The Society for Obstetric Anesthesia and Perinatology Interdisciplinary Consensus Statement on Neuraxial Procedures in Obstetric Patients With Thrombocytopenia.

Because up to 12% of obstetric patients meet criteria for the diagnosis of thrombocytopenia in pregnancy, it is not infrequent that the anesthesiologist must decide whether to proceed with a neuraxial procedure in an affected patient. Given the potential morbidity associated with general anesthesia for cesarean delivery, thoughtful consideration of which patients with thrombocytopenia are likely to have an increased risk of spinal epidural hematoma with neuraxial procedures, and when these risks outweigh the relative benefits is important to consider and to inform shared decision making with patients. Because there are substantial risks associated with withholding a neuraxial analgesic/anesthetic procedure in obstetric patients, every effort should be made to perform a bleeding history assessment and determine the thrombocytopenia etiology before admission for delivery. Whereas multiple other professional societies (obstetric, interventional pain, and hematologic) have published guidelines addressing platelet thresholds for safe neuraxial procedures, the US anesthesia professional societies have been silent on this topic. Despite a paucity of high-quality data, there are now meta-analyses that provide better estimations of risks. An interdisciplinary taskforce was convened to unite the relevant professional societies, synthesize the data, and provide a practical decision algorithm to help inform risk-benefit discussions and shared decision making with patients. Through a systematic review and modified Delphi process, the taskforce concluded that the best available evidence indicates the risk of spinal epidural hematoma associated with a platelet count ≥70,000 × 106/L is likely to be very low in obstetric patients with thrombocytopenia secondary to gestational thrombocytopenia, immune thrombocytopenia (ITP), and hypertensive disorders of pregnancy in the absence of other risk factors. Ultimately, the decision of whether to proceed with a neuraxial procedure in an obstetric patient with thrombocytopenia occurs within a clinical context. Potentially relevant factors include, but are not limited to, patient comorbidities, obstetric risk factors, airway examination, available airway equipment, risk of general anesthesia, and patient preference.

Nerve stimulator-guided supplemental popliteal sciatic nerve block after a failed sciatic block does not increase the incidence of transient postoperative neurologic sequelae.

BACKGROUND: Supplemental peripheral nerve blocks are not commonly performed in adults because of concerns of cumulative exposure of the nerve to the local anesthetic as well as increased ischemia from epinephrine. The purpose of this study was to compare the incidence of postoperative neurologic symptoms after a failed subgluteal sciatic nerve block and a supplemental popliteal sciatic nerve block. METHODS: Five hundred twelve adult patients undergoing ambulatory surgery were prospectively studied (1 yr). Sciatic nerve blocks were performed using levobupivacaine 0.625% with epinephrine 1:200,000 (0.5 ml/kg). Patients who failed to achieve sensory and motor anesthesia at 30-60 min were given a popliteal sciatic nerve block (lidocaine 2% 10 ml + levobupivacaine 0.5% 10 ml). Subjects were contacted at 24 h to 48 h, 2 weeks, and 1 month. Symptomatic patients were contacted biweekly and reevaluated during follow-up surgeon visits until symptom resolution. RESULTS: Four hundred thirty-nine subjects were analyzed. Fifty-six received a popliteal sciatic nerve block. Four subjects (0.9%) had self-reported neurologic symptoms in the distribution of the sciatic nerve. Investigator-initiated follow-up revealed 33 subjects (8.7%) who received a single subgluteal sciatic block and 4 subjects (7.1%) after a supplemental sciatic nerve block with neurologic symptoms (P = 0.80). The median duration of symptoms was 4 weeks (95% CI 3-5) in the subgluteal and 4 weeks (95% CI 3-5) weeks in the popliteal group (P = 0.98). All symptoms resolved by 14 weeks postprocedure. CONCLUSION: Blocking the sciatic nerve at a more distal site after a failed subgluteal sciatic nerve block does not appear to influence the incidence or duration of neurologic sequelae.

Acquisition of critical intraoperative event management skills in novice anesthesiology residents by using high-fidelity simulation-based training.

BACKGROUND: Early acquisition of critical competencies by novice anesthesiology residents is essential for patient safety, but traditional training methods may be insufficient. The purpose of this study was to determine the effectiveness of high-fidelity simulation training of novice residents in the initial management of critical intraoperative events. METHODS: Twenty-one novice residents participated in this 6-week study. Three hypoxemia and three hypotension scenarios were developed and corresponding checklists were validated. Residents were tested in all scenarios at baseline (0 weeks) and divided into two groups, using a randomized crossover study design. Group 1 received simulation-based training in hypoxemic events, whereas Group 2 was trained in hypotensive events. After intermediate (3 weeks) testing in all scenarios, the groups switched to receive training in the other critical event. Final testing occurred at 6 weeks. Raters blinded to subject identity, group assignment, and test date scored videotaped performances by using checklists. The primary outcome measure was composite scores for hypoxemia and hypotension scenarios, which were compared within and between groups. RESULTS: Baseline performance between groups was similar. At the intermediate evaluation, the mean hypoxemia score was higher in Group 1 compared with Group 2 (65.5% vs. 52.4%, 95% CI of difference 6.3-19.9, P < 0.003). Conversely, Group 2 had a higher mean hypotension score (67.4% vs. 45.5%, 95% CI of difference 14.6-29.2, P < 0.003). At Week 6, the scores between groups did not differ. CONCLUSIONS: Event-specific, simulation-based training resulted in superior performance in scenarios compared with traditional training and simulation-based training in an alternate event.

Ultrasound-assisted and evoked motor response stimulation of the deep peroneal nerve.

BACKGROUND: We performed an observational volunteer study to document an ultrasound-guided evoked motor response blockade of the deep peroneal nerve. METHODS: Sixteen volunteers had deep peroneal nerve blocks in each foot. After visualization of the artery and the deep peroneal nerve with an ultrasound, the nerve was stimulated with a nerve stimulator. Evoked motor responses and/or paresthesia were noted before injection of the local anesthetic. RESULTS: Any evoked motor response (extension of the toes or muscle contractions on the dorsum of the lateral aspect of the foot) or elicitation of paresthesia resulted in complete sensory blockade of the web between the big toe and second toe. CONCLUSIONS: Visualization of the deep peroneal nerve with ultrasound followed by elicitation of an evoked motor response, or paresthesia, predicts successful blockade of the deep peroneal nerve.

Early compared with late neuraxial analgesia in nulliparous labor induction: a randomized controlled trial.

OBJECTIVE: To determine whether early initiation of neuraxial analgesia (anesthetic[s] placed around the nerves of the central nervous system) compared with systemic opioid analgesia, followed later in labor by epidural analgesia, increases the rate of cesarean delivery in nulliparas undergoing induction of labor. METHODS: Nulliparas undergoing induction of labor who requested analgesia when cervical dilation was less than 4 cm participated in the study. Patients were randomized to neuraxial (early) or systemic opioid (late) analgesia at the first analgesia request. Patient-controlled epidural analgesia was initiated in the early group at the second analgesia request and in the late group at cervical dilation of 4 cm or greater or at the third analgesia request. The primary outcome was the rate of cesarean delivery. RESULTS: The rate of cesarean delivery was not different between groups (neuraxial [early] 32.7% compared with systemic [late] 31.5%, 95% confidence interval of the difference -3% to 6%, P=.65). A sample size of 30,500 would be required to detect a difference at the observed rate. There were no differences in the mode of vaginal delivery or Apgar scores. Pain scores were significantly lower (median 1 compared with 5 on a 0-10 scale, P<.001) and labor duration shorter (median 528 minutes compared with 569 minutes, P=.047) in the early group. The incidence of reassuring fetal heart rate tracings after analgesia was not different between groups. CONCLUSION: Early-labor neuraxial analgesia does not increase the cesarean delivery rate compared with late epidural analgesia in nulliparas undergoing induction of labor.

Evaluation of a proximal block site and the use of nerve-stimulator-guided needle placement for posterior tibial nerve block.

BACKGROUND: Posterior tibial nerve (PTN) block has traditionally been performed in the para-medial malleolar area without nerve stimulator (NS) guidance. The PTN can also be blocked proximally (7 cm) above the medial malleolus in the subfascial plane between the flexor hallucis longus and flexor digitorum longus tendons. In this study we compared the frequency of successful PTN block at the traditional distal (D) site (2 cm above the medial malleolus) with and without NS guidance. We also compared block success and latency at the D site versus the proximal (P) block site. METHODS: Subjects were randomized to P-NS (n = 45), D-NS (n = 45), or D without NS (n = 45). Levobupivacaine 0.625%, 0.15 mL/kg was used for all blocks. Pinprick sensory anesthesia was evaluated in the distribution of the medial plantar, lateral plantar, and medial calcaneal nerves. PTN block was considered successful if surgical anesthesia was achieved in all PTN distributions. RESULTS: The frequency of successful PTN block was greater for D-NS (100%) and P-NS (93.5%), compared with D (73.3%) (P = 0.02). Median latency to complete block was less for D-NS (8 min, 95% CI 7-9 min) than D (20 min, 95% CI 13-26 min) (P < 0.01) and P-NS (15 min, 95% CI 12-18 min) (P = 0.04). CONCLUSIONS: NS-guided needle placement improves the success and decreases the latency to onset of complete PTN block at the D site. The P approach to PTN block may be a useful alternative to the traditional D site approach, particularly in patients with restricted access to the D site.

Postoperative epidural morphine for postpartum tubal ligation analgesia.

Women undergoing postoperative postpartum tubal ligation (PPTL) often experience considerable pain. We hypothesized that epidural morphine, as part of a multi-modal analgesic regimen, would decrease postoperative pain and the need for systemic analgesia after PPTL. In a double-blinded study, patients were randomized to receive epidural saline or morphine 2 mg, 3 mg, or 4 mg after epidural anesthesia for PPTL. Postoperatively, ibuprofen 600 mg was administered every 6 h and patients could request acetaminophen 325 mg/hydrocodone 10 mg. The primary outcome variable was time to first request for supplemental analgesia. Verbal rating scores for pain and the incidence and severity of side effects were recorded for 24 h. Morphine group subjects requested supplemental analgesia later and received fewer doses compared with the saline group subjects. Peak cramping and incisional verbal rating scores for pain and the area under the verbal rating scores for pain x time curve for cramping pain were less after epidural morphine compared with saline, but there were no differences among morphine groups. Nausea, vomiting, and pruritus occurred more often in all morphine groups and subjects who received morphine 4 mg required treatment for these side effects more frequently than the saline or morphine 2 mg groups. In conclusion, epidural morphine 2 mg as part of a multi-modal analgesic regimen improved analgesia and decreased the need for supplemental analgesics after PPTL. The need to treat side effects with morphine 2 mg was not increased compared to a regimen of oral acetaminophen/opioid/nonsteroidal antiinflammatory analgesics.

Neurologic sequelae after interscalene brachial plexus block for shoulder/upper arm surgery: the association of patient, anesthetic, and surgical factors to the incidence and clinical course.

We determined the incidence, distribution, and resolution of neurologic sequelae and the association with anesthetic, surgical, and patient factors after single-injection interscalene block (ISB) using levobupivacaine 0.625% with epinephrine 1:200,000 in subjects undergoing shoulder or upper arm surgery, or both, in 693 consecutive adult patients. After a standardized ISB, assessments were made at 24 and 48 h and at 2 and 4 wk for anesthesia, hypesthesia, paresthesias, pain/dysesthesias, and motor weakness. Symptomatic patients were monitored until resolution. Subjects reporting pain or discomfort >3 of 10 and those with motor or extending sensory symptoms received diagnostic assessment. Six-hundred-sixty subjects completed 4 wk of follow-up. Fifty-eight neurologic sequelae were reported by 56 subjects. Symptoms were sensory except for two cases of motor weakness (lesions identified distant from the ISB site). Thirty-one sequelae with likely ISB association were reported by 29 subjects, including 14 at the ISB site, 9 at the distal phalanx of thumb/index finger, 7 involving the posterior auricular nerve, and 1 clinical brachial plexopathy. Sequelae not likely associated with the ISB were reported by 27 subjects with symptoms reported in the median (n = 9) and ulnar (n = 4) nerves, surgical neuropraxias (n = 12), and motor weakness (n = 2). Symptoms resolved spontaneously (median 4 wk; range, 2-16 wk) except in the two patients with motor weaknesses and the patient with clinical brachial plexopathy, who received therapeutic interventions. Variables identified as independent predictors of neurologic sequelae likely related to ISB were paresthesia at needle insertion and ISB site pain or bruising at 24 h. In contrast, surgery preformed in the sitting position, as well as ISB site bruising, was identified as a predictor of neurologic sequelae not likely related to ISB. In conclusion, neurologic sequelae after single-injection ISB using epinephrine mainly involve transient minor sensory symptoms.

The risk of cesarean delivery with neuraxial analgesia given early versus late in labor.

BACKGROUND: Epidural analgesia initiated early in labor (when the cervix is less than 4.0 cm dilated) has been associated with an increased risk of cesarean delivery. It is unclear, however, whether this increase in risk is due to the analgesia or is attributable to other factors. METHODS: We conducted a randomized trial of 750 nulliparous women at term who were in spontaneous labor or had spontaneous rupture of the membranes and who had a cervical dilatation of less than 4.0 cm. Women were randomly assigned to receive intrathecal fentanyl or systemic hydromorphone at the first request for analgesia. Epidural analgesia was initiated in the intrathecal group at the second request for analgesia and in the systemic group at a cervical dilatation of 4.0 cm or greater or at the third request for analgesia. The primary outcome was the rate of cesarean delivery. RESULTS: The rate of cesarean delivery was not significantly different between the groups (17.8 percent after intrathecal analgesia vs. 20.7 percent after systemic analgesia; 95 percent confidence interval for the difference, -9.0 to 3.0 percentage points; P=0.31). The median time from the initiation of analgesia to complete dilatation was significantly shorter after intrathecal analgesia than after systemic analgesia (295 minutes vs. 385 minutes, P<0.001), as was the time to vaginal delivery (398 minutes vs. 479 minutes, P<0.001). Pain scores after the first intervention were significantly lower after intrathecal analgesia than after systemic analgesia (2 vs. 6 on a 0-to-10 scale, P<0.001). The incidence of one-minute Apgar scores below 7 was significantly higher after systemic analgesia (24.0 percent vs. 16.7 percent, P=0.01). CONCLUSIONS: Neuraxial analgesia in early labor did not increase the rate of cesarean delivery, and it provided better analgesia and resulted in a shorter duration of labor than systemic analgesia.

Efficacy of a prophylactic epidural blood patch in preventing post dural puncture headache in parturients after inadvertent dural puncture.

BACKGROUND: Postdural puncture headache (PDPH) occurs in up to 80% of parturients who experience inadvertent dural puncture during epidural catheter placement. The authors performed a randomized double blind study to assess the effect of prophylactic epidural blood patch on the incidence of PDPH and the need for therapeutic epidural blood patch. METHODS: Sixty-four parturients who incurred inadvertent dural puncture were randomized to receive a prophylactic epidural blood patch with 20 ml autologous blood (prophylactic epidural blood patch group) or a sham patch (sham group). Subjects were evaluated daily for development of PDPH for a minimum of 5 days after dural puncture. Those who developed a PDPH were followed daily for a minimum of 3 days after resolution of the headache. Subjects with moderate headaches who reported difficulties performing childcare activities and all those with severe headaches were advised to receive a therapeutic epidural blood patch. RESULTS: Eighteen of 32 subjects in each group (56%) developed PDPH. Therapeutic blood patch was recommended in similar numbers of patients in each group. The groups had similar onset time of PDPH, median peak pain scores, and number of days spent unable to perform childcare activities as a result of postural headache. The median duration of PDPH, however, was shorter in the prophylactic epidural blood patch group. CONCLUSIONS: A decrease in the incidence of PDPH or the need for criteria-directed therapeutic epidural patch was not detected when a prophylactic epidural blood patch was administered to parturients after inadvertent dural puncture. However, prophylactic epidural blood patch did shorten the duration of PDPH symptoms.

Nerve stimulator-assisted evoked motor response predicts the latency and success of a single-injection sciatic block.

Variable onset latency of single-injection sciatic nerve block (SNB) may result from drug deposition insufficiently close to all components of the nerve. We hypothesized that this variability is caused by the needle tip position relative to neural components, which is objectified by the type of evoked motor response (EMR) elicited before local anesthetic injection. One-hundred ASA I-II patients undergoing reconstructive ankle surgery received infragluteal-parabiceps SNB using 0.4 mL/kg (maximum 35 mL) of levobupivacaine 0.625%. The end-point for injection was the first elicited EMR: inversion (I), plantar flexion (PF), dorsiflexion (DF), or eversion (E) at 0.2-0.4 mA. The frequencies of the EMRs were: I 40%, PF 43%, E 14%, and DF 3%. SNB was considered complete if both tibial and common peroneal nerves were blocked and failed if either analgesia to pinprick was not observed at 30 min or anesthesia at 60 min. Patients with an EMR of I demonstrated shorter mean times (+/-95% confidence interval [CI]) to complete the block with 8.5 (95% CI, 6.2-10.8) min compared to 27.0 (95% CI, 20.6-33.4) min after PF (P < 0.001) and 30.4 (95% CI, 24.9-35.8) min after E (P < 0.001). No rescue blocks were required in group I compared with 24% (P = 0.001) and 71% (P < 0.001) of patients in groups PF and E, respectively. We conclude that EMR type during nerve stimulator-assisted single-injection SNB predicts latency and success of complete SNB because the observed EMR is related to the positioning of the needle tip relative to the tibial and common peroneal nerves.

Infragluteal-parabiceps sciatic nerve block: an evaluation of a novel approach using a single-injection technique.

UNLABELLED: Clinical use of the sciatic nerve block (SNB) has been limited by technical difficulties in performing the block using standard approaches, substantial patient discomfort during the procedure, or the need for two injections to block the tibial and peroneal nerves. In this report, we describe a single-injection method for SNB using an infragluteal-parabiceps approach, where the nerve is located along the lateral border of the biceps femoris muscle. SNB was performed in the prone or lateral decubitus position. The needle was positioned (average depth, 56 +/- 15 mm) to the point where plantar flexion (53%) or inversion (45%) of the ipsilateral foot was obtained at < or =0.4 mA. Levobupivacaine 0.625% with epinephrine (1:200:000) was administered at a dose of 0.4 mL/kg. The procedure was completed in 6 +/- 3 min. Discomfort during block placement was treated with fentanyl 50-100 microg in 24% of patients. Complete sensory loss and motor paralysis occurred in 92% of subjects at a median time of 10 (range, 5-25) min after injection. Compared with plantar flexion, foot inversion was associated with a more frequent incidence (86% versus 100%), and shorter latency for both sensory loss and motor paralysis of the peroneal, tibial, and sural nerves. There were no immediate or delayed complications. We conclude that the infragluteal-parabiceps approach to SNB is reliable, efficient, safe, and well tolerated by patients. IMPLICATIONS: Sciatic nerve block using the infragluteal-parabiceps approach produces sensory loss and motor paralysis after a single 0.4 mL/kg injection of levobupivacaine 0.625% with epinephrine (1:200,000) in >90% of patients. The approach is reliable, uses consistent soft-tissue landmarks, is not typically painful, and does not produce significant complications.