Maintenance of beta-blockers and cardiac surgery-related outcomes: a prospective propensity-matched multicentre analysis.

BACKGROUND: We investigated the effects of maintaining beta-blockers on the day of surgery on the incidence of atrial fibrillation and postoperative acute kidney injury (AKI) in patients undergoing cardiac surgery. METHODS: We conducted a multicentre prospective observational study with propensity matching on patients treated with beta-blockers. We collected their baseline patient characteristics, comorbidities, and operative and postoperative outcomes. The endpoints were postoperative atrial fibrillation and AKI after cardiac surgery. RESULTS: Of the 1789 included patients, propensity matching led to 583 patients in each group. Maintenance of beta-blockers was not associated with a reduced risk of atrial fibrillation (odds ratio: 0.86 [95% confidence interval 0.66-1.14], P=0.335; 141 patients [24.2%] vs 126 patients [21.6%]). Sensitivity analysis did not demonstrate association between beta-blocker maintenance and atrial fibrillation after cardiac surgery (odds ratio: 0.93 [95% confidence interval: 0.72-1.22], P=0.625). Maintenance of beta-blockers was associated with a higher rate of norepinephrine use (415 [71.2%] vs 465 [79.8%], P=0.0001) and postoperative AKI (124 [21.3%] vs 159 [27.3%], P=0.0127). No statistically significant difference was observed in ICU length of stay. CONCLUSIONS: Maintenance of beta-blockers on the day of surgery was not associated with a reduced incidence of postoperative atrial fibrillation. However, maintenance of beta-blockers was associated with increased usage of vasopressors, potentially contributing to adverse postoperative renal events. CLINICAL TRIAL REGISTRATION: NCT04769752.

Occurrences of post-traumatic stress disorder, anxiety, depression, and burnout syndrome in ICU staff workers after two-year of the COVID-19 pandemic: the international PSY-CO in ICU study.

PURPOSE: The present study aimed at assessing the prevalences of post-traumatic stress disorder (PTSD) (main objective), anxiety, depression, and burnout syndrome (BOS) and their associated factors in intensive care unit (ICU) staff workers in the second year of the COVID-19 pandemic. MATERIALS AND METHODS: An international cross-sectional multicenter ICU-based online survey was carried out among the ICU staff workers in 20 ICUs across 3 continents. ICUs staff workers (both caregivers and non-caregivers) were invited to complete PCL-5, HADS, and MBI questionnaires for assessing PTSD, anxiety, depression, and the different components of BOS, respectively. A personal questionnaire was used to isolate independent associated factors with these disorders. RESULTS: PCL-5, HADS, and MBI questionnaires were completed by 585, 570, and 539 responders, respectively (525 completed all questionnaires). PTSD was diagnosed in 98/585 responders (16.8%). Changing familial environment, being a non-caregiver staff worker, having not being involved in a COVID-19 patient admission, having not been provided with COVID-19-related information were associated with PTSD. Anxiety was reported in 130/570 responders (22.8%). Working in a public hospital, being a woman, being financially impacted, being a non-clinical healthcare staff member, having no theoretical or practical training on individual preventive measures, and fear of managing COVID-19 patients were associated with anxiety. Depression was reported in 50/570 responders (8.8%). Comorbidity at risk of severe COVID-19, working in a public hospital, looking after a child, being a non-caregiver staff member, having no information, and a request for moving from the unit were associated with depression. Having received no information and no adequate training for COVID-19 patient management were associated with all 3 dimensions of BOS. CONCLUSION: The present study confirmed that ICU staff workers, whether they treated COVID-19 patients or not, have a substantial prevalence of psychological disorders.

Perioperative individualized hemodynamic optimization according to baseline mean arterial pressure in cardiac surgery patients: Rationale and design of the OPTIPAM randomized trial.

BACKGROUND: Postoperative morbidity and mortality after cardiac surgery with cardiopulmonary bypass (CPB) remain high despite recent advances in both anesthesia and perioperative management. Among modifiable risk factors for postoperative complications, optimal arterial pressure during and after surgery has been under debate for years. Recent data suggest that optimizing arterial pressure to the baseline of the patient may improve outcomes. We hypothesize that optimizing the mean arterial pressure (MAP) to the baseline MAP of the patient during cardiac surgery with CPB and during the first 24 hours postoperatively may improve outcomes. STUDY DESIGN: The OPTIPAM trial (NCT05403697) will be a multicenter, randomized, open-label controlled trial testing the superiority of optimized MAP management as compared with a MAP of 65 mm Hg or more during both the intraoperative and postoperative periods in 1,100 patients scheduled for cardiac surgery with CPB. The primary composite end point is the occurrence of acute kidney injury, neurological complications including stroke or postoperative delirium, and death. The secondary end points are hospital and intensive care unit lengths of stay, Day 7 and Day 90 mortality, postoperative cognitive dysfunction on Day 7 and Day 90, and quality of life at Day 7 and Day 90. Two interim analyses will assess the safety of the intervention. CONCLUSION: The OPTIPAM trial will assess the effectiveness of an individualized target of mean arterial pressure in cardiac surgery with CPB in reducing postoperative morbidity. CLINICAL TRIAL REGISTRATION: NCT05403697.

A Multimodal Cardioprotection Strategy During Cardiac Surgery: The ProCCard Study.

OBJECTIVE: The ProCCard study tested whether combining several cardioprotective interventions would reduce the myocardial and other biological and clinical damage in patients undergoing cardiac surgery. DESIGN: Prospective, randomized, controlled trial. SETTING: Multicenter tertiary care hospitals. PARTICIPANTS: 210 patients scheduled to undergo aortic valve surgery. INTERVENTIONS: A control group (standard of care) was compared to a treated group combining five perioperative cardioprotective techniques: anesthesia with sevoflurane, remote ischemic preconditioning, close intraoperative blood glucose control, moderate respiratory acidosis (pH 7.30) just before aortic unclamping (concept of the "pH paradox"), and gentle reperfusion just after aortic unclamping. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the postoperative 72-h area under the curve (AUC) for high-sensitivity cardiac troponin I (hsTnI). Secondary endpoints were biological markers and clinical events occurring during the 30 postoperative days and the prespecified subgroup analyses. The linear relationship between the 72-h AUC for hsTnI and aortic clamping time, significant in both groups (p < 0.0001), was not modified by the treatment (p = 0.57). The rate of adverse events at 30 days was identical. A non-significant reduction of the 72-h AUC for hsTnI (-24%, p = 0.15) was observed when sevoflurane was administered during cardiopulmonary bypass (46% of patients in the treated group). The incidence of postoperative renal failure was not reduced (p = 0.104). CONCLUSION: This multimodal cardioprotection has not demonstrated any biological or clinical benefit during cardiac surgery. The cardio- and reno-protective effects of sevoflurane and remote ischemic preconditioning therefore remain to be demonstrated in this context.

Individualised or liberal red blood cell transfusion after cardiac surgery: a randomised controlled trial.

BACKGROUND: Current practice guidelines for red blood cell (RBC) transfusion in ICUs are based on haemoglobin threshold, without consideration of oxygen delivery or consumption. We aimed to evaluate an individual physiological threshold-guided by central venous oxygen saturation ScvO2. METHODS: In a randomised study in two French academic hospitals, 164 patients who were admitted to ICU after cardiac surgery with postoperative haemoglobin <9 g dl-1 were randomised to receive a transfusion with one unit of RBCs (haemoglobin group) or transfusion only if the ScvO2 was <70% (individualised group). The primary outcome was the number of subjects receiving at least one unit of RBCs. The secondary composite outcome was acute kidney injury, stroke, myocardial infarction, acute heart failure, mesenteric ischaemia, or in-hospital mortality. One- and 6-month mortality were evaluated during follow-up. RESULTS: The primary outcome was observed for 80 of 80 subjects (100%) in the haemoglobin group and in 61 of 77 patients (79%) in the individualised group (absolute risk -21% [-32.0; -14.0]; P<0.001). There was no significant difference in the secondary outcome between the two groups. Follow-up showed a non-significant difference in mortality at 1 and 6 months. CONCLUSIONS: An individualised strategy based on an central venous oxygen saturation threshold of 70% allows for a more restrictive red blood cell transfusion strategy with no incidence on postoperative morbidity or 6-month mortality. CLINICAL TRIAL REGISTRATION: NCT02963883.

Passive leg raising-induced changes in pulse pressure variation to assess fluid responsiveness in mechanically ventilated patients: a multicentre prospective observational study.

BACKGROUND: Passive leg raising-induced changes in cardiac index can be used to predict fluid responsiveness. We investigated whether passive leg raising-induced changes in pulse pressure variation (ΔPPVPLR) can also predict fluid responsiveness in mechanically ventilated patients. METHODS: In this multicentre prospective observational study, we included 270 critically ill patients on mechanical ventilation in whom volume expansion was indicated because of acute circulatory failure. We did not include patients with cardiac arrythmias. Cardiac index and PPV were measured before/during a passive leg raising test and before/after volume expansion. A volume expansion-induced increase in cardiac index of >15% defined fluid responsiveness. To investigate whether ΔPPVPLR can predict fluid responsiveness, we determined areas under the receiver operating characteristic curves (AUROCs) and grey zones for relative and absolute ΔPPVPLR. RESULTS: Of the 270 patients, 238 (88%) were on controlled mechanical ventilation with no spontaneous breathing activity and 32 (12%) were on pressure support ventilation. The median tidal volume was 7.1 (inter-quartile range [IQR], 6.6-7.6) ml kg-1 ideal body weight. One hundred sixty-four patients (61%) were fluid responders. Relative and absolute ΔPPVPLR predicted fluid responsiveness with an AUROC of 0.92 (95% confidence interval [95% CI], 0.88-0.95; P<0.001) each. The grey zone for relative and absolute ΔPPVPLR included 4.8% and 22.6% of patients, respectively. These results were not affected by ventilatory mode and baseline characteristics (type of shock, centre, vasoactive treatment). CONCLUSIONS: Passive leg raising-induced changes in pulse pressure variation accurately predict fluid responsiveness with a small grey zone in critically ill patients on mechanical ventilation. CLINICAL TRIAL REGISTRATION: NCT03225378.

Postoperative Pulmonary Complications After Cardiac Surgery: The VENICE International Cohort Study.

OBJECTIVE: Postoperative pulmonary complications (PPC) remain a main issue after cardiac surgery. The objective was to report the incidence and identify risk factors of PPC after cardiac surgery. DESIGN: An international multicenter prospective study (42 international centers in 9 countries). PARTICIPANTS: A total of 707 adult patients who underwent cardiac surgery under cardiopulmonary bypass. INTERVENTIONS: None MEASUREMENTS AND MAIN RESULTS: During a study period of 2 weeks, the investigators included all patients in their respective centers and screened for PPCs. PPC was defined as the occurrence of at least 1 pulmonary complication among the following: atelectasis, pleural effusion, respiratory failure, respiratory infection, pneumothorax, bronchospasm, or aspiration pneumonitis. Among 676 analyzed patients, 373 patients presented with a PPC (55%). The presence of PPC was significantly associated with a longer intensive care length of stay and hospital length of stay. One hundred ninety (64%) patients were not intraoperatively ventilated during cardiopulmonary bypass. Ventilation settings were similar regarding tidal volume, respiratory rate, inspired oxygen. In the regression model, age, the Euroscore II, chronic obstructive pulmonary disease, preoxygenation modality, intraoperative positive end-expiratory pressure, the absence of pre- cardiopulmonary bypass ventilation, the absence of lung recruitment, and the neuromuscular blockade were associated with PPC occurrence. CONCLUSION: Both individual risk factors and ventilatory settings were shown to explain the high level of PPCs. These findings require further investigations to assess a bundle strategy for optimal ventilation strategy to decrease PPC incidence.

Anti-Xa activity and hemorrhagic events under extracorporeal membrane oxygenation (ECMO): a multicenter cohort study.

BACKGROUND: Hemorrhagic events remain a major concern in patients under extracorporeal membrane oxygenation (ECMO) support. We tested the association between anticoagulation levels and hemorrhagic events under ECMO using anti-Xa activity monitoring. METHODS: We performed a retrospective multicenter cohort study in three ECMO centers. All adult patients treated with veno-venous (VV)- or veno-arterial (VA)-ECMO in 6 intensive care units between September 2017 and August 2019 were included. Anti-Xa activities were collected until a hemorrhagic event in the bleeding group and for the duration of ECMO in the non-bleeding group. All dosages were averaged to obtain means of anti-Xa activity for each patient, and patients were compared according to the occurrence or not of bleeding. RESULTS: Among 367 patients assessed for eligibility, 121 were included. Thirty-five (29%) presented a hemorrhagic complication. In univariate analysis, anti-Xa activities were significantly higher in the bleeding group than in the non-bleeding group, both for the mean anti-Xa activity (0.38 [0.29-0.67] vs 0.33 [0.22-0.42] IU/mL; p = 0.01) and the maximal anti-Xa activity (0.83 [0.47-1.46] vs 0.66 [0.36-0.91] IU/mL; p = 0.05). In the Cox proportional hazard model, mean anti-Xa activity was associated with bleeding (p = 0.0001). By Kaplan-Meier analysis with the cutoff value at 0.46 IU/mL obtained by ROC curve analysis, the probability of survival under ECMO without bleeding was significantly lower when mean anti-Xa was > 0.46 IU/mL (p = 0.0006). CONCLUSION: In critically ill patients under ECMO, mean anti-Xa activity was an independent risk factor for hemorrhagic complications. Anticoagulation targets could be revised downward in both VV- and VA-ECMO.

Central Venous-to-Arterial PCO2 Difference and Central Venous Oxygen Saturation in the Detection of Extubation Failure in Critically Ill Patients.

OBJECTIVES: To evaluate the ability of central venous-to-arterial carbon dioxide pressure difference, central venous oxygen saturation, and the combination of these two parameters to detect extubation failure in critically ill patients. DESIGN: Multicentric, prospective, observational study. SETTING: Three ICUs. PATIENTS: All patients who received mechanical ventilation for more than 48 hours and tolerated spontaneous breathing trials with a T-piece for 60 minutes. INTERVENTIONS: Extubation after successful spontaneous breathing trials. Extubation failure was defined as the need for mechanical ventilation within 48 hours. MEASUREMENTS AND MAIN RESULTS: The oxygen delivery index, oxygen consumption index, central venous oxygen saturation, central venous-to-arterial carbon dioxide pressure difference, and oxygen extraction were measured immediately before spontaneous breathing trials and at 60 minutes after spontaneous breathing trials initiation. Seventy-five patients were enrolled, and extubation failure was noted in 18 (24%) patients. Oxygen consumption index increased significantly during spontaneous breathing trials in the failure group. Oxygen delivery index increased in both success and failure groups. Oxygen extraction increased in the failure group (p = 0.005) and decreased in the success group (p = 0.001). Central venous oxygen saturation decreased in the failure group and increased in the success group (p = 0.014). ΔPCO2 value increased in the extubation failure group and decreased in the success group (p = 0.002). Changes in ΔPCO2 (Δ - ΔPCO2) and central venous oxygen saturation (ΔScvO2) during spontaneous breathing trials were independently associated with extubation failure (odds ratio, 1.02; 95% CI, 1.01-1.05; p = 0.006, and odds ratio, 0.84; 95% CI, 0.70-0.95; p = 0.02, respectively). Δ - ΔPCO2 and central venous oxygen saturation could predict extubation failure with areas under the curve of 0.865 and 0.856, respectively; however, their combined areas under the curve was better at 0.940. CONCLUSIONS: We found that Δ - ΔPCO2 and central venous oxygen saturation, during spontaneous breathing trials, were independent predictors of weaning outcomes. Combination analysis of both parameters enhanced their diagnostic performance and provided excellent predictability in extubation failure detection in critically ill patients.

Individualized Fluid Management Using the Pleth Variability Index: A Randomized Clinical Trial.

BACKGROUND: The present trial was designed to assess whether individualized strategies of fluid administration using a noninvasive plethysmographic variability index could reduce the postoperative hospital length of stay and morbidity after intermediate-risk surgery. METHODS: This was a multicenter, randomized, nonblinded parallel-group clinical trial conducted in five hospitals. Adult patients in sinus rhythm having elective orthopedic surgery (knee or hip arthroplasty) under general anesthesia were enrolled. Individualized hemodynamic management aimed to achieve a plethysmographic variability index under 13%, and the standard management strategy aimed to maintain a mean arterial pressure above 65 mmHg during general anesthesia. The primary outcome was the postoperative hospital length of stay decided by surgeons blinded to the group allocation of the patient. RESULTS: In total, 447 patients were randomized, and 438 were included in the analysis. The mean hospital length of stay ± SD was 6 ± 3 days for the plethysmographic variability index group and 6 ± 3 days for the control group (adjusted difference, 0.0 days; 95% CI, -0.6 to 0.5; P = 0.860); the theoretical postoperative hospital length of stay was 4 ± 2 days for the plethysmographic variability index group and 4 ± 1 days for the control group (P = 0.238). In the plethysmographic variability index and control groups, serious postoperative cardiac complications occurred in 3 of 217 (1%) and 2 of 224 (1%) patients (P = 0.681), acute postoperative renal failure occurred in 9 (4%) and 8 (4%) patients (P = 0.808), the troponin Ic concentration was more than 0.06 µg/l within 5 days postoperatively for 6 (3%) and 5 (2%) patients (P = 0.768), and the postoperative arterial lactate measurements were 1.44 ± 1.01 and 1.43 ± 0.95 mmol/l (P = 0.974), respectively. CONCLUSIONS: Among intermediate-risk patients having orthopedic surgery with general anesthesia, fluid administration guided by the plethysmographic variability index did not shorten the duration of hospitalization or reduce complications.

Improving the prognostic value of ∆PCO2 following cardiac surgery: a prospective pilot study.

Conflicting results have been published on prognostic significance of central venous to arterial PCO2 difference (∆PCO2) after cardiac surgery. We compared the prognostic value of ∆PCO2 on intensive care unit (ICU) admission to an original algorithm combining ∆PCO2, ERO2 and lactate to identify different risk profiles. Additionally, we described the evolution of ∆PCO2 and its correlations with ERO2 and lactate during the first postoperative day (POD1). In this monocentre, prospective, and pilot study, 25 patients undergoing conventional cardiac surgery were included. Central venous and arterial blood gases were collected on ICU admission and at 6, 12 and 24 h postoperatively. High ∆PCO2 (≥ 6 mmHg) on ICU admission was found to be very frequent (64% of patients). Correlations between ∆PCO2 and ERO2 or lactate for POD1 values and variations were weak or non-existent. On ICU admission, a high ∆PCO2 did not predict a prolonged ICU length of stay (LOS). Conversely, a significant increase in both ICU and hospital LOS was observed in high-risk patients identified by the algorithm: 3.5 (3.0-6.3) days versus 7.0 (6.0-8.0) days (p = 0.01) and 12.0 (8.0-15.0) versus 8.0 (8.0-9.0) days (p < 0.01), respectively. An algorithm incorporating ICU admission values of ∆PCO2, ERO2 and lactate defined a high-risk profile that predicted prolonged ICU and hospital stays better than ∆PCO2 alone.

Spironolactone and perioperative atrial fibrillation occurrence in cardiac surgery patients: Rationale and design of the ALDOCURE trial.

BACKGROUND: After artery bypass grafting (CABG), the presence of perioperative AF (POAF) is associated with greater short- and long-term cardiovascular morbidity. Underlying POAF mechanisms are complex and include the presence of an arrhythmogenic substrate, cardiac fibrosis and electrical remodeling. Aldosterone is a key component in this process. We hypothesize that perioperative mineralocorticoid receptor (MR) blockade may decrease the POAF incidence in patients with a left ventricular ejection fraction (LVEF) ≥50% who are referred for CABG with or without aortic valve replacement (AVR). STUDY DESIGN: The ALDOCURE trial (NCT03551548) will be a multicenter, randomized, double-blind, placebo-controlled trial testing the superiority of a low-cost MR antagonist (MRA, spironolactone) on POAF in 1500 adults referred for on-pump elective CABG surgery with or without AVR, without any history of heart failure or atrial arrhythmia. The primary efficacy end point is the occurrence of POAF from randomization to within 5 days after surgery, assessed in a standardized manner. The main secondary efficacy end points include the following: postoperative AF occurring within 5 days after cardiac surgery, perioperative myocardial injury, major cardiovascular events and death occurring within 30 days of surgery, hospital and intensive care unit length of stay, need for readmission, LVEF at discharge and significant ventricular arrhythmias within 5 days after surgery. Safety end points, including blood pressure, serum potassium levels and renal function, will be monitored regularly throughout the trial duration. CONCLUSION: The ALDOCURE trial will assess the effectiveness of spironolactone in addition to standard therapy for reducing POAF in patients undergoing CABG. CLINICAL TRIAL REGISTRATION: NCT03551548.

Comparison of pre-oxygenation using spontaneous breathing through face mask and high-flow nasal oxygen: A randomised controlled crossover study in healthy volunteers.

BACKGROUND: High-flow nasal oxygen (HFNO) therapy has been proposed for pre-oxygenation before intubation, but the end-tidal fraction of oxygen (ETO2) obtained remains unknown. OBJECTIVE(S): To compare the ETO2 following a 3 min pre-oxygenation with HFNO and face mask. SETTING: Operating room in a primary university hospital. DESIGN: A randomised crossover study. PARTICIPANTS: Fifty healthy volunteers. INTERVENTIONS: Participants were randomly pre-oxygenated through spontaneous breathing 100% oxygen in a face mask and with HFNO (mouth closed, heated and humidified gas flow at 60 l min). In the face mask group, the ETO2 was measured continuously. In the HFNO group, the nasal cannula was quickly exchanged with a face mask while the subject held their breath at end inspiration and the ETO2 was measured after a deep expiration. The protocol ended when ETO2 reached 90% or otherwise at 6 min. MAIN OUTCOME MEASURES: The primary endpoint was the ETO2 after 3 min of pre-oxygenation. Secondary endpoints were the proportion of participants with an ETO2 at least 90% and the time until the ETO2 at least 90%. RESULTS: The ETO2 after 3 min of pre-oxygenation was 89 (2) % and 77 (12) % in the face mask and HFNO groups [difference 12% (95% confidence interval, 95% CI: 8 to 15]; P < 0.001), respectively. After 3 min of pre-oxygenation, 54 and 4% (P < 0.001) of volunteers had an ETO2 at least 90% in the face-mask and HFNO groups, respectively. After 6 min of pre-oxygenation, 96 and 46% (P < 0.001) of volunteers had an ETO2 at least 90% in the face-mask and HFNO groups, respectively. In the face mask group, the hazard ratio to achieve an ETO2 of 90% was 5.3 (95% CI: 3.2 to 8.9; P < 0.001). CONCLUSION: Our study demonstrates that pre-oxygenation with HFNO is not a reliable method of pre-oxygenation before the induction of anaesthesia. TRIAL REGISTRATION: clinical trial NCT03399695.

Changes in stroke volume during an alveolar recruitment maneuvers through a stepwise increase in positive end expiratory pressure and transient continuous positive airway pressure in anesthetized patients. A prospective observational pilot study.

BACKGROUND AND AIMS: Recruitment maneuvers may be used during anesthesia as part of perioperative protective ventilation strategy. However, the hemodynamic effect of recruitment maneuvers remain poorly documented in this setting. MATERIAL AND METHODS: This was a prospective observational study performed in operating theatre including patients scheduled for major vascular surgery. Patients were monitored with invasive arterial pressure and esophageal doppler. After induction of general anesthesia, before surgery began, preload optimization based on stroke volume (SV) variation following fluid challenge was performed. Then, an alveolar recruitment maneuver (ARM) through stepwise increase in positive end expiratory pressure (PEEP) or continuous positive airway pressure (CPAP) was performed. Hemodynamic data were noted before, during, and after the alveolar recruitment maneuver. RESULTS: ARM through stepwise increase in PEEP and CPAP were applied in 22 and 14 preload independent patients, respectively. Relative changes in SV during ARMs were significantly greater in the ARMCPAP group (-39 ± 20%) as compared to the ARMPEEP group (-15 ± 22%; P = 0.002). The difference (95% CI) in relative decrease in SV between ARMCPAP and ARMPEEP groups was -24% (-38 to -9; P = 0.001). Changes in arterial pressure, cardiac index, pulse pressure variation, peak velocity, and corrected flow time measures were not different between groups. CONCLUSION: During anesthesia, in preload independent patients, ARMs through CPAP resulted in a significantly greater decrease in SV than stepwise increase in PEEP. During anesthesia, ARM should be used cautiously.

Comparison of the Mallampati Classification in Sitting and Supine Position to Predict Difficult Tracheal Intubation: A Prospective Observational Cohort Study.

BACKGROUND: The Mallampati classification (MLPT) is normally evaluated in the sitting position. However, many patients cannot be evaluated in the sitting position for medical reasons. Thus, we compared the MLPT in sitting and supine positions in predicting difficult tracheal intubation (DTI). We hypothesized that the diagnostic accuracy of the MLPT performed in sitting and supine positions would differ. METHODS: We performed a single-center prospective observational study in adult patients who received general anesthesia and orotracheal intubation for noncardiac surgery. During the preanesthesia consultation, the MLPT in the sitting position was recorded. The day of surgery, the MLPT in the supine position and the difficulty of intubation (DTI) were recorded by an independent observer. The diagnostic performance of the MLPT for the prediction of DTI was evaluated in the sitting and supine positions through the area under the receiver operating characteristic (ROC) curve. The performance of the Naguib score in predicting DTI was calculated with the MLPT in sitting and supine positions. RESULTS: Among the 3036 patients, 157 (5.1%) had DTI. The area under the ROC curve for the MLPT in supine position (0.82 [0.78-0.84]) was greater than that for the MLPT in the sitting position (0.70 [0.66-0.75]; P < .001). The relationship between the sitting and supine MLPTs was moderate (Spearman rank correlation coefficient: 0.50; P < .001). The area under ROC curve for predicting DTI by the Naguib score calculated with the supine MLPT (0.78 [95% confidence interval, 0.74-0.82]) was greater than that for the Naguib score calculated with MLPT in the sitting position (0.69 [95% confidence interval, 0.63-0.74)]; P < .001). CONCLUSIONS: The MLPT performed in the supine position is possibly superior to that performed in the sitting position for predicting difficult intubation in adults.

Assessment of changes in blood glucose concentration with intravascular microdialysis.

Blood glucose and its variability of is a major prognostic factor associated with morbidity. We hypothesized that intravenous microdialysis incorporated in a central venous catheter (CVC) would be interchangeable with changes in blood glucose measured by the reference method using a blood gas analyzer. Microdialysis and central venous blood glucose measurements were simultaneously recorded in high-risk cardiac surgical patients. The correlation between absolute values was determined by linear regression and the Bland-Altman test for repeated measurements was used to compare bias, precision, and limits of agreement. Changes in blood glucose measurement were evaluated by four-quadrant plot and trend interchangeability methods (TIM). In the 23 patients analyzed, the CVC was used as part of standard care with no complications. The correlation coefficient for absolute values (N = 99) was R = 0.91 (P < 0.001). The bias, precision and limits of agreement were - 9.1, 17.4 and - 43.2 to 24.9 mg/dL, respectively. The concordance rate for changes in blood glucose measurements (N = 77) was 85% with the four-quadrant plot. The TIM showed that 14 (18%) changes of blood glucose measurements were uninterpretable. Among the remaining 63 (82%) interpretable changes, 23 (37%) were interchangeable, 13 (20%) were in the gray zone, and 27 (43%) were not interchangeable. Microdialysis using a CVC appears to provide imprecise absolute blood glucose values with risk of insulin misuse. Moreover, only one third of changes in blood glucose measurements were interchangeable with the reference method using the TIM.

Preload dependency determines the effects of phenylephrine on cardiac output in anaesthetised patients: A prospective observational study.

BACKGROUND: Although phenylephrine is widely used in the operating room to control arterial pressure, its haemodynamic effects remain controversial. OBJECTIVE: We hypothesised that the effect of phenylephrine on cardiac output is affected by preload dependency. DESIGN: A prospective observational study. SETTING: Single-centre, University Hospital of Caen, France. PATIENTS: Fifty ventilated patients undergoing surgery were studied during hypotension before and after administration of phenylephrine. MAIN OUTCOME MEASURES: Cardiac index (CI), stroke volume (SV), corrected flow time, mean arterial pressure, pulse pressure variations (PPV) and systemic vascular resistance index were used to assess effects of changes in preload dependency. RESULTS: Twenty seven (54%) patients were included in the preload-dependent group (PPV ≥ 13%) and 23 (46%) in the preload-independent group (PPV < 13%) before administration of phenylephrine. For the whole cohort, phenylephrine increased mean arterial pressure [58 (±8) mmHg vs. 79 (±13) mmHg; P < 0.0001] and calculated systemic vascular resistance index [2010 (1338; 2481) dyn s cm m vs. 2989 (2155; 3870) dyn s cm m; P < 0.0001]. However, CI and SV decreased in the preload-independent group [2.3 (1.9; 3.7) l min m vs. 1.8 (1.5; 2.7) l min m; P < 0.0001 and 65 (44; 81) ml vs. 56 (39; 66) ml; P < 0.0001 for both] but not in the preload-dependent group [respectively 2.1 (1.8; 3.5) l min m vs. 2.1 (1.8; 3.3) l min m; P = 0.168 and 49 (41; 67) ml vs. 53 (41; 69) ml; P = 0.191]. Corrected flow time increased [294 (47) ms vs. 306 (56) ms; P = 0.031], and PPV decreased [17 (15; 19) % vs.12 (14; 16) %; P < 0.0003] only in the PPV at least 13% group. CONCLUSION: The effects of phenylephrine on CI and SV depend on preload. CI and SV decreased in preload-independent patients through increase in afterload, but were unchanged in those preload-dependent through increased venous return.