Background
Methods
Study design
Activity | Phase of the project | Responsible person |
---|---|---|
Determining eligibility for participation, agreeing of the study protocol and required safety measures | Planning | Research team |
Employing agreed selection criteria | Selection of patients from medical records | Cardiologist |
Confirmation of eligibility | Contact with patients: pre-screening for eligibility, inquiring of willingness to receive further information | Cardiologist |
Confirmation of eligibility | Contact with patients (n = 22): informing of the study, screening of health through a questionnaire, invitation to participate to tests assessing physical capacity | Researcher |
Confirmation of eligibility, use of exercise information to the experiments, employing termination criteria, constant monitoring | Assessment of physical capacity (n = 20), graded bicycle ergometer test, measurement of ECG, acquiring informed consent to participate to the experimental study | Researchers, expert in exercise physiology, medical doctor (on site) |
Planning of experiment, employing agreed termination criteria, constant health monitoring | Randomised controlled study (n = 18 × 4): exercise or rest at − 15 °C or + 22 °C (baseline, exercise, follow-up), assessment of cardiovascular function (HR, ECG, BP), perceived exertion, thermal sensations, assessment of possible other symptoms | Researchers, emergency nurse, medical doctor (monitoring on call) |
Post-experiment follow-up | Follow-up after the experiment (n = 18), 24 h monitoring of BP and ECG | Researcher, participant |
Ethics approval and consent to participate
Study population
Intervention
Safety measures taking place prior to the controlled experiments
Intervention
Safety monitoring during the experimental exposure to cold temperature and exercise
Follow-up in the laboratory and at home
Results
Testing of physical capacity
Problems observed during the simulation | Resulting changes in the safety protocol |
---|---|
If patient collapsed to the left side of ergometer, the placement of furniture prohibited unobstructed access to the patient. | Preferable treatment area designated. Relocation of furniture and equipment. Plan B discussed. |
If patient collapsed to the right side of the ergometer, monitor cords tangled around it. These had to be temporarily detached, which lead to loss of monitoring during the emergency. | Monitor cords were appropriately bundled, elevated with an adapter, and fed to the monitors ipsilaterally to treatment area. Changes in crew seating and task allocation to ensure non-traumatic fall over to treatment area. Plan B discussed. |
Short monitor cords prevented turning the ECG monitor towards the person assessing the collapsed patient. | Relocation of the ECG monitor, AED, and staff emergency posts within treatment area. Monitor cording improved. Plan B discussed. |
Delay in finding the telephone for an emergency call. | Telephone kept in standard position. A staff member designated in charge of the telephone. Relevant telephone numbers mounted in strategic places around the lab, ensuring they are visible from treatment area also. |
Uncertainty of the exact address of the lab facility during the emergency call. Describing the different access points required some concentration. | Printouts with institution name, coordinates, street address, room, and location map created. Printouts mounted in strategic places around the lab, ensuring they are visible from treatment area also. |
The presumed EMS pathway from outdoors to the lab has a section that is too narrow for gurdeys. | Appropriate pathway established. Alternative pathway established. Crew trained. |
Doors of the alternative EMS pathway are locked. Difficulty in identifying the appropriate keys. Attending to the problem removes 1 staff member from the BLS team. Risk of getting locked out, which would relocate another staff member. | Appropriate pathway established. Alternative pathway established. Crew trained. Relevant keys kept in standard position. A crewmember designated in charge of EMS call, door opening task, and guiding EMS through the building. |
AED patches are the type that require removing ECG leads. In a deteriorating patient-scenario, this means a trade-off between being able to monitor development of the cardiologic status and being prepared for immediate defibrillation. | Different type of AED patches obtained. Backup patches obtained. |
Patient profusely sweaty from ergometer strain. May compromise optimal performance of AED. | Towels (and razors) at a hands reach in treatment area. |
Time delay between collapse and defibrillation. | AED placement, patch attachment, placement of accessories (towels, razors) within the treatment area checked every day. AED cover detached (adhering to operating manual). |
No closed-loop communication. | Non-technical skills discussed. |
Overlapping actions. | Specific tasks during an emergency allocated for each staff member. These are revised and orally confirmed daily prior to initiating each experiment. BLS algorithm visible from all angles of treatment area. |
Emerging health issues during the controlled experiments and follow-up
Objective finding | Symptom of participant | Safety measures |
---|---|---|
Ventricular irregular HR of one participant for a few minutes while walking in a warm environment. The measured BP during this period was 76/46 mmHg and when repeated 111/53 mmHg. The RR interval, however, did not deviate from the values measured during the reminder of the experiment. | No symptoms | The participant was instructed to consult a MD because of low BP during baseline rest. A low BP needs to be considered because of post-exercise hypotension. |
One measurement conducted while exercising in the cold was terminated because of ST-depression exceeding 2 mm and detecting adjacent ventricular ectopic beats. | No symptoms | The ECG returned to normal after cessation of exercise. |
Four participants experienced post-exercise hypotension. Three of these occurred after walking in a warm environment (BP 60/35 mmHg, 68/35 mmHg and 87/50 mmHg) and one after exercise in the cold (BP 87/59 mmHg) | Nausea, dizziness | Participants were instructed to lie down until BP recovered to normal. This occurred briefly, after ca. 5 min. |
A total of six participants experienced milder post-exercise hypotension (systolic BP < 100 mmHg). In four cases these occurred after exercise in warm and for two participants in a cold environment. | No symptoms | Constant monitoring the responses and inquiries of subjective symptoms. No additional measures taken. |