Daily Anesthesiology Research Analysis
Analyzed 105 papers and selected 3 impactful papers.
Summary
Analyzed 105 papers and selected 3 impactful articles.
Selected Articles
1. Regional Alveolar Damage Despite Lung Protective Ventilation Settings During Robotic-Assisted Laparoscopic Surgery.
Despite lung-protective settings during robotic laparoscopic surgery, the dependent (apical) lung exhibited impaired mechanics with negative end-expiratory transpulmonary pressures and proteomic signatures of alveolar-capillary injury. Increases in BAL total protein and extracellular matrix/coagulation proteins were localized to the dependent region and correlated with dissipated mechanical power, consistent with regional atelectrauma.
Impact: This study provides rare molecular evidence of perioperative atelectrauma localized to dependent lung regions during robotic surgery, directly linking ventilation mechanics to biochemical injury markers.
Clinical Implications: Consider monitoring or targeting end-expiratory transpulmonary pressure and minimizing dissipated mechanical power during steep Trendelenburg to prevent regional injury; individualized higher PEEP, careful recruitment, and driving pressure limitation may be warranted.
Key Findings
- Negative end-expiratory transpulmonary pressures and elevated elastance/driving pressures occurred despite LPV during RALS.
- Dependent (apical) BAL showed increased total protein and ECM/coagulation proteins (fibulin-1, MFAP4, prothrombin, plasminogen; adj. P < .001), not seen in nondependent regions.
- BAL total protein in the dependent region correlated with dissipated mechanical power (r2 = 0.434; P = .014), consistent with regional atelectrauma.
Methodological Strengths
- Paired regional BAL sampling with multi-omics (proteomics, lipidomics) alongside continuous transpulmonary mechanics.
- Within-subject, region-specific comparisons with statistical adjustment for multiple testing.
Limitations
- Small single-center cohort (n=15) without longer-term clinical outcome assessment.
- Observational design limits causal inference; lipidomic changes attenuated after adjustment.
Future Directions: Test individualized PEEP/ventilation strategies guided by transpulmonary pressure and mechanical power to reduce regional injury and evaluate clinical outcomes in larger RALS cohorts.
BACKGROUND: Robotic-assisted laparoscopic surgery (RALS) in a steep Trendelenburg position creates conditions conducive to cyclical alveolar collapse when using standard lung protective ventilation settings (LPV). The magnitude of force induced by alveolar collapse and expansion is predicted to cause a localized injury, but biological evidence of perioperative atelectrauma is lacking. We hypothesized that the negative transpulmonary pressures and increased dissipated power of ventilation encountered during RALS lead to injury of the dependent (apical) lung despite the use of LPV settings. METHODS: We conducted a single-center, observational study of lung mechanics and injury in 15 subjects (8 M/7F; mean ± standard deviation: 59.5 ± 7.4 years) without lung disease undergoing RALS with LPV at an academic hospital in the United States. Subjects had a median body mass index of 32.5 kg/m2 with a range of 24.3 to 50.9 kg/m2. We continuously measured lung mechanics, including transpulmonary pressures. Bronchoalveolar lavages (BAL) were obtained from apical and anteromedial subsegments after intubation and from contralateral subsegments before extubation. During RALS, the apical lung is dependent and the anteromedial lung in nondependent. BAL analyses included total protein concentrations, proteomics, lipidomics, and leukocyte counts. RESULTS: Lung mechanics were impaired, with elevated respiratory elastance and driving pressures, and negative end-expiratory transpulmonary pressures, despite standard LPV settings (tidal volume 7.0 ± 0.8 mL/kg ideal body weight; positive end-expiratory pressure 8.7 ± 3.4 cm H2O). Increases in total protein (median [interquartile range], 131 [27-193] µg/mL), extracellular matrix components (fibulin-1: 2.1 [1.6-4.0] fold; microfibril-associated glycoprotein-4: 2.2 [1.3-4.0] fold), and procoagulants (prothrombin: 1.7 [1.3-4.8] fold; plasminogen: 3.2 [1.9-4.5] fold) were observed in apical BAL after surgery (adj. P < .001 for all), but not in anteromedial BAL (adj. P > .05). No differences in percent leukocyte composition were observed among lavages (P > .287 for all cell types). Phosphatidylglycerol abundance was increased in apical BAL after surgery in unadjusted analyses (5.8 [1.9-7.9] %, P = .021), but no changes in phospholipid abundance were noted in adjusted analysis. Increases in apical BAL total protein were positively correlated with the dissipated mechanical power of ventilation (r2 = 0.434, P = .014). CONCLUSIONS: In this focused biomechanical study, we found molecular evidence for alveolar-capillary damage in the dependent apical lobes, consistent with localized atelectrauma. Regional atelectrauma from impaired lung mechanics can occur in the positionally dependent lung while using LPV settings during RALS, most likely from insufficient end-expiratory pressure.
2. Association between time to target mean arterial pressure and 90-day mortality in septic shock: a post hoc analysis of the OPTPRESS trial.
In a post hoc analysis of the OPTPRESS RCT, reaching the lower-bound MAP target at ≥12 hours (or not at all) was associated with higher 90-day mortality compared with earlier attainment. Continuous modeling within 24 hours showed no per-hour linear association, suggesting delayed attainment is a risk marker but not a strict time threshold.
Impact: The study operationalizes a pragmatic, time-based hemodynamic quality metric linked to long-term mortality in septic shock, informing resuscitation urgency beyond static targets.
Clinical Implications: Early attainment of assigned MAP targets should be prioritized; systems should focus on reducing delays in vasopressor titration and shock control while also measuring hypotension burden to avoid oversimplification.
Key Findings
- Delayed TTT-MAP (≥12 h) versus <1 h was associated with higher 90-day mortality (aOR 1.48; 95% CI 1.11–1.98).
- In Cox models, prolonged TTT-MAP (≥12 h or unreached) increased 90-day mortality risk (aHR 3.24; 95% CI 2.19–4.80).
- Within patients achieving target within 24 h, per-hour TTT-MAP was not significantly associated with mortality (aOR 1.025; p=0.362).
Methodological Strengths
- Use of doubly robust estimation with multiple sensitivity analyses (categorical, continuous, Cox models).
- Randomized trial dataset with prespecified MAP targets enabling causal framing of time-to-attainment.
Limitations
- Post hoc secondary analysis subject to residual confounding; TTT-MAP is not a direct measure of hypotension burden.
- Generalizability may be limited to trial settings and assigned MAP targets (65 vs 80 mmHg).
Future Directions: Prospective protocols to minimize TTT-MAP and quantify hypotension burden concurrently; interventional studies testing workflow changes to expedite MAP target attainment.
BACKGROUND: In septic shock resuscitation, maintaining a mean arterial pressure (MAP) of at least 65 mmHg is recommended; however, the clinical relevance of the time required to achieve target MAP remains unclear. We evaluated the association between time to target MAP (TTT-MAP) and clinical outcomes in septic shock. METHODS: This post hoc secondary analysis used data from the OPTPRESS randomized controlled trial. TTT-MAP was defined as the time from randomization to first attainment of the randomized-arm lower-bound MAP target (80 mmHg in the high-target arm; 65 mmHg in the low-target arm) and categorized as <1 h, 1-3 h, 3-6 h, 6-12 h, ≥12 h, and unreached. The primary outcome was 90-day all-cause mortality. The primary analysis used doubly robust estimation. Secondary analyses included continuous TTT-MAP modeling, Cox proportional hazards models, and assessments of hypotension burden and vasopressor exposure. RESULTS: Among 516 patients enrolled in OPTPRESS, 476 were included in the complete-case cohort. In the primary six-category analysis, compared with TTT-MAP <1 h, the delayed-attainment category (≥12 h) was associated with higher 90-day mortality (adjusted odds ratio [aOR] 1.48, 95% confidence interval [CI] 1.11-1.98; p = 0.008), whereas 1-3 h, 3-6 h, and 6-12 h were not. In the continuous analysis restricted to patients who achieved target MAP within 24 h, TTT-MAP was not significantly associated with 90-day mortality per 1-h increase (aOR 1.025, 95% CI 0.972-1.082; p = 0.362). In Cox models, prolonged TTT-MAP (≥12 h or unreached) was associated with increased 90-day mortality versus early attainment (<12 h and reached) (adjusted hazard ratio [aHR] 3.24, 95% CI 2.19-4.80; p < 0.001). CONCLUSION: In this secondary analysis of the OPTPRESS trial, delayed attainment of the randomized lower-bound MAP target was associated with higher 90-day mortality. However, because TTT-MAP reflects time to first target attainment rather than the hypotension burden itself, these findings should not be interpreted as defining a clinically acceptable duration of hypotension or a threshold effect.
3. Perioperative dexmedetomidine is associated with improved respiratory outcomes in patients undergoing cardiac surgery: a systematic review and meta-analysis of randomized controlled trials.
Across 16 RCTs (n=1,668), perioperative dexmedetomidine was associated with fewer postoperative pulmonary complications (RR 0.57), improved postoperative oxygenation, and slightly shorter ICU stay, though with a higher risk of bradycardia. Evidence quality and PPC definitions varied, warranting larger confirmatory trials.
Impact: Synthesizes randomized evidence suggesting a sedation strategy that may reduce pulmonary morbidity after cardiac surgery—a common and costly complication domain.
Clinical Implications: Consider dexmedetomidine as part of multimodal cardiac anesthesia/sedation when pulmonary risk is high, while monitoring and mitigating bradycardia; protocolized use and dosing remain to be standardized.
Key Findings
- Reduced overall postoperative pulmonary complications with dexmedetomidine (RR 0.57; 95% CI 0.38–0.87).
- Improved postoperative oxygenation (SpO2/PaO2) and a small reduction in ICU length of stay (MD −0.56 h).
- Potential increase in bradycardia events suggests a trade-off requiring careful monitoring.
Methodological Strengths
- Meta-analysis restricted to randomized controlled trials with multiple respiratory endpoints.
- Consistent directionality across studies for PPCs and oxygenation measures.
Limitations
- Heterogeneity in PPC definitions, dosing regimens, and perioperative protocols across trials.
- Bradycardia signal and limited precision for some outcomes necessitate larger, standardized RCTs.
Future Directions: Large, protocolized RCTs to define optimal dosing/timing, confirm PPC reduction, and balance bradycardia risks; subgroup analyses for high-risk phenotypes.
BACKGROUND: Over 2 million cardiac surgeries are performed annually, with significant risks such as systemic inflammation and postoperative pulmonary complications (PPCs). Dexmedetomidine has shown promise in reducing PPCs in thoracic surgeries. This review evaluates its effects on PPCs and respiratory outcomes in cardiac surgery. METHODS: A systematic search of the PubMed, Embase, Cochrane Library, and Web of Science databases was conducted to include randomized controlled trials comparing intravenous dexmedetomidine and other drugs in terms of respiratory outcomes in adult patients undergoing cardiac surgery. PRIMARY OUTCOME: PPC incidence. SECONDARY OUTCOMES: PaO RESULTS: Sixteen studies comprising 1,668 patients were included in this meta-analysis. The perioperative use of dexmedetomidine was associated with a reduced incidence of overall postoperative pulmonary complications (RR = 0.57; 95% CI: 0.38 to 0.87; P = 0.0078). Additionally, participants who received intravenous dexmedetomidine had a shorter ICU stay (MD = -0.56 h; 95% CI: -1.12 to -0.00; P = 0.0480). Furthermore, perioperative dexmedetomidine significantly improved postoperative SpO CONCLUSION: Perioperative dexmedetomidine may be associated with improved respiratory outcomes in cardiac surgery patients. However, the evidence for reduction in overall PPCs remains limited, and dexmedetomidine may increase the risk of bradycardia. Larger, high-quality RCTs are needed to confirm its safety and benefits.