Abstract
This study compares the frequency of hospital-to-hospital transportation events and associated life-threatening deterioration during transport among patients with acute lower respiratory tract illness during vs before the COVID-19 pandemic.
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).
Table. Characteristics of Interhospital Transports of Patients With Acute LRTI Before and During the COVID-19 Pandemica.
| Ground transport | Air transport | |||||
|---|---|---|---|---|---|---|
| No. (%) | Pandemic vs prepandemic, aOR (95% CI)b | No. (%) | Pandemic vs prepandemic, aOR (95% CI) | |||
| Prepandemic, Jan 2019-Feb 2020 | Pandemic, Mar 2020-Feb 2021 | Prepandemic, Jan 2019-Feb 2020 | Pandemic, Mar 2020-Feb 2021 | |||
| No. | 39 393 | 37 117 | 3993 | 4856 | ||
| Age, y | ||||||
| 0-17 | 10 550 (26.8) | 3379 (9.1) | 783 (19.6) | 444 (9.1) | ||
| 18-64 | 13 076 (33.2) | 15 655 (42.2) | 1662 (41.6) | 2224 (45.8) | ||
| ≥65 | 15 055 (38.2) | 17 537 (47.3) | 1528 (38.3) | 2149 (44.2) | ||
| Unknown | 712 (1.8) | 546 (1.5) | 20 (0.50) | 39 (0.80) | ||
| Sex | ||||||
| Female | 17 932 (45.5) | 16 562 (44.6) | 1714 (42.9) | 2052 (42.3) | ||
| Male | 21 228 (53.9) | 20 380 (54.9) | 2243 (56.2) | 2777 (57.1) | ||
| Unknown | 233 (0.59) | 175 (0.47) | 36 (0.90) | 27 (0.55) | ||
| Initial acuityc | ||||||
| Lower acuity (green) | 18 001 (45.7) | 16 497 (44.5) | 52 (1.3) | 35 (0.7) | ||
| Emergent (yellow) | 10 535 (26.7) | 9462 (25.5) | 1314 (32.9) | 1571 (32.3) | ||
| Critical (red) | 2282 (5.8) | 1993 (5.4) | 2349 (58.8) | 2960 (60.8) | ||
| Unknown | 8575 (21.8) | 9165 (24.7) | 278 (7.0) | 290 (6.0) | ||
| Transport unit level of care | ||||||
| Basic life support | 4043 (10.3) | 4285 (11.5) | NA | NA | ||
| Advanced life support | 31 595 (80.2) | 29 413 (79.2) | 541 (13.6) | 541 (11.1) | ||
| Specialty critical care | 3755 (9.5) | 3419 (9.2) | 3451 (86.4) | 4312 (88.8) | ||
| Unknown | 0 | 0 | 1 (0.03) | 3 (0.25) | ||
| US Census region | ||||||
| Midwest | 8073 (20.5) | 8165 (22.0) | 649 (16.3) | 882 (18.1) | ||
| Northeast | 4652 (11.8) | 3625 (9.8) | 548 (13.7) | 487 (10.0) | ||
| South | 18 606 (47.2) | 18 814 (50.7) | 1842 (46.1) | 2315 (47.6) | ||
| West | 8052 (20.4) | 6456 (17.4) | 954 (23.9) | 1172 (24.1) | ||
| Unknown | 10 (0.03) | 57 (0.15) | 0 | 0 | ||
| Outcome measures | ||||||
| Indicators of decompensation during transport | ||||||
| Cardiac arrest resuscitationd | 72 (0.18) | 81 (0.22) | 1.15 (0.83-1.60) | 163 (4.1) | 162 (3.3) | 0.76 (0.60-0.95) |
| Advanced airway placemente | 83 (0.21) | 83 (0.22) | 1.03 (0.75-1.42) | 82 (2.1) | 72 (1.5) | 0.76 (0.55-1.06) |
| NIPPV initiationf | 1280 (3.2) | 1003 (2.7) | 0.68 (0.62-0.74) | 55 (1.4) | 60 (1.2) | 1.07 (0.73-1.57) |
Abbreviations: aOR, adjusted odds ratio; LRTI, lower respiratory tract illness; NA, not applicable; NIPPV, noninvasive positive pressure ventilation.
Suspected LRTI includes all International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) primary/secondary impression codes found using the National Emergency Medical Services Information System (NEMSIS) online Data Cube search terms (respiratory distress, respiratory failure, respiratory disorder, bronchitis, influenza, pneumonia, coronavirus, COVID, not foreign body) in addition to the legacy COVID-19 ICD-10 codes defined by the Centers for Disease Control and Prevention.6 Data in the table are limited to at least 1 encounter per month between January 1, 2019, and February 28, 2021, in 1252 of 8571 consistently reporting emergency medical services agencies.
Adjusted for age, sex, initial acuity, transport unit level of care, and US Census region using logistic regression.
Patients who were dead at time of EMS arrival for pickup (n = 25) are not reported in the table (NEMSIS Data Dictionary: https://nemsis.org/media/nemsis_v3/release-3.4.0/DataDictionary/PDFHTML/DEMEMS/NEMSISDataDictionary.pdf).
Attempted defibrillation, attempted ventilation, initiated chest compressions, not attempted–considered futile, not attempted–do-not-resuscitate orders.
Combitube intubation, double lumen supraglottic intubation, laryngeal mask airway (LMA) intubation, not-otherwise-specified intubation, orotracheal intubation, rapid sequence intubation, single lumen supraglottic intubation, tracheal intubation through LMA, endotracheal intubation, and intubation.
Continuous positive airway pressure, bilevel positive airway pressure, assisted ventilation with bag valve mask, oral airway placement, and nasal airway placement.
Figure. EMS Interhospital Ground and Air Transportation Events in Patients With Acute LRTI in the US, January 1, 2019, to February 28, 2021.
Panels A and C depict trends in the 30-day rolling average of daily interhospital transports for prepandemic (January 2019-February 2020) and pandemic (beginning March 2020 based on the World Health Organization declaration of pandemic; blue area) periods for those patients with documented primary or secondary impressions of emergency medical services (EMS) personnel suggestive of acute lower respiratory tract illness (LRTI) transported by ground and air. Panels B and D depict the percentage change in pandemic vs prepandemic transport counts of patients with acute LRTI in each pandemic wave transported by ground and air. A value below the baseline represents a decline in transports during the pandemic as compared with the same time period during the prior year; values above the baseline represent an increase in transports during the pandemic as compared with the same time period during the prior year. The dashed lines in panels A and C separate the pandemic period into wave 1 (March-May 2020), wave 2 (June-August 2020), and wave 3 (September 2020-February 2021). Trends are limited to data from 1252 EMS agencies from all US Census regions that reported data in each month over the study period.
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.
Section Editors: Jody W. Zylke, MD, Deputy Editor; Kristin Walter, MD, Associate Editor.
eMethods
eTable 1. Codes Defining Treated Patients
eTable 2. Codes Defining Lower Respiratory Tract Illness
eTable 3. Codes Defining Cardiac Arrest Resuscitation
eTable 4. Codes Defining Advanced Airway Procedure
eTable 5. Codes Defining NIPPV Initiation
eTable 6. Codes Used to Defined Advanced Airways Procedures
eTable 7. Codes Used to Define NIPPV Initiation
eReference
References
- 1.Kadri SS, Sun J, Lawandi A, et al. Association between caseload surge and COVID-19 survival in 558 US hospitals, March to August 2020. Ann Intern Med. 2021;174(9):1240-1251. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Payet C, Polazzi S, Rimmelé T, Duclos A. Mortality among noncoronavirus disease 2019 critically ill patients attributable to the pandemic in France. Crit Care Med. 2022;50(1):138-143. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Troncoso RD Jr, Garfinkel EM, Leon D, et al. Decision making and interventions during interfacility transport of high-acuity patients with severe acute respiratory syndrome coronavirus 2 infection. Air Med J. 2021;40(4):220-224. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Allen R, Wanersdorfer K, Zebley J, Shapiro G, Coullahan T, Sarani B. Interhospital transfer of critically ill patients because of coronavirus disease 19–related respiratory failure. Air Med J. 2020;39(6):498-501. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Painvin B, Messet H, Rodriguez M, et al. Inter-hospital transport of critically ill patients to manage the intensive care unit surge during the COVID-19 pandemic in France. Ann Intensive Care. 2021;11(1):54. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Kadri SS, Gundrum J, Warner S, et al. Uptake and accuracy of the diagnosis code for COVID-19 among US hospitalizations. JAMA. 2020;324(24):2553-2554. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
eMethods
eTable 1. Codes Defining Treated Patients
eTable 2. Codes Defining Lower Respiratory Tract Illness
eTable 3. Codes Defining Cardiac Arrest Resuscitation
eTable 4. Codes Defining Advanced Airway Procedure
eTable 5. Codes Defining NIPPV Initiation
eTable 6. Codes Used to Defined Advanced Airways Procedures
eTable 7. Codes Used to Define NIPPV Initiation
eReference