445

CME Article Airway and respiratory Abdullah Kaki MB CI-IB, management following Edward T Crosb 7 MO FRCPC,* Anne CP Lui MD Fr~CvCt non-lethal hanging

Purpose: q~ review the literature on airway and respiratory management following non-lethal (suicidal) hangang and to describe the anatomy, injury and pathophysiological sequelae and their impact on patient care. Source: A IVedline literature search of English-languageand English-abstracted papers for 1990-96. Keywords were: hanging; strangulation; airway obstruction; pulmonary oedema, filters were applied to limit the search to relevant cita- tions. (i.e., keywords = pulmonary oedema; filters = postobstructive, neurogenic). C~ations were then hand-culled to obtain current and relevant papers about an unusual cohort of paaents. A hand search of the bibliographies of rel- evant papers supplemented the Medline search. A review of our experience at the University of Ottawa adult hospi- tals over the last decade was also undertaken to determine the relevance of the Irterature to our clinical experiences. Principal Findings: Most victims are young men and survwors are uncommon. Laryngo-tracheal injuries, although reported in 2,3-50% of postmortem examinations, are infrequent in survivors and have little impact on airway man- agement. Spinal injuries are rare in survivors but should be excluded. Pulmonary complications including pulmonary oedema and I~ronchopneumonia are implicated in most in-hospital . Pulmonary oedema is likely due to neuro- genie factors c,r negative intrathoracic pressure. Although neurological injury determines outcome following hanging, ini- tial neurological presentation is of limited prognostic value: a poor initial condition does not exclude a good recovery. Conclusion: Airway ~njuries severe enough to interfere with airway management are uncommon after attempt- ed suicide by hanging. Irrespective of the initial neurological assessment, aggressive and early resuscitation to opti- mize cerebrai oxygenation is recommended.

Objectif : PEviser ia I~Erature publiEe sur la gestion des voies a&iennes et de la respiration apt& r&hec de suicide par pendaison et dEcrire i'anatomie, les lesions et les sEquelles physiopathologiques consEcutives et leur influence sur le traitement. Source : Ure recherche sur Nledline des articles et des rEsumEs pubtiEs en langue anglaise de 1990 ,~ 1996. Les roots clEs recherchEs Etaient : pendaison ', strangulation ; obstruction des voies aEriennes ', oed&ne pulmonaire. Des ,,filtres,, ont E16 utilisEs pour limiter la recherche aux citations pertinentes (par ex., pour les mots des : oedEme put- monare ; les liltres postobstruction et neuro~ne). Les citations ont alors Et6 triEes ~ la main pour acquErir les articles courants et at:propriEs au sujet de cette cohorte inhabituelle de patients. Une recherche visuelle darts la bibliographie des articles i~rtinents a complEtE la recherche dans Medtine. Eexp&ience clinique accumulEe darts les hEpitaux d'adultes de runiversit6 d'Ottawa a aussi Et6 analys~epour determiner sa concordance avec celle de la littErature. Principales constatations : La ptupart des victimes sont des hommes jeunes et les survivants sont rares. Les lesions laryngotrachEales retrouvEes ,~ I'autopsie dans 20 h 50% des cas. sont rares chez les survivants et ont tr& peu d'impact,.; sur la gestion des voles a&iennes. Les blessures rachidiennes aussi sont rares chez les survivants mais devraiert 6tre recherchEes. Les complications pulmonaires dont roedEme et la bronchopneumonie inter- viennent corrme cause dans la plupart des dEcEs hospitaliers. I'oedEme pulmonaire est vr-~semblablement d'o- rigine neurologique ou barotraumatique par pression negative intrathoracique. Bien qu'apr~s la pendaison, la lesion neurologique determine rissue, [a condition initiale de rEtat neurologique n'a qu'une valeur pronostique limitEe ; une condition initiale mediocre n'exclut pas une bonne rEcupEration. Conclusion : AprEs une tentative de suicide par pendaison, les lesions des voles aEriennes sont rarement assez graves pour nuire ~ leur contrEle. IndEpendamment de revaluation neurologique initiale, une reanimation agres- sive et prEco~e s'impose pour optimaliser roxygEnation du cerveau.

From the Department,s of Anaesthesia, Ottawa General Hospital* and Ottawa Civic Hospital,t University of Ottawa. Address corresponde'nee ~0: Dr. Edward T. Crosby, Department of Anaesthesia, Ottawa General Hospital, Room 2600, Towcr 3,501 Smyth Road, Ottawa, Ontario, Canada, K1H 8L6; Phone: 613-737-8187; Fax: 613-737-8189; E-mail [email protected] Accepted for publication January I1, 1997,

CAN j ANAESTH 1997 / 44:4 / pp 44.5-450 446 CANADIAN JOURNAL OF ANAESTHESIA

ANGING is the most common form of strangulation injury. 1 Other forms include manual, postural, and ligature strangula- H tion. Hanging occurs when pressure is exerted on the neck by an external mechanism, usually a rope, and the applied pressure is increased by the sus- pended weight of the victim's body. Hanging can occur from virtually any position. Completehanging applies to situations in which the victim is fully suspended and the term incompletehanging is used for other positions. The site of placement of the ligature knot is important: typi- cal hanging refers to the situation where the point of suspension (knot) is placed over occiput. Typical place- ment has the greatest ability to result in arterial occlu- sion.1 In classic judicial hanging, unless the drop was at least equal to the height of the victim, there was usually FIGURE 1 Anatomy of the neck structures affected by strangu- no injury to the cord, fracture of the spine, or fracture lation. (From Issersonl), with permission. to the base of the skull; occurred by asphyxiation. In longer judicial drops, the most common spinal injury was disjointing of the second from the third cervical ver- tebra and bilateral fractures of the arch of the second described after postmortem examination and may not vertebra, the hangman'sfracture. Occasionally, the dis- occur in survivors. The vertebral arteries course jointing occurred between the third and fourth cervical through the transverse foramen of the cervical verte- vertebrae. brae and they are relatively protected from external Death from hanging may be caused in one of three compressive forces. However, flow through the verte- ways: 1) direct neurological injury; 2) mechanical con- bral arteries may be compromised during extreme striction of the neck structures, principally arteriove- rotation or flexion. Venous drainage of the head and nous or airway compression; or 3) as a neck is via the internal and external jugular systems result of stimulation of vasoactive centres in the great and the venous plexuses of the spinal cord and col- vessels. from obstruction of the airway is umn. The jugular system is readily compressed by an likely the major cause of suicidal hanging. Although externally applied force. Venous compression is likely fractures and dislocations of the upper cervical spine an important factor in non-judicial hanging. It occurs and resultant cord injury or disruption are common in with low applied forces and results in stagnant cerebral judicial hanging, they are uncommon in suicidal hang- . This predisposes to a loss of consciousness, ings. Survivors of hanging are not uncommon. decreased neck muscle tone and subsequent compres- However, because anaesthetists may be called upon to sion of the arteries and airway. assess and provide care to these patients, a review of The hyoid bone and the superior cornua of the thy- the relevant anatomy and pathophysiology is offered roid are linked by the thyrohyoid ligament. One or along with a discussion of some early management both structures may be fractured with externally issues. applied forces and the ligamentous linkage may con- tribute to fractures or injuries to the adjacent struc- Anatomy ture. 1 Fractures of the thyroid cartilage and hyoid The principle arterial supply to the head and brain is bone are common, occurring in about 50% and 20% via the carotid arteries. (Figure 1) They are separated of hanging suicides, respectively. 2 These injuries are from the anterolateral surface of the neck only by the more commonly described in victims of manual stran- sternomastoid muscles, deep cervical fascia, platysma gulation than after suicidal hanging. They are also and skin. Posteriorly, they rest on the transverse more common in older patients who are more likely to processes of the fourth to sixth cervical vertebrae, have an ankylosed hyoid bone or an ossified thyroid against which they may be easily compressed. Traction cartilage. Severe injury to deep neck structures is not injuries of the carotid arteries can occur at the level of common but has been described in the forensic litera- the ligature in about 5% of hanging victims) Bleeding ture. However, because these observations are made into the vessel wall or intimal disruption occurs, com- on postmortem assessments, the level of reported promising flow through the vessel. These injuries are injury may be more extreme than that expected in sur- Kaki et al.: RESPIILkTORY CARE AFTER HANGING 447 vivors. Most airway injuries are minor: life-threatening oedema. During quiet respiration, intrapleural inspira- airway injuries in survivors of suicidal hanging are tory pressures range from -2 to -5 cm H20 but may uncommon. Injuries to the trache~ are also rare. 2 increase to -100 cm H20 during airway obstruction. These extreme negative intrapleural pressures increase The Pathophysiological Consequences of Hanging venous return, pulmonary blood volume and pul- In survivors of strangulation injury, haemorrhage may monary capillary hydrostatic pressures while lowering be considerable irL the area of the neck subjected to lig- interstitial hydrostatic pressures, thus increasing the ature forces. Aphonia, hoarseness or occur as a hydrostatic gradient across the capillary membrane,s result of traumatic oedema of the larynx and supraglot- The increased venous return to the right heart also tic tissues. Pulmonary complications including pul- decreases left ventricular compliance via the mechanism monary oedema and bronchopneumonia are implicated ofventricular interdependence, resulting in elevated left in most in-hospital deaths. The pulmonary oedema may ventricular end-diastolic and pulmonary microvascular be from a centri-neurogenic origin or secondary to neg- hydrostatic pressures. These processes also favour the ative intrathoracic pressures generated as the victim formation of pulmonary oedema. Although the nega- attempts inspiration through an obstructed airway. The tive intrapleural pressure is the principal pathological initial phase of neurogenic pulmonary oedema results event in the development of pulmonary oedema associ- from a centrally mediated, massive, sympathetic dis- ated with upper airway obstruction, hypoxia and the charge,s This discharge produces intense, generalised, resulting hyperadrenergic state also contribute to its but transient, vasoconstriction with a resultant shift of development. The hypoxia-induced hyperadrenergic blood from the high-resistance systemic to the low- state causes translocation of blood from the systemic to resistance pulmonary circulation. Pronounced increases the pulmonary circulation and art increase in both pul- ha the pulmonary vascular pressures and blood volume monary vascular resistance and pulmonary capillary per- then produce pulraonary oedema because of the hydro- meability.6 Hanging represents a fixed airway static effect of the: increased pulmonary capillary pres- obstruction (as opposed to a dynamic obstruction) and sure. In addition, the intense hypoxic pulmonary pulmonary oedema would be expected soon ,after vasoconstriction increases permeability both by increas- removal of the ligature and relief of the obstruction. ing intravascular pressures as well as by disrupting the It is likely that the prognosis for the patient with permeability barrier. Neurogenic pulmonary oedema is negative pressure pulmonary oedema after strangula- often recognized after devastating and usually lethal tion injury is not as grave as that for the patient with brain injury, s As such, it is a poor prognostic factor after neurogenic pulmonary oedema. Greater brain injury is a neurological insult. Fishman described two cases of implied in the context of neurogenic oedema and this adult respiratory distress syndrome (ARDS) following would be the major prognostic factor determining the attempted suicide by hanging.4 Both had bilateral pul- ultimate outcome. Negative pressure oedema may monary oedema ~aad one was further complicated by result from transient airway obstruction and, barring pulmonary aspiration. Fishman attributed the pul- brain injury, resolution and recovery would be expect- monary oedema to a central neurogenic mechanism. ed. It is difficult, if not impossible, to determine ini- The patients were managed with tracheal intubation tially the aetiology of pulmonary oedema in survivors and positive pressure ventilation: both survived without of strangulation injury although good neurological neurological deficits. recovery implies a brief episode of obstruction and The original report of postobstructive pulmonary negative pressure as the cause. The good outcomes oedema included cases of upper airway obstruction due achieved by Fishman's patients favours the diagnosis to turnout, strangldation, and near-hanging,s The ini- of postobstructive rather than neurogenic pulmonary flaring event in post-obstructive (negative pressure) oedema as was originally postulated. pulmonary oedema is the markedly negative intrapleur- al pressure generated by a forceful inspiratory effort The Neurological Sequelae of Hanging against an obstructed extrathoracic airway. The inci- Neurological sequelae are the most important after- dence of pulmonary oedema associated with airway math of strangulation. Although initial neurological obstruction has been estimated at 11% in adults requir- assessment is of little prognostic value for the individual ing active airway intervention for acute airway obstruc- patient, the cohort of victims who arrive at hospital with tion of varying aetiology.6 The pathogenesis of absent or agonal respiration, absent vital signs or failed pulmonary oederna associated with upper airway initial resuscitation have a poor prognosis. Survivors of obstruction is rnultifactorial. Markedly negative hanging have probably suffered mixed ischaemic- intrapleural pressure alone can result in pulmonary hypoxia rather than simply hypoxia. 7 Intracranial 448 CANADIAN JOURNAL OF ANAESTHESIA

pressure (ICP) may be elevated and clinical interven- vey involved only a small number of patients and it is tions directed at reducing elevated ICP are warranted. possible that a larger review would have yielded a Delayed neurological sequelae are rare after strangula- higher incidence of severe injury. If we were to base tion. 1,s When they occur, they follow one of three pat- our conclusions on our findings alone, we could only terns: 1) the comatose patient, who improves slightly, be confident that the likelihood of a clinically impor- then deteriorates and dies; 2) the patient who appears tant airway injury was not greater than about 18%.1~ to make a considerable recovery, only to progress to an There was a note in one chart reporting incomplete irreversible herniation syndrome and die; and 3) the subluxation of the first on the second cervical verte- patient who appears to recover completely, then devel- brae, but with no instability. Interestingly, there was ops a delayed encephalopathy and dies. no radiographic documentation of this injury in the chart and no radiographs were available for review. The Ottawa Experience The patient was treated with a collar and discharged An automated, computer search of the medical records for follow-up at the referring institution. The nature of the University of Ottawa adult teaching hospitals for of the spinal injury was not fully elucidated after the the 1984-1994 was carried out. Charts of all patients review of the patient's chart. who survived hanging to be admitted to the hospitals Four patients died; all had required cardiopul- were identified, retrieved and reviewed by the authors. monary resuscitation at the scene. Four were left with Seventeen charts were reviewed; all were suicidal sus- severe neurological and cognitive impairment: all were pensions. Consistent with Canadian statistics regarding comatose and their tracheas were intubated on arrival. suicidal hanging,9 the majority (16 of 17, 94%) of the Four patients recovered but had persistent mild to victims were men <30 yr (average age 31 • 13 yr). moderate cognitive impairment: all had been Thirteen patients were persistently unconscious at dis- comatose on arrival, responding to deep pain only. covery and six of these received cardiopulmonary resus- Five patients recovered fully. Only one of our 13 citation at the scene. These 13 patients remained patients (8%) with poor initial neurological function comatose on presentation to hospital. Two patients made a full recovery, although three (23%) were left with impaired consciousness at the scene were in a sim- with only mild cognitive impairment. ilar condition at presentation to hospital and two patients, fully conscious at the scene, were described as Management Issues alert and oriented in the emergency room. Absent or agonal respiration, absent heartbeat or the Fourteen patients (82%) had their tracheas intubat- need for resuscitation in a patient following a hanging, ed, most at the referring hospital. Five patients trader- either at the scene or in the emergency room carries a went uneventful blind nasal intubation and no airway poor prognosis. However, the patient's neurological features were assessed. The tracheas of the remaining condition may improve markedly from that seen at pre- nine patients were intubated with direct laryngoscopy. sentation and aggressive resuscitation of hanging sur- The notes describing the tracheal intubations were vivors should be instituted immediately regardless of reviewed and revealed no intubation difficulty or the initial neurological findings. A primary injury survey unusual findings at laryngoscopy. Reports of chest should be carried out for other self-inflicted injuries and radiographs were reviewed for all patients. Two a toxicology screen done to test for drug ingestion. patients had dense bilateral pulmonary infiltrates con- Although spinal injury is not common, it must be ruled sistent with either pulmonary oedema or massive aspi- out. The neck should be stabilized at the scene and ration. However, their clinical courses were more immobilization maintained until integrity of the spinal consistent with pulmonary oedema than massive aspi- column is confirmed. Supplemental oxygen should be ration, with physical and radiological resolution over provided and an immediate assessment of the adequacy the next 24 hr. One patient had radiographic evidence of the airway as well as of both ventilation and oxy- of right middle and lower lobe aspirations and one had genation needs to be made. Appropriate respiratory diffuse bilateral atelectatic changes. On soft tissue cer- management should be instituted, including tracheal vical radiographs, two patients had minor soft tissue intubation and mechanical ventilation with positive swelling at the hyoid or laryngeal; one had a small end-expiratory pressure, l Intubation should be carried haematoma at the hyoid level and one had a non- out in patients who arrive requiting cardiopulmonary displaced fracture through the thyroid cartilage. We resuscitation, in the presence of a compromised airway, had anticipated a higher incidence of more severe air- or if neurological compromise is evident. If the patient way injuries. In fact, only minor injuries with little is haemodynamically stable, consideration can be given impact on airway management were found. Our sur- to the use of intravenous opioids, induction agents or Kald et al.: RESPIRATORY CARE AFTER HANGING 449 lidocaine to reduce the hyperdynamic and ICP response 2. Which of the following statements about the to intubation. "/'he technique of intubation should blood supply of the head and brain is true? ensure rapid control of the airway while limiting cervi- a) the carotid arteries rest posteriorly on the cal spinal movement. In most practitioner's hands, spinous processes of the cervical vertebrae. direct laryngoscopy with in-line immobilization meets b) the vertebral arteries are relatively protected these criteria. Mechanical ventilation with positive end during hanging. expiratory presstu:e (PEEP) is recommended for venti- c) the venous drainage is resistant to compression. latory management of patients in whom adequate oxy- d) the jugular system provides the only venous genation cannot 'be maintained despite a patent upper drainage of the head. airway and supplemental oxygenation. 3. All of the following are true statements about the The treatment: of brain oedema is both controver- pathogenesis of negative pressure pulmonary sial and beyond the scope of this article and the inter- oedema except one. State the exception. ested reader is referred to other reviews for an a) increased venous return results in reduction assessment of the current literature. H-s Diuretics are of left ventricular compliance. indicated in the presence of pulmonary oedema irre- b) increased adrenergic tone is associated with an spective of the aefiology. Once the patient's condition increase in pulmonary capillary permeability. is stabilized, they should be transferred to an intensive c) negative intrapleural pressures can result in care setting. Further care will be determined by repeat an increase in the interstitial hydrostatic neurological asse,isments. pressure. d) intrapleural inspiratory pressure may increase Sunarnary to -50 cm H20 during airway obstruction. Survivors of strangulation injury are uncommon. 4. Which of the following statements regarding Laryngo-tracheal injuries are reportedly common and victims of hanging is true? spinal injuries are: not rare after strangulation injury a) neurological complications are implicated in but most assessments have been made after post- most in-hospital deaths. mortem examination of victims) From our review, it b) severe laryngotracheal injuries are common appears that simi]!ar injuries in survivors, which may findings in survivors. have an impact on airway management are uncom- c) hanging is the most common form of stran- mon. However, there is inadequate information on gulation. this topic and more data are needed before a final con- d) pulmonary oedema is always of neurogenic clusion can be drawn. Poor neurological condition at origin. presentation does not necessarily predict poor neuro- logical outcome although the two are associated. Early 5. All of the following may be associated with and aggressive intervention to optimize brain perfu- strangulation injury with one exception. State sion and oxygenation is warranted irrespective of the the exception. initial neurological condition. a) delayed encephalopathy is a complication of strangulation injury. b) cardiac arrest may occur secondary to Self-assessment Questionnaire increased vagal stimulation. For each of the following questions select the one best c) traction injury of the carotid arteries occurs answer. above the level of the ligature. d) fracture of the thyroid cartilage is more com- 1. The true statement concerning mechanisms of mon among elderly patients. injury or deal:h following hanging is: a) fracture of the cervical spine is the usual 6. The following are recommended early manage- cause of death. ment interventions in hanging survivors with b) death can be caused by mechanical compres- one exception. State the exception. sion of the airway. a) a toxicology screen should be done. c) the "hangman's fracture" described the dis- b) an immediate airway assessment should be done. jointing o:f the third and fourth cervical ver- c) direct laryngoscopy can be performed even tebrae. in the presence of severe airway injury. d) asphyxiation is a rare cause of death in judi- d) diuretics are routinely indicated in the pres- cial hanging. ence of abnormal chest x-ray findings. 450 CANADIAN JOURNAL OF ANAESTHESIA

7. Which of the following statements regarding References delayed neurological sequelae is true? 1 Iserson KK Strangulation: a review offigature, manual, a) they are the most important sequelae in sur- and postural neck compression injuries. Ann Emerg vivors of strangulation. Med 1984; 13: 179-85. b) poor initial neurological findings are indica- 2 Polron C], Gee DJ. The Essentials of Forensic Medicine, tive of a poor prognosis. 3rd ed. New York: Pergammon Press, 1973: 371-439. c) survivors of hanging typically suffer a pure 3 Theodore], Robin El). Pathogenesis of neurogenic pul- hypoxic brain insult. monary oedema. Lancet 1975; 2: 749-51. d) if the victim is conscious and alert at the scene, there is no need for hospital admission. 4 Fishman CM, Goldstein MS, Gardner LB. Suicidal hanging. An association with the adult respiratory dis- 8. Which of the following statements regarding tress syndrome. Chest 1977; 71: 225-7. suicidal hanging is true? 5 Timby], Reed C, Zeilender S, Glauser FL. "Mechanical" a) venous compression is an important early causes of . Chest 1990; 98: 973-9. event. 6 Lang'SA, Duncan PG, Shephard DAE, Ha HC. b) loss of consciousness generally results from Pulmonary oedema associated with airway obstruction. compression of the arterial tree. Can J Anaesth 1990; 37: 210-8. c) injury to the spinal cord is common. d) a drop of at least two metres is needed to 7 Senter H], WolfA, Wagner FCJr. Intracranial pressure produce strangulation. in nontraumatic ischemic and hypoxic cerebral insults. J Neurosurg 1981; 54: 489-93. 9. Regarding the early management of survivors of 8 Dooling EC, Richardson EP. Delayed encephalopathy hanging, the following statements are true with after strangling. Arch Neurol 1976; 33: 196-9. one exception. State the exception. 9 Mortality - Summary List of Causes, 1991. Canadian a) the need for resuscitation in an apnoeic Centre for Health Information, Statistics Canada, patient carries a poor prognosis. 1994. b) tracheal intubation should be performed only in the presence of poor ventilation. 10 Hanley]A, Lippman-HandA. If nothing goes wrong, c) once the patient is stabilized, he should be is everything all right? Interpreting zero numerators. transferred to the intensive care unit. JAMA 1983; 249: 1743-5. d) glucose containing solutions should be 11 Mayberg TS, Lain AM. Management of central nervous avoided in the presence of brain injuries. system trauma. Current Opinion in Anaesthesiolgy 1993; 6: 764-71. 10. The following statements about neurogenic pul- 12 Lain AM, Winn HR, CuUen BF, Sundling N. monary oedema are true with one exception. Hyperglycemia and neurological outcome in patients State the exception. with head iniury. J Neurosurg 1991; 75: 545-51. a) the initial phase results from a centrally mediated sympathetic discharge. 13 SieberFE, Traystman RJ. Special issues: glucose and b) it occurs after devastating brain injury. the brain. Crit Care Med 1992; 20: 104-14. c) increased hydrostatic pressures result in pul- 14 Asgeirsson B, Griinde PO, Nordsrrtm CH. A new thera- monary oedema. py of post-trauma brain oedema based on baemody- d) early, aggressive intervention results in an namic principles for brain volume regulation. Intensive improved outcome. Care Med 1994; 20; 260-7. 15 Tietjen CS, Hum PD, UlatowskiJA, Kitsch JR. Answers Treatment modalities for hypertensive patients with 1 2 3 4 5 6 7 8 9 10 intracranial pathology: options and risks. Crit Care b b c c c d a a b d Med 1996; 24: 311-22.