Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2002
Comparative StudyThe relationship between movement-evoked versus spontaneous pain and peak expiratory flow after abdominal hysterectomy.
The pathogenesis of postoperative lung dysfunction implies a role for movement-evoked pain (e.g., splinting/hypoventilation because of pain avoidance). However, interactions between evoked pain and respiratory physiology are poorly understood. Thus, we examined the relationship between evoked versus spontaneous pain and one index of pulmonary function. In 25 patients having undergone a hysterectomy, visual analog scale ratings (100 mm) for spontaneous pain (REST) and pain during sitting (SIT), forced expiration (BLOW), and coughing (COUGH) were measured together with peak expiratory flow (PEF) at eight time points during postoperative Days 1 and 2. Secondary outcome measures included oxygen saturation and oxygen requirements. Pain was significantly correlated with PEF for COUGH, SIT, BLOW, and REST at eight, seven, four, and two of the eight studied time points, respectively. Mean visual analog scale scores [SE] for COUGH (26.1 mm [1.7]) and SIT (21.5 mm [1.5]) were greater (P < 0.05) than REST (10.5 mm [0.8]), and COUGH was greater (P < 0.05) than BLOW (16.8 mm [1.3]). All pain measures diminished (P < 0.05), and PEF reductions improved (P < 0.05) across the study period. We hypothesize that the consistent negative correlation of COUGH-evoked pain with PEF is, in part, caused by avoidance of coughing, which ultimately limits deep inspiration, lung reexpansion, and clearance of secretions. ⋯ Movement-evoked pain may be an important contributor to postoperative complications, but its mechanisms are poorly understood. This study provides the first evidence that postoperative evoked pain correlates with lung function and highlights the need for future research on mechanisms and implications of this phenomenon.
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Anesthesia and analgesia · Dec 2002
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of three antiemetic combinations for the prevention of postoperative nausea and vomiting.
In this study we compared the efficacy and safety of three antiemetic combinations in the prevention of postoperative nausea and vomiting (PONV). Ninety ASA status I-II women, aged 18-65 yr, undergoing general anesthesia for major gynecological surgery, were included in a prospective, randomized, double-blinded study. A standardized anesthetic technique and postoperative analgesia (intrathecal morphine plus IV patient-controlled analgesia (PCA) with morphine) were used in all patients. Patients were randomly assigned to receive ondansetron 4 mg plus droperidol 1.25 mg after the induction of anesthesia and droperidol 1.25 mg 12 h later (Group 1, n = 30), dexamethasone 8 mg plus droperidol 1.25 mg after the induction of anesthesia and droperidol 1.25 mg 12 h later (Group 2, n = 30), or ondansetron 4 mg plus dexamethasone 8 mg after the induction of anesthesia and placebo 12 h later (Group 3, n = 30). A complete response, defined as no PONV in 48 h, occurred in 80% of patients in Group 1, 70% in Group 3, and 40% in Group 2 (P = 0.004 versus Groups 1 and 3). The incidences of side effects and other variables that could modify the incidence of PONV were similar among groups. In conclusion, ondansetron, in combination with droperidol or dexamethasone, is more effective than dexamethasone in combination with droperidol in women undergoing general anesthesia for major gynecological surgery with intrathecal morphine plus IV PCA with morphine for postoperative analgesia. ⋯ The combination of ondansetron plus dexamethasone or droperidol was significantly better than the combination of dexamethasone plus droperidol in the prophylaxis of postoperative nausea and vomiting in women undergoing general anesthesia for major gynecological surgery, with intrathecal and IV morphine (patient-controlled analgesia) for management of postoperative pain.
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Anesthesia and analgesia · Dec 2002
Randomized Controlled Trial Clinical TrialThe effect of increased FIO(2) before tracheal extubation on postoperative atelectasis.
General anesthesia promotes pulmonary atelectasis, which can be eliminated by a vital capacity (VC) maneuver (inflation of the lungs to 40 cm H(2)O for 15 s). High-inspired oxygen concentration favors recurrence of atelectasis. Therefore, 100% oxygen before tracheal extubation may contribute to atelectasis. To evaluate whether the use of 100% oxygen before extubation increases the amount of postoperative atelectasis, we studied 30 adults scheduled for elective surgery of the extremities. Ten minutes before the presumed end of surgery, patients were randomly assigned to (a) a fraction of inspired oxygen (FIO(2)) = 1.0 (n = 10), (b) VC maneuver + FIO(2) = 1.0 (n = 10), or (c) VC maneuver + FIO(2) = 0.4 (n = 10). The amount of atelectasis was measured by computed tomography scan, and oxygenation was studied by arterial blood gas analysis. Data were analyzed by one-way analysis of variance with Bonferroni correction. Results are presented as mean +/- SD; P < 0.05 was considered significant. In the VC maneuver + FIO(2) = 0.4 group, postoperative atelectasis was smaller (2.6% +/- 1.1% of total lung surface, P < 0.05) than in the FIO(2) = 1.0 group (8.3% +/- 6.2%) and in the VC maneuver + FIO(2) = 1.0 group (6.8% +/- 3.4%). Oxygen 100% at the end of general anesthesia promotes postoperative atelectasis. A safety margin in terms of oxygenation during tracheal extubation is essential, and further studies should therefore evaluate whether atelectasis formation could be prevented despite the use of 100% oxygen. ⋯ For safety reasons, it is common to ventilate patients with 100% oxygen before tracheal extubation. This study demonstrates that this practice favors postoperative atelectasis.