Cognitive deficits after general anaesthesia in animal models: a scoping review.

BACKGROUND: It remains controversial whether general anaesthetic drugs contribute to perioperative neurocognitive disorders in adult patients. Preclinical studies have generated conflicting results, likely because of differing animal models, study protocols, and measured outcomes. This scoping review of preclinical studies addressed the question: 'Do general anaesthetic drugs cause cognitive deficits in adult animals that persist after the drugs have been eliminated from the brain?' METHODS: Reports of preclinical studies in the MEDLINE database published from 1953 to 2021 were examined. A structured review process was used to assess original studies of cognitive behaviours, which were measured after treatment (≥24 h) with commonly used general anaesthetic drugs in adult animals. RESULTS: The initial search yielded 380 articles, of which 106 were fully analysed. The most frequently studied animal model was male (81%; n=86/106) rodents (n=106/106) between 2-3 months or 18-20 months of age. Volatile anaesthetic drugs were more frequently studied than injected drugs, and common outcomes were memory behaviours assessed using the Morris water maze and fear conditioning assays. Cognitive deficits were detected in 77% of studies (n=82/106) and were more frequent in studies of older animals (89%), after inhaled anaesthetics, and longer drug treatments. Limitations of the studies included a lack of physiological monitoring, mortality data, and risk of bias attributable to the absence of randomisation and blinding. CONCLUSIONS: Most studies reported cognitive deficits after general anaesthesia, with age, use of volatile anaesthetic drugs, and duration of anaesthesia as risk factors. Recommendations to improve study design and guide future research are presented.

Effectiveness of a Transesophageal Echocardiography Course.

BACKGROUND: Transesophageal echocardiography has important applications for the management of the critically ill patient. There is a need to develop effective training programs for the critical care community in acquiring skill at critical care transesophageal echocardiography. OBJECTIVE: We studied the effectiveness of a 1-day simulation-based course that focused on the acquisition of skill in the performance of critical care transesophageal echocardiography. METHODS: Learners received training in image acquisition with a transesophageal simulator and training in image interpretation in small group sessions. Skill at image acquisition and image interpretation was assessed at the beginning and at the completion of the course. RESULTS: There were 27 learners who attended the course. Pre and post knowledge scores were 55 (19; mean [SD]) and 88 (9; P < .0005), respectively. Pre and post image acquisition scores were 3.6 (3.7) and 9.9 (0.3; P < .0001), respectively. CONCLUSIONS: A 1-day course in critical care transesophageal echocardiography that combined case-based image interpretation with image acquisition training using a simulator improved technical skills and knowledge base.

Transversus abdominis plane block compared with wound infiltration for postoperative analgesia following Cesarean delivery: a systematic review and network meta-analysis.

PURPOSE: This systematic review and network meta-analysis (NMA) compared postoperative analgesic efficacy of transversus abdominis plane (TAP) blocks with that of wound infiltration for Cesarean delivery (CD) without long-acting neuraxial opioid administration. METHODS: We sought randomized-controlled trials comparing TAP vs wound infiltration, and inactive control vs either TAP or wound infiltration. Wound infiltration included single-dose infiltration (WI), or continuous infusion via a catheter (WC). The primary outcome was 24 hr opioid consumption. Secondary outcomes included 12 and 24 hr pain scores (resting and movement), time to first analgesia request, incidence of postoperative nausea and vomiting (PONV), maternal sedation, and pruritus. We performed a NMA incorporating both direct and indirect comparisons and reported standardized mean differences and odds ratios with 95% confidence intervals for continuous and dichotomous outcomes. RESULTS: Forty-two studies were included, comprising 2,906 participants. Transversus abdominis plane blocks and WC were associated with significantly lower 24 hr opioid consumption than inactive controls, but there were no significant differences between WI and inactive controls. There was no statistically significant difference in 24 hr opioid consumption between TAP blocks and WC or WI techniques. The network ranking of treatments was TAP block, followed by WC or WI. No significant differences were shown between TAP, WC, and WI groups for 24 hr pain scores, time to first analgesia, PONV, sedation, and pruritus. Quality of evidence was moderate for most of the outcomes assessed. CONCLUSION: In the absence of long-acting neuraxial opioid after CD, single-dose TAP blocks and WC are effective opioid-sparing strategies.

RéSUMé: OBJECTIF: Cette revue systématique et méta-analyse en réseau (MAR) ont comparé l'efficacité analgésique postopératoire de blocs du plan du muscle transverse de l'abdomen (bloc TAP, Transversus Abdominis Plane) à celle d'infiltrations de l'incision chirurgicale après un accouchement par césarienne et en l'absence d'administration d'opioïdes neuraxiaux à action prolongée. MéTHODE: Nous avons examiné les études randomisées contrôlées comparant un bloc TAP à une infiltration de l'incision, et les comparateurs inactifs vs soit un bloc TAP ou une infiltration de l'incision. Les infiltrations de l'incision comprenaient des infiltrations à dose unique ou des perfusions continues via un cathéter. Le critère d'évaluation principal était la consommation d'opioïdes en 24 heures. Les critères d'évaluation secondaires comprenaient les scores de douleur à 12 et 24 h (au repos et avec mouvement), le délai jusqu'à la première demande d'analgésie, l'incidence de nausées et vomissements postopératoires (NVPO), la sédation maternelle et le prurit. Nous avons réalisé une MAR intégrant des comparaisons directes et indirectes et rapportons les différences moyennes standardisées et les rapports de cotes avec des intervalles de confiance de 95 % pour les critères d'évaluation continus et dichotomiques. RéSULTATS: Quarante-deux études ont été incluses, comprenant 2906 participantes. Les blocs TAP et les infiltrations par cathéter étaient associés à une consommation d'opioïdes en 24 heures significativement plus faible que les comparateurs inactifs, mais aucune différence significative n'a été observée entre infiltrations uniques et comparateurs inactifs. Aucune différence statistiquement significative dans la consommation d'opioïdes en 24 heures n'a été observée entre les blocs TAP et les techniques d'infiltration par perfusion continue ou unique. Le classement en réseau des traitements est : les blocs TAP, suivi par les infiltrations par perfusion continue ou unique. Aucune différence significative n'a été démontrée dans les scores de douleur à 24 h, le délai jusqu'à la première analgésie, les NVPO, la sédation et le prurit entre les groupes TAP, infiltration par perfusion continue et infiltration unique. La qualité des données probantes était modérée pour la plupart des critères évalués. CONCLUSION: En l'absence d'un opioïde neuraxial à action prolongée après un accouchement par césarienne, les blocs TAP en dose unique et les infiltrations par perfusion continue sont des stratégies efficaces pour réduire la consommation d'opioïdes.

Oral vs intravenous iron therapy for postpartum anemia: a systematic review and meta-analysis.

OBJECTIVE: To perform a systematic review of randomized trials comparing oral vs intravenous (IV) iron therapy to treat postpartum anemia. DATA SOURCES: Data sources were as follows: PubMed (1972-2017); Cochrane Central Register of Controlled Trials, CENTRAL (1972-2017); CINAHL (1972-2017); Web of Science; Excerpta Medica Database, and EMBASE (1972-2017). STUDY ELIGIBILITY CRITERIA: We included randomized trials comparing oral vs IV iron monotherapy to treat postpartum anemia (classified as a hemoglobin <12 g/dL). STUDY APPRAISAL AND SYNTHESIS METHODS: Study quality was assessed with the Cochrane risk of bias assessment tool. The primary outcome was hemoglobin concentration at 6 weeks postpartum. Secondary outcomes included hemoglobin concentration at 1-5 weeks postpartum, ferritin concentration at 1-6 weeks postpartum, and maternal adverse outcomes. For meta-analysis, mean differences and odds ratios using a random effects model were calculated. Risk of heterogeneity was reported as I2. RESULTS: A total of 15 randomized trials met our inclusion criteria (n = 1001 and 1 181 women receiving oral iron and IV iron, respectively); 4 studies reported data for our primary outcome. We observed higher postpartum week 6 hemoglobin concentrations in the IV iron group compared to the oral iron group (mean difference, 0.9 g/dL; 95% confidence interval (CI), 0.4-1.3; P = .0003). Compared to oral iron, women receiving IV iron had higher hemoglobin concentrations at postpartum weeks 1, 2, and 3; higher ferritin concentrations at postpartum weeks 1, 2, 4, and 6; an increased likelihood of skin flushing (odds ratio [OR], 6.95; 95% CI, 1.56-31.03; P = .01; I2 = 0%); and a decreased likelihood of constipation (OR, 0.08; 95% CI, 0.03-0.21; P < .00001, I2 = 27%) and dyspepsia (OR, 0.07; 95% confidence interval, 0.01-0.42; P = .004; I2 = 0%). The reported event rate for anaphylaxis among women receiving IV iron was 0.6%. CONCLUSION: In this systematic review, among women with postpartum anemia, hemoglobin concentrations at 6 weeks postpartum were almost 1 g/dL higher in women who received IV iron compared to oral iron. The safety profile of IV iron was also reassuring. Given the weaker hemoglobin response and higher risk of gastrointestinal side effects with oral iron use, our findings suggest that IV iron be considered as a viable treatment option for postpartum iron deficiency anemia.

The Effect of Intrathecal Morphine Dose on Outcomes After Elective Cesarean Delivery: A Meta-Analysis.

BACKGROUND: The intrathecal morphine dose achieving optimal analgesia for cesarean delivery while minimizing side effects has not yet been deduced. In this meta-analysis, our objective was to determine whether low- or high-dose intrathecal morphine provides acceptable duration and intensity of analgesia with fewer side effects. METHODS: A literature search (PubMed, EMBASE, MEDLINE, Scopus, Web of Science, and CINAHL) was performed to identify randomized controlled trials involving patients undergoing elective cesarean delivery under spinal anesthesia comparing low-dose (LD; 50-100 µg) morphine with higher dose (HD; >100-250 µg). The primary outcome was the time for first request for supplemental analgesia. The secondary outcomes included pain scores, morphine use, maternal side effects (vomiting and pruritus), and Apgar scores. Mean differences (MDs) and odds ratios (ORs) were calculated using random effects modeling with 95% confidence intervals (CIs). RESULTS: Eleven articles met our inclusion criteria. Four hundred eighty patients were recruited in all study groups (233 patients in the HD and 247 in the LD groups). The mean time to first analgesic request was longer (MD, 4.49 hours [95% CI, 1.85-7.13]; P = 0.0008) in the HD group compared with the LD group. Pain scores (0-100 scale) at 12 hours (MD, 2.54 [95% CI, -2.55 to 7.63]; P = 0.33) as well as morphine consumption at 24 hours (MD, 1.31 mg [95% CI, -3.06 to 7.31]; P = 0.42) were not significantly different. The incidence of nausea or vomiting (OR, 0.44 [95% CI, 0.27-0.73]; P = 0.002) and pruritus (OR, 0.34 [95% CI, 0.20-0.59]; P = 0.0001) was lower in the LD group. The incidence of Apgar scores <7 at 1 minute was not different between groups (OR, 1.11 [95% CI, 0.06-20.49]; P = 0.94). CONCLUSIONS: This meta-analysis shows that HDs of intrathecal morphine prolong analgesia after cesarean delivery compared with lower doses. The MD of 4.5 hours (95% CI, 1.9-7.1 and 99% CI, 1.0-8.2 hours) of pain relief must be balanced against the increased risk of maternal pruritus and vomiting. Results from this study can be used by clinicians to weigh the benefits and potential side effects of using HDs of intrathecal morphine for cesarean delivery.

Will the Real Benefits of Single-Shot Interscalene Block Please Stand Up? A Systematic Review and Meta-Analysis.

BACKGROUND: Interscalene block (ISB) can provide pain relief after shoulder surgery, but a reliable quantification of its analgesic benefits is lacking. This meta-analysis examines the effect of single-shot ISB on analgesic outcomes during the first 48 hours after shoulder surgery. METHODS: We retrieved randomized and quasirandomized controlled trials examining the analgesic benefits of ISB compared with none in shoulder surgery. Severity of postoperative pain measured on a visual analog scale (10 cm scale, 0 = no pain, 10 = worst pain) at rest at 24 hours was the designated primary outcome. Secondary outcomes included pain severity at rest and with motion at 2, 4, 6, 8, 12, 16, 32, 36, 40, and 48 hours postoperatively. Opioid consumption, postoperative nausea and vomiting, patient satisfaction with pain relief, and postanesthesia care unit and hospital discharge time were also assessed. RESULTS: A total of 23 randomized controlled trials, including 1090 patients, were analyzed. Patients in the ISB group had more severe postoperative pain at rest by a weighed mean difference (95% confidence interval) of 0.96 cm (0.08-1.83; P = 0.03) at 24 hours compared with no ISB, but there was no difference in pain severity beyond that point. The duration of pain relief at rest and with motion after ISB were 8 and 6 hours, respectively, with a corresponding weighed mean difference in visual analog scale pain scores (99% confidence interval) of -1.59 cm (-2.60 to -0.58) and -2.20 cm (-4.34 to -0.06), respectively, with no additional pain relief benefits beyond these points. ISB reduced postoperative opioid consumption up to 12 hours, decreased postoperative nausea and vomiting at 24 hours, and expedited postanesthesia care unit and hospital discharge. The type, dose, and volume of local anesthetic used did not affect the results. CONCLUSIONS: ISB can provide effective analgesia up to 6 hours with motion and 8 hours at rest after shoulder surgery, with no demonstrable benefits thereafter. Patients who receive an ISB can suffer rebound pain at 24 hours but later experience similar pain severity compared with those who do not receive an ISB. ISB can also provide an opioid-sparing effect and reduce opioid-related side effects in the first 12 and 24 hours postoperatively, respectively. These findings are useful to inform preoperative risk-benefit discussions regarding ISB for shoulder surgery.

Anesthetic considerations for high order cesarean sections: a prospective cohort study.

BACKGROUND: In a previous retrospective study we demonstrated that perioperative complications occurred in a minority of high order repeat cesarean sections (HOR-C/S). In this prospective study we compared the incidence of complications in patients who have had four or more cesarean sections to those that had three or less. METHODS: This was a prospective, observational cohort study of parturients undergoing C/S at a single tertiary care hospital over a 1 year period. We compared the incidence of conversion from regional to general anesthesia, duration of surgery and incidence of major blood loss in HOR-C/S to control. RESULTS: We studied a total of 831 parturients, 129 underwent HOR-C/S. The incidence of conversion from regional to general anesthesia was similar in both groups (RR = 0.97, 95% CI 0.2, 4.3). The median duration of surgery was 40 min (range 10-145 min) in the HOR-C/S group and 30 min (range 10-150 min) in the control group (p < 0.001). The incidence of prolonged surgery was increased in the HOR-C/S group (RR = 3.6, 95% CI 2.4, 5.4). The incidence of intraoperative blood transfusion was higher in the HOR-C/S group (RR = 3.4, 95% CI 1.1, 10.2). CONCLUSIONS: Patients who have HOR-C/S are more likely to have prolonged surgery and require blood transfusion than controls. However, in our population, this was not associated with an increased incidence of conversion from regional to general anesthesia. Provided causes of severe hemorrhage such as abnormal placentation have been ruled out, HOR-C/S is not an absolute contraindication to regional block.

Case report: Rhabdomyolysis in morbidly obese patients: anesthetic considerations.

PURPOSE: We report the presentation and management of rhabdomyolysis involving shoulder girdle and upper arm muscles in a morbidly obese patient after prolonged laparoscopic surgery. CLINICAL FEATURES: A 41-yr-old morbidly obese woman presented for laparoscopic abdominal hysterectomy. She had hypertension and type II diabetes which were controlled on regular medications. She also had obstructive sleep apnea. Her clinical examination and investigations revealed no abnormality except morbid obesity (body mass index 54 kg·m(-2)) and left ventricular hypertrophy on transthoracic echocardiogram. Standard general anesthesia was administered under baseline non-invasive monitors. Succinylcholine was used to secure the airway during anesthetic induction. Surgery was performed with the patient positioned with a 15° head-down tilt, and it took six hours to complete the procedure as technical difficulty was encountered due to her body habitus. Her trachea was extubated and she was transferred to the postanesthetic care unit (PACU) without incident. In the PACU, the patient complained of severe bilateral arm pain and weakness an hour after surgery. On physical examination, she exhibited limited movement of her arms against gravity while complaining of tenderness in her shoulder girdle muscles and both arms. Clinical suspicion of rhabdomyolysis based on her signs and symptoms was confirmed by an elevated serum creatinine kinase (CK) of 18,392 IU·L(-1) and serum potassium of 5.3 mmol·L(-1). Intravenous crystalloids and mannitol were administered for 24 hr for renal protection, and her clinical symptoms and serum CK levels improved over seven days. The patient was discharged to home on the tenth postoperative day, and she continued to improve over the three-month follow-up period. CONCLUSIONS: Morbidly obese patients who undergo prolonged surgery are at risk for rhabdomyolysis, and early diagnosis and therapy are required to prevent severe complications.

The effect of low concentrations versus high concentrations of local anesthetics for labour analgesia on obstetric and anesthetic outcomes: a meta-analysis.

INTRODUCTION: The influence that different concentrations of labour epidural local anesthetic have on assisted vaginal delivery (AVD) and many obstetric outcomes and side effects is uncertain. The purpose of this meta-analysis was to determine whether local anesthetics utilized at low concentrations (LCs) during labour are associated with a decreased incidence of AVD when compared with high concentrations (HCs). METHODS: We searched PubMed, Ovid EMBASE, Ovid MEDLINE, CINAHL, Scopus, clinicaltrials.gov, and Cochrane databases for randomized controlled trials of labouring patients that compared LCs (defined as ≤ 0.1% epidural bupivacaine or ≤ 0.17% ropivacaine) of epidural local anesthetic with HCs for maintenance of analgesia. The primary outcome was AVD and secondary outcomes included Cesarean delivery, duration of labour, analgesia, side effects (nausea and vomiting, motor block, hypotension, pruritus, and urinary retention), and neonatal outcomes. The odds ratios (OR) or weighted mean differences (WMD) and 95% confidence intervals (CI) were calculated using random effects modelling. An OR < 1 or a WMD < 0 favoured LCs. RESULTS: Eleven studies met our criteria (eight bupivacaine and three ropivacaine studies), providing 1,145 patients in the LCs group and 852 patients in the HCs group for analysis of the primary outcome. Low concentrations were associated with a reduction in the incidence of AVD (OR = 0.70; 95% CI 0.56 to 0.86; P < 0.001). There was no difference in the incidence of Cesarean delivery (OR 1.05; 95% CI 0.82 to 1.33; P = 0.7). The LCs group had less motor block (OR 3.9; 95% CI 1.59 to 9.55; P = 0.003), greater ambulation (OR 2.8; 95% CI 1.1 to 7.14; P = 0.03), less urinary retention (OR 0.42; 95% CI 0.23 to 0.73; P = 0.002), and a shorter second stage of labour (WMD -14.03; 95% CI -27.52 to -0.55; P = 0.04) compared with the HCs group. There were no differences between groups in pain scores, maternal nausea and vomiting, hypotension, fetal heart rate abnormalities, five-minute Apgar scores, and need for neonatal resuscitation. One-minute Apgar scores < 7 favoured the HCs group (OR 1.53; 95% CI 1.07 to 2.21; P = 0.02), and there was more pruritus in the LCs group (OR 3.36; 95% CI 1.00 to 11.31; P = 0.05). CONCLUSION: When compared with HCs of local anesthetics, the use of LCs for labour epidural analgesia reduces the incidence of AVD. This may be due to a reduction in the amount of local anesthetic used and the subsequent decrease in motor blockade. We therefore recommend the use of LCs of local anesthetics for epidural analgesia to optimize obstetric outcome.

Elective cesarean delivery in non-dialyzed parturient with chronic renal failure.

Chronic renal failure is rare in pregnancy and often results in significant maternal and neonatal morbidity. When possible, preoperative dialysis is useful to optimize fluid and electrolyte balance. We describe the perioperative management of a parturient who persistently refused dialysis, had an uneventful cesarean delivery under graded epidural anesthesia.

Anesthetic considerations of parturients with obesity and obstructive sleep apnea.

Obstructive sleep apnea (OSA) is characterized by upper airway collapse and obstruction during sleep. It is estimated to affect nearly 5% of the general female population. Obesity is often associated with OSA. The physiological changes associated with pregnancy may increase the severity of OSA with a higher risk of maternal and fetal morbidity. However, very few parturients are diagnosed during pregnancy. These undiagnosed parturients pose great challenge to the attending anaesthesiologist during the perioperative period. Parturients at risk should be screened for OSA, and if diagnosed, treated. This review describes the anaesthetic concerns in obese parturients at risk for OSA presenting to the labor and delivery unit.

Labor neuraxial analgesia and breastfeeding: An updated systematic review.

INTRODUCTION: There have been numerous reports studying the effect of neuraxial analgesia on breastfeeding success, but the results are inconsistent. METHODS: We performed a literature search in various databases for studies comparing neuraxial analgesia to non-neuraxial or no analgesia. Outcomes were the percentage of women breastfeeding fully or mixed with formula. Where possible, nulliparous parturients were analyzed separately. We conducted an analysis excluding studies of serious and critical risk of bias. Odds ratios and 95% confidence intervals were calculated. RESULTS: We included 15 studies (13 observational studies, 1 secondary analysis of a randomized controlled trial, 1 case-control study) with 16,112 participants. Overall, there were 6 studies that found no difference between groups, 6 studies that showed a significantly lower incidence of breastfeeding in the neuraxial group and 3 studies finding mixed results (at some time-points statistically significant and at some time-point statistically non-significant results). In nulliparous only studies, 2 found no difference between study groups, 1 found a lower breastfeeding rate in the neuraxial group and 3 studies showed mixed results. Excluding studies with a serious and critical risk of bias, 1 study found no difference between study groups, 3 studies found a decrease of breastfeeding rates in the neuraxial group, and 1 study showed mixed results. DISCUSSION: In our review we found a high disparity in results. One reason is probably the high potential of confounding (immediate skin to skin placement, maternity leave etc.). Education programs and breastfeeding support are likely more important in determining long term breastfeeding success.

Focused review: ropivacaine versus bupivacaine for epidural labor analgesia.

Neuraxial analgesia is frequently administered to women in labor. For many years, bupivacaine has been used because of its long duration of action, lack of excessive motor block, and minimal fetal and neonatal effects. However, bupivacaine is one of the most cardiotoxic local anesthetics in current use and motor block is still a problem. Many local anesthetics such as bupivacaine exist in 2 forms, levorotatory and dextrorotatory. Ropivacaine, an amide local anesthetic produced in the pure levorotatory form addresses some of the concerns related to bupivacaine. In this article, we present the literature comparing ropivacaine and bupivacaine to determine whether there is an advantage to using one of these local anesthetics for labor analgesia. We found that there is no advantage to the routine use of ropivacaine for labor analgesia.

Preload or coload for spinal anesthesia for elective Cesarean delivery: a meta-analysis.

BACKGROUND: Hypotension following spinal anesthesia for Cesarean delivery is common. Fluid loading is recommended to prevent hypotension, but preload is often ineffective. In non-pregnant patients, coloading has been shown to better maintain cardiac output after spinal anesthesia. The purpose of this meta-analysis was to determine whether the timing of the fluid infusion, before (preload) or during (coload) induction of spinal anesthesia for Cesarean delivery, influences the incidence of maternal hypotension or neonatal outcome. METHODS: We retrieved randomized controlled trials that compared a fluid preload with coload in patients undergoing spinal anesthesia for elective Cesarean delivery. We graded the articles for quality of reporting (maximum score = 5) and recorded the incidence of hypotension, lowest blood pressure, the incidence of maternal nausea and vomiting, umbilical cord pH, and Apgar scores. We combined the results using random effects modelling. RESULTS: We retrieved eight studies comprised of 518 patients. The median quality score for the published studies was three. The incidence of hypotension in the coload group was 159/268 (59.3%) compared with 156/250 (62.4%) in the preload group (odds ratio [OR] = 0.93; 95% confidence interval [CI] 0.54-1.6). There were no significant differences between groups in any of the other outcomes. CONCLUSIONS: It is unnecessary to delay surgery in order to deliver a preload of fluid. Regardless of the fluid loading strategy, the incidence of maternal hypotension is high. Prophylactic or therapeutic vasopressors may be required in a significant proportion of patients.

The use of ultrasound for lumbar spinous process identification: A pilot study.

BACKGROUND: Clinical identification of lumbar spinous processes is inaccurate in most patients. The purpose of this study was to determine the number of patients required to train anesthesiologists in the use of ultrasound imaging to accurately identify the lumbar spinous processes. METHODS: In this pilot study, two anesthesiologists studied patients scheduled for a diagnostic computed tomography (CT) scan, including the lumbar spine. Before the CT scan, the anesthesiologist completed a systematic ultrasound scan of the lumbar spine and placed a radio-opaque marker at a designated level. The actual level was determined by a radiologist after reviewing the CT scans. The primary outcome was the number of procedures each anesthesiologist needed (by cumulative sum analysis) to be able to identify the designated spinous process 90% of the time. Secondary outcomes included the overall success rate, the magnitude of the failures (number of segments from the designated spinous process), and the incidence of spinal anomalies and their effect on reliability. RESULTS: We studied 74 patients. One anesthesiologist required 36 patients to meet reliability criteria, whereas the other required 22 patients. The overall accuracy rate was 68%. There were only two patients where the marker was placed more than one segment from the designated spinous process. The incidence of lumbar spine anomalies was 6.8% (n = 5), and 80% (n = 4) of these were associated with inaccurate marker placement. CONCLUSIONS: It is possible to use ultrasound scanning to accurately identify the lumbar spinous processes in unselected patients. This result suggests that, with appropriate training, this tool can be used to enhance the accuracy of needle placement during neuraxial techniques.