Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2001
Randomized Controlled Trial Comparative Study Clinical TrialNormal saline versus lactated Ringer's solution for intraoperative fluid management in patients undergoing abdominal aortic aneurysm repair: an outcome study.
Metabolic acidosis and changes in serum osmolarity are consequences of 0.9% normal saline (NS) solution administration. We sought to determine if these physiologic changes influence patient outcome. Patients undergoing aortic reconstructive surgery were enrolled and were randomly assigned to receive lactated Ringer's (LR) solution (n = 33) or NS (n = 33) in a double-blinded fashion. Anesthetic and fluid management were standardized. Multiple measures of outcome were monitored. The NS patients developed a hyperchloremic acidosis and received more bicarbonate therapy (30 +/- 62 mL in the NS group versus 4 +/- 16 mL in the LR group; mean +/- SD), which was given if the base deficit was greater than -5 mEq/L. The NS patients also received a larger volume of platelet transfusion (478 +/- 302 mL in the NS group versus 223 +/- 24 mL in the LR group; mean +/- SD). When all blood products were summed, the NS group received significantly more blood products (P = 0.02). There were no differences in duration of mechanical ventilation, intensive care unit stay, hospital stay, and incidence of complications. When NS was used as the primary intraoperative solution, significantly more acidosis was seen on completion of surgery. This acidosis resulted in no apparent change in outcome but required larger amounts of bicarbonate to achieve predetermined measurements of base deficit and was associated with the use of larger amounts of blood products. These changes should be considered when choosing fluids for surgical procedures involving extensive blood loss and requiring extensive fluid administration. ⋯ Predominant use of 0.9% saline solution in major surgery has little impact on outcome as assessed by duration of mechanical ventilation, intensive care unit stay, hospital stay, and postoperative complications, but it does appear to be associated with increased perioperative blood loss.
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Anesthesia and analgesia · Oct 2001
Randomized Controlled Trial Clinical TrialThe concentration-effect relationship of the respiratory depressant effects of alfentanil and fentanyl.
The relative potencies of fentanyl and alfentanil for respiratory depression were determined in eight healthy male volunteers in a double-blinded, randomized study with a cross-over design. The drugs were delivered by computer-driven infusion with logarithmically ascending plasma concentrations until the respiratory rate reached 2/min and/or oxygen saturation decreased below 85% with subjects breathing room air. Ventilation was measured with respiratory inductive plethysmography, indirect calorimetry, and arterial blood gas analysis, and plasma drug concentrations were determined. Pharmacodynamic modeling was performed using a fractional E(max) model for minute volume and respiratory rate and the concentrations producing 50% depression (i.e., apparent 50% effective concentration [EC(50)] values) were determined. Both drugs decreased ventilation in a similar manner, and drug infusions were terminated at mean +/- SD measured plasma concentrations of 254 +/- 88 ng/mL and 5.1 +/- 1.7 ng/mL for alfentanil and fentanyl, respectively. Alfentanil decreased minute volume from baseline by 54% +/- 19% and respiratory rate by 40% +/- 11% with EC(50) values of 234 +/- 57 ng/mL and 195 +/- 101 ng/mL. The respective decreases for fentanyl were 50% +/- 11%, 41% +/- 15%, and the estimated EC(50) values were 6.1 +/- 1.4 ng/mL and 3.5 +/- 1.4 ng/mL, respectively. Using the apparent EC(50) values, the calculated potency ratio for alfentanil:fentanyl was (mean and 95% confidence interval) 1:39 (1:31-1:46) for minute volume and 1:51 (1:34-1:68) for respiratory rate. This is analogous to the analgesic effect studied earlier. The findings support the notion of parallel analgesic and respiratory depressant effects of alfentanil and fentanyl. Therefore equianalgesic concentrations of both drugs will lead to equally pronounced respiratory depression. ⋯ This double-blinded, randomized study evaluated the potency ratio of alfentanil and fentanyl-induced respiratory depression. The findings support the notion of parallel analgesic and respiratory depressant effects of alfentanil and fentanyl. Therefore equianalgesic concentrations of both drugs will lead to equally pronounced respiratory depression.
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Anesthesia and analgesia · Oct 2001
Randomized Controlled Trial Clinical TrialThe effect of timing of dolasetron administration on its efficacy as a prophylactic antiemetic in the ambulatory setting.
Dolasetron (12.5 mg IV) is effective in both preventing and treating postoperative nausea and vomiting (PONV) after ambulatory surgery. However, the optimal timing of dolasetron administration and its effect on the patient's quality of life after discharge have not been established. One-hundred-five healthy, consenting women undergoing gynecologic laparoscopic procedures with a standardized general anesthetic technique were enrolled in this randomized, double-blinded study. Group 1 received dolasetron 12.5 mg IV 10-15 min before the induction of anesthesia; Group 2 received dolasetron 12.5 mg IV at the end of the laparoscopy (79 +/- 48 min later than Group 1); and Group 3 received dolasetron 12.5 mg IV at the end of anesthesia (93 +/- 52 min later than Group 1). The incidence of PONV, complete responses (defined as no emetic episodes and no rescue medication within the 24-h period after anesthesia), recovery profiles, and patient satisfaction were recorded. In the postanesthesia care unit and during the 24-h follow-up period, the incidence of nausea and vomiting, as well as the need for rescue antiemetics, did not differ significantly among the three groups. The percentages of patients with complete responses to the study drug within the first postoperative 24 h were also similar in all three groups (55%, 59%, and 52% for Groups 1, 2, and 3, respectively). The early and intermediate recovery profiles, including resumption of a normal diet and patient satisfaction with the control of PONV, were not different among the three study groups. Dolasetron 12.5 mg IV administered before the induction of anesthesia is as effective as dolasetron given at the end of laparoscopy or at the end of anesthesia in preventing PONV after outpatient laparoscopy. ⋯ The timing of dolasetron administration appears to have little effect on its efficacy when administered as a prophylactic antiemetic in the ambulatory setting.
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Anesthesia and analgesia · Oct 2001
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of fentanyl, sufentanil, and remifentanil for fast-track cardiac anesthesia.
Cardiac surgery is estimated to cost $27 billion annually in the United States. In an attempt to decrease the costs of cardiac surgery, fast-track programs have become popular. The purpose of this study was to compare the effects of three different opioid techniques for cardiac surgery on postoperative pain, time to extubation, time to intensive care unit discharge, time to hospital discharge, and cost. Ninety adult patients undergoing cardiac surgery were randomized to a fentanyl-based, sufentanil-based, or remifentanil-based anesthetic. Postoperative pain was measured at 30 min after extubation and at 6:30 AM on the first postoperative day. Pain scores at both times were similar in all three groups (P > 0.05). Median ventilator times of 167, 285, and 234 min (P > 0.05), intensive care unit stays of 18.8, 19.8, and 21.5 h (P > 0.05), and hospital stays of 5, 5, and 5 days (P > 0.05) for the Fentanyl, Sufentanil, and Remifentanil groups did not differ. Three patients needed to be tracheally reintubated: two in the Sufentanil group and one in the Fentanyl group. Median anesthetic costs were largest in the Remifentanil group ($140.54 [$113.54-$179.29]) and smallest in the Fentanyl group ($43.33 [$39.36-$56.48]) (P < or = 0.01), but hospital costs were similar in the three groups: $7841 (Fentanyl), $5943 (Sufentanil), and $6286 (Remifentanil) (P > 0.05). We conclude that the more expensive but shorter-acting opioids, sufentanil and remifentanil, produced equally rapid extubation, similar stays, and similar costs to fentanyl, indicating that any of these opioids can be recommended for fast-track cardiac surgery. ⋯ To conserve resources for cardiac surgery, fentanyl-, sufentanil-, and remifentanil-based anesthetics were compared for duration of mechanical ventilation, intensive care unit length of stay, hospital length of stay, and cost. The shorter-acting anesthetics, sufentanil and remifentanil, produced equally rapid extubation, similar stays, and similar costs to fentanyl; thus, any of these opioids can be recommended for fast-track cardiac surgery.
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Anesthesia and analgesia · Oct 2001
Randomized Controlled Trial Comparative Study Clinical TrialAmbulatory surgery: room air versus nasal cannula oxygen during transport after general anesthesia.
We compared outpatients transported to the postanesthesia care unit (PACU) while breathing room air to 2-4 L/min nasal cannula oxygen (O2) to test the hypothesis that routine supplemental O2 during transport is not required after general anesthesia in an ambulatory surgery center. We also examined whether the arbitrary arrival PACU O2 saturations of > 92% may be used to predict an infrequent incidence of subsequent significant desaturations (< 90%) in the PACU. One-hundred-ninety patients were randomized to receive either room air or 2-4 L/min nasal cannula for transport to PACU after receiving general anesthesia. O2 saturations were recorded before surgery, just before leaving the operating room, and upon arrival in the PACU. The lowest O2 saturation occurring in the PACU was also recorded. The mean arrival PACU O2 saturation was 95.0 in the Room Air group, compared with 97.2 for the Nasal Cannula (NC) group, a statistically significant difference (P < 0.001). In the Room Air group, 20% had arrival O2 saturations < or = 92%, and half of these (10%) had O2 saturations < 90%. In the NC group, 6% had O2 saturations < or = 92%, of which one third (2%) were < 90% on arrival in the PACU. All of these initial desaturations were easily corrected with face-tent O2 administration, deep breathing, or both. Subgroup analysis revealed that patients whose ages were 60 yr or older or those weighing 100 kg or more had lower arrival room air saturations than their younger or slimmer counterparts. In the Room Air group, only three (3.9%) of the patients that arrived in PACU with O2 saturations > 92% had subsequent desaturations < 90%, compared with seven (7.9%) in the NC group. We conclude that most adult patients undergoing ambulatory surgery can be transported safely to the PACU breathing room air after general anesthesia. However, patients whose age was > or = 60 yr or weight was > or = 100 kg, or for whom transient O2 desaturation on transport may be harmful, should be transported while breathing nasal O2 via nasal cannula. ⋯ Most adult patients undergoing ambulatory surgery can be transported safely to the PACU breathing room air after general anesthesia. However, patients whose age was > or = 60 yr or weight > or = 100 kg, or for whom transient O2 desaturation on transport may be harmful, should be transported while breathing oxygen via nasal cannula.