Daily Anesthesiology Research Analysis
Analyzed 102 papers and selected 3 impactful papers.
Summary
Three anesthesia-focused studies stood out today: a randomized trial showed that non-intubated anesthesia for VATS lung surgery halved postoperative pulmonary complications and reduced diaphragmatic dysfunction; a mechanistic study revealed that isoflurane impairs SERCA-dependent calcium removal via mitochondrial complex I inhibition, linking ATP depletion to early neurotoxicity signals; and a randomized trial demonstrated that driving pressure–guided tidal volume titration during one-lung ventilation lowered dependent-lung IL-6, indicating reduced biotrauma.
Research Themes
- Non-intubated anesthesia in thoracic surgery improves pulmonary outcomes
- Mechanistic insights into anesthetic-induced neurotoxicity (calcium handling, mitochondrial ATP)
- Driving pressure–guided ventilation reduces biotrauma during one-lung ventilation
Selected Articles
1. Effect of non-intubated anaesthesia video-assisted thoracoscopic surgery on postoperative diaphragm function and pulmonary complications in patients undergoing lung surgery: a randomized clinical trial.
In a single-center randomized trial of 160 VATS patients, non-intubated anesthesia significantly reduced diaphragmatic dysfunction at 24 hours and halved postoperative pulmonary complications compared with intubated anesthesia. These benefits suggest NIVATS may be a superior option for selected thoracic surgical patients.
Impact: Provides randomized evidence that a non-intubated anesthetic strategy yields clinically meaningful reductions in PPCs and diaphragmatic dysfunction after lung surgery.
Clinical Implications: Consider NIVATS in appropriate VATS candidates to reduce PPCs and preserve diaphragmatic function; implement careful patient selection, surgical/anesthesia team expertise, and conversion readiness.
Key Findings
- PDD at 24 h: 35.0% (NIVATS) vs 57.5% (IVATS); RR 0.61 (95% CI 0.43–0.87); P<0.001
- PPCs within 7 days: 17.5% (NIVATS) vs 33.8% (IVATS); RR 0.52 (95% CI 0.29–0.91); P=0.019
- Randomized 160 VATS patients to NIVATS vs IVATS with ultrasound-defined diaphragm excursion threshold (<10 mm)
Methodological Strengths
- Randomized allocation with prespecified, clinically relevant outcomes (PDD and PPCs)
- Objective diaphragm function assessment by ultrasound and defined PPC follow-up window (7 days)
Limitations
- Single-center design; generalizability may be limited
- Blinding not feasible; selection limited to suitable VATS candidates
Future Directions: Multicenter RCTs with standardized conversion criteria and longer-term outcomes (e.g., readmissions, functional recovery) to define patient selection and implementation frameworks.
BACKGROUND: Postoperative diaphragmatic dysfunction (PDD) and pulmonary complications (PPCs) are common complications in patients undergoing video-assisted thoracoscopic (VATS) lung surgery. There is increasing evidence for the safety and advantages of non-intubated anaesthesia in VATS lung surgery. It remains, however, to be demonstrated whether non-intubated anaesthesia in these patients improved PDD and PPCs. METHODS AND METHODS: Between 9 October 2022 and 26 November 2023, 160 patients scheduled for VATS lung surgery were enrolled and randomly allocated to non-intubated anaesthesia (NIVATS) group or intubated anaesthesia (IVATS) group. The primary outcome was the incidence of PDD at 24 hours postoperatively defined as a diaphragmatic excursion less than 10 mm evaluated by ultrasound. The occurrence of PPCs was assessed up to 7 days after surgery. RESULTS: The incidence of PDD at 24 h was significantly lower in the NIVATS group (28 of 80, [35.0%]) than IVATS group (46 of 80 [57.5%]; relative risk [95% confidence interval], 0.61 [0.43-0.87]; P<0.001). The rate of PPCs was significantly lower in the NIVATS group (14 of 80, [17.5%]) than IVATS group (27 of 80 [33.8%]; relative risk [95% confidence interval], 0.52 [0.29-0.91]; P = 0.019). CONCLUSIONS: Non-intubated anaesthesia reduced the incidence of PDD and PPCs for patients undergoing VATS lung surgery. These findings indicated that NIVATS offers more benefits and may be a superior option compared to IVATS for selected patients.
2. The Effects of Isoflurane Inhibition of Mitochondrial Complex I on Calcium Removal in Mouse Neuronal Cultures.
Isoflurane dramatically prolonged presynaptic calcium decay (t1/2 ~14 s to ~160 s) by impairing ATP-dependent SERCA-mediated calcium removal; ATP supplementation or SERCA activation rescued this defect. Isoflurane also reduced mitochondrial dye uptake and increased cleaved caspase, linking mitochondrial complex I inhibition to early neurotoxicity signaling.
Impact: Clarifies a mechanistic pathway for anesthetic-induced neurotoxicity by pinpointing ATP-dependent SERCA dysfunction as the proximal driver of calcium dysregulation under isoflurane.
Clinical Implications: While preclinical, the findings motivate strategies to preserve mitochondrial ATP or enhance SERCA activity during exposure to volatile anesthetics, and inform risk assessments in vulnerable populations (e.g., developing brain).
Key Findings
- Isoflurane increased presynaptic Ca2+ decay half-life from 14 s (10) to 160 s (77) in wildtype neurons (p=0.001)
- ATP maintenance (30 mM glucose) rescued Ca2+ removal defect (t1/2 ~16 s; p=0.001), and SERCA activation reduced t1/2 to ~36 s (p=0.002)
- Isoflurane decreased MitoView uptake (SERCA-dependent) and increased cleaved caspase, indicating early cellular toxicity
Methodological Strengths
- Use of genetically encoded calcium indicators and targeted pharmacologic modulation (ATP supply, SERCA activation)
- Convergent readouts (Ca kinetics, mitochondrial dye uptake, caspase activation) across wildtype and mutant cultures
Limitations
- In vitro neuronal culture model; in vivo validation is needed
- Anesthetic concentrations and exposure conditions may not fully mirror clinical scenarios
Future Directions: Test mitochondrial-support or SERCA-enhancing interventions in in vivo models and assess neurodevelopmental and functional outcomes under clinically relevant anesthetic exposures.
BACKGROUND: One mechanism proposed for anesthetic-induced neurotoxicity (AIN) is elevated neuronal calcium, leading to mitochondrial damage and caspase activation. Increased cytosolic calcium could arise from increased entry or decreased removal. The relative importances of these distinct mechanisms are unknown. Isoflurane inhibits mitochondrial complex I and reduces ATP at presynaptic terminals leading to synaptic quiescence. We hypothesized that mitochondrial inhibition initiates calcium dysregulation in mouse wildtype and mitochondrial mutant neurons, leading to AIN. METHODS: Presynaptic calcium levels were monitored using VGlut1-GCaMP5 or an ER-specific GCaMP6 during electrical stimulations of neuronal cultures. Cultures were stimulated in the presence of isoflurane and blockers or activators of calcium removal. Mitochondrial damage was monitored using MitoViewTM. Cleaved caspase induction assessed anesthetic-induced neurotoxicity. RESULTS: In the absence of isoflurane, neuronal stimulation transiently increased presynaptic calcium levels. Isoflurane increased the half-life for calcium decay in wildtype cultures (t(sec)) unexposed, 14(10); exposed, 160(77); p =0.001). Maintaining ATP levels rescued the isoflurane-induced defective removal of calcium (t(sec), 30mM glucose, 16(14), n = 8; p = 0.001). Activation of the sarcoplasmic endoplasmic reticulum calcium ATPase (SERCA) alleviated the isoflurane-induced defective removal of calcium (t(sec), no SERCA activator, 159(78); SERCA activator, 36(18); p =0.002). Similar results were seen for mutant cultures exposed to lower, but equipotent, concentrations of isoflurane. Isoflurane induced a SERCA-dependent decrease in uptake of MitoViewTM and an increase in cleaved caspase in wildtype cultures. CONCLUSIONS: Isoflurane causes a failure of SERCA-dependent calcium removal by inhibition of mitochondrial production of ATP. The increase in intracellular calcium leads to early signs of cellular toxicity.
3. Driving Pressure-Guided Tidal Volume Titration Reduces Lung Injury in Thoracic Surgery With One-Lung Ventilation: A Randomized Clinical Trial.
This single-center RCT (n=96) found that driving pressure–guided tidal volume titration targeting 8–10 cm H2O during OLV reduced dependent-lung IL-6 versus a fixed 8 mL/kg PBW strategy. The protocol resulted in lower tidal volumes (~4.6 mL/kg PBW), suggesting reduced biotrauma.
Impact: Provides randomized evidence supporting driving pressure–guided ventilation during OLV to mitigate inflammatory lung injury, aligning with lung-protective principles.
Clinical Implications: Adopting driving pressure–guided tidal volume titration during OLV may reduce intraoperative biotrauma; protocols should incorporate real-time monitoring of driving pressure with careful oxygenation and CO2 targets.
Key Findings
- Driving pressure–guided group achieved tidal volumes ~4.6 mL/kg PBW during OLV (15 and 45 min)
- Dependent-lung IL-6 after OLV was significantly lower with driving pressure guidance (5.31 [3.62]) vs control (7.37 [5.21])
- Targeting driving pressure 8–10 cm H2O was feasible and altered ventilatory dosing compared with fixed 8 mL/kg
Methodological Strengths
- Randomized controlled design with a prespecified physiologic biomarker endpoint (IL-6 in dependent lung)
- Clear ventilatory protocol linking driving pressure targets to delivered tidal volume
Limitations
- Single-center with modest sample size; surrogate endpoint may not translate directly to clinical outcomes
- Details on postoperative clinical endpoints and longer-term outcomes were not primary
Future Directions: Larger multicenter trials powered for clinical outcomes (PPCs, oxygenation trajectories, length of stay) comparing driving pressure–guided vs conventional OLV strategies.
OBJECTIVE: The optimal tidal volume for patients undergoing thoracic surgery with one-lung ventilation (OLV) remains unclear. This study aimed to evaluate whether driving pressure-guided tidal volume titration could reduce lung injury in these patients. DESIGN: Prospective, single-center, randomized controlled trial. SETTING: Single-center academic hospital in China. PARTICIPANTS: A total of 96 patients undergoing thoracic surgery with OLV. INTERVENTIONS: Patients were randomly assigned to either the driving pressure-guided tidal volume group (n = 46) or the control group (n = 50). In the control group, tidal volume was set at 8 mL/kg of predicted body weight (PBW) during OLV. In the driving pressure-guided group, tidal volume was adjusted to maintain a driving pressure between 8 and 10 cm H MEASUREMENTS AND MAIN RESULTS: The primary outcome was the concentration of interleukin 6 (IL-6) in the dependent lung following OLV. The tidal volume in the driving pressure-guided group was 4.65 [4.23-5.65] mL/kg at 15 minutes and 4.58 [4.27-5.41] mL/kg at 45 minutes of OLV. The concentration of IL-6 in the dependent lung after OLV was significantly lower in the driving pressure group (5.31 [3.62]) compared to the control group (7.37 [5.21]) (mean difference: -0.46 [-0.86 to -0.05] cm H CONCLUSIONS: Driving pressure-guided tidal volume titration significantly reduces IL-6 levels in bronchoalveolar lavage fluid from the dependent lung following OLV in patients undergoing thoracic surgery, compared to conventional ventilation using 8 mL/kg PBW.