Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2011
Clinical TrialCardiac index in term pregnant women in the sitting, lateral, and supine positions: an observational, crossover study.
Aortocaval compression may affect maternal hemodynamic indices and fetal well-being in various maternal positions. There has been much debate regarding the optimal position for performing neuraxial blockade for labor analgesia and cesarean delivery. We hypothesized that in pregnant women at term, cardiac index (CI) may be improved in the lateral positions as compared with the flexed sitting position. Our primary outcome was to measure CI as assessed by suprasternal Doppler. ⋯ Positioning for neuraxial anesthesia may influence maternal hemodynamic variables. We found no difference in healthy fetal blood flow indices among positions, suggesting that these changes are not clinically significant. This study provides new physiological information on the changes that occur in a group in whom it has not been practical to study previously. Further study is necessary to determine whether these changes are significant in the presence of neuraxial anesthesia or in the high-risk parturient.
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Anesthesia and analgesia · Aug 2011
ReviewThe physiologic implications of isolated alpha(1) adrenergic stimulation.
Phenylephrine and methoxamine are direct-acting, predominantly α(1) adrenergic receptor (AR) agonists. To better understand their physiologic effects, we screened 463 articles on the basis of PubMed searches of "methoxamine" and "phenylephrine" (limited to human, randomized studies published in English), as well as citations found therein. Relevant articles, as well as those discovered in the peer-review process, were incorporated into this review. ⋯ Furthermore, the cost of increased blood pressure after pure α(1)-agonism is almost invariably decreased cardiac output, likely due to increases in venous resistance. The venous system contains α(1) ARs, and though stimulation of α(1) ARs decreases capacitance and may transiently increase venous return, this gain may be offset by changes in afterload, venous compliance, and venous resistance. Data on the effects of α(1) stimulation in the central nervous system show conflicting changes, while experimental animal data suggest that renal blood flow is reduced by α(1)-agonists, and both animal and human data suggest that gastrointestinal perfusion may be reduced by α(1) tone.
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Anesthesia and analgesia · Aug 2011
Automatic notifications mediated by anesthesia information management systems reduce the frequency of prolonged gaps in blood pressure documentation.
Arterial blood pressure (BP) measurement at least every 5 minutes is part of the American Society of Anesthesiologists' monitoring standard, but prolonged BP gaps in electronic anesthesia records have been noted. We undertook multicenter studies to determine the frequency of cases with at least 1 interval ≥10 minutes between successive BP measurements and then to ascertain whether educational feedback via an electronic, near real-time notification system alerting providers to the presence of such gaps would reduce their incidence. ⋯ BP gaps of ≥10 minutes were common in electronic anesthesia records, and their incidence was reduced but not eliminated by near real-time feedback to providers. The American Society of Anesthesiologists' standard for BP documentation every 5 minutes might not be achievable with current practices and technology. Anesthesia information management systems users need to be cognizant of the potential for gaps in BP measurement, take steps to minimize their occurrence, and document an explanation when such failures occur.
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Anesthesia and analgesia · Aug 2011
Comparative Study Clinical TrialTransient hemodynamic change and accuracy of arterial blood pressure-based cardiac output.
The purpose of this study was to determine the effects of transient arterial blood pressure change on the accuracy of the FloTrac™/Vigileo™ monitor (Edwards Lifesciences, Irvine, CA). ⋯ The FloTrac/Vigileo measured stroke volume with reasonable accuracy during transient hypotension but overestimated stroke volume during transient hypertension.
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Anesthesia and analgesia · Aug 2011
Biography Historical ArticleRoss C. Terrell, PhD, an anesthetic pioneer.
On December 30, 2010, Ross C. Terrell, PhD, died. With his passing at age 85, we lost one of the pioneers of modern anesthesia. Terrell synthesized most of the inhalation anesthetics used today, including desflurane, enflurane, isoflurane, and sevoflurane.