Influence of early goal-directed therapy using arterial waveform analysis on major complications after high-risk abdominal surgery: study protocol for a multicenter randomized controlled superiority trial

Abstract

Background: Early goal-directed therapy refers to the use of predefined hemodynamic goals to optimize tissue oxygen delivery in critically ill patients. Its application in high-risk abdominal surgery is, however, hindered by safety concerns and practical limitations of perioperative hemodynamic monitoring. Arterial waveform analysis provides an easy, minimally invasive alternative to conventional monitoring techniques, and could be valuable in early goal-directed strategies. We therefore investigate the effects of early goal-directed therapy using arterial waveform analysis on complications, quality of life and healthcare costs after high-risk abdominal surgery.

Methods/design: In this multicenter, randomized, controlled superiority trial, 542 patients scheduled for elective, high-risk abdominal surgery will be included. Patients are allocated to standard care (control group) or early goal-directed therapy (intervention group) using a randomization procedure stratified by center and type of surgery. In the control group, standard perioperative hemodynamic monitoring is applied. In the intervention group, early goal-directed therapy is added to standard care, based on continuous monitoring of cardiac output with arterial waveform analysis. A treatment algorithm is used as guidance for fluid and inotropic therapy to maintain cardiac output above a preset, age-dependent target value. The primary outcome measure is a combined endpoint of major complications in the first 30 days after the operation, including mortality. Secondary endpoints are length of stay in the hospital, length of stay in the intensive care or post-anesthesia care unit, the number of minor complications, quality of life, cost-effectiveness and one-year mortality and morbidity.

Discussion: Before the start of the study, hemodynamic optimization by early goal-directed therapy with arterial waveform analysis had only been investigated in small, single-center studies, including minor complications as primary endpoint. Moreover, these studies did not include quality of life, healthcare costs, and long-term outcome in their analysis. As a result, the definitive role of arterial waveform analysis in the perioperative hemodynamic assessment and care for high-risk surgical patients is unknown, which gave rise to the present trial. Patient inclusion started in May 2012 and is expected to end in 2016.

Trial registration: This trial was registered in the Dutch Trial Register (registration number NTR3380) on 3 April 2012.

Figure 1

EGDT algorithm. ⁽¹⁾target value depends on age: age < 60 years: target CI ≥ 2.8 l/min/m²; age between 60 and 75 years: target CI ≥ 2.6 l/min/m²; or age > 75 years: target CI ≥ 2.4 l/min/m². ⁽²⁾”no” in the presence of spontaneous breathing activity, tidal volume < 8 ml/kg, or breathing frequency > 16/min. ⁽³⁾CI increases: repeat FC. If not: increase inotropic support. CI = Cardiac Index, FC = Fluid Challenge, PLR = Passive Leg Raising, SVV = Stroke Volume Variation, Tidal volumes are in ml/kg ideal body weight (IBW); IBW is calculated as 22 × L² (L = length in meters).

Figure 2

Passive leg raising (PLR) test. The patient is transferred to the PLR position, in which the legs are lifted at an angle of 45° for 120 seconds. This should be performed by pivoting the entire bed.