A randomised controlled outcome study evaluating the effect of peri-
operative haemodynamic optimisation on mortality, morbidity and length of
hospital stay in Whipple’s operations
ABSTRACT
Background
Patients undergoing Whipple’s surgery perhaps represent the ultimate discriminator in
terms of the efficacy of goal-directed therapy (GDT). We aimed to compare the outcomes of
patients with a perioperative GDT algorithm using ProAQT technology with those receiving
standard care.
Methods
100 patients listed for Whipple’s surgery were randomised to three groups. Group one
received standard intra-operative care without GDT. Group two had their pre-operative
cardiac index (CI) maintained intra-operatively. Group three had their pre-operative CI
maintained intra-operatively, with a post-operative oxygen delivery index (DO2I) target of
600ml/min/m2 for 8 hours. In the GDT groups patients if stroke volume variation (SVV) was
>12.5 per cent, then a bolus of Gelofusine® was administered. Post-induction MAP was maintained
≥60mmHg and systemic vascular resistance index (SVRI) >1000 with phenylephrine infusion.
If CI fell by 10 per cent from the baseline value, a dopexamine infusion was commenced. Length of
hospital stay was the primary endpoint and complication rate the secondary endpoint.
Results
Of the 100 patients recruited, 73 subsequently underwent Whipple’s surgery. Mean P-
POSSUM score was similar between groups one to three, but predicted morbidity (%) was
not (24.9 ±13.5 vs 33.1 ±18.7 vs 41.1 ±20.3; p=0.018). When comparing median length of
hospital stay (11 days [9.5-16.5] vs 10 days [9.5-15.5] vs 13 days [10-25]) a significant
difference could not be demonstrated (p=0.265). There was no statistical difference
between the three groups when comparing volumes of intravenous fluid administered or
postoperative complications.
Conclusions
This study indicates that implementing a GDT algorithm guided by a minimally invasive
cardiac output monitor was not associated with a decrease in length of stay or the incidence
of overall complications in patients undergoing pancreaticoduodenectomy. It is possible
that these findings may have been confounded by the allocation of patients with higher
predicted morbidity to the GDT groups despite randomisation.
INTRODUCTION
High risk surgery in a high risk patient carries high morbidity and mortality rates. Pancreaticoduodenectomy (Whipples procedure) is usually performed for pancreatic cancer
in patients with multiple co-morbidities. Mortality rates range from 3-20 per cent, and major
complications are not infrequent.
All patients undergoing major (high risk) surgical procedures are at risk from inadequate intra-operative oxygen delivery leading to a build-up of oxygen debt which needs to be re-paid in the post-operative period. Shoemaker et al considered that the pre-operative oxygen consumption (VO2) could be used as a baseline for quantifying this debt using invasive monitoring together with repeated intra-operative and post-operative VO2, DO2 and cardiac output measurements. If the debt exceeded a specific value, this led to complications and death as well as the detrimental effects of both hypovolaemia or else fluid overload. [1,2] At present, there is a substantial evidence base to provide guidance on peri-operative fluid therapy and haemodynamic optimisation, although much of it is conflicting. The challenge is to provide the right amount of the right type of fluid at the right time. [3,4]
Fluid optimisation underpins principles outlined in the ‘Enhanced Recovery Programme’, which refers specifically to colorectal patients and recommendations made in the GIFTASUP (Guidelines on Intravenous Fluid Therapy for Adult Surgical Patients). In addition to fluid optimisation, a number of authors have proposed that goal directed therapy – measuring and targeting supranormal oxygen delivery – can improve outcome in high risk surgical patients. [4] The normal physiological response to surgery includes an increased cardiac output, and an increased oxygen delivery. Shoemaker et al demonstrated that those who were unable to increase their peri-operative oxygen delivery in response to intra-operative oxygen debt were at increased risk of complications. The median haemodynamic parameters of those surviving surgery included CI >4.5 l/min/m2, DO2I >600ml/min/m2 and VO2 of >170ml/min/m2. Shoemaker demonstrated that augmenting these parameters with fluids and inotropes led to a substantial decrease in mortality. [5,6]
Optimisation and maintenance of normal DO2 during surgery is readily achieved by maintenance of haemoglobin levels and cardiac output. Technologies currently available for measuring cardiac output peri-operatively include the pulmonary-artery catheters (PAC), PiCCO™ /ProAQT, esophageal dopler monitoring (EDM), LiDCO™ /PulseCO, Vigileo™ /Flotrac™, ultrasonic cardiac output monitor (USCOM) and noninvasive cardiac output monitoring (NICOM). All methods attempt to ensure adequate tissue oxygen delivery. However, practice which targets central venous pressure (CVP) to guide fluid therapy often does not achieve these aims. [7]
The aim of this study was to determine the effect of optimisation and goal directed therapy applied in a reproducible, minimally invasive and resource-efficient fashion through the peri-operative course. Measures of outcome would include length of hospita