Prolonged post-hyperventilation apnea in two young adults with hyperventilation syndrome

Abstract

Background: The prognosis of hyperventilation syndrome (HVS) is generally good. However, it is important to proceed with care when treating HVS because cases of death following hyperventilation have been reported. This paper was done to demonstrate the clinical risk of post-hyperventilation apnea (PHA) in patients with HVS.

Case presentation: We treated two patients with HVS who suffered from PHA. The first, a 21-year-old woman, had a maximum duration of PHA of about 3.5 minutes and an oxygen saturation (SpO2) level of 60%. The second patient, a 22-year-old woman, had a maximum duration of PHA of about 3 minutes and an SpO2 level of 66%. Both patients had loss of consciousness and cyanosis. Because there is no widely accepted regimen for treating patients with prolonged PHA related to HVS, we administered artificial ventilation to both patients using a bag mask and both recovered without any after effects.

Conclusion: These cases show that some patients with HVS develop prolonged PHA or severe hypoxia, which has been shown to lead to death in some cases. Proper treatment must be given to patients with HVS who develop PHA to protect against this possibility. If prolonged PHA or severe hypoxemia arises, respiratory assistance using a bag mask must be done immediately.

Figure 1

Clinical course of apnea and HV attacks on fifth day after admission: Patient 1. The patient presented a 3.5-minute episode of apnea after an HV attack with a minimum SpO₂ of 60% and cyanosis of the lips and nail beds. The patient did not exhibit hypoxemia during the HV attack or during normal respiration. X₁ and X₃ represent the apneic starting time. X₂ and X₄ represent the time of the assisted ventilation by bag-mask. X₁X₂ and X₃X₄ are the lengths of the apneic times, which were 3.5 and 2 minutes, respectively. X₁X₂ and X₃X₄ were recorded, but times X_1,X_2, X_3, and X₄ were not recorded correctly. HV: hyperventilation.

Figure 2

Clinical course of apnea and HV attacks about one month after admission: Patient 2. The patient presented a 3-minute episode of apnea after an HV attack with a minimum SpO₂ of 66% and cyanosis of the lips. The patient did not show hypoxemia during the hyperventilation attack or during normal respiration. HV: hyperventilation, I.m.: intramuscular injection.