Iatrogenic salt water drowning and the hazards of a high central venous pressure

Abstract

Current teaching and guidelines suggest that aggressive fluid resuscitation is the best initial approach to the patient with hemodynamic instability. The source of this wisdom is difficult to discern, however, Early Goal Directed therapy (EGDT) as championed by Rivers et al. and the Surviving Sepsis Campaign Guidelines appears to have established this as the irrefutable truth. However, over the last decade it has become clear that aggressive fluid resuscitation leading to fluid overload is associated with increased morbidity and mortality across a diverse group of patients, including patients with severe sepsis as well as elective surgical and trauma patients and those with pancreatitis. Excessive fluid administration results in increased interstitial fluid in vital organs leading to impaired renal, hepatic and cardiac function. Increased extra-vascular lung water (EVLW) is particularly lethal, leading to iatrogenic salt water drowning. EGDT and the Surviving Sepsis Campaign Guidelines recommend targeting a central venous pressure (CVP) > 8 mmHg. A CVP > 8 mmHg has been demonstrated to decrease microcirculatory flow, as well as renal blood flow and is associated with an increased risk of renal failure and death. Normal saline (0.9% salt solution) as compared to balanced electrolyte solutions is associated with a greater risk of acute kidney injury and death. This paper reviews the adverse effects of large volume resuscitation, a high CVP and the excessive use of normal saline.

Keywords: Acute respiratory distress syndrome; Central venous pressure; Extra-vascular lung water; Fluid; Fluid balance; Fluid overload; ICU; Lactate Ringers Solution; Lung water; Mean circulatory filling pressure; Normal saline; Sepsis.

Figure 1

Fourty-four-year old male with Pneumococcal pneumonia. (a) Initial chest radiograph (CXR) in emergency department. (b) CXR four hours later after four liters of crystalloid (patient now intubated). (c) CXR 12 hours after admission, after 9 liters of crystalloid, central venous pressure (CVP) = 10 mmHg. Patient died six hours later of refractory hypoxemia.