| 11. |
- Mazzinari, Guido, et al.
(author)
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The Association of Intraoperative driving pressure with postoperative pulmonary complications in open versus closed abdominal surgery patients - a posthoc propensity score-weighted cohort analysis of the LAS VEGAS study
- 2021
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In: BMC Anesthesiology. - : BioMed Central (BMC). - 1471-2253 .- 1471-2253. ; 21:1
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Journal article (peer-reviewed)abstract
- BackgroundIt is uncertain whether the association of the intraoperative driving pressure (Delta P) with postoperative pulmonary complications (PPCs) depends on the surgical approach during abdominal surgery. Our primary objective was to determine and compare the association of time-weighted average Delta P (Delta P-TW) with PPCs. We also tested the association of Delta P-TW with intraoperative adverse events.MethodsPosthoc retrospective propensity score-weighted cohort analysis of patients undergoing open or closed abdominal surgery in the 'Local ASsessment of Ventilatory management during General Anaesthesia for Surgery' (LAS VEGAS) study, that included patients in 146 hospitals across 29 countries. The primary endpoint was a composite of PPCs. The secondary endpoint was a composite of intraoperative adverse events.ResultsThe analysis included 1128 and 906 patients undergoing open or closed abdominal surgery, respectively. The PPC rate was 5%. Delta P was lower in open abdominal surgery patients, but Delta P-TW was not different between groups. The association of Delta P-TW with PPCs was significant in both groups and had a higher risk ratio in closed compared to open abdominal surgery patients (1.11 [95%CI 1.10 to 1.20], P < 0.001 versus 1.05 [95%CI 1.05 to 1.05], P < 0.001; risk difference 0.05 [95%CI 0.04 to 0.06], P < 0.001). The association of P-TW with intraoperative adverse events was also significant in both groups but had higher odds ratio in closed compared to open abdominal surgery patients (1.13 [95%CI 1.12- to 1.14], P < 0.001 versus 1.07 [95%CI 1.05 to 1.10], P < 0.001; risk difference 0.05 [95%CI 0.030.07], P < 0.001).ConclusionsP is associated with PPC and intraoperative adverse events in abdominal surgery, both in open and closed abdominal surgery.Trial registrationLAS VEGAS was registered at clinicaltrials.gov (trial identifier NCT01601223).
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| 12. |
- Muders, Thomas, et al.
(author)
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Individualized Positive End-expiratory Pressure and Regional Gas Exchange in Porcine Lung Injury
- 2020
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In: Anesthesiology. - : LIPPINCOTT WILLIAMS & WILKINS. - 0003-3022 .- 1528-1175. ; 132:4, s. 808-824
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Journal article (peer-reviewed)abstract
- Background: In acute respiratory failure elevated intraabdominal pressure aggravates lung collapse, tidal recruitment, and ventilation inhomogeneity. Low positive end-expiratory pressure (PEEP) may promote lung collapse and intrapulmonary shunting, whereas high PEEP may increase dead space by inspiratory overdistension. The authors hypothesized that an electrical impedance tomography-guided PEEP approach minimizing tidal recruitment improves regional ventilation and perfusion matching when compared to a table-based low PEEP/no recruitment and an oxygenation-guided high PEEP/full recruitment strategy in a hybrid model of lung injury and elevated intraabdominal pressure. Methods: In 15 pigs with oleic acid-induced lung injury intraabdominal pressure was increased by intraabdominal saline infusion. PEEP was set in randomized order: (1) guided by a PEEP/inspired oxygen fraction table, without recruitment maneuver; (2) minimizing tidal recruitment guided by electrical impedance tomography after a recruitment maneuver; and (3) maximizing oxygenation after a recruitment maneuver. Single photon emission computed tomography was used to analyze regional ventilation, perfusion, and aeration. Primary outcome measures were differences in PEEP levels and regional ventilation/perfusion matching. Results: Resulting PEEP levels were different (mean +/- SD) with (1) table PEEP: 11 +/- 3 cm H2O; (2) minimal tidal recruitment PEEP: 22 +/- 3 cm H2O; and (3) maximal oxygenation PEEP: 25 +/- 4 cm H2O; P < 0.001. Table PEEP without recruitment maneuver caused highest lung collapse (28 +/- 11% vs. 5 +/- 5% vs. 4 +/- 4%; P < 0.001), shunt perfusion (3.2 +/- 0.8 l/min vs. 1.0 +/- 0.8 l/min vs. 0.7 +/- 0.6 l/min; P < 0.001) and dead space ventilation (2.9 +/- 1.0 l/min vs. 1.5 +/- 0.7 l/min vs. 1.7 +/- 0.8 l/min; P < 0.001). Although resulting in different PEEP levels, minimal tidal recruitment and maximal oxygenation PEEP, both following a recruitment maneuver, had similar effects on regional ventilation/perfusion matching. Conclusions: When compared to table PEEP without a recruitment maneuver, both minimal tidal recruitment PEEP and maximal oxygenation PEEP following a recruitment maneuver decreased shunting and dead space ventilation, and the effects of minimal tidal recruitment PEEP and maximal oxygenation PEEP were comparable.
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| 13. |
- Muders, Thomas, et al.
(author)
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Measurement of Electrical Impedance Tomography-Based Regional Ventilation Delay for Individualized Titration of End-Expiratory Pressure
- 2021
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In: Journal of Clinical Medicine. - : MDPI. - 2077-0383. ; 10:13
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Journal article (peer-reviewed)abstract
- Rationale: Individualized positive end-expiratory pressure (PEEP) titration might be beneficial in preventing tidal recruitment. To detect tidal recruitment by electrical impedance tomography (EIT), the time disparity between the regional ventilation curves (regional ventilation delay inhomogeneity [RVDI]) can be measured during controlled mechanical ventilation when applying a slow inflation of 12 mL/kg of body weight (BW). However, repeated large slow inflations may result in high end-inspiratory pressure (P-EI), which might limit the clinical applicability of this method. We hypothesized that PEEP levels that minimize tidal recruitment can also be derived from EIT-based RVDI through the use of reduced slow inflation volumes.Methods: Decremental PEEP trials were performed in 15 lung-injured pigs. The PEEP level that minimized tidal recruitment was estimated from EIT-based RVDI measurement during slow inflations of 12, 9, 7.5, or 6 mL/kg BW. We compared RVDI and P-EI values resulting from different slow inflation volumes and estimated individualized PEEP levels.Results: RVDI values from slow inflations of 12 and 9 mL/kg BW showed excellent linear correlation (R-2 = 0.87, p < 0.001). Correlations decreased for RVDI values from inflations of 7.5 (R-2 = 0.68, p < 0.001) and 6 (R-2 = 0.42, p < 0.001) mL/kg BW. Individualized PEEP levels estimated from 12 and 9 mL/kg BW were comparable (bias -0.3 cm H2O +/- 1.2 cm H2O). Bias and scatter increased with further reduction in slow inflation volumes (for 7.5 mL/kg BW, bias 0 +/- 3.2 cm H2O; for 6 mL/kg BW, bias 1.2 +/- 4.0 cm H2O). P-EI resulting from 9 mL/kg BW inflations were comparable with P-EI during regular tidal volumes.Conclusions: PEEP titration to minimize tidal recruitment can be individualized according to EIT-based measurement of the time disparity of regional ventilation courses during slow inflations with low inflation volumes(.) This sufficiently decreases P-EI and may reduce potential clinical risks.
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| 14. |
- Neto, Ary Serpa, et al.
(author)
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The LAS VEGAS risk score for prediction of postoperative pulmonary complications : An observational study
- 2018
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In: European Journal of Anaesthesiology. - 0265-0215 .- 1365-2346. ; 35:9, s. 691-701
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Journal article (peer-reviewed)abstract
- BACKGROUND: Currently used pre-operative prediction scores for postoperative pulmonary complications (PPCs) use patient data and expected surgery characteristics exclusively. However, intra-operative events are also associated with the development of PPCs.OBJECTIVE: We aimed to develop a new prediction score for PPCs that uses both pre-operative and intra-operative data.DESIGN: This is a secondary analysis of the LAS VEGAS study, a large international, multicentre, prospective study.SETTINGS: A total of 146 hospitals across 29 countries.PATIENTS: Adult patients requiring intra-operative ventilation during general anaesthesia for surgery.INTERVENTIONS: The cohort was randomly divided into a development subsample to construct a predictive model, and a subsample for validation.MAIN OUTCOME MEASURES: Prediction performance of developed models for PPCs.RESULTS: Of the 6063 patients analysed, 10.9% developed at least one PPC. Regression modelling identified 13 independent risk factors for PPCs: six patient characteristics [higher age, higher American Society of Anesthesiology (ASA) physical score, pre-operative anaemia, pre-operative lower SpO2 and a history of active cancer or obstructive sleep apnoea], two procedure-related features (urgent or emergency surgery and surgery lasting ≥ 1 h), and five intra-operative events [use of an airway other than a supraglottic device, the use of intravenous anaesthetic agents along with volatile agents (balanced anaesthesia), intra-operative desaturation, higher levels of positive end-expiratory pressures > 3 cmH2O and use of vasopressors]. The area under the receiver operating characteristic curve of the LAS VEGAS risk score for prediction of PPCs was 0.78 [95% confidence interval (95% CI), 0.76 to 0.80] for the development subsample and 0.72 (95% CI, 0.69 to 0.76) for the validation subsample.CONCLUSION: The LAS VEGAS risk score including 13 peri-operative characteristics has a moderate discriminative ability for prediction of PPCs. External validation is needed before use in clinical practice.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, number NCT01601223.
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| 15. |
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| 16. |
- Nijbroek, Sunny G., et al.
(author)
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Sex difference and intra-operative tidal volume : Insights from the LAS VEGAS study
- 2021
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In: European Journal of Anaesthesiology. - : Wolters Kluwer. - 0265-0215 .- 1365-2346. ; 38:10, s. 1034-1041
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Journal article (peer-reviewed)abstract
- BACKGROUND One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg−1 or less predicted bodyweight (PBW). A VT was deemed ‘default’ if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg−1 PBW, P < 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P < 0.001]. In the mediation analysis, patients’ height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION The study was registered at Clinicaltrials.gov, NCT01601223
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| 17. |
- Perchiazzi, Gaetano, et al.
(author)
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Acute Respiratory Distress Syndrome (ARDS) : Pathophysiological Insights and Lung Imaging
- 2019
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In: Journal of Clinical Medicine. - : MDPI AG. - 2077-0383. ; 8:12
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Journal article (other academic/artistic)abstract
- Acute respiratory distress syndrome (ARDS) is in the center of the scientific debate both for its complex pathophysiology and for the discussion about the remedies that could contribute to its healing. The intricate interplay of different body systems that characterizes ARDS is mirrored by two main research threads, one centered on the pathophysiological mechanisms of the disease and the other on the new approaches to lung imaging. In this Special Issue of the Journal of Clinical Medicine are presented studies using imaging technologies based on electrical impedance tomography, synchrotron radiation computed tomography and intravital probe-based confocal laser endomicroscopy. The studies on the pathophysiological mechanisms pertain to the evaluation of the biomarkers of the disease and the platelet disfunction during extracorporeal membrane oxygenation. These contributions witness the intensity of ARDS research as many of the key problems of the disease are only in part resolved.
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| 18. |
- Pham, Tai, et al.
(author)
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Outcome of acute hypoxaemic respiratory failure : insights from the LUNG SAFE Study
- 2021
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In: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 57:6
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Journal article (peer-reviewed)abstract
- Background: Current incidence and outcome of patients with acute hypoxaemic respiratory failure requiring mechanical ventilation in the intensive care unit (ICU) are unknown, especially for patients not meeting criteria for acute respiratory distress syndrome (ARDS). Methods: An international, multicentre, prospective cohort study of patients presenting with hypoxaemia early in the course of mechanical ventilation, conducted during four consecutive weeks in the winter of 2014 in 459 ICUs from 50 countries (LUNG SAFE). Patients were enrolled with arterial oxygen tension/inspiratory oxygen fraction ratio <= 300 mmHg, new pulmonary infiltrates and need for mechanical ventilation with a positive end-expiratory pressure of >= 5 cmH(2)O. ICU prevalence, causes of hypoxaemia, hospital survival and factors associated with hospital mortality were measured. Patients with unilateral versus bilateral opacities were compared. Findings: 12 906 critically ill patients received mechanical ventilation and 34.9% with hypoxaemia and new infiltrates were enrolled, separated into ARDS (69.0%), unilateral infiltrate (22.7%) and congestive heart failure (CHF; 8.2%). The global hospital mortality was 38.6%. CHF patients had a mortality comparable to ARDS (44.1% versus 40.4%). Patients with unilateral-infiltrate had lower unadjusted mortality, but similar adjusted mortality compared to those with ARDS. The number of quadrants on chest imaging was associated with an increased risk of death. There was no difference in mortality comparing patients with unilateral-infiltrate and ARDS with only two quadrants involved. Interpretation: More than one-third of patients receiving mechanical ventilation have hypoxaemia and new infiltrates with a hospital mortality of 38.6%. Survival is dependent on the degree of pulmonary involvement whether or not ARDS criteria are reached.
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| 19. |
- Reske, Andreas W., et al.
(author)
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Bedside Estimation of Nonaerated Lung Tissue Using Blood Gas Analysis
- 2013
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In: Critical Care Medicine. - 0090-3493 .- 1530-0293. ; 41:3, s. 732-743
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Journal article (peer-reviewed)abstract
- Objectives: Studies correlating the arterial partial pressure of oxygen to the fraction of nonaerated lung assessed by CT shunt yielded inconsistent results. We systematically analyzed this relationship and scrutinized key methodological factors that may compromise it. We hypothesized that both physiological shunt and the ratio between PaO2 and the fraction of inspired oxygen enable estimation of CT shunt at the bedside. Design: Prospective observational clinical and laboratory animal investigations. Setting: ICUs (University Hospital Leipzig, Germany) and Experimental Pulmonology Laboratory (University of Sao Paulo, Brazil). Patients, Subjects and Interventions: Whole-lung CT and arterial blood gases were acquired simultaneously in 77 patients mechanically ventilated with pure oxygen. A subgroup of 28 patients was submitted to different FIO2. We also studied 19 patients who underwent repeat CT. Furthermore we studied ten pigs with acute lung injury at multiple airway pressures, as well as a theoretical model relating PaO2 and physiological shunt. We logarithmically transformed the PaO2/FIO2 to change this nonlinear relationship into a linear regression problem. Measurements and Main Results: We observed strong linear correlations between Riley's approximation of physiological shunt and CT shunt (R-2 = 0.84) and between logarithmically transformed PaO2/FIO2 and CT shunt (R-2 = 0.86), allowing us to construct a look-up table with prediction intervals. Strong linear correlations were also demonstrated within-patients (R-2 = 0.95). Correlations were significantly improved by the following methodological issues: measurement of PaO2/FIO2 during pure oxygen ventilation, use of logarithmically transformed PaO2/FIO2 instead of the "raw" PaO2/FIO2, quantification of nonaerated lung as percentage of total lung mass and definition of nonaerated lung by the [-200 to +100] Hounsfield Units interval, which includes shunting units within less opacified lung regions. Conclusion: During pure oxygen ventilation, logarithmically transformed PaO2/FIO2 allows estimation of CT shunt and its changes in patients during systemic inflammation. Relevant intrapulmonary shunting seems to occur in lung regions with CT numbers between [-200 and +100] Hounsfield Units.
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| 20. |
- Serpa Neto, Ary, et al.
(author)
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Epidemiological characteristics, practice of ventilation, and clinical outcome in patients at risk of acute respiratory distress syndrome in intensive care units from 16 countries (PRoVENT) : an international, multicentre, prospective study
- 2016
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In: The Lancet Respiratory Medicine. - 2213-2600 .- 2213-2619. ; 4:11, s. 882-893
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Journal article (peer-reviewed)abstract
- Background Scant information exists about the epidemiological characteristics and outcome of patients in the intensive care unit (ICU) at risk of acute respiratory distress syndrome (ARDS) and how ventilation is managed in these individuals. We aimed to establish the epidemiological characteristics of patients at risk of ARDS, describe ventilation management in this population, and assess outcomes compared with people at no risk of ARDS. Methods PRoVENT (PRactice of VENTilation in critically ill patients without ARDS at onset of ventilation) is an international, multicentre, prospective study undertaken at 119 ICUs in 16 countries worldwide. All patients aged 18 years or older who were receiving mechanical ventilation in participating ICUs during a 1-week period between January, 2014, and January, 2015, were enrolled into the study. The Lung Injury Prediction Score (LIPS) was used to stratify risk of ARDS, with a score of 4 or higher defining those at risk of ARDS. The primary outcome was the proportion of patients at risk of ARDS. Secondary outcomes included ventilatory management (including tidal volume [V-T] expressed as mL/kg predicted bodyweight [PBW], and positive end-expiratory pressure [PEEP] expressed as cm H2O), development of pulmonary complications, and clinical outcomes. The PRoVENT study is registered at ClinicalTrials.gov, NCT01868321. The study has been completed. Findings Of 3023 patients screened for the study, 935 individuals fulfilled the inclusion criteria. Of these critically ill patients, 282 were at risk of ARDS (30%, 95% CI 27-33), representing 0.14 cases per ICU bed over a 1-week period. V-T was similar for patients at risk and not at risk of ARDS (median 7.6 mL/kg PBW [IQR 6.7-9.1] vs 7.9 mL/kg PBW [6.8-9.1]; p=0.346). PEEP was higher in patients at risk of ARDS compared with those not at risk (median 6.0 cm H2O [IQR 5.0-8.0] vs 5.0 cm H2O [5.0-7.0]; p<0.0001). The prevalence of ARDS in patients at risk of ARDS was higher than in individuals not at risk of ARDS (19/260 [7%] vs 17/556 [3%]; p=0.004). Compared with individuals not at risk of ARDS, patients at risk of ARDS had higher in-hospital mortality (86/543 [16%] vs 74/232 [32%]; p<0.0001), ICU mortality (62/533 [12%] vs 66/227 [29%]; p<0.0001), and 90-day mortality (109/653 [17%] vs 88/282 [31%]; p<0. 0001). V-T did not differ between patients who did and did not develop ARDS (p=0.471 for those at risk of ARDS; p=0.323 for those not at risk). Interpretation Around a third of patients receiving mechanical ventilation in the ICU were at risk of ARDS. Pulmonary complications occur frequently in patients at risk of ARDS and their clinical outcome is worse compared with those not at risk of ARDS. There is potential for improvement in the management of patients without ARDS. Further refinements are needed for prediction of ARDS.
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