ICU MANAGEMENT

NEUROLOGIC

The majority of long term sequalae of drowning events are secondary to neurologic injury. Early efforts should be made to improve central nervous system oxygen delivery while providing evidence-based neuroprotection in the post-resuscitative period.

- Maintain adequate oxygenation of SaO2 >92%. *In the intubated post arrest patient, hyperoxia (PaO2 >300mmHg) is associated with poor neurologic outcomes.41 Consider placement of an arterial line to monitor PaO2.
- Maintain systemic mean arterial pressure > 65mmHg to ensure adequate cerebral perfusion (cerebral perfusion pressure = mean arterial pressure – intracranial pressure). Low dose vasopressor support may be necessary. As discussed above, in military drowning patients with an abnormal neurologic exam and persistent hypotension, ICU caregivers must rule out traumatic injury and hemorrhage as a cause of hypotension. * There is no evidence to support invasive intracranial pressure monitoring or supranormal cerebral perfusion pressures.23
- Maintain head of bed at 30 degrees with head midline.
- Only aggressive fever prevention is recommended. Cooling with targeted temperature management is NOT recommended.24

In patients who are still rewarming, aggressive shivering control should be implemented (See Figure 2 on right for an example of shivering management protocol). Significant adverse effects from prolonged shivering include lactic acidosis, elevated intracranial pressure, rhabdomyolysis, discomfort, and interference with monitoring devices.24

Figure 2. Example Shivering Management Protocol

PULMONARY

Aspiration of both seawater and freshwater in relatively small quantities can lead to disruptions in the surfactant equilibrium of the lungs. Reduced surfactant leads to atelectasis which can make patients more prone to atelectrauma and subsequent biotrauma (neutrophil migration and subsequent acute respiratory distress syndrome or sepsis).36,38 Osmotic shifts in the alveoli can lead to noncardiogenic pulmonary edema which results in reduced compliance, right to left shunting, and hypoxemia. Evidence-based care for mechanically ventilated patients should be followed. 2

- Maintain saturation at 92% (or PaO2 between 55-80mmhg) while avoiding hyperoxia.
- Oxygenation should be maintained by titrating fraction of inspired O2 (FIO2) and incremental increases in PEEP, which will help to reduce incidence of barotrauma. Current literature suggests achieving a PaO2>FIO2 ratio of >250.
- Once adequate oxygenation has been achieved, the same PEEP should be maintained for 48 hours without attempts to wean from the ventilator.
- The best available evidence indicates pulmonary surfactant restores in 48 hours. Early attempts at extubation may lead to recurrent pulmonary edema and increased ventilator days.
- Avoid permissive hypercapnia (unless neurologic status is intact) due to concern for concomitant neurologic injury that may worsen with high pCO2.
- A lung protective ventilator strategy should be followed with the goal of preventing barotrauma.
  - Maintain tidal volumes of 6cc/kg of predicted body weight.
  - PEEP strategy as noted above.
  - Maintain plateau pressures < 30 cmH20, Driving pressure <15 cmH20.
  - Consider bronchoscopy for quantitative cultures and foreign body removal if there is concern for aspiration (e.g., sand, seaweed).
  - Patients with prolonged, severe, or refractory hypoxemia should be considered for ECMO; however, drowning patients were not specifically included in landmark ECMO trials (e.g., EOLIA, CESAR). Case reports of ECMO use in profoundly hypothermic patients have demonstrated some success.
- No role for artificial surfactant.

Once adequate oxygenation has been achieved, the same PEEP should be maintained for 48 hours without attempts to wean from the ventilator. The best available evidence indicates pulmonary surfactant restores in 48 hours. Early attempts at extubation may lead to recurrent pulmonary edema and increased ventilator days.

CARDIOVASCULAR

Low output heart failure and lethal dysrhythmias are common in drowning victims. While hypoxemia is the primary driver of these conditions, correction of hypoxemia may not immediately restore normal cardiac function and ICU physicians should be prepared to manage these issues. Reduced cardiac output may lead to cardiogenic component of pulmonary edema or worsen additional organ failure (e.g., cardiorenal syndrome).1

- Consider echocardiogram initially. In patients requiring inotropic support, consider cardiac output monitoring through either noninvasive cardiac output monitoring, pulse contour analysis, or pulmonary artery catheter.
- Maintain MAP goal of >65mmHg. Stroke volume variation can be utilized to identify patients that may be volume responsive and should be given additional crystalloid resuscitation. Judicious fluid resuscitation should be maintained.
- Patients who are not volume responsive and remain hypotensive should receive vasopressor support. Again, be sure to rule out traumatic injury and hemorrhage as a cause of hypotension.
- Patients should remain on continuous telemetry to assess for dysrhythmias.
- EKG or telemetry may demonstrate the presence of Osborne waves or J Waves (extra deflection at the end of the QRS complex) in the hypothermic patient. See Figure 3 below.

Figure 3. Demonstration of Osborn or J-Waves34

HEMATOLOGIC, ENDOCRINE, AND RENAL

Drowning victims requiring the ICU are critically ill and can be prone to the same hematologic, metabolic, and renal pathologies as other ICU patients. There is no evidence that there is clinically significant hemolysis or electrolyte shifts in drowning patients. Rates of renal failure secondary to decreased perfusion during resuscitative efforts or subsequent decreased cardiac output are similar to other cardiac arrest patients.

- No role for routine use of bicarbonate in patients with metabolic acidosis.10
- Maintain euglycemia (140-180mg/dl).25
- Renal failure in the majority of drowning patients is uncommon; however, when present, it may be secondary to decreased perfusion, myoglobinuria or hemoglobinuria.10

INFECTIOUS DISEASE

There is no role for prophylactic antibiotics in drowning victims either in freshwater or saltwater. Furthermore, rates of antimicrobial resistance in bacteria obtained from seawater drowning victims is negligible and broad-spectrum coverage is not indicated.

- Broad spectrum antibiotics to cover both gram-positive and gram-negative bacteria are indicated in patients where drowning occurs in a source with a high pathogen load (UFC >10).20
- Monitor patient for signs and symptoms of pneumonia (new pulmonary infiltrates on imaging, leukocytosis, fever, worsened respiratory status).
- Routine cultures are not required unless specific concern is present.
- Consider bronchoscopy for quantitative cultures or source control of possible aspirated nidus of infection.