a b s t r a c t

Purpose: The aim of this study is to identify the neurologic outcome of hanging patients and prognostic factors. Materials and Methods: We retrospectively investigated comatose hanging patients who arrived at the emergency departments (EDs) of twelve academic tertiary care centers during a period of seven years (2006-2012). Patients were analyzed separately according to whether out-of-hospital cardiac arrest (OHCA) occurred or not. The neu- rologic outcome was evaluated using the cerebral performance category at the time of hospital discharge. Results: A total of 1118 patients were admitted to the ED after hanging attempts. There were 159 comatose pa- tients who did not experience OHCA. Twelve (7.5%) of 159 patients were discharged from the hospital with a Poor neurologic outcome (CPC 3-5). These 12 patients received only conservative management without thera- peutic hypothermia. On multivariate logistic regression analysis, mental state upon ED arrival and arterial pH were predicting factors for poor prognosis. One hundred twenty-one patients suffered OHCA and experienced re- stored spontaneous circulation after cardiopulmonary resuscitation. Among them, only five (4.1%) patients re- covered consciousness to the level of CPC 1-2. The initial arterial pH and HCO^- were prognostic factors in

hanging patients with OHCA.

3

Conclusions: Even though cardiac arrest did not occur after hanging injuries, 7.5% of patients could not recover consciousness. Therapeutic hypothermia should be considered for such patients. If OHCA occurred after the hanging injury, the proportion of patients with Good neurologic outcome was very low at 4.1%.

(C) 2016

1. Introduction

Hanging is one of the causes of Asphyxial cardiac arrest in many countries [1,2]. Victims of hanging undergo cerebral ischemia- reperfusion injury resulting in neurologic sequelae ranging from mild amnesia to severe vegetative state [2,3]. Since most hangings are suicid- al attempts by young adults [3-6], being disabled as a result of a hanging

? Notes: The authors have no financial conflicts of interest.

* Corresponding author at: Department of Emergency Medicine, Gangnam Severance Hospital, 211 Eonju-ro, Gangnam-gu, Seoul, Korea 06273. Tel.: +82 2 2019 3030;

fax: +82 2 2019 4820.

E-mail address: [email protected] (S.P. Chung).

injury is not only a catastrophic event to the patient, but also a great so- cioeconomic loss.

Since therapeutic hypothermia has been known to reduce brain damage in survivors of ventricular fibrillation cardiac arrest [7-10], the candidate list for hypothermia is gradually expanding beyond cardi- ac arrest: acute ischemic stroke, perinatal asphyxial encephalopathy, and traumatic brain injury [11-13]. Hypothermia treatment has also been attempted in hanging victims and good neurologic outcomes have been reported [14-17]. On the other hand, some of the latest stud- ies have reported that all hanging victims recovered completely if cardi- ac arrest did not occur, highlighting the uselessness of hypothermia treatment for these patients [18,19]. However, these studies included

http://dx.doi.org/10.1016/j.ajem.2016.04.036

0735-6757/(C) 2016

a small number of patients because the incidence of hanging without cardiac arrest was rare.

The prognosis of cardiac arrest patients who have sustained a hang- ing injury has been shown to be very poor [20,21], which is contrast to patients who have attempted hanging but did not experience cardiac arrest. Although, there have been several studies that investigated the outcome of hanging patients, most research has included the entire co- hort of hanging patients and has not analyzed separately patients with- out cardiac arrest [2-6,22,23]. Since obvious differences in Treatment outcomes of hanging patients exist depending on the presence of cardi- ac arrest, different treatment strategies are needed.

In this study, we investigated the outcome of hanging patients ac- cording to whether cardiac arrest occurred or not, and evaluated predicting factors for poor neurologic outcome.

1. Materials and methods
   1. Setting and design

This study was a retrospective multicenter study involving hanging patients who presented to the emergency departments (EDs) of twelve academic Tertiary care centers over a seven-year period from January 2006 to December 2012. The study protocol was approved by each hospital’s institutional review board. Patients who were discharged from the hospital during the study period with a diagnosis of Interna- tional Classification of Disease (ICD) codes X70 (intentional self-harm by hanging, strangulation, and suffocation) and T71 (asphyxiation) were identified. From the search results, we selected patients who pre- sented to the ED after hanging injuries.

Patients were divided into two groups according to the presence of out-of-hospital cardiac arrest (OHCA). We excluded some patients as follows. If patients were transferred from other hospitals after acute management, they were excluded. In patients without cardiac arrest, patients who were evaluated as alert mental status at the ED arrival were excluded. Among patients with cardiac arrest, those who did not receive cardiopulmonary resuscitation (CPR) or who could not restore spontaneous circulation after CPR were excluded.

Data collection

The patient data were retrospectively collected by analyzing hospital medical records including emergency medical service records. In terms of hanging-related characteristics, we investigated the location where the patient was discovered, tool used for the hanging, suspected hang- ing time, hanging height, hanging type (complete: where the whole body hangs off the ground; or incomplete: where some part of the body is touching the ground), and hanging mark (typical: the knot of the ligature is at the nape of the neck; atypical: the knot of the ligatures is at any site other than the nape of the neck). The patient mental state upon ED arrival, initial vital signs, and the result of the first arterial blood gas analysis were evaluated. We also investigated whether the patients were intubated or not in the ED and whether therapeutic hypothermia was performed or not. For other studies, we investigated brain comput- ed tomography (CT), brain magnetic resonance imaging (MRI) scans, and electroencephalography (EEG) to identify findings related to hyp- oxic brain damage. We also checked for fracture of the cervical spine by cervical spine CT. For patients in the cardiac arrest group, bystander CPR, arrest rhythm on ED arrival, and CPR duration were identified. Pa- tient outcome was evaluated according to the neurological function of

Fig. 1. The number of hanging patients and neurologic outcome ED, emergency department; DOA, death on arrival; CPR, cardiopulmonary resuscitation; CPC, cerebral performance category.

the patient at the time of hospital discharge. Cerebral performance cat- egory (CPC) scores of 1 and 2 were classified as good neurologic out- comes and CPC scores of 3-5 (including death) were classified as poor neurologic outcomes.

Statistical analysis

Comparisons between the good and poor neurologic outcome groups were performed using Mann-Whitney U test for continuous var- iables and Chi-squared test or Fisher’s exact test for dichotomous vari- ables. To evaluate predicting factors for poor neurologic outcome, multivariate logistic regression analysis was performed using backward methods, because the number of events was too small in terms of the one-in-ten rule (variables were selected using the criteria of p-value b 0.1, starting with all variables). Because of large point estimates for the variable of mental status, the firth correction was used. All statistical analyses were performed using SAS 9.2 (SAS Institute Inc., Cary, NC, USA). A p-value b 0.05 was considered statistically significant.

arrests happened within 30 minutes after ED arrival. All three patients had Restored spontaneous circulation, but two patients eventually died. A brain CT was performed in 10 patients, and only one patient had cerebral edema. All brain CTs were performed on the first day. Six patients underwent a brain MRI, and cerebral ischemia was observed in all cases. Cerebral dysfunction was determined by EEG in three pa- tients. One 85-year-old patient was not intubated because a legal guard- ian refused all invasive treatments. No patients received therapeutic hypothermia.

3.3. Hanging patients presenting with cardiac arrest

Table 3 shows comparisons between good and poor neurologic out- come groups in hanging patients with cardiac arrest. Among 121 pa-

Table 1 Comparison between good and poor neurologic outcome group of hanging patients with- out cardiac arrest

1. Results
   1. Overview of hanging patients

	Age	41.0 (32.0, 52.0)	32.5 (27.8, 60.8)	0.236
During the seven-year period, a total of 1118 patients presented to	Female, n (%)	69 (46.9)	9 (75.0)	0.076

Neurologic outcome

Characteristics Good Poor P-value

(N = 147) (N = 12)

the EDs after a hanging injury (Fig. 1). Of these, 64 patients who were transferred from other hospitals and 23 patients whose medical record were lost were excluded. Among 1031 patients who arrived at the ED directly, 650 patients experienced cardiac arrest prior or at the time of ED arrival, and 381 patients did not. Among the 381 patients without cardiac arrest, 222 patients were excluded because they were evaluated as have an alert mental status on arrival at the ED. Among the 650 pa- tients with cardiac arrest, 435 patients who did not receive CPR and

94 patients who could not restore spontaneous circulation were excluded.

As a result, 159 comatose patients without cardiac arrest and 121 pa- tients who were successfully resuscitated from cardiac arrest were in- cluded in the analysis. The mean age of these patients was 42.9 +- 15.8 years, and 48.9% were female. The most common location where pa- tients were found was the bathroom (34.0%) and bedroom (26.4%). A string was the most commonly used item in 31.2% patients, and cloth was second, followed by necktie, wire, and belt. The mean hanging time was 11.1 +- 9.6 minutes, and the mean hanging height was

1.7 +- 1.1 m. Complete type accounted for 28.0% of hanging patients and 55.9% patients showed a typical hanging mark.

Hanging patients presenting without cardiac arrest

Table 1 shows comparisons between good and poor neurologic out- come groups of hanging patients who arrived at the ED without cardiac arrest. Among 151 patients, 12 (7.5%) patients could not have con- sciousness restored and were discharged with a poor neurologic out- come. Patients with a poor neurologic outcome showed more decreased mental status at ED arrival than patients with a good neuro- logic outcome (P b .001). The first measured vital signs in the ED were similar in both groups. In terms of arterial blood gas analysis, there was a significant difference in arterial pH (7.34 vs. 7.21, P b .001) and base excess (- 5.9 vs. -13.0, P = .004). Endotracheal intubation was performed in 93 (63.3%) patients with good neurologic outcome and 11 (91.7%) patients with a bad neurologic outcome. Only seven patients with a good neurologic outcome received therapeutic hypothermia. A total of 119 (74.8%) patients received a cervical spine CT, and one pa- tient was diagnosed with a fracture of the temporal styloid process.

Table 2 reviews the 12 poor neurologic outcome patients. Whereas nine females were under the age of 40, three males were over the age of 65. All 12 patients showed a mental status below stupor upon ED ar- rival. In-hospital cardiac arrest occurred in three patients, and all cardiac

Hanging time (min), n (%) 0.080

<= 10 82 (55.8) 3 (25.0)

N 10	14 (9.5)	1 (8.3)
Unknown	51 (34.7)	8 (66.7)
Height (m), n (%) 1.0-1.5	33 (22.4)	0.614 2 (14.3)
N 1.6	42 (28.6)	3 (21.4)
Unknown	72 (49.0)	9 (64.3)
Hanging type, n (%)			0.166
Complete	20 (13.6)	3 (21.4)
Incomplete	87 (59.2)	5 (35.7)
Unknown	40 (27.2)	6 (42.9)
Hanging mark, n (%)			0.199
Typical	48 (32.7)	5 (35.7)
Atypical	56 (38.1)	2 (14.3)
No mark	3 (2.0)	0
Unknown	40 (27.2)	7 (50.0)
Mental status on arrival,			b 0.001
n (%)
Drowsy	34 (23.1)	0
Stupor	82 (55.8)	2 (16.7)
Semicoma	26 (17.7)	3 (25.0)
Coma	5 (3.4)	7 (58.3)
Vital signs
SBP (mmHg)	110.0 (96.0, 135.0)	110.0 (90.0, 140.0)	0.740
DBP(mmHg) PR (bpm) RR (bpm)	70.0 (60.0, 80.0) 98.0 (85.0, 113.0) 20.0 (18.0, 22.0)	70.0 (60.0, 81.0) 100.0 (80.0, 131.0) 18.0 (12.0, 20.0)	0.942 0.740 0.045
BT (?C)	36.5 (36.0, 36.7)	36.1 (36.0, 36.5)	0.141
ABGA, median (IQR)
pH	7.34 (7.29, 7.39)	7.21 (7.04, 7.29)	b 0.001
pCO2 (mmHg)	36.0 (31.0, 40.0)	39.5 (31.5, 65.0)	0.246
pO2 (mmHg)	108.1 (81.1, 171.0)	107.2 (78.5, 250.9)	0.795
Base excess (mmol/L)	-5.9 (-9.4,	-13.0, (-17.0,	0.004
	-2.2)	-10.5)
-	19.3 (15.4, 22.1)	16.4 (13.1, 18.1)	0.086
Endotracheal intubation, n	93 (63.3)	11 (91.7)	0.059
(%)
Therapeutic hypothermia,	7 (4.8)	0	1.000
n (%)
Fracture on cervical spine CT,	1/109 (0.9)	0/10	1.000
n (%)
Cerebral edema on brain CT,	11/124 (8.9)	1/10 (10.0)	1.000
n (%)
Ischemia on brain MRI,	2/42 (4.8)	6/6 (100.0)	b 0.001
n (%)
Dysfunction on EEG, n (%)	11/27 (40.7)	3/3 (100.0)	0.090

HCO₃ (mmol/L)

SBP, systolic blood pressure; DBP, diastolic blood pressure; PR, pulse rate; RR, respiratory rate; BT, body temperature; ABGA, arterial blood gas analysis; pCO₂, partial pressure of carbon dioxide; pO₂, partial pressure of oxygen, HCO^-, bicarbonate ion; CT, computed to- mography; MRI, magnetic resonance imaging; EEG, electroencephalography.

3

tients who suffered OHCA, only five (4.1%) patients were discharged with a good neurologic outcome. They received pre-hospital CPR within a shorter period of time (5.0 minutes vs. 13.0 minutes, P = .043), showed better mental status after ROSC (P b .001), and had less acidic arterial blood (7.28 vs. 6.97, P = .019) than patients with a poor neuro- logic outcome. One of five patients with a good neurologic outcome had cerebral edema on brain CT.

3.4. Prognostic factors

Logistic regression analysis was performed to find predictors of poor neurologic outcomes (Table 4). Among all patients, the presence of OHCA, hanging time, hanging type, hanging mark, mental status, vital signs, ABGA, endotracheal intubation, therapeutic hypothermia, brain CT, brain MRI, and EEG showed significant differences between good and poor neurologic outcomes, and were included in the multivariate analysis. As a result, the presence of OHCA, coma mental status, and ar- terial pH were predicting factors for a poor neurologic outcome. Mental status on ED arrival and arterial pH were also predicting factors in hang- ing patients without OHCA. Variables included in the analysis were sex, hanging time, mental status on arrival, arterial pH, base excess, HCO^-, endotracheal intubation, and brain MRI. In patients with OHCA, the du- ration of pre-hospital CPR, mental status after ROSC, arterial pH, base excess, HCO^-, brain MRI, and EEG were included in the analysis, and consequently arterial pH and HCO^- were significant factors.

3

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1. Discussion

Since there is lack of previous studies and no treatment guidelines, hanging patients have been treated based on the doctor’s individual

experience. We wanted to be able to suggest more practical information by presenting the results according to the presence of cardiac arrest, separately. In this study, among patients who did not suffer cardiac ar- rest at the scene but showed comatose mental state upon ED arrival, 7.5% had a poor neurologic outcome of CPC 3-5 at the time of hospital discharge. If cardiac arrest occurred at the scene, only 4.1% of patients could restore their ability of life to a level of CPC 1-2.

There are three studies that have separately studied the outcome of hanging patients who did not experience cardiac arrest [14,18,19]. Wee, et al. [19] and Lee, et al. [18] reported that all hanging patients without cardiac arrest discharged with a CPC of 1 regardless of therapeutic hypo- thermia and pointed out that therapeutic hypothermia appears to be unnecessary. However, both studies included only a small number of patients (twenty-one and nine, respectively). Borgquist, et al. [14] re- ported that among ten hanging patients without cardiac arrest, two pa- tients who did not receive hypothermia therapy had a poor outcome. But since both of patients died in-hospital and the number of patients was small, they could not insist on the need for therapeutic hypother- mia. In our study, among 159 patients who were admitted to the ED after a hanging injury but did not suffer OHCA, ten patients were discharged with a poor neurologic outcome of CPC 3-5, and two pa- tients died in the hospital. Unfortunately, no one received therapeutic hypothermia, which might be the only way to reduce brain ischemia and improve neurologic outcome. Some cases of comatose survivors after a hanging attempt who have recovered completely with therapeu- tic hypothermia have been reported [15,16]. Considering that most hanging victims recover completely with only conservative manage- ment, these cases may not be something worth reporting. But it is obvi- ously important to remember that there is a minority of patients who do not recover their consciousness, and therapeutic hypothermia should be

Table 2

Overview of hanging patients who did not suffer out-of hospital cardiac arrest but discharged with poor neurologic outcome

No	Sex	Age (year)	Hanging time (min)	Hanging height (m)	Hanging type	Hanging mark	Mental status on ED arrival	GCS	Pupil size	pupil light reflex	SBP on ED arrival	Arterial pH	Base excess (mmol/l)
1	F	21	-	-	-	-	coma	3	1/1	-/-	100	7.290	-10.5
2	F	26	N 10	2.0	complete	atypical	coma	4	3/3	+/+	114	7.234	-17.0
3	F	27	-	1.7	incomplete	typical	coma	3	5/5	-	uncheckable	6.915	-19.6
4	F	30	<= 10	-	incomplete	-	stupor	-	3/3	+/+	115	7.196	-14.3
5	F	32	<= 10	1.5	incomplete	-	semicoma	-	5/5	+/+	169	7.085	-11.7
6	F	32	-	-	-	-	coma	3	3/3	+/+	110	7.289	-15.1
7	F	33	-	-	-	typical	coma	3	5/5	-/-	90	6.800	uncheckable
8	F	33	<= 10	2.0	complete	-	coma	3	6/6	-/-	71	7.081	-18.8
9	F	36	-	-	-	-	semicoma	4	-	-	90	7.219	-10.8
10	M	69	-	-	-	typical	coma	3	8/8	-/-	140	7.020	-13.0
11	M	78	-	-	incomplete	-	semicoma	5	8/4	+/+	108	7.310	2.5
12	M	85	-	1.0	incomplete	atypical	stupor	-	3/3	+/+	140	7.430	1.0
No	Time to	Arrest	CPR time	Cervical	Brain CT	Brain	EEG (day)	Intubation	Therapeutic	Hospital	CPC at
1	cardiac arrest (min) -	rhythm	(min) -	spine CT (day) normal (1)	(day) -	MRI (day) -	-	Y	hypothermia N	stay (day) 16	discharge 4
2 3	- 30	Asystole	- 3	normal (1) normal (1)	normal (1) normal (1)	ischemia (3) ischemia	dysfunction (4) -	Y Y	N N	10 22	4 3
4	-		-	normal (1)	normal (1)	(12) -	-	Y	N	10	5
5 6	- -		- -	normal (1) HCD (1)	normal (1) normal (1)	ischemia (6) ischemia	dysfunction (7) -	Y Y	N N	37 86	3 3
7	4	Asystole	4	normal (1)	normal (1)	(20) -	-	Y	N	2	expire
8 9	- -		- -	normal (1) -	edema (1) normal (1)	ischemia (2) -	dysfunction (3) -	Y Y	N N	78 6	3 3
10 11	6 -	Asystole	8 -	- normal (1)	- normal (1)	ischemia (3) -	- -	Y Y	N N	8 5	expire 4
12	-		-	normal (1)	normal (1)	-	-	N	N	12	3

ED, emergency department; GCS, Glasgow Coma Scale; SBP, systolic blood pressure; CPR, cardiopulmonary resuscitation; CT, computed tomography; MRI, magnetic resonance imaging; EEG, electroencephalography; CPC, cerebral performance category; HCD, herniated cervical disc.

Table 3

Comparison between good and poor neurologic outcome group of hanging patients with cardiac arrest

Neurologic outcome

	Characteristics		Good		Poor		P-value
			(N = 5)		(N = 116)
	Age		50.0 (43.0, 66.0)		39.0 (31.3, 50.8)		0.069
	Female, n (%)		2 (40.0)		57 (49.1)		1.000
	Hanging time (min), n (%)						0.469
	<= 10		2 (40.0)		38 (32.8)
	N 10		2 (40.0)		25 (21.6)
	Unknown		1 (20.0)		53 (45.7)
	Height (m), n (%)						0.947

1.0-1.5 1 (20.0) 18 (15.5)

N 1.6 1 (20.0) 29 (25.0)

Unknown 3 (60.0) 69 (59.5)

Hanging type, n (%)	0.365
Complete	0	31 (26.7)
Incomplete	2 (40.0)	42 (36.2)
Unknown	3 (60.0)	43 (37.1)
Hanging mark, n (%)	0.943

Typical 2 (40.0) 47 (40.5)

Atypical 1 (20.0) 17 (14.7)

Unknown 2 (40.0) 52 (44.8)

Cardiac arrest related factors

Shockable rhythm, n (%) 0 1 (0.9) N 0.999

Bystander CPR, n (%) 3 (60.0) 31 (26.7) 0.134

CPR duration (min) 10.0 (3.0, 32.0) 22.0 (16.0, 29.0) 0.192

Pre-hospital 5.0 (1.0-8.0) 13.0 (5.0-18.3) 0.043

ED 4.0 (0, 27.0) 8.0 (5.0-15.0) 0.381

The prognosis of a hanging precipitated OHCA is much worse than cardiac arrest due to other causes [20,21]. In the Deasy, et al. study [20], only seven (3.3%) of 61 patients who achieved ROSC from hanging-induced OHCA survived until hospital discharge. Shin, et al.

[21] Investigated 105 hanging-induced OHCA patients who were treat- ed with therapeutic hypothermia, and reported that the rate of survival until discharge was 42.9% and the proportion of good neurologic out- comes of CPC 1-2 was 5.7%. They said that the outcome of hanging pa- tients was worse than that of non-hanging patients despite hypothermia therapy, but the survival discharge rate of hanging pa- tients increased after therapeutic hypothermia even though the neuro- logic outcome was not improved compared with previous studies. In our patients with OHCA, 57.0% survived until hospital discharge, and 4.1% recovered to CPC 1-2. Therapeutic hypothermia was performed more frequently in patients with a good neurologic outcome, but we could not detect statistical significance. Until now, there has been no randomized controlled study of the effectiveness of therapeutic hypo- thermia for cardiac arrest patients due to hanging. Most of them were usually unwitnessed and of Non-shockable rhythm, and thereby result- ed in a poor prognosis [20,21,24]. We should continue to study how much therapeutic hypothermia overcomes these unfavorable condi- tions of hanging-induced cardiac arrest.

In this study, the presence of cardiac arrest, mental status at ED ar- rival or after ROSC, and arterial pH were predictors of poor neurologic outcome after hanging injury. We have found similar results in previous studies, all of which included hanging patients regardless of cardiac ar-

rest [4,6,22,23]. Penney, et al. [4] reviewed 42 patients and reported that

Mental status after ROSC, n (%)

Stupor 1 (20.0) 3 (2.6)

Semicoma 2 (40.0) 4 (3.4)

Coma 2 (40.0) 109 (94.0)

ABGA, median (IQR)

b0.001

the Glosgow Coma Scale (GCS) on arrival influenced the neurologic out- come and all victims who experienced cardiac arrest at the scene did not survive. Matsuyama, et al. [23] compared 11 survivors and 37 non- survivors and suggested the presence of cardiac arrest at the scene,

GCS on arrival, and hanging time as related factors of survival. In our

pH 7.28 (7.07, 7.40) 6.97 (6.85, 7.14) 0.019

pCO2 (mmHg)	35.0 (27.4, 68.6)	59.9 (38.5, 77.1)	0.242	study, the estimated hanging time was shown to be related to the neu-
pO2 (mmHg) Base excess (mmol/L)	57.0 (40.9, 131.0) -4.7 (-16.7,	111.1 (69.4, 226.0) -18.0 (-21.7,	0.105 0.020	rologic outcome. However, we could not identify statistical significance because of a large number of missing data. Another meaningful variable

-4.7)

-

-14.4)

in our study was arterial pH, which was significant in both cardiac arrest

HCO₃ (mmol/L) 20.5 (13.7, 21.1) 12.2 (10.4, 15.0) 0.019

Therapeutic hypothermia, n (%)

Fracture on cervical spine CT, n (%)

Cerebral edema on brain CT, n (%)

3 (60.0) 38 (32.8) 0.335

0/5 1/82 (1.2) 1.000

1/5 (20.0) 59/93 (63.4) 0.073

and non-cardiac arrest. Matsuyama, et al. [23] also reported that the ar- terial pH was different between survivors and non-survivors. One more potential factor might be an anoxic finding on CT scan [3,22]. However, in our study, many patients with a poor neurologic outcome did not show ischemic findings on brain CT, especially patients who did not suf-

Ischemia on brain MRI, n (%) 0/2 12/14 (85.7) 0.050

Dysfunction on EEG, n (%) 0/1 44/44 (97.8) 0.022

CPR, cardiopulmonary resuscitation; ED, emergency department; ROSC, return of sponta- neous circulation; ABGA, arterial blood gas analysis; pCO₂, partial pressure of carbon diox- ide; pO₂, partial pressure of oxygen, HCO^-, bicarbonate ion; CT, computed tomography; MRI, magnetic resonance imaging; EEG, electroencephalography.

3

considered for these patients. Knowing how to anticipate the patient who will become permanently disabled is critical. In this study, coma mental status and lower arterial pH predicted a poor neurologic outcome.

fer cardiac arrest at the scene. This could be because they had a brain CT

predominantly on the day when the hanging occurred, which is too early for an ischemic change to appear on a CT scan.

There are several limitations of this study. First, due to the retrospec- tive design of the study, variables related to the hanging event had a large number of missing data. It was not easy for the witness to describe the scene of the hanging accurately. Furthermore, it was difficult for the physician to obtain precise information and to leave it in the medical re- cord in an emergent situation. Factors such as hanging time, height of hanging, hanging type, and hanging mark may be important in predicting the prognosis, but we could not prove it in this study. Second,

Table 4

Predicting factors for poor neurologic outcome of hanging patients

			Total			Without cardiac arrest			With cardiac arrest
	Characteristics		OR (95% CI)	P-value		OR (95% CI)	P-value		OR (95% CI)	P-value
	Presence of cardiac arrest		19.037(5.446-66.541)	b 0.001
	Mental status
	Drowsy		1			1
	Stupor		2.704(0.128-57.185)	0.523		2.02(0.081-50.572)	0.669
	Semicoma		6.525(0.291-146.159)	0.237		10.342(0.42-254-602)	0.153
	Coma		51.146(2.386- N 999.999)	0.012		57.803(2.364- N 999.999)	0.013
	pH (0.1 unit)		0.571(0.396-0.825)	0.003		0.193(0.297-0.819)	0.006		0.591 (0.358-0.975)	0.040
	HCO-								0.746 (0.569-0.977)	0.034

3

OR, odds ratio; CI, confidence interval; HCO^-, bicarbonate ion.

3

despite it being a multicenter study, we could include only 12 patients who did not experience OHCA but were discharged with neurologic se- quelae and five patients who suffered cardiac arrest but recovered with- out severe disability. There may be more prognostic factors that we could not reveal in this study because of the small number of patients enrolled. Lastly, the neurologic outcome in our study was based on CPC score at the time of hospital discharge, which may differ from the long-term neurologic outcome.

1. Conclusions

We suggest that even if the hanging patient did not experience car- diac arrest prior to and at the time of ED arrival, 7.5% of comatose pa- tients could not recover their consciousness. Therapeutic hypothermia must not be overlooked in these patients. Factors that predicted poor prognosis were mental status at the time of ED arrival and arterial pH. The neurologic outcome of hanging patients with cardiac arrest was very poor, as only 4.1% patients recovered to CPC 1-2.

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