High-risk Abdominal Surgery Research Articles

Comparison of pulse pressure and stroke volume variations measured by three monitors in high-risk surgical patients

IntroductionDynamic indices of fluid responsiveness (FR) such as pulse pressure variation (PPV) and stroke volume variation (SVV) differ among hemodynamic monitors, which use proprietary algorithms, and vary even over a short period of time. We aimed to compare the baseline values, fluctuation and predictive value for FR of PPV and SVV measured by three minimally invasive monitors. Patients and methodsTwenty patients undergoing high-risk abdominal surgery were included and 45 fluid challenges were analysed. The patients were simultaneously monitored using Carescape B650, LiDCO Rapid and FloTrac/Vigileo system. Cardiac output (CO), PPV and SVV were recorded before and after the fluid challenge of 500ml of balanced crystalloid solution. An increase in CO ≥ 15 % defined fluid responders. Concurrently recorded arterial waveform was used for offline calculation of PPV. ResultsMean baseline values of the indices ranged between 8.6% and 13.4%. LiDCO showed higher fluctuation of indices compared to the other monitors. Area under the receiver operating characteristic curve (AUROC) ranged from 0.71 to 0.76 with optimal cut-off value between 7.5% and 13.9%. AUROC increased for all indices when FR was defined as an increase in stroke volume. Furthermore, a decrease in PPV or SVV after fluid challenge (ΔPPV, ΔSVV) proved a better marker of FR (AUROC 0.82 – 0.93) than baseline values with a uniform threshold of approximately -3%. ConclusionsAlthough a significant range of baselines variations and optimal cut-off values was observed, the predictive value of PPV and SVV from all the monitors was only moderate and comparable. Nevertheless, ΔPPV and ΔSVV appear to be a reliable and device-independent markers of FR.

Assisted Fluid Management and Sublingual Microvascular Flow During High-Risk Abdominal Surgery: A Randomized Controlled Trial.

Implementation of goal-directed fluid therapy (GDFT) protocols remains low. Protocol compliance among anesthesiologists tends to be suboptimal owing to the high workload and the attention required for implementation. The assisted fluid management (AFM) system is a novel decision support tool designed to help clinicians apply GDFT protocols. This system predicts fluid responsiveness better than anesthesia practitioners do and achieves higher stroke volume (SV) and cardiac index values during surgery. We tested the hypothesis that an AFM-guided GDFT strategy would also be associated with better sublingual microvascular flow compared to a standard GDFT strategy. This bicenter, parallel, 2-arm, prospective, randomized controlled, patient and assessor-blinded, superiority study considered for inclusion all consecutive patients undergoing high-risk abdominal surgery who required an arterial catheter and uncalibrated SV monitoring. Patients having standard GDFT received manual titration of fluid challenges to optimize SV while patients having an AFM-guided GDFT strategy received fluid challenges based on recommendations from the AFM software. In all patients, fluid challenges were standardized and titrated per 250 mL and vasopressors were administered to maintain a mean arterial pressure >70 mm Hg. The primary outcome (average of each patient's intraoperative microvascular flow index (MFI) across 4 intraoperative time points) was analyzed using a Mann-Whitney U test and the treatment effect was estimated with a median difference between groups with a 95% confidence interval estimated using the bootstrap percentile method (with 1000 replications). Secondary outcomes included SV, cardiac index, total amount of fluid, other microcirculatory variables, and postoperative lactate. A total of 86 patients were enrolled over a 7-month period. The primary outcome was significantly higher in patients with AFM (median [Q1-Q3]: 2.89 [2.84-2.94]) versus those having standard GDFT (2.59 [2.38-2.78] points, median difference 0.30; 95% confidence interval [CI], 0.19-0.49; P < .001). Cardiac index and SVI were higher (3.2 ± 0.5 vs 2.7 ± 0.7 l.min-1.m-2; P = .001 and 42 [35-47] vs 36 [32-43] mL.m-2; P = .018) and arterial lactate concentration was lower at the end of the surgery in patients having AFM-guided GDFT (2.1 [1.5-3.1] vs 2.9 [2.1-3.9] mmol.L-1; P = .026) than patients having standard GDFT strategy. Patients having AFM received a higher fluid volume but 3 times less norepinephrine than those receiving standard GDFT (P < .001). Use of an AFM-guided GDFT strategy resulted in higher sublingual microvascular flow during surgery compared to use of a standard GDFT strategy. Future trials are necessary to make conclusive recommendations that will change clinical practice.

Peripheral perfusion index stratifies risk in patients with intraoperative anemia: A multicentre cohort study

Study objectiveEvidence for red blood cell (RBC) transfusion thresholds in the intraoperative setting is limited, and current perioperative recommendations may not correspond with individual intraoperative physiological demands. Hemodynamics relevant for the decision to transfuse may include peripheral perfusion index (PPI). The objective of this prospective study was to assess the associations of PPI and hemoglobin levels with the risk of postoperative morbidity and mortality. DesignMulticenter cohort study. SettingBispebjerg and Hvidovre University Hospitals, Copenhagen, Denmark. PatientsWe included 741 patients who underwent acute high risk abdominal surgery or hip fracture surgery. InterventionsNo interventions were carried out. MeasurementsPrincipal values collected included measurements of peripheral perfusion index and hemoglobin values. MethodsThe study was conducted using prospectively obtained data on adults who underwent emergency high-risk surgery. Subjects were categorized into high vs. low subgroups stratified by pre-defined PPI levels (PPI: > 1.5 vs. < 1.5) and Hb levels (Hb: > 9.7 g/dL vs. < 9.7 g/dL). The study assessed mortality and severe postoperative complications within 90 days. Main resultsWe included 741 patients. 90-day mortality was 21% (n = 154), frequency of severe postoperative complications was 31% (n = 231).Patients with both low PPI and low Hb had the highest adjusted odds ratio for both 90-day severe postoperative complications (2.95, [1.62–5.45]) and 90-day mortality (3.13, [1.45–7.11]).A comparison of patients with low PPI and low Hb to those with high PPI and low Hb detected significantly higher 90-day mortality risk in the low PPI and low Hb group (OR 8.6, [1.57–162.10]). ConclusionHigh PPI in acute surgical patients who also presents with anemia was associated with a significantly better outcome when compared with patients with both low PPI and anemia. PPI should therefore be further investigated as a potential parameter to guide intraoperative RBC transfusion therapy.

Pulse pressure variation guided goal-direct fluid therapy decreases postoperative complications in elderly patients undergoing laparoscopic radical resection of colorectal cancer: a randomized controlled trial

ObjectiveThe use of goal-directed fluid therapy (GDFT) has been shown to reduce complications and improve prognosis in high-risk abdominal surgery patients. However, the utilization of pulse pressure variation (PPV) guided GDFT in laparoscopic surgery remains a subject of debate. We hypothesized that utilizing PPV guidance for GDFT would optimize short-term prognosis in elderly patients undergoing laparoscopic radical resection for colorectal cancer compared to conventional fluid therapy.MethodsElderly patients undergoing laparoscopic radical resection of colorectal cancer were randomized to receive either PPV guided GDFT or conventional fluid therapy and explore whether PPV guided GDFT can optimize the short-term prognosis of elderly patients undergoing laparoscopic radical resection of colorectal cancer compared with conventional fluid therapy.ResultsThe incidence of complications was significantly lower in the PPV group compared to the control group (32.8% vs. 57.1%, P = .009). Additionally, the PPV group had a lower occurrence of gastrointestinal dysfunction (19.0% vs. 39.3%, P = .017) and postoperative pneumonia (8.6% vs. 23.2%, P = .033) than the control group.ConclusionUtilizing PPV as a monitoring index for GDFT can improve short-term prognosis in elderly patients undergoing laparoscopic radical resection of colorectal cancer.Registration numberChiCTR2300067361; date of registration: January 5, 2023.

Can perioperative pCO2 gaps predict complications in patients undergoing major elective abdominal surgery randomized to goal-directed therapy or standard care? A secondary analysis

The difference between venous and arterial carbon dioxide pressure (pCO2 gap), has been used as a diagnostic and prognostic tool. We aimed to assess whether perioperative pCO2 gaps can predict postoperative complications. This was a secondary analysis of a multicenter RCT comparing goal-directed therapy (GDT) to standard care in which 464 patients undergoing high-risk elective abdominal surgery were included. Arterial and central venous blood samples were simultaneously obtained at four time points: after induction, at the end of surgery, at PACU/ICU admission, and PACU/ICU discharge. Complications within the first 30 days after surgery were recorded. Similar pCO2 gaps were found in patients with and without complications, except for the pCO2 gap at the end of surgery, which was higher in patients with complications (6.0 mmHg [5.0–8.0] vs. 6.0 mmHg [4.1–7.5], p = 0.005). The area under receiver operating characteristics curves for predicting complications from pCO2 gaps at all time points were between 0.5 and 0.6. A weak correlation between ScvO2 and pCO2 gaps was found for all timepoints (ρ was between − 0.40 and − 0.29 for all timepoints, p < 0.001). The pCO2 gap did not differ between GDT and standard care at any of the selected time points. In our study, pCO2 gap was a poor predictor of major postoperative complications at all selected time points. Our research does not support the use of pCO2 gap as a prognostic tool after high-risk abdominal surgery. pCO2 gaps were comparable between GDT and standard care. Clinical trial registration Netherlands Trial Registry NTR3380.

The effects of troponin screening among patients undergoing acute high-risk abdominal surgery: A retrospective cohort study.

Acute high-risk abdominal (AHA) surgery is associated with a high short-term mortality rate. This might be partly attributed to myocardial injury after non-cardiac surgery (MINS) defined by elevated postoperative troponin levels. The myocardial injury is often asymptomatic; thus, troponin screening seems to be the best diagnostic method. We aimed to assess whether implementing troponin screening with subsequent individualised interventions as standard care is associated with reduced mortality after AHA surgery. We also explored the treatment implications in the screening period. A retrospective cohort of 558 patients undergoing surgery from February 2018 to March 2021 was included. The patients undergoing surgery before March 2019 served as the historical control group, while the screening group consisted of patients undergoing surgery from March 1, 2019. Troponin I was to be measured 6-12 h postoperatively and in the morning of the succeeding 4 days. Patients with myocardial injury were assessed, and treatment was individualised after multiple disciplinary consultations. The primary outcome was the unadjusted 30-day mortality rates. Inverse probability treatment weighting was used to adjust for selection bias. We included 558 patients: 382 in the screening group and 176 in the historical control group. In the screening group, 15 patients (3.9%) died before the first blood sampling, and in 31 patients (8.1%), troponin screening was omitted, leaving only 336 patients screened. Myocardial injury was diagnosed in 81 patients (24.1%) of the 336 patients. Of these, 59 (72.8%) had a cardiac consultation. No interventions or alterations in relation to myocardial injury were done in 67 patients (82.7%). The 30-day mortality was 13.8% (95% CI 8.7%-18.9%) in the control group and 11.1% (95% CI 8.0%-14.3%) in the screening group. The absolute risk difference was -2.7% (95% CI -8.7%-3.3%; p = .38), which was unchanged after adjustment. The difference remained unchanged after 90 days and 1 year. The implementation of postoperative troponin screening was not associated with reduced mortality after AHA surgery. Research on the prevention and treatment of MINS is warranted before the implementation of standard troponin screening.

Diagnostic accuracy of the peripheral venous pressure variation induced by an alveolar recruitment maneuver to predict fluid responsiveness during high-risk abdominal surgery

BackgroundIn patients undergoing high-risk surgery, it is recommended to titrate fluid administration using stroke volume or a dynamic variable of fluid responsiveness (FR). However, this strategy usually requires the use of a hemodynamic monitor and/or an arterial catheter. Recently, it has been shown that variations of central venous pressure (ΔCVP) during an alveolar recruitment maneuver (ARM) can predict FR and that there is a correlation between CVP and peripheral venous pressure (PVP). This prospective study tested the hypothesis that variations of PVP (ΔPVP) induced by an ARM could predict FR.MethodsWe studied 60 consecutive patients scheduled for high-risk abdominal surgery, excluding those with preoperative cardiac arrhythmias or right ventricular dysfunction. All patients had a peripheral venous catheter, a central venous catheter and a radial arterial catheter linked to a pulse contour monitoring device. PVP was always measured via an 18-gauge catheter inserted at the antecubital fossa. Then an ARM consisting of a standardized gas insufflation to reach a plateau of 30 cmH2O for 30 s was performed before skin incision. Invasive mean arterial pressure (MAP), pulse pressure, heart rate, CVP, PVP, pulse pressure variation (PPV), and stroke volume index (SVI) were recorded before ARM (T1), at the end of ARM (T2), before volume expansion (T3), and one minute after volume expansion (T4). Receiver-operating curves (ROC) analysis with the corresponding grey zone approach were performed to assess the ability of ∆PVP (index test) to predict FR, defined as an ≥ 10% increase in SVI following the administration of a 4 ml/kg balanced crystalloid solution over 5 min.Results∆PVP during ARM predicted FR with an area under the ROC curve of 0.76 (95%CI, 0.63 to 0.86). The optimal threshold determined by the Youden Index was a ∆PVP value of 5 mmHg (95%CI, 4 to 6) with a sensitivity of 66% (95%CI, 47 to 81) and a specificity of 82% (95%CI, 63 to 94). The AUC’s for predicting FR were not different between ΔPVP, ΔCVP, and PPV.ConclusionDuring high-risk abdominal surgery, ∆PVP induced by an ARM can moderately predict FR. Nevertheless, other hemodynamic variables did not perform better.

P51 PERCUTANEOUS CLOSURE OF PATENT FORAMEN OVALE IN CHILDREN :SINGLE CENTER EXPERIENCE

Abstract Background Transcatheter patent foramen ovale (PFO) closure is a validated strategy to prevent recurrent cerebral events in adult patients; limited data are available for children. Methods This is a retrospective analysis including pediatric population underwent to percutaneous treatment of PFO in our center. Results From 2006 to 2021, 21 transcatheter PFO closures have been performed in children (mean age: 14 +3 years; female: 58%, weight: 59 + 20 kg). Indications for the closure of PFO consisted in the occurrence of cryptogenic ischemic events for 18 patients (86%), in disabling migraine symptoms for 2 patients (9,5%) and in prophylactic measure to prevent paradoxical embolism in high risk abdominal surgery for 1 patient (4,5%). Transcatheter PFO closure was performed under general anesthesia with transesophageal ultrasound guidance. Complex anatomies of PFO included atrial septal aneurysm in 4 cases (with accessory fenestration of atrial membrane in 2 of these cases) and long and stiff PFO tunnel in one case. Single device was used in 20 procedures. ASD closure device was required for 5 cases because of anatomic characteristics of PFO. In one case of large multifenestrated atrial septal aneurysm, percutaneous treatment was performed using both PFO closure device and ASD closure device. No peri and/or post procedural complications have been reported . All patients were treated with Acetylsalicylic acid and Clopidogrel for the first six months after the procedure. Conclusions Transcatheter PFO closure is a safe procedure in pediatric patients in high volume center that should be used for preventing recurrent cerebral events also in children.

Early intensive mobilization after acute high-risk abdominal surgery: a nonrandomized prospective feasibility trial.

Mobilization after emergency abdominal surgery is considered essential to facilitate rehabilitation and reduce postoperative complications. The aim of this study was to evaluate the feasibility of early intensive mobilization after acute high-risk abdominal (AHA) surgery. We conducted a nonrandomized, prospective feasibility trial of consecutive patients after AHA surgery at a university hospital in Denmark. The participants followed a predefined, interdisciplinary protocol for early intensive mobilization during the first 7 postoperative days (PODs) of their hospital admission. We evaluated feasibility in accordance with the percentage of patients who mobilized within 24 hours after surgery, mobilized at least 4 times per day and achieved daily goals of time out of bed and walking distance. We included 48 patients with a mean age of 61 (standard deviation 17) years (48% female). Within 24 hours after surgery, 92% of the patients were mobilized and 82% or more were mobilized at least 4 times per day over the first 7 PODs. On PODs 1-3, 70%-89% of the participants achieved the daily goals of mobilization; participants still in hospital after POD 3 were less able to achieve the daily goals. Patient reported that the primary factors limiting their level of mobilization were fatigue, pain and dizziness. Participants not mobilized independently on POD 3 (28%) had significantly (p ≤ 0.04) fewer hours out of bed (4 v. 8 h), were less able to achieve the goals of time out of bed (45% v. 95%) and walking distance (62% v. 94%) and had longer hospital stays (14 v. 6 d) than participants mobilized independently on POD 3. The early intensive mobilization protocol seems feasible for most patients after AHA surgery. For nonindependent patients, however, alternative mobilization strategies and goals should be investigated.

Standardized perioperative management in acute abdominal surgery: Swedish SMASH controlled study.

Acute high-risk abdominal surgery is common, as are the attendant risks of organ failure, need for intensive care, mortality, or long hospital stay. This study assessed the implementation of standardized management. A prospective study of all adults undergoing emergency laparotomy over an interval of 42 months (2018-2021) was undertaken; outcomes were compared with those of a retrospective control group. A new standardized clinical protocol was activated for all patients including: prompt bedside physical assessment by the surgeon and anaesthetist, interprofessional communication regarding location of resuscitation, elimination of unnecessary factors that might delay surgery, improved operating theatre competence, regular epidural, enhanced recovery care, and frequent early warning scores. The primary endpoint was 30-day mortality. Secondary endpoints were duration of hospital stay, need for intensive care, and surgical complications. A total of 1344 patients were included, 663 in the control group and 681 in the intervention group. The use of antibiotics increased (81.4 versus 94.7 per cent), and the time from the decision to operate to the start of surgery was reduced (3.80 versus 3.22 h) with use of the new protocol. Fewer anastomoses were performed (22.5 versus 16.8 per cent). The 30-day mortality rate was 14.5 per cent in the historical control group and 10.7 per cent in the intervention group (P = 0.045). The mean duration of hospital (11.9 versus 10.2 days; P = 0.007) and ICU (5.40 versus 3.12 days; P = 0.007) stays was also reduced. The rate of serious surgical complications (grade IIIb-V) was lower (37.6 versus 27.3 per cent; P = <0.001). Standardized management protocols improved outcomes after emergency laparotomy.

Comparison of two frailty indices in predicting life-threatening morbidity and mortality among older patients undergoing elective high-risk abdominal surgery.

Frailty predicts an increased risk of postoperative morbidity and mortality. Comparison of the predictive performance between two deficit accumulation models of frailty, the modified frailty index (mFI) and the revised-Risk Analysis Index (RAI-rev), is poorly understood. This study compared the predictive abilities of the above two frailty indices in predicting life-threatening morbidity and mortality among older patients following elective high-risk abdominal surgery. This retrospective cohort study extracted perioperative data of older patients (age ≥65 years) undergoing elective high-risk abdominal surgery at a single institution between January 2018 and December 2020. Preoperative frailty was screened by mFI and RAI-rev scoring systems. The primary outcome was the composite of postoperative life-threatening morbidity and mortality during hospitalization. Multivariable logistic regression analyses were performed to investigate the association of the two frailty indices with the primary outcome. Receiver-operating characteristic (ROC) curve was employed to test the predictive performances of the two frailty instruments in predicting the composite primary outcome. The difference between the area under the curves (AUCs) was assessed by DeLong's test. 1,132 older patients (mean age, 73.4 ± 6.2 years; 63.9% male) were included. Of these, 107 (9.5%) developed postoperative life-threatening morbidity and mortality. In multivariable logistic regression analyses, rising continuous frailty scores (mFI: adjusted OR 1.319 per 0.09-point increase in score, 95% CI 1.151-1.511, p < 0.001; RAI-rev: adjusted OR 1.052 per 1-point increase in score, 95% CI 1.018-1.087, p = 0.002) as well as dichotomized frailty measures (mFI ≥0.27: adjusted OR 2.059, 95% CI 1.328-3.193, p = 0.001; RAI-rev ≥45: adjusted OR 1.862, 95% CI 1.188-2.919, p = 0.007) were associated with increased odds of the primary outcome separately. ROC curve analysis showed that the discrimination of mFI and RAI-rev scores for the life-threatening morbidity and mortality was poor and comparable (AUC: 0.598 [95% CI 0.569-0.627] vs. 0.613 [95% CI 0.583-0.641]; DeLong's test: Z = 0.375, p = 0.7075). High mFI and RAI-rev scores were associated with an increased risk of life-threatening morbidity and mortality in older patients undergoing elective high-risk abdominal surgery. However, both frailty indices displayed poor discrimination for postoperative life-threatening morbidity and mortality.

Supplemental oxygen did not significantly affect two-year mortality in patients at-risk for cardiovascular complications undergoing moderate- to high-risk abdominal surgery–A follow-up analysis of a prospective randomized clinical trial

BackgroundIn relatively healthy middle-aged patients, recent studies have shown that supplemental oxygen did not significantly increase one-year mortality after noncardiac surgery. If supplemental oxygen influences long-term mortality, specifically in elderly patients with cardiovascular risk-factors, remains unknown. Thus, we evaluated the effect of supplemental oxygen on two-year mortality in patients with cardiovascular risk factors undergoing moderate- to high-risk major abdominal surgery.MethodsThis is a follow-up study of a prospective, randomized, double-blinded, clinical trial. Two hundred fifty-eight patients, who were at least 45 years of age and at-risk for cardiovascular complications were randomly assigned to receive 80 vs. 30% oxygen during surgery and for the first two postoperative hours. Vital status was obtained from all patients 2 years after surgery using the national registry. Preoperative and postoperative maximum concentrations of NT-proBNP, Troponin T (TnT), Copeptin, von Willebrand Factor (vWF), static oxidation-reduction potential (sORP) and oxidation-reduction potential capacity (cORP) were tested for association with two-year mortality.ResultsThe median age of patients was 74 years (25th-75th percentile 70–78 years). 25.8% (95% CI: 17.3–32.4%) of patients in the 80% oxygen group and 22.3% (95% CI: 14.8–29.1%) in the 30% oxygen group died within 2 years after surgery. No significant difference in two-year mortality was found between patients, who received 80% oxygen concentration, versus patients, who received 30% oxygen concentration (estimated hazard ratio 1.145; 95% CI 0.693–1.893; p = 0.597). Preoperative Copeptin concentrations and postoperative maximum vWF activity were significantly associated with two-year mortality (p &amp;lt; 0.001).ConclusionOur results are consistent with previous studies, that showed that supplemental oxygen did not increase long-term mortality. Therefore, it is becoming more evident that supplemental oxygen may not have a significant effect on long-term outcome in patients undergoing major abdominal surgery.

Perioperative changes in fluid distribution and haemodynamics in acute high-risk abdominal surgery

BackgroundUnderstanding the pathophysiology of fluid distribution in acute high-risk abdominal (AHA) surgery is essential in optimizing fluid management. There is currently no data on the time course and haemodynamic implications of fluid distribution in the perioperative period and the differences between the surgical pathologies.MethodsSeventy-three patients undergoing surgery for intestinal obstruction, perforated viscus, and anastomotic leakage within a well-defined perioperative regime, including intraoperative goal-directed therapy, were included in this prospective, observational study. From 0 to 120 h, we measured body fluid volumes and hydration status by bioimpedance spectroscopy (BIA), fluid balance (input vs. output), preload dependency defined as a > 10% increase in stroke volume after preoperative fluid challenge, and post-operatively evaluated by passive leg raise.ResultsWe observed a progressive increase in fluid balance and extracellular volume throughout the study, irrespective of surgical diagnosis. BIA measured variables indicated post-operative overhydration in 36% of the patients, increasing to 50% on the 5th post-operative day, coinciding with a progressive increase of preload dependency, from 12% immediately post-operatively to 58% on the 5th post-operative day and irrespective of surgical diagnosis. Patients with overhydration were less haemodynamically stable than those with normo- or dehydration.ConclusionDespite increased fluid balance and extracellular volumes, preload dependency increased progressively during the post-operative period. Our observations indicate a post-operative physiological incoherence between changes in the extracellular volume compartment and inadequate physiological preload control in patients undergoing AHA surgery. Considering the increasing overhydration during the observational period, our findings show that an indiscriminate correction of preload dependency with intravenous fluid bolus could lead to overhydration.Trial registration clinicaltrials.gov. (NCT03997721), Registered 23 May 2019, first participant enrolled 01 June 2019.

Systolic Arterial Pressure Control Using an Automated Closed-Loop System for Vasopressor Infusion during Intermediate-to-High-Risk Surgery: A Feasibility Study.

Introduction: Vasopressor infusions are essential in treating and preventing intraoperative hypotension. Closed-loop vasopressor therapy outperforms clinicians when the target is set at a mean arterial pressure (MAP) baseline, but little is known on the performance metrics of closed-loop vasopressor infusions when systolic arterial pressure (SAP) is the controlled variable. Methods: Patients undergoing intermediate- to high-risk abdominal surgery were included in this prospective cohort feasibility study. All patients received norepinephrine infusion through a computer controlled closed-loop system that targeted SAP at 130 mmHg. The primary objective was to determine the percent of case time in hypotension or under target defined as SAP below 10% of the target (SAP < 117 mmHg). Secondary objectives were the percent of case time “above target” (SAP > 10% of the target or >143 mmHg) and “in target” (within 10% of the SAP target or SAP between 117 and 143 mmHg). Results: A total of 12 patients were included. The closed-loop system infused norepinephrine for a median of 94.6% (25–75th percentile: 90.0–98.0%) of case time. The percentage of case time in hypotension or under target was only 1.8% (0.9–3.6%). The percentages of case time “above target” and “in target” were 4.7% (3.2–7.5%) and 92.4% (90.1–96.3%), respectively. Conclusions: This closed-loop vasopressor system minimizes intraoperative hypotension and maintains SAP within 10% of the target range for >90% of the case time in patients undergoing 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

BackgroundA 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.MethodsThis 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).ResultsAmong 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%.ConclusionIn 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.

Predicting loss of independence after high-risk gastrointestinal abdominal surgery: Frailty vs. NSQIP risk calculator

BackgroundLoss of independence (LOI) is a significant concern for patients undergoing high-risk abdominal surgery. Although the risk for morbidity and mortality has been well studied, there is a dearth of data on risk for LOI. MethodsThis study utilized NSQIP data from 2015 to 2018 in a retrospective cohort study of patients undergoing high-risk gastrointestinal surgery (e.g. gastric, colorectal, liver, and pancreatic). ResultsThe study included 229,573 patients who were preoperatively functionally independent. Of those, 5.3% experienced LOI. The median age for LOI patients was 74 (CI: 67–81), and 56% were female. The most common race was white (n = 9585), followed by African-American (n = 1223) and other (n = 369). The most common GI procedure was colorectal (65%), followed by the pancreas (23%), liver (8.2%), and gastric (3%). On univariate analysis, age, sex, BMI, race, frailty, and pancreatectomy were associated with LOI. On multivariate analysis age (≥85, OR 18.3 CI:16.9–19.9 p < 0.001), female sex (OR 1.24CI: 1.19–1.29 p < 0.001), BMI <18.5 (OR 1.66 CI:1.48–1.86 p < 0.001), BMI >40 (OR 1.43 CI:1.31–1.56 p < 0.001), African American race (OR 1.20 CI:1.12–1.28 p < 0.001), smoking (OR 1.21 CI:1.14–1.28 p < 0.001), frailty (MFI-5 > 2, OR 4.47 CI:2.63–7.31 p < 0.001), and pancreatectomy (OR 1.86 CI:1.74–1.98 p < 0.001) continued to be associated with LOI. To better define a predictive model, the NSQIP risk calculator was compared to the modified frailty index-5. AUC was 0.80 (CI: 0.797–0.805) and 0.76 (0.760–0.769), respectively. ConclusionLOI occurs in over five percent of patients undergoing high-risk abdominal surgery. LOI occurs more commonly after pancreatectomy or for those who are frail, underweight, or morbidly obese. Both frailty and the NSQIP risk calculator models similarly predicted LOI.

P343 VALIDATION OF ESC 2014 GUIDELINES PROTOCOL FOR CORONARY ARTERY DISEASE DETECTION IN PATIENTS CANDIDATES TO LIVER TRANSPLANTATION

Abstract Introduction Orthotopic liver transplantation (OLT) is the only effective treatment in patients with end–stage liver disease. Coronary artery disease (CAD) is associated with increased peri–operative OLT mortality. Thus, identification of CAD is crucial in pre–OLT evaluation. There is not a specific pre–OLT accepted diagnostic algorithm for CAD detection. 2014 ESC guidelines for non–cardiac surgery management consider OLT as a high–risk abdominal surgery and only patients with CAD history, suspected symptoms and low exercise capacity are invited to undergo to specific functional exams such as stress–echo. Purpose of the present study was to compare the ESC protocol with our cardiologic pre–OLT protocol, in which tests of ischemia and coronary CT are largely administered on based on presence of risk factors. Methods. From 2014 to 2021 all OLT candidates have been evaluated by visit, electrocardiography, rest and, when possible, stress echocardiography. In subject aged &amp;gt; 50 years with diabetes and/or two or more of the following risk factors: smoking, CAD family history, peripheral vascular disease, CT was performed. CGF was scheduled when CAD history and typical symptoms of angina. We theoretically re–analyse our database in order to consider the potential destiny of each patient in case of application of ECS 2014 protocol. We were able to calculate the differences in the number of potentially loss CAD diagnosis. Results. 367 patients (58.2%, age 57±5.7 years, males 74%) underwent OLT. Stress Echo was performed in 239 (65.1%) and positivity was found in 24 pz (6,5%). Coronary CT was performed in 95 (25,8%). CGF was performed in 75 patients (20.1%), 38 (9,2%) directly for known CAD and/or symptoms. Critical coronary lesions were found in 12 patients (3,2 %): 7 revascularized by PTCA, 1 by CABG and 4 medically managed, 25 patients had non critical lesions (7.8%), 31 patients (9.6%) referred to CGF were subsequently removed by transplant list, whereas OLT was successfully performed in PTCA patients (n = 8). During follow–up (35±20 months) 28 patients died (14.2%), 5 with symptoms of congestive heart failure, but no ischemic events were observed. Conclusions CAD detectionis remains a clinical challenge in candidates to OLT. The large number of normal stress echoes and normal CGF, even in presence of cardiovascular risk factors, demonstrates that CAD prevalence in ESLD is no higher than in general population, but a gold method to detect CAD is still unclear.

Validation of Two Activity Monitors in Slow and Fast Walking Hospitalized Patients.

To evaluate interventions to promote physical activity, valid outcome measures are important. This study evaluated the validity and reliability of the ActivPAL3™ and the SENS motion® activity monitors with regard to the number of steps taken, walking, and sedentary behavior in hospitalized patients (n = 36) (older medical patients (+65 years) (n = 12), older patients (+65) with acute hip fracture (n = 12), and patients (+18) who underwent acute high-risk abdominal surgery (n = 12)). Both monitors showed good (≥60%) percentage agreement with direct observation for standing and no. of steps (all gait speeds) and high agreement (≥80%) for lying. For walking, ActivPAL3™ showed moderate percentage agreement, whereas SENS motion® reached high percentage agreement. The relative reliability was moderate for sedentary behavior for both monitors. The ActivPAL3™ showed poor (walking) to moderate (steps) reliability for walking and steps, whereas SENS motion® showed moderate reliability for both activities. For slow walkers, the relative reliability was moderate for SENS motion® and poor for ActivPAL3™. This trial is registered with the ClinicalTrials.gov identifier NCT04120740.

Electrolyte and Acid–Base Disturbances in Emergency High‐Risk Abdominal Surgery, a Retrospective Study

Patients undergoing emergency high-risk abdominal surgery potentially suffer from both systemic dehydration and hypovolaemia. Data on the prevalence and clinical impact of electrolyte disturbances in this patient group, specifically the differences in patients with intestinal obstruction (IO) versus perforated viscus (PV) are lacking. Adult patients undergoing emergency high-risk abdominal surgery in a standardized perioperative pathway were included in this retrospective single-center cohort study. Electrolytes and arterial blood gas analysis were measured during the early perioperative period. Prevalence and clinical impact of electrolyte disturbances were assessed. A total of 354 patients were included in the study. Preoperative alkalemia dominated preoperatively, significantly more prevalent in IO (45 vs. 32%, p < .001), while acidosis was most pronounced postoperatively in PV (49 vs. 28%, p < .0001). Preoperative hypochloraemia and hypokalemia were more frequent in the IO (34 vs. 20% and 37 vs. 25%, respectively). Hyponatremia was highly prevalent in both IO and PV. Pre- and postoperative hypochloremia were independently associated with 30-day postoperative morbidity and mortality in patients with IO (OR 2.87 (1.35, 6.23) p = 0.006, OR 6.86 (1.71, 32.2) p = 0.009, respectively). Hypochloremic patients presented with reduced long-term survival as compared with the normo- and hyperchloremic patients (p < 0.05). Neither plasma sodium nor potassium showed asignificant association with outcome. These observations suggest that acute high-risk abdominal patients have frequent preoperative alkalosis shifting to postoperative acidosis. Both pre- and postoperative hypochloremia were independently associated with both impaired short- and long-term outcome in patients with intestinal obstruction, with potential implications for the choice of resuscitations fluids.

PCO2 gap, its ratio to arteriovenous oxygen content, ScvO2 and lactate in high-risk abdominal surgery patients: An observational study

BackgroundThe difference between arterial and central venous carbon dioxide partial pressure (PCO2 gap), a marker of oxygen delivery (DO2) and oxygen consumption (VO2) adequacy, has been evaluated as a promising prognostic tool in intensive care unit (ICU) patients. We therefore sought to study the association between intraoperative PCO2 gap and postoperative complications (POC) in the perioperative setting of elective major abdominal surgery. MethodsWe conducted a single-centre prospective observational study. All adult patients who underwent major planned abdominal surgery were eligible. PCO2 gap was measured every 2 h during surgery, at ICU admission and repeated 12 h and 24 h later. Severe POC within 28 days after surgery were defined as complications graded 3 or more according to Clavien-Dindo classification. Following a univariate analysis, a multivariable analysis using a logistic regression model was performed. ResultsNinety patients were included and divided into two groups according to the occurrence of POC. No significant difference was found between groups regarding baseline characteristics at inclusion. Thirty-nine (43%) patients developed postoperative complications. The median [IQR] intraoperative PCO2 gap was significantly higher in patients who had complications (6.5 [5.5−7.3] mmHg) compared to those who did not (5.0 [3.9–5.8] mmHg; p < 0.001). The area under the receiver operating characteristic curve for occurrence of POC was 0.78 for the PCO2 gap. After multivariable analysis, PCO2 gap was found independently associated with POC (OR: 14.9, 95% CI [4.68–60.1], p < 0.001) with a threshold value of 6.2 mmHg. The duration of surgery (OR: 1.01, 95% CI [1.00; 1.01], p = 0.04) and the need for vasoactive support during surgery (OR: 5.76, 95% CI [1.72; 24.1], p = 0.006) were also independently associated with POC. ConclusionIntraoperative PCO2 gap is a relevant predictive factor of severe postoperative complications in high-risk elective surgery patients. Trial registrationClinicalTrials.gov, NCT03914976.