[Pulse pressure variation guided fluid therapy during kidney transplantation: a randomized controlled trial]

Assessment of fluid responsiveness after tidal volume challenge in renal transplant recipients: a nonrandomized prospective interventional study

Background

When applying lung-protective ventilation, fluid responsiveness cannot be predicted by pulse pressure variation (PPV) or stroke volume variation (SVV). Functional hemodynamic testing may help address this limitation. This study examined whether changes in dynamic indices such as PPV and SVV, induced by tidal volume challenge (TVC), can reliably predict fluid responsiveness in patients undergoing renal transplantation who receive lung-protective ventilation.

Methods

This nonrandomized interventional study included renal transplant recipients with end-stage renal disease. Patients received ventilation with a 6 mL/kg tidal volume (TV), and the FloTrac system was attached for continuous hemodynamic monitoring. Participants were classified as responders or nonresponders based on whether fluid challenge increased the stroke volume index by more than 10%.

Results

The analysis included 36 patients, of whom 19 (52.8%) were responders and 17 (47.2%) were nonresponders. Among responders, the mean ΔPPV6-8 (calculated as PPV at a TV of 8 mL/kg predicted body weight [PBW] minus that at 6 mL/kg PBW) was 3.32±0.75 and ΔSVV6-8 was 2.58±0.77, compared to 0.82±0.53 and 0.70±0.92 for nonresponders, respectively. ΔPPV6-8 exhibited an area under the curve (AUC) of 0.97 (95% confidence interval [CI], 0.93-1.00; P≤0.001), with an optimal cutoff value of 1.5, sensitivity of 94.7%, and specificity of 94.1%. ΔSVV6-8 displayed an AUC of 0.93 (95% CI, 0.84-1.00; P≤0.001) at the same cutoff value of 1.5, with a sensitivity of 94.7% and a specificity of 76.5%.

Conclusions

TVC-induced changes in PPV and SVV are predictive of fluid responsiveness in renal transplant recipients who receive intraoperative lung-protective ventilation.

Enhanced recovery after surgery recommendations for renal transplantation: guidelines

BACKGROUND

Enhanced Recovery After Surgery (ERAS) protocols are now widely practiced in major surgery, improving postsurgical outcomes. Uptake of these programmes have been slow in kidney transplantation due to challenges in evaluating their safety and efficacy in this high-risk cohort. To date, there are no unified guidance and protocols specific to ERAS in kidney transplantation surgery. This paper aims to summarise current evidence in the literature and develop ERAS protocol recommendations for kidney transplantation recipients.

METHODS

PubMed, Cochrane, Embase and Medline databases were screened for studies relevant to ERAS protocols in kidney transplantation, up to August 2021. A secondary search was repeated for each ERAS recommendation to explore the specific evidence base available for each section of the protocol. Randomised controlled trials, case-control and cohort studies were included. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) framework was used to evaluate the quality of evidence available and recommendations.

RESULTS

We identified six eligible studies with a total of 1225 participants. All studies found a reduction in length of hospital stay without affecting readmission rates. The evidence behind specific pre-operative, intra-operative and post-operative interventions included in current ERAS protocols are reviewed and discussed.

CONCLUSION

Compared to other surgical specialties, the evidence base for ERAS in kidney transplantation remains lacking, with further room for research and development. However, significant improvements to patient outcomes are already possible with application of the currently available evidence. This has shown that ERAS in kidney transplantation surgery is safe and feasible, with improved postoperative outcomes.

Goal-directed haemodynamic therapy during general anaesthesia for noncardiac surgery: a systematic review and meta-analysis

BACKGROUND

During general anaesthesia for noncardiac surgery, there remain knowledge gaps regarding the effect of goal-directed haemodynamic therapy on patient-centred outcomes.

METHODS

Included clinical trials investigated goal-directed haemodynamic therapy during general anaesthesia in adults undergoing noncardiac surgery and reported at least one patient-centred postoperative outcome. PubMed and Embase were searched for relevant articles on March 8, 2021. Two investigators performed abstract screening, full-text review, data extraction, and bias assessment. The primary outcomes were mortality and hospital length of stay, whereas 15 postoperative complications were included based on availability. From a main pool of comparable trials, meta-analyses were performed on trials with homogenous outcome definitions. Certainty of evidence was evaluated using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE).

RESULTS

The main pool consisted of 76 trials with intermediate risk of bias for most outcomes. Overall, goal-directed haemodynamic therapy might reduce mortality (odds ratio=0.84; 95% confidence interval [CI], 0.64 to 1.09) and shorten length of stay (mean difference=-0.72 days; 95% CI, -1.10 to -0.35) but with low certainty in the evidence. For both outcomes, larger effects favouring goal-directed haemodynamic therapy were seen in abdominal surgery, very high-risk surgery, and using targets based on preload variation by the respiratory cycle. However, formal tests for subgroup differences were not statistically significant. Goal-directed haemodynamic therapy decreased risk of several postoperative outcomes, but only infectious outcomes and anastomotic leakage reached moderate certainty of evidence.

CONCLUSIONS

Goal-directed haemodynamic therapy during general anaesthesia might decrease mortality, hospital length of stay, and several postoperative complications. Only infectious postoperative complications and anastomotic leakage reached moderate certainty in the evidence.

The effect of pulse pressure variation compared with central venous pressure on intraoperative fluid management during kidney transplant surgery: a randomized controlled trial

BACKGROUND

Traditionally, fluid administration during kidney transplant surgery is guided by central venous pressure (CVP) despite its limited reliability as a parameter for assessing intravascular fluid volume, particularly in patients with cardiovascular diseases. The recommended goals at graft reperfusion are a mean arterial pressure of 90 mm Hg and a CVP of 12-14 mm Hg. This approach may increase the risk of significant adverse effects due to volume overload. Perioperative fluid therapy guided by dynamic indices of fluid responsiveness has been shown to optimize intravascular volume and prevent complications associated with overzealous administration of fluids in major abdominal surgeries. We hypothesized that pulse pressure variation (PPV)-guided fluid administration would result in better optimization of intravascular fluid volume compared with a CVP-guided strategy during kidney transplant surgery.

METHODS

In this single-centre randomized double blinded trial, 77 end-stage renal disease patients, who underwent kidney transplant surgery under general anesthesia with epidural analgesia, were randomized to receive either CVP-guided (n = 35) or PPV-guided (n = 35) fluid therapy using predefined hemodynamic endpoints. The primary outcome was the total volume of intraoperative fluids administered. Secondary outcomes were intraoperative hemodynamic changes, serum lactate levels, serum creatinine, need for dialysis within the first week, creatinine elimination ratio, and incidence of immediate and delayed graft dysfunction.

RESULTS

Results were analyzed for 70 patients. Eighty percent of the patients underwent living-related donor allograft kidney transplant. Operative variables related to donor characteristics, duration of surgery, graft cold ischemia time, and blood loss were comparable in both groups. The mean (standard deviation) volume of intravenous fluids administered intraoperatively was 1,346 (337) mL in the PPV-guided group vs 1,901 (379) mL in the CVP-guided group (difference in means, 556 mL; 95% confidence interval, 385 to 727; P = 0.001). There were no significant differences in secondary outcomes between the two groups.

CONCLUSION

Pulse pressure variation -guided fluid administration significantly decreased the total volume of crystalloids compared with CVP-guided fluid therapy during the intraoperative period in patients who underwent kidney transplant surgery. Nevertheless, our study was underpowered to detect differences in secondary outcomes.

TRIAL REGISTRATION

www.ctri.nic.in (CTRI/2018/01/011638); registered 31 January 2018.