Effect of fluid strategy on stroke volume, cardiac output, and fluid responsiveness in adult patients undergoing major abdominal surgery: a sub-study of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial

Fluid responsiveness and hypotension in patients undergoing propofol-based sedation for colonoscopy following bowel preparation: a prospective cohort study

PURPOSE

Fasting and bowel preparation may deplete intravascular volume in patients undergoing colonoscopy. Nevertheless, rigorous demonstration of volume depletion and assessment of clinical consequences is lacking. We designed this study to explore the relationship between intravascular volume status and intraprocedural hypotension and to compare transthoracic echocardiography (TTE) and the ClearSight™ (Edwards Lifesciences, Irvine, CA, USA) noninvasive cardiac output monitor to measure intravascular volume status.

METHODS

We recruited adult patients undergoing elective colonoscopy following bowel preparation at the Royal Melbourne Hospital. We assessed the volume status preprocedure by taking TTE and ClearSight measurements in patients in the semirecumbent position and following passive leg raising. Patients received propofol-based sedation, and significant intraprocedural hypotension was defined as a mean arterial pressure (MAP) < 60 mm Hg. The primary outcome was the occurrence of intravascular volume depletion as assessed by a positive result in a passive leg raise test on TTE (a 15% increase in the subaortic velocity time integral).

RESULTS

Ninety-nine patients completed the study. The primary outcome was recorded in 29 of the 90 patients with adequate TTE images (32%; 95% confidence interval, 23 to 43). There was inadequate agreement between average TTE and ClearSight measurements of stroke volume at baseline or after passive leg raising. More patients experienced significant intraprocedural hypotension in the fluid-responsive group (48%) than in the normovolemic group (21%).

CONCLUSION

Patients undergoing elective colonoscopy after bowel preparation were often fluid responsive. These patients were more likely to have significant intraprocedural hypotension than patients who were volume replete. Transthoracic echocardiography assessment of volume status cannot be readily replaced by ClearSight monitoring.

STUDY REGISTRATION

ANZCTR.org.au ( ACTRN12616000614493 ); first registered 11 May 2016.

The effect of restrictive compared to liberal intravenous fluid volume on hypotension in adults undergoing major abdominal surgery

In a cardiac output (CO) sub-study of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial, it was shown that restrictive fluid management was associated with lower cardiac index at the end of surgery. However, the association of the fluid protocol with intraoperative blood pressure was less clear. This paper primarily compares rates of hypotension between the two fluid regimens. The haemodynamic effects of these protocols may increase our understanding of perioperative fluid prescription. Using a data set of arterial pressure and cardiac output measurements, this observational cohort study primarily compares intraoperative hypotension rates defined by a mean arterial pressure < 65 mmHg between liberal and restrictive fluid protocols. Secondary analyses explore predictors of invasive mean arterial pressure and doppler-derived cardiac output, including fluid volume regimens and surgical duration. 105 patients had a combined total of 835 haemodynamic data capture events from the beginning to the end of the surgery. Here we report that a restrictive regimen is not associated with a greater proportion of participants who experience at least one episode of hypotension than the liberal regimen 64.1% vs. 61.5% (mean difference 2.6%, 95% CI - 15.9% to 21%, p = 0.78). Duration of surgery was associated with an increased risk of hypotension (OR 1.05, 1 to 1.1, p = 0.038). A fluid restriction protocol compared to liberal fluid administration is not associated with lower blood pressure.

Respiratory Exchange Ratio guided management in high-risk noncardiac surgery: The OPHIQUE multicentre randomised controlled trial

BACKGROUND

There is a need to develop non-invasive markers to identify the occurrence of anaerobic metabolism in high-risk surgery. Our objective was to demonstrate that a goal-directed therapy algorithm incorporating the respiratory exchange ratio (ratio between CO2 production and O2 consumption) can reduce postoperative complications.

METHODS

We conducted a randomized, multicenter, controlled clinical trial in four university medical centers and one non-university hospital from December 26, 2018, to September 9, 2021. 350 patients with a high risk of postoperative complications undergoing high-risk noncardiac surgery lasting 2 h or longer under general anesthesia were enrolled. The control group was treated according to current hemodynamic guidelines. The interventional group was treated according to an algorithm based on the measurement of the respiratory exchange ratio. The primary outcome was a composite of major complications or death within seven days of surgery. The secondary outcomes were the length of hospital stay, 30-day mortality, and the total intraoperative volume of fluids administered.

RESULTS

The primary outcome occurred for 78 patients (45.6%) in the interventional group and 83 patients (48.8%) in the control group (relative risk: 0.93, 95% confidence interval [CI]: 0.75-1.17; p = 0.55). There were no clinically relevant differences between the two groups for secondary outcomes.

CONCLUSIONS

In high-risk surgery, a goal-directed therapy algorithm integrating the measurement of the respiratory-exchange ratio did not reduce a composite outcome of major postoperative complications or death within seven days after surgery compared to routine care.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03852147.

The effect of intraoperative goal-directed fluid therapy combined with enhanced recovery after surgery program on postoperative complications in elderly patients undergoing thoracoscopic pulmonary resection: a prospective randomized controlled study

BACKGROUND

To investigate the effect of intraoperative goal-directed fluid therapy (GDFT) combined with enhanced recovery after surgery (ERAS) program on postoperative complications in elderly patients undergoing thoracoscopic pulmonary resection.

METHODS

Patients, more than 60 years old, undergoing thoracoscopic pulmonary resection for non-small cell lung cancer were randomly divided into GDFT group and restrictive fluid therapy (RFT) group. ERAS program was implemented in all patients. In GDFT group, the intraoperative fluid management was guided by stroke volume variation (SVV), cardiac index (CI), and mean arterial pressure (MAP) and maintained the SVV < 13%, CI > 2.5 L/min/m², and MAP > 65 mmHg. In RFT group, fluid maintenance with 2 ml/kg/h of balanced crystalloid solution, norepinephrine was used to maintain MAP > 65 mmHg. The incidence of postoperative acute kidney injury (AKI) and pulmonary and cardiac complications was compared.

RESULTS

Two-hundred seventy-six patients were enrolled and randomly divided into two groups (138 in each group). Compared to RFT group, the total intraoperative infusion volume, colloids infusion volume, and urine output were more; the dosage of norepinephrine was lower in GDFT group. Although there were no significant differences of postoperative AKI (GDFT vs RFT; 4.3% vs 8%; P = 0.317) and composite postoperative complications (GDFT vs RFT; 66 vs 70) between groups, but the postoperative increase degree of serum creatinine was lower in GDFT group than that in RFT group (GDFT vs RFT; 91.9 ± 25.2 μmol/L vs 97.1 ± 17.6 μmol/L; P = 0.048).

CONCLUSIONS

Under ERAS program, there was no significant difference of AKI incidence between GDFT and RFT in elderly patients undergoing thoracoscopic pulmonary resection. But postoperative increase degree of serum creatinine was lower in GDFT group.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov, NCT04302467 on 26 February 2020.

Post-operative outcomes of intra-operative restrictive and conventional fluid management in laparoscopic colorectal cancer surgery

Context

Intra-operative fluid management has been shown to significantly alter a patient's clinical condition in peri-operative care. Studies in the literature that investigated the effects of different amounts of intra-operative fluids on outcomes reported conflicting results.

Aims

To compare the post-operative results of intra-operative restrictive and conventional fluid administrations in laparoscopic colorectal cancer surgery.

Settings and Design

All patients with ASA I, II and III, and those who had undergone laparoscopic colorectal cancer surgery were included. It was a retrospective, cohort study.

Subjects and Methods

A review of laparoscopic colorectal cancer surgeries performed by the same fellow-trained colorectal surgeon with different anaesthesiologists between 1 January, 2018 and 30 November, 2021.

Results

In total 80 patients were analysed; 2 patients were excluded, 28 patients were in restrictive (Group R) and 50 patients were in the conventional (Group C) group. The median age of all patients was 63 years and 74% were male. The median (interquartile ranges 25 to 75) intra-operative fluid administration was significantly different between groups; 3 ml/kg/h in Group R, and 7.2 ml/kg/h in Group C. (P < 0.001) Patients in Group C had significantly high post-operative intensive care unit admission (P < 0.05), and hospital length of stay (P = 0.005) compared to Group R.

Conclusions

Intra-operative fluid management was significantly associated with post-operative hospital length of stay and intensive care unit admission. Excessive intra-operative fluid management should be avoided in daily practice to improve the outcomes of laparoscopic colorectal cancer surgery.