Control of respiratory drive by extracorporeal CO2 removal in acute exacerbation of COPD breathing on non-invasive NAVA.

BACKGROUND: Veno-venous extracorporeal CO2 removal (vv-ECCO2R) and non-invasive neurally adjusted ventilator assist (NIV-NAVA) are two promising techniques which may prevent complications related to prolonged invasive mechanical ventilation in patients with acute exacerbation of COPD. METHODS: A physiological study of the electrical activity of the diaphragm (Edi) response was conducted with varying degrees of extracorporeal CO2 removal to control the respiratory drive in patients with severe acute exacerbation of COPD breathing on NIV-NAVA. RESULTS: Twenty COPD patients (SAPS II 37 ± 5.6, age 57 ± 9 years) treated with vv-ECCO2R and supported by NIV-NAVA were studied during stepwise weaning of vv-ECCO2R. Based on dyspnea, tolerance, and blood gases, weaning from vv-ECCO2R was successful in 12 and failed in eight patients. Respiratory drive (measured via the Edi) increased to 19 ± 10 µV vs. 56 ± 20 µV in the successful and unsuccessful weaning groups, respectively, resulting in all patients keeping their CO2 and pH values stable. Edi was the best predictor for vv-ECCO2R weaning failure (ROC analysis AUC 0.95), whereas respiratory rate, rapid shallow breathing index, and tidal volume had lower predictive values. Eventually, 19 patients were discharged home, while one patient died. Mortality at 90 days and 180 days was 15 and 25%, respectively. CONCLUSIONS: This study demonstrates for the first time the usefulness of the Edi signal to monitor and guide patients with severe acute exacerbation of COPD on vv-ECCO2R and NIV-NAVA. The Edi during vv-ECCO2R weaning was found to be the best predictor of tolerance to removing vv-ECCO2R.

Current Trends in Aortic Root Surgery: The Mini-Bentall Approach.

OBJECTIVE: The mini-sternotomy approach is becoming a widespread technique for aortic valve surgery. However, its safety for aortic root replacement has yet to be established. The aim of the present study was to compare the operative outcomes of patients who underwent aortic root replacement via upper mini-sternotomy (mini-Bentall) to patients who underwent Bentall procedure via median sternotomy (full-sternotomy Bentall). METHODS: Between November 1998 and November 2016, 91 consecutive patients underwent full-sternotomy Bentall procedure and 26 patients underwent mini-Bentall procedure. The mini-Bentall procedure was performed via an upper hemisternotomy incision extending to the right fourth intercostal space. Patients with concomitant procedures and those who underwent deep hypothermic circulatory arrest were excluded from the analysis. Outcome variables were operative mortality and major surgical complications, including prolonged length of hospital stay, transfusion rates, reoperation for bleeding, and prolonged ventilatory support. RESULTS: No significant differences were observed on the preoperative, operative, and postoperative characteristics between the two treatment groups. The median cardiopulmonary bypass and aortic cross-clamp times were 169 minutes (interquartile range = 156.0-188.5) and 148 minutes (interquartile range = 131.3-160.3) in the mini-Bentall group, respectively. The median duration of hospitalization in the mini-Bentall group was 6.5 days (interquartile range = 5.0-11.0 days). In-hospital mortality and new renal insufficiency occurred at a frequency of 1.1% and reoperation for bleeding at 6.6% in the group of patients who underwent the conventional Bentall procedure compared with 0% for all these measures in the mini-Bentall group (P > 0.33). There was no significant difference in intraoperative red blood cell transfusion and other major postoperative complications. No strokes were observed in either group, and there were no conversions to median sternotomy in the mini-Bentall group. CONCLUSIONS: An upper hemisternotomy is a feasible technique in patients undergoing elective aortic root replacement surgery. However, future prospective studies are required before these procedures become the standard of care.

Robotic Beating Heart Totally Endoscopic Coronary Artery Bypass in Higher-Risk Patients: Can It be Done Safely?

OBJECTIVE: Patients with a high Society of Thoracic Surgeons (STS) predicted risk of mortality undergoing coronary artery bypass surgery are known to have worse outcomes. Less invasive approaches have been shown to improve morbidity and mortality for these patients. In this study, we examined perioperative outcomes in higher-risk patients undergoing robotic totally endoscopic beating heart coronary artery bypass surgery. METHODS: The STS predicted risk of mortality was reviewed for patients undergoing robotic totally endoscopic beating heart coronary artery bypass surgery at our institution between January 2013 and May 2017. We identified a higher-risk cohort (n = 50) and compared them to a lower-risk cohort (n = 220) during the same period. The higher-risk group was formed from patients with the 50 highest STS scores. Perioperative data were collected retrospectively. RESULTS: There were 50 patients in the higher-risk group (mean STS score = 7.05 ± 4.9, mean age = 73 years) and 220 patients in the lower-risk group (mean STS score = 0.89 ± 0.6, mean age = 64 years). The higher-risk group had significantly greater rates of renal insufficiency, peripheral vascular disease, and lower ejection fraction. The incidence of postoperative re-exploration for bleeding, stroke, myocardial infarction, and prolonged ventilation was similar. Perioperative blood transfusion and hospital length of stay were greater in the higher-risk group. Mortality was lower in the higher-risk group (0% vs 1.8% P = 0.045). Cardiac-related mortality was similar at midterm follow-up. CONCLUSIONS: We conclude that beating heart totally endoscopic beating heart coronary artery bypass surgery can be performed in patients with a higher STS predicted risk of mortality with excellent outcomes. Further studies are warranted to evaluate long-term results of totally endoscopic beating heart coronary artery bypass surgery in this challenging group of patients.

New setting of neurally adjusted ventilatory assist for noninvasive ventilation by facial mask: a physiologic study.

BACKGROUND: Noninvasive ventilation (NIV) is generally delivered using pneumatically-triggered and cycled-off pressure support (PSP) through a mask. Neurally adjusted ventilatory assist (NAVA) is the only ventilatory mode that uses a non-pneumatic signal, i.e., diaphragm electrical activity (EAdi), to trigger and drive ventilator assistance. A specific setting to generate neurally controlled pressure support (PSN) was recently proposed for delivering NIV by helmet. We compared PSN with PSP and NAVA during NIV using a facial mask, with respect to patient comfort, gas exchange, and patient-ventilator interaction and synchrony. METHODS: Three 30-minute trials of NIV were randomly delivered to 14 patients immediately after extubation to prevent post-extubation respiratory failure: (1) PSP, with an inspiratory support ≥8 cmH2O; (2) NAVA, adjusting the NAVA level to achieve a comparable peak EAdi (EAdipeak) as during PSP; and (3) PSN, setting the NAVA level at 15 cmH2O/µV with an upper airway pressure (Paw) limit to obtain the same overall Paw applied during PSP. We assessed patient comfort, peak inspiratory flow (PIF), time to reach PIF (PIFtime), EAdipeak, arterial blood gases, pressure-time product of the first 300 ms (PTP300-index) and 500 ms (PTP500-index) after initiation of patient effort, inspiratory trigger delay (DelayTR-insp), and rate of asynchrony, determined as asynchrony index (AI%). The categorical variables were compared using the McNemar test, and continuous variables by the Friedman test followed by the Wilcoxon test with Bonferroni correction for multiple comparisons (p < 0.017). RESULTS: PSN significantly improved patient comfort, compared to both PSP (p = 0.001) and NAVA (p = 0.002), without differences between the two latter (p = 0.08). PIF (p = 0.109), EAdipeak (p = 0.931) and gas exchange were similar between modes. Compared to PSP and NAVA, PSN reduced PIFtime (p < 0.001), and increased PTP300-index (p = 0.004) and PTP500-index (p = 0.001). NAVA and PSN significantly reduced DelayTR-insp, as opposed to PSP (p < 0.001). During both NAVA and PSN, AI% was <10% in all patients, while AI% was ≥10% in 7 patients (50%) with PSP (p = 0.023 compared with both NAVA and PSN). CONCLUSIONS: Compared to both PSP and NAVA, PSN improved comfort and patient-ventilator interaction during NIV by facial mask. PSN also improved synchrony, as opposed to PSP only. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03041402 . Registered (retrospectively) on 2 February 2017.

Proceedings of the fourth international conference on central hypoventilation.

Central hypoventilation syndromes (CHS) are rare diseases of central autonomic respiratory control associated with autonomous nervous dysfunction. Severe central hypoventilation is the hallmark and the most life-threatening feature. CHS is a group of not-fully defined disorders. Congenital CHS (CCHS) (ORPHA661) is clinically and genetically well-characterized, with the disease-causing gene identified in 2003. CCHS presents at birth in most cases, and associated with Hirschsprung's disease (ORPHA99803) and neural crest tumours in 20% and 5% of cases, respectively. The incidence of CCHS is estimated to be 1 of 200,000 live births in France, yet remains unknown for the rest of the world. In contrast, late-onset CHS includes a group of not yet fully delineated diseases. Overlap with CCHS is likely, as a subset of patients harbours PHOX2B mutations. Another subset of patients present with associated hypothalamic dysfunction. The number of these patients is unknown (less than 60 cases reported worldwide). Treatment of CHS is palliative using advanced techniques of ventilation support during lifetime. Research is ongoing to better understand physiopathological mechanisms and identify potential treatment pathways.The Fourth International Conference on Central Hypoventilation was organised in Warsaw, Poland, April 13-15, 2012, under the patronage of the European Agency for Health and Consumers and Public Health European Agency of European Community. The conference provided a state-of-the-art update of knowledge on all the genetic, molecular, cellular, and clinical aspects of these rare diseases.

Effort-adapted modes of assisted breathing.

PURPOSE OF REVIEW: New developments in mechanical ventilation have focused on increasing the patient's control of the ventilator by implementing information on lung mechanics and respiratory drive. Effort-adapted modes of assisted breathing are presented and their potential advantages are discussed. RECENT FINDINGS: Adaptive support ventilation, proportional assist ventilation with load adjustable gain factors and neurally adjusted ventilatory assist are ventilatory modes that follow the concept of adapting the assist to a defined target, instantaneous changes in respiratory drive or lung mechanics. Improved patient ventilator interaction, sufficient unloading of the respiratory muscles and increased comfort have been recently associated with these ventilator modalities. There are, however, scarce data with regard to outcome improvement, such as length of mechanical ventilation, ICU stay or mortality (commonly accepted targets to demonstrate clinical superiority). SUMMARY: Within recent years, a major step forward in the evolution of assisted (effort-adapted) modes of mechanical ventilation was accomplished. There is growing evidence that supports the physiological concept of closed-loop effort-adapted assisted modes of mechanical ventilation. However, at present, the translation into a clear outcome benefit remains to be proven. In order to fill the knowledge gap that impedes the broader application, larger randomized controlled trials are urgently needed. However, with clearly proven drawbacks of conventional assisted modes such as pressure support ventilation, it is probably about time to leave these modes introduced decades ago behind.