Sustained Mood Improvement with Laughing Gas Exposure (SMILE): Study protocol for a randomized placebo-controlled pilot trial of nitrous oxide for treatment-resistant depression

BACKGROUND

Nitrous oxide has shown potentially as an efficacious intervention for treatment-resistant depression, yet there remains insufficient evidence pertaining to repeated administration of nitrous oxide over time and active placebo-controlled studies with optimal blinding. Thus, we aim to examine the feasibility and preliminary efficacy of a six-week follow up study examining the effects of a 4 week course of weekly administered nitrous oxide as compared to the active placebo, midazolam.

METHODS

In this randomized, active placebo-controlled, pilot trial, 40 participants with treatment-resistant depression will receive either inhaled nitrous oxide (1 hour at 50% concentration) plus intravenous saline (100mL) or inhaled oxygen (1 hour at 50% concentration) plus intravenous midazolam (0.02 mg/kg in 100mL, up to 2mg) once per week, for 4 consecutive weeks. Participants will be followed up for 6 weeks starting from the first treatment visit. Primary feasibility outcomes include recruitment rate, withdrawal rate, adherence, missing data, and adverse events. The primary exploratory clinical outcome is change in Montgomery-Åsberg Depression Rating Scale (MADRS) score at day 42 of the study. Other exploratory clinical outcomes include remission (defined as MADRS score <10), response (defined as ≥ 50% reduction in MADRS score), and adverse side effects.

DISCUSSION

This pilot study will provide valuable information regarding the feasibility and preliminary efficacy of repeated nitrous oxide administration over time for treatment-resistant depression. If feasible, this study will inform the design of a future definitive trial of nitrous oxide as an efficacious and fast-acting treatment for treatment-resistant depression.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04957368. Registered on July 12, 2021.

A hood shield reduces postdoffing contamination during simulated COVID-19 airway management: an exploratory, simulation-based randomized study

PURPOSE

SARS-CoV-2 poses a significant occupational health threat to health care workers performing aerosol-generating medical procedures, with a threefold increased risk of a positive test and predicted infection compared with the general population. Nevertheless, the personal protective equipment (PPE) configuration that provides better protection with lower contamination rates is still unknown.

METHODS

We enrolled 40 practitioners with airway management training (anesthesiologists, anesthesia assistants/nurses) in an exploratory, simulation-based randomized study. We evaluated the performance of a novel, locally designed hood (n = 20) in terms of protection from surrogate contamination using an ultraviolet (UV) marker during a standardized urgent intubation procedure and a simulated episode of coughing in a high-fidelity simulation setting compared with standard PPE (n = 20). The primary outcome was the presence of residual UV fluorescent contamination on any base clothing or exposed skin of the upper body after doffing PPE assessed by a blinded evaluator.

RESULTS

The proportion of participants with residual contamination on any base clothing or exposed skin of the upper body after doffing was less than half in the hood PPE group compared with the standard PPE group (8/20 [40%] vs 18/20 [90%], respectively; P = 0.002).

CONCLUSIONS

Compared with standard PPE, enhanced PPE with a locally designed prototype hood was associated with reduced contamination of the upper torso and fewer body areas being exposed to droplets after a simulated aerosol-generating scenario without designed airflow.

STUDY REGISTRATION

ClinicalTrials.gov (NCT04373096); registered 4 May 2020.

Anesthetic management of patients with class 3 obesity undergoing elective Cesarean delivery: a single-centre historical cohort study

PURPOSE

The preferred neuraxial anesthetic technique for patients with class 3 obesity undergoing elective Cesarean delivery is still under debate. We aimed to describe the anesthetic technique used in our tertiary institution across body mass index (BMI) groups and different surgical incisions.

METHOD

In this historical cohort study, we reviewed medical records of patients with a BMI ≥ 40 kg·m-2 undergoing elective Cesarean delivery between July 2014 and December 2020. We collected data on patient characteristics, anesthetic and surgical technique, and procedural times. For data analysis, we stratified patients by BMI into three different groups: 40.0-49.9 kg·m-2, 50.0-59.9 kg·m-2, and ≥ 60.0 kg·m-2.

RESULTS

We included 396 deliveries, distributed as follows: 258 with a BMI 40.0-49.9 kg·m-2, 112 with a BMI 50.0-59.9 kg·m-2, and 26 with a BMI ≥ 60.0 kg·m-2. For patients with a BMI 40.0-49.9 kg·m-2, the anesthetic technique of first choice was predominantly spinal anesthesia (71%), whereas for those with a BMI ≥ 60.0 kg·m-2, spinal anesthesia was never used as the anesthetic of first choice. With regard to the surgical incision, spinal anesthesia was almost exclusively used for patients undergoing Pfannenstiel incision and was rarely used for a higher supra- or infraumbilical transverse or midline incision. The overall incidence of general anesthesia was low (7/396, 1.8%). Anesthetic time, surgical time, and operating room time increased almost twofold in patients with a BMI ≥ 60.0 kg·m-2 compared with those with a BMI of 40.0-49.9 kg·m-2.

CONCLUSION

Neuraxial anesthesia was successfully used in approximately 98% of patients with class 3 obesity undergoing elective Cesarean delivery. The choice of regional anesthesia technique varied with increasing BMI and with the planned surgical incision. Procedural times increased with increasing BMI. This information should prove useful for comparing anesthetic choices and outcomes in this challenging population.