Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2002
Randomized Controlled Trial Clinical TrialThe influence of nicardipine-, nitroglycerin-, and prostaglandin E(1)-induced hypotension on cerebral pressure autoregulation in adult patients during propofol-fentanyl anesthesia.
We investigated the influence of drug-induced hypotension at a mean arterial pressure (MAP) of 60-70 mm Hg on cerebral pressure autoregulation in 45 adult patients during propofol-fentanyl anesthesia. Time-averaged mean blood flow velocity in the right middle cerebral artery (Vmca) was continuously measured at a PaCO(2) of 39-40 mm Hg by using transcranial Doppler ultrasonography. Hypotension was induced and maintained with a continuous infusion of nicardipine, nitroglycerin, or prostaglandin E(1). Cerebral autoregulation was tested by a slow continuous infusion of phenylephrine to induce an increase in MAP of 20-30 mm Hg. From the simultaneously recorded data of Vmca and MAP, cerebral vascular resistance (CVR) was calculated as MAP/Vmca. Furthermore, the index of autoregulation (IOR) was calculated as DeltaCVR/DeltaMAP, where DeltaCVR = change in CVR and DeltaMAP = change in MAP. The test was performed twice for each condition on each patient: baseline and hypotension. The IOR during baseline was similar among the groups. During nitroglycerin- and prostaglandin E(1)-induced hypotension, IOR was not different from baseline. In contrast, during nicardipine-induced hypotension, IOR significantly decreased compared with baseline (0.37 +/- 0.08 versus 0.83 +/- 0.07, P < 0.01). In conclusion, nicardipine, but not nitroglycerin or prostaglandin E(1), significantly attenuates cerebral pressure autoregulation during propofol-fentanyl anesthesia. ⋯ Vasodilators may influence cerebral autoregulation by changing cerebral vascular tone. Nicardipine, but not nitroglycerin or prostaglandin E(1), attenuated cerebral pressure autoregulation in normal adult patients during propofol-fentanyl anesthesia.
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Anesthesia and analgesia · Jan 2002
Case ReportsHuman error: the persisting risk of blood transfusion: a report of five cases.
It is common experience that virus transmission, particularly transmission of the human immunodeficiency virus (HIV), is a principal concern of patients and physicians regarding blood transfusion (1). Many physicians are probably unaware that transfusion-transmitted HIV infection is approximately 50 to 100 times less likely to occur than transfusion error (2-4). This misconception may have been encouraged by the scarcity of reports on transfusion error relative to the tremendous public attention focused on HIV infection. We present five cases illustrating how anesthesiologists, intensivists, and emergency physicians are particularly vulnerable to the risk of administering blood to the wrong recipient. All five cases were collected during a 4-yr period. Transfused units of packed red cells totaled approximately 50,000 U during this period in our department. ⋯ Human error leading to the transfusion of blood to an unintended recipient is a major source of transfusion-related fatalities. We report five cases that highlight some specific areas in which transfusion error is likely to occur.
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Anesthesia and analgesia · Jan 2002
Calculating a potential increase in hospital margin for elective surgery by changing operating room time allocations or increasing nursing staffing to permit completion of more cases: a case study.
Administrators routinely seek to increase contribution margin (revenue minus variable costs) to better cover fixed costs, provide indigent care, and meet other community service responsibilities. Hospitals with high operating room (OR) utilizations can allocate OR time for elective surgery to surgeons based partly on their contribution margins per hour of OR time. This applies particularly when OR caseload is limited by nursing recruitment. From a hospital's annual accounting data for elective cases, we calculated the following for each surgeon's patients: variable costs for the entire hospitalization or outpatient visit, revenues, hours of OR time, hours of regular ward time, and hours of intensive care unit (ICU) time. The contribution margin per hour of OR time varied more than 1000% among surgeons. Linear programming showed that reallocating OR time among surgeons could increase the overall hospital contribution margin for elective surgery by 7.1%. This was not achieved simply by taking OR time from surgeons with the smallest contribution margins per OR hour and giving it to the surgeons with the largest contribution margins per OR hour because different surgeons used differing amounts of hospital ward and ICU time. We conclude that to achieve substantive improvement in a hospital's perioperative financial performance despite restrictions on available OR, hospital ward, or ICU time, contribution margin per OR hour should be considered (perhaps along with OR utilization) when OR time is allocated. ⋯ For hospitals where elective surgery caseload is limited by nursing recruitment, to increase one surgeon's operating room time either another surgeon's time must be decreased, nurses need to be paid a premium for working longer hours, or higher-priced "traveling" nurses can be contracted. Linear programming was performed using Microsoft Excel to estimate the effect of each of these interventions on hospital contribution margin.
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Anesthesia and analgesia · Jan 2002
Randomized Controlled Trial Clinical TrialAlkalinization of intracuff lidocaine improves endotracheal tube-induced emergence phenomena.
We sought to evaluate the effect of filling an endotracheal tube cuff with 40 mg lidocaine alone (Group L) or alkalinized lidocaine (Group LB) in comparison to an Air Control group (Group C) on adverse emergence phenomena in a randomized controlled study (n = 25 in each group). The incidence of sore throat was decreased for Group LB in comparison to Group L during the 24 postextubation hours. The difference between Group L and Group C remained significant in the two postextubation hours only. Plasma lidocaine levels increased when lidocaine was alkalinized (C(max) were 62.5 +/- 34.0 ng/mL and 3.2 +/- 1.0 ng/mL for Groups LB and L, respectively). Cough and restlessness before tracheal extubation were decreased in Group LB compared with Group L and in Group L compared with Group C. Nausea, postoperative vomiting, dysphonia, and hoarseness were increased after extubation in Group C compared with the liquid groups, and a better tolerance was recorded with Group LB compared with Group L. The increase of arterial blood pressure and cardiac frequencies during the extubation period was less in the liquid groups than in the control group and less in Group LB compared with Group L. We concluded that use of intracuff alkalinized lidocaine is an effective adjunct to endotracheal intubation. ⋯ Use of 40 mg of alkalinized lidocaine, rather than lidocaine or air, to fill the endotracheal tube cuff reduces the incidence of sore throat in the postoperative period. This approach also decreases hemodynamic effects, restlessness, dysphonia, and hoarseness.
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Anesthesia and analgesia · Jan 2002
Randomized Controlled Trial Clinical TrialThe clinical efficacy and pharmacokinetics of intraperitoneal ropivacaine for laparoscopic cholecystectomy.
Postoperative pain after laparoscopic surgery is less than after laparotomy, and patients may benefit from an intraperitoneal injection of local anesthetic. Thirty-seven ASA physical status I or II patients received in double-blinded fashion 20 mL of 0.9% saline solution (placebo), ropivacaine 0.25% (Rop 0.25%), or ropivacaine 0.75% (Rop 0.75%) immediately after trocar placement and at the end of surgery. We measured pain and morphine consumption until 20 h after surgery. Plasma ropivacaine concentrations were measured. The three groups were comparable for shoulder pain, parietal pain, and incidence of side effects. Visceral pain at rest, during cough, and on movement and total consumption of morphine were significantly smaller in Groups Rop 0.25% and Rop 0.75% when compared with Placebo. Although no adverse effect occurred in any patient, the largest dose led to large plasma concentrations of ropivacaine (2.93 +/- 2.46 microg/mL and 3.76 +/- 3.01 microg/mL after the first and second injection, respectively). We conclude that intraperitoneal administration of ropivacaine before and after surgery significantly decreases postoperative pain. Because the smaller dosage (2 x 50 mg) provided similar analgesia and was associated with significantly smaller plasma concentrations than the larger dosage (2 x 150 mg), this smaller dosage seems more appropriate. ⋯ Intraperitoneal ropivacaine 100 mg injected during laparoscopic cholecystectomy significantly decreased postoperative pain when compared with injection of intraperitoneal placebo. At this dose, plasma concentrations remained in the nontoxic range,