Mr. A is 24 years of age with a history of schizophrenia (Slide 1). He has been living with his parents and has been ill for a few years. Police saw him on the street in a state of crisis and brought him to the emergency room (ER). He was very anxious and his delusions of being in great physical danger had worsened. He reported a history of asthma, but it was noted that his asthma occurred a long time ago and was inactive; however, due to his anxiety, his smoking had increased to where it was continuous. At the time he was brought to the ER, Mr. A was triaged to psychiatry and became agitated in the waiting area; hence, security was called. He was about to be restrained and given an intramuscular dose (IM) of lorazepam, but the psychiatrist noted that he was having trouble breathing and stopped the IM before it was given. The psychiatrist noticed that Mr. A was wheezing, had a rapid respiratory rate of 25/minute, was tachycardic, and sweating. His pulse oximeter measurement was 90% saturated, which is considered low.Mr. A was re-interviewed and reported that he previously had asthma. His parents were contacted and agreed that he had active asthma, had stopped his psychiatric treatment several months ago, and, more recently, stopped his asthma medications when his prescriptions were not refilled ∼1 week prior to this episode. An emergency arterial blood gas showed a pH of acidosis at 7.27; a Po2 of 60 (normal is 80); and a Pco2 of 48 (normal is 40). The Pco2 was of particular concern because if he was retaining CO2, respiratory failure was imminent.
IPPB and hypercapnia in respiratory failure: The effect of different concentrations of inspired oxygen on arterial blood gas tensions
