Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2003
Clinical TrialThe effect of right versus left lateral decubitus positions on induction of spinal anesthesia for cesarean delivery.
Induction of spinal anesthesia for cesarean delivery in the left lateral (LL) decubitus position combined with intraoperative left uterine displacement may result in pooling of local anesthetic onto one side of the body. We studied the effect of the right lateral (RL) and LL decubitus positions during placement of spinal anesthesia on the intrathecal spread of 0.5% hyperbaric bupivacaine plus fentanyl in 60 term parturients. Though all parturients acquired a loss of cold sensation at T4 15 min after intrathecal injection, more parturients in the LL group than in the RL group did so at 5 min (P < 0.05). The maximum levels of sensory blockades, amounts of fluid, vasopressor, and supplementary analgesia used, and the incidence of postoperative complications were similar. We conclude that the two positions can be used equally well when hyperbaric bupivacaine and fentanyl are used in cesarean delivery under spinal anesthesia. ⋯ We conducted a double-blinded randomized trial comparing the spread of spinal anesthesia placed with a parturient in either the right or left lateral position. There was a faster onset in the left lateral group; however, the maximum block heights and the time taken to achieve them were similar in both groups.
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Anesthesia and analgesia · Dec 2003
Risk factors for acute lung injury after thoracic surgery for lung cancer.
Acute lung injury (ALI) may complicate thoracic surgery and is a major contributor to postoperative mortality. We analyzed risk factors for ALI in a cohort of 879 consecutive patients who underwent pulmonary resections for non-small cell lung carcinoma. Clinical, anesthetic, surgical, radiological, biochemical, and histopathologic data were prospectively collected. The total incidence of ALI was 4.2% (n = 37). In 10 cases, intercurrent complications (bronchopneumonia, n = 5; bronchopulmonary fistula, n = 2; gastric aspiration, n = 2; thromboembolism, n = 1) triggered the onset of ALI 3 to 12 days after surgery, and this was associated with a 60% mortality rate (secondary ALI). In the remaining 27 patients, no clinical adverse event preceded the development of ALI-0 to 3 days after surgery-that was associated with a 26% mortality rate (primary ALI). Four independent risk factors for primary ALI were identified: high intraoperative ventilatory pressure index (odds ratio, 3.5; 95% confidence interval, 1.7-8.4), excessive fluid infusion (odds ratio, 2.9; 95% confidence interval, 1.9-7.4), pneumonectomy (odds ratio, 2.8; 95% confidence interval, 1.4-6.3), and preoperative alcohol abuse (odds ratio, 1.9; 95% confidence interval, 1.1-4.6). In conclusion, we describe two clinical forms of post-thoracotomy ALI: 1). delayed-onset ALI triggered by intercurrent complications and 2). an early form of ALI amenable to risk-reducing strategies, including preoperative alcohol abstinence, lung-protective ventilatory modes, and limited fluid intake. ⋯ In an observational study including all patients undergoing lung surgery, we describe two clinical forms of acute lung injury (ALI): a delayed-onset form triggered by intercurrent complications and an early form associated with preoperative alcohol consumption, pneumonectomy, high intraoperative pressure index, and excessive fluid intake over the first 24 h.
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Anesthesia and analgesia · Dec 2003
Prevention of atelectasis formation during induction of general anesthesia.
General anesthesia promotes atelectasis formation, which is augmented by administration of large oxygen concentrations. We studied the efficacy of positive end-expiratory pressure (PEEP) application during the induction of general anesthesia (fraction of inspired oxygen [FIO(2)] 1.0) to prevent atelectasis. Sixteen adult patients were randomly assigned to one of two groups. Both groups breathed 100% O(2) for 5 min and, after a general anesthesia induction, mechanical ventilation via a face mask with a FIO(2) of 1.0 for another 5 min before endotracheal intubation. Patients in the first group (PEEP group) had continuous positive airway pressure (CPAP) (6 cm H(2)O) and mechanical ventilation via a face mask with a PEEP of 6 cm H(2)O. No CPAP or PEEP was applied in the control group. Atelectasis, determined by computed radiograph tomography, and analysis of blood gases were measured twice: before the beginning of anesthesia and directly after the intubation. There was no difference between groups before the anesthesia induction. After endotracheal intubation, patients in the control group showed an increase of the mean area of atelectasis from 0.8% +/- 0.9% to 4.1% +/- 2.0% (P = 0.0002), whereas the patients of the PEEP group showed no change (0.5% +/- 0.6% versus 0.4% +/- 0.7%). After the intubation with a FIO(2) of 1.0, PaO(2) was significantly higher in the PEEP group than in the control (591 +/- 54 mm Hg versus 457 +/- 99 mm Hg; P = 0.005). Atelectasis formation is prevented by application of PEEP during the anesthesia induction despite the use of large oxygen concentrations, resulting in improved oxygenation. ⋯ Application of positive end-expiratory pressure during the induction of general anesthesia prevents atelectasis formation. Furthermore, it improves oxygenation and probably increases the margin of safety before intubation. Therefore, this technique should be considered for all anesthesia induction, at least in patients at risk of difficult airway management during the anesthesia induction.
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Anesthesia and analgesia · Dec 2003
Case ReportsHyperbaric therapy for a postpartum patient with prolonged epidural blockade and tomographic evidence of epidural air.
We used the epidural technique "loss of resistance to air" to provide labor analgesia in a healthy parturient. Inadequate analgesia required epidural catheter replacement using the same technique. Delayed recovery of sensory and motor blockade postpartum necessitated computed tomography and magnetic resonance imaging studies. These revealed 4-6 mL of air in the epidural space with no evidence of thecal compression. On the advice of the neurologist, this patient underwent hyperbaric therapy 14 h after the discontinuation of the epidural infusion. The patient made a complete recovery and was discharged without neurologic sequelae. It is possible that epidural air delayed the absorption of local anesthetics as a result of a reduction in the vascular surface area. Although a cause and effect relationship between epidural air and prolonged neurological block cannot be categorically established, the use of "loss of resistance to air" technique complicated the differential diagnosis. ⋯ We report a case of prolonged motor and sensory block after labor analgesia using "loss of resistance to air" technique. The presence of epidural air on tomography resulted in the patient undergoing hyperbaric therapy. The use of loss of resistance to air technique complicated the differential diagnosis of prolonged sensory and motor block.
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Anesthesia and analgesia · Dec 2003
Randomized Controlled Trial Clinical TrialThe effect of intraoperative use of esmolol and nicardipine on recovery after ambulatory surgery.
There is controversy regarding the optimal technique for maintaining hemodynamic stability during anesthesia. We designed this prospective, randomized, double-blinded study to test the hypothesis that the technique used for maintaining hemodynamic stability during general anesthesia can influence recovery after ambulatory surgery. Forty-five healthy consenting women undergoing gynecologic laparoscopy procedures were randomly assigned to 1 of 3 treatment groups: Group 1 (control, n = 15) received normal saline 5 mL and 1 mL, followed by a saline infusion at a rate of 0.005 mL x kg(-1) x min(-1); Group 2 (n = 15) received esmolol 50 mg and saline 1 mL, followed by an esmolol infusion 5 microg x kg(-1) x min(-1); and Group 3 (n = 15) received esmolol 50 mg and nicardipine 1 mg, followed by an esmolol infusion 5 microg x kg(-1) x min(-1). The study drugs were administered after the induction of anesthesia with fentanyl 1.5 microg/kg, and propofol 2 mg/kg I.V. Tracheal intubation was facilitated with vecuronium 0.12 mg/kg I.V. Anesthesia was initially maintained with desflurane 2% end-tidal and N(2)O 67% in oxygen in all 3 groups. During surgery, the mean arterial blood pressure (MAP) was maintained within +/-15% of the baseline value by varying the study drug infusion rate and the inspired concentration of desflurane. In addition to MAP and heart rate values, electroencephalogram bispectral index values were recorded throughout the perioperative period. Recovery times and postoperative side effects were assessed. Compared with the control group, adjunctive use of esmolol and nicardipine attenuated the increase in heart rate (in Group 2) and MAP (in Group 3) after tracheal intubation. Furthermore, the use of an esmolol infusion as an adjunct to desflurane to control the acute autonomic responses during the maintenance period significantly decreased emergence times (4 +/- 2 versus 7 +/- 4 min), decreased the need for postoperative opioid analgesics (43% versus 80%), and reduced the time to discharge (209 +/- 89 versus 269 +/- 100 min). We conclude that the adjunctive use of esmolol alone or in combination with nicardipine during the induction of anesthesia reduced the hemodynamic response to tracheal intubation. Furthermore, use of an esmolol infusion as an adjuvant to desflurane-N(2)O anesthesia for controlling the acute hemodynamic responses during the maintenance period improved the recovery profile after outpatient laparoscopic surgery. ⋯ The adjunctive use of the beta-adrenergic blocker esmolol to control the acute sympathetic responses during desflurane-based anesthesia provided a more rapid awakening from anesthesia, reduced the postoperative opioid analgesic requirement, and decreased the time to discharge home after ambulatory laparoscopic surgery.