Effect of Nitrous Oxide Use on Long-term Neurologic and Neuropsychological Outcome in Patients Who Received Temporary Proximal Artery Occlusion during Cerebral Aneurysm Clipping Surgery (original) (raw)
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Anesthesiology, 2008
Background Laboratory studies suggest that nitrous oxide augments brain injury after ischemia or hypoxia. The authors examined the relation between nitrous oxide use and outcomes using data from the Intraoperative Hypothermia for Aneurysm Surgery Trial. Methods The Intraoperative Hypothermia for Aneurysm Surgery Trial was a prospective randomized study of the impact of intraoperative hypothermia (temperature = 33 degrees C) versus normothermia (temperature = 36.5 degrees C) in patients with aneurysmal subarachnoid hemorrhage undergoing surgical clipping. Anesthesia was dictated by a limited-options protocol with the use of nitrous oxide determined by individual anesthesiologists. All patients were assessed daily for 14 days after surgery or until hospital discharge. Neurologic and neuropsychological testing were conducted at 3 months after surgery. Outcome data were analyzed via both univariate tests and multivariate logistic regression analysis correcting for factors thought to inf...
British Journal of Anaesthesia, 2006
Background. Postoperative delirium and cognitive decline are common in elderly surgical patients after non-cardiac surgery. Despite this prevalence and clinical importance, no specific aetiological factor has been identified for postoperative delirium and cognitive decline. In experimental setting in a rat model, nitrous oxide (N 2 O) produces neurotoxic effect at high concentrations and in an age-dependent manner. Whether this neurotoxic response may be observed clinically has not been previously determined. We hypothesized that in the elderly patients undergoing non-cardiac surgery, exposure to N 2 O resulted in an increased incidence of postoperative delirium than would be expected for patients not receiving N 2 O.
Avoidance of Nitrous Oxide for Patients Undergoing Major Surgery
Anesthesiology, 2007
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Anaesthesia, 2005
The role of vascular tone in determining cerebral perfusion pressure is increasingly being appreciated. It has been suggested that zero flow pressure, the arterial pressure at which blood flow ceases, represents the effective downstream pressure of the cerebral circulation. Nitrous oxide is a cerebral vasodilator and may therefore decrease zero flow pressure and increase cerebral perfusion pressure. However, these effects may be opposed by the increase in intracranial blood volume produced by cerebral vasodilation. We studied eight healthy volunteers at normocapnia and studied the effects of the inhalation of nitrous oxide 50% on estimated cerebral perfusion pressure and zero flow pressure using transcranial Doppler ultrasonography. We found that nitrous oxide 50% significantly increased estimated cerebral perfusion pressure (p = 0.03), whilst decreasing zero flow pressure (p = 0.01). These results suggest that the vasomotor effects of nitrous oxide predominate in determining the effective downstream pressure of the cerebral circulation in healthy individuals.
Neurology India, 2011
Background: Neuroanesthesiologists are a highly biased group; so far the use of nitrous oxide in their patient population is concerned. We hypothesized that any adverse consequence with use of nitrous oxide should affect the patient so as to prolong his/her stay in the hospital. The primary aim of this preliminary trial was to evaluate if avoidance of nitrous oxide could decrease the duration of Intensive Care Unit (ICU) and hospital stay after elective surgery for supratentorial tumors. Patients and Methods: A total of 116 consecutive patients posted for elective craniotomy for various supratentorial tumors were enrolled between April 2008 and November 2009. Patients were randomly divided into Group I: Nitrous oxide-Isoflurane anesthesia (Nitrous oxide-based group) and Group II-Isoflurane anesthesia (Nitrous oxide-free group). Standard anesthesia protocol was followed for all the patients. Patients were assessed till discharge from hospital. Results: The median duration of ICU stay in the nitrous group and the nitrous-free group was 1 (1-11 days) day and 1 (1-3 days) day respectively (P = 0.67), whereas the mean duration of hospital stay in the nitrous group was 4 (2-16) days and the nitrous free group was 3 (2-9) days (P = 0.06). The postoperative complications in the two groups were comparable. Conclusion: From this preliminary study with a low statistical power, it appears that avoidance of nitrous oxide in one's practice may not affect the outcome in the neurosurgical patients. Further large systemic trials are needed to address this issue.