Daily Anesthesiology Research Analysis
Two randomized trials inform perioperative practice: a large RCT shows no outcome difference between restrictive and liberal oxygenation during cardiopulmonary bypass, and a single-center RCT demonstrates that prophylactic nasopharyngeal airways markedly reduce hypoxemia in obese outpatients undergoing painless endoscopy. A national registry analysis reveals substantial morning clustering of anesthesia work, with implications for workforce planning.
Summary
Two randomized trials inform perioperative practice: a large RCT shows no outcome difference between restrictive and liberal oxygenation during cardiopulmonary bypass, and a single-center RCT demonstrates that prophylactic nasopharyngeal airways markedly reduce hypoxemia in obese outpatients undergoing painless endoscopy. A national registry analysis reveals substantial morning clustering of anesthesia work, with implications for workforce planning.
Research Themes
- Perioperative oxygenation strategies during cardiopulmonary bypass
- Airway management to prevent hypoxemia under procedural sedation
- Anesthesiology workforce distribution and operational planning
Selected Articles
1. Restrictive versus liberal oxygenation in patients undergoing cardiopulmonary bypass-assisted heart surgery: a randomised controlled trial.
In a single-center, patient- and assessor-blinded RCT of 1,389 adults undergoing CPB-assisted CABG and/or AVR, restrictive versus liberal oxygenation during CPB and weaning produced no significant differences in mortality, dialysis-dependent renal failure, stroke, or heart failure. Findings suggest no clinical advantage to restricting oxygen compared with a liberal approach in this context.
Impact: This high-quality randomized trial directly informs a common intraoperative management question and challenges assumptions that oxygen restriction improves outcomes during CPB.
Clinical Implications: Routine restrictive oxygen targets during CPB are unlikely to confer benefit on major outcomes; clinicians can prioritize ensuring adequate oxygenation without aggressive restriction, while monitoring for hyperoxia-related risks.
Key Findings
- No significant differences in mortality, dialysis-dependent renal failure, stroke, or heart failure between restrictive and liberal oxygenation strategies.
- Randomized, patient- and assessor-blinded design with 1,389 participants enhances internal validity.
- Trial was prospectively registered (NCT02673931).
Methodological Strengths
- Randomized, patient- and assessor-blinded trial design
- Large sample size with prespecified clinical endpoints and trial registration
Limitations
- Single-center study may limit generalizability across diverse CPB practices
- Potential limited power to detect small differences in rare outcomes
Future Directions: Multicenter trials comparing specific oxygen targets with organ injury biomarkers and neurocognitive outcomes could refine oxygenation strategies during and after CPB.
BACKGROUND: Maintaining adequate oxygen delivery during cardiopulmonary bypass (CPB)-assisted cardiac surgery is crucial, but hyperoxia has been suggested to cause organ injury. We compared the effects of restrictive vs liberal oxygenation during CPB and weaning from CPB on clinical outcomes in cardiac surgery. METHODS: We conducted a single-centre, patient- and assessor-blinded randomised trial on adults undergoing CPB-assisted coronary artery bypass grafting, aortic valve replacement, or both. Participants were randomly assigned (1:1) to restrictive (Fio RESULTS: Among 1389 participants (mean age, 67 yr [range, 29-85 yr]; 17% female), randomisation to receive Fio CONCLUSIONS: Among patients undergoing elective or urgent CPB-assisted coronary artery bypass grafting, aortic valve replacement, or both, no significant differences were observed in mortality, dialysis-dependent renal failure, stroke, or new-onset or worsening heart failure between a restrictive oxygenation strategy (Fio CLINICAL TRIAL REGISTRATION: NCT02673931.
2. Nasopharyngeal airway relieves upper airway obstruction to alleviate hypoxemia during painless gastrointestinal endoscopy for obese outpatients: a prospective randomized controlled trial.
In obese outpatients undergoing painless gastrointestinal endoscopy, prophylactic nasopharyngeal airway placement reduced hypoxemia from 37.2% to 2.3% without destabilizing vital signs and improved clinician satisfaction. The device was rapidly placed and well tolerated.
Impact: The large effect size in a randomized trial supports a simple, low-cost intervention to prevent peri-procedural hypoxemia in a high-risk population.
Clinical Implications: Consider routine prophylactic nasopharyngeal airway placement for obese outpatients undergoing painless endoscopy under sedation to mitigate hypoxemia, alongside standard monitoring and oxygen supplementation.
Key Findings
- Hypoxemia incidence was 2.27% with nasopharyngeal airway versus 37.21% in controls (P<0.001).
- No significant differences in vital signs at intubation or extubation; higher satisfaction scores among endoscopists and anesthesiologists with the device.
- Device placement was rapid (most within 5–10 seconds) and well tolerated (VAS ≤3 for all).
Methodological Strengths
- Prospective randomized controlled design with clear primary endpoint
- Large effect size with clinically meaningful and easily implementable intervention
Limitations
- Single-center study limits generalizability
- Blinding not feasible, introducing potential performance bias; outcomes limited to periprocedural period
Future Directions: Multicenter trials comparing prophylactic airway strategies (nasal cannula with reservoir, high-flow nasal oxygen, oral/nasopharyngeal airways) across BMI strata and sedation regimens are warranted.
PURPOSES: To investigate the efficacy of nasopharyngeal airway intubation in alleviating hypoxemia in obese outpatients undergoing painless gastrointestinal endoscopy. METHODS: This prospective single-center randomized controlled trial was conducted at the Deyang People's Hospital, Deyang, China. Obese outpatients scheduled for painless gastrointestinal endoscopy were randomly assigned to either the nasopharyngeal airway (Group N) or control group (Group C). Nasopharyngeal airway intubation was performed prior to the examination. The primary outcome was the incidence of hypoxemia, while secondary outcomes included intubation duration, procedural interruptions due to desaturation, security events, visual analog scale (VAS) scores, satisfaction scores, and device placement metrics. RESULTS: A total of 88 patients in Group N and 86 patients in Group C were analyzed. The incidence of hypoxemia was 2.27 % in Group N compared to 37.21 % in Group C (P < 0.001). Post-endoscopy, pulse oxygen saturation in Group C was significantly lower than in Group N (P = 0.001). Vital signs showed no differences at the time of intubation and extubation (P > 0.05). Satisfaction scores for endoscopists and anesthesiologists were higher in Group N than in Group C, with scores of 9.97 ± 0.18 vs. 9.73 ± 0.82 (P = 0.01) and 9.89 ± 0.47 vs. 9.10 ± 1.15 (P < 0.001), respectively. In Group N, 87 patients received nasopharyngeal airway intubation, with 69 intubations completed within 5 s, 18 within 10 s, and one patient requiring two attempts within 15 s. In Group N, the VAS score for all patients was ≤3. CONCLUSIONS: Prophylactic nasopharyngeal airway intubation effectively alleviates hypoxemia in obese outpatients undergoing painless gastrointestinal endoscopy without increasing side effects. This cost-effective intervention offers a superior strategy for managing hypoxemia in this patient population.
3. United States' anesthesia workdays in 2022-2023 - Implications for national workforce assessments.
Analysis of 13.9 million anesthetics (2022–2023 NACOR) shows strong weekday morning clustering: 82.9% of regular workday anesthesia minutes fall between 7:30 and 15:29, with 61.2% completed before 13:00 (up from 53.0% in 2013). These patterns likely amplify perceived workforce shortages and support development of acute care anesthesiology teams.
Impact: This national, contemporary quantification of anesthesia workload distribution provides actionable evidence for staffing models and scheduling, addressing a key systems-level driver of workforce strain.
Clinical Implications: Hospitals should align staffing with pronounced morning peaks, consider flexible shift designs, and evaluate acute care anesthesiology teams for weekend coverage to mitigate bottlenecks and perceived shortages.
Key Findings
- Regular workdays accounted for 95.5% of total anesthesia minutes.
- On regular workdays, 82.9% of anesthesia minutes occurred between 07:30–15:29; 61.2% were completed before 13:00, up from 53.0% in 2013.
- Weekends showed smaller but significant changes, supporting development of acute care anesthesiology teams.
Methodological Strengths
- Extremely large, contemporary national dataset (N=13,901,414) with standardized time-stamp methodology
- Direct comparability to prior 2013 analysis enabling temporal trend assessment
Limitations
- Observational registry study subject to coding errors and selection biases; excludes labor epidurals
- Findings describe workload distribution; no causal inference on outcomes or productivity
Future Directions: Operations research using these distributions to simulate staffing models, evaluate staggered starts, and quantify effects on delays, overtime, and burnout is warranted.
BACKGROUND: Over the decade from 2013 to 2023, the percentage increase in the number of anesthesia clinicians in the United States increased more than the percentage increase in the yearly number of cases involving an anesthesia clinician. A potential explanation is that the expansion of ambulatory surgery has increased anesthetizing locations on weekday mornings, thereby decreasing overall anesthetic hours per clinician. We tested this hypothesis using 2022-2023 data from the American Society of Anesthesiologist's National Anesthesia Clinical Outcomes Registry. We performed analyses comparable to those from our earlier studies using 2013 NACOR data. METHODS: We studied N = 13,901,414 anesthetics, excluding labor epidurals. Cases' start and end dates and times were used to create categories, including regular workdays (Mondays - Fridays, excluding US federal holidays) and weekends (Saturdays - Sundays). Proportions of cases were estimated along with standard errors calculated among the 26 four-week periods. A similarity index compared pairwise, between regular workdays and weekends, the relative proportions of different anesthesia Current Procedural Terminology procedure codes. RESULTS: Regular workdays accounted for 95.5 % of the total anesthetic minutes. Among regular workdays, the 8-h period of 7:30 AM to 3:29 PM had 82.9 % (0.1 %) of anesthesia minutes, significantly >0.8 (i.e., ⅘, P < .0001). There were 61.2 % (0.1 %) of all anesthetic minutes completed on regular workdays and before 1:00 PM, significantly >53.0 % (P < .0001), the percentage from 2013. There were 79.2 % (0.1 %) of all anesthetic minutes on regular workdays 7:30 AM to 3:29 PM, significantly >70.3 % (P < .0001), from 2013. At least ⅔ CONCLUSIONS: Nationwide, anesthesia times on regular workdays sum to substantially less than 8 h and even less than in 2013. Demand for daily numbers of clinicians at the start of the regular workdays probably is a large contributor to perceived workforce shortages and ongoing institutional support. The small but significant changes for weekends suggest an increased rationale for the development of acute care anesthesiology teams.