Background It is not known whether the effects of desflurane on local cerebral glucose utilization (LCGU) and local cerebral blood flow (LCBF) are different from those of other volatile anesthetics. Methods Using the autoradiographic iodoantipyrine and deoxyglucose methods, LCGU, LCBF, and their overall means were measured in 60 Sprague-Dawley rats (10 groups, n = 6 each) during desflurane and isoflurane anesthesia and in conscious controls. Results During anesthesia, mean cerebral glucose utilization was decreased compared with conscious controls: 1 minimum alveolar concentration (MAC) desflurane: -52%; 1 MAC isoflurane: -44%; 2 MAC desflurane: -62%; and 2 MAC isoflurane: -60%. Local analysis showed a reduction of LCGU in the majority of the 40 brain regions analyzed. Mean cerebral blood flow was increased: 1 MAC desflurane: +40%; 1 MAC isoflurane: +43%; 2 MAC desflurane and 2 MAC isoflurane: +70%. LCBF was increased in all brain structures investigated except in the auditory cortex. No significant differences (P < 0.05) could be observed between both anesthetics for mean values of cerebral glucose use and blood flow. Correlation coefficients obtained for the relation between LCGU and LCBF were as follows: controls: 0.95; 1 MAC desflurane: 0.89; 2 MAC desflurane: 0.60; 1 MAC isoflurane: 0.87; and 2 MAC isoflurane: 0.68. Conclusion Differences in the physicochemical properties of desflurane compared with isoflurane are not associated with major differences in the effects of both volatile anesthetics on cerebral glucose utilization, blood flow, and the coupling between LCBF and LCGU.
Intraoperative airway management by anesthesiology providers has evolved over the years to include many specialized devices and techniques that can have tremendous impact on the care of the perioperative critically ill patient. When perioperative patient care issues arise, anesthesiologists and perioperative critical care specialists should both be actively involved in a dialogue regarding many the relevant patient care issues, including any airway and respiratory function problems. Additionally, critical care specialists should be familiar with the use and potential complications of the increasingly diverse airway (and non-airway) tools and devices used by anesthesiologists in the operating room. The authors present a case report of a 66-year-old man who suffered repeated postoperative respiratory failure following an uncomplicated upper extremity orthopedic procedure. The patient developed unexplained, repeated postoperative respiratory failure that necessitated reintubation related to the accidental and unrecognized retention of a plastic tip extender from a Bullard fiber-optic laryngoscope. After transfer to the ICU, the patient continued to have significant respiratory distress requiring aggressive post-extubation noninvasive mechanical ventilation. The cause of this complication was not diagnosed by the anesthesiologist or the intensive care team throughout the course of this patient’s respiratory failure. Ultimately, the patient spontaneously expectorated the tip extender with rapid improvement in his respiratory function. This case highlights the importance of the dialogue that should occur between anesthesiologists and critical care specialists when unexpected and/or unexplained perioperative complications occur.
Dexmedetomidine is a selective α2-agonist, frequently used in perioperative medicine as anesthesia adjunct. The medication carries a Food and Drug Administration pregnancy category C designation and is therefore rarely used for parturients undergoing nonobstetric surgery. We are reporting the use of dexmedetomidine in the anesthetic management of a parturient undergoing minimally invasive unilateral adrenalectomy for pheochromocytoma during the second trimester of pregnancy. Additionally, because of the multiple endocrine neoplasia type 2A constellation with diagnosis of medullary thyroid cancer, the patient underwent a total thyroidectomy 1 week after the adrenalectomy.
Educational research projects are often developed and implemented at a single institution. However, the research project methods and results may not be generalizable and able to be replicated successfully at other institutions. The aim of this study was to investigate the process of replicating an effective educational Objective Structured Clinical Examination (OSCE) event at multiple other institutions.An OSCE event was initially designed and implemented at the primary institution to assess the skill level of junior residents on the performance of basic anesthesia tasks. After the initial implementation, additional institutions were recruited to participate in a replication of this OSCE event at their own institutions. The primary institution provided the OSCE scenarios, assessment tools, rater training, and resident participant instructions. The participating secondary institutions' (n = 4) event managers obtained Institutional Review Board [IRB] approval, developed the event schedule, assigned faculty evaluators, and organized the simulation space at their own medical centers. The events were assessed by the secondary institutions' resident and faculty participants via an anonymous survey regarding the event's content and their perception of its educational value.We replicated a complex educational OSCE event, developed and implemented at 1 institution, at 4 other institutions. Resident participants (n = 60), participating faculty (n = 24), and event directors (n = 4) indicated a high level of appreciation for the OSCE event.Using a structured approach, educational OSCE events can be successfully replicated at multiple institutions. Organization of multi-institutional studies and collaborative efforts is complex. This study illustrates 1 example of how to successfully approach multi-institutional educational projects.
The clinical utility of cross-linked tetrameric hemoglobin solutions is limited by peripheral vasoconstriction thought to be due to scavenging of nitric oxide. In addition, transfusion of crude preparations of hemoglobin polymers can cause arterial hypertension. We tested the hypothesis that eliminating low-molecular-weight components from the polymer solution would prevent extravasation and its associated pressor response. A zero-link polymer of bovine hemoglobin was developed without chemical linkers left between the tetramers. Transfusion of unprocessed preparations of these polymers in rats resulted in appearance of the polymer in the renal hilar lymph. However, eliminating the low-molecular-weight components with a 300-kDa diafiltration resulted in an average hydrodynamic radius of 250 Å and in undetectable levels of polymer in hilar lymph. Exchange transfusion in anesthetized rats and cats and in awake cats produced no increase in arterial pressure. In anesthetized cats, exchange transfusion with an albumin solution reduced hematocrit from 30 to 18%, increased cerebral blood flow, and dilated pial arterioles. In contrast, reducing hematocrit by transfusing the diafiltered polymer did not increase cerebral blood flow as pial arterioles constricted. These results are consistent with the hypothesis that the increase in arterial pressure associated with cell-free hemoglobin transfusion depends on hemoglobin extravasation. Constriction observed in the cerebrovascular bed with a nonextravasating hemoglobin polymer at low hematocrit is presumably a regulatory response to prevent overoxygenation at low blood viscosity.
Introduction: Patients with aneurysmal subarachnoid hemorrhage (aSAH) are at risk for sepsis during their hospitalization; however, it is not clear how this diagnosis may affect the risk of mortality and their length of stay. Hypothesis: The diagnosis of sepsis in patients with aSAH increases mortality and length of stay compared to patients with aSAH who are not diagnosed with sepsis. Methods: The University Healthcare Consortium (UHC) database was queried from 04/2008 to 06/2011 for all patients with primary ICD-9 diagnosis codes of aSAH. Inpatient mortality, ICU length of stay and hospital length of stay for these patients were then compared based on whether they had a secondary diagnosis of sepsis or other related conditions, including septicemia, severe sepsis, and septic shock, during their admission. Results: Using the UHC database, 33849 patients with aSAH were located. Of these patients, approximately 2080 (6.1%) also had a sepsis-related diagnosis. When these aSAH patients were compared to patients with sepsis-related diagnoses, the mortality was increased from 17.9% to 45.3% (p<0.0001), ICU LOS was increased from a mean of 9.6 days to 18.8 days (p<0.0001), and hospital LOS was increased from a mean of 13.4 days to 28.2 days (p<0.0001). Conclusions: Sepsis was associated with a statistically significant increase in mortality, ICU LOS and hospital LOS in patients with aneurysmal SAH. Additional studies are warranted to determine risk factors for the poor outcomes observed in these patients and to determine whether the utilization of specific care measures and bundles may improves these outcomes.
We addressed the question to which extent cerebral blood flow (CBF) is maintained when, in addition to a high blood viscosity (B vis ) arterial oxygen content (Ca O 2 ) is gradually decreased. Ca O 2 was decreased by hemodilution to hematocrits (Hct) of 30, 22, 19, and 15% in two groups. One group received blood replacement (BR) only and served as the control. The second group received an additional high viscosity solution of polyvinylpyrrolidone (BR/PVP). B vis was reduced in the BR group and was doubled in the BR/PVP. Despite different B vis , CBF did not differ between BR and BR/PVP rats at Hct values of 30 and 22%, indicating a complete vascular compensation of the increased B vis at decreased Ca O 2 . At an Hct of 19%, local cerebral blood flow (LCBF) in some brain structures was lower in BR/PVP rats than in BR rats. At the lowest Hct of 15%, LCBF of 15 brain structures and mean CBF were reduced in BR/PVP. The resulting decrease in cerebral oxygen delivery in the BR/PVP group indicates a global loss of vascular compensation. We concluded that vasodilating mechanisms compensated for B vis increases thereby maintaining constant cerebral oxygen delivery. Compensatory mechanisms were exhausted at a Hct of 19% and lower as indicated by the reduction of CBF and cerebral oxygen delivery.
