Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2006
Comparative StudyChromosomal substitution-dependent differences in cardiovascular responses to sodium pentobarbital.
In this study we addressed initial laboratory observations of enhanced cardiovascular sensitivity to sodium pentobarbital (PTB) in normotensive Dahl Salt Sensitive rats (SS) compared to Brown Norway (BN) rats. We also used unique consomic (chromosomal substitution) strains to confirm preliminary observations that such differences were related to chromosome 13. Increasing concentrations of PTB were administered sequentially to SS, BN, and SS strains with BN chromosomal substitutions until the point of cardiovascular collapse. ⋯ In neurally intact preparations, large dose PTB-induced VSM hyperpolarization was 4-5 times greater than the small dose in SS and SS.16BN but not in BN and SS.13BN strains. Denervation eliminated this strain difference. These results suggest that enhanced cardiovascular sensitivity to PTB in SS rats is related to greater hyperpolarization of VSM transmembrane potential in resistance vessels and this effect is associated with chromosome 13.
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Anesthesia and analgesia · Mar 2006
Comparative StudyKetamine attenuates sympathetic activity through mechanisms not mediated by N-methyl-D-aspartate receptors in the isolated spinal cord of neonatal rats.
Ketamine is believed to have sympathomimetic effects, although the central mechanism remains unclear. Using an in vitro splanchnic nerve-spinal cord preparation from neonatal rats, our previous investigations have demonstrated that tonic sympathetic activity is spontaneously generated from the thoracic spinal cord. We designed this study to investigate whether applications of ketamine to the cord would augment sympathetic activity and whether this action was dependent on N-methyl-d-aspartate receptors. ⋯ The 50% inhibitory concentration of ketamine on sympathetic activity was 32 muM. Pretreatment with DL-2-amino-5-phosphonovaleric acid, a selective competitive N-methyl-d-aspartate receptor antagonist, did not alter ketamine-induced depression of sympathetic activity. These results suggest that ketamine reduces sympathetic activity by mechanisms that are independent of N-methyl-d-aspartate receptor activity.
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Anesthesia and analgesia · Mar 2006
Comparative StudyResidents' and program directors' attitudes toward research during anesthesiology training: a Canadian perspective.
We assessed the attitudes of residents and program directors (PD) toward research training in Canadian anesthesiology residency programs. Questionnaires were sent to all 476 anesthesiology residents in Canada and a modified questionnaire was sent to the PD of each of the 16 anesthesiology programs between November 2003 and April 2004. There was a 60% response rate to the resident questionnaire and 95% from the PDs. ⋯ Residents regard the time needed to learn clinical anesthesia, schedule conflicts, inadequate faculty support, and a lack of protected research time as the top barriers to undertaking a research project. PDs do not consider schedule conflicts or a lack of time as important barriers for resident research. Seventy-five percent of residents would prefer to do another academic activity, such as learning transesophageal echocardiography or taking postgraduate programs in education, rather than completing a research project during their residency.
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Anesthesia and analgesia · Mar 2006
Case ReportsUnanticipated difficult endotracheal intubations in patients with cervical spine instrumentation.
We present two cases of unanticipated difficult airway in patients requiring reoperation after cervical spine instrumentation. In both cases, the upper airway examination was normal, and fiberoptic-guided intubation proceeded with the patient sedated and breathing spontaneously. ⋯ Later review of radiographs showed the previously unrecognized protrusion of cervical hardware into the meso- and hypopharynx. We recommend that anesthesiologists review recent radiographic studies for potential airway compromise before approaching the airway of patients presenting for revision of cervical instrumentation.
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Anesthesia and analgesia · Mar 2006
Anesthetic, patient, and surgical risk factors for neurologic complications after prolonged total tourniquet time during total knee arthroplasty.
Nerve injury after prolonged tourniquet inflation results from the combined effects of ischemia and mechanical trauma. Tourniquet release, allowing a reperfusion interval of 10-30 min followed by re-inflation, has been recommended to extend the duration of total tourniquet time. However, this practice has not been confirmed clinically. ⋯ Postoperative neurologic dysfunction was associated with younger age (P < 0.001; odds ratio = 0.7 per 10-yr increase), longer tourniquet time (P < 0.001; odds ratio = 2.8 per 30-min increase), and preoperative flexion contracture >20 degrees (P = 0.002; odds ratio = 3.9). In a subset of 116 patients with tourniquet times > or =180 min, longer duration of deflation was associated with a decreased frequency of neurologic complications (P = 0.048). We conclude that the likelihood of neurologic dysfunction increases with total tourniquet time and that a reperfusion interval only modestly decreases the risk of nerve injury.