High Neuraxial Block in Obstetrics: A 2.5-Year Nationwide Surveillance Approach in the Netherlands

BACKGROUND

High neuraxial block is a rare but serious adverse event in obstetric anesthesia that can ultimately lead to respiratory insufficiency and cardiac arrest. Previous reports on its incidence are limited to populations in the United Kingdom and the United States. Little is known about the incidence and clinical features of high neuraxial block in the Netherlands, where the presence of anesthesiologists in the labor and delivery unit is comparatively lower. We aimed to assess the incidence and clinical features of high neuraxial block in obstetrics and to formulate ways to improve obstetric anesthesia on a national level.

METHODS

This nationwide, prospective, population-based cohort study was designed to identify cases of high neuraxial block requiring ventilatory support (with supraglottic airway device or tracheal intubation) or cardiopulmonary resuscitation between November 2019 and May 2022. Cases were prospectively collected using the Netherlands Obstetric Surveillance System (NethOSS) in all hospitals with a maternity unit. Complete case file copies were obtained to determine risk factors and clinical course.

RESULTS

During the study period, 5 cases of high neuraxial block requiring tracheal intubation were identified. The estimated incidence of high neuraxial block requiring tracheal intubation was 1 in 29,770 neuraxial procedures in labor (95% confidence interval, 1:12,758-1:91,659). Three of 5 identified cases occurred in the operating room after single-shot spinal anesthesia for Cesarean delivery after epidural analgesia in labor. One case developed in the labor ward due to an inadvertent intrathecal or subdural catheter placed for labor analgesia. The fifth case followed single-shot spinal anesthesia for elective Cesarean delivery. All 5 patients were successfully extubated in the operating room after Cesarean delivery, without the need for intensive care admission. There were no cardiac arrests and no neonatal deaths.

CONCLUSIONS

High neuraxial block requiring tracheal intubation is a rare but impactful complication in obstetric anesthesia, potentially affecting both mother and fetus. Spinal anesthesia after epidural analgesia in labor is a common cause of high neuraxial block. Meticulous follow-up of epidurals in labor facilitates conversion to surgical anesthesia and may therefore reduce the need for spinal anesthesia after epidural analgesia. Large-scale surveillance systems in obstetric anesthesia are needed to identify those at risk, as well as to formulate further strategies to mitigate this burden.

Anesthetic management of patients with class 3 obesity undergoing elective Cesarean delivery: a single-centre historical cohort study

PURPOSE

The preferred neuraxial anesthetic technique for patients with class 3 obesity undergoing elective Cesarean delivery is still under debate. We aimed to describe the anesthetic technique used in our tertiary institution across body mass index (BMI) groups and different surgical incisions.

METHOD

In this historical cohort study, we reviewed medical records of patients with a BMI ≥ 40 kg·m-2 undergoing elective Cesarean delivery between July 2014 and December 2020. We collected data on patient characteristics, anesthetic and surgical technique, and procedural times. For data analysis, we stratified patients by BMI into three different groups: 40.0-49.9 kg·m-2, 50.0-59.9 kg·m-2, and ≥ 60.0 kg·m-2.

RESULTS

We included 396 deliveries, distributed as follows: 258 with a BMI 40.0-49.9 kg·m-2, 112 with a BMI 50.0-59.9 kg·m-2, and 26 with a BMI ≥ 60.0 kg·m-2. For patients with a BMI 40.0-49.9 kg·m-2, the anesthetic technique of first choice was predominantly spinal anesthesia (71%), whereas for those with a BMI ≥ 60.0 kg·m-2, spinal anesthesia was never used as the anesthetic of first choice. With regard to the surgical incision, spinal anesthesia was almost exclusively used for patients undergoing Pfannenstiel incision and was rarely used for a higher supra- or infraumbilical transverse or midline incision. The overall incidence of general anesthesia was low (7/396, 1.8%). Anesthetic time, surgical time, and operating room time increased almost twofold in patients with a BMI ≥ 60.0 kg·m-2 compared with those with a BMI of 40.0-49.9 kg·m-2.

CONCLUSION

Neuraxial anesthesia was successfully used in approximately 98% of patients with class 3 obesity undergoing elective Cesarean delivery. The choice of regional anesthesia technique varied with increasing BMI and with the planned surgical incision. Procedural times increased with increasing BMI. This information should prove useful for comparing anesthetic choices and outcomes in this challenging population.

Color flow Doppler in spinal ultrasound: a novel technique for assessment of catheter position in labor epidurals

BACKGROUND

Ultrasound is commonly used to facilitate epidural catheter placement. However, data are lacking regarding its potential to confirm its position in the epidural space. Our aim was to visualize flow in the epidural space of patients receiving epidural analgesia for labor using color flow Doppler ultrasound.

METHODS

We conducted a prospective observational cohort study that included patients who had delivered vaginally under epidural analgesia. We used a 5-2 mHz curvilinear probe in a left and right paramedian longitudinal oblique view to visualize the anterior and posterior complex at the interspace of epidural catheter insertion, one and two interspaces above and below. At each window, the color flow Doppler function was used to visualize flow within the epidural space on injection of normal saline (1 mL). If no flow was visualized at any interspace, one assessment at the level of insertion was repeated with a 1 mL air/saline mixture. We studied a convenience sample size of 40 patients.

RESULTS

We visualized flow in the epidural space in all 40 patients. Flow was visualized on injection of 1 mL of saline in 37/40 patients (93%). In the remaining 3/40 patients (7%), flow was visualized with an air/saline mixture. Flow on injection of saline was visualized only at the interspace of insertion in 26/37 patients (70%), at the interspace of insertion and one interspace above in 10/37 (27%), or only at one interspace above in 1/37 (3%). Flow was visualized only on the left or on the right paramedian view in 19/37 patients (51%), despite a symmetrical sensory block in all patients.

CONCLUSION

Color flow Doppler ultrasound is a feasible and fast way to determine flow in the epidural space in the obstetric population. Its potential clinical uses are confirmation of the epidural catheter position after placement, as well as troubleshooting of unsatisfactory epidural analgesia. Interestingly, our results suggest that epidural catheters predominantly remain at the interspace of insertion.

TRIAL REGISTRATION NUMBER

NCT05126745.

Predictors and Hospital Outcomes in Pregnant Patients Undergoing Extracorporeal Membrane Oxygenation: A Nationwide Study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is increasingly used in patients with severe cardiorespiratory collapse. Although prior large database reviews of ECMO use in the peripartum population exist, they do not stratify by ECMO indication nor do they include obstetric conditions such as preeclampsia. Our objective was to characterize the incidence, indication-associated mortality, and factors associated with mortality in pregnant patients who underwent ECMO.

METHODS

We examined the United States National Inpatient Sample database to identify hospitalizations for pregnancy from January 1, 2010 to December 31, 2016. We identified pregnant patients who underwent ECMO using International Classification of Diseases ninth and tenth revisions codes. The primary outcome was in-hospital all-cause mortality across pregnant patients who underwent ECMO for any indication. We evaluated the indication for ECMO, incidence, prevalence of risk factors, comorbidities and conditions, and their association with in-hospital mortality.

RESULTS

Fifty-nine of 5'346,517 pregnant patients underwent ECMO during our study period (incidence, 1.1; 95% confidence interval [CI], 0.84-1.4 per 100,000 hospitalizations). Indications for ECMO support included respiratory failure (79.7%), cardiogenic shock (64.4%), or circulatory arrest (25.4%). Most patients (57.6%) had more than 1 indication. The overall in-hospital mortality rate was 30.5%. Mortality was 29.8% in patients with respiratory failure, 39.5% with cardiogenic shock, 46.7% with cardiac arrest, and 42.4% in those with combined diagnoses. Cardiogenic shock was associated with a significantly higher mortality rate and adjusted odds ratio 5.0 (95% CI, 1.25-27.0). Most patients (62.7%) had one or more comorbidities.

CONCLUSIONS

The frequency of ECMO use across the pregnant population was low over this time period, with a mortality rate of 1 in 3 patients. Mortality was greatest in patients with cardiogenic shock. Further work is needed to understand how best to improve ECMO outcomes in pregnant patients.

Breathing variability-implications for anaesthesiology and intensive care

The respiratory system reacts instantaneously to intrinsic and extrinsic inputs. This adaptability results in significant fluctuations in breathing parameters, such as respiratory rate, tidal volume, and inspiratory flow profiles. Breathing variability is influenced by several conditions, including sleep, various pulmonary diseases, hypoxia, and anxiety disorders. Recent studies have suggested that weaning failure during mechanical ventilation may be predicted by low respiratory variability. This review describes methods for quantifying breathing variability, summarises the conditions and comorbidities that affect breathing variability, and discusses the potential implications of breathing variability for anaesthesia and intensive care.