Daily Anesthesiology Research Analysis
Three studies stand out in anesthesiology and perioperative care. A network meta-analysis of 74 RCTs shows prophylactic continuous infusion of norepinephrine or phenylephrine best prevents spinal anesthesia-induced hypotension and intraoperative nausea/vomiting during cesarean delivery without harming neonatal outcomes. In ECPR, a ≥4% SpO2–SaO2 discrepancy at 24 hours independently predicts mortality, underscoring the need for arterial validation of oximetry. A meta-analysis supports erector spi
Summary
Three studies stand out in anesthesiology and perioperative care. A network meta-analysis of 74 RCTs shows prophylactic continuous infusion of norepinephrine or phenylephrine best prevents spinal anesthesia-induced hypotension and intraoperative nausea/vomiting during cesarean delivery without harming neonatal outcomes. In ECPR, a ≥4% SpO2–SaO2 discrepancy at 24 hours independently predicts mortality, underscoring the need for arterial validation of oximetry. A meta-analysis supports erector spinae plane block after cardiac surgery to reduce opioid use and late-phase pain, with modest effects on ventilation duration.
Research Themes
- Vasopressor strategy for spinal anesthesia-induced hypotension in cesarean delivery
- Accuracy and prognostic value of oxygenation monitoring in ECPR
- Regional anesthesia to optimize analgesia after cardiac surgery
Selected Articles
1. Norepinephrine vs. phenylephrine for spinal hypotension in cesarean section: a network meta-analysis.
Across 74 RCTs (n=7,798), prophylactic continuous infusion of norepinephrine or phenylephrine reduced spinal anesthesia-related hypotension and intraoperative nausea/vomiting compared with phenylephrine bolus, without compromising neonatal outcomes. Adverse event profiles differed (more bradycardia with phenylephrine; more hypertension with infusions), but efficacy was similar between norepinephrine and phenylephrine infusions.
Impact: This synthesis provides high-level evidence to standardize vasopressor strategy for cesarean spinal anesthesia, favoring prophylactic infusion over bolus dosing. It can immediately inform protocols, education, and quality improvement in obstetric anesthesia.
Clinical Implications: Adopt prophylactic continuous infusion of either norepinephrine or phenylephrine during cesarean spinal anesthesia to reduce hypotension and IONV; choose agent considering maternal heart rate (phenylephrine more bradycardia-prone) and institutional familiarity. Routine neonatal outcomes appear unaffected.
Key Findings
- Prophylactic infusion of norepinephrine or phenylephrine reduced IONV versus phenylephrine bolus (RR 0.47 and 0.54, respectively).
- Prophylactic infusion significantly decreased postspinal hypotension (NE RR 0.25; PE RR 0.29).
- Apgar scores and umbilical artery pH were similar across strategies.
- Adverse events differed by regimen: more bradycardia with phenylephrine, more hypertension with infusions; bolus strategies showed more tachycardia.
Methodological Strengths
- Large network meta-analysis including 74 RCTs with 7,798 participants
- Use of random-effects models and CINeMA for confidence assessment
Limitations
- Heterogeneity in dosing regimens, infusion targets, and prophylactic vs therapeutic use
- Adverse event reporting and definitions varied across trials
Future Directions: Head-to-head RCTs comparing fixed vs titrated infusion targets and norepinephrine vs phenylephrine in high-risk subgroups; standardized adverse event definitions and maternal satisfaction outcomes.
PURPOSE: Postspinal hypotension (PSH) during cesarean section (CS) often causes maternal intraoperative nausea and vomiting (IONV) and fetal acidosis. Phenylephrine (PE) and norepinephrine (NE) are commonly used for management; however, the optimal agent and method (bolus vs. infusion) remains uncertain. This review assessed bolus and infusion of PE and NE for IONV and PSH during CS. METHODS: Systematic searches of MEDLINE, Embase, CENTRAL, and unpublished studies identified randomized controlled trials (RCTs) on PE and NE administration during CS under spinal anesthesia. Primary outcomes included IONV and PSH, whereas secondary outcomes encompassed Apgar scores, umbilical artery pH, rescue vasopressor bolus requirements, and adverse events. A random-effects meta-analysis and the Confidence in Network Meta-Analysis tool were utilized. RESULTS: Among 74 RCTs (7798 patients), NE and PE infusion reduced IONV compared with PE bolus (risk ratio [RR]: 0.47; 95% confidence interval [CI] 0.34-0.66; RR: 0.54; 95% CI 0.42-0.69, high confidence). Similarly, these approaches reduced PSH (NE infusion: RR: 0.25; 95% CI 0.21-0.31, high confidence; PE infusion: RR: 0.29; 95% CI 0.24-0.34, moderate confidence). Rescue vasopressor bolus requirements showed a similar trend. Apgar scores and umbilical artery pH were comparable across all groups. Adverse event varied, with bradycardia more common with PE, tachycardia with boluses, and dizziness with PE bolus. Hypertension was more frequent with infusions. In prophylactic studies, hypotension trends persisted, but no differences were observed in IONV. CONCLUSION: Prophylactic continuous infusion appears to be a favorable strategy for managing PSH and IONV during CS. No significant difference was observed between PE and NE infusions in preventing PSH and IONV.
2. Pulse Oximetry and Arterial Blood Gas Oxygen Saturation Discrepancies and Mortality in Extracorporeal Cardiopulmonary Resuscitation Patients: An Extracorporeal Life Support Organization Registry Analysis.
In a multicenter ELSO registry analysis of 3,970 adults on ECPR, an SpO2–SaO2 discrepancy ≥4% at 24 hours was independently associated with higher in-hospital mortality (aOR 1.39). The signal was consistent across races/ethnicities and accompanied by higher lactate. Acute brain injury and extreme hyperoxemia/ hypoxemia were additional strong predictors.
Impact: Defines a pragmatic threshold for oximetry-arterial saturation discrepancy that correlates with mortality, prompting protocolized ABG validation and reassessment of monitoring strategies in ECPR.
Clinical Implications: In ECPR, do not rely solely on SpO2; obtain arterial co-oximetry when SpO2–SaO2 gap approaches or exceeds 4%, optimize probe placement/perfusion, and reassess oxygen targets to avoid unrecognized hypoxemia and harmful hyperoxemia.
Key Findings
- At 24 hours, SpO2–SaO2 ≥4% occurred in 16% and was linked to higher mortality (67% vs 59%; adjusted OR 1.39).
- Higher lactate, acute brain injury, hyperoxemia (PaO2 ≥200 mmHg) and hypoxemia (PaO2 <60 mmHg) independently predicted mortality.
- Association between saturation discrepancy and mortality did not differ by race/ethnicity.
Methodological Strengths
- Large multicenter registry with 3,970 ECPR patients from 496 centers
- Predefined threshold via spline analysis and multivariable adjustment for key confounders
Limitations
- Observational design with potential residual confounding and measurement variability across centers
- Single time-point (24h) assessment; device and perfusion factors could affect SpO2 accuracy
Future Directions: Prospective studies to test protocols using ABG-guided oxygenation targets when SpO2–SaO2 gap ≥4%; evaluate interventions to minimize discrepancy (probe site, perfusion optimization, signal quality).
OBJECTIVES: Previous studies have shown that inaccurate peripheral oxygen saturation (Sp o2 ) readings compared with arterial oxygen saturation (Sa o2 ) may occur in extracorporeal membrane oxygenation (ECMO) patients. We hypothesized that a greater Sp o2 -Sa o2 discrepancy in extracorporeal cardiopulmonary resuscitation (ECPR) patients is associated with higher mortality due to unrecognized hypoxemia. DESIGN: Retrospective analysis. SETTING: Data within the Extracorporeal Life Support Organization Registry from 496 ECMO centers (2018-2024). PATIENTS: Patients 18 years old or older receiving ECPR (first-run only). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Laboratory measurements including Sp o2 -Sa o2 were measured at 24 hours of ECMO support. Acute brain injury (ABI) included hypoxic-ischemic brain injury, ischemic stroke, intracranial hemorrhage, and seizures. Based on an inflection point in cubic spline analysis, a Sp o2 -Sa o2 threshold greater than or equal to 4% was used as a binary variable to assess its association with in-hospital mortality. Three thousand nine hundred seventy ECPR patients (median age, 57 yr; 71% male) were included. The median ECMO duration was 4 days (interquartile range, 2-7 d). There were 634 patients (16%) with Sp o2 -Sa o2 greater than or equal to 4% and 3336 (84%) with Sp o2 -Sa o2 less than 4%. Overall mortality was 60% ( n = 2391). Patients with Sp o2 -Sa o2 greater than or equal to 4% had higher mortality compared with patients with Sp o2 -Sa o2 less than 4% (67%, n = 425 vs. 59%, n = 1966; p < 0.001). Patients with Sp o2 -Sa o2 greater than or equal to 4% had higher serum lactate values than those with Sp o2 -Sa o2 less than 4% (3.1 vs. 2.8 mmol/L; p = 0.0017). In multivariable logistic regression adjusted for preselected covariates, Sp o2 -Sa o2 greater than or equal to 4% was associated with increased risk of mortality (adjusted odds ratio [aOR], 1.39; 95% CI, 1.13-1.71). Additional risk factors associated with higher mortality included ABI (aOR, 5.81; 95% CI, 4.70-7.20), hyperoxemia greater than or equal to 300 mm Hg (aOR, 1.93; 95% CI, 1.53-2.43), hyperoxemia 200-299 mm Hg (aOR, 1.76; 95% CI, 1.37-2.25), gastrointestinal hemorrhage (aOR, 1.69; 95% CI, 1.42-2.00), renal replacement therapy (aOR, 1.48; 95% CI, 1.03-2.11), hypoxemia less than 60 mm Hg (aOR, 1.45; 95% CI, 1.00-2.10), older age (aOR, 1.19; 95% CI, 1.13-1.26), and higher lactate (aOR, 1.17; 95% CI, 1.13-1.20). Race/ethnicity was not associated with higher mortality. CONCLUSIONS: Sp o2 -Sa o2 greater than or equal to 4% in the first 24 hours after ECPR is associated with increased risk of mortality, potentially due to unrecognized hypoxemia, irrespective of race/ethnicity.
3. Meta-analysis of erector spinae plane block efficacy in managing postoperative pain following cardiac surgery.
Across 23 RCTs after adult cardiac surgery, ESPB reduced opioid consumption and improved pain at 48–72 hours, with a modest reduction in ventilation time and no effect on ICU/hospital stay. Technique heterogeneity and moderate-to-low certainty highlight the need for standardized approaches and confirmatory trials.
Impact: Supports incorporating ESPB into multimodal analgesia pathways for cardiac surgery to reduce opioid exposure and late-phase pain, with signals toward enhanced recovery.
Clinical Implications: Consider ESPB as part of ERAS protocols for cardiac surgery to reduce opioid use and day 2–3 pain. Standardize block level, volume, timing, and consider continuous catheter vs single-shot based on resources and patient needs.
Key Findings
- No significant difference in 24-hour cough pain, but significant reductions at 48 h and 72 h (MD −0.60 and −0.67).
- 24-hour morphine consumption decreased (MD −2.04) and mechanical ventilation duration shortened by ~26.5 minutes.
- No differences in ICU or hospital length of stay; substantial heterogeneity and variable ESPB techniques.
Methodological Strengths
- Focus on randomized controlled trials in a single surgical domain
- Comprehensive assessment of pain, opioid consumption, and ventilation metrics
Limitations
- High heterogeneity (I² >50%) and moderate-to-low GRADE certainty
- Variability in ESPB techniques (level, volume, single-shot vs continuous) and co-analgesics
Future Directions: Standardized, adequately powered RCTs comparing continuous vs single-shot ESPB with uniform protocols; incorporate functional recovery, pulmonary complications, and patient-reported outcomes.
Cardiac surgery is associated with significant postoperative pain, necessitating effective multimodal analgesia to reduce opioid-related morbidity. This systematic review and meta-analysis evaluated the analgesic efficacy of erector spinae plane block (ESPB) in adult cardiac surgery. Twenty-three randomized controlled trials (1,612 patients) were included. Primary outcomes revealed no significant difference in 24-hour postoperative coughing pain scores between ESPB and control groups (MD 0.12; 95 % CI:0.26 to 0.50; P = 0.54). However, ESPB demonstrated significant reductions in coughing and resting pain scores at 48 h (MD -0.60; 95 % CI:0.81to-0.38; P < 0.00001) and 72 h (MD -0.67; 95 % CI:1.02 to-0.33; P = 0.0001), alongside reduced 24-hour morphine consumption (MD -2.04; 95 % CI:2.46 to-1.61; P < 0.00001) and shorter mechanical ventilation duration (MD -26.53 minutes; 95 % CI:41.78 to-11.27; P = 0.0007). No differences were observed in ICU/hospital stays or surgical/anesthesia durations. Subgroup analyses highlighted variability in continuous versus single-shot ESPB techniques. High heterogeneity (I² >50 %) and moderate-to-low GRADE evidence underline the need for standardized protocols. ESPB shows promise in enhancing recovery by reducing opioid use and late-phase pain, though further high-quality trials are warranted.