (p = 0.0524). Table 4 divides the OHCA which are not due to cardiac disease arrest into aetiology by internal or external factors. In our study, 13 OHCA were deemed to be non cardiac in aetiology: internal causes accounted for three cases (23%) and external causes accounted for ten cases (77%) and none survived. The arrests due to internal factors were due to neurological disease n = 2 and non-traumatic haemorrhage n = 1. The ten cases were due to external factors as following: drug misuse n = 4, alcohol excess n = 1,
suicide attempts n = 4, accidental choking n = 1. The mean age of those who had an OHCA due to internal factors was 32.66 ± 8.32 versus 37.2 ± 13.58 years due to external factors. All of the internal cases and 90% of the external cases were male. The mean APACHE II score of the internal factors was 27.66 ± 4.7 versus 27.87 ± 4.00, the mean SOFA score was 10.33 ± 1.5 for internal factors versus 10.12 ± 1.7 for external factors. Information on the presence or absence of a witness to the arrest was incomplete; however, where data was included, 50% of arrests due to internal aetiology were witnessed, compared with 30% of those from external aetiology.
Discussion Our data demonstrate that survival from OHCA of noncardiac origin was unexpectedly lower than reported survival rates in cardiac arrests of cardiac origin, and indeed the survival rate which we report is less than that in previously published work [3, 9]. This study is the first Irish study to show the significant contribution of drug misuse, alcohol excess, and suicide attempts to OHCA with 34.6% (n = 9) of cardiac arrests being secondary to one of these factors and only one case in which the external factor was not related to these, a case of accidental choking.
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There have been two studies which have looked at the aetiology of OHCA. The first study looked at OHCA of non-cardiac origin in Helsinki over a 2-year period (1994, 1995). In this study, which exclusively examined arrests of non-cardiac origin, external causes accounted for 46.7% of cases and the survival rate was 18.7%, by comparison with 5.3% for internal cases. Predominant causes of OHCA due to external aetiology were intoxication, near drowning and trauma. A more recent study was conducted in Scotland over a 7-year period (May 1991–March 1998), and examined all cardiac arrests by aetiology [9]. In this study, external aetiology accounted for 9% of arrests. Trauma, asphyxia, drug overdose and drowning were the most common causes quoted; 16.5% of those who were admitted to the hospital (ward and ICU), survived. The survival rates in these studies are higher than that found in our study. This is likely due to the different aetiologies of the external arrests, with the majority of the arrests in our study being secondary to drug misuse; in all cases, cocaine was found either alone or in combination with other drugs. OHCA due to near drowning and airway obstruction have been associated with a better prognosis than other external causes of OHCA [10]. Initial rhythm of ventricular fibrillation, bystander-witnessed arrest, bystander-initiated cardiopulmonary resuscitation and short time intervals are factors which are associated with survival in cardiac arrest of cardiac origin [11]. In the case of OHCA of non cardiac cause, the aetiology of the arrest and the scene where the collapse occurred has been noted to be associated with survival [3]. It is not surprising that arrests which are due to alcohol, drug misuse and suicide attempts are less likely to be witnessed and therefore more likely to have a substantial delay to resuscitation and treatment than arrests due to internal causes. Furthermore, it is plausible that in cases where the arrest is secondary to illicit drug use, there may be a delay by witnesses to contact emergency services because of fear of legal or police proceedings. It is notable, that in our study, none of the patients who arrested due to external causes were in ventricular fibrillation. In the study by Kuisma and Maatta, it was noted that survival rates in patients found in asystole was higher in those who arrested from non-cardiac aetiology than those who arrested from cardiac aetiology. By contrast, survival rates are lower for ventricular fibrillation and at the same level for PEA [12] in those with non-cardiac aetiology. One of the limitations in performing such a study is the reliability of clinical suspicion alone in determining the aetiology of OHCA. Where determination of aetiology is only based on clinical suspicion, without the benefit of specialised tests or post mortem data, cases with non-cardiac aetiology will be missed [13]. Previous studies have demonstrated that when post mortems are carried out following
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an OHCA, the cause is more likely to be attributed to a noncardiac aetiology than when they are not performed [3]. In the diagnosis of cocaine misuse, serum testing has a detection window of 12 h for cocaine and 48 h for benzoylecgonine, a cocaine metabolite; urine testing (which measures benzoylecgonine) has a detection window of about 2–3 days after cocaine use, but may be positive up to 2 weeks after chronic heavy use [14, 15]. In this report, toxicology for cocaine was measured in urine analysis using a qualitative assay for benzoylecgonine. Our study demonstrated a significant number of OHCA due to external aetiologies. These predominantly occurred in young people and none survived. It is important to consider the costs associated with these deaths. In addition to the direct medical costs, indirect costs accrue due to loss of productivity secondary to premature death which may be expressed as years of potential life lost (YPLL). Additionally, intangible costs which value the pain and suffering, for the individual’s family need to be considered. Furthermore, the burden of ICU admissions which result from alcohol and drug misuse poses opportunity costs for ICU. In summary, this study demonstrates the significant burden imposed by external aetiologies in the causation of OHCA admitted to ICUs. Most of these patients are young males and the cardiac arrest is associated with a particularly poor prognosis. Significantly, many of these arrests were secondary to drug misuse with cocaine either alone or in combination with other drugs being found in all cases.
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