Effect of Oral Carbohydrate Intake During Labor on the Rate of Instrumental Vaginal Delivery: A Multicenter, Randomized Controlled Trial.

BACKGROUND: Carbohydrate intake during physical exercise improves muscle performance and decreases fatigue. We hypothesized that carbohydrate intake during labor, which is a period of significant physical activity, can decrease the instrumental vaginal delivery rate. METHODS: In a multicenter, prospective, randomized, controlled trial, healthy adult pregnant women presenting with spontaneous labor were assigned to a "Carbohydrate" group (advised to drink 200 mL of apple or grape juice without pulp every 3 hours) or a "Fasting" group (water only). The primary outcome was the instrumental vaginal delivery rate. Secondary outcomes included duration of labor, rate of cesarean delivery, evaluation of maternal hunger, thirst, stress, fatigue, and overall feeling during labor by numeric rating scale (0 worst rating to 10 best rating), rate of vomiting, and hospital length of stay. Statistical analysis was performed on an intention-to-treat basis. The primary outcome was tested with the "Fasting" group as the reference group. The P values for secondary outcomes were adjusted for multiple comparisons. The differences between groups are reported with 99% confidence interval (CI). RESULTS: A total of 3984 women were analyzed (2014 in the Carbohydrate group and 1970 in the Fasting group). There was no difference in the rate of instrumental delivery between the Carbohydrate (21.0%) and the Fasting (22.4%) groups (difference, -1.4%; 99% CI, -4.9 to 2.2). No differences were found between the Carbohydrate and the Fasting groups for the duration of labor (difference, -7 minutes; 99% CI, -25 to 11), the rate of cesarean delivery (difference, -0.3%; 99% CI, -2.4 to 3.0), the rate of vomiting (difference, 2.8%; 99% CI, 0.2-5.7), the degree of self-reported fatigue (difference, 1; 99% CI, 0-2), self-reported hunger (difference, 0; 99% CI, -1 to 1), thirst (difference, 0; 99% CI, -1 to 1), stress (difference, 0; 99% CI, -1 to 1), overall feeling (difference, 0; 99% CI, 0-0), and the length of hospitalization (difference, 0; 99% CI, -1 to 0). CONCLUSIONS: Carbohydrate intake during labor did not modify the rate of instrumental vaginal delivery.

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.

Impact of a feedback device on chest compression quality during extended manikin CPR: a randomized crossover study.

PURPOSES: Chest compressions require physical effort leading to increased fatigue and rapid degradation in the quality of cardiopulmonary resuscitation overtime. Despite harmful effect of interrupting chest compressions, current guidelines recommend that rescuers switch every 2 minutes. The impact on the quality of chest compressions during extended cardiopulmonary resuscitation has yet to be assessed. BASIC PROCEDURES: We conducted randomized crossover study on manikin (ResusciAnne; Laerdal). After randomization, 60 professional emergency rescuers performed 2 × 10 minutes of continuous chest compressions with and without a feedback device (CPRmeter). Efficient compression rate (primary outcome) was defined as the frequency target reached along with depth and leaning at the same time (recorded continuously). MAIN FINDINGS: The 10-minute mean efficient compression rate was significantly better in the feedback group: 42% vs 21% (P< .001). There was no significant difference between the first (43%) and the tenth minute (36%; P= .068) with feedback. Conversely, a significant difference was evident from the second minute without feedback (35% initially vs 27%; P< .001). The efficient compression rate difference with and without feedback was significant every minute, from the second minute onwards. CPRmeter feedback significantly improved chest compression depth from the first minute, leaning from the second minute and rate from the third minute. PRINCIPAL CONCLUSIONS: A real-time feedback device delivers longer effective, steadier chest compressions over time. An extrapolation of these results from simulation may allow rescuer switches to be carried out beyond the currently recommended 2 minutes when a feedback device is used.

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.

The impact of an algorithm on the optimization of beta-blockers after cardiac surgery.

OBJECTIVE: To evaluate the impact of a simple written algorithm of early postoperative beta-blocker administration on daily practices. DESIGN: A prospective, single center observational study. SETTING: A 16-bed cardiac surgical intensive care unit in a university teaching hospital. PATIENTS: One hundred twenty-five consecutive adult patients chronically treated with beta-blockers and scheduled for conventional cardiac surgery. INTERVENTIONS: Two successive 4-month phases: Phase 1 = uncontrolled early postoperative beta-blocker administration (n = 73) and phase 2 = beta-blocker administration by an institutional written algorithm using incremental doses of bisoprolol and/or esmolol (n = 52). MEASUREMENTS AND MAIN RESULTS: The main endpoint was the number of patients receiving beta-blockers on the morning of postoperative day 1. Secondary endpoints were the number of patients receiving beta-blockers on the morning of postoperative day 1 and reaching the targeted therapeutic goal and the incidence of postoperative atrial fibrillation in the intensive care unit. A 79% increase in the number of patients receiving beta-blockers on the morning of postoperative day 1 (42% v 75%, p<0.001) was observed during the second phase of the study. The number of patients receiving beta-blockers on the morning of postoperative day 1 and reaching the targeted therapeutic goal was increased significantly by 127% (33% v 75%, p<0.001). The incidence of atrial fibrillation was similar between both phases of the study: 37% versus 31%, p = 0.567. CONCLUSIONS: A simple written algorithm markedly improved early postoperative continuation of beta-blockers in chronically treated patients undergoing conventional cardiac surgery.

Near-Infrared Spectroscopy Hemoglobin Index Measurement During Fluid Challenge: A Prospective Study in Cardiac Surgery Patients.

OBJECTIVE: Little is known about changes in near-infrared spectroscopy-derived tissue hemoglobin index (HbI). The authors tested the hypothesis that absolute values and changes in brain hemoglobin index (HbIb) and skeletal muscle hemoglobin index (HbIm) could differ from the reference arterial hemoglobin (Hb) during fluid challenge. DESIGN: A prospective, monocenter observational study. SETTING: A 16-bed cardiac surgical intensive care unit in a teaching university hospital. PARTICIPANTS: Fifty consecutive adult patients. INTERVENTIONS: Investigation before and after a fluid challenge. MEASUREMENTS AND MAIN RESULTS: Simultaneous comparative Hb, HbIb and HbIm data points were collected from a blood-gas analyzer and the EQUANOX device (Nonin Medical Inc., Plymouth, MN). Correlations were determined by linear regression. No significant relationship was found between absolute values of Hb and HbIb before (R(2)= 0.04, p = 0.627) and after (R(2) = 0.00006, p = 0.956) fluid challenge. No significant relationship was found between absolute values of Hb and HbIm before (R(2)= 0.030, p = 0.226) and after (R(2) = 0.05, p = 0.117) the fluid challenge. No significant relationship was found between changes in Hb and HbIb (R(2)= 0.26, p = 0.263) and between changes in Hb and HbIm (R(2) = 0.001, p = 0.801) after the fluid challenge. Bland-Altman analysis showed a poor concordance between changes in Hb and HbIb, and changes in Hb and HbIm, with large limits of agreement. CONCLUSIONS: HbIb and HbIm cannot be used to provide continuous noninvasive estimation of Hb, and trends in HbIb and HbIm cannot be considered as noninvasive surrogates for the trend in Hb after cardiac surgery.

Preoxygenation by spontaneous breathing or noninvasive positive pressure ventilation with and without positive end-expiratory pressure: A randomised controlled trial.

BACKGROUND: In emergency situations requiring rapid airway control, shortening preoxygenate time is desirable. OBJECTIVES: The objective of this study is to compare the time to achieve an expired O2 fraction FeO2 of 90% (FeO2 90%) during preoxygenation with spontaneous breathing and positive pressure ventilation with and without positive end-expiratory pressure (PEEP). DESIGN: A randomised controlled trial. SETTING: Primary care in a university hospital in France from October 2006 to January 2008. PATIENTS: Adults patients scheduled for elective surgery. Exclusion criteria were rapid sequence induction, anticipated difficult airway management and refusal to provide consent. INTERVENTION: Patients were randomly allocated to preoxygenation with spontaneous breathing or positive pressure ventilation (positive inspiratory pressure: 12 cmH2O) without PEEP and with PEEP (positive inspiratory pressure: 12 cmH2O, PEEP: 6 cmH2O). MAIN OUTCOME MEASURES: Time to achieve an expired O2 fraction of 90% measured from positioning the face mask, and the time it took after endotracheal intubation for the SpO2 to fall to 93% (SpO2 93%) while the patient was apnoeic. Patient discomfort was recorded (visual analogue scale). Data are median (quartile 25th to 75). RESULTS: The time to achieve an FeO2 90% was shorter with positive pressure ventilation, with PEEP [140 (100 to 200) s] and without PEEP [153 (120 to 218) s], than with spontaneous breathing [190 (130 to 264) s; P = 0.002]. At 3 in, 47, 60 and 74% of patients achieved an FeO2 of 90% or more in the spontaneous breathing, positive pressure ventilation without and with PEEP groups, respectively (P = 0.01). Cox proportional-hazards regression showed that positive pressure ventilation with PEEP [hazard ratio 2.18; 95% confidence interval (95% CI) 1.42 to 3.36); P < 0.001] and without PEEP (hazard ratio 1.62; 95% CI 1.05 to 2.50; P = 0.03) were associated with a shorter time to an FeO2 90%. The time until SpO2 93% was not significantly different between spontaneous breathing [305 (263 to 383) s], positive pressure ventilation without PEEP [370 (300 to 450) s] and with PEEP [345 (245 to 435) s; P = 0.08]. The discomfort reported was 0 (0 to 18) mm and was comparable between groups (P = 0.22). CONCLUSION: Compared with spontaneous breathing, positive pressure ventilation with and without PEEP shortened preoxygenation time. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02313766.

Noninvasive assessment of peripheral microcirculation by near-infrared spectroscopy: a comparative study in healthy smoking and nonsmoking volunteers.

Smokers are exposed to early endothelial dysfunction. This microcirculatory damage can be demonstrated by near-infrared spectroscopy (NIRS). The aim of this study was to compare microvascular reactivity by NIRS during a dynamic vascular occlusion test in healthy smokers and nonsmokers volunteers. Twenty healthy volunteers (10 men, 10 women), aged from 22 to 38 years old, were included after approval of the local Ethics Committee and divided into two groups: smokers (n = 10) and nonsmokers (n = 10). Tissue oxygen saturation (StO2) was measured at the level of each individual's calves during an ischemia and reperfusion test. In addition, during the ischemia phase, the slope of decline in StO2 was determined. Therefore, for each group, we were able to deduce the speed of desaturation (ΔStO2/ischemia time). The same was applied for resaturation rates during the reperfusion phase (ΔStO2/reperfusion time). StO2 values were comparable at all experimental steps between smokers and nonsmokers. During the vascular occlusion test, rates of desaturation were the same between smokers and nonsmokers [respectively 3.7%·min(-1) (range 2.5-12.6) and 3.7%·min(-1) (range 1.8-15.1); p = 0.50]. It was the same for the rate of resaturation [smokers 30.4%·min(-1) (range 14.2-51.6) and nonsmokers 30.5%·min(-1) (range 18.6-44.5); p = 0.82]. NIRS study of microvascular reactivity during a dynamic vascular occlusion test did not reveal any difference between smokers and nonsmokers. Therefore, NIRS could not be sensitive enough to highlight endothelial dysfunction in healthy subjects exposed to tobacco smoke.

Early goal-directed therapy based on endotracheal bioimpedance cardiography: a prospective, randomized controlled study in coronary surgery.

The objective was to compare the impact of an early goal-directed hemodynamic therapy based on cardiac output monitoring (Endotracheal Cardiac Output Monitor, ECOM) with a standard of care on postoperative outcome following coronary surgery. This prospective, controlled, parallel-arm trial randomized 100 elective primary coronary artery bypass grafting patients to a study group (ECOM; n = 50) or a control group (control; n = 50). In the ECOM group, hemodynamic therapy was guided by respiratory stroke volume variation and cardiac index given by the ECOM system. A standard of care was used in the control. Goal-directed therapy was started immediately after induction of anesthesia and continued until arrival in the intensive care unit (ICU). The primary endpoint was the time when patients fulfilled discharge criteria from hospital (possible hospital discharge). Secondary endpoints were the hospital discharge, the time to reach extubation, the length of stay in ICU, the number of major adverse cardiac events, and in-hospital mortality. Patients in the ECOM group received more often fluid loading and dobutamine. The time to reach extubation was reduced in the ECOM group: 510 min [360-1,110] versus 570 min [320-1,520], P = 0.005. No significant differences were found between both groups for possible hospital discharge [Hazard Ratio = 0.96 (95 % CI 0.64-1.45)] and hospital discharge [Hazard Ratio = 1.20 (95 % CI 0.79-1.81)]. A mini-invasive early goal-directed hemodynamic therapy based on ECOM can reduce the time to reach extubation but fails to significantly reduce the length of stay in hospital and the rate of major cardiac morbidity.

The diagnostic accuracy of estimated continuous cardiac output compared with transthoracic echocardiography.

PURPOSE: Estimated continuous cardiac output (esCCO) is a new and noninvasive cardiac output (CO) monitoring device using pulse wave transit time. The aim of this study was to assess rapid changes in CO using esCCO (ΔCOesCCO) without invasive calibration and to compare the results with those using transthoracic Doppler echocardiography (ΔCOTTE). METHODS: Fifty-four consecutive patients were enrolled in this study following elective cardiac surgery. The COesCCO and COTTE were collected during four consecutive steps: 1) at baseline, 2) during passive leg raising (PLR), 3) at return to baseline, and 4) after a fluid challenge. The relationship between ΔCOesCCO and ΔCOTTE induced by PLR and a fluid challenge was assessed and a polar plot analysis was performed. Relationship, Bland-Altman analysis, and percentage error for absolute values of COesCCO and COTTE were also performed. RESULTS: Twenty-four patients were excluded from the analysis. No correlation was found between ΔCOesCCO and ΔCOTTE during PLR (r = 0.07; P = 0.732; n = 30) and after a fluid challenge (r = 0.24; P = 0.394; n = 14). The polar plot analysis showed that 21 data points (87%) of significant changes in CO were above the 30° radial sector lines and confirmed that esCCO was unable to track changes in CO. A weak positive relationship was found between absolute values of COesCCO and COTTE (r = 0.28; P = 0.004). Bias, precision, and limits of agreement were 0.25 L·min(-1), 2.4 L·min(-1), and -4.4 to 4.9 L·min(-1), respectively. The percentage error was 80%. CONCLUSIONS: Estimated continuous cardiac output without external calibration seems unable to assess rapid changes in CO following cardiac surgery and was not interchangeable with transthoracic Doppler echocardiography.

Cephalic versus digital plethysmographic variability index measurement: a comparative pilot study in cardiac surgery patients.

OBJECTIVES: Noninvasive measurement of digital plethysmographic variability index (PVI(digital)) has been proposed to predict fluid responsiveness, with conflicting results. The authors tested the hypothesis that cephalic sites of PVI measurement (namely PVI(ear) and PVI(forehead)) could be more discriminant than PVI(digital) to predict fluid responsiveness after cardiac surgery. DESIGN: A prospective observational study. SETTING: A cardiac surgical intensive care unit of a university hospital. PARTICIPANTS: Fifty adult patients. INTERVENTIONS: Investigation before and after fluid challenge. MEASUREMENT AND MAIN RESULTS: Patients were prospectively included within the first 6-hour postoperative period and investigated before and after fluid challenge. A positive response to fluid challenge was defined as a 15% increase in cardiac index. PVI(digital), PVI(ear), PVI(forehead), and invasive arterial pulse-pressure variation (PPV) measurements were recorded simultaneously, and receiver operating characteristic (ROC) curves were built. Forty-one (82%) patients were responders and 9 (18%) patients were nonresponders to fluid challenge. ROCAUC were 0.74 (95% confidence interval [95% CI]: 0.60-0.86), 0.81 (95% CI: 0.68-0.91), 0.88 (95% CI: 0.75-0.95) and 0.87 (95% CI: 0.75-0.95) for PVI(digital), PVI(ear), PVI(forehead), and PPV, respectively. Significant differences were observed between PVI(forehead) and PVI(digital) (absolute difference in ROCAUC = 0.134 [95% CI: 0.003-0.265], p = 0.045) and between PPV and PVI(digital) (absolute difference in ROCAUC = 0.129 [95% CI: 0.011-0.247], p = 0.033). The percentage of patients within the inconclusive class of response was 46%, 70%, 44%, and 26% for PVI(digital), PVI(ear), PVI(forehead), and PPV, respectively. CONCLUSIONS: PVI(forehead) was more discriminant than PVI(digital) and could be a valuable alternative to arterial PPV in predicting fluid responsiveness.

Improvement in chest compression quality using a feedback device (CPRmeter): a simulation randomized crossover study.

PURPOSES: Cardiac arrest survival depends on celerity and efficiency of life support action. Guidelines emphasized the chest compression (CC) quality and feedback devices are encouraged. The purpose is to study the impact of the CPRmeter feedback device on resuscitation performed by untrained rescuers. BASIC PROCEDURES: This is a prospective randomized crossover study on manikins (Resusci Anne). One hundred and forty four students inexperienced in cardiopulmonary resuscitation representing untrained rescuers were included. Participants performed 2 minutes of CC without interruption with (group G) or without (group B) feedback. Four months passed between the 2 crossover phases to avoid resilience effect. Data collected by the CPRmeter device were: CC rate, depth and release. MAIN FINDINGS: Efficient CC rate ([simultaneous and correct CC rate, depth and release] primary outcome) (absolute difference [95% CI]) was significantly improved in group G (71%) compared to group B (26%; [45 {36-55}]; P < .0001). Adequate depth rate (>38 mm) was significantly improved in group G (85%) compared to group B (43%; [42 {33-52}]; P < .0001). Adequate CC rate (90-120/min) was significantly improved in group G (81%) compared to group B (56%; [25 {15-35}]; P < .0001). The average CC rate and depth in group G were significantly less dispersed around the mean compared to group B (test of variance P < .007; P < .015 respectively). PRINCIPAL CONCLUSIONS: The use of the CPRmeter significantly improved CC quality performed by students inexperienced in cardiopulmonary resuscitation.

Prediction of responsiveness to an intravenous fluid challenge in patients after cardiac surgery with cardiopulmonary bypass: a comparison between arterial pulse pressure variation and digital plethysmographic variability index.

OBJECTIVES: Arterial pulse pressure variation (PPV) and digital plethysmographic variability index (PVI) have been proposed to predict fluid responsiveness during anesthesia and in critically ill patients. The present study aimed to compare the clinical utility of PPV and PVI in predicting fluid responsiveness after elective cardiac surgery. DESIGN: A prospective observational study. SETTING: A university hospital. PARTICIPANTS: Eighty-seven adult patients. INTERVENTIONS: Admission to the intensive care unit after cardiac surgery. Investigation before and after fluid challenge. MEASUREMENTS AND MAIN RESULTS: The discrimination of both PPV and PVI in predicting fluid responsiveness was compared by using areas under the receiver operating characteristics curves (ROCAUC). Sensibility analyses were conducted after exclusion of patients with a low perfusion index, patients receiving norepinephrine, and patients with right ventricular dysfunction. Fifty-seven (71%) patients were responders and twenty-three (29%) were nonresponders. ROCAUC were 0.73 [95% CI: 0.63-0.83] versus 0.60 [95% CI: 0.48-0.71] for PPV and PVI in the whole cohort of patients, respectively (p = 0.020). The inconclusive class of responses included 47 (59%) and 62 (77%) patients, respectively (p = 0.010); whereas the discrimination of PVI remained low whatever the subgroup of patients, the discrimination of PPV markedly increased in patients without perfusion index ≤ 1.3 (ROCAUC = 0.83 [95% CI: 0.68-0.93]) and in patients without right ventricular dysfunction (ROCAUC = 0.85 [95% CI: 0.67-0.95]). CONCLUSIONS: PVI is not discriminant and probably inaccurate to predict fluid responsiveness after elective cardiac surgery. PPV could be of potential interest after exclusion of patients with a low perfusion index and right ventricular dysfunction.

Cerebral and somatic near-infrared spectroscopy measurements during fluid challenge in cardiac surgery patients: a descriptive pilot study.

OBJECTIVE: Little is known about changes in near-infrared spectroscopy (NIRS)-derived cerebral (rSO(2)b) and somatic (rSO(2)s) oxygen saturation during a fluid challenge. The authors tested the hypothesis that they could differ from central venous oxygen saturation (ScvO(2)) and from one site to another. DESIGN: A prospective observational study. SETTING: A teaching university hospital. PARTICIPANTS: Fifty consecutive adult patients. INTERVENTIONS: Admission to the intensive care unit after cardiac surgery and investigation before and after a fluid challenge. MEASUREMENTS AND MAIN RESULTS: Simultaneous comparative ScvO(2), rSO(2)b, and rSO(2)s data points were collected from a blood-gas analyzer and the EQUANOX monitor (Nonin Medical, Inc, Plymouth, MN). Correlations were determined by linear regression. Multiple stepwise linear regression models were used to assess independent variables associated with changes in ScvO(2), rSO(2)b, and rSO(2)s. A statistically significant relationship was found between absolute values of ScvO(2) and rSO(2)b (r = 0.42, p < 0.001) but not between absolute values of ScvO(2) and rSO(2)s (r = 0.18, p = 0.066). No relationship was found between percent changes in ScvO(2) and rSO(2)b (r = 0.05, p = 0.715) and between percent changes in ScvO(2) and rSO(2)s (r = 0.02, p = 0.886) after the fluid challenge. Cardiac index contributed to the prediction of changes in ScvO(2) (regression coefficient = -4.09, p = 0.006), whereas the mean arterial pressure contributed to the prediction of changes in rSO(2)b (regression coefficient = -0.05, p = 0.027). CONCLUSIONS: rSO(2)b and rSO(2)s cannot be used to provide noninvasive estimation of ScvO(2), and trends in rSO(2)b and rSO(2)s cannot be considered as noninvasive surrogates for the trend in ScvO(2) after cardiac surgery. Different independent variables contribute to the prediction of ScvO(2), rSO(2)b, and rSO(2)s.

Comparison of plastic and metallic single-use and metallic reusable laryngoscope blades: a randomised controlled trial.

CONTEXT: Plastic single-use laryngoscope blades have been found to increase the difficulty of intubation. Metallic single-use blades may represent an alternative. OBJECTIVE: To compare the rates of intubation failure at first laryngoscopy using metallic single-use, plastic single-use and metallic reusable laryngoscope blades. DESIGN: Randomised, superiority, single-centre, controlled trial. SETTING: Operating theatres at a University Hospital from January 2008 to August 2009. PATIENTS: A total of 1863 adults requiring general anaesthesia. INTERVENTION: Patients were randomised to one of three laryngoscope blades: metallic single-use, plastic single-use or metallic reusable. MAIN OUTCOME MEASURE: The primary end-point was the number of intubation failures at first laryngoscopy. Secondary end-points were glottic exposure and the Intubation Difficulty Scale. RESULTS: The failure rate (absolute difference: 95% confidence interval) at the first attempt was greater for the plastic single-use blades (8.1%) than for the metallic reusable [3.2% (4.9%: 2.2 to 7.6%); P < 0.001] and metallic reusable blades [4.0% (4.0%: 1.2 to 6.9%); P < 0.006]. No difference was found between the metallic reusable and metallic single-use groups (0.9%: -1.3 to 3.1%). Scoring on the Intubation Difficulty Scale [median (interquartile range)] was higher in the plastic single-use group [1 (0 to 2)] than in the metallic groups [metallic reusable: 0 (0 to 1); P < 0.001 and metallic single-use: 0 (0 to 1); P < 0.007] groups. Glottic exposure was significantly better in the metallic reusable group (modified Cormack & Lehane score III and IV: 3.7%) compared with the plastic single-use group (modified Cormack & Lehane score III and IV: 9.4%; P < 0.03). CONCLUSION: The rates of failed intubation at first laryngoscopy were similar in the metallic reusable and metallic reusable groups, but greater in the plastic single-use group.

Mechanisms involved in cardioprotective effects of pravastatin administered during reoxygenation in human myocardium in vitro.

BACKGROUND: The authors investigated the effect of pravastatin during reoxygenation after myocardial hypoxia and examined the involvement of nitric oxide synthase, mitochondrial permeability transition pore, and expression of markers of apoptosis in human myocardium in vitro. METHODS: Human atrial trabeculae were exposed to hypoxia for 30 min and reoxygenation for 60 min (control group; n = 10). Pravastatin (5, 10, 50, 75 µM; n = 6 in each group) was administered throughout the reoxygenation. In separate groups (n = 6 in each group), pravastatin 50 µM was administered in the presence of 200 µM L-NG-nitroarginine methyl ester, a nitric oxide synthase inhibitor, and 50 µM atractyloside, the mitochondrial permeability transition pore opener. The primary endpoint was the developed force of contraction at the end of reoxygenation, expressed as a percentage of baseline (mean ± SD). Protein expression of BAD, phospho-BAD, caspase 3, Pim-1 kinase, and Bcl-2 were measured using Western immunoblotting. RESULTS: The administration of 10 (77 ± 5% of baseline), 50 (86 ± 6%), and 75 µM (88 ± 13%) pravastatin improved the force of contraction at the end of reoxygenation, compared with that of the control group (49 ± 11%; P < 0.001). These beneficial effects were prevented by L-NG-nitroarginine methyl ester and atractyloside. Compared with control group, the administration of 5 µM pravastatin did not modify the force of contraction. Pravastatin increased the phosphorylation of BAD, activated the expression of Pim-1 kinase and Bcl-2, and maintained the caspase 3 concentration relative to that of the respective untreated controls. CONCLUSIONS: Pravastatin, administered at reoxygenation, protected the human myocardium by preventing the mitochondrial permeability transition pore opening, phosphorylating BAD, activating nitric oxide synthase, Pim-1 kinase, and Bcl-2, and preserving the myocardium against the caspase 3 activation.

The prognostic value of B-type natriuretic peptide after cardiac surgery: a comparative study between coronary artery bypass graft surgery and aortic valve replacement.

OBJECTIVES: The influence of the cardiac surgical procedure on B-type natriuretic peptide (BNP) for the identification of high-risk patients has not been evaluated. This study aimed to compare the prognostic utility of pre- and postoperative BNP in predicting adverse long-term outcome after coronary artery bypass graft (CABG) surgery and aortic valve replacement (AVR). DESIGN: A retrospective study. SETTING: A university teaching hospital. PARTICIPANTS: One hundred eighty-nine patients. MEASUREMENTS AND MAIN RESULTS: Preoperative, early postoperative (24 hours), and late postoperative (day 5) BNP levels were measured. Major adverse cardiac events (MACEs) within 12 months after surgery were chosen as study endpoints. The predictive abilities of BNP measurements were compared using receiver operating characteristic (ROC) curves. Patients were stratified by CABG surgery (n = 100) and AVR (n = 89). Thirty-four (18%) patients experienced 44 MACEs over the study period. Preoperative BNP values were significantly different between groups. Postoperative BNP gradually increased by 431% on day 5 after CABG surgery and by 100% after AVR (both p < 0.001 v preoperative values). Pre- and early postoperative BNP values were accurate in predicting MACEs after AVR (areas under the ROC curves: 0.78 [95% confidence interval, 0.66-0.90] and 0.76 [95% confidence interval, 0.62-0.89], respectively) and inaccurate after CABG surgery (0.54 [95% confidence interval, 0.38-0.70] and 0.54 [95% confidence interval, 0.36-0.73], respectively). The late postoperative BNP value was of limited value. CONCLUSIONS: BNP measurements should take into account the type of cardiac surgery. Whatever the time of measurement, BNP accurately predicts long-term adverse outcome in valve surgery patients. A late postoperative BNP measurement is useless after cardiac surgery.