Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1999
Meta AnalysisThe use of nonpharmacologic techniques to prevent postoperative nausea and vomiting: a meta-analysis.
We assessed the efficacy of nonpharmacologic techniques to prevent postoperative nausea and vomiting (PONV) by systematic review. These studies included acupuncture, electroacupuncture, transcutaneous electrical nerve stimulation, acupoint stimulation, and acupressure. Of the 24 randomized trials retrieved by a search of articles indexed on the MEDLINE and EMBASE databases (1980-1997), 19 were eligible for meta-analysis. The primary outcomes were the incidence of nausea, vomiting, or both 0-6 h (early efficacy) or 0-48 h (late efficacy) after surgery. The pooled relative risk (RR) and numbers needed to treat (NNT) were calculated. In children, no benefit was found. Some results in adults were significant. Nonpharmacologic techniques were similar to antiemetics in preventing early vomiting (RR = 0.89 [95% confidence interval 0.47-1.67]; NNT = 63 [10-infinity]) and late vomiting (RR = 0.80 [0.35-1.81]; NNT = 25 [5-infinity]) in adults. Nonpharmacologic techniques were better than placebo at preventing early nausea (RR = 0.34 [0.20-0.58]; NNT = 4 [3-6]) and early vomiting in adults (RR = 0.47 [0.34-0.64]; NNT = 5 [4-8]). Nonpharmacologic techniques were similar to placebo in preventing late vomiting in adults (RR = 0.81 [0.46-1.42]; NNT = 14 [6-infinity]). Using nonpharmacologic techniques, 20%-25% of adults will not have early PONV compared with placebo. It may be an alternative to receiving no treatment or first-line antiemetics. ⋯ This systematic review showed that nonpharmacologic techniques were equivalent to commonly used antiemetic drugs in preventing vomiting after surgery. Nonpharmacologic techniques were more effective than placebo in preventing nausea and vomiting within 6 h of surgery in adults, but there was no benefit in children.
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Anesthesia and analgesia · Jun 1999
Randomized Controlled Trial Clinical TrialTransient hyperdynamic response associated with controlled hypocapneic hyperventilation during sevoflurane-nitrous oxide mask induction in adults.
We assessed hemodynamic variables during sevoflurane face mask anesthetic induction in female ASA physical status I or II patients. Anesthesia was induced with a single-breath inhalation method with 8% sevoflurane in 50% nitrous oxide in oxygen. Thirty patients were randomized either to breathe spontaneously (SB group, n = 15) or to receive controlled ventilation (CV group, n = 15) for 6 min after the loss of consciousness. Noninvasive blood pressure and heart rate (HR) were recorded at 1-min intervals. Mean +/- SD HR increased from 83+/-18 to 112+/-24 bpm at 4 min in the CV group (P < 0.001 between groups and within group compared with baseline). Mean arterial pressure increased from 97+/-9 to 106+/-26 mm Hg at 4 min in the CV group, which was significantly higher than that in the SB group (P < 0.01). In the SB group, mean arterial pressure decreased significantly, from 96+/-8 to 78+/-13 mmHg, at 6 min (P < 0.001), and HR remained unchanged. Therefore, hyperventilation should be avoided during the induction of sevoflurane anesthesia via a mask. ⋯ In this randomized, prospective study, we found that controlled hypocapneic hyperventilation delivered manually during sevoflurane/ N2O/O2 mask induction was associated with a significant transient hyperdynamic response. This kind of hemodynamic arousal can be detrimental to many patients and can be avoided by conducting sevoflurane mask induction with unassisted spontaneous breathing.
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Anesthesia and analgesia · Jun 1999
Randomized Controlled Trial Clinical TrialEpidural phenylephrine attenuates hypotension induced by alkalinized lidocaine epidural anesthesia.
In this double-blinded, randomized study, we examined the hemodynamic effects of lumbar epidural injection of alkalinized lidocaine with phenylephrine in 81 patients undergoing inguinal herniorrhaphy. Patients assigned to four equal groups received 20 mL of alkalinized lidocaine (17 mL of 2% lidocaine + 3 mL of 7% sodium bicarbonate) with one of four doses of phenylephrine: 0 (Group 1), 50 (Group 2), 100 (Group 3), or 200 microg (Group 4) injected via a lumbar epidural catheter. Blood pressure, heart rate, and skin temperature on the foot were recorded every 5 min for 1 h after injection and were compared among groups. Hypotension was defined as mean arterial pressure < 80% of baseline. The incidence of hypotension was 45%, 55%, 35%, and 15% in Groups 1-4, respectively. Patients in Group 4 showed the smallest reduction in blood pressure compared with Groups 1 and 2 (one-sided Fisher's exact test, P < 0.05). We conclude that the 200-microg dose of epidural phenylephrine (1:100,000 concentration) reduced the incidence of hypotension after epidural anesthesia with alkalinized lidocaine. ⋯ Hypotension after epidural anesthesia is common in general clinical practice. Phenylephrine administered epidurally in combination with alkalinized lidocaine may reduce the incidence of hypotension.
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Anesthesia and analgesia · Jun 1999
Randomized Controlled Trial Clinical TrialEpidural ropivacaine for the initiation of labor epidural analgesia: a dose finding study.
The purpose of our study was to determine the lowest concentration of ropivacaine that offers pain relief for the initiation of labor epidural analgesia. Women in active labor were enrolled in this prospective, randomized, double-blinded study to receive either ropivacaine 0.20% (Group I), ropivacaine 0.15% (Group II), or ropivacaine 0.10% (Group III). After placement of the epidural catheter, 13 mL of the study medication was administered. Fifteen minutes later, the adequacy of analgesia was assessed. If the woman reported that her degree of analgesia was not adequate, an additional 5 mL of the study medication was given, the degree of pain relief was reassessed 15 min later, and the study was concluded. A sequential study design was used to assess the success rates. We found that 26 of 28 (93%) women in Group I had adequate analgesia, compared with only 18 of 28 (64%) in Group II (P = 0.014) and 4 of 12 (33%) in Group III (P = 0.003). We conclude that ropivacaine 0.20% offers adequate analgesia significantly more often than either ropivacaine 0.15% or ropivacaine 0.10%. If one selects ropivacaine as the sole local anesthetic for the initiation of labor epidural analgesia, the minimal concentration should be 0.20%. ⋯ The lowest effective concentration of ropivacaine for the initiation of labor epidural analgesia has not been determined. We found that ropivacaine 0.20% offers adequate analgesia significantly more often than either ropivacaine 0.15% or ropivacaine 0.10%. If one selects ropivacaine as the sole local anesthetic for the initiation of labor epidural analgesia, the minimal concentration should be 0.20%.
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Anesthesia and analgesia · Jun 1999
Clinical TrialTissue heat content and distribution during and after cardiopulmonary bypass at 17 degrees C.
We measured afterdrop and peripheral tissue temperature distribution in eight patients cooled to approximately 17 degrees C during cardiopulmonary bypass and subsequently rewarmed to 36.5 degrees C. A nasopharyngeal probe evaluated trunk and head temperature and heat content. Peripheral tissue temperature (arm and leg temperature) and heat content were estimated using fourth-order regressions and integration over volume from 30 tissue and skin temperatures. Peripheral tissue temperature decreased to 19.7+/-0.9 degrees C during bypass and subsequently increased to 34.3+/-0.7 degrees C during 104+/-18 min of rewarming. The core-to-peripheral tissue temperature gradient was -5.9+/-0.9 degrees C at the end of cooling and 4.7+/-1.5 degrees C at the end of rewarming. The core-temperature afterdrop was 2.2+/-0.4 degrees C and lasted 89+/-15 min. It was associated with 1.1+/-0.7 degrees C peripheral warming. At the end of cooling, temperatures at the center of the upper and lower thigh were (respectively) 8.0+/-5.2 degrees C and 7.3+/-4.2 degrees C cooler than skin temperature. On completion of rewarming, tissue at the center of the upper and lower thigh were (respectively) 7.0+/-2.2 degrees C and 6.4+/-2.3 degrees C warmer than the skin. When estimated systemic heat loss was included in the calculation, redistribution accounted for 73% of the afterdrop, which is similar to the contribution observed previously in nonsurgical volunteers. ⋯ Temperature afterdrop after bypass at 17 degrees C was 2.2+/-0.4 degrees C, with approximately 73% of the decrease in core temperature resulting from core-to-peripheral redistribution of body heat. Cooling and rewarming were associated with large radial tissue temperature gradients in the thigh.