Tension Pneumothorax During Apnea Testing for the Determination of Brain Death

The apnea test (AT) is considered as the ‘condition sinequa non’ by most of the intesivists for determiningbrain death (BD) as it provides an importantinformation for a definitive loss of brainstem function.It is the most difficult clinical test in BD protocols andis also potentially harmful and lengthy. The possiblecomplications of this test include severe decrease inblood pressure, pneumothorax, excessive CO2 retention,hypoxia, acidosis, and cardiac arrhythmia or asystole.It is important to abort the test in the setting of any ofthe above mentioned complication, which willcompromise BD diagnosis. It is important to ensurethat certain prerequisites are satisfied before the AT iscarried out. These include body temperature 32°C ormore, normal PO2 or preoxygenation to obtain anarterial PO2 ≥ 200 mmHg, arterial PCO2 orPaCO2 normal or above 40 mmH, blood pH normal orin the low basic range, pretest systolic blood pressureof at least 90 mmHg, Euvolemia or a positive fluidbalance during the previous 6 hours, no drug that canparalyze the respiratory muscles. If continuous orintermittent oxygen supply is preceded by decreasingnitrogen levels of blood gases, high PaO2 levels can bemaintained for very long periods of time.Preoxygenation removes alveolar nitrogen stores andhelps oxygen transport. There are several techniquesfor ascertaining that there is sufficient oxygenationduring AT .1-5