Bench-to-bedside review: Functional hemodynamics during surgery - should it be used for all high-risk cases?

Abstract

The administration of a fluid bolus is done frequently in the perioperative period to increase the cardiac output. Yet fluid loading fails to increase the cardiac output in more than 50% of critically ill and surgical patients. The assessment of fluid responsiveness (the slope of the left ventricular function curve) prior to fluid administration may thus not only help in detecting patients in need of fluids but may also prevent unnecessary and harmful fluid overload. Unfortunately, commonly used hemodynamic parameters, including the cardiac output itself, are poor predictors of fluid responsiveness, which is best assessed by functional hemodynamic parameters. These dynamic parameters reflect the response of cardiac output to a preload-modifying maneuver (for example, a mechanical breath or passive leg-raising), thus providing information about fluid responsiveness without the actual administration of fluids. All dynamic parameters, which include the respiratory variations in systolic blood pressure, pulse pressure, stroke volume and plethysmographic waveform, have been repeatedly shown to be superior to commonly used static preload parameters in predicting the response to fluid loading. Within their respective limitations, functional hemodynamic parameters should be used to guide fluid therapy as part of or independently of goal-directed therapy strategies in the perioperative period.

Goal-Directed Fluid Therapy Using Stroke Volume Variation for Resuscitation after Low Central Venous Pressure-Assisted Liver Resection: A Randomized Clinical Trial

“…The ultimate goal of these techniques is to achieve optimal oxygen delivery while avoiding the deleterious complications associated with over- and under-resuscitation. [22, 23] First described decades ago, [22-24] this concept has gained increased attention in the recent years and it has been suggested that it could improve various perioperative outcomes in selected patients. Randomized trials, however, have shown mixed results.…”

Fluid management and goal-directed therapy as an adjunct to Enhanced Recovery After Surgery (ERAS)

“…48 The dynamic variables arise from heart-lung interactions during positive pressure variation; therefore, any change in tidal volume and /or intrathoracic pressure will affect the interaction. 49 A tidal volume \ 8 mLÁkg -1 decreases this interaction and, thus, decreases the negative predictive value of PPV, SVV, or SPV. In other words, a patient may have a low PPV but may actually be volume responsive.…”

Middle cerebral artery blood flow velocity during beach chair position for shoulder surgery under general anesthesia

“…Taken together, these data confirmed that hypotension after beach chair position is frequent and required important fluid and vasopressor administration. This must be interpreted with the knowledge of the critical role of perioperative fluid administration and hemodynamic optimization in postoperative outcome [15,16].…”