Prevalence and time-course of diaphragmatic dysfunction following lung resection: A repeated ultrasonic assessment.

PURPOSE: Ultrasound (US) allows non-invasive repeated assessments of diaphragmatic excursion (DE) and thickening fraction (DTF) at the bedside, reflecting diaphragmatic dysfunction (DD). We aimed at determining the prevalence and time-course of DD following elective thoracic surgery and the association with postoperative complications. MATERIAL AND METHODS: Prospective, single-centre, observational study with consecutive patients undergoing thoracic surgery. DE/DTF were measured by two observers blinded to each other at 3 different time-points: prior to surgery, immediately after extubation and on postoperative day 3. The changes in DE/DTF of both hemi-diaphragms over time were compared according to the side (operated/non-operated) using a two-way-ANOVA. The association with postoperative complications was assessed using logistic regression. RESULTS: Fifty patients, 60% males, aged 60 ± 15 years were included. Surgical procedures included lobectomy (n = 30), wedge-resection (n = 17) or pneumonectomy (n = 3). On the operated side, we observed a decrease in DE/DTF at D0 (-0.71 ± 0.12 mm, P < 0.05; -44 ± 30%, P < 0.05) and D3 (-0.82 ± 0.19 mm, P < 0.05; -39 ± 19%, P < 0.05) with respect to preoperative and non-operated side values over the study period. Persistent DD on the operated side was associated with an increased risk of lung infection (OR: 9.0, 95% CI [1.92-65.93], P = 0.001), ICU-admission (OR: 3.9, 95% CI [1.10-15.53], P = 0.04) according to univariate analysis and a prolonged length in hospital (OR: 1.3, 95% CI [1.1-1.7], P = 0.016) according to multivariate analysis. CONCLUSIONS: Thoracic surgery generates DD mainly observed on the operated side, which persists at least up to postoperative D3 and is associated with an increase in hospital stay.

Effect of open-lung vs conventional perioperative ventilation strategies on postoperative pulmonary complications after on-pump cardiac surgery: the PROVECS randomized clinical trial.

PURPOSE: To evaluate whether a perioperative open-lung ventilation strategy prevents postoperative pulmonary complications after elective on-pump cardiac surgery. METHODS: In a pragmatic, randomized, multicenter, controlled trial, we assigned patients planned for on-pump cardiac surgery to either a conventional ventilation strategy with no ventilation during cardiopulmonary bypass (CPB) and lower perioperative positive end-expiratory pressure (PEEP) levels (2 cm H2O) or an open-lung ventilation strategy that included maintaining ventilation during CPB along with perioperative recruitment maneuvers and higher PEEP levels (8 cm H2O). All study patients were ventilated with low-tidal volumes before and after CPB (6 to 8 ml/kg of predicted body weight). The primary end point was a composite of pulmonary complications occurring within the first 7 postoperative days. RESULTS: Among 493 randomized patients, 488 completed the study (mean age, 65.7 years; 360 (73.7%) men; 230 (47.1%) underwent isolated valve surgery). Postoperative pulmonary complications occurred in 133 of 243 patients (54.7%) assigned to open-lung ventilation and in 145 of 245 patients (59.2%) assigned to conventional ventilation (p = 0.32). Open-lung ventilation did not significantly reduce the use of high-flow nasal oxygenotherapy (8.6% vs 9.4%; p = 0.77), non-invasive ventilation (13.2% vs 15.5%; p = 0.46) or new invasive mechanical ventilation (0.8% vs 2.4%, p = 0.28). Mean alive ICU-free days at postoperative day 7 was 4.4 ± 1.3 days in the open-lung group vs 4.3 ± 1.3 days in the conventional group (mean difference, 0.1 ± 0.1 day, p = 0.51). Extra-pulmonary complications and adverse events did not significantly differ between groups. CONCLUSIONS: A perioperative open-lung ventilation including ventilation during CPB does not reduce the incidence of postoperative pulmonary complications as compared with usual care. This finding does not support the use of such a strategy in patients undergoing on-pump cardiac surgery. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT02866578. https://clinicaltrials.gov/ct2/show/NCT02866578.

Real-Time and Non-invasive Monitoring of the Activation of the IRE1α-XBP1 Pathway in Individuals with Hemodynamic Impairment.

Many stressors that are encountered upon kidney injury are likely to trigger endoplasmic reticulum (ER) stress, subsequently activating transcriptional, translational and metabolic reprogramming. Monitoring early cellular adaptive responses engaged after hemodynamic impairment yields may represent a clinically relevant approach. However, a non-invasive method for detecting the ER stress response has not been developed. We combined a metabolomic approach with genetic marker analyses using urine from individuals undergoing scheduled cardiac surgery under cardiopulmonary bypass to investigate the feasibility and significance of monitoring the ER stress response in the kidney. We developed an original method based on fragment analysis that measures urinary levels of the spliced X-box binding protein 1 (sXBP1) mRNA as a proxy of inositol-requiring enzyme 1α (IRE1α) activity because sXBP1 is absolutely sensitive and specific for ER stress. The early engagement of the ER stress response after ischemic stress is critical for protecting against tissue damage, and individuals who mount a robust adaptive response are protected against AKI. The clinical consequences of our findings are of considerable importance because ER stress is involved in numerous conditions that lead to AKI and chronic kidney disease; in addition, the detection of ER stress is straightforward and immediately available in routine practice.

Determinants of Transcutaneous Ear Lobe CO2 Tension (PtCO2) at 37°C During On-Pump Cardiac Surgery.

OBJECTIVE: There are no available criteria for determining the optimal flow rate and mean arterial pressure level in patients undergoing cardiopulmonary bypass (CPB). Transcutaneous carbon dioxide tension (PtCO2) has been proposed for microcirculation monitoring and it could be useful for guiding hemodynamic optimization under CPB. The goal of this exploratory study was to determine the factors that influence PtCO2 variations during CPB. DESIGN: Cutaneous ear lobe CO2 tension was monitored along with hemodynamic parameters every 10 minutes during CPB, until aortic unclamping. SETTING: French university teaching hospital. PARTICIPANTS: Patients scheduled for cardiac surgery requiring CPB were prospectively included. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: A total of 41 patients were included (520 observations). There was a statistically significant association between PaCO2 and PtCO2 (beta = 0.493 [0.154-0.832], p = 0.043), mostly when PaCO2 was outside the normal range. When PaCO2 was normal, PtCO2 was inversely correlated with mean arterial pressure (after adjustment for PaCO2 and body temperature: Beta -0.245, SE = 0.037, p<0.001) but not with CPB flow rate (p = 0.11). CONCLUSION: The factors that influence PtCO2 during CPB cardiac surgery are PaCO2, body temperature, and mean arterial pressure. When PaCO2 is normal, a PtCO2 elevation might be explained by insufficient mean arterial pressure. Whether low PtCO2 values during CPB should trigger the administration of vasoconstrictors remains to be evaluated.

Combination of dexamethasone and local anaesthetic solution in peripheral nerve blocks: A meta-analysis of randomised controlled trials.

BACKGROUND: Dexamethasone decreases postoperative pain and prolongs the duration of local anaesthetic peripheral nerve blocks in studies including a limited number of patients. OBJECTIVE: The objective of this study is to evaluate the effect of combining dexamethasone with local anaesthetic on sensory and motor peripheral nerve blockade in adults. DESIGN: A systematic review with meta-analysis of randomised controlled trials. DATA SOURCES: We systematically searched in Medline, Embase, Google Scholar and Cochrane Controlled Trials Register up to December 2013. ELIGIBILITY CRITERIA: Randomised trials testing dexamethasone combined with local anaesthetic. RESULTS: Twelve trials (1054 patients, 512 receiving perineural dexamethasone) were included. Ten studies evaluated dexamethasone for brachial plexus nerve block. Four to 10 mg dexamethasone-containing local anaesthetic solutions had a faster onset of action and resulted in a significant increase in the duration of analgesia [weighted mean difference (WMD) 351 min, 95% confidence interval (95% CI) 288 to 413, P < 0.001] and motor blockade (WMD 277 min, 95% CI 167 to 387, P < 0.001) compared with local anaesthetic solutions alone. Time to onset of sensory and motor blocks was significantly reduced with dexamethasone (WMD -78 s, 95% CI -112 to -44, and -90 s, 95% CI -131 to -48, respectively). Dexamethasone significantly decreased postoperative nausea and vomiting (PONV, 9 vs. 27%, relative risk 0.36, 95% CI 0.19 to 0.70). Subgroup analyses showed that dexamethasone approximately doubled the duration of postoperative analgesia when it was combined with intermediate-acting (lidocaine, mepivacaine) or long-acting (bupivacaine, ropivacaine) local anaesthetics. CONCLUSION: Combining dexamethasone with local anaesthetics results in a prolongation of the duration of peripheral nerve block.