Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2003
Comparative StudyA comparison of lactated ringer's solution to hydroxyethyl starch 6% in a model of severe hemorrhagic shock and continuous bleeding in dogs.
In this randomized, controlled study in dogs, we examined the short-term effects of blood pressure targeted fluid resuscitation with colloids or crystalloids solutions on systemic oxygen delivery, and lactate blood concentration. Fluid resuscitation using hydroxyethyl starch (HES) 6% to a mean arterial blood pressure (MAP) of 60 mm Hg was compared with lactated Ringer's solution (LR) to a MAP of 60 or 80 mm Hg (LR60 and LR80, respectively). The model was one of withdrawal of blood to a MAP of 40 mm Hg through an arterial catheter that was then connected to a system allowing bleeding to occur throughout the study whenever MAP exceeded 40 mm Hg. Target MAP was maintained for 60 min with a continuous infusion of the designated fluid replacement. All 15 dogs (5 in each group) survived until the last measurement. Blood loss in the LR80 group (2980 +/- 503 mL) (all values mean +/- SD) was larger than in the LR60 and HES60 groups (1800 +/- 389 mL, and 1820 +/- 219 mL, respectively) (P < 0.001). Whereas 840 +/- 219 mL of HES60 was needed to maintain target MAP, 1880 +/- 425 mL of LR was needed in the LR60 group, and 4590 +/- 930 mL in the LR80 group (P < 0.001). Lactate blood concentrations were smaller and delivered O(2) higher in the HES60 group (35 +/- 17 mg/dL and 239 +/- 61 mL/min, respectively) in comparison to the LR60 group (89 +/- 18 mg/dL and 140 +/- 48 mL/min, respectively) and the LR80 group (75 +/- 23 mg/dL and 153 +/- 17 mL/min, respectively) (P = 0.02 and P = 0.026). In conclusion, fluid resuscitation during uncontrolled bleeding, to a target MAP of 60 mm Hg, using HES60 resulted in larger oxygen delivery and smaller systemic lactate A resuscitation to a target MAP of 60 or 80 mm Hg using LR. ⋯ Fluid resuscitation to a target mean arterial blood pressure of 60 mm Hg during uncontrolled bleeding resulted in larger oxygen delivery and smaller systemic lactate concentrations when hydroxyethyl starch 6% was used, in comparison to lactated Ringer's solution resuscitation to a target mean arterial blood pressure of 60 or 80 mm Hg.
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Anesthesia and analgesia · Jan 2003
Review Meta AnalysisNonsteroidal antiinflammatory drugs and the risk of operative site bleeding after tonsillectomy: a quantitative systematic review.
The use of nonsteroidal antiinflammatory drugs (NSAIDs) for analgesia after tonsillectomy is controversial because NSAIDS, through platelet inhibition, may increase the risk of perioperative bleeding. We systematically searched for randomized, controlled trials that reported on the incidence of perioperative bleeding attributable to the use of NSAIDs in patients undergoing tonsillectomy. As secondary outcome measures, we analyzed the quality of pain relief and the incidence of postoperative nausea and vomiting. Twenty-five studies with data from 970 patients receiving a NSAID and 883 receiving a non-NSAID treatment or a placebo were analyzed. Data were combined using a fixed-effect model. Of four bleeding end points (intraoperative blood loss, postoperative bleeding, hospital admission, and reoperation because of bleeding), only reoperation happened significantly more often with NSAIDs: Peto-odds ratio, 2.33 (95% confidence interval [CI], 1.12-4.83) and number-needed-to-treat, 60 (95% CI, 34-277). Compared with opioids, NSAIDs were equianalgesic, and the risk of emesis was significantly decreased (relative risk, 0.73; 95% CI, 0.63-0.85; numbers-needed-to-treat, 9; 95% CI, 5-19). ⋯ The evidence for nonsteroidal antiinflammatory drugs to increase the risk of bleeding after tonsillectomy is equivocal, and the risk-benefit ratio is not straightforward. There is some evidence for an increased likelihood of reoperation because of bleeding. The agenda must be one of further research rather than of clinical recommendations.
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Anesthesia and analgesia · Jan 2003
Randomized Controlled Trial Comparative Study Clinical TrialThe endotracheal tube moves more often in obese patients undergoing laparoscopy compared with open abdominal surgery.
We compared the incidence of movements of the endotracheal tube (ETT) within the trachea in morbidly obese patients undergoing either laparoscopic or open gastroplasty. In a double-blinded, prospective, controlled study, 60 patients (body mass index, 35-60 kg/m(2)) were equally allocated to either laparoscopic LapBand gastroplasty (study group; Group 1) or open laparotomy gastroplasty (control; Group 2), both under standardized general anesthesia. Movements of the ETT were assessed with chest auscultation, peak inspiratory pressure, ETCO(2), SpO(2), and the Rapiscope at predetermined time points: after intubation (baseline values), 5 min before peritoneal inflation in Group 1 and 10 min postintubation in Group 2, at maximal abdominal inflation in Group 1 and 20 min into the procedure in Group 2, 5 min before and 5 min after changing the patient's position from neutral to 10 degrees head up and 10 degrees head down in Group 1 and 30 and 40 min into the procedure in Group 2, 2 min after abdominal deflation and table repositioning in Group 1 and at 50 min in Group 2, and just before extubation in both groups. Twenty-one events of ETT tip movement occurred in both groups. The tube moved in 15 (50%) study (laparoscopy) group patients compared with 6 (20%) controls (laparotomy; P < 0.05), 12 of the former having moved downward either after maximal abdominal insufflation or in association with head-down positioning. The tubes of five study group patients (17%) advanced into the right bronchus, compared with none in the controls (P < 0.05). All changes in position were rectified only by the Rapiscope. ⋯ Abdominal insufflation and changes in table position lead to more frequent movements of the endotracheal tube in obese patients undergoing laparoscopic versus open gastroplasty. The Rapiscope identifies all these changes, but not the clinically available variables.
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Anesthesia and analgesia · Jan 2003
Randomized Controlled Trial Comparative Study Clinical TrialThe effects of clonidine premedication on the blood pressure and tachycardiac responses to ephedrine in elderly and young patients during propofol anesthesia.
We studied the pressor and tachycardiac responses to ephedrine in elderly and young patients given either clonidine or midazolam during propofol anesthesia. In the first experiment, elderly (>60 yr) and young (20-45 yr) patients were randomly allocated to one of four groups according to age and premedicated regimens (n = 16 each; elderly-clonidine [EC], elderly-midazolam [EM], young-clonidine [YC], and young-midazolam [YM]). Under propofol anesthesia, ephedrine was injected, and hemodynamic measurements were made. In the second experiment, with clonidine premedication, elderly patients (n = 16) were given a reduced dose of propofol (EC-LP) and young patients (n = 16) were given an increased dose of propofol (YC-HP). Ephedrine was injected, and he- modynamic measurements were performed. The in-creases in mean blood pressure and heart rate were larger in the EC group than in the EM, YM, and EC-LP groups (P < 0.05). In the YC-HP group, the pressor response to ephedrine tended to be augmented as compared with the YC group but was not statistically significant. These results suggest that clonidine premedication augmented the pressor and tachycardiac responses to ephedrine, especially in elderly patients during a standard dose of propofol anesthesia, and that clonidine, age, and propofol could be involved in the augmentation of the blood pressure and tachycardiac responses to ephedrine. ⋯ Clonidine premedication augments the pressor and tachycardiac responses to ephedrine in elderly patients during standard or large doses of propofol anesthesia but does not augment during small doses of propofol anesthesia. Clonidine, age, and propofol could be involved in the augmentation of the pressor and tachycardiac responses to ephedrine.