High-energy blunt pelvic ring injury incidence and polytrauma caseload in a single level I trauma center during COVID-19 related pseudo-lockdown measures: a retrospective cohort study based on a prospective registry

This retrospective cohort study was based on data prospectively recorded into the institutional Severely Injured Patients’ Registry (SIPR). The SIPR contains around 300 items for each patient admitted with a suspected or confirmed high-energy trauma or polytrauma. Among these items, demographic data, trauma details and mechanism, treatments, outcomes, Abbreviated Injury Scale (AIS) codes [14] and Injury Severity Scores (ISS) [15, 16] are recorded. A trained and accredited study nurse was responsible for AIS and ISS coding [14‐16].

This study was conducted in a 1900-bed urban academic center serving around 500,000 inhabitants (University Hospitals of Geneva, Switzerland) and corresponding to a level I trauma center according to national and international medical authorities’ definitions [17, 18] with about 100–150 patients with an ISS ≥ 16 and 70–100 patients with an ISS ≥ 20 managed each year.

Federal government issued a nation-wide pseudo-lockdown following the COVID-19 pandemic from March 16th to June 19th, 2020 [19, 20]. Measures included social distancing, quarantine, restricted travels, on-line education and office work, sports and leisure facilities’ closure, building sites’ standstill, and limited out-of-the house displacement [19]. Medical resources were mainly reallocated to COVID-19 patients. Minor trauma patients were mostly redirected to other healthcare facilities, but severely injured patients continued to be admitted at the authors’ institution.

The main outcomes were the incidence of high-energy blunt PRI and the absolute number of PP. Inclusion criteria for the incidence of high-energy blunt PRI were: (1) SIPR entry between January 1st, 2014 and December 31st, 2020; (2) ≥ 16 years old; and (3) PRI presence as defined by specific AIS codes (856,100.2 and 856,101.3 corresponding to PRI not further specified; 856,151.2 and 856,152.3 corresponding to PRI with intact posterior arch; 856,161.3, 856,162.4, 856,163.4 and 856,164.5 corresponding to rotationally unstable PRI; 856,171.4, 858,172.4, 856,173.5 and 856,174.5 corresponding to vertically and rotationally unstable PRI) [14]. Corresponding exclusion criteria were: (1) death before Emergency Room (ER) admission; (2) transfer from another institution > 24 h after trauma; (3) penetrating, blast, burn and electrical injuries, drownings; (4) patients living outside the defined institution’s catchment area; (5) any document attesting the patient’s will not to participate in any study. Inclusion criteria for the absolute number of PP were: (1) SIPR entry between January 1st, 2014 and December 31st, 2020; (2) ≥ 16 year old; and (3) ISS ≥ 16 [21]. The ISS cutoff of 16 was chosen as the most common definition of PP found in the literature [21]. Corresponding exclusion criteria were: (1) death before ER admission; (2) transfer from another institution > 24 h after trauma; and (3) any document attesting the patient’s will not to participate in any study. Death before ER admission was an exclusion criterion because of the usual lack of diagnostic assessment in these cases. Transfer from another institution > 24 h after trauma was also an exclusion criterion since initial medical data may be difficult to collect. Penetrating, blast, burn and electrical injuries, as well as drownings, were exclusion criteria because these injury patterns are rare in the authors’ institution and would have added heterogeneity to the study collective. Finally, patients living outside the defined institution’s catchment area were excluded to obtain incidence values for high-energy blunt PRI which were interpreted as an indirect measure of population’s compliance to pseudo-lockdown restrictions. Alternatively, the absolute number of PP was chosen as a general indicator of the level I trauma center activity, without patients’ origin distinction—within or outside the defined catchment area.

The SIPR was used to extract age, gender, residential address (within defined catchment area or not), accident’s date, trauma mechanism, AIS codes, ISS, survival, death’s date if applicable, complications (defined as any serious secondary condition appearing during hospital stay), intensive care unit (ICU) length of stay, total acute hospital length of stay, hemodynamic instability at admission (defined as prehospital systolic blood pressure < 90 mmHg or prehospital heart rate > 100 bpm or need for packed red blood cell (PRBC) in the ER), number of PRBC units received during the first 24 h. Radiological images were reviewed by two authors and PRI classified according to the AO/OTA classification [22]. Only type B and C PRI were considered for this study as they may be associated with hemodynamic instability and usually need surgical fixation [23]. Population description of the defined catchment area of the institution was obtained from the government's Statistics Office [24]. Polytrauma patients were further stratified using ISS cutoffs of 20 (definition of severe trauma in Switzerland) [18] and 24 (definition of critical trauma in some publications) [25].

The incidence of high-energy blunt PRI and the absolute number of PP were individualized for each year period (January 1st to December 31st) and the corresponding pseudo-lockdown period (March 16th to June 19th) from 2014 to 2020. Categorical variables were reported using proportions and continuous variables using medians and interquartile ranges. Because data were exhaustive for the authors’ level I trauma center, no inferential statistics were computed.