A national Israeli survey of neuraxial anesthesia for cesarean delivery: pre-operative block assessment and intra-operative pain management.

BACKGROUND: Neuraxial protocols for cesarean delivery differ among institutions, with various means of assessing the block prior to incision and managing breakthrough intra-operative pain. The different approaches used to deal with these issues in Israel have not been assessed. METHODS: Questionnaires were distributed to all anesthesiologists working in obstetric units in Israeli hospitals. The survey included several non-identifying respondent details intended to allow a description of the study population as a whole and multiple-choice questions addressing neuraxial techniques, method of pre-operative block assessment and medications used to treat intra-operative pain. RESULTS: Three hundred and sixty-one doctors completed the survey in 24 medical centers, an 81.1% response rate. Thirteen different protocols for spinal anesthesia and 20 different protocols for epidural anesthesia were described. Nine different protocols for assessment of the block prior to incision were identified, with significant inter-institutional differences (P <0.001). For treatment of intra-operative pain prior to delivery, 35.7% of spinals given and 40% of epidurals given were converted to general anesthesia whereas, after delivery, conversion of spinal to general anesthesia was 18% and epidural to general anesthesia was 18.6%. CONCLUSIONS: There were a variety of spinal and epidural regimens used as well as different methods for assessing the block and managing intra-operative pain. Further studies should be performed to identify optimal techniques for neuraxial anesthesia for pre-operative block assessment and for management of intra-operative pain.

Use of high-resolution thermography as a validation measure to confirm epidural anesthesia in mice: a cross-over study.

BACKGROUND: Effective epidural anesthesia is confirmed in humans by sensory assessments but these tests are not feasible in mice. We hypothesized that, in mice, infrared thermography would demonstrate selective segmental warming of lower extremities following epidural anesthesia. METHODS: We anesthetized 10 C57BL/6 mice with isoflurane and then inserted a PU-10 epidural catheter under direct surgical microscopy at T11-12. A thermal camera (thermal sensitivity ±0.05°C, pixel resolution 320x240 pixels, and spatial resolution 200 µm) recorded baseline temperature of front and rear paws, tail and ears. Thermography was assessed at baseline and 2, 5, 10, and 15 min after an epidural bolus dose of 50 µL bupivacaine 0.25% or 50 µL saline (control) using a cross-over design with dose order randomized and investigators blinded to study drug. Thermal images were recorded from video and analyzed using FLIR software. Effect over time and maximal effect (Emax) were assessed by repeated measures ANOVA and paired t-tests. Comparisons were between bupivacaine and control, and between lower vs upper extremities. RESULTS: Epidural bupivacaine caused progressive warming of lower compared with upper extremities (P <0.001), typically returning to baseline by 15 min after administration. Mean (±SD) Emax was +3.73 (±1.56) °C for lower extremities compared with 0.56 (±0.68) °C (P=0.03) for upper extremities. Following epidural saline, there was no effect over time (Emax for lower extremities -0.88 (±0.28) °C compared with the upper extremities -0.88 (±0.19) °C (P >0.99). CONCLUSIONS: Thermography is a useful tool to confirm epidural catheter placement in animals for which subjective, non-noxious, sensory measures are impossible.

Choice of local anaesthetic for epidural caesarean section: a Bayesian network meta-analysis.

Rapid-onset epidural local anaesthesia can avoid general anaesthesia for caesarean delivery. We performed a Bayesian network meta-analysis of direct and indirect comparisons to rank speed of onset of the six local anaesthetics most often used epidurally for surgical anaesthesia for caesarean delivery. We searched Google Scholar, PubMed, EMBASE, Ovid, CINAHL and CENTRAL to June 2019. We analysed 24 randomised controlled trials with 1280 women. The mean (95%CrI) onset after bupivacaine 0.5% was 19.8 (17.3-22.4) min, compared with which the mean (95%CrI) speed of onset after lidocaine 2% with bicarbonate, 2-chloroprocaine 3% and lidocaine 2% was 6.4 (3.3-9.6) min faster, 5.7 (3.0-8.3) min faster and 3.9 (1.8-6.0) min faster, respectively. Speed of onset was similar to bupivacaine 0.5% after ropivacaine 0.75% and l-bupivacaine 0.5%: 1.6 (-1.4 to 4.8) min faster and 0.4 (-2.2 to 3.0) min faster, respectively. The rate (95%CrI) of intra-operative hypotension was least after l-bupivacaine 0.5%, 315 (236-407) per 1000, and highest after 2-chloroprocaine 3%, 516 (438-594) per 1000. The rate (CrI) of intra-operative supplementation of analgesia was least after ropivacaine 0.75% 48 (19-118) per 1000 and highest after 2-chloroprocaine 3%, 250 (112-569) per 1000.

A 10-year update: national survey questionnaire of obstetric anesthesia units in Israel.

BACKGROUND: This nationwide survey was conducted to provide data about the obstetric anesthesia services in Israeli labor and delivery units in 2016. METHODS: Prospective survey questionnaire was emailed to obstetric anesthesia unit directors/chairperson of all 25 labor and delivery services units within the jurisdiction of the Israeli Ministry of Health. RESULTS: The response rate was 100%. Nineteen (76%) units have dedicated anesthesiologist cover. Fifteen (60%) units offered nitrous oxide, four units (16%) offered patient-controlled intravenous fentanyl and six units (24%) offered patient-controlled intravenous remifentanil for alternative labor analgesia. The median (range) epidural rate was 60% (22-85%). The median (range) cesarean delivery rate was 20% (10-26%). Overall, general anesthesia was performed for median (range) 10% (1-25%) of cesarean deliveries. Neuraxial anesthesia was performed for 95% (40-99%) of elective and 60% (0-90%) of urgent cesarean deliveries. Intrathecal morphine was administered routinely for spinal anesthesia for post-cesarean delivery analgesia in 11 (44%) units. Nineteen (72%) units had a written aspiration prophylaxis protocol; 20 (80%) had a written labor analgesia protocol; 19 (76%) had a postdural puncture headache management protocol; 20 (80%) had a local anesthetic toxicity protocol; 24 units had Intralipid available in the unit. CONCLUSION: No new labor units have opened since 2005, despite huge increases in delivery volume in many units. These units manage increased numbers of epidurals and cesarean deliveries. Use of intrathecal morphine for spinal anesthesia has become more widespread. Future efforts should focus on availability of emergency equipment, separate obstetric anesthesia staffing, and establishing emergency protocols.

Choice of anaesthesia for category-1 caesarean section in women with anticipated difficult tracheal intubation: the use of decision analysis.

A predicted difficult airway is sometimes considered a contra-indication to rapid sequence induction of general anaesthesia, even in an urgent case such as a category-1 caesarean section for fetal distress. However, formally assessing the risk is difficult because of the rarity and urgency of such cases. We have used decision analysis to quantify the time taken to establish anaesthesia, and probability of failure, of three possible anaesthetic methods, based on a systematic review of the literature. We considered rapid sequence induction of general anaesthesia with videolaryngoscopy, awake fibreoptic intubation and rapid spinal anaesthesia. Our results show a shorter mean (95% CI) time to induction of 100 (87-114) s using rapid sequence induction compared with 9 (7-11) min for awake fibreoptic intubation (p < 0.0001) and 6.3 (5.4-7.2) min for spinal anaesthesia (p < 0.0001). We calculate the risk of ultimate failed airway control after rapid sequence induction to be 21 (0-53) per 100,000 cases, and postulate that some mothers may accept such a risk in order to reduce potential fetal harm from an extended time interval until delivery. Although rapid sequence induction may not be the anaesthetic technique of choice for all cases in the circumstance of a category-1 caesarean section for fetal distress with a predicted difficult airway, we suggest that it is an acceptable option.

Pre-delivery remifentanil infusion for placenta accreta cesarean delivery under general anesthesia: an observational study.

OBJECTIVE: General anesthesia may be required for placenta accreta cesarean delivery. Intrauterine fetal anesthetic exposure should be minimized to avoid neonatal respiratory depression; opioids are often delayed until post-delivery. METHODS: In this observational study, we compared neonatal outcome using pre-delivery remifentanil versus post-delivery (deferred) opioids for placenta accreta cesarean delivery. Choice of anesthesia was discretionary. The primary outcome was Apgar score at 5 min comparing women who received pre-delivery remifentanil versus deferred opioid administration. We recorded maternal/obstetric characteristics, surgical characteristics, maternal hemodynamic data, neonatal outcomes: Apgar scores, umbilical vein pH and respiratory interventions at birth. RESULTS: Between February 2007 and April 2014 we identified 40 general anesthesia placenta accreta cesarean deliveries. The remifentanil dose rate ranged from 0.06 to 0.46 mcg kg(-1 )min(-1). Obstetric and maternal characteristics were similar. Neonatal Apgar, umbilical pH and respiratory intervention outcomes were similar in both groups; Apgar scores median (interquartile range IQR [range]) at 5 min were 9 (8-10) for pre-delivery remifentanil versus 9 (9-10) for deferred opioid administration, p = 0.18. CONCLUSIONS: We did not observe a significant effect on neonatal Apgar scores at 1 and 5 min, or respiratory interventions at birth when remifentanil infusion was administered pre-delivery.

Israeli survey of anesthesia practice related to placenta previa and accreta.

BACKGROUND: Anesthesia practices for placenta previa (PP) and accreta (PA) impact hemorrhage management and other supportive strategies. We conducted a survey to assess reported management of PP and PA in all Israeli labor and delivery units. METHODS: After Institutional Review Board waiver, we surveyed all 26 Israeli hospitals with a labor and delivery unit by directly contacting the representatives of obstetric anesthesiology services in every department (unit director or department chair). Each director surveyed provided information about the anesthetic and transfusion management in their labor and delivery units for three types of abnormal placentation based on antenatal placental imaging: PP, low suspicion for PA, and high suspicion for PA. The primary outcome was use of neuraxial or general anesthesia for PP and PA Cesarean delivery. Univariate statistics were used for survey responses using counts and percentages. RESULTS: The response rate was 100%. Spinal anesthesia is the preferred anesthetic mode for PP cases, used in 17/26 (65.4%) of labor and delivery units. By comparison, most representatives reported that they perform general anesthesia for patients with PA: 18/26 (69.2%) for all low suspicion cases of PA and 25/26 (96.2%) for all high suspicion cases of PA. Although a massive transfusion protocol was available in the majority of hospitals (84.6%), the availability of thromboelastography and cell salvage was much lower (53.8% and 19.2% hospitals respectively). CONCLUSIONS: In our survey, representatives of anesthesia labor and delivery services in Israel are almost exclusively using general anesthesia for women with high suspicion for PA; however, almost two-thirds use spinal anesthesia for PP without suspicion of PA. Among representatives, we found wide variations in anesthesia practice patterns with regard to anesthesia mode, multidisciplinary management, and hemorrhage anticipation strategies.

Peripartum anesthetic management of renal transplant patients--a multicenter cohort study.

As the number and success of renal transplantation has grown, there has been an increase in the number of renal transplant patients giving birth. To date, there has been no data on obstetric anesthesia management of these patients. The purpose of this study was to build an Israeli national database on parturients after renal transplant. A sixteen-year (calendar years 1996-2011) retrospective study was conducted at three major tertiary centers with a combined current birth rate of approximately 25,000 deliveries annually. We found 83 labors in 64 women. Forty-two percent of this population suffered from hypertension while 12.5% had diabetes. Forty-seven percent of women had a vaginal delivery while 53% of women had a cesarean section. The rate of epidural analgesia for labor was 59%, and rate of regional anesthesia during cesarean section was 75%. There were no anesthetic complications in any cases. Standard ASA monitoring was used in all cases except for one woman with severe hypertension who required an arterial line during her cesarean section. Forty-seven percent of newborn were under 37 weeks with average gestational week 36 ± 3 days and birth weight 2.5 ± 0.7 kg. Average Apgar was 8.4 ± 1.3 at one minute and 9.3 ± 0.7 at five minutes. There was one neonatal death in the CS group due to placental abruption. Patients after renal transplant can safely undergo birth and obstetric analgesia.

Outcomes of prospectively-collected consecutive cases of antenatal-suspected placenta accreta.

BACKGROUND: Accurate diagnosis of placenta accreta is tentative before surgery. This study developed a predictive score for antenatal diagnosis of placenta accreta through mathematical modeling using clinical signs. METHODS: Antenatal cases of suspected placenta accreta were collected prospectively in a single-site tertiary delivery center. Women with clinical signs of placenta accreta (placenta previa, number of previous cesarean deliveries and/or ultrasound suspicion of placenta accreta) were included. The diagnosis of accreta was confirmed surgically. The primary endpoint was the proportion of surgically-diagnosed placenta accreta among all suspected cases. Logistic regression modeling was performed to assess preoperative risk factors for placenta accreta. The risk score was tested on a receiver operator characteristic curve to identify subjects with placenta accreta and the optimum cut-point was chosen. RESULTS: Over nine years, 92 suspected accreta cases were identified from 46623 deliveries (0.2%). The diagnosis was confirmed at surgery in 52/92 cases (56%) and there were no maternal deaths. Blood transfusion requirements were greater in patients with placenta accreta versus patients without placenta accreta (median 7 [range 0-25, interquartile range 3-10] versus 0 [0-6, 0-2] units of blood, P <0.0001). Area under the curve of the receiver operator characteristic curve was 0.846, with contribution from three variables (placenta previa, number of previous cesarean deliveries and ultrasound suspicion), each with a P value <0.05. From the ROC curve a cut-point with 100% sensitivity and specificity 25% (95% CI 12.69%-41.20%) was achieved, compared with 86.6% sensitivity (95% CI 74.21%-94.41%) and 60.0% specificity (95% CI 43.33%-75.14%) using ultrasound alone. CONCLUSIONS: Combining diagnostic features associated with placenta accreta through mathematical modeling has better positive predictive value than ultrasound alone.

Duration of analgesia and pruritus following intrathecal fentanyl for labour analgesia: no significant effect of A118G µ-opioid receptor polymorphism, but a marked effect of ethnically distinct hospital populations.

BACKGROUND: Genetic polymorphism (A118G) in the µ-opioid receptor has been reported to affect systemic opioid analgesia. However, reported pharmacogenetic effects on spinal opioid analgesia, particularly in labour, have been equivocal. METHODS: We prospectively assessed effects of the µ-opioid receptor A118G single nucleotide polymorphism (SNP) on analgesia after 20 µg of spinal fentanyl. We studied two ethnically distinct hospital populations (Miami and Jerusalem). Independent variables were A118G, ethnicity, and hospital. Primary outcome was time from spinal analgesia until analgesic request. Secondary outcomes were pain and pruritus, assessed at repeated intervals until analgesia request. RESULTS: One hundred and twenty-five nulliparous parturients in early labour were analysed. The allelic frequency of A118G was 14.8% (14.4% in Miami; 15.5% in Jerusalem). Time to analgesia request (sd) in Miami was 122 (44) min and in Jerusalem was 87 (32) min, P<0.001; Hispanic 123 (46) min vs Jew/Arab 87 (32) min, P<0.001; Black 121 (41) min vs Jew/Arab 87 (32) min, P=0.015. There was no significant effect of A118G. Survival analysis showed Miami > Jerusalem, P<0.001; Hispanics and Black > Jew/Arab, P<0.001; no effect of A118G. Within hospital groups, A118G had no effect on time to analgesic request; within genomic groups there was a significant difference between hospitals. The time-course for pruritus exactly paralleled the time-course for analgesia and was affected by hospital (P=0.006) and by ethnic group (P=0.03), but not by A118G. CONCLUSIONS: We found no significant effect for the A118G single nucleotide polymorphism (SNP) on analgesic duration after spinal fentanyl for labour. In contrast, ethnically distinct hospital population groups exerted a marked effect on the time-course of both analgesia and pruritus.

Analgesic and sympatholytic effects of low-dose intrathecal clonidine compared with bupivacaine: a dose-response study in female volunteers.

BACKGROUND: A wide range of doses has been suggested for intrathecal clonidine, but no dose-ranging study has examined analgesic effects below 100 µg. The primary aim of this volunteer study was to assess the dose vs analgesic effect relationship for doses of intrathecal clonidine below 100 µg. METHODS: After IRB approval and signed informed consent, 11 healthy female volunteers participated in this randomized, double-blinded, cross-over study using a dose-ranging sparse-sampling technique. Participants received intrathecal clonidine (doses 0-100 µg; n=10) and intrathecal bupivacaine (doses 0-8.8 mg; n=9) on separate study days. At baseline, 30, and 60 min from drug administration, experimental heat pain tolerance was assessed at both a lumbar and a cranial dermatome. Heat and cold perception thresholds were assessed at the same time intervals. Heart rate (HR), arterial pressure, and forearm-finger and toe-leg cutaneous temperature gradients (Tfinger-arm and Ttoe-leg) were used as measures of sympatholysis. RESULTS: Both intrathecal clonidine and bupivacaine caused significant, dose-dependent analgesic effects at the leg but not the head. Significant analgesia to experimental heat pain was detected above 25 µg clonidine and 3 mg bupivacaine. Administration of bupivacaine but not clonidine resulted in a significant dose-related decrease in HR and Ttoe-leg; neither drug caused dose-related sympatholytic effects in the doses used. CONCLUSIONS: After 50 µg clonidine or 5 mg bupivacaine, the heat pain tolerance increased by ∼1°C, similar to the analgesic effect of 5 mg epidural morphine or 30 µg epidural fentanyl in previous studies using this experimental heat pain model. Our results provide additional data for rational dose selection of intrathecal clonidine.

Influence of preoperative anxiety on hypotension after spinal anaesthesia in women undergoing Caesarean delivery.

BACKGROUND: We designed a prospective observational study to assess the effect of preoperative anxiety on hypotension after spinal anaesthesia. METHODS: After IRB approval and signed informed consent, 100 healthy term parturients undergoing elective Caesarean delivery under spinal anaesthesia were enrolled. Direct psychological assessments of preoperative anxiety were verbal analogue scale (VAS) (0-10) anxiety score and State-Trait Anxiety Inventory questionnaire (STAI-s); salivary amylase was measured as an indirect physical assessment of anxiety. Direct and indirect anxiety data were transformed into ordinal groups for low, medium, and high anxiety (VAS: low 0-3, medium 4-6, high 7-10; STAI-s: low <40, medium 40-55, high >55; log(10) salivary amylase: low <3, medium 3-4, high >4). Spinal anaesthesia was performed using hyperbaric bupivacaine 10 mg and fentanyl 20 µg. All patients received i.v. crystalloid 500 ml prehydration and 500 ml cohydration. Hypotension was treated by standardized protocol (fluid bolus and ephedrine or phenylephrine depending on maternal heart rate). Systolic arterial pressure (SAP) was measured at baseline and every minute after spinal anaesthesia. The effect of low, medium, and high anxiety groups on the maximum percentage change in SAP (%ΔSAP) was assessed (one-way analysis of variance, Tukey's honestly significant difference). RESULTS: Ninety-three patients were included in analysis. There was a significant effect of direct psychological measures of anxiety on %ΔSAP (VAS P=0.004; STAI-s P=0.048). There was a significant difference between low and high anxiety groups (VAS P=0.003; STAI-s P=0.038), but not between other anxiety groups. Salivary amylase did not correlate with %ΔSAP. CONCLUSIONS: Preoperative anxiety assessed by VAS had a significant effect on hypotension after spinal anaesthesia.

Novel pulsatile cerebrospinal fluid model to assess pressure manometry and fluid sampling through spinal needles of different gauge: support for the use of a 22 G spinal needle with a tapered 27 G pencil-point tip.

BACKGROUND: Parallel-walled spinal needles ≤ 22 G are routinely used for lumbar puncture, despite a reported ≥ 32% incidence of post-dural puncture headache. A tapered spinal needle (22 G shaft, 27 G tip) is in use in our institution. We hypothesized that despite the smaller dural puncture hole, this needle has similar cerebrospinal fluid (CSF) pressure equilibration times and CSF sampling times to a standard 22 G needle and assessed a range of spinal needles using an experimental pulsatile CSF reservoir. METHODS: The pulsatile CSF reservoir had an oscillating pressure varying between 25 and 15 cm H(2)O at a cycle frequency of 80 s(-1). We tested seven parallel-walled spinal needles (18-27 G) and the tapered 22/27 G needle. CSF pressure was measured every 2 s by manometry. The time to collect 1 ml CSF samples was measured. Saline 0.9% and mannitol 20% were tested separately. One-way ANOVA with Bonferroni post-hoc test was used to compare 22G, 27G and 22/27G needles. RESULTS: The mean [standard deviation (sd)] CSF pressure equilibration time (saline) was 40.7 (6.4), 108.7 (6.1), and 51.3 (4.6) s for the 22, 27, and 22/27 G needles (P< 0.0001 for comparisons between 27 G and other needles). The mean (sd) CSF sampling time (saline) was 40.3 (3.1), 225.3 (10.0), and 63.0 (5.2) s for the 22, 27, and 22/27 G needles (P< 0.0001 for comparisons between 27 G and other needles, and P= 0.019 between 22 and 22/27 G needles). Saline was different from mannitol for both measurements and all needles (P< 0.0001). CONCLUSIONS: A 22/27 G tapered spinal needle has similar flow properties to the 22 G needle, despite a 27 G tip.

Intrathecal fentanyl added to bupivacaine and morphine for cesarean delivery may induce a subtle acute opioid tolerance.

BACKGROUND: Previous studies have demonstrated that the addition of intrathecal fentanyl to a spinal anesthetic for cesarean delivery improves intraoperative analgesia. However, intrathecal fentanyl may induce acute tolerance to opioids. The objective of this study was to investigate whether the addition of intrathecal fentanyl to spinal anesthesia with intrathecal morphine increases postoperative analgesic requirements and pain scores. METHODS: In this randomized, double-blinded study, 40 women having elective cesarean delivery were enrolled. Patients received spinal anesthesia with hyperbaric bupivacaine 12 mg, morphine 200 µg, and fentanyl 0, 5, 10 or 25 µg. Each patient received intravenous patient-controlled analgesia morphine for 24h postoperatively. Outcome measures included postoperative morphine usage and pain scores, as well as intraoperative pain, nausea, hypotension and vasopressor use. RESULTS: Total morphine use over the 24-h post-spinal study period was similar among the study groups (P=0.129). Postoperative pain scores were higher in patients receiving fentanyl 5, 10 and 25 µg compared to fentanyl 0 µg control group (P=0.003). CONCLUSIONS: The study results suggest that intrathecal fentanyl may induce acute tolerance to intrathecal morphine. However, because there was no difference in postoperative analgesia requirement and the difference in pain scores was small, the clinical significance of this finding is uncertain.

Obstetric anesthesia units in Israel: a national questionnaire-based survey.

BACKGROUND: This survey was performed to assess the organization and practice of obstetric anesthesia units in Israel. METHODS: A written questionnaire was mailed at the end of December 2005 to all Israeli anesthesia departments providing labor and delivery services in 2005 (n=25). RESULTS: A response rate of 100% accounted for 125,340 deliveries. All labor and delivery suites had on-site anesthesia department services. Data are presented as mean (range) or frequency. Eleven hospitals performed 2500-4999 deliveries/year, 6 hospitals 5000-7499 deliveries/year, and 4 hospitals 7500-9999 deliveries/year. The overall cesarean delivery rate was 20% (0-27). Anesthesia for cesarean delivery (elective and emergency combined) was provided by: general anesthesia 15% (0.5-50), epidural 14.5% (0-99.5), spinal 68% (0-98), or combined spinal-epidural technique 0% (0-30). There was an operating room within or immediately adjacent to the labor ward in 16/25 units, including 10/11 units with >5000 deliveries/year. Labor analgesia was provided by epidural techniques in 50% (4-93) and nitrous oxide in 0.5% (0-90) of deliveries. A total of 11 units had 24h dedicated anesthesiologist coverage, including all units >7500 deliveries but only 3/8 (38%) with 5000-7500 deliveries. Two of the 4 units with >7500 deliveries had no faculty member with formal training in obstetric anesthesia. Written protocols were available for labor analgesia (17/25), post-partum hemorrhage (12/25), aspiration prophylaxis (15/25) and maternal resuscitation (8/25). CONCLUSION: In this national appraisal of Israeli obstetric anesthesia services, a notable lack of written protocols, wide variations in staffing, and few specifically trained obstetric anesthesia personnel were observed.