Nocturnal oxygenation during patient-controlled analgesia.

UNLABELLED: Patient-controlled analgesia (PCA) has become a standard modality for the management of postoperative pain, although anecdotal reports of excessive sedation and respiratory depression impugn its safety. To study the prevalence and severity of nocturnal hypoxemia, we measured arterial oxygen saturation (SpO2) continuously overnight in 32 postoperative patients who were receiving morphine via PCA. To evaluate the potential benefit of providing concurrent supplemental oxygen, the patients breathed oxygen-enriched air the night of surgery and room air the next night. Patients experienced more pain and consumed twice as much morphine the first night. However, breathing supplemental oxygen that night, the nocturnal mean SpO2 was 99%+/-1%, 94%+/-4% (P<0.001), and only four patients had periods of hemoglobin desaturation <90%. In contrast, breathing room air the subsequent night, the mean SpO2 was lower (94%+/-4%; P<0.001), and hypoxemia occurred more frequently and was more severe: 18 patients experienced episodes of SpO2 <90%, 7 patients experienced episodes of SpO2 <80%, and 3 patients experienced episodes of SpO2 <70%. One patient required resuscitation for profound bradypnea and cyanosis, but none suffered permanent sequelae. We conclude that when postoperative patients use PCA at night, hypoxemia can be substantial and oxygenation can be improved by providing supplemental oxygen. IMPLICATIONS: Oxygen saturation was measured postoperatively in patients using morphine patient-controlled analgesia. Substantial nocturnal hypoxemia occurred in half of the patients while they breathed room air. The severity of the hypoxemia was reduced when patients received supplemental oxygen.

Incidental conversion to sinus rhythm from atrial fibrillation during external jugular venous catheterization.

External jugular venous (EJV) catheterization is a frequent method of gaining central venous access because of its low complication rate. We describe a unique experience during EJV in which a patient with chronic atrial fibrillation converted suddenly to a sustained sinus rhythm without perioperative complication from this event. Our experience depicts a rare consequence of the central catheter placement and we, as anesthesiologists, should be aware of its potential occurrence in the operating room.

Epistaxis, medical history, and the nasopulmonary reflex: what is clinically relevant?

Posterior epistaxis and its management are associated with increased morbidity and sudden death. A "nasopulmonary reflex," changes in pulmonary function induced by packing, has been postulated to cause hypoxia and lead to the reported morbidities. However, no study has followed patients prospectively to associate complications with oxygen status. Continuous pulse oximetry monitoring of 19 patients hospitalized with posterior packing was undertaken to document the incidence and extent of oxygen desaturation, and to correlate complications with O2 status and historical factors. A further aim was to clarify the clinical relevance of the nasopulmonary reflex. In 1200 hours of monitoring, desaturations to less than 90% were observed on only two occasions: one self-limited episode in an actively bleeding patient and one major hypoxic event with respiratory arrest in an alcoholic patient under sedation for delirium tremens. Complications, while uncommon, were more appropriately ascribed to rebleeding or underlying medical problems than to primary O2 status. The nasopulmonary reflex, as previously described in terms of a primary drop in O2, therefore seems clinically irrelevant. Early surgery for posterior epistaxis is not warranted on the basis of maintenance of adequate oxygenation alone.

Ventilatory complications of carbon dioxide laser laryngeal surgery.

STUDY OBJECTIVE: To evaluate complications associated with ventilatory techniques accompanying endolaryngeal carbon dioxide laser surgery. DESIGN: Retrospective survey of the Society of Academic Anesthesia Chairmen. SETTING: Operating room at an urban medical center. PATIENTS: Data from 15,701 patients were analyzed. MEASUREMENTS AND MAIN RESULTS: Twenty-six percent of patients were ventilated with Venturi jet ventilation and the rest through an endotracheal tube. Reported complications were classified as ventilation related and ventilation unrelated, as well as by severity. A total of 49 complications occurred in the Venturi jet group (1.2%). Of these complications, 24 were ventilation related (0.58%) and 18 were serious or life threatening (0.43%). There were no deaths in this group. Ventilation through an endotracheal tube was associated with a lower frequency of overall complications (0.36%), ventilation-related complications (0.15%), serious or life-threatening complications (0.15%), and serious or life-threatening ventilation-related complications (0.11%) (p less than 0.001). However, there were eight airway fires in this latter group, one resulting in a fatality. CONCLUSIONS: No clear choice of ventilatory technique is supported by this survey, but teamwork and experience give the best results.