Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialThe sunburn pain model: the stability of primary and secondary hyperalgesia over 10 hours in a crossover setting.
It was our aim to study the within-day stability and between-day repeatability of ultraviolet B (UVB) light-induced primary and secondary hyperalgesia over 10 h. Twenty hours after UVB irradiation of a skin spot (r = 2.5 cm) on the upper leg of 8 healthy volunteers the areas of secondary hyperalgesia to pinprick and pain tolerance thresholds to heat (HPTT) and electrical stimuli (5 and 250 Hz, electrical pain tolerance thresholds [EPTT]) were assessed. Measurements were repeated for 10 h at 2-h intervals and in 2 different sessions. Large areas of secondary hyperalgesia to pin prick were observed (5995 mm(2); SD, 1645). Primary hyperalgesia was evidenced by significant decreases of HPTT (mean difference, 6.5 degrees C; 95% confidence interval, 6.1-6.8; P < 0.001) and EPTT at 250 Hz (mean difference, 0.45 mA; 95% confidence interval, 0.13-0.78; P < 0.05) compared to normal skin. There was no trend within one session of either primary (P = 0.14 for HPTT) or secondary hyperalgesia (P = 0.95) and no difference between the two sessions (primary hyperalgesia, P = 0.28; secondary hyperalgesia, P = 0.07). The sunburn pain model provides a long time course of stable hyperalgesia with a high within-day stability and between-day repeatability for primary and secondary hyperalgesia. ⋯ The sunburn pain model provides a long time course of stable hyperalgesia with a high within-day stability and between-day repeatability for primary and secondary hyperalgesia.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialThe effect of preoperative antiplatelet/anticoagulant prophylaxis on postoperative blood loss in cardiac surgery.
In this study we sought to determine whether preoperative treatment with antiplatelet and/or anticoagulant drugs influences postoperative blood loss after coronary artery bypass graft surgery. Although prophylactic treatment to prevent ischemic events preoperatively is often necessary, the treatment frequently continues until there may be a risk of increased bleeding (i.e., within 5-7 days before surgery). With patient consent, a preincision blood sample was collected prospectively from 93 adult subjects who presented randomly. They consisted of 3 groups regarding their primary preoperative regimen: 1) no preoperative treatment within the week before surgery; 2) platelet adenosine diphosphate (ADP) receptor antagonist; 3) ADP receptor antagonist plus IV heparin. Postoperative chest tube drainage (24 h) in the group that received ADP antagonist alone was more (P < 0.05) than either of the other groups: 503 +/- 56; 633 +/- 55; 439 +/- 29 mL (mean +/- SEM) for Groups 1, 2, and 3, respectively. Combined treatment with ADP antagonist plus heparin infusion appeared to prevent the increased blood loss with the ADP antagonist alone. Preincision and postoperative plasma fibrinogen concentrations were largest (P < 0.05) in the group that received the combination treatment; mean +/- SEM for groups 1, 2, and 3 preincision, 311 +/- 17, 366 +/- 16, and 423 +/- 18 mg/dL, and postoperatively, 229 +/- 16, 267 +/- 13, and 312 +/- 16 mg/dL. Postoperative fibrinogen showed strong dependence on preoperative fibrinogen in all groups (r = 0.576 to 0.825; P = 0.01 to 10(-6)). Prevention of the increased blood loss in the ADP receptor antagonist group by the addition of a heparin infusion may have been attributable to a conservation of coagulation factors, as evidenced by the increased plasma fibrinogen concentrations with combined prophylactic treatment. ⋯ The objective of this study was to determine whether preoperative treatment with antiplatelet and/or anticoagulant drugs influences the extent of blood loss in the 24-h period after cardiac surgery.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialPreoperative rofecoxib oral suspension as an analgesic adjunct after lower abdominal surgery: the effects on effort-dependent pain and pulmonary function.
Rofecoxib is a selective cyclooxygenase-2 inhibitor that reduces pain and inflammation without inhibiting platelet function. We examined its effects on effort-dependent pain, postoperative morphine requirements, and pulmonary function in 48 patients recovering from open abdominal surgery. Spirometric measurement of forced expiratory volume(1) and vital capacity (FVC) were assessed preoperatively. One hour before the induction of a standardized general anesthetic, patients were given either placebo oral suspension (Group A), or rofecoxib oral suspension (25 mg [Group B] or 50 mg [Group C]) in a double-blinded manner. Postoperative pain control was provided with IV morphine in the postanesthesia care unit and IV-patient-controlled analgesia morphine on the patient care unit. Morphine dose, pain intensity at rest, and pain after respiratory effort (postoperative spirometry) were assessed at 12 and 24 h after study drug administration. The patient-controlled analgesia morphine dose at 24 h was reduced 44% in Group B (30.3 +/- 17.5 mg) and 59% in Group C (22.1 +/- 16.5 mg) versus Group A (53.7 +/- 31.1 mg); P < 0.01 (A versus B). At 12 h, pain scores at rest and after spirometry were lower in Groups B and C than in A (P < 0.05). At 24 h, resting pain scores were lowest in Group C (P < 0.05). Twelve-hour FVC was best preserved in Group C (P < 0.03). There were no inter-group differences in adverse effects or perioperative blood loss. Rofecoxib oral suspension provided a morphine-sparing effect, as well as improvements in pain control and 12-h FVC in patients recovering from open abdominal surgery. ⋯ Rofecoxib belongs to class of analgesics known as cyclooxygenase-2 inhibitors that reduce pain and inflammation with less risk of bleeding than standard nonsteroidal antiinflammatory drugs. We found that patients treated with rofecoxib 25 or 50 mg before open abdominal surgery required less IV morphine during the first day of recovery. Despite reductions in morphine requirements, rofecoxib-treated patients reported lower pain intensity scores at rest and after a vigorous cough. In the 50-mg group, improvements in pain control correlated with greater preservation of baseline cough effectiveness (vital capacity) at 12 h. These findings may offer clinical advantages in patients with preexisting pulmonary disease.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialAdministration of 100% oxygen before removal of the laryngeal mask airway does not affect postanesthetic arterial partial pressure of oxygen.
Breathing 100% oxygen at the end of general anesthesia has been shown to worsen postoperative pulmonary gas exchange when an endotracheal tube is used. Counter measures, such as high positive end-expiratory pressure or the vital-capacity maneuver, may limit this effect. Such strategies, however, may be impracticable, or even contraindicated, when the laryngeal mask airway (LMA) is used. Because of the vast differences in design between the LMA and endotracheal tube, we examined postanesthetic blood gas tensions in patients after emergence from anesthesia breathing oxygen via LMA. Sixty-four ASA physical status I-II patients undergoing general anesthesia for 60 min with LMA were randomly assigned to receive either 100% or 30% oxygen during emergence from anesthesia and removal of LMA. Postoperative blood gas measurements were taken at 30 and 60 min after removal of the LMA. At either measurement, patients treated with 100% oxygen essentially had the same arterial partial pressure of oxygen (60-min measurement: 83 +/- 8 versus 85 +/- 7 mm Hg [mean +/- SD], P = 0.14) as those treated with 30% oxygen. We conclude that breathing 100% oxygen at the end of general anesthesia does not worsen postoperative pulmonary gas exchange when an LMA is used. ⋯ The endotracheal tube and laryngeal mask airway are substantially different artificial airways used to ventilate the lungs of anesthetized patients. Breathing 100% oxygen before removing the endotracheal tube results in lung function defects. This study shows that oxygen breathing before removing the laryngeal mask airway has no effect on pulmonary function.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Comparative Study Clinical TrialPostanesthesia care unit recovery times and neuromuscular blocking drugs: a prospective study of orthopedic surgical patients randomized to receive pancuronium or rocuronium.
In this study, we examined the effect of choice of neuromuscular blocking drug (NMBD) (pancuronium versus rocuronium) on postoperative recovery times and associated adverse outcomes in patients undergoing orthopedic surgical procedures. Seventy patients were randomly allocated to a pancuronium or rocuronium group. On arrival to the postanesthesia care unit (PACU) and again 30 min later, train-of-four ratios were quantified by using acceleromyography. Immediately after acceleromyographic measurements, patients were assessed for signs and symptoms of residual paresis. During the PACU admission, episodes of hypoxemia, nausea, and vomiting were recorded. The time required for patients to meet discharge criteria and the time of actual PACU discharge were noted. Forty percent of patients in the pancuronium group had train-of-four ratios <0.7 on arrival to the PACU, compared with only 5.9% of subjects in the rocuronium group (P < 0.001). Patients in the pancuronium group were more likely to experience symptoms of muscle weakness (blurry vision and generalized weakness; P < 0.001) and hypoxemia (10 patients in the rocuronium group versus 21 patients in the pancuronium group; P = 0.015) during the PACU admission. Significant delays in meeting PACU discharge criteria (50 min [45-60 min] versus 30 min [25-40 min]) and achieving actual discharge (70 min [60-90 min] versus 57.5 min [45-61 min]) were observed when the pancuronium group was compared with the rocuronium group (P < 0.001). In conclusion, our study indicates that PACU recovery times may be prolonged when long-acting NMBDs are used in surgical patients. ⋯ Clinical recovery may be delayed in surgical patients administered long-acting neuromuscular blocking drugs. During the postanesthesia care unit admission, patients randomized to receive pancuronium (versus rocuronium) were more likely to exhibit symptoms of muscle weakness, develop hypoxemia, and require more time to meet discharge criteria.