Hrev_master [Emergency Care Journal 2016; 12:5597] [page 51] Survivor from asphyxiation due to helium inhalation Massimiliano Etteri, Andrea Bellone, Morena Vella, Eleonora Capiaghi, Luca Motta, Ilaria Malfasi Emergency Department, Sant’Anna Hospital, San Fermo della Battaglia (CO), Italy Abstract In this rare case report we describe a 27- year-old white man survived to suicide by asphyxiation using the so-called suicide bag (or exit bag) filled with helium supplied through a plastic tube. He had no previous psy- chiatric or organic illnesses. At the time of presentation to our Emergency Department he was awake and reported severe dyspnea with a clinical pattern of acute respiratory failure. Imaging studies showed pulmonary edema and the patient was treated with non-invasive ven- tilation in Intensive Care Unit. After 15 days the patient was discharged from hospital in optimal conditions. These rare cases of sur- vivor might suggest the possible causes of death from inhaling helium. Case Report A 27-year-old male student was rescued at home by his father: he was found to be uncounscious with so-called suicide bag (or exit bag) filled with helium supplied through a plastic tube. Immediately he removed the bag (not really narrow neck) from the head and called the emergency number. When the ambulance arrived he was found with prompt resumption of breathing and slow recovery of consciousness with peripheral cyanosis, pulse rate was 130/minute and blood pressure 160/90 mmHg. On arrival at the Emergency Department he was conscious with hemodynamic stability, the respiratory rate was 35/min, pheripheral pulse oxymetry revealed SpO2 of 80% in air. Past medical his- tory was negative. Thoracic fine crepitations were auscultated on both sides. Heart sound was normal. Hemogasanalysis showed a severe respiratory failure with PaO2/FiO2 value of 120. Electrocardiogram revealed non-abnormalities except sinus tachycardia. We performed a chest X-ray and a bedside lung ultrasound with convex probe 5 MHz that revealed a bilateral B- pattern typical of interstitial syndrome, mainly due to acute pulmonary edema. Inferior vena cava and heart contractility were normal (stud- ied with a cardiac phased array probe 2.5 MHz). Moreover it was performed a thoracic CT scan which confirmed the diagnosis of bilateral pulmonary edema that was bilateral, symmetric, ground-glass like, and not involv- ing the anterior areas of the chest. A non-invasive ventilation (NIV) with full- face mask was applied. Ventilatory settings were as follows: FiO2 50%, PEEP 10 cm of H2O, PS 5 cm of H2O. Blood test was normal except for a slight increase of troponins. He was transferred to the Intensive Care Unit. On the three day of hospitalization patient was successfully weaned off the non invasive ventilator: pulse rate was 80/minute and blood pressure 120/70 mm of Hg, the respi- ratory rate was 15/min, SpO2 of 98%. Then he was transferred to the pulmonology ward. The patient remained asymptomatic over the next 10 days. Blood test was normal. Chest was clinically clear. After being subjected to a psychiatric evaluation, he was discharged from the hospital. Discussion Helium is one of inert gases causing physi- cal asphyxiation, whose excess content in the breathing atmosphere reduces the partial pressure of oxygen and may be fatal after short-term exposure. When breathing a mix- ture of an inert gas (helium, nitrogen, argon) with a small amount of oxygen, with the possi- bility of exhaling carbon dioxide, no warning signs characteristic of suffocation are per- ceived by the subject. Freedom from discomfort and pain, effectiveness, rapid effect and rela- tively easy availability of required accessories have resulted in the use of inert gases for sui- cidal purposes. This case report a suicide attempt by using a kit consisting of the so- called suicide bag filled with helium supplied through a plastic tube.1-3 This rare case sur- vived shows the pathophysiology of pulmonary edema from pure severe hypoxia at sea level because helium is an inert gas that only reduces the partial pressure of oxygen. The process of hypoxic pulmonary vasoconstriction (HPV) was first identified in 1894, as a rise in pulmonary arterial pressure upon asphyxia.4 Alveolar hypoxia leads to an adaptative vaso- motor response in the form of hypoxic pul- monary vasoconstriction.5 The pulmonary cap- illary pressure increases as a result of HPV, which occurs mainly in smaller pulmonary arteries. As a result of the constriction of small pulmonary arteries, blood gets diverted away, causing elevated blood flow and raising the pressure, which consequently leads an the increase in capillary permeability mainly in areas more perfused:6 our pulmonary edema was bilateral, symmetric, ground-glass like, and not involving the anterior areas of the chest probably due to supine position of the patient. Another mechanism involved in pulmonary edema is a sympathetic activation: an intense activation of the sympathetic nervous system and the release of catecholamines are the prime contributors to exaggerated HPV.7 Furthermore, severe hypoxia causes cerebral edema and elevation in intracranial pressure (ICP). Elevated ICP levels correlate with increased levels of extravascular lung water (EVLW) playing an important role in the patho- genesis of neurogenic pulmonary edema (NPE).8 Conclusions To conclude, in this case we describe the beginning, evolution and resolution of a non- cardiogenic pulmonary edema due to asphyxi- ation caused by helium inhalation. Extreme hypoxia and sympathetic activation are the main causes of the development of pulmonary edema with high mortality and only autopsy cases post-mortem. Instead, in this rare case of surviving we have observed the consequences of an event such as extreme hypoxia that is a reversible process once recognized and proper- ly treated. References 1. Grassberger M, Krauskopf A. Suicidal asphyxiation with helium: report of three cases. Wien Klin Wochenschr 2007;119:323-5. Emergency Care Journal 2016; volume 12:5597 Correspondence: Massimiliano Etteri, Emergency Department, Sant’Anna Hospital, via Ravona 1, 22020 San Fermo della Battaglia (CO), Italy. Tel. +39.02.48703668 - Fax: +39.031.5855853. E-mail: max.etteri@alice.it Key words: Asphyxiation; Helium inhalation; Suicide. Received for publication: 21 October 2015. Accepted for publication: 7 June 2016. This work is licensed under a Creative Commons Attribution 4.0 License (by-nc 4.0). ©Copyright M. Etteri et al., 2016 Licensee PAGEPress, Italy Emergency Care Journal 2016; 12:5597 doi:10.4081/ecj.2016.5597 Non co mmerc ial us e o nly [page 52] [Emergency Care Journal 2016; 12:5597] 2. Schon CA, Ketterer T. Asphyxial suicide by inhalation of helium inside a plastic bag. Am J Forensic Med Pathol 2007;28:364-7. 3. Ogden RD, Wooten RH. Asphyxial suicide with helium and a plastic bag. Am J Forensic Med Pathol 2002;23:234-7. 4. Bradford JR, Dean HP. The pulmonary cir- culation. J Physiol 1894;16:34-158. 5. Archer S, Michelakis E. The mechanism(s) of hypoxc pulmonary vaso- constriction:potassium channels,redox 0(2) sensors, and controversies. News Physiol Sci 2002;17:131-7. 6. Bhagi S, Srivastava S, Singh SB. High-alti- tude pulmonary edema:review. J Occup Health 2014;56:235-43. 7. Rogers FB, Shackford SR, Trevisani GT, et al. Neurogenic pulmonary edema in fatal and nonfatal head injuries. J Trauma 1995;39:860-6. 8. Demling R, Riessen R. Pulmonary dysfunc- tion after cerebral injury. Crit Care Med 1990;18:768-74. Case Report Non co mmerc ial us e o nly