Arginine in the Critical Care Setting

1. Minhao Zhou and
2. Robert G. Martindale

 

Abstract

Arginine is a nonessential amino acid in the normal physiological state that becomes conditionally essential during periods of hypermetabolic stress. Recent literature supports the hypothesis that arginine plays an important role in the intermediary metabolism of the critically ill patient. Current critical care literature is conflicting on arginine use in the clinical setting, with some proposing it as a panacea, whereas others report it as poison. Multiple individual reports and at least 5 major meta-analyses using combinations of immune-modulating nutrients have reported mostly beneficial results, but few have evaluated the effects of arginine when given as a single supplemental nutrient. This review attempts to objectively analyze the literature and evaluate the potential role of arginine in the critical care setting.

Care of the critically ill patient has changed dramatically in the past 5 y. These changes have been driven by evidence-based reports of decreased morbidity and mortality (1). These well-designed prospective randomized trials have focused on meticulous glycemic control, limiting ventilator tidal volumes in acute lung injury/adult respiratory distress syndrome, timing of sepsis resuscitation, use of steroids, activated protein C, and intensivist lead critical care teams. These interventions and others have been summarized in the Society of Critical Care Medicine Surviving Sepsis Campaign (1). Nutritional support has always been an integral part of critical care but was conspicuously absent from the Surviving Sepsis Guidelines. Nutrition was probably omitted, because consistent studies reporting benefits in lowering mortality are lacking. Recently, however, 2 well-designed clinical studies reported lower morbidity and mortality with early (<48 h) feeding (2,3).

The use of immune-modulating specific nutrients and formulas has become routine in the critical care setting in many well recognized major institutions (4). At least 6 so-called immune-modulating formulas are currently commercially available in the US. Some combination of the nutrients arginine, n-3 fatty acids, glutamine, antioxidants, and nucleic acids are those most commonly found in these formulas. Arginine, one of the key components of these formulas, has gained specific attention and has been reported by some to be a panacea, whereas others consider it a poison in the intensive care unit (ICU)⁴ setting. This brief review will attempt to objectively evaluate the current concepts supported by clinical or experimental data regarding the use of arginine in the critical care setting. 

Witma Aptriyana