Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2017
ReviewAortocaval Compression Syndrome: Time to Revisit Certain Dogmas.
More than 70 years ago, the phenomenon of "postural shock" in the supine position was described in healthy women in late pregnancy. Since then, avoidance of the supine position has become a key component of clinical practice. Indeed, performing pelvic tilt in mothers at term to avoid aortocaval compression is a universally adopted measure, particularly during cesarean delivery. ⋯ For example, magnetic resonance imaging of women at term in the supine and tilted positions has challenged the dogma that 15° of left tilt is sufficient to relieve inferior vena cava compression. A clinical investigation of healthy term women undergoing elective cesarean delivery with spinal anesthesia found no difference in neonatal acid-base status between women randomized to be either tilted to the left by 15° or to be in the supine position, if maternal systolic blood pressure is maintained at baseline with a crystalloid coload and prophylactic phenylephrine infusion. This review presents a fresh look at the decades of evidence surrounding this topic and proposes a reevaluation and appraisal of current guidelines regarding entrenched practices.
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Anesthesia and analgesia · Dec 2017
Comparative StudyMonte Carlo Simulations Comparing Fisher Exact Test and Unequal Variances t Test for Analysis of Differences Between Groups in Brief Hospital Lengths of Stay.
We examined type I and II error rates for analysis of (1) mean hospital length of stay (LOS) versus (2) percentage of hospital LOS that are overnight. These 2 end points are suitable for when LOS is treated as a secondary economic end point. ⋯ For studies with LOS to be used as a secondary end point of economic interest, there is currently considerable interest in the planned analysis being for the percentage of patients suitable for ambulatory surgery (ie, hospital LOS equals 0 or 1 midnight). Our results show that there need not be a loss of statistical power when groups are compared using this binary end point, as compared with either Welch method or Wilcoxon rank sum test.
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Anesthesia and analgesia · Dec 2017
Esmolol Administration to Control Tachycardia in an Ovine Model of Peritonitis.
Excessive adrenergic signaling may be harmful in sepsis. Using β-blockers to reduce sympathetic overactivity may modulate sepsis-induced cardiovascular, metabolic, immunologic, and coagulation alterations. Using a randomized ovine fecal peritonitis model, we investigated whether administration of a short-acting β-blocker, esmolol, could control tachycardia without deleterious effects on hemodynamics, renal perfusion, cerebral perfusion, cerebral metabolism, or outcome. ⋯ In this ovine model of abdominal sepsis, early control of tachycardia by esmolol was associated with a transient increase in stroke volume, followed by earlier hypotension. There were no significant effects of esmolol on cerebral perfusion, metabolism, urine output, or survival.
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Anesthesia and analgesia · Dec 2017
General Anesthesia Imposes Negative Effects on Heart Rate and Blood Pressure Regulation in Patients With a History of Head and Neck Radiation Therapy.
Head and neck radiation therapy (HNRT) impairs baroreflex sensitivity, and it may potentiate the effects of anesthetics on heart rate (HR) and blood pressure (BP) regulation. Currently, the impacts of HNRT on HR and BP under anesthesia remain unclear. ⋯ The significant finding in the study was that general anesthesia imposed a negative chronotropic effect on HR in the group given HNRT. Therefore, one should be watchful for bradycardia in these patients; particularly those with low BPs. Their hemodynamics may rapidly progress into an unstable status when bradycardia and hypotension develop altogether.
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Anesthesia and analgesia · Dec 2017
The Assignment of American Society of Anesthesiologists Physical Status Classification for Adult Polytrauma Patients: Results From a Survey and Future Considerations.
The American Society of Anesthesiologists (ASA) physical status (PS) classification system assesses the preoperative health of patients. Previous studies demonstrated poor interrater reliability and variable ASA PS scores, especially in trauma scenarios. There are few studies that evaluated the assignment of ASA PS scores in trauma patients and no studies that evaluated ASA PS assignment in severely injured adult polytrauma patients. Our objective was to assess interrater reliability and identify sources of discrepancy among anesthesiologists and trauma surgeons in designating ASA PS scores to adult polytrauma patients. ⋯ This study demonstrates fair interrater reliability beyond that expected by chance of the ASA PS scores among anesthesiologists and trauma surgeons when assessing adult polytrauma patients. Although the ASA PS is used in some trauma risk stratification models, discrepancies of ASA PS scores assigned to trauma cases exist. Future modifications of the ASA PS guidelines should aim to improve the interrater reliability of ASA PS scores in trauma patients. Further studies are warranted to determine the value of the ASA PS score as a trauma prognostic metric.