Warm air sensation for assessment of block after spinal anaesthesia.
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We have evaluated a new method of assessing dermatomal sensory levels after regional anaesthesia based on warm sensation. Sensory levels were assessed in 30 patients after spinal anaesthesia using a respiratory gas humidifier, adapted to deliver a constant flow of warm air at 40 +/- 0.2 degrees C. This was compared with the cold sensation from ethyl chloride spray. The frequency distribution of the dermatomal differences showed 96.6% of the comparisons were between +1 and -1 dermatomes. The median difference in dermatomal levels between the two methods of assessment was 0 (interquartile range 0-1) (P = 0.65). We conclude that the warm air method compares favourably with ethyl chloride spray and both can be used interchangeably. (+info)
Preparation for regional anaesthesia induces changes in thrombelastography.
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The effects of crystalloid and colloid infusions on coagulation measured by thrombelastography (TEG) present a confused picture. The influence of environmental factors may explain the disparity between previous studies. We studied two groups of 20 women presenting at term for elective Caesarean section. In the first group, TEG analysis was performed before and after infusion of Gelofusine 500 ml over 15 min. The second group was treated in the same way except that subjects did not receive fluid. We found significant changes in r and k values in both groups, suggesting enhanced coagulation. As hypercoagulable changes were also seen in the group that did not receive fluid preload, the hypothesis that moderate haemodilution causes hypercoagulability must be questioned. The influence of environmental factors can explain differences reported between in vivo and in vitro studies. (+info)
Acupressure and prevention of nausea and vomiting during and after spinal anaesthesia for caesarean section.
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The efficacy of acupressure at the P6 point in the prevention of nausea and vomiting during and after Caesarean section was studied. A double-blind, randomized controlled study of acupressure vs placebo was designed. Ninety-four patients scheduled for Caesarean section were included. The anaesthetic technique and postoperative analgesia were standardized. The use of acupressure reduced the incidence of nausea or vomiting from 53% to 23% compared with placebo (95% confidence interval (CI) 0.34-0.25; P = 0.002) during the operation and from 66% to 36% compared with placebo (95% CI 0.34-0.19; P = 0.003) after the operation. Other variables were similar between the groups. (+info)
Extent of hyperbaric spinal anesthesia influences the duration of spinal block.
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BACKGROUND: The influence of spread of spinal anesthesia on the duration of spinal blockade has been suggested but never investigated specifically. Because elimination of local anesthetic from subarachnoid space is probably dependent of the surface available for its diffusion and vascular absorption, the current study was designed to evaluate the hypothesis that with a same dose of hyperbaric bupivacaine, a higher anesthetic level would result in a shorter duration of spinal blockade than a lower level. METHODS: Three milliliters (15 mg) of hyperbaric bupivacaine, 0.5%, was injected intrathecally in 40 patients classified as American Society of Anesthesiologists physical status I or H scheduled for lower limb surgery during spinal anesthesia. To obtain significantly different anesthetic levels, the patients were positioned randomly either horizontally or with the torso elevated 30. Regression of sensory level and motor blockade, the appearance of pain at the operative site, and hemodynamic changes were evaluated. RESULTS: The maximum cephalad spread of sensory blockade (expressed as the median with ranges in parentheses) was significantly higher in the horizontal group than in the group with 30-degree elevation of the torso, i.e., T3.5 (T1-T9) versus T10 (T6-L1), with respectively significantly faster regression times (mean inverted question mark SD) by two segments (216 inverted question mark 46 mm vs. 253 inverted question mark 64 mm) and to segment L4 (269 inverted question mark 53 mm i s. 337 inverted question mark 58 mm), as well as shorter time to complete motor blockade recovery (173 inverted question mark 34 mm i s. 233 inverted question mark 58 mm) and faster appearance of pain at the operative site (221 inverted question mark 68 mm vs. 271 inverted question mark 56 mm). CONCLUSION: The results indicate that with the same dose of hyperbaric bupivacaine, the duration of spinal blockade is longer in patients with restricted spread. (+info)
Caesarean section for placenta praevia: a retrospective study of anaesthetic management.
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A retrospective survey of anaesthesia for Caesarean section (CS) for placenta praevia was performed, covering the period between January 1, 1984 and December 31, 1998. Three hundred and fifty consecutive cases of placenta praevia were identified. Overall a regional technique was used 60% of the time. Five women had a placenta accreta which required Caesarean hysterectomy: one had general anaesthesia (GA) throughout and four initially received a single-shot spinal injection. Of these latter four cases, two were converted to GA during the hysterectomy and two continued with spinal anaesthesia throughout. Two other women (both GA), suffered postoperative thrombotic episodes (one pulmonary embolus and one cerebral thrombosis) but made full recoveries. Control of blood pressure when using regional anaesthesia (RA), even in the presence of considerable haemorrhage, was not a problem. Statistical regression models indicated that RA was associated with a significantly reduced estimated blood loss and reduced need for blood transfusion. This retrospective survey finds no data to support the much quoted aphorism that RA is contraindicated for CS in the presence of placenta praevia. (+info)
Subarachnoid meperidine (Pethidine) causes significant nausea and vomiting during labor. The Duke Women's Anesthesia Research Group.
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BACKGROUND: The combined spinal-epidural (CSE) technique using bupivicaine-fentanyl has become an established method of pain control during parturition. One limitation is the relatively short duration of effective analgesia produced by bupivicaine-fentanyl. In contrast, subarachnoid meperidine has been shown to provide a long duration of anesthesia in nonobstetric patients. Therefore, the authors tested the hypothesis that subarachnoid meperidine produces a significant increase in the duration of analgesia compared with bupivicaine-fentanyl. METHODS: Based on a power analysis of preliminary data, the authors intended to recruit 90 patients for the study, randomized to three groups: 2.5 mg bupivicaine-25 microg fentanyl, 15 mg meperidine, or 25 mg meperidine. However, after enrolling 34 patients, the study was discontinued because of a significant increase in nausea or vomiting in the study patients. RESULTS: Nausea or vomiting was substantially increased in both meperidine groups compared with the bupivicaine-fentanyl group: 16 with nausea or vomiting in the meperidine groups (n = 21), compared with 1 in the bupivicaine-fentanyl group (n = 11), P = 0.0011. The mean duration of analgesia provided by 25 mg meperidine was 126 +/- 51 min, compared with 98 +/- 29 min for bupivicaine-fentanyl and 90 +/- 67 min for 15 mg meperidine. These data were not significant (P = 0.27). CONCLUSIONS: Although intrathecal meperidine could potentially prolong subarachnoid analgesia during labor, its use was associated with a significant incidence of nausea or vomiting. These data do not support the use of subarachnoid meperidine in doses of 15 or 25 mg for labor analgesia. (+info)
Sedation during spinal anesthesia.
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BACKGROUND: Central neuraxial anesthesia has been reported to decrease the dose of both intravenous and inhalational anesthetics needed to reach a defined level of sedation. The mechanism behind this phenomenon is speculated to be decreased afferent stimulation of the reticular activating system. The authors performed a two-part study (nonrandomized pilot study and a subsequent randomized, double-blind, placebo-controlled study) using the Bispectral Index (BIS) monitor to quantify the degree of sedation in unmedicated volunteers undergoing spinal anesthesia. METHODS: Twelve volunteers underwent BIS monitoring and observer sedation scoring (Observer's Assessment of Alertness/Sedation Scale [OAA/S]) before and after spinal anesthesia with 50 mg hyperbaric lidocaine, 5%. Subsequently, 16 volunteers blinded to the study were randomized to receive spinal anesthesia with 50 mg hyperbaric lidocaine, 5% (n = 10) or placebo (n = 6) and underwent BIS and OAA/S monitoring. RESULTS: In part I, significant changes in BIS scores of the volunteers occurred progressively (P = 0.003). The greatest variations from baseline BIS measurement occurred at 30 and 70 min. In part II, there were significant decreases in OAA/S and self-sedation scores for patients receiving spinal anesthesia versuscontrol patients (P = 0.04 and 0. 01, respectively). The greatest decrease in OAA/S scores occurred at 60 min. BIS scores were similar between groups (P = 0.4). CONCLUSIONS: Spinal anesthesia is accompanied by significant sedation progressively when compared with controls as measured by OAA/S and self-sedation scores. This effect was not related to block height. The late sedation observed by OAA/S at 60 min may indicate a second mechanism of sedation, such as delayed rostral spread of local anesthetics. BIS was not a sensitive measure of the sedation associated with spinal anesthesia in the randomized, blinded portion of this study. (+info)
BACKGROUND: Intrathecal neostigmine causes analgesia by inhibiting the breakdown of acetylcholine. Experimental data suggest that the production of endogenous nitric oxide is necessary for tonic cholinergic inhibition of spinal pain transmission. The purpose of this study was to determine whether association of transdermal nitroglycerine would enhance analgesia from a low dose of intrathecal neostigmine in patients undergoing gynecologic surgery during spinal anesthesia. METHODS: Forty-eight patients were randomized to one of four groups. Patients were premedicated with use of 0.05-0.1 mg/kg intravenous midazolam and received 15 mg bupivacaine plus 1 ml test drug intrathecally (saline or neostigmine, 5 microgram). Twenty to 30 min after the spinal puncture, a transdermal patch of either 5 mg nitroglycerin or placebo was applied. The control (Con) group received spinal saline and transdermal placebo. The neostigmine group received spinal neostigmine and transdermal placebo. The nitroglycerin group received spinal saline and a transdermal nitroglycerine patch. Finally, the neostigmine-nitroglycerin group received spinal neostigmine and transdermal nitroglycerine. Pain and adverse effects were evaluated using a 10-cm visual analog scale. RESULTS: Patients in the groups were similar regarding age, weight, height, and American Society of Anesthesiologists status. Sensory level to pin prick at 10 min, surgical duration, anesthetic duration, and visual analog scale score for pain at the time of administration of first rescue medication were statistically the same for all groups. The time to administration of first rescue analgesic (min) was longer in the neostigmine-nitroglycerin group (550 min; range, 458-1,440 min; median, 25-75th percentile) compared with the other groups (P < 0.001). The neostigmine-nitroglycerin group required fewer rescue analgesics in 24 h than did the control group (P < 0.0005), whereas the neostigmine group required less analgesics compared with the control group (P < 0.02). The incidence of perioperative adverse effects (nausea, vomiting, headache, back pain) was similar among groups (P > 0.05). CONCLUSION: Although neither intrathecal 5 microgram neostigmine alone nor transdermal nitroglycerine alone (5 mg/day) delayed the time to administration of first rescue analgesics, the combination of both provided an average of 14 h of effective postoperative analgesia after vaginoplasty, suggesting that transdermal nitroglycerin and the central cholinergic agent neostigmine may enhance each other's antinociceptive effects at the dose studied. (+info)