Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1990
Randomized Controlled Trial Clinical TrialEffect on outcome of prolonged exposure of patients to nitrous oxide.
Prolonged (several days or repeated) exposure to nitrous oxide (N2O) can cause injury or death. To assess whether relatively prolonged anesthesia with N2O in normal patients might similarly cause untoward effects, we investigated whether the addition of N2O to isoflurane anesthesia caused injury to patients having surgical resection of acoustic neuroma lasting approximately 10 h. Twenty-six patients undergoing surgical resection of acoustic neuroma were randomly assigned to a regimen that included or excluded N2O (50%-60%) during isoflurane anesthesia plus intravenous adjuvants. ⋯ We measured standard clinical variables (blood pressure, heart rate), oxygen saturation, neurologic status, pain, and the incidence and type of morbid outcomes. Exposure to N2O did not increase the incidence of morbid outcomes (including hepatic injury, infection, or hypoxemia), prolong hospitalization, or increase common postoperative complaints such as nausea, vomiting, coughing, or headache. Patients anesthetized with either regimen were equally satisfied with their anesthetic.
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Anesthesia and analgesia · Dec 1990
Randomized Controlled Trial Clinical TrialPostoperative hypoxemia after nonabdominal surgery: a frequent event not caused by nitrous oxide.
We tested whether anesthesia that includes nitrous oxide (N2O) results in the development of intraoperative and postoperative pulmonary complications, including hypoxemia. We also tested whether aging contributes to the development of such complications, particularly when anesthesia includes N2O. We randomly allocated patients having total hip replacements, carotid endarterectomies, or transsphenoidal hypophysectomies (total n = 270) to an anesthetic regimen with and without N2O (stratified within surgical group). ⋯ Hypoxemia (O2 saturation less than 86%) developed in five patients receiving N2O and in one receiving O2. This difference was not significant. Administration of N2O did not decrease postoperative O2 saturation, nor did it alter the incidence of postoperative hypoxemia, cough, or sputum production.
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Anesthesia and analgesia · Dec 1990
Randomized Controlled Trial Clinical TrialNo finding of increased myocardial ischemia during or after carotid endarterectomy under anesthesia with nitrous oxide.
Nitrous oxide (N2O) has been implicated as a cause of myocardial ischemia. We investigated whether substitution of N2O for a portion of the anesthesia supplied by isoflurane increased myocardial ischemia in patients at risk for such ischemia. Seventy patients having carotid endarterectomies (63 patients) or other carotid surgery (seven patients) were prospectively, randomly assigned to an anesthetic regimen that included or excluded N2O. ⋯ By transesophageal echocardiographic or electrocardiographic criteria, 44% of patients given oxygen but only 21% of those given N2O had myocardial ischemia intraoperatively (P = 0.065). Similarly, myocardial infarction, identified by changes in creatine kinase isoenzymes, occurred in only one patient given N2O but in three given oxygen (not significantly different). Thus we found no trend indicating a greater incidence of myocardial ischemia or infarction associated with the use of N2O.
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Anesthesia and analgesia · Dec 1990
Randomized Controlled Trial Clinical TrialNitrous oxide does not impair hepatic function in young or old surgical patients.
We investigated whether anesthesia including nitrous oxide (N2O) caused hepatic injury, and whether any adverse effect of N2O was affected by patient age. One hundred patients having total hip replacements were randomly assigned to a regimen that included or excluded N2O (50%-60%) during regional anesthesia supplemented with isoflurane and intravenous adjuvants. Using postoperative plasma levels of alanine aminotransferase, bilirubin, and alkaline phosphatase 1 and 3 days after surgery as indicators of hepatic impairment, we found no evidence that N2O causes hepatic injury in either young or old patients.
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Anesthesia and analgesia · Dec 1990
Randomized Controlled Trial Clinical TrialNitrous oxide and epinephrine-induced arrhythmias.
We asked whether the sympathomimetic effect of nitrous oxide (N2O) predisposed patients receiving N2O to arrhythmias in response to epinephrine administration. We also asked whether aging contributed to the development of arrhythmias, with or without N2O. One hundred patients having transsphenoidal hypophysectomy were randomly assigned to receive anesthesia including (n = 49) or excluding (n = 51) N2O. ⋯ Both anesthetic groups had a high incidence of postoperative changes in T-wave morphology (46.9% in the N2O group vs 50.9% in the group not given N2O). Aging alone did not affect the incidence of ventricular ectopic beats, isorhythmic AV dissociation, or changes in electrocardiographic morphology, but correlated with the development of ventricular ectopy during N2O anesthesia. We conclude that the use of N2O correlated with a higher incidence of isorhythmic AV dissociation in response to injection of epinephrine with lidocaine.