Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jul 1993
Comparative StudyAirway pressure monitoring as an aid in the diagnosis of air embolism.
We designed a prospective study to compare the validity of airway pressure (AWP) monitoring with that of end-tidal CO2 (ETCO2) monitoring for early detection of air embolism. Subjects included 76 patients of both sexes who underwent neurosurgery in the sitting position. Anesthesia was maintained with O2, N2O, narcotics, pancuronium, and intermittent positive pressure ventilation (IPPV). ⋯ Murmur was noted in four patients and air aspiration in six patients. Only six patients of the 16 had an increase in AWP along with the decrease in ETCO2. We conclude that AWP monitoring is neither a sensitive nor reliable indicator of air embolism.
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J Neurosurg Anesthesiol · Apr 1993
Neurosurgical intensive care unit organization and function: an American experience.
This article describes the organization and function of a university-based neurosurgical intensive care unit. The unit's success has been based in part on its physical structure and in larger part on its organization. ⋯ This type of approach promotes teamwork and fosters mutual respect among the team. It also improves patient care and, frequently, outcome.
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J Neurosurg Anesthesiol · Oct 1992
End-tidal carbon dioxide as an indicator of arterial carbon dioxide in neurointensive care patients.
The relationship between the arterial partial pressure of carbon dioxide (Paco2) and the end-tidal carbon dioxide partial pressure (PEtco2) was evaluated in 11 critically ill adult neurointensive care patients during mechanical ventilation. It was hypothesized that the Paco2 to PEtco2 gradient, or P(a-Et)co2, was maintained and that PEtco2 can be used to determine Paco2 accurately in these patients. After approval by the Clinical Investigations Committee, when clinically indicated arterial blood gases (with Paco2) were measured, the PEtco2 was determined from the capnograph (Hewlett Packard 78520A infrared capnometer). ⋯ The direction of Paco2 change was inaccurately predicted by PEtco2 changes in 31.9% of measurements. PEtco2 does not provide a stable reflection of Paco2 in all neurointensive care patients. Arterial blood gases cannot be eliminated when monitoring respiratory acid-base balance in mechanically ventilated neurointensive care patients.
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J Neurosurg Anesthesiol · Jul 1992
Cerebral blood flow at constant cerebral perfusion pressure but changing arterial and intracranial pressure: relationship to autoregulation.
Therapeutic agents for reducing raised intracranial pressure (ICP) may do so at the expense of reduced mean arterial pressure (MAP). As a consequence, cerebral perfusion pressure (CPP) = (MAP - ICP) may not improve. It is unknown whether the level of MAP alters cerebral blood flow (CBF) when MAP and ICP change in parallel so that CPP remains constant. ⋯ At a CPP of 40 mm Hg, CBF showed a linear correlation with blood pressure (BP) (r = 0.57, p <0.05). These results demonstrate that when autoregulation is impaired, there is a functional difference between autoregulating and nonautoregulating cerebral vessels despite similar MAP and CPP. These results also show that at a CPP of 40 mm Hg when autoregulation is impaired, CBF depends more on arterial driving pressure than on CPP.