Anesthesia and analgesia
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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 Clinical TrialThe pharmacokinetics and efficacy of ropivacaine continuous wound instillation after spine fusion surgery.
Because local anesthetic continuous wound instillation has not been evaluated after spine fusion surgery, we designed this study to determine whether this technique could enhance analgesia and improve patient outcome after posterior lumbar arthrodesis. Thirty-eight patients undergoing spine stabilization were randomly divided into two groups. The M group received a postoperative baseline IV infusion of morphine plus ketorolac for 24 h, and the R group received IV saline. In both groups, a multihole 16-gauge catheter was placed subcutaneously; in the R group, the wound was infiltrated with a solution of ropivacaine 0.5% 200 mg/40 mL, and infusion of ropivacaine 0.2% 5 mL/h was maintained for 55 h. In the M group, saline infusion was given at the same rate. Pain scores were taken at rest and on passive mobilization by nurses blinded to patient analgesic treatment. The total plasma ropivacaine concentration was evaluated. Pain scores and rescue medication requirements (diclofenac and tramadol) were significantly less in the R group than in the M group. Postoperative blood loss was less and the length of hospital stay was shorter in the R group. The ropivacaine peak total plasma concentration occurred at 24 h during infusion and was within safe limits; no toxic local anesthetic side effects were observed. These results suggest that wound infiltration and continuous instillation of ropivacaine 0.2% is effective for pain management after spine stabilization surgery. ⋯ Postoperative pain after lumbar arthrodesis is related to soft tissue and muscle dissection and to manipulations and removal at the operation site. By blocking noxious stimuli from the surgical area, infiltration and wound perfusion with ropivacaine were more effective in controlling pain than systemic analgesia.
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Anesthesia and analgesia · Jan 2004
ReviewAre peripheral opioid antagonists the solution to opioid side effects?
Opioid medication is the mainstay of therapy for severe acute and chronic pain. Unfortunately, the side effects of these medications can affect patient comfort and safety, thus limiting their proven therapeutic potential. Whereas the main analgesic effects of opioids are centrally mediated, many of the common side effects are mediated via peripheral receptors. Novel peripheral opioid antagonists have been recently introduced that can block the peripheral actions of opioids without affecting centrally mediated analgesia. We review the clinical and experimental evidence of their efficacy in ameliorating opioid side effects and consider what further information might be useful in defining their role. ⋯ The major analgesic effects of opioid medication are mediated within the brain and spinal cord. Many of the side effects of opioids are caused by activation of receptors outside these areas. Recently developed peripherally restricted opioid antagonists have the ability to block many opioid side effects without affecting analgesia.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialThe effects of prolonged ambulation on labor with epidural analgesia.
Ambulation during labor is becoming more popular, although its impact on the progress of labor and on pain intensity remains unclear. We wondered whether prolonged ambulation with epidural analgesia had a possible effect on duration of labor and pain. In this prospective, randomized trial, 61 parturients with uncomplicated term pregnancies were allocated to be recumbent (n = 31) or to ambulate (n = 30). Epidural analgesia was provided with intermittent administrations of 0.08% bupivacaine-epinephrine plus 1 microg/mL of sufentanil. Of the 30 women assigned to the ambulatory group, 25 actually walked. Their ambulating time was 64 +/- 34 min (mean +/- SD), i.e., 29% +/- 16% of the first stage. There were no differences between the two groups in the length of labor and in pain visual analog scale scores. However, the ambulatory group received smaller doses of bupivacaine (6.4 +/- 2.2 mg/h versus 8.4 +/- 3.6 mg/h; P = 0.01) and of oxytocin (6.0 +/- 3.7 mUI/min versus 10.2 +/- 8.8 mUI/min; P < 0.05). A greater ability to void was also found in the ambulatory group (P < 0.01). Although the duration of labor and pain relief was unchanged, these findings support that ambulation during labor may be advantageous. ⋯ This study compared the duration of labor and pain relief between parturients receiving epidural analgesia who were ambulated or were recumbent. Whereas walking had no impact on either duration of labor or pain relief, it was associated with a reduction in both bupivacaine and oxytocin requirements.
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Anesthesia and analgesia · Jan 2004
Case ReportsPituitary apoplexy presenting as unilateral third cranial nerve palsy after coronary artery bypass surgery.
The new onset of pituitary apoplexy is a rare perioperative complication of coronary artery bypass surgery. A variety of clinical presentations of pituitary apoplexy have been reported including absence of clinical symptoms or headache, sudden deterioration of mental status, visual changes, Addisonian crisis, and ophthalmoplegia, including third cranial nerve palsy and/or ptosis. Early diagnosis and treatment usually results in excellent outcome. We report a case of pituitary apoplexy that presented with only a unilateral dilated pupil, ptosis, and vision change within 3 h after coronary artery bypass surgery. The patient recovered fully after early pituitary tumor resection and hormonal therapy. ⋯ Unilateral pupil dilation is a rare perioperative complication after coronary artery bypass surgery. We report a case of pituitary apoplexy that presented clinically as unilateral dilated pupil, ptosis, and visual loss shortly after coronary artery bypass surgery.