Predictive value of the respiratory exchange ratio for the occurrence of postoperative complications in laparoscopic surgery: a prospective and observational study

Bar, Stéphane; Santarelli, Dimitri; Broca, B. de; Abou-Arab, Osama; Leviel, Florent; Miclo, Matthieu; Dupont, Hervé; Guinot, Pierre-Grégoire; Lorne, Emmanuel

doi:10.1007/s10877-020-00544-5

Cited by 9 publications

(10 citation statements)

References 28 publications

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“…Bar and colleagues recently demonstrated the potential of RER to predict postoperative complications following both open abdominal high-risk and laparoscopic surgeries [1,8]. During high-risk open abdominal surgery, both lactate and RER were found to predict postoperative complications, with an AUC of 0.77 and 0.67, respectively [1].…”

Section: Discussionmentioning

confidence: 99%

“…Monitoring of the respiratory exchange ratio (RER), can reflect the presence of anaerobic metabolism in the mechanically ventilated patient [1,8]. This ratio increases in the presence of inadequate DO 2 for a given VO 2 and is computed using a standard anesthesia machine gas analyzer that continuously measures inspiratory and expiratory concentrations of O 2 and CO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Assessing the discriminative ability of the respiratory exchange ratio to detect hyperlactatemia during intermediate-to-high risk abdominal surgery

Karam

Desebbe²,

Coeckelenbergh

et al. 2022

BMC Anesthesiol

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Background A mismatch between oxygen delivery (DO2) and consumption (VO2) is associated with increased perioperative morbidity and mortality. Hyperlactatemia is often used as an early screening tool, but this non-continuous measurement requires intermittent arterial line sampling. Having a non-invasive tool to rapidly detect inadequate DO2 is of great clinical relevance. The respiratory exchange ratio (RER) can be easily measured in all intubated patients and has been shown to predict postoperative complications. We therefore aimed to assess the discriminative ability of the RER to detect an inadequate DO2 as reflected by hyperlactatemia in patients having intermediate-to-high risk abdominal surgery. Methods This historical cohort study included all consecutive patients who underwent intermediate-to-high risk surgery from January 1st, 2014, to April 30th, 2019 except those who did not have RER and/or arterial lactate measured. Blood lactate levels were measured routinely at the beginning and end of surgery and RER was calculated at the same moment as the blood gas sampling. The present study tested the hypothesis that RER measured at the end of surgery could detect hyperlactatemia at that time. A receiver operating characteristic (ROC) curve was constructed to assess if RER calculated at the end of the surgery could detect hyperlactatemia. The chosen RER threshold corresponded to the highest value of the sum of the specificity and the sensitivity (Youden Index). Results Among the 996 patients available in our study cohort, 941 were included and analyzed. The area under the ROC curve was 0.73 (95% CI: 0.70 to 0.76; p < 0.001), with a RER threshold of 0.75, allowing to discriminate a lactate > 1.5 mmol/L with a sensitivity of 87.5% and a specificity of 49.5%. Conclusion In mechanically ventilated patients undergoing intermediate to high-risk abdominal surgery, the RER had moderate discriminative abilities to detect hyperlactatemia. Increased values should prompt clinicians to investigate for the presence of hyperlactatemia and treat any potential causes of DO2/VO2 mismatch as suggested by the subsequent presence of hyperlactatemia.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Assessing the discriminative ability of the respiratory exchange ratio to detect hyperlactatemia during intermediate-to-high risk abdominal surgery

Karam

Desebbe²,

Coeckelenbergh

et al. 2022

BMC Anesthesiol

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“…Moreover, treatment of the shock corrected the RER [18]. We recently demonstrated that in major noncardiac surgery, the RER is predictive of hyperlactatemia and the occurrence of postoperative complications [19,20]. Thus, the RER may identify patients with VO 2 /DO 2 mismatch and who might bene t from maximization of DO 2 .…”

Section: Introductionmentioning

confidence: 98%

Individualized hemodynamic optimization guided by indirect measurement of respiratory exchange ratio in major surgery: study protocol for a randomized controlled trial (OPHIQUE study)

Bar

Boivin

Amine

et al. 2020

Preprint

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BackgroundObservational studies have suggested that a high respiratory exchange ratio (RER) is associated with the occurrence of postoperative complications. The study’s primary objective is to demonstrate that the incidence of postoperative complications is lower in an interventional group (patients monitored using a hemodynamic algorithm that incorporates the RER) than in a control group (treated according to standard practice).MethodsWe shall perform a prospective, multicenter, randomized, open-label, superiority trial of consecutive patients undergoing major non-cardiac surgery (i.e. abdominal, vascular and orthopedic surgery). The control group will be treated according to the current guidelines on standard hemodynamic care. The interventional group will be treated according an algorithm based on the RER. The primary outcome will be the occurrence of at least one complication within the 7 days following surgery. The secondary outcomes will be the length of hospital stay, the total number of complications per patient, 30-day mortality, the total intraoperative volume of fluids administered, the Sequential [sepsis-related] Organ Failure Assessment (SOFA) score, and laboratory data on postoperative days 1, 2 and 7. A total of 350 patients will be included.DiscussionIn the operating theater, the RER is potentially a continuously available, easy-to-read, indirect marker of tissue hypoperfusion and postoperative complications. If the RER predicts the occurrence of tissue hypoperfusion, it can help the physician to provide personalized hemodynamic management and limit the side effects related to excessive hemodynamic optimization (volume overload, vasoconstriction, etc.).Trial registrationClinicalTrials.gov identifier: NCT03852147. Registered on February 25th, 2019.

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“…Patients receiving a liver transplant are at high-risk of developing intraoperative tissue hypoxia, which may lead to postoperative complications. Quantifying any potential mismatch between oxygen delivery (DO 2 ) and oxygen consumption (VO 2 ) in this population is therefore of particular interest [ 1 , 2 ]. Various techniques have been used in an attempt to identify DO 2 /VO 2 mismatch during general anesthesia [ 3 ], most notably by measuring arterial lactate concentrations, mixed venous oxygen saturation (SvO 2 ) [ 4 ], and veno-arterial difference in the partial pressure of carbon dioxide (VAPCO 2 gap) [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

“…The respiratory exchange ratio (RER), on the other hand, may provide a more continuous indication of the presence of anaerobic metabolism in mechanically ventilated patients [ 1 , 2 ]. The RER is calculated using values derived from the standard anesthesia machine gas analyzer with the following formula: RER = (FeCO 2 - FiCO 2 ) / (FiO 2 - FeO 2 ).…”

Section: Introductionmentioning

confidence: 99%

Intraoperative measurement of the respiratory exchange ratio predicts postoperative complications after liver transplantation

Coeckelenbergh

Desebbe²,

Carrier

et al. 2022

BMC Anesthesiol

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Background During surgery, any mismatch between oxygen delivery (DO2) and consumption (VO2) can promote the development of postoperative complications. The respiratory exchange ratio (RER), defined as the ratio of carbon dioxide (CO2) production (VCO2) to VO2, may be a useful noninvasive tool for detecting inadequate DO2. The primary objective of this study was to test the hypothesis that RER measured during liver transplantation may predict postoperative morbidity. Secondary objectives were to assess the ability of other variables used to assess the DO2/VO2 relationship, including arterial lactate, mixed venous oxygen saturation, and veno-arterial difference in the partial pressure of carbon dioxide (VAPCO2gap), to predict postoperative complications. Methods This retrospective study included consecutive adult patients who underwent liver transplantation for end stage liver disease from June 27th, 2020, to September 5th, 2021. Patients with acute liver failure were excluded. All patients were routinely equipped with a pulmonary artery catheter. The primary analysis was a receiver operating characteristic (ROC) curve constructed to investigate the discriminative ability of the mean RER measured during surgery to predict postoperative complications. RER was calculated at five standardized time points during the surgery, at the same time as measurement of blood lactate levels and arterial and mixed venous blood gases, which were compared as a secondary analysis. Results Of the 115 patients included, 57 developed at least one postoperative complication. The mean RER (median [25–75] percentiles) during surgery was significantly higher in patients with complications than in those without (1.04[0.96–1.12] vs 0.88[0.84–0.94]; p < 0.001). The area under the ROC curve was 0.87 (95%CI: 0.80–0.93; p < 0.001) with a RER value (Youden index) of 0.92 giving a sensitivity of 91% and a specificity of 74% for predicting the occurrence of postoperative complications. The RER outperformed all other measured variables assessing the DO2/VO2 relationship (arterial lactate, SvO2, and VAPCO2gap) in predicting postoperative complications. Conclusion During liver transplantation, the RER can reliably predict postoperative complications. Implementing this measure intraoperatively may provide a warning for physicians of impending complications and justify more aggressive optimization of oxygen delivery. Further studies are required to determine whether correcting the RER is feasible and could reduce the incidence of complications.

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Predictive value of the respiratory exchange ratio for the occurrence of postoperative complications in laparoscopic surgery: a prospective and observational study

Cited by 9 publications

References 28 publications

Assessing the discriminative ability of the respiratory exchange ratio to detect hyperlactatemia during intermediate-to-high risk abdominal surgery

Assessing the discriminative ability of the respiratory exchange ratio to detect hyperlactatemia during intermediate-to-high risk abdominal surgery

Individualized hemodynamic optimization guided by indirect measurement of respiratory exchange ratio in major surgery: study protocol for a randomized controlled trial (OPHIQUE study)

Intraoperative measurement of the respiratory exchange ratio predicts postoperative complications after liver transplantation

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