Research Letter January 28, 2022
Frequency and Risk of Emergency Medical Service Interhospital Transportation of Patients With Acute Lower Respiratory Tract Illness During the COVID-19 Pandemic in the US
Sadia H. Sarzynski, Alex Mancera, Clay Mann, et al
JAMA. 2022;327(9):874-877. doi:10.1001/jama.2022.0812
Surges in hospital COVID-19 caseloads are detrimental to patients hospitalized with COVID-191 and other conditions.2 Transporting patients out of hospitals before reaching critically high caseloads might improve outcomes. However, patients with COVID-19 requiring transfer are often unstable3; evidence on the safety of transporting patients with COVID-19 is scarce.4,5 We leveraged a national emergency medical services (EMS) database to compare the frequency of interhospital transportation events and associated life-threatening deterioration during transport among patients with acute lower respiratory tract illness (LRTI) during (vs before) the pandemic.
Methods
A retrospective cohort study was conducted using the National Emergency Medical Services Information System database. This database is composed of standardized data on EMS activations from 48 US states, including data from some individual health systems and private ambulance services. Unique interhospital ground and air transports by EMS agencies that reported continuously for each month from January 1, 2019, through February 28, 2021, were identified. Trends in daily count of transports for patients with EMS-documented primary or secondary impressions of acute LRTI (eTables 1-4 in the Supplement) were calculated for a prepandemic period (January 2019-February 2020) and 3 US pandemic waves (first wave: March-May 2020, second wave: June-August 2020, and third wave: September 2020-February 2021). The change in the aggregate count of transports during each pandemic wave relative to corresponding months in the prior year enabled determination of temporal patterns while accounting for seasonality.
Decompensation during transport of patients with acute LRTI was identified using cardiac arrest resuscitation, advanced airway placement, and initiation of noninvasive positive pressure ventilation (NIPPV) (eTables 5-7 in the Supplement). Logistic regression models were used to determine the adjusted odds ratio (aOR) of each decompensation indicator during the pandemic (vs prepandemic) period by transport method, while controlling for age, sex, baseline acuity, transport unit level of care, and Census region. Python version 3.9.6 (Python Software Foundation) and SAS version 9.4 (SAS Institute) were used for analysis. Given the use of deidentified data, the study was deemed not to require ethics board approval by the Office of Human Subjects Research Protection, National Institutes of Health, under the revised Common Rule.
Results
Of 1 099 351 interhospital transports by 1252 US EMS agencies between January 2019 and February 2021, 85 359 (7.8%) occurred for patients with acute LRTI. Of these, 76 510 (89.6%) were ground and 8849 (10.4%) were air transport. The proportion of transported patients categorized as low, emergent, or critical acuity at transport onset were similar before and during the pandemic (Table).6 Interhospital ground transports for acute LRTI declined from 8512 before the pandemic to 7728 during the first wave (difference, 784; –9.2%; Figure, A and B), but subsequently increased in the second wave from 6261 before the pandemic to 8018 (difference, 1757; 28.1%) and in the third wave from 18 348 before the pandemic to 21 371 (difference, 3023; 16.5%). Air transports increased during all 3 waves (Figure, C) and maximally during the second wave from 702 before the pandemic to 1181 (difference, 479; 68.2%; Figure, D). Yet, air transports continued to represent less than 12% of acute LRTI transports (Figure, C).
The odds of intratransport cardiac arrest resuscitation, advanced airway placements, and NIPPV initiation did not increase during the pandemic (vs prepandemic) period for both ground and air transports (Table). The odds were lower for NIPPV initiation in ground transports (1280 [3.2%] before the pandemic vs 1003 [2.7%] during the pandemic; aOR, 0.68 [95% CI, 0.62-0.74]) and for cardiac arrest resuscitations in air transports (163 [4.1%] before the pandemic vs 162 [3.3%] during the pandemic; aOR, 0.76 [95% CI, 0.60-0.95]).
Discussion
This study of hospital-to-hospital transports for patients with acute LRTI (a population likely enriched for patients with COVID-19 during the pandemic) found no increases in intratransport cardiac arrest, advanced airway placements, or NIPPV initiations during the pandemic (vs prepandemic) period. These findings persisted even as total transports increased in the second and third waves.
Study limitations include a potential lack of national representativeness of the database, an absence of database-specific comorbidity and COVID-19 codes for the study period, and risk of unmeasured confounding given the potential subjectivity in EMS reporting of initial acuity.
These findings increase confidence in the safety of transferring patients with LRTI during the pandemic.
