Abstract
To the Editor:
The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral pandemic is an unprecedented challenge to health care systems and workers. Patients with disease progression become critically ill rapidly, developing acute kidney injury and a hypercoagulable state in addition to severe respiratory failure. Critical care units filled rapidly with these patients, and likely never before have entire units been occupied by patients with an identical admitting diagnosis: coronavirus disease 2019 (COVID-19; U07.1, International Classification of Diseases, Tenth Edition, Clinical Modification). Patients differ in terms of age, comorbidities, and manifestations in addition to respiratory failure, but are remarkably similar, more alike than different. It is challenging to keep track of more than 100 daily arterial blood gas (ABG) determinations, multiple medicated infusions, and clinical status that can change in an instant, among many “moving parts.”
By Executive Order of the Governor of New York State, every acute care hospital in the state was mandated to double its intensive care unit (ICU) bed capacity—in our case from 128 beds to more than 250—by creation of temporary ICUs in heretofore non-critical care areas. Staffing for the makeshift ICUs was drawn from existing hospital staff and volunteers, with supervision by ICU professionals, but some assigned staff had little or no prior critical care training or experience. Clinical protocols were revised and standardized while training was provided concurrently. Recognizing that the sickest patients should be cared for in authentic ICUs by experienced personnel insofar as possible, intra-facility transfer of patients was anticipated as their clinical conditions changed for better or worse.
The need for a simple system of patient classification useful for triage, communication, and resource utilization became apparent immediately.
Tier 1: The Most Critically Ill Patients, Characterized by Any Criterion
Requirement for neuromuscular blockade (for ventilator dys-synchrony)
P:F <100 on FI
Positive end-expiratory pressure (PEEP) >12 cm H2O
Hemodynamic instability (≥2 vasopressors or escalating doses of a single agent)
Requirement for 1:1 nursing care (e.g., mechanical circulatory assistance)
Tier 2: Any Patient with Critical Illness Not Classified as Tier 1 or Tier 3 (May be a Candidate for Transfer to a Temporary ICU)
Mechanical ventilation but no requirement for neuromuscular blockade
P:F >100 on FI
PEEP 10–12 cm H2O
Single vasopressor at a stable or decreasing dose
Standard nurse staffing requirement
Continuous renal replacement therapy permissible, provided unit has the capability
Tier 3: Non-Critically Ill and Ready for Transfer to a Lower Level of Care Including a Temporary ICU (Must Meet All Criteria)
Weaning or liberated from mechanical ventilation with diminished or absent need for sedation; may require non-invasive ventilation
P:F ≥150 on FI
PEEP <10 cm H2O
Normal hemodynamics without need for a vasopressor
Intermittent (conventional) hemodialysis permissible, provided unit has the capability
Regarding resource utilization, in view of the rapid, unpredictable changes in condition and the protracted requirement for mechanical ventilation exhibited by patients with COVID-19 respiratory failure, Tier 1 patients did not receive daily sedation holidays, and underwent ABG determinations every four hours. Tier 2 patients underwent ABGs every six hours, whereas Tier 3 patients received ABGs every 12 hours at most. Clinicians unfamiliar with the patient could gain gestalt at a glance. Patients who deteriorated to Tier 1 in a temporary ICU were transferred to an authentic unit, whereas patients who improved to Tier 2 or 3 were transferred from an authentic ICU to a temporary one if the bed was required.
Because of the nature of the crisis, the tiered system was evaluated during patient care prospectively in the surgical ICU for 48 hours before adoption by all critical care areas hospital wide. The system remains in place as the crisis in New York City enters its fifth week.