Lactic Acidosis and the Role of Sodium Bicarbonate: A Narrative Opinion.

Lactic acidosis occurs commonly and can be a marker of significant physiologic derangements. However what an elevated lactate level and acidemia connotes and what should be done about it is subject to inconsistent interpretations. This review examines the varied etiologies of lactic acidosis, the physiologic consequences, and the known effects of its treatment with sodium bicarbonate. Lactic acidosis is often assumed to be a marker of hypoperfusion, but it can also result from medications, organ dysfunction, and sepsis even in the absence of malperfusion. Acidemia causes deleterious effects in almost every organ system, but it can also have positive effects, increasing localized blood flow and oxygen delivery, as well as providing protection against hypoxic cellular injury. The use of sodium bicarbonate to correct severe acidemia may be tempting to clinicians, but previous studies have failed to show improved patient outcomes following bicarbonate administration. Bicarbonate use is known to decrease vasomotor tone, decrease myocardial contractility, and induce intracellular acidosis. This suggests that mild to moderate acidemia does not require correction. Most recently, a randomized control trial found a survival benefit in a subgroup of critically ill patients with serum pH levels <7.2 with concomitant acute kidney injury. There is no known benefit of correcting serum pH levels ≥ 7.2, and sparse evidence supports bicarbonate use <7.2. If administered, bicarbonate is best given as a slow IV infusion in the setting of adequate ventilation and calcium replacement to mitigate its untoward effects.

Nonpharmacologic and Medication Minimization Strategies for the Prevention and Treatment of ICU Delirium: A Narrative Review.

Delirium is a multifactorial entity, and its understanding continues to evolve. Delirium has been associated with increased morbidity, mortality, length of stay, and cost for hospitalized patients, especially for patients in the intensive care unit (ICU). Recent literature on delirium focuses on specific pharmacologic risk factors and pharmacologic interventions to minimize course and severity of delirium. While medication management clearly plays a role in delirium management, there are a variety of nonpharmacologic interventions, pharmacologic minimization strategies, and protocols that have been recently described. A PubMed search was performed to review the evidence for nonpharmacologic management, pharmacologic minimization strategies, and prevention of delirium for patients in the ICU. Recent approaches were condensed into 10 actionable steps to manage delirium and minimize medications for ICU patients and are presented in this review.

Hemodynamic monitoring during liver transplantation: A state of the art review.

Orthotopic liver transplantation can be marked by significant hemodynamic instability requiring the use of a variety of hemodynamic monitors to aide in intraoperative management. Invasive blood pressure monitoring is essential, but the accuracy of peripheral readings in comparison to central measurements has been questioned. When discrepancies exist, central mean arterial pressure, usually measured at the femoral artery, is considered more indicative of adequate perfusion than those measured peripherally. The traditional pulmonary artery catheter is less frequently used due to its invasive nature and known limitations in measuring preload but still plays an important role in measuring cardiac output (CO) when required and in the management of portopulmonary hypertension. Pulse wave analysis is a newer technology that uses computer algorithms to calculate CO, stroke volume variation (SVV) and pulse pressure variation (PPV). Although SVV and PPV have been found to be accurate predicators of fluid responsiveness, CO measurements are not reliable during liver transplantation. Transesophageal echocardiography is finding an increasing role in the real-time monitoring of preload status, cardiac contractility and the diagnosis of a variety of pathologies. It is limited by the expertise required, limited transgastric views during key portions of the operation, the potential for esophageal varix rupture and difficulty in obtaining quantitative measures of CO in the absence of tricuspid regurgitation.