As clinicians, we often question why some patients respond to naloxone and others do not when opioid-induced ventilatory impairment is suspected. This inexplicability is disconcerting, given the toll of opioid-induced ventilatory impairment–related deaths. Our search for greater understanding, as recently provided in this Journal by van Lemmen et al.,1 is paramount.
As minute ventilation falls under the influence of an opioid, the Pao2 will decline, and the Paco2 will rise.2 This relationship may be estimated in a perfect circumstance (without any contribution from shunt, for example) by the alveolar gas equation.3 A patient affected by opioid-induced ventilatory impairment breathing room air may present with an arterial oxygen saturation of 60% and a Paco2 100 mmHg estimated by the alveolar gas equation.4 Observational studies in human respiratory failure patients note aberrations of consciousness at Paco2 90 mmHg and...
