Impact of Communication Delays on Anesthesia Response to Medical Emergencies and Ultrasound-Guided Regional Anesthesia

Background and Rationale The number of people travelling to space is increasing rapidly with increased government funded exploration, private space industry development, and even space tourism. Although historically the risk of traumatic injuries and medical emergencies has been low, with the frequency, complexity and duration of missions increasing, emergencies can be expected. Treating traumatic injuries and medical emergencies in space comes with a high level of difficulty given physiologic changes associated with microgravity (fluid shift, dehydration, altered autonomic responses, airway edema, etc) and travel outside of earth magnetosphere exposing astronauts to higher ambient radiation levels (inducing immune suppression). Most analgesic medications have some degree of cognitive impact (drowsiness, mental fogging, or confusion) which could compromise astronauts ability to participate in critical activities. Deep sedation or general anesthesia would be very risky given the physiologic changes and the difficulty of advance airway maneuvers in microgravity. For these reasons, regional anesthesia has been suggested as a solution for pain control with minimal hemodynamic and cognitive side effects. Previous commentators have suggested that regional anesthesia is a solution to pain management and to allow surgical procedures in microgravity. However, since nerve blocks are highly specialized skills and responding to medical emergencies in general requires extensive medical training, it is likely that astronauts will require guidance from earth based medical professionals.

Planning for medical emergencies will be an essential part of preparation and training. In the more than 50 years of space exploration, NASA has selected 360 astronaut candidates, 33 of them have been physicians. On most missions the crew includes a "Chief Medical Officer" (CMO), an astronaut chosen to provide in-flight medical care. The CMO's receive 40 hours of pre-mission basic medical training on the use of essential on-orbit medical equipment and the recognition of a variety of medical conditions. On missions to the ISS the CMO's can consult earth-based flight surgeons and injured persons can be evacuated to a treatment facility on earth, however with further exploration communication becomes delayed and evacuation impossible.

An approximate three-second minimum communication delay currently exists between Earth and Moon, but larger data transfers using information dense communication (like video consultation) a delay of up to 163 seconds is predicted. With such a long delay, the ability for real time communication is lost. The acting CMO will likely need to communicate with terrestrial-based flight surgeons and any extended delay in emergency medical treatment would be expected to increase negative outcomes on patient care. The purpose of this study is to assess the degree of impact of a communication delay on remote mentorship of a procedure (nerve block). Secondly, to assess the impact on accuracy of and timing of response to a medical emergency.

Statement of Research Questions

Hypotheses:

The investigators hypothesize that a communication delay of 80 seconds compared to no delay will be associated with longer procedural times and decreased quality during brachial plexus block scanning. Secondly, the communication delay will be associated with more errors in treatment and a delay of essential treatments in a medical emergency.

Objectives:

1. Quantify the difference (communication delay versus no delay) in time to identify critical structures while scanning brachial plexus block sonoanatomy and time to essential treatment during a medical emergency.
2. Quantify the difference (communication delay versus no delay) in quality and ease of imaging while scanning brachial plexus block sonoanatomy.
3. Quantify the difference in completeness of emergency treatment using a composite measure (communication delay versus no delay).
4. Describe the challenges and solutions for team functioning and remote mentorship when a communication delay exists.

Methods

Study Design This is a within-subjects, mixed-methods, simulation-based randomized study. Participants will be placed in medical teams of 3 participants. Every team will complete both the no communication delay and 80-second communication delay. Teams will be randomly assigned the order in which they perform each condition. All teams will perform the same scenarios and emergencies. Teams will communicate via real-time video chat or video recording (delay) with anesthesiologists experienced in regional anesthesia.

Recruitment and Allocation The investigators will recruit medical students from Dalhousie University and Canadian Armed Forces (CAF) medical technicians at a minimum of Rank Qualification Medical Technician Private or CAF nurses for this study. The investigators intend to recruit 42 students, medics or nurses placed in 14 teams of 3 participants.

Recruitment will be done via email advertisements and physical posters for medical students. For military personnel, the opportunity will be disseminated via email through the unit training cell to avoid real or perceived coercion from the chain of command.

Training session Recruited participants will be given a 4-hour training session on the basics of ultrasound theory, knobology, needling skills, local anesthetics, sono-anatomy, and complications of nerve blocks. This session will be developed and led by fellowship trained regional anesthesiologists. There will be opportunities to practice image acquisition on live models with feedback. This session will take place within 4 weeks of the study.

Simulation scenarios Each team will run two scenarios during the same half day session. Every team will complete both the no communication delay and communication delay (80 seconds) conditions. The order of conditions (delay vs no delay), order of emergency scenario, and the type of block requested will be randomized. One scenario will be completed followed by a debriefing session. Then the team will complete a second scenario with a different nerve block and emergency, followed again by a debriefing session. The scenarios and nerve blocks will be different so the condition (delay vs no delay) will also be randomized.

Each team will have 3 participants (one lead participant with supporting team members) (referred to here as the "treating team"). Teams will be prompted that safe decision making and action is crucial in these scenarios. Once the team enters the simulation space, they will be able to ask for assistance from a "remote" team of experts. In a nearby room, a group of regional anesthesiologists (co-investigators) will guide the participants through the scenario (referred to here as "mission control"). The lead participant will be asked to scan a live model to identify the critical anatomical structures needed to perform a brachial plexus block (axillary or supraclavicular approach).

The scenario will then shift to a response to a medical emergency related to the block (local anesthetic systemic toxicity (LAST) or anaphylaxis). The scenario will prompt quick action for a potentially life-threatening situation. As with the ultrasound scanning for the block, teams can ask for help from the remote team of experts in 'mission control' as many times as they deem necessary.

Debriefing Following the scenario, the treating team and the mission control team will meet in the same room to debrief the scenario. An investigator who is trained in debriefing simulation scenarios will lead the debriefing session. The discussion will focus on the following objectives: 1. Safe conduct of a nerve block, including identification of sonoanatomy, 2. Timely response to the medical emergency, and 3. Clear communication among team members to provide safe care.

Statistical analysis and power calculation Quantitative Demographics will be collected (age, gender, prior medical training, experience with nerve blocks) and reported in aggregate for the purposes of external validity and generalizability. Outcomes will be compared between no communication delay versus communication delay (within subjects, paired data). Univariate comparisons will be analyzed for ordinal outcomes (ease of image acquisition, quality of images, ease of needle placement, composite score), and continuous data (time to identification of anatomy, time to definitive treatment).

Qualitative Two investigators will separately review the transcripts for themes using inductive coding as they become available. The codes will be analyzed, and eventually grouped into categories that highlight the underlying themes. The investigators will meet to discuss and come to consensus regarding emerging themes and larger categories after every 5 transcripts analyzed. Illustrative quotes will be used when reporting the themes.

Sample Size The sample size is based on time for scanning and time to respond to a medical emergency. While performance time is only one marker of ease and success for regional anesthesia, because this study only includes scanning and identification of sonoanatomy (does not involve needle passing and injection in a model), time was felt to be an important outcome for sample size calculation. The average time is 5-6 minutes (standard deviation 1.8-2.0) to perform a brachial plexus block. A paper examined the difference in performance time from early to late learning curve, finding that early in the learning curve performance times between 1.5 to 3 times that of the average performance time. Assuming an average time of 6 minutes (standard deviation 2.0) compared to 9 minutes (1.5x the baseline), an alpha of 0.05, power of 80%, and matched pairs t-test, a sample size of 6 teams would be needed (G*Power, Dusseldorf, Germany).

The investigators were unable to locate a study directly addressing treatment delays for LAST, or anaphylaxis. In a study of out-of-hospital cardiac arrest, the median time to bystander CPR was 2 minutes. Patient who received CPR 4-5 minutes following arrest had much worse survival (odds ratio 0.73) compared to those that received CPR within 1 minute of arrest. The investigators converted the study median 2.0 (IQR 1.0 - 5.0) to mean 2.67 (SD 2.97) using Wan and colleagues method. Assuming an alpha of 0.05, power of 80%, and matched pairs t-test, a total sample size of 11 teams is needed to detect a difference of 3 minutes in time to definitive treatment (G*Power, Dusseldorf, Germany). With a 5-point composite score, the study should be able to detect a difference of 1.5 assuming SD of 0.75, alpha 5%, and power 80% with 12 teams. Given the uncertainty in the estimate of average time to treatment, the investigators will aim to recruit an additional 3 team for a total of 14 teams (42 individuals).

Regarding qualitative analysis, the investigators expect to reach the point of data saturation between 10 to 12 groups (no new themes are identified). Our justification for this sample is somewhat pragmatic but it is also expected that the variety and quality of responses will be greater than individual interviews given multiple participants in a team, and the learner-centered debriefing style led by expert debriefers. Furthermore, this sample size is consistent with previous research on team functioning in medical simulation.