Survivor by asphyxiation due to helium inhalation

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 psychiatric 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 ventilation in Intensive Care Unit. After 15 days the patient was discharged from hospital in optimal conditions. These rare cases of survivor might suggest the possible causes of death from inhaling helium. Case ReportA 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 history 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 Bpattern typical of interstitial syndrome, mainly due to acute pulmonary edema. Inferior vena cava and heart contractility were normal (studied 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 involving the anterior areas of the chest.A non-invasive ventilation (NIV) with fullface 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 respiratory 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. DiscussionHelium is one of inert gases causing physical 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 m...