Comparison of renal function under deliberate hypotension during epidural plus light-enflurane anesthesia and during enflurane anesthesia

We compared the effects of deliberate hypotension induced with trimethaphan on renal function and renal tubular damage under combined epidural and light-enflurane anesthesia (epidural group) and enflurane anesthesia alone (enflurane group). The mean arterial blood pressure was maintained at 50–55 mm Hg for 2.5 h in both groups using continuous infusion of trimethaphan. The urine volume and free water clearance were significantly greater in the epidural group than in the enflurane group [1.8±1.8 (SD)vs 0.4±0.3 ml·kg⁻¹·h⁻¹ and 0.81±1.30vs −0.15±0.22 ml·min⁻¹, respectively] (P<0.05). The creatinine clearance and fractional sodium excretion rate did not differ significantly between the two groups. Urinary excretion of norepinephrine was significantly less in the epidural group than in the enflurane group (P<0.05); however, epinephrine excretion did not differ. Urinary excretion ofN-acetyl-β-d-glucosaminidase was significantly less in the epidural group than in the enflurane, group (4.2±2.5vs 12.2±4.6 U·g⁻¹ CR) (P<0.01). The plasma antidiuretic hormone concentration was significantly lower in the epidural group compared to the enflurene group (13±23vs 57±42 pg·ml⁻¹) (P<0.05). No significant difference in plasma atrial natriuretic peptide concentration was found between the groups. We conclude that renal function during trimethaphan-induced hypotension is better maintained under epidural plus light-enflurane anesthesia than under enflurane anesthesia alone.     

Hypotension associated with systemic aggregated anaphylaxis is not attenuated by a selective endothelin-A receptor antagonist,BQ 610, in rabbits in vivo

Purpose. The present study was done to investigate the role of endothelin-1 (ET-1) in hypotension and bronchospasm provoked by anaphylaxis in rabbits in vivo. Methods. Forty-five rabbits sensitized to horse serum were randomly allocated to five groups: Group 1 (n = 10) received 0.5 nmol·kg⁻¹ of ET-1; Group 2 (n = 10) received 0.5 nmol·kg⁻¹ of ET-1 and 200 nmol·kg⁻¹ of a selective ET_A receptor antagonist, BQ 610, without anaphylaxis; Group 3 (n = 5) received 200 nmol·kg⁻¹ of BQ 610 alone without anaphylaxis; Group 4 (n = 10) received normal saline alone before being antigen challenged to induce anaphylaxis; Group 5 (n = 10) received 200 nmol·kg⁻¹ of BQ 610 before antigen challenge. Results. Mean arterial pressure (MAP) values were significantly different between Groups 1 and 2. Heart rate (HR), central venous pressure (CVP), dynamic pulmonary compliance (C_dyn), and pulmonary airway resistance (R_L) did not differ significantly between Groups 1 and 2. MAP values were significantly decreased compared with baseline in both Groups 4 and 5; however, the values were not significantly different between two groups. CVP values were significantly different between Groups 4 and 5 only at the 15-min time point following antigen challenge. HR, R_L, and C_dyn values were not significantly different between Groups 4 and 5, nor were the survival rates. Conclusion. BQ 610 does not improve hypotension or survival rates in systemic aggregated anaphylactic rabbits in vivo, implying that circulating ET-1 may not play an important role in anaphylaxis, although direct proof of production of circulating ET-1 or activation of ET_A receptors is lacking in this study. Received: October 15, 2001 / Accepted: August 20, 2002 Address correspondence to: T. Kawakami     

Systemic clonidine activates neurons of the dorsal horn, but not the locus ceruleus (A6) or the A7 area, after a formalin test: the importance of the dorsal horn in the antinociceptive effects of clonidine

Purpose In order to clarify the principal site for the antinociceptive effects of clonidine, we investigated the nociceptive behavior and neural activity (c-fos staining) of the dorsal horn (DH), locus ceruleus (LC), and A7 area after a formalin test in normal saline- or clonidine-injected rats. Methods Thirty-six rats were divided into 6 groups as follows: formalin test + saline (FS); formalin test + clonidine (1 mg·kg⁻¹) (FC1); formalin test + clonidine (10 mg·kg⁻¹) (FC10); saline (S); clonidine (1 mg·kg⁻¹) (C1); and clonidine (10 mg·kg⁻¹) (C10). Normal saline or clonidine was injected intraperitoneally 30 min before the formalin test. In the FS, FC1, and FC10 groups, 10% formalin was injected into the left rear paw. All rats were killed 2.5 h after normal saline or clonidine injection. Sections of the lumbar spinal cord, LC, and A7 area were processed for c-fos immunohistochemistry using the avidin–biotin peroxidase complex method. To evaluate the sedative effects of clonidine, we investigated the loss of righting reflex (LORR) for 90 min in 6 other rats as follows: clonidine (1 mg·kg⁻¹) (n = 3) and clonidine (10 mg·kg⁻¹) (n = 3). Results The FC10 group showed fewer nociceptive behaviors and higher c-fos expression in the DH, but not in the A7 area, as well as lower c-fos expression in the LC than rats in the FS and FC1 groups (P < 0.05). The C10 group showed lower c-fos expression in the LC than that of rats in the S and C1 groups (P < 0.05). No rats exhibited LORR. Conclusion The antinociceptive effects of clonidine might be mediated primarily by neural activity in the DH.     

The degree of newly emerging mitral regurgitation during off-pump coronary artery bypass is predicted by preoperative left ventricular function

Purpose During off-pump coronary artery bypass (OPCAB), the displacement of the heart causes mitral regurgitation. We hypothesized that patients with impaired left ventricle (LV) function would be more prone to develop mitral regurgitation, due to further LV end-diastolic pressure elevation and mitral annulus distortion. Therefore, in this study, we examined the relationship between LV function and the severity of mitral regurgitation. Methods We studied 41 patients undergoing elective OPCAB. LV function was evaluated by LV ejection fraction (LVEF), serum brain natriuretic peptide (BNP) levels, the Tei index (myocardial performance index) and mitral inflow propagation velocity (Vp). Results Among all of the anastomoses performed mitral regurgitation was most severe during anastomosis of the left circumflex artery (LCX) territory (P < 0.001). Twenty-five patients (61%) had no to mild mitral regurgitation during anastomosis of the LCX territory (M-MR group) and 16 patients (39%) had moderate to severe mitral regurgitation during anastomosis of the LCX territory (S-MR group). There were significant differences between these groups in preoperative serum BNP levels (median, 26 pg·ml⁻¹ interquartile range [IQR, 14 to 75 pg·ml⁻¹] versus median, 173 pg·ml⁻¹ [IQR, 91 to 296 pg·ml⁻¹]; P < 0.001), Tei index values (median, 0.35; [IQR, 0.27 to 0.41] versus median, 0.53 [IQR, 0.47 to 0.57]; P < 0.001), and Vp (median, 63 cm·s⁻¹; [IQR, 57 to 72 cm·s⁻¹] versus median, 47 cm·s⁻¹; [IQR, 40 to 57 cm·c⁻¹]; P = 0.008), while there was no significant difference in LVEF between the patients in the M-MR group and those in the S-MR group. Conclusion Preoperative LV dysfunction is a predictor of severe mitral regurgitation during OPCAB. When poor LV function is suggested, it is necessary to be prepared for further hemodynamic deterioration caused by mitral regurgitation.     

Effect of peak inspiratory flow on gas exchange, pulmonary mechanics, and lung histology in rabbits with injured lungs

Purpose The aim of this study was to evaluate, using a rabbit model, the little-known effect of different levels of peak inspiratory flow on acutely injured lungs. Methods Fourteen male rabbits (body weight, 2711 ± 146 g) were anesthetized and their lungs were injured by alveolar overstretch with mechanical ventilation until Pa_O2 was reduced below 300 mmHg. Injured animals were randomly assigned to: the P group—to receive pressure-regulated volume-control ventilation (PRVCV; n = 7); and the V group—to receive volume-control ventilation (VCV; n = 7). Other ventilator settings were: fraction of inspired oxygen (FI_O2), 1.0; tidal volume, 20 ml·kg⁻¹; positive end-expiratory pressure (PEEP) 5 cmH₂O; and respiratory rate, 20 min⁻¹. The animals were thus ventilated for 4 h. Throughout the protocol, ventilatory parameters and blood gas were measured every 30 min. After the protocol, the lung wet-to-dry ratio and histological lung injury score were evaluated in the excised lungs. Results Throughout the protocol, peak inspiratory flow and mean inspiratory flow values in the P group were significantly higher than those in the V group (26.7 ± 5.0 l·min⁻¹ vs 1.2 ± 0.2 l·min⁻¹, and 4.3 ± 0.3 l·min⁻¹ vs 1.1 ± 0.1 l·min⁻¹; P < 0.05). The wet-to-dry ratio in the P group was also significantly higher than that in the V group (7.7 ± 0.9 vs 6.3 ± 0.5; P < 0.05). More animals in the P group than in the V group had end-of-protocol Pa_O2/FI_O2 ratios below 200 mmHg (43% vs 0%; P = 0.06). Conclusion In rabbits with injured lungs, high peak inspiratory flow with high tidal volume (V_T) reduces the Pa_O2/FI_O2 ratio and increases the lung wet-to-dry ratio.     

Effects of olprinone on hepatosplanchnic circulation and mitochondrial oxidation in a porcine model of endotoxemia

Purpose This study was performed in order to assess the effects of olprinone, a phosphodiesterase III inhibitor, on hepatic oxygen delivery (DO₂H), oxygen consumption (VO₂H), and mitochondrial oxidation in the liver of a porcine endotoxemia model. Methods Fourteen pigs received continuous infusion of endotoxin via the portal vein for 240 min. From t = 150 to t = 240 min, animals were randomly divided into two groups to receive saline (control [CONT]; n = 7), or olprinone (OLP; n = 7) via the central vein. Results In the OLP group, prior to olprinone treatment at 150 min, endotoxin induced significant decreases in the cardiac index (CI; from 120 ± 31 to 65 ± 13 ml·kg⁻¹·min⁻¹; P < 0.01) and DO₂H (from 3.58 ± 0.81 to 1.55 ± 0.49 ml·kg⁻¹·min⁻¹; P < 0.01), while VO₂H was maintained. After administration of olprinone (from t = 150 to t = 240 min), CI was unchanged, while DO₂H increased from 1.55 ± 0.49 to 1.93 ± 0.38 ml·kg⁻¹·min⁻¹ (P < 0.01) and VO₂H increased from 0.42 ± 0.28 to 0.69 ± 0.38 ml·kg⁻¹·min⁻¹ (P < 0.01). At t = 240 min, the oxidation level of cytochrome aa3 was significantly higher in the OLP group than in the CONT group (OLP, 66.2 ± 19.3% vs CONT, 26.4 ± 17.3%; P < 0.01). Conclusion Our data for this porcine endotoxemia model suggest that olprinone may have beneficial therapeutic effects in restoring not only systemic and hepatic circulation but also mitochondrial oxidation in the liver.     

Prevention of postoperative nausea and vomiting in children following adenotonsillectomy,using tropisetron with or without low-dose dexamethasone

Purpose Postoperative nausea and vomiting (PONV) after adenotonsillectomy in children is, in spite of the prophylactic administration of tropisetron, still a frequent event. The aim of this study was to evaluate the benefit of the additional systemic administration of low-dose dexamethasone (0.15 mg·kg⁻¹) for the prevention of PONV. Methods With hospital ethics committee approval, we investigated children undergoing adenotonsillectomy receiving tropisetron (0.1 mg·kg⁻¹; maximum dose, 2 mg) or tropisetron (0.1 mg·kg⁻¹; maximum dose, 2 mg) plus dexamethasone (0.15 mg·kg⁻¹; maximum dose, 6 mg) intraoperatively. The incidence of vomiting episodes and the need for postoperative analgesics were recorded. Patient data were analyzed using the t-test and the χ² test (significance level of P = 0.05). Data values are means ± SD. Results Ninety children (39 girls and 51 boys), aged 5.6 ± 2.8 years and weighing 21.9 ± 8.8 kg, were enrolled in the study. The overall incidence of vomiting was 38.9% within the first 24 h (67 vomiting events) and 44.4% within 48 h postoperatively (87 vomiting events). The incidence of vomiting in the tropisetron-only group was 53.3% (24/45) at 24 h and 60% (27/45) at 48 h (24 h: P < 0.001 and 48 h: P = 0.04) and 24.4% (11/45) at 24 h and 28.9% (13/45) at 48 h in the tropisetron-dexamethasone group. The need for postoperative nalbuphine was double in patients treated with tropisetron-dexamethasone (0.61 mg ± 0.36 mg·kg⁻¹·48 h⁻¹) compared to that in patients receiving only tropisetron (0.31 mg ± 0.28 mg·kg⁻¹·48 h⁻¹; P < 0.0001). Conclusion A low-dose bolus of dexamethasone (0.15 mg·kg⁻¹) in combination with tropisetron, compared to tropisetron alone, considerably reduced the incidence of vomiting in children following pediatric adenotonsillectomy.     

Nitrous oxide can enhance the hypnotic effect, but not the suppression of spinal motor neuron excitability by propofol in humans

Purpose We investigated whether nitrous oxide can enhance the suppressive effect of propofol on spinal motor neuron excitability in humans. Methods Sixteen adult patients were prospectively randomly assigned to be given either propofol alone (group P; n = 8) or a supplement of 66% nitrous oxide with propofol (group PN; n = 8) for intraoperative sedation. Propofol was administered by a target-controlled infusion system to maintain sequentially increasing plasma propofol concentrations (Cpt) of 0.5, 0.8, 1.0, 1.3, 1.5 and 1.8 μg·ml⁻¹ in all patients. Assessment of the patient's level of sedation in both groups was performed with the Wilson Sedation Scale (WSS). F-wave analysis on the left abductor pollicis brevis muscle was carried out for the assessment of spinal motor neuron excitability at each plasma propofol concentration. Results Significant differences in the WSS scores between group P and group PN were observed at 0.8, 1.0, 1.3, and 1.5 μg·ml⁻¹ of Cpt (group P < group PN; P < 0.01). Cpt greater than 1.0 μg·ml⁻¹ significantly reduced F-wave persistence in a concentration-dependent manner, and the ICpt 50 and ICpt 95 values for plasma propofol concentration (plasma propofol concentrations that produced 50% and 95% inhibition of the baseline, respectively) were 1.05 and 1.95 μg·ml⁻¹ in group P, and 1.07 and 2.14 μg·ml⁻¹ in group PN, respectively. Conclusion These results suggest that nitrous oxide can enhance the hypnotic effect, but not the suppression of spinal motoneuron excitability by propofol in humans at clinical levels of Cpt.     

Association between height loss and bone loss, cumulative incidence of vertebral fractures and future quality of life: the Miyama study

Introduction The study aimed to clarify associations between height loss, bone loss and the quality of life (QOL) score among general inhabitants of Miyama, a rural Japanese community. This population-based epidemiological study was conducted in Miyama, a village located in a mountain area in Wakayama Prefecture, Japan. Methods A list of all inhabitants comprising 1,543 inhabitants (716 men, 827 women) born in this village between 1910–1949 was compiled. From the above whole cohort, a subcohort to measure bone mineral density (BMD) was recruited, consisting of 400 participants, divided into four groups of 50 men and 50 women each, and stratified into age decades by decade of birth-year (1910–1919, 1920–1929, 1930–1939 or 1940–1949). BMD measurement, physical measurements of height (cm) and body weight (kg) were taken, and body mass index (BMI; kg/m²) were calculated. BMD and anthropometric measurements were repeated on the same participants at 3, 7 and 10 years after baseline measurement (1993, 1997 and 2000). Results and discussion Among 299 of 400 participants, changes in height over 10 years for men in their 40s, 50s, 60s and 70s were −0.7 cm, −0.5 cm, −1.2 cm and −1.5 cm, respectively, compared with −0.7 cm, −1.4 cm, −2.1 cm and −3.7 cm in women, respectively. No significant relationships between change in height and rate of change in BMD at the lumbar spine and femoral neck after adjustment for age in men (lumbar spine, β = 0.058, standard error of the mean (SE) = 0.031, P = 0.501, R² = 0.038; femoral neck, β = 0.100, SE = 0.038, P = 0.228, R² = 0.121) were identified. By contrast, among women, a significant positive association was identified between height change and change rate of BMD at the lumbar spine after adjusting for age (β = 0.221, SE = 0.039, P = 0.012, R² = 0.069), while no significant relationship was found between height change and change rate at the femoral neck (β = 0.107, SE = 0.039, P = 0.229, R² = 0.048). No significant relationship was noted between vertebral fractures (VFx) and height at baseline in men and women (men: odds ratio (OR) 0.93, 95% confidence interval (CI) 0.81–1.05, P = 0.24; women: OR 0.97, 95% CI 0.87–1.08, P = 0.58) or between VFx and height loss (men: OR 1.31, 95% CI 1.00–1.71, P = 0.051; women: OR 1.20, 95% CI 0.94–1.53, P = 0.14). In both men and women, no significant relationship was identified between utility of the EuroQol EQ5D questionnaire and height at baseline (men: β = −0.148, SE = 0.003, P = 0.202, R² = 0.076; women: β = 0.127, SE = 0.004, P = 0.235, R² = 0.048), and height change (men: β = −0.078, SE = 0.008, P = 0.452, R² = 0.065; women: β = 0.053, SE = 0.010, P = 0.608, R² = 0.038).     

Propofol infusion for sedation during spinal anesthesia

Purpose The dose and time course of propofol infusion required to induce rapid sedation without oversedation during spinal anesthesia were investigated. Methods Forty patients scheduled for spinal and epidural anesthesia were studied. After premedication with intramuscular midazolam 0.04 mg·kg⁻¹, an epidural catheter was inserted, followed by spinal anersthesia at L4-L5 with 0.5% hyperbaric tetracaine with epinephrine. The infusion of propofol was started with 10 mg·kg⁻¹·h⁻¹ and was decreased to 5 mg·kg⁻¹·h⁻¹ at spontaneous eye closure. According to the increase or decrease of the sedation level, the infusion does was decreased or increased to half or twice the initial dose, respectively, to keep the Observer's Assessment of Alertness Sedation (OAAS) score at 3 or 4. Results Eye closure was observed at 1.0 ± 0.4 min after the start of insusion. The maintenance insusion dose to keep the OAAS score at 3 or 4 was about 2.5 mg·kg⁻¹·h⁻¹. Conclusion Propofol infusion, starting with 10 mg·kg⁻¹·h⁻¹, decreasing to 5 mg·kg⁻¹·h⁻¹ after 1 minute, and then decreasing to 2.5 mg·kg⁻¹·h⁻¹ after another min induced rapid onset of sedation and kept the OAAS score at 3 or 4 during spinal anesthesia.     

Epidural ropivacaine infusion for the treatment of pain following axillary muscle-sparing thoracotomy: a dose-evaluation study

Purpose We aimed to investigate the optimal dose of continuous epidural ropivacaine for effective analgesia with minimal side effects after axillary muscle-sparing thoracotomy. Methods Sixty patients undergoing thoracic surgery via the axillary approach were studied. Patients were given continuous epidural ropivacaine at 6 (group R-6), 9 (group R-9), 12 (group R-12) or 18 mg·h⁻¹ (group R-18) in a randomized double-blinded fashion after surgery. All of the patients received nonsteroidal anti-inflammatory drugs (NSAIDs) every 6 h for 24 h postoperatively. Pain intensity was assessed under three conditions (at rest, on moving, and while coughing), at 4, 8, 16, 24, and 48 h after surgery, and the extent of sensory block was evaluated at the same time points. The ability of a patient to walk unaided was assessed at 24 and 48 h after surgery. Results Pain intensity at rest and coughing was significantly higher in group R-6 than in the other groups at 16 h after surgery. Pain intensity during moving was significantly greater in group R-6 than in groups R-12 and R-18 at 16 h after surgery. Group R-18 exhibited a significantly greater extent of sensory block than the other groups. The number of patients who were not able to walk unaided 24 h after surgery was significantly greater in group R-18. There were no significant differences in the incidences of side effects among the groups. Conclusion Our results showed that epidural analgesia using ropivacaine, at 12 mg·h⁻¹, provided the best analgesia with few side effects.     

Epidural cooling for selective brain hypothermia in porcine model

Summary Background. Hypothermia has been shown to be neuroprotective in many animal models and several human trials of brain ischemic and trauma. However systemic hypothermia may result in fatal complications. This study was undertaken to test epidural cooling as a new method of inducing selective brain hypothermia. Method. Six adult swine (mean mass, 33.8 ± 3.6 kg) were studied. Anesthesia was maintained with pentobarbital sodium (25 mg kg⁻¹, i.v.) and pancuronium bromide (0.5 mg kg⁻¹ h⁻¹, i.v.). Five probes were placed in the rectum, deep brain, brain surface, epidural space, and room air for temperature monitoring respectively. Epidural cooling was performed using cold-saline (4 °C) perfusion into the epidural space through a flexible double-lumen catheter. The dripping speed of cold saline was controlled to maintain the target temperature. The changes of the epidural space pressure, complete blood counts, basic metabolic panels, tests for fibrinolysis and coagulation status were monitored to assess hypothermia-induced changes. Findings. Following the epidural cooling perfused with cold-saline (4 °C) at mean dripping speed of 720 ml per hour, the local brain surface temperature could decrease rapidly to 17.3–21.6 °C within one minute, and deep brain temperature decreased to 27.2–29.7 °C within 5 minutes. The target temperatures were easily controlled by the dripping speed of cold saline (from mild to deep hypothermia). The rectal temperature was maintained at normal range within 6 perfusion hours. No arrhythmia was observed, and all hematological variables were within the normal range for swine. No increased intracranial pressure was induced by the cooling method. Conclusions. The data demonstrate that epidural space cooling was technically feasible and useful for selective brain hypothermia, and the target temperatures are easily controlled. The induction of hypothermia was rapid and maintained for a long period of time, whereas the body temperature was maintained within the normal range and without hemodynamic instability.     

Randomized cross-over trial comparing albumin and frusemide infusions in nephrotic syndrome

The contribution of hypoalbuminemia to impaired diuretic responsiveness can be overcome by administering larger doses of loop diuretics. However, the clinical efficacy of the combination of loop-acting diuretics with human albumin remains controversial. In the study reported here, 16 children with nephrotic syndrome and refractory edema were randomized in a cross-over trial to receive either the combination of 20% human albumin and frusemide infusion (HA+FU infusion group) or frusemide infusion alone (FU infusion group). At the end of study, median urine volume was 3.27 [95% confidence interval (CI) 2.04–4.50] ml/kg per hour in the HA+FU infusion group and 1.33 (95% CI 0.79–1.88) ml/kg per hour in the FU infusion group (P = 0.01); the median daily sodium excretion was 58 (95% CI 30–366) mEq and 30 (95% CI 10–122) mEq (P = 0.08), respectively The changes in other variables included weight loss [HA+FU 5.2% (95% CI 3.1–8.8); FU 0.8% (95% CI −1.9 to 4.1); P = 0.006]; urine osmolality [HA+FU 315 (95% CI 220–426) mOsm/kg; FU 368 (95% CI 318–446) mOsm/kg; P = 0.13]; osmolal clearance [HA+FU 1600 (95% CI 916–4140) ml/day; FU 880 (95% CI 510–2105) ml/day; P = 0.01; free water clearance [HA+FU −190 (95% CI −960 to 280) ml/day; FU −162 (95% CI −446 to −70) ml/day; P = 0.18]. The findings from this study suggest that the co-administration of albumin and frusemide infusions is more effective than the administration of frusemide infusion alone in inducing diuresis and natriuresis in patients with nephrotic syndrome.     

Maternal characteristics and satisfaction associated with intrapartum epidural analgesia use in Canadian women

BackgroundThe use of epidural analgesia for intrapartum pain relief has increased over recent decades, with rates varying among developed countries. The objective of this study was to determine the socio-demographic and obstetric characteristics and satisfaction associated with epidural analgesia use for intrapartum analgesia in Canadian women.MethodsUsing the Maternity Experiences Survey of the Canadian Perinatal Surveillance System, a randomly-selected sample of 5350 women who had attempted a vaginal birth was examined, representing 63 900 Canadian women. Univariate and multivariate logistic regression models were used to determine the association between socio-demographic and obstetric characteristics and use of epidural analgesia.ResultsThe rate of epidural analgesia use was 57.3% among women with a trial of vaginal birth. Women with higher education levels (OR 1.12, 95%CI 1.07–1.18) and higher income (OR 1.10, 95%CI 1.05–1.14) were more likely to use epidural analgesia. Women were less likely to use epidural analgesia if they were First Nations (OR 0.77, 95%CI 0.69–0.84), unemployed (OR 0.89, 95%CI 0.81–0.97) or a homemaker (OR 0.86, 95%CI 0.82–0.9), living in a rural area (OR 0.60, 95%CI 0.57–0.63), multiparous (OR 0.32, 95%CI 0.31–0.33) and seeing a midwife, family physician or nurse for prenatal (OR 0.6, 95%CI 0.53–0.67, OR 0.71, 95%CI 0.67–0.74, OR 0.75, 95%CI 0.56–0.99, respectively) and intrapartum care (OR 0.12, 95%CI 0.10–0.14, OR 0.58, 95%CI 0.55–0.61, OR 0.58, 95%CI 0.54–0.63, respectively). Maternal prenatal stressors were associated with epidural analgesia use in a non-linear fashion: compared with women with zero stressful events, women with one stressful event were more likely to use epidural analgesia (OR 1.07, 95%CI 1.02–1.12), but women with two or more events were less likely to use epidural analgesia (OR 0.88, 95%CI 0.84–0.92). Satisfaction with labor was high, regardless of type of analgesia used.ConclusionsSocio-demographic and obstetric characteristics, combined with a high satisfaction with labor regardless of the method of pain relief, support the existence of smaller rural obstetric centers unable to provide availability of continuous epidural labor analgesia.     

How to decrease pain at rapid injection of propofol: effectiveness of flurbiprofen

Purpose Many studies have been conducted on how to decrease propofol injection pain, but none has been completely successful. In the present study, the most effective method was investigated by adding lidocaine or a nonsteroidal antiinflammatory drug or by changing the solvent. Methods A total of 250 patients scheduled for general anesthesia were divided into five groups. Anesthesia was induced with intravenous administration of flurbiprofen 50 mg followed immediately by propofol in a long-chain triglyceride (LCT) 2 mg·kg⁻¹ (flurbiprofen group, n = 50), flurbiprofen 50 mg followed by propofol LCT 2 mg·kg⁻¹ 1 min later (flurbiprofen 1 group, n = 50), 2% lidocaine 40 mg followed immediately by propofol LCT 2 mg·kg⁻¹ (lidocaine group, n = 50), propofol LCT 2 mg·kg⁻¹ alone (LCT group, n = 50), or propofol in a mixture of medium-chain triglyceride (MCT) and LCT 2 mg·kg⁻¹ (MCT/LCT group, n = 50). Pain at injection was assessed 10 and 20 s after starting the propofol infusion. Results The numbers of patients with severe and mild pain were larger in the order: LCT group (10 and 31 patients, respectively) > flurbiprofen 1 group (3 and 19) ≥ MCT/LCT group (1 and 14) ≥ lidocaine group (2 and 11) > flurbiprofen group (0 and 0). Conclusions Flurbiprofen 50 mg i.v. just before propofol injection completely abolished propofol injection pain. When it was administered 1 min before propofol injection it was less effective.     

Onset of vecuronium-induced neuromuscular block after a long priming interval

Purpose. We examined whether a new application of the priming principle, i.e., having the priming dose of vecuronium administered before the insertion of the epidural catheter, would hasten the onset of the neuromuscular block induced by the intubating dose of vecuronium. Methods. Forty-five adult female patients scheduled for general anesthesia combined with epidural anesthesia were studied. In group A (n = 15), the priming dose of vecuronium, 0.01 mg·kg⁻¹, was administered before insertion of the epidural catheter. The intubating dose of vecuronium, 0.09 mg·kg⁻¹, was given after the insertion of the epidural catheter. In group B (n = 15), the priming dose of vecuronium, 0.01 mg·kg⁻¹, was given 4 min before the intubating dose of vecuronium, 0.09 mg·kg⁻¹. In the control group (n = 15), no priming dose was given, and only the intubating dose of vecuronium, 0.10 mg·kg⁻¹, was administered. In all three groups, general anesthesia was induced with propofol 2.5 mg·kg⁻¹, and the trachea was intubated when T1/control value (control twitch height in response to train-of-four stimuli) was less than 0.1. Results. In group A, the priming dose was given 16 ± 3 min (mean ± SD) before the administration of the intubating dose. The times to onset of neuromuscular block in groups A and B, and the control group were: 145 ± 30, 184 ± 45, and 219 ± 23 s, respectively (P < 0.05 among the three groups). In all three groups, intubating conditions (graded on a four-point scale) were excellent (P = 0.59). Before the induction of anesthesia, symptoms of paralysis were observed in 5, 4, and 0 patients in groups A and B and the control group, respectively (P < 0.05 between group A or B vs control group). Conclusions. If the priming dose of vecuronium is given after a long priming interval (16 ± 3 min), the time to onset of the neuromuscular block caused by the intubating dose of vecuronium is markedly shorter than when the conventional priming interval of 4 min is employed. Received: March 5, 2001 / Accepted: October 4, 2001     

间断推注与持续背景输注罗哌卡因和阿片类药物用于硬膜外分娩镇痛的Meta分析

目的采用Meta分析评价间断硬膜外推注(intermittent epidural bolus,IEB)(IEB组)与持续硬膜外输注(continuous epidural infusion,CEI)(CEI组)罗哌卡因和阿片类药物用于维持分娩镇痛的有效性和安全性。方法检索CENTRAL、PubMed、EMBASE、WOS、CBM、CNKI、VIP和万方数据库,时间从建库到2018年3月。纳入比较间断1h推注与持续背景输注罗哌卡因和阿片类药物用于维持硬膜外分娩镇痛的随机对照试验(RCT)。采用RevMan 5.3软件进行分析。结果最终纳入文献12篇,共1 383例产妇。与CEI组比较,IEB组明显降低器械助产率(OR=0.52,95%CI 0.33～0.82,P0.05)和运动阻滞发生率(OR=0.15,95%CI 0.05～0.44,P0.05),明显降低麻醉药物额外需求率(OR=0.13,95%CI0.09～0.2,P0.05)和罗哌卡因用量(SMD=-1.04,95%CI-1.18～-0.91,P0.05),明显减少第一产程时间(MD=-11.22min,95%CI-16.51～-5.92,P0.05)和第二产程时间(MD=-3.25min,95%CI-5.14～-1.37,P0.05)。两组剖宫产率、新生儿1min Apgar评分及低血压、恶心呕吐、皮肤瘙痒发生率差异无统计学意义。结论与持续背景输注罗哌卡因和阿片类药物用于维持硬膜外分娩镇痛相比较,间断1h推注的方法可降低器械助产率及运动阻滞发生率,降低麻醉药物的额外需求率同时减少罗哌卡因的用量。     

Awareness and desirability of labor epidural analgesia: a survey of Nigerian women

BackgroundPain relief is an integral part of labor management. Epidural analgesia is the most effective form of pain relief, but in most Nigerian obstetric units it is not available. There is little information on the views of pregnant women about epidural analgesia during labor.MethodsA cross-sectional survey using a structured questionnaire was conducted in the antenatal clinic of University College Hospital, Ibadan, Nigeria to assess women’s views about epidural analgesia.ResultsOf the 650 women surveyed, 523 (80.5%) had knowledge of labour pain while only 127 women (19.5%) were aware of epidural analgesia. Knowledge was affected by parity. Awareness of epidural analgesia was related to occupational status (OR 11.00, 95% CI 5.31-22.83) and having previously experienced childbirth on one previous occasion (OR 1.75, 1.05-2.92). A total of 103 (15.8%) respondents wanted to receive epidural analgesia in their next labor. Occupation (P = 0.006), knowledge of epidural analgesia (P = 0.017) and previous use (P < 0.001) significantly influenced desire for epidural analgesia but only knowledge (OR 2.4 95% CI 1.4-4.3) and previous use (OR 5.3 95% CI 2.1-13.5) were of statistical significance on multivariate analysis.ConclusionThis study shows that the knowledge of labor epidural analgesia amongst Nigerian women is low. Despite limited availability, women who are aware of epidural analgesia and those who have received it in a previous labor were more likely to want it in their forthcoming labor. Some women may refuse its use despite their knowledge.     

Effects of fentanyl on cardiovascular and plasma catecholamine responses in surgical patients

Purpose. Whether opioids administered before skin incision, under inhalational anesthesia, improve cardiovascular and plasma catecholamine responses to surgical stimulation compared with those administered after skin incision remains unclear. We compared the effects of fentanyl injected before and after skin incision on these responses. Methods. We studied 50 healthy female patients [American Society of Anesthesiologist (ASA) physical status 1] who underwent elective total abdominal hysterectomy through an infraumbilical incision (midline incision) under nitrous oxide (60%)–oxygen–isoflurane (1.2%) anesthesia. Fentanyl (2.0 or 4.0 μg·kg⁻¹) was administered IV 5 min before (pretreatment group) or 5 min after (posttreatment group) skin incision. Control patients received a saline injection. Heart rate (HR) and mean arterial blood pressure (MAP) were recorded 1 min before incicsion and serially for 30 min afterward. Plasma levels of norepinephrine (Nor) and epinephrine (Epi) were determined 1 min before incision and serially up to 20 min after skin incision. Results. The MAP response to incision had decreased after 10 min in posttreatment fentanyl (2 μg·kg⁻¹) (P < 0.05) and after 8, 10, 15, and 20 min in posttreatment fentanyl (4 μg·kg⁻¹) (P < 0.05). At the same doses, fentanyl administered before skin incision attenuated MAP response to incision after 1 min with the smaller dose (P < 0.05) and after 1, 3, 5, 6, 8, 10, 15, and 20 min with the higher dose (P < 0.05). Fentanyl suppressed Epi response to surgery 8 and 20 min after skin incision (P < 0.05) at both doses, except for 8 min after incision in pretreatment fentanyl (2 μg·kg⁻¹). Overall, the hemodynamic and sympathoadrenergic responses after skin incision were attenuated, with the exception of plasma Nor after fentanyl irrespective of time and dose. Conclusions. Our results indicated that fentanyl depressed cardiovascular and plasma catecholamine responses irrespective of the time of administration, and that the higher dose of fentanyl produced a greater suppression of MAP and HR responses. In addition, the depressant effects on MAP of high-dose fentanyl administered 5 min before skin incision lasted longer than when injected 5 min after incision. At both doses, the opioid attenuated the rise in plasma Epi, but not Nor. Received: November 9, 2001 / Accepted: March 18, 2002     

Epidural extension failure in obese women is comparable to that of non‐obese women

Background

Management of labor epidurals in obese women is difficult and extension to surgical anesthesia is not always successful. Our previous retrospective pilot study found epidural extension was more likely to fail in obese women. This study used a prospective cohort to compare the failure rate of epidural extension in obese and non‐obese women and to identify risk factors for extension failure.

Methods

One hundred obese participants (Group O, body mass index ≥ 40 kg/m²) were prospectively identified and allocated two sequential controls (Group C, body mass index ≤ 30 kg/m²). All subjects utilized epidural labor analgesia and subsequently required anesthesia for cesarean section. The primary outcome measure was failure of the labor epidural to be used as the primary anesthetic technique. Risk factors for extension failure were identified using Chi‐squared and logistic regression.

Results

The odds ratio (OR) of extension failure was 1.69 in Group O (20% vs. 13%; 95% CI: 0.88–3.21, P = 0.11). Risk factors for failure in obese women included ineffective labor analgesia requiring anesthesiologist intervention, (OR 3.94, 95% CI: 1.16–13.45, P = 0.028) and BMI > 50 kg/m² (OR 3.42, 95% CI: 1.07–10.96, P = 0.038).

Conclusion

The failure rate of epidural extension did not differ significantly between the groups. Further research is needed to determine the influence of body mass index > 50 kg/m² on epidural extension for cesarean section.