Anticipate Complications

- 1) Pneumothorax can occur with higher PIP. Sudden increases in PIP and/or hemodynamic instability may indicate pneumothorax.
- 2) Pneumomediastinum with subcutaneous emphysema can also develop with the use of high PEEP (typically from dissection of air into the adventitia of small bronchi/bronchioles). The development of crepitus across the chest, neck, and/or upper extremities suggests the presence of this condition. Tension physiology from pneumomediastinum is EXCEEDINGLY rare and usually no intervention is needed.
- 3) Acute kidney injury leading to renal failure is a genuine threat to seriously ill COVID-19 patients. Patients unable to make urine can develop fatal arrhythmias from electrolyte abnormalities and acidotic blood. They need to be evacuated to a location capable of renal replacement therapy as soon as possible.
  - Oliguria is defined as less than 0.5 mL/kg/hour of urine output (UOP).
  - Oliguric patients should receive a bolus of 500 cc crystalloid. This may be repeated once if UOP does not improve. If the patient remains oliguric after a 1L bolus, consider the onset of acute tubular necrosis (ATN), especially if UOP remains low for more than 6 hours.
  - As formal creatinine testing for acute kidney injury (AKI) is not likely to be available, consider urine dipstick testing with attention to specific gravity, proteinuria, and hematuria:
    - An abnormally low (dilute) specific gravity in the setting of oliguria suggests tubular damage and the inability to concentrate urine.
    - Significant proteinuria can be seen in ATN; however, this is not specific and can be seen in a variety of acute medical conditions.
    - Hematuria may suggest the presence of myoglobinuria – consider rhabdomyolysis as a cause of acute kidney injury.
  - If UOP suddenly declines or stops, flushing the Foley and/or performing a bladder ultrasound scan can help determine if the problem is mechanical (Foley blockage) or organic (true kidney injury).
  - Once ATN sets in, do not aggressively fluid resuscitate or diurese simply to meet UOP goals. Use alternative markers of fluid responsiveness (like blood pressure response to passive straight leg raise) to help determine the need for further fluids and vasopressor medications.
  - Monitor closely for the development of electrolyte disturbances, specifically metabolic acidosis and hyperkalemia. Use medical management of hyperkalemia as appropriate. The JTS CPG on Hyperkalemia and Dialysis in the Deployed Setting describes field-expedient techniques for peritoneal dialysis; however, this should be done in concert with teleconsultation.