Introduction: Dynamic predictors of fluid responsiveness, namely systolic pressure variation, pulse pressure variation, stroke volume variation and pleth variability index have been shown to be useful to identify in advance patients who will respond to a fluid load by a significant increase in stroke volume and cardiac output. As a result, they are increasingly used to guide fluid therapy. Several randomized controlled trials have tested the ability of goal-directed fluid therapy (GDFT) based on dynamic parameters (GDFTdyn) to improve post-surgical outcome. These studies have yielded conflicting results. Therefore, we performed this meta-analysis to investigate whether the use of GDFTdyn is associated with a decrease in post-surgical morbidity. Methods: A systematic literature review, using MEDLINE, EMBASE, and The Cochrane Library databases through September 2013 was conducted. Data synthesis was obtained by using odds ratio (OR) and weighted mean difference (WMD) with 95% confidence interval (CI) by random-effects model. Results: In total, 14 studies met the inclusion criteria (961 participants). Post-operative morbidity was reduced by GDFTdyn (OR 0.51; CI 0.34 to 0.75; P <0.001). This effect was related to a significant reduction in infectious (OR 0.45; CI 0.27 to 0.74; P = 0.002), cardiovascular (OR 0.55; CI 0.36 to 0.82; P = 0.004) and abdominal (OR 0.56; CI 0.37 to 0.86; P = 0.008) complications. It was associated with a significant decrease in ICU length of stay (WMD -0.75 days; CI -1.37 to -0.12; P = 0.02). Conclusions: In surgical patients, we found that GDFTdyn decreased post-surgical morbidity and ICU length of stay. Because of the heterogeneity of studies analyzed, large prospective clinical trials would be useful to confirm our findings.

Previous meta-analyses suggest that perioperative goal-directed therapy (GDT) is useful to decrease postoperative morbidity. Most GDT studies analysed were done with pulmonary artery catheters, oesophageal Doppler and calibrated pulse contour methods. Uncalibrated pulse contour (uPC) techniques are an appealing alternative but their accuracy has been questioned. The effects of GDT on fluid management (volumes and volume variability) remain unclear. We performed a meta-analysis of randomized controlled trials investigating the effects of GDT with uPC methods on postoperative outcome. The primary endpoint was postoperative morbidity. Fluid volumes and fluid volume variability (standard deviation/mean) over the GDT period were also studied. Nineteen studies met the inclusion criteria (2159 patients). Postoperative morbidity was reduced with GDT (OR 0.46, 95% CI 0.30–0.70, P<0.001). The volume of colloids was higher [weighted mean difference (WMD) +345 ml, 95% CI 148–541 ml, P<0.001] and the volume of crystalloids was lower (WMD –429 ml, 95% CI –634 to –224 ml, P<0.01) in the GDT group than in the control group. However, the total volume of fluid (WMD –220 ml, 95% CI –590 to 150 ml, P=0.25) and the variability of fluid volume (34% vs 33%, P=0.98) were not affected by GDT. The use of GDT with uPC techniques was associated with a decrease in postoperative morbidity. It was not associated with an increase in total fluid volume nor with a decrease in fluid volume variability.

Enhanced recovery programmes (ERPs) are increasingly used to improve post-surgical recovery. However, compliance to various components of ERPs—a key determinant of success—remains sub-optimal. Emerging technologies have the potential to help patients and caregivers to improve compliance with ERPs. Preoperative physical condition, a major determinant of postoperative outcome, could be optimized with the use of text messages (SMS) or digital applications (Apps) designed to facilitate smoking cessation, modify physical activity, and better manage hypertension and diabetes. Several non-invasive haemodynamic monitoring techniques and decision support tools are now available to individualize perioperative fluid management, a key component of ERPs. Objective nociceptive assessment may help to rationalize the use of pain medications, including opioids. Wearable sensors designed to monitor cardio-respiratory function may help in the early detection of clinical deterioration during the postoperative recovery and to address ‘failure to rescue’. Activity trackers may be useful to monitor early mobilization, another major element of ERPs. Finally, electronic checklists have been developed to ensure that none of the above-mentioned ERP elements is omitted during the surgical journey. By optimizing compliance to the multiple components of ERPs, digital innovations, non-invasive techniques and wearable sensors have the potential to magnify the clinical and economic benefits of ERPs. Among the growing number of technical innovations, studies are needed to clarify which tools and solutions have real clinical value and are cost-effective.

Digital innovations are changing medicine, and hemodynamic monitoring will not be an exception. Five to ten years from now, we can envision a world where clinicians will learn hemodynamics with simulators and serious games, will monitor patients with wearable or implantable sensors in the hospital and after discharge, will use medical devices able to communicate and integrate the historical, clinical, physiologic and biological information necessary to predict adverse events, propose the most rationale therapy and ensure it is delivered properly. Considerable intellectual and financial investments are currently made to ensure some of these new ideas and products soon become a reality.