Clinical mortality risk factors of variceal upper gastrointestinal bleeding in a Malagasy surgical intensive care unit.

BACKGROUND: Variceal upper gastrointestinal bleeding is a dreadful complication of portal hypertension with a significant morbidity and mortality. Different prognostic scores can be used. However, in the local context of Madagascar, the completion of paraclinical investigations can be delayed by the limited financial means of patients. Hence, determining clinical mortality risk factors of variceal upper gastrointestinal bleeding could be interesting. The aim of the study was to evaluate the clinical mortality risk factors of variceal gastrointestinal bleeding (VUGIB). METHOD: An observational, cohort retrospective study was conducted over an 8-year period (2010-2017), at the surgical intensive care unit of the J.R. Andrianavalona University Hospital, Antananarivo, in patients admitted for VUGIB confirmed by upper gastrointestinal endoscopy and whose clinical examination was performed at admission. The primary endpoint was intensive care unit (ICU) mortality. Univariate analysis and multivariate logistic regression analysis were performed to identify risk factors for ICU mortality, with OR defining odds ratio. A p value <0.05 was considered significant. RESULTS: 1920 patients were admitted for gastrointestinal bleeding of any digestive causes; the source of bleeding was variceal in 269 patients (14%). The predominantly male population (sex ratio = 2.5), aged 47.1 ± 13.7 years was mostly American Society of Anesthesiologists (ASA) 1 classification (58.4%). In 56.5% of patients, the gastrointestinal bleeding had not occurred before. The mortality rate was 16.0%. Three major clinical factors of mortality were identified: previous endoscopic band variceal ligation (OR = 12.57 [2.18-72.58], p = 0.005), tachycardia >120 bpm (OR = 2.91 [1.04-8.14], p = 0.041), and ascites (OR = 3.80 [1.85-7.81], p < 0.001). CONCLUSION: Upper gastrointestinal bleeding may be life-threatening. The mortality scores are certainly useful; however, the identification of clinical factors is interesting in countries like Madagascar, pending the results of paraclinical investigations.

Peri-operative management of pheochromocytoma with intravenous urapidil to prevent hemodynamic instability: A 17-year experience.

BACKGROUND AND AIMS: Surgery for pheochromocytoma (PCC) can cause excessive catecholamine release with severe hypertension. Alpha blockade is the mainstay of preoperative management. The aim of this study was to evaluate the efficacy and tolerance of intra-venous (IV) urapidil, a competitive short acting α1 receptor antagonist, in the prevention of peri-operative hemodynamic instability of patients with PCC. MATERIAL AND METHODS: This retrospective observational study included 75 patients (79 PCC) for PCC removal surgery from 2001 to 2017 at the Bordeaux University Hospital. They received, 3 days before surgery, continuous intravenous infusion of urapidil with stepwise increase to the maximum tolerated dose. Urapidil was maintained during the procedure and stopped after clamping the adrenal vein. Plasma catecholamine concentrations were measured during surgery. Hypertensive peaks (SAP >160 mmHg) and tachycardia >100 beats/min were treated with boluses of nicardipine 2 mg and esmolol 0.5 mg/kg. RESULTS: We recorded 20/79 (25%) cases with systolic arterial pressure (SAP) >180 mmHg. Only 11/79 (14%) had hypotension with SAP <80 mmHg. Peaks of catecholamine secretions were observed preferentially during peritoneal insufflation and tumor dissection (P < 0.05). A correlation was found between tumor size (mm) and the highest norepinephrine levels [r = 0.288, P = 0.015], and between hypertensive peaks (mmHg) and the highest norepinephrine levels [r = 0.45, P = 0.017]. No mortality was reported. The median [range] postoperative hospital stay was 4 [2-9] days. CONCLUSION: IV urapidil limits hypertensive and hypotensive peaks during PCC surgery, and corresponds to surgical imperatives allowing a short hospital stay, due to its "on-off" effect.

Long-term disability after blunt chest trauma: Don't miss chronic neuropathic pain!

Introduction The main objective of this prospective study was to assess the incidence of chronic pain and long-term respiratory disability in a single-center cohort of severe blunt chest trauma patients. Methods Over a 10-month period, all consecutive blunt chest trauma patients admitted in Intensive Care Unit (ICU) were screened to participate in a 3-month and 12-month follow-up. The following variables were prospectively assessed: persistence of chronic chest pain requiring regular used of analgesics, neuropathic pain, respiratory disability, physical and mental health status. Univariate and multivariable analysis were conducted to assess variables associated with chronic chest pain, neuropathic chest pain and respiratory disability. Results During the study period, 65 patients were included in the study. Chronic chest pain and respiratory disability were reported in 62% and 57% of patients respectively at 3 months postinjury. Neuropathic pain was reported in 22% of patients, associated with higher impairment of quality of life. A thoracic trauma severity score ≥12 and a pain score ≥4 at SICU discharge were the only variables significantly associated with the occurrence of neuropathic pain at 3 months (OR = 7 [2-32], p = 0.01 and OR = 16 [4-70], p < 0.0001). Conclusion According to the current study, chronic pain and long-term respiratory disability are very common after severe blunt chest trauma patients. Special attention should be paid to neuropathic pain, frequently under-diagnosed and responsible for significant impairment of quality of life.

Higher than standard dosing regimen are needed to achieve optimal antibiotic exposure in critically ill patients with augmented renal clearance receiving piperacillin-tazobactam administered by continuous infusion.

PURPOSE: To determine whether augmented renal clearance (ARC) impacts negatively on piperacillin-tazobactam unbound concentrations in critically ill patients receiving 16 g/2 g/day administered continuously. MATERIAL AND METHODS: Fifty nine critically ill patients without renal impairment underwent 24-h creatinine clearance (CrCL) measurement and therapeutic drug monitoring during the first three days of antimicrobial therapy by piperacillin-tazobactam. The main outcome was the rate of piperacillin underexposure, defined by at least one of three samples under 16 mg/L. Monte Carlo simulation was performed to predict the distribution of piperacillin concentrations for various CrCL and minimal inhibitory concentration (MIC) values. RESULTS: The rate of piperacillin underexposure was 19%, significantly higher in ARC patients (0 vs. 31%, p = .003). A threshold of CrCL ≥ 170 mL/min had a sensitivity and specificity of 1 (95%CI: 0.79-1) and 0.69 (95%CI: 0.61-0.76) to predict piperacillin underexposure. In ARC patients, a 20 g/2.5 g/24 h PTZ dosing regimen was associated with the highest probability to reach the 16 mg/L empirical target, without risk of excessive dosing. CONCLUSIONS: When targeting a theoretical MIC at the upper limit of the susceptibility range, the desirable target (100%fT>16) may not be achieved in patients with CrCL ≥ 170 mL/min receiving PTZ 16 g/2 g/day administered continuously.

Association between augmented renal clearance and clinical failure of antibiotic treatment in brain-injured patients with ventilator-acquired pneumonia: A preliminary study.

OBJECTIVES: This preliminary study aimed to determine whether augmented renal clearance (ARC) impacts negatively on the clinical outcome in traumatic brain-injured patients (TBI) treated for a first episode of ventilator-acquired pneumonia (VAP). METHODS: During a 5-year period, all TBI patients who had developed VAP were retrospectively reviewed to assess variables associated with clinical failure in multivariate analysis. Clinical failure was defined as an impaired clinical response with a need for escalating antibiotics during treatment and/or within 15 days after the end-of-treatment. Recurrence was considered if at least one of the initial causative bacterial strains was growing at a significant concentration from a second sample. Augmented renal clearance (ARC) was defined by an enhanced creatinine clearance exceeding 130mL/min/1.73m2 calculated from a urinary sample during the first three days of antimicrobial therapy. MAIN RESULTS: During the study period, 223 TBI patients with VAP were included and 59 (26%) presented a clinical failure. Factors statistically associated with clinical failure were GSC≤7 (OR=2.2 [1.1-4.4], P=0.03), early VAP (OR=3.9 [1.9-7.8], P=0.0001), bacteraemia (OR=11 [2.2-54], P=0.003) and antimicrobial therapy≤7 days (OR=3.7 [1.8-7.4], P=0.0003). ARC was statistically associated with recurrent infections with an OR of 4.4 [1.2-16], P=0.03. CONCLUSION: ARC was associated with recurrent infection after a first episode of VAP in TBI patients. The optimal administration and dosing of the antimicrobial agents in this context remain to be determined.

Bundle of care for blunt chest trauma patients improves analgesia but increases rates of intensive care unit admission: A retrospective case-control study.

INTRODUCTION: This single-centre retrospective case-control study aimed to assess the effectiveness of a multidisciplinary clinical pathway for blunt chest trauma patients admitted in emergency department (ED). PATIENTS AND METHODS: All consecutive blunt chest trauma patients with more than 3 rib fractures and no indication of mechanical ventilation were compared to a retrospective cohort over two 24-month periods, before and after the introduction of the bundle of care. Improvement of analgesia was the main outcome investigated in this study. The secondary outcomes were the occurrence of secondary respiratory complications (pneumonia, indication for mechanical ventilation, secondary ICU admission for respiratory failure or death), the intensive care unit (ICU) and hospital length of stay (LOS). RESULTS: Sixty-nine pairs of patients were matched using a 1:1 nearest neighbour algorithm adjusted on age and indices of severity. Between the two periods, there was a significant reduction of the rate of uncontrolled analgesia (55 vs. 17%, P<0.001). A significant increase in the rate of primary ICU transfer during the post-protocol period (23 vs. 52%, P<0.001) was not associated with a reduction of secondary respiratory complications or a reduction of ICU or hospital LOS. Only the use of non-steroidal anti-inflammatory drugs appeared to be associated with a significant reduction of secondary respiratory complications (OR=0.3 [0.1-0.9], P=0.03). CONCLUSION: Implementation of a multidisciplinary clinical pathway significantly improves pain control after ED management, but increases the rate of primary ICU admission without significant reduction of secondary respiratory complications.

Association between augmented renal clearance, antibiotic exposure and clinical outcome in critically ill septic patients receiving high doses of ß-lactams administered by continuous infusion: a prospective observational study.

This study assessed whether augmented renal clearance (ARC) impacts negatively on antibiotic concentrations and clinical outcomes in patients treated by high-dose ß-lactams administered continuously. Over a 9-month period, all critically ill patients without renal impairment treated by one of the monitored ß-lactams for a documented infection were eligible. During the first 3 days of antibiotic therapy, every patient underwent 24-h CLCr measurements and therapeutic drug monitoring. The main outcome was the rate of ß-lactam underdosing, defined as a free drug concentration <4 × MIC of the known pathogen. Secondary outcomes were rates of subexposure for ß-lactams and therapeutic failure. The performance of CLCr in predicting underdosing was assessed by a ROC curve, and multivariable logistic regression was performed to determine risk factors for subexposure and therapeutic failure. A total of 79 patients were included and 235 samples were analysed. The rate of underdosing<4×MIC was 12%, with a significant association with CLCr (P <0.0001). A threshold of CLCr ≥ 170 mL/min had a sensitivity and specificity of 0.93 (95% CI 0.77-0.99) and 0.65 (95% CI 0.58-0.71) for predicting ß-lactam underdosing<4×MIC. Mean CLCr values ≥170 mL/min were significantly associated with subexposure<4xMIC [OR = 10.1 (2.4-41.6); P = 0.001]. Patients with subexposure<4×MIC presented higher rates of therapeutic failure [OR = 6.3 (1.2-33.2); P = 0.03]. Mean CLCr values ≥170 mL/min remain a risk factor for subexposure to ß-lactams despite high doses of ß-lactams administered continuously. ß-Lactam subexposure was associated with higher rates of therapeutic failure in septic critically ill patients.

Impact of Systemic Vascular Resistance on the Accuracy of the Pulsioflex Device.

BACKGROUND: The accuracy of currently available devices using pulse contour analysis without external calibration for cardiac index (CI) estimation is negatively impacted by hyperdynamic states, low systemic vascular resistance (SVR), and abrupt changes in SVR. The aim of this study was to evaluate the accuracy of a new device, the Pulsioflex (Pulsion Medical System), in patients undergoing liver transplantation. METHODS: Thirty consecutive patients scheduled for liver transplantation were included. CI was monitored using pulmonary arterial catheter (CI-PAC) and Pulsioflex (CI-Pulsio). Simultaneous CI measurements were made intraoperatively at 9 different stages of the procedure. RESULTS: Two hundred seventy pairs of measurements were analyzed. The median CI-Pulsio values (3.3; interquartile range, 2.8-3.8 L·min·m) were significantly different from the median CI-PAC (4.1; interquartile range, 3.1-5.0 L·min·m; P < .0001). Bland and Altman analysis showed a mean bias of 0.8 L·min·m and 95% limit of agreement from -2.5 to 4.1 L·min·m. Percentage error was 65% (95% confidence interval, 60%-71%). Considering the variations in CI between 2 stages, the comparison between changes in CI-PAC and changes in CI-Pulsio showed a mean bias of 0.1 L·min·m and 95% limit of agreement of -2.1 to 2.2 L·min·m. When excluding changes in CI <0.5 L·min·m (154 paired analyzed), the concordance rate was 62% (95% confidence interval, 54%-70%). The bias between CI-PAC and CI-Pulsio was negatively correlated with SVR (r = -0.67, P < .0001). The bias between changes in CI-PAC and changes in CI-Pulsio was also negatively correlated with changes in SVR (r = -0.52, P < .0001). CONCLUSIONS: In patients undergoing liver transplantation, Pulsioflex does not accurately estimate CI. Its accuracy is highly impacted by SVR, and it is not able to track changes in CI when large variations in SVR occur.

Automated, continuous and non-invasive assessment of pulse pressure variations using CNAP® system.

Non-invasive respiratory variations in arterial pulse pressure using infrared-plethysmography (PPVCNAP) are able to predict fluid responsiveness in mechanically ventilated patients. However, they cannot be continuously monitored. The present study evaluated a new algorithm allowing continuous measurements of PPVCNAP (PPVCNAPauto) (CNSystem, Graz, Austria). Thirty-five patients undergoing vascular surgery were studied after induction of general anaesthesia. Stroke volume was measured using the VigileoTM/FloTracTM. Invasive pulse pressure variations were manually calculated using an arterial line (PPVART) and PPVCNAPauto was continuously displayed. PPVART and PPVCNAPauto were simultaneously recorded before and after volume expansion (500 ml hydroxyethylstarch). Subjects were defined as responders if stroke volume increased by ≥15 %. Twenty-one patients were responders. Before volume expansion, PPVART and PPVCNAPauto exhibited a bias of 0.1 % and limits of agreement from -7.9 % to 7.9 %. After volume expansion, PPVART and PPVCNAPauto exhibited a bias of -0.4 % and limits of agreement from -5.3 % to 4.5 %. A 14 % baseline PPVART threshold discriminated responders with a sensitivity of 86 % (95 % CI 64-97 %) and a specificity of 100 % (95 % CI 77-100 %). Area under the receiver operating characteristic (ROC) curve for PPVART was 0.93 (95 % CI 0.79-0.99). A 15 % baseline PPVCNAPauto threshold discriminated responders with a sensitivity of 76% (95 % CI 53-92 %) and a specificity of 93 % (95 % CI 66-99 %). Area under the ROC curves for PPVCNAPauto was 0.91 (95 % CI 0.76-0.98), which was not different from that for PPVART. When compared with PPVART, PPVCNAPauto performs satisfactorily in assessing fluid responsiveness in hemodynamically stable surgical patients.

Postpartum haemorrhage: prevention and treatment.

INTRODUCTION: Postpartum hemorrhage (PPH) is one of the leading causes of maternal death and severe maternal morbidity worldwide and strategies to prevent and treat PPH vary among international authorities. Areas covered: This review seeks to provide a global overview of PPH (incidence, causes, risk factors), prevention (active management of the third stage of labor and prohemostatic agents), treatment (first, second and third-line measures to control PPH), by also underlining recommendations elaborated by international authorities and using algorithms. Expert commentary: When available, oxytocin is considered the drug of first choice for both prevention and treatment of PPH, while peripartum hysterectomy remains the ultimate life-saving procedure if pharmacological and resuscitation measures fail. Nevertheless, the level of evidence for preventing and treating PPH is globally low. The emergency nature of PPH makes randomized controlled trials (RCT) logistically difficult. Population-based observational studies should be encouraged as they can usefully strengthen the evidence base, particularly for components of PPH treatment that are difficult or impossible to assess through RCT.

Rivaroxaban and apixaban in orthopaedics: is there a difference in their plasma concentrations and anticoagulant effects?

The aim of this study was to improve knowledge of what happens in the coagulation of orthopaedic patients under rivaroxaban and apixaban, in order to finalize and cross-validate effective measurement methods and to provide arguments for helping to reference one or the other drug in our central pharmacy. One hundred and two patients undergoing total hip or knee replacement were included. Half of them received rivaroxaban and the other half received apixaban. Blood samples (n = 244 with each drug) were taken at Cmax preoperatively and twice a week, apart from the day of the patient's discharge, when Ctrough concentration was targeted. Routine coagulation parameters, and functional and liquid chromatography tandem mass spectrometry assays for measurement of circulating concentrations were studied. The LC-MS/MS assay and the functional assays carried out in patients under routine conditions were highly correlated, apart from low concentrations (<30 ng/ml), which were affected by the variable individual potential to inhibit the exogenous bovine Xa used in the functional assays. After 1 week of treatment, the drugs differed: Cmax and Ctrough were closer when apixaban was taken twice daily (83 ±â€Š39 and 58 ±â€Š17 ng/ml) than with rivaroxaban taken once a day (113 ±â€Š67 and 13 ±â€Š20 ng/ml). Rivaroxaban had a greater influence on routine coagulation tests and reduced the maximum thrombin concentration more efficiently, as assessed by the thrombin generation test. Although rivaroxaban and apixaban present apparently similar constant rates, they exhibit significant differences in their concentrations and anticoagulant effects when studied ex vivo in orthopedic patients.

The Script Concordance Test in anesthesiology: Validation of a new tool for assessing clinical reasoning.

OBJECTIVE: To evaluate whether the Script Concordance Test (SCT) can discriminate between levels of experience among anesthesiology residents and attending physicians. STUDY TYPE: Multicenter (Toulouse, Nantes, Bordeaux and Limoges), prospective, observational study. PATIENTS AND METHODS: A SCT made of 60 items was used to evaluate "junior residents" (n=60), "senior residents" (n=47) and expert anesthesiologists (n=10). RESULTS: There were no missing data in our study. Mean scores (±SD) were 69.9 (±6.1), 73.1 (±6.5) and 82.0 (±3.5) out of a potential score of 100 for "junior residents", "senior residents" and expert anesthesiologists, respectively. Results were statistically different between the 3 groups (P=0.001) using the Kruskall-Wallis test. The Cronbach's α score was 0.63. CONCLUSIONS: The SCT is a valid and useful tool for discriminating between anesthesia providers with varying levels of experience in anesthesiology. It may be a useful tool for documenting the progression of reasoning during anesthesia residency.

Management of bleeding and transfusion during liver transplantation before and after the introduction of a rotational thromboelastometry-based algorithm.

Orthotopic liver transplantation (OLT) remains a potentially hemorrhagic procedure. Rotational thromboelastometry (ROTEM) is a point-of-care device used to monitor coagulation during OLT. Whether it allows blood loss and transfusions to be reduced during OLT remains controversial. Excellent correlations and predictive values have been found between ROTEM parameters and fibrinogen. We hypothesized that the use of a ROTEM-based transfusion algorithm during OLT would lead to more fibrinogen transfusion and decreased bleeding and blood transfusion. Sixty adult patients were consecutively included in a prospective, without-versus-with study: 30 in the group without ROTEM results and 30 in the group with the ROTEM-based algorithm. A small and nonsignificant increase in median fibrinogen transfusions was found for the with group (6.0 g versus 4.5 g, P = 0.50). It was not associated with a decrease in blood transfusions or in the number of patients exposed to blood products.

Benefits of intravenous lidocaine on post-operative pain and acute rehabilitation after laparoscopic nephrectomy.

BACKGROUND AND AIMS: Intravenous (I.V.) lidocaine has analgesic, antihyperalgesic and anti-inflammatory properties and is known to accelerate the return of bowel function after surgery. We evaluated the effects of I.V. lidocaine on pain management and acute rehabilitation protocol after laparoscopic nephrectomy. MATERIALS AND METHODS: A total of 47 patients scheduled to undergo laparoscopic nephrectomy were included in a two-phase observational study where I.V. lidocaine (1.5 mg/kg/h) was introduced, in the second phase, during surgery and for 24 h post-operatively. All patients underwent the same post-operative rehabilitation program. Post-operative pain scores, opioid consumption and extent of hyperalgesia were measured. Time to first flatus and 6 min walking test (6MWT) were recorded. RESULTS: Patient demographics were similar in the two phases (n = 22 in each group). Lidocaine significantly reduced morphine consumption (median [25-75% interquartile range]; 8.5 mg[4567891011121314151617] vs. 25 mg[1920212223242526272829303132]; P < 0.0001), post-operative pain scores (P < 0.05) and hyperalgesia extent on post-operative day 1-day 2-day 4 (mean ± standard deviation (SD); 1.5 ± 0.9 vs. 4.3 ± 1.2 cm (P < 0.001), 0.6 ± 0.5 vs. 2.8 ± 1.2 cm (P < 0.001) and 0.13 ± 0.3 vs. 1.2 ± 1 cm (P < 0.001), respectively). Time to first flatus (mean ± SD; 29 ± 7 h vs. 48 ± 15 h; P < 0.001) and 6MWT at day 4 (189 ± 50 m vs. 151 ± 53 m; P < 0.001) were significantly enhanced in patients with i.v. lidocaine. CONCLUSION: Intravenous (I.V.) lidocaine could reduce post-operative morphine consumption and improve post-operative pain management and post-operative recovery after laparoscopic nephrectomy. I.V. lidocaine could contribute to better post-operative rehabilitation.

High-protein enteral nutrition enriched with immune-modulating nutrients vs standard high-protein enteral nutrition and nosocomial infections in the ICU: a randomized clinical trial.

IMPORTANCE: Enteral administration of immune-modulating nutrients (eg, glutamine, omega-3 fatty acids, selenium, and antioxidants) has been suggested to reduce infections and improve recovery from critical illness. However, controversy exists on the use of immune-modulating enteral nutrition, reflected by lack of consensus in guidelines. OBJECTIVE: To determine whether high-protein enteral nutrition enriched with immune-modulating nutrients (IMHP) reduces the incidence of infections compared with standard high-protein enteral nutrition (HP) in mechanically ventilated critically ill patients. DESIGN, SETTING, AND PARTICIPANTS: The MetaPlus study, a randomized, double-blind, multicenter trial, was conducted from February 2010 through April 2012 including a 6-month follow-up period in 14 intensive care units (ICUs) in the Netherlands, Germany, France, and Belgium. A total of 301 adult patients who were expected to be ventilated for more than 72 hours and to require enteral nutrition for more than 72 hours were randomized to the IMHP (n = 152) or HP (n = 149) group and included in an intention-to-treat analysis, performed for the total population as well as predefined medical, surgical, and trauma subpopulations. INTERVENTIONS: High-protein enteral nutrition enriched with immune-modulating nutrients vs standard high-protein enteral nutrition, initiated within 48 hours of ICU admission and continued during the ICU stay for a maximum of 28 days. MAIN OUTCOMES AND MEASURES: The primary outcome measure was incidence of new infections according to the Centers for Disease Control and Prevention (CDC) definitions. Secondary end points included mortality, Sequential Organ Failure Assessment (SOFA) scores, mechanical ventilation duration, ICU and hospital lengths of stay, and subtypes of infections according CDC definitions. RESULTS: There were no statistically significant differences in incidence of new infections between the groups: 53% (95% CI, 44%-61%) in the IMHP group vs 52% (95% CI, 44%-61%) in the HP group (P = .96). No statistically significant differences were observed in other end points, except for a higher 6-month mortality rate in the medical subgroup: 54% (95% CI, 40%-67%) in the IMHP group vs 35% (95% CI, 22%-49%) in the HP group (P = .04), with a hazard ratio of 1.57 (95% CI, 1.03-2.39; P = .04) for 6-month mortality adjusted for age and Acute Physiology and Chronic Health Evaluation II score comparing the groups. CONCLUSIONS AND RELEVANCE: Among adult patients breathing with the aid of mechanical ventilation in the ICU, IMHP compared with HP did not improve infectious complications or other clinical end points and may be harmful as suggested by increased adjusted mortality at 6 months. These findings do not support the use of IMHP nutrients in these patients. TRIAL REGISTRATION: trialregister.nl Identifier: NTR2181.

Predicting fluid responsiveness during infrarenal aortic cross-clamping in pigs.

OBJECTIVE: Infrarenal aortic cross-clamping (ACC) induces hemodynamic disturbances that may affect respiratory-induced variations in stroke volume and, therefore, affect the ability of dynamic parameters such as pulse-pressure variation (PPV) to predict fluid responsiveness. Since this issue has not been investigated yet to authors' knowledge, the hypothesis was tested that ACC may change PPV and impair its ability to predict fluid responsiveness. DESIGN: Prospective laboratory experiment. SETTING: A university research laboratory. PARTICIPANTS: Nineteen anesthetized and mechanically ventilated pigs. INTERVENTIONS: Two courses of volume expansion were performed using 500 mL of saline before and during ACC. Animals were monitored using a systemic arterial catheter, and a pulmonary arterial catheter (stroke volume, central venous pressure, pulmonary arterial occlusion pressure). Animals were defined as responders to volume expansion if stroke volume increased ≥ 15%. RESULTS: Before ACC, 13 animals were responders. Fluid responsiveness was predicted by a PPV ≥ 14% with a sensitivity of 77% (95% CI = 46%-95%) and a specificity of 83% (95% CI = 36%-97%). The area under the receiver operating characteristic curve was 0.90(95% CI = 0.67-0.99) and was higher than those generated for central venous pressure and pulmonary arterial occlusion pressure. ACC induced an increase in PPV (p<0.0005). During ACC, 8 animals were responders. An 18% PPV threshold discriminated between responders and non-responders to volume expansion, with a sensitivity of 87% (95% CI = 47%-98%) and a specificity of 54% (95% CI = 23%-83%). The area under the receiver operating characteristic curve was 0.72 (95% CI = 0.47-0.90) and was not different from those generated for central venous pressure and pulmonary arterial occlusion pressure. CONCLUSIONS: ACC induced a significant increase in PPV and reduced its ability to predict fluid responsiveness.