Study design and setting
A prospective cohort study was implemented to assess the incidence of prehospital sudden deterioration among COVID-19 patients transported by public ambulances in Addis Ababa, Ethiopia. Addis Ababa is the capital city of Ethiopia and the seat of African Union headquarter. In response to the COVID-19 outbreak in Ethiopia, the Addis Ababa city health bureau in collaboration with the Federal Ministry of Health established emergency operating centers (EOC) to provide prehospital care services to COVID-19 patients. The city has 10 dispatch centers and one central dispatch center dedicated to providing emergency medical services to COVID-19 patients. The centers have basic and advanced ambulances equipped with essential drugs and equipment. The ambulances were also staffed with different health care professionals including general practitioners and nurses. When an emergency call is received, the closest available ambulance is sent to the place to transport the COVID-19 patient to the nearest COVID-19 centers.
A prospective cohort study was carried out in Addis Ababa, Ethiopia, to assess the incidence of prehospital sudden deterioration among COVID-19 patients transported by public ambulances. Addis Ababa is Ethiopia's capital and the headquarters of the African Union. In response to the COVID-19 outbreak in Ethiopia, the Addis Ababa city health bureau established emergency operating centers (EOC) in collaboration with the Federal Ministry of Health to provide prehospital care services to COVID-19 patients. The city has ten dispatch centers and one central dispatch center dedicated to providing COVID-19 patients with emergency medical services. The centers have basic and advanced ambulances that are outfitted with necessary drugs and equipment. The ambulances were also staffed with a variety of medical personnel, including general practitioners and nurses. When there is an
Eligibility criteria
All successful ambulance dispatch that transported COVID-19 patients aged 12 years and above between May to August 2021 were eligible for inclusion in the study. The exclusion criteria were failed dispatch and incomplete information to determine sudden clinical deterioration during transportation to the receiving facility.
Sample size and sampling procedure
The sample size for the study was calculated using single population proportion formula with the following consideration. The level of confidence (α) was set at 0.05 (Z (1-α) = 1.96) and the margin of error was considered at 0.05. It was reported that adverse events in the prehospital setting are one of the leading factors that cause sudden clinical deterioration in the prehospital setting (16). Thus, the proportion of adverse events in the prehospital setting among COVID-19 patients in Addis Ababa was taken as 44.2% (31). Considering, 10% for contingency and design effect of 1.5, the calculated sample size was 625. A cohort of COVID-19 patients who met eligibility criteria and were consecutively transported between May to August 2021 by Addis Ababa’s EOC was purposively recruited to the study.
Data collection technique
The data collection tool was prepared by the investigators following reviews of previous works of literature (20,32–34). The data were collected by general practitioners and nurses working on the ambulance at each dispatch center in Addis Ababa. The tool consisted of information such as prehospital response time, source of EMS call, educational background of EMS providers, patients’ demographic data, clinical characteristics of the patients, and prehospital care provided to the patients.
Outcome measures
The outcome of interest was sudden clinical deterioration during the prehospital transportation. The event must have occurred between the time of departure from the referring facility or home and the time of arrival at the receiving facility. Prehospital sudden clinical deterioration was measured by evaluating a change in any of the following physiological status components from the last recorded observations to the most recent (33). These physiological changes include (A) Change in pulse rate: either, a sudden increase in pulse rate of 20 beats per minute above the previous reading, or the recently recorded pulse rate of greater than 110 beats per minute, or less than 50 beats per minute (33). (B) Change in blood pressure: either, a sudden drop of blood pressure of 20 mmHg or more since the last reading, or a fall below 90 mmHg systolic in the recent reading (33). (C) Change in respiratory rate: either, a sudden increase in respiratory rate of 10 breaths per minute above previous reading, or greater than 29 breaths per minute or less than 10 per breaths minute (33). (D) Change in the conscious state: either, a sudden decrease in a conscious state of 2 points in either component (eye-opening, best verbal response, best motor response) of the Glasgow Coma Scale (GCS) or a newly recorded GCS score of <13 (33,35). (D) Cardio-pulmonary arrest (33).
Data analysis
Epi data version 4.2 was used for data entry and SPSS version 25 was used for the analysis. Descriptive statistics such as frequency, percentage, mean, and standard deviation were used to summarize the findings, and tables and figures were used to present the information. A modified (Robust) Poisson regression was used to determine relative risk summary metric and predictors of prehospital sudden clinical deterioration. We selected all candidate variables for multivariable analysis using a threshold for inclusion of p < 0.25 from bivariate analysis to control the effect of confounders. After adjusting for potential confounders, a statistically significant association was declared at adjusted relative risk (ARR) ≠ 1with a 95% confidence interval (CI) and a p-value less than 0.05.
Operational definitions and definitions of terms
Sudden prehospital deterioration: the patient was categorized as suddenly deteriorated if there was any change in the components of physiological parameters mentioned under the measurement section from the last recorded observations to the most recent.
Response time: the time from the emergency call until arrival at the scene (36).
On-scene time: the time from arrival at the scene until departure from the scene (36).
Total prehospital time: indicates the time from the emergency call until hospital arrival (36).
Transport time: the time from scene departure until hospital arrival (36).
Queueing delays: refers to delays when no ambulance is available to dispatch (37).