Utility of ultrasonography in identification of midline and epidural placement in severely obese parturients.

BACKGROUND: Due to body habitus, lumbar epidural placement can be challenging in severely obese parturients. Several studies have been published assessing the usefulness of ultrasonography in the placement of neuraxial blocks. One patient population that is under-represented in these studies is the severely obese parturient. We sought to determine if performing an abbreviated ultrasound exam of the lumbar spine to determine midline by locating spinous process could facilitate lumbar epidural placement in severely obese parturients. METHODS: One hundred fifty patients with a Body Mass Index (BMI) of ≥35 kg/m2 were randomized into two groups. The palpation (P) group had midline identified by the traditional palpation technique. The ultrasonography (U) group had midline identified by ultrasound visualization of the spinous process in the transverse plane. Midline identification and epidural placement were done by both junior and senior anesthesiology residents at our teaching institution. RESULTS: Data were analyzed on all 150 patients. BMI was similar in the U and P groups (43.3 vs. 44.4 kg/m2, P=0.359). Time for epidural placement (6.2 vs. 9.0 minutes, P<0.01) and total procedure time (6.9 vs. 9.5 minutes, P<0.01) were significantly less in the U group. The number of needle passes (2.1 vs. 2.8, P=0.02) was also less in the U group. There was no significant difference in the failure rates of the U and P groups (4.0% vs. 9.3%, P=0.19). CONCLUSIONS: The use of an abbreviated ultrasound exam to identify midline in severely obese parturients can reduce the time required for lumbar epidural placement.

Comparing low-dose bupivacaine with epidural volume extension to standard bupivacaine dosing for short obstetric procedures: a prospective, randomized study.

BACKGROUND: Intrathecal bupivacaine's long duration of action can unnecessarily increase the time to meet Postanesthesia Care Unit (PACU) discharge criteria for patients undergoing short obstetric procedures. We sought to use a technique known as epidural volume extension (EVE) to determine if we could provide an adequate surgical block while significantly decreasing the time required to meet PACU discharge criteria for patients undergoing short obstetric procedures. METHODS: Fifty participants were randomized into two groups. The control group received a 10 mg of 0.5% isobaric bupivacaine plus 15 µg of fentanyl injection in the intrathecal space via a combined spinal-epidural technique. The EVE group received a 5 mg of 0.5% isobaric bupivacaine plus 15 µg of fentanyl injection in the intrathecal space followed immediately by a 10 mL injection of sterile saline through the epidural needle for the EVE. RESULTS: Data were analyzed on 45 of the 50 patients. Time to meet PACU discharge criteria was significantly reduced in the EVE group when compared to the control group (50 vs. 135 minutes, P<0.001). The EVE group had a faster time to complete motor recovery when compared to the control group (66 vs. 181 minutes, P<0.001). Peak block height was similar in both groups at the time of surgery start (T5 vs. T5, P=0.44). CONCLUSIONS: The use of low-dose isobaric bupivacaine in combination with 10 mL of saline EVE allows for faster motor recovery and time to meet PACU discharge criteria in patients undergoing short obstetric procedures.

Obesity and Neonatal Cord Blood Gas Results at Cesarean: Effect of Intraoperative Blood Pressure.

Objective Our aims were to evaluate whether there is an inverse association between body mass index (BMI) and umbilical artery pH and to investigate the contribution of intraoperative hypotension on the umbilical artery pH. Study Design We conducted a retrospective cohort study of all women with a nonanomalous singleton at 37 to 41 weeks who underwent a scheduled cesarean delivery under spinal anesthesia at our facility from January 2006 to March 2012. The primary outcome was the proportion of patients in each BMI category with arterial cord pH < 7.10. Intraoperative blood pressure data were compared across BMI categories. Results In total, 717 mother-infant pairs met enrollment criteria. Mean arterial pH was significantly lower in women with elevated BMI (p = 0.014), notably with BMI ≥ 40 kg/m2. Baseline blood pressure increased linearly with increasing BMI (p < 0.001), however, so did the maximum drop in all blood pressure parameters (p < 0.001). After adjusting for potential confounders, including blood pressure, there was no longer an association between cord pH and BMI (p = 0.72). Conclusion For women undergoing a scheduled cesarean delivery under spinal anesthesia, umbilical artery pH is lower in women with BMI ≥40 kg/m2. Relative hypotension after spinal anesthesia is more pronounced with increasing BMI and may explain this effect.

Epidural use and clinical chorioamnionitis among women who delivered vaginally.

OBJECTIVE: Chorioamnionitis, an important cause of maternal and neonatal morbidity, is influenced by epidural use and the occurrence of epidural fever. We evaluated the association between chorioamnionitis, histologic placental findings, and intrapartum factors focusing on epidural use. MATERIALS AND METHODS: We conducted a secondary analysis of a randomized controlled trial of different doses of oxytocin to prevent postpartum hemorrhage among women who delivered vaginally. The primary outcome was clinical diagnosis of chorioamnionitis leading to antibiotic therapy. Intrapartum factors examined included epidural use, parity, labor induction, gestational age, maternal age, ethnicity, body mass index, cervical dilatation at admission, preeclampsia/eclampsia, preterm labor, and duration of labor. RESULTS: Of the 1,798 women randomized, we excluded 13 multifetal births leaving 1,785 for analysis: 1,491 had an epidural and 294 did not. Of those with epidural, 8.0% had clinically diagnosed chorioamnionitis compared with only 1.0% without epidural: unadjusted odds ratio (OR) = 8.3 (95% confidence interval [CI]: 2.63-26.40); p < 0.0001. After multivariable logistic regression, epidural use (adjusted OR: 5.80; 95% CI: 1.77-19.11), increasing parity (0.42; 0.32-0.55), and preeclampsia (0.31; 0.14-0.66) were significantly associated with chorioamnionitis. CONCLUSION: Epidural use is statistically associated with an increase in clinical diagnosis of chorioamnionitis. A cause and effect relationship cannot be confirmed from this study. Independently of labor duration and increasing parity, preeclampsia appeared protective.

Preoperative screening and case cancellation in cocaine-abusing veterans scheduled for elective surgery.

Background. Perioperative management of cocaine-abusing patients scheduled for elective surgery varies widely based on individual anecdotes and personal experience. Methods. Chiefs of the anesthesia departments in the Veterans Affairs (VA) health system were surveyed to estimate how often they encounter surgical patients with cocaine use. Respondents were asked about their screening criteria, timing of screening, action resulting from positive screening, and if they have a formal policy for management of these patients. Interest in the development of VA guidelines for the perioperative management of patients with a history of cocaine use was also queried. Results. 172 VA anesthesia departments' chiefs were surveyed. Response rate was 62%. Over half of the facilities see cocaine-abusing patients at least once a week (52%). Two thirds of respondents canceled or delayed patients with a positive screen regardless of clinical symptoms. Only eleven facilities (10.6%) have a formal policy. The majority of facilities (80%) thought that having formal guidelines for perioperative management of cocaine-abusing patients would be helpful to some extent. Results. 172 VA anesthesia departments' chiefs were surveyed. Response rate was 62%. Over half of the facilities see cocaine-abusing patients at least once a week (52%). Two thirds of respondents canceled or delayed patients with a positive screen regardless of clinical symptoms. Only eleven facilities (10.6%) have a formal policy. The majority of facilities (80%) thought that having formal guidelines for perioperative management of cocaine-abusing patients would be helpful to some extent. Conclusions. There is a general consensus that formal guidelines would be helpful. Further studies are needed to help formulate evidence-based guidelines for managing patients screening positive for cocaine prior to elective surgery.

Airway management and vascular access simulation during a medical student rotation.

BACKGROUND: Medical students electing to spend a month in anaesthesiology during their third or fourth year often experience airway management and vascular access for the first time on an actual patient. An airway management and vascular access simulation course for medical students was developed and implemented at our institution. The purpose of this study was to assess the subjective comfort level after implementing this teaching tool in medical students. METHODS: A brief didactic course on airway management and vascular access was provided to medical students on the first day of their anaesthesiology rotation. A survey was presented to the students immediately after a focused 1-hour lecture and prior to a simulation session. The pre-simulation survey was comprised of eight questions asking the medical students to rate their level of comfort with both types of procedures. The lecture was followed by a 1-hour simulation course on manikins. The medical students were asked to complete a post-simulation survey, which was comprised of the same initial eight questions. RESULTS: After participating in the didactic course and manikin simulation, the self-perceived comfort level of medical students with airway management (p < 0.0005), vascular access (p < 0.0005) and interpretation of the vascular pressure waveforms (p < 0.0005) demonstrated significant improvement. DISCUSSION: The results of this study suggest that providing medical students with a brief didactic session on airway and vascular access, including simulation on manikins, prior to the start of their encounter with actual surgical patients, can improve their comfort level in performing both procedures.

Anesthesia for laparoscopic donor nephrectomy: is nitrous oxide contraindicated?

PURPOSE: We performed this study to test the hypothesis that nitrous oxide produces clinically significant bowel distention during laparoscopic abdominal surgery. MATERIALS AND METHODS: Laparoscopic kidney donors were randomized into 2 groups. Group 1 received N2O and oxygen inhalation through anesthesia, and group 2 received a mixture of air and oxygen. All patients received the same preanesthetic and anesthetic medications. The surgeon was blinded to the use of N2O. The surgeon was given the option to discontinue N2O use (if it was used) if he/she thought that the bowel distention was increasing surgical risk. Postoperative data were collected on bowel symptoms, pain and recovery. RESULTS: A total of 28 patients were enrolled in the study, 12 of whom received N2O (group 1) and 16 who did not receive N2O (group 2). Mild to moderate bowel distention was reported by the surgeons in 6 patients (50%) in group 1 and 1 patient only in group 2 (6%, p=0.007). Severe bowel distention was encountered in 4 patients, 3 of whom received N2O (25% of group 1). Nausea and vomiting on postoperative day 1 was reported by 50% of patients in group 1 and 25% of group 2. There was no difference in the pain scores between the 2 groups. No intraoperative or postoperative complications were encountered. CONCLUSIONS: The use of N2O anesthetic causes bowel distention in 50% of abdominal laparoscopic donor nephrectomy operations. The distention was severe enough to interfere with the progress of surgery in 25% of cases and the use of N2O had to be discontinued.