Anaesthesia Critical Care & Pain Medicine最新文献

Discussions of the environmental impacts of general anesthetics have focused on greenhouse gas (GHG) emissions from inhaled agents, with those of total intravenous anesthesia (TIVA) recently coming to the forefront. Clinical experts are calling for the expansion of research toward life cycle assessment (LCA) to comprehensively study the impact of general anesthetics. We provide an overview of proposed environmental risks, including direct GHG emissions from inhaled anesthetics and non-GHG impacts and indirect GHG emissions from propofol. A practical description of LCA methodology is also provided, as well as how it applies to the study of general anesthesia. We describe available LCA studies comparing the environmental impacts of a lower carbon footprint inhaled anesthetic, sevoflurane, to TIVA/propofol and discuss their life cycle steps: manufacturing, transport, clinical use, and disposal. Significant hotspots of GHG emission were identified as the manufacturing and disposal of sevoflurane and use (attributed to the manufacture of the required syringes and syringe pumps) for propofol. However, the focus of these studies was solely on GHG emissions, excluding other environmental impacts of wasted propofol, such as water/soil toxicity. Other LCA gaps included a lack of comprehensive GHG emission estimates related to the manufacturing of TIVA plastic components, high-temperature incineration of propofol, and gas capture technologies for inhaled anesthetics. Considering that scarce LCA evidence does not allow for a definite conclusion to be drawn regarding the overall environmental impacts of sevoflurane and TIVA, we conclude that current anesthetic practice involving these agents should focus on patient needs and established best practices as more LCA research is accumulated.

Background

Adenotonsillectomy is often curative for pediatric obstructive sleep apnea, yet children remain at high risk of respiratory complications in the postoperative period. We sought to determine the incidence and risk factors for respiratory depression and airway obstruction, as well as clinically apparent respiratory events in the post-anesthesia care unit (PACU) in high-risk children after adenotonsillectomy.

Methods

In this prospective cohort study, we enrolled 60 high-risk children having adenotonsillectomy. Our primary outcome was respiratory depression and airway obstruction in the PACU measured using a noninvasive respiratory volume monitor (RVM) and defined by episodes of predicted minute ventilation less than 40% for at least 2 min. We measured clinically apparent respiratory events using continuous observation by trained study staff.

Results

The median (range) age of our sample was 4 years (1, 16) and 27 (45%) were female. Black and Hispanic race children comprised 80% (n = 48) of our cohort. Thirty-nine (65%) had at least one episode of PACU respiratory depression or airway obstruction measured using the RVM, while only 21 (35%) had clinically apparent respiratory events. Poisson regression demonstrated the following associations with an increase in episodes of respiratory depression and airway obstruction: BMI Z-score less than −1 (estimate 3.91; [95%CI 1.49–10.23]), BMI Z-score 1–2 (estimate 2.04; [1.20–3.48]), and two or more comorbidities (estimate 1.96; [1.11–3.46]).

Conclusions

Respiratory volume monitoring in the immediate postoperative period after pediatric high-risk adenotonsillectomy identifies impaired ventilation more frequently than is clinically apparent.

Background

Whether the optimization of cerebral oxygenation based on regional cerebral oxygen saturation (rSO₂) monitoring reduces the occurrence of cerebral ischemic lesions is unknown.

Methods

This multicenter, randomized, controlled trial recruited adults admitted for scheduled carotid endarterectomy. Patients were randomized between the standard of care or optimization of cerebral oxygenation based on rSO₂ monitoring using near-infrared spectroscopy. In the intervention group, in case of a decrease in rSO₂ in the intervention, the following treatments were sequentially recommended: (1) increasing oxygenotherapy, (2) reducing the tidal volume, (3) legs up-raising, (4) performing a fluid challenge and (5) initiating vasopressor support. The primary endpoint was the number of new cerebral ischemic lesions detected using magnetic resonance imaging pre- and postoperatively. Secondary endpoints included new neurological deficits and mortality on day 120 after surgery.

Results

Among the 879 patients who were randomized, 665 (75.7%) were men. There was no statistically significant difference between groups for the mean number of new cerebral ischemic lesions per patient up to 3 days after surgery: 0.35 (±1.05) in the standard group vs. 0.58 (±2.83), in the NIRS group; mean difference, 0.23 [95% CI, −0.06 to 0.52]; estimate, 0.22 [95% CI, −0.06 to 0.50]. New neurological deficits up to day 120 after hospital discharge were not different between the groups: 15 (3,39%) in the standard group vs. 42 (5,49%) in the NIRS group; absolute difference, 2,10 [95% CI, −0,62 to 4,82]. There was no significant difference between groups for the median [IQR] hospital length of stay: 4.0 [4.0–6.0] in the standard group vs. 5.0 [4.0–6.0] in the NIRS group; mean difference, −0.11 [95% CI, −0.65 to 0.44]. The mortality rate on day 120 was not different between the standard group (0.68%) vs. the NIRS group (0.92%); absolute difference = 0.24% [95% CI, −0.94 to 1.41].

Conclusions

Among patients undergoing carotid endarterectomy, optimization of cerebral oxygenation based on rSO₂ did not reduce the occurrence of cerebral ischemic lesions postoperatively compared with controlled hypertensive therapy.

Trial registration

ClinicalTrials.gov identifier: NCT01415648.

Background

To date, there is no instrument to adequately assess self-reported quality of recovery (QoR) in the post-anesthesia care unit (PACU). We previously developed the QoR-PACU, a 13-item questionnaire specifically applicable to the PACU. The feasibility, acceptance, and validity of the QoR-PACU were promising. However, measures of reliability were slightly lower than expected.

Methods

We modified the QoR-PACU and evaluated its psychometric properties in a cohort of adult patients scheduled for non-cardiac surgery with general anesthesia. The modified QoR-PACU (termed QoR-PACU₂) was administered before surgery and postoperatively in the PACU at the time of the decision to discharge.

Results

A total of 307 patients were included in the final analysis. Postoperative QoR-PACU₂ sum scores differed across categories of sex, perioperative and surgical risk, and modes of airway management. The duration of anesthesia and surgery, maximum pain intensity and analgesic requirement in the PACU, and length of PACU stay were all inversely correlated with QoR in the PACU. Cronbach’s alpha was 0.70 (95%CI: 0.66–0.75). The intra-class correlation coefficient was 0.86 (95%CI: 0.70–0.94, p < 0.001) for intra-rater reliability (n = 24) and 0.94 (95%CI 0.90 to 0.97, p < 0.001) for inter-rater reliability (n = 31). Cohen’s effect size was 0.68 and the standardized response mean was 0.57.

Conclusion

The QoR-PACU₂ assesses self-reported QoR after surgery in the PACU. Measures of feasibility, validity, and reliability were consistently high. Measures of responsiveness were moderate, which might be attributable to the heterogeneity of the study population. Future studies should include aspects of ethnicity and cross-cultural applicability.

Background

This study describes the population pharmacokinetics of cefoxitin in obese patients undergoing elective bariatric surgery and evaluates different dosing regimens for achievement of pre-defined target exposures.

Methods

Serial blood samples were collected during surgery with relevant clinical data. Total serum cefoxitin concentrations were measured by chromatographic assay and analysed using a population PK approach with Pmetrics®. The cefoxitin unbound fraction (fu) was estimated. Dosing simulations were performed to ascertain the probability of target attainment (PTA) to achieve cefoxitin fu above minimum inhibitory concentrations (MIC) from surgical incision to wound closure. Fractional target attainment (FTA) was calculated against MIC distributions of common pathogens.

Results

A total of 123 obese patients (median BMI 44.3 kg/m²) were included with 381 cefoxitin concentration values. Cefoxitin was best described by a one-compartment model, with a mean clearance and volume of distribution of 10.9 ± 6.1 L/h and 23.4 ± 10.5 L, respectively. In surgery <2 h, a 2 and a 4 g doses were sufficient for an MIC up to 4 and 8 mg/L (fu 50%), respectively. In prolonged surgery (2–4 h), only continuous infusion enabled optimal PTA for an MIC up to 16 mg/L. Optimal FTAs were obtained against Staphylococcus aureus and Escherichia Coli only when simulating with 50% cefoxitin protein binding (intermittent regimen) and regardless of the protein binding for the continuous infusion.

Conclusion

Intermittent dosing regimens resulted in optimal FTAs against susceptible MIC distributions of S. aureus and E. coli when simulating with 50% cefoxitin protein binding. Continuous infusion of cefoxitin may improve FTA regardless of protein binding.

Study registration

Registration on ClinicalTrials.gov, NCT03306290

Background

Remimazolam is a safe and effective new benzodiazepine sedative that has unique advantages in anesthesia induction and maintenance. The differences in the electroencephalogram bispectral index (BIS) during general anesthesia between propofol and remimazolam deserve further exploration.

Methods

Single-center randomized crossover study. Patients who required multiple hysteroscopic surgery were randomly assigned to use remimazolam (0.27 mg/kg for induction and 1 mg/kg/h for maintenance) first and then propofol (2.0 mg/kg for induction and 6 mg/kg/h for maintenance) during hysteroscopic surgery again 3 months later, or in the opposite order. Both drugs were used at the latest ED₉₅ for unconsciousness. The BIS values (primary endpoint), intraoperative conditions, and incidence of adverse reactions (secondary endpoints) were compared at each time point. BIS values were analyzed with a mixed model of repeated measurements (MMRM).

Results

Seventeen patients completed the study. The lowest BIS value in the remimazolam regimen was significantly higher than that in the propofol regimen (p = 0.001). The MMRM analysis of the BIS values revealed significant differences between the regimens at each time point (p < 0.001). The intraoperative diastolic blood pressure and heart rate changes were smaller, the recovery was faster, and there were fewer adverse reactions and less injection pain, but a greater incidence of intraoperative body movement and hiccups, in the remimazolam regimen.

Conclusion

The trial indicated that remimazolam maintained a higher BIS level than propofol. The correlation between the BIS and the depth of anesthesia induced by remimazolam needs to be further studied.

Trial registration

This trial is registered at ClinicalTrials.gov: ChiCTR2200064551