Intraoperative mechanical ventilation practice in thoracic surgery patients and its association with postoperative pulmonary complications: Results of a multicenter prospective observational study

Abstract: Background: Intraoperative mechanical ventilation may influence postoperative pulmonary complications (PPCs). Current practice during thoracic surgery is not well described. Methods: This is a post-hoc analysis of the prospective multicenter cross-sectional LAS VEGAS study focusing on patients who underwent thoracic surgery. Consecutive adult patients receiving invasive ventilation during general anesthesia were included in a one-week period in 2013. Baseline characteristics, intraoperative and postoperative data were registered. PPCs were collected as composite endpoint until the 5th postoperative day. Patients were stratified into groups based on the use of one lung ventilation (OLV) or two lung ventilation (TLV), endoscopic vs. non-endoscopic approach and ARISCAT score risk for PPCs. Differences between subgroups were compared using χ2 or Fisher exact tests or Student’s t-test. Kaplan–Meier estimates of the cumulative probability of development of PPC and hospital discharge were performed. Cox-proportional hazard models without adjustment for covariates were used to assess the effect of the subgroups on outcome. Results: From 10,520 patients enrolled in the LAS VEGAS study, 302 patients underwent thoracic procedures and were analyzed. There were no differences in patient characteristics between OLV vs. TLV, or endoscopic vs. open surgery. Patients received VT of 7.4 ± 1.6 mL/kg, a PEEP of 3.5 ± 2.4 cmH2O, and driving pressure of 14.4 ± 4.6 cmH2O. Compared with TLV, patients receiving OLV had lower VT and higher peak, plateau and driving pressures, higher PEEP and respiratory rate, and received more recruitment maneuvers. There was no difference in the incidence of PPCs in OLV vs. TLV or in endoscopic vs. open procedures. Patients at high risk had a higher incidence of PPCs compared with patients at low risk (48.1% vs. 28.9%; hazard ratio, 1.95; 95% CI 1.05–3.61; p = 0.033). There was no difference in the incidence of severe PPCs. The in-hospital length of stay (LOS) was longer in patients who developed PPCs. Patients undergoing OLV, endoscopic procedures and at low risk for PPC had shorter LOS. Conclusion: PPCs occurred frequently and prolonged hospital LOS following thoracic surgery. Proportionally large tidal volumes and high driving pressure were commonly used in this sub-population. However, large RCTs are needed to confirm these findings. Trial registration: This trial was prospectively registered at the Clinical Trial Register (www.clinicaltrials.gov; NCT01601223; registered May 17, 2012.

The role of non-invasive ventilation in weaning and decannulating critically ill patients with tracheostomy: A narrative review of the literature

Abstract Introduction Invasive mechanical ventilation (IMV) is associated with several complications. Placement of a long-term airway (tracheostomy) is also associated with short and long-term risks for patients. Nevertheless, tracheostomies are placed to help reduce the duration of IMV, facilitate weaning and eventually undergo successful decannulation. Methods We performed a narrative review by searching PubMed, Embase and Medline databases to identify relevant citations using the search terms (with synonyms and closely related words) "non-invasive ventilation", "tracheostomy" and "weaning". We identified 13 publications comprising retrospective or prospective studies in which non-invasive ventilation (NIV) was one of the strategies used during weaning from IMV and/or tracheostomy decannulation. Results In some studies, patients with tracheostomies represented a subgroup of patients on IMV. Most of the studies involved patients with underlying cardiopulmonary comorbidities and conditions, and primarily involved specialized weaning centres. Not all studies provided data on decannulation, although those which did, report high success rates for weaning and decannulation when using NIV as an adjunct to weaning patient off ventilatory support. However, a significant percentage of patients still needed home NIV after discharge. Conclusions The review supports a potential role for NIV in weaning patients with a tracheostomy either off the ventilator and/or with its decannulation. Additional research is needed to develop weaning protocols and better characterize the role of NIV during weaning

Distribution of transpulmonary pressure during one-lung ventilation in pigs at different body positions

Background. Global and regional transpulmonary pressure (PL) during one-lung ventilation (OLV) is poorly characterized. We hypothesized that global and regional PL and driving PL (ΔPL) increase during protective low tidal volume OLV compared to two-lung ventilation (TLV), and vary with body position.Methods. In sixteen anesthetized juvenile pigs, intra-pleural pressure sensors were placed in ventral, dorsal, and caudal zones of the left hemithorax by video-assisted thoracoscopy. A right thoracotomy was performed and lipopolysaccharide administered intravenously to mimic the inflammatory response due to thoracic surgery. Animals were ventilated in a volume-controlled mode with a tidal volume (VT) of 6 mL kg−1 during TLV and of 5 mL kg−1 during OLV and a positive end-expiratory pressure (PEEP) of 5 cmH2O. Global and local transpulmonary pressures were calculated. Lung instability was defined as end-expiratory PL<2.9 cmH2O according to previous investigations. Variables were acquired during TLV (TLVsupine), left lung ventilation in supine (OLVsupine), semilateral (OLVsemilateral), lateral (OLVlateral) and prone (OLVprone) positions randomized according to Latin-square sequence. Effects of position were tested using repeated measures ANOVA.Results. End-expiratory PL and ΔPL were higher during OLVsupine than TLVsupine. During OLV, regional end-inspiratory PL and ΔPL did not differ significantly among body positions. Yet, end-expiratory PL was lower in semilateral (ventral: 4.8 ± 2.9 cmH2O; caudal: 3.1 ± 2.6 cmH2O) and lateral (ventral: 1.9 ± 3.3 cmH2O; caudal: 2.7 ± 1.7 cmH2O) compared to supine (ventral: 4.8 ± 2.9 cmH2O; caudal: 3.1 ± 2.6 cmH2O) and prone position (ventral: 1.7 ± 2.5 cmH2O; caudal: 3.3 ± 1.6 cmH2O), mainly in ventral (p ≤ 0.001) and caudal (p = 0.007) regions. Lung instability was detected more often in semilateral (26 out of 48 measurements; p = 0.012) and lateral (29 out of 48 measurements, p < 0.001) as compared to supine position (15 out of 48 measurements), and more often in lateral as compared to prone position (19 out of 48 measurements, p = 0.027).Conclusion. Compared to TLV, OLV increased lung stress. Body position did not affect stress of the ventilated lung during OLV, but lung stability was lowest in semilateral and lateral decubitus position

non invasive ventilation during surgery under neuraxial anaesthesia a pathophysiological perspective on application and benefits and a systematic literature review

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The European medicines agency and the authorization for hydroxyethyl starch containing solutions\u2013killing the cow to get rid of ticks?

The European Medicines Agency (EMA) has advised taking HES off the market.There are numerous questions arising from this decision:First, and most importantly, do you agree?Then: Since 2013, we have already several limitations of HES (in duration, dose and indications), which have been - albeit still questionable-generally accepted. Currently, HES is indicated for surgical and trauma patients with hypovolaemia caused by acute blood loss when crystalloids alone are not considered sufficient. If the "ban" is accepted, (how) can we replace HES in these patients? Gelatins (Less effective), or albumin (money!!!), or can we assume/hope that there is no case where crystalloids are not sufficient? Indeed, don't we need any colloid anymore?The arguments of EMA are another topic to discuss: a) doctors ignore contraindications, b) it is too difficult to distinguish between patients who might profit or be harmed from HES; c) further measures would be ineffective. Do you agree these arguments? The authority banning from utilizing a drug because of ignoring contraindications, is this not a limiting behavior one considers fit for immature? Furthermore: If you start with "doctors ignore contraindications", can it be possible we can ban any existing drug? (Or where is the breaking point?)HES's scientific history is shameful. Can it be possible, that maybe-just maybe-this fact has affected the recommendation of EMA? (A turkish quote says (liberally translated): "Do not forsake the church, even if you are angry with the priest"). As a matter of fact, we need to be more suspicious about the studies comparing different types of fluids, no matter if the results are "pro" or "con" the use of HES. How do you comment different studies

PEEP in thoracic anesthesia: PROS and CONS

Protective ventilation includes a strategy with low tidal volume, Plateau pressure, driving pressure, positive end-expiratory pressure (PEEP), and recruitment maneuvers on the ventilated lung. The rationale for the application of PEEP during one-lung ventilation (OLV) is that PEEP may contribute to minimize atelectrauma, preventing airway closure and alveolar collapse and improving the ventilation/perfusion to the ventilated lung. However, in case of high partial pressure of oxygen the application of PEEP may cause increased pulmonary vascular resistance, thus diverting blood flow to the non-ventilated lung, and worsening ventilation/perfusion. Further, PEEP may be associated with higher risk of hemodynamic impairment, increased need for fluids and vasoactive drugs. Positive effects on outcome have been reported by titrating PEEP according to driving pressure, targeted to obtain the optimum respiratory as well as pulmonary system compliance. This may vary according to the method employed for titration and should be performed individually for each patient. In summary, the potential for harm combined with the lack of evidence for improved outcome suggest that PEEP must be judiciously used during OLV even when titrated to a safe target, and only as much as necessary to maintain an appropriate gas exchange under low protective tidal volumes and driving pressures

Practice of oxygen use in anesthesiology : a survey of the European Society of Anaesthesiology and Intensive Care

Background Oxygen is one of the most commonly used drugs by anesthesiologists. The World Health Organization (WHO) gave recommendations regarding perioperative oxygen administration, but the practice of oxygen use in anesthesia, critical emergency, and intensive care medicine remains unclear. Methods We conducted an online survey among members of the European Society of Anaesthesiology and Intensive Care (ESAIC). The questionnaire consisted of 46 queries appraising the perioperative period, emergency medicine and in the intensive care, knowledge about current recommendations by the WHO, oxygen toxicity, and devices for supplemental oxygen therapy. Results Seven hundred ninety-eight ESAIC members (2.1% of all ESAIC members) completed the survey. Most respondents were board-certified and worked in hospitals with > 500 beds. The majority affirmed that they do not use specific protocols for oxygen administration. WHO recommendations are unknown to 42% of respondents, known but not followed by 14%, and known and followed by 24% of them. Respondents prefer inspiratory oxygen fraction (FiO(2)) >= 80% during induction and emergence from anesthesia, but intraoperatively = 80 years, or presenting with respiratory distress, chronic obstructive pulmonary disease, myocardial infarction, and stroke. In the intensive care unit, oxygen is mostly targeted at 96%, especially in patients with pulmonary diseases. Conclusions The current practice of perioperative oxygen therapy among respondents does not follow WHO recommendations or current evidence, and access to postoperative monitoring devices impairs the individualization of oxygen therapy. Further research and additional teaching about use of oxygen are necessary

Effects of two stepwise lung recruitment strategies on respiratory function and haemodynamics in anaesthetised pigs: A randomised crossover study

BACKGROUND: Lung recruitment manoeuvres and positive end-expiratory pressure (PEEP) can improve lung function during general anaesthesia. Different recruitment manoeuvre strategies have been described in large international trials: in the protective ventilation using high vs. low PEEP (PROVHILO) strategy, tidal volume (VT) was increased during volume-controlled ventilation; in the individualised peri-operative open-lung approach vs. standard protective ventilation in abdominal surgery (iPROVE) strategy, PEEP was increased during pressure-controlled ventilation. OBJECTIVES: To compare the effects of the PROVHILO strategy and the iPROVE strategy on respiratory and haemodynamic variables. DESIGN: Randomised crossover study. SETTING: University hospital research facility. ANIMALS: A total of 20 juvenile anaesthetised pigs. INTERVENTIONS: Animals were assigned randomly to one of two sequences: PROVHILO strategy followed by iPROVE strategy or vice-versa (n = 10/sequence). In the PROVHILO strategy, VT was increased stepwise by 4 ml kg-1 at a fixed PEEP of 12 cmH2O until a plateau pressure of 30 to 35 cmH2O was reached. In the iPROVE strategy, at fixed driving pressure of 20 cmH2O, PEEP was increased up to 20 cmH2O followed by PEEP titration according to the lowest elastance of the respiratory system (ERS). MAIN OUTCOME MEASURES: We assessed regional transpulmonary pressure (Ptrans), respiratory system mechanics, gas exchange and haemodynamics, as well as the centre of ventilation (CoV) by electrical impedance tomography. RESULTS: During recruitment manoeuvres with the PROVHILO strategy compared with the iPROV strategy, dorsal Ptrans was lower at end-inspiration (16.3 ± 2.7 vs. 18.6 ± 3.1 cmH2O, P = 0.001) and end-expiration (4.8 ± 2.6 vs. 8.8 ± 3.4 cmH2O, P  < 0.001), and mean arterial pressure (MAP) was higher (77 ± 11 vs. 60 ± 14 mmHg, P < 0.001). At 1 and 15 min after recruitment manoeuvres, ERS was higher in the PROVHILO strategy than the iPROVE strategy (24.6 ± 3.9 vs. 21.5 ± 3.4 and 26.7 ± 4.3 vs. 24.0 ± 3.8 cmH2O l-1; P  < 0.001, respectively). At 1 min, PaO2 was lower in PROVHILO compared with iPROVE strategy (57.1 ± 6.1 vs. 59.3 ± 5.1 kPa, P = 0.013), but at 15 min, values did not differ. CoV did not differ between strategies. CONCLUSION: In anaesthetised pigs, the iPROVE strategy compared with the PROVHILO strategy increased dorsal Ptrans at the cost of lower MAP during recruitment manoeuvres, and decreased ERS thereafter, without consistent improvement of oxygenation or shift of the CoV. TRIAL REGISTRATION: This study was registered and approved by the Landesdirektion Dresden, Germany (DD24-5131/338/28)

Changes in lung aeration and respiratory function after open abdominal surgery: A quantitative magnetic resonance imaging study

Background: Atelectasis is one of the most common respiratory complications in patients undergoing open abdominal surgery. Peripheral oxygen saturation (SpO2) and forced vital capacity (FVC) are bedside indicators of postoperative respiratory dysfunction. The aim of this study was to describe the changes in lung aeration, using quantitative analysis of magnetic resonance imaging (MRI) and the diagnostic accuracy of SpO2 and FVC to detect postoperative atelectasis. Methods: Post-hoc analysis of a randomized trial conducted at a University Hospital in Dresden, Germany. Patients undergoing pre- and postoperative lung MRI were included. MRI signal intensity was analyzed quantitatively to define poorly and nonaerated lung compartments. Postoperative atelectasis was defined as nonaerated lung volume above 2% of the total lung volume in the respective MRI investigation. Results: This study included 45 patients, 27 with and 18 patients without postoperative atelectasis. Patients with atelectasis had higher body mass index (p =.024), had more preoperative poorly aerated lung volume (p =.049), a lower preoperative SpO2 (p =.009), and a lower preoperative FVC (p =.029). The amount of atelectasis correlated with preoperative SpO2 (Spearman's ρ = −.51, p <.001) and postoperative SpO2 (ρ = −.60, p <.001), and with preoperative FVC (ρ = −.29, p =.047) and postoperative FVC (ρ = −.40, p =.006). A postoperative SpO2 ≤ 94% had 74% sensitivity and 78% specificity to detect atelectasis, while postoperative FVC ≤ 50% had 56% sensitivity and 100% specificity to detect atelectasis. Conclusion: SpO2 and FVC correlated with the amount of postoperative non-aerated lung volume, showing acceptable diagnostic accuracy in bedside detection of postoperative atelectasis