Start Of Mechanical Ventilation Research Articles

Recombinant thrombomodulin and recombinant antithrombin attenuate pulmonary endothelial glycocalyx degradation and neutrophil extracellular trap formation in ventilator-induced lung injury in the context of endotoxemia

BackgroundVascular endothelial damage is involved in the development and exacerbation of ventilator-induced lung injury (VILI). Pulmonary endothelial glycocalyx and neutrophil extracellular traps (NETs) are endothelial protective and damaging factors, respectively; however, their dynamics in VILI and the effects of recombinant thrombomodulin and antithrombin on these dynamics remain unclear. We hypothesized that glycocalyx degradation and NETs are induced by VILI and suppressed by recombinant thrombomodulin, recombinant antithrombin, or their combination.MethodsVILI was induced in male C57BL/6J mice by intraperitoneal lipopolysaccharide injection (20 mg/kg) and high tidal volume ventilation (20 mL/kg). In the intervention groups, recombinant thrombomodulin, recombinant antithrombin, or their combination was administered at the start of mechanical ventilation. Glycocalyx degradation was quantified by measuring serum syndecan-1, fluorescence-labeled lectin intensity, and glycocalyx-occupied area in the pulmonary vascular lumen. Double-stranded DNA in the bronchoalveolar fluid and fluorescent areas of citrullinated histone H3 and myeloperoxidase were quantified as NET formation.ResultsSerum syndecan-1 increased, and lectin fluorescence intensity decreased in VILI. Electron microscopy revealed decreases in glycocalyx-occupied areas within pulmonary microvessels in VILI. Double-stranded DNA levels in the bronchoalveolar lavage fluid and the fluorescent area of citrullinated histone H3 and myeloperoxidase in lung tissues increased in VILI. Recombinant thrombomodulin, recombinant antithrombin, and their combination reduced glycocalyx injury and NET marker levels. There was little difference in glycocalyx injury and NET makers between the intervention groups.ConclusionVILI induced glycocalyx degradation and NET formation. Recombinant thrombomodulin and recombinant antithrombin attenuated glycocalyx degradation and NETs in our VILI model. The effect of their combination did not differ from that of either drug alone. Recombinant thrombomodulin and antithrombin have the potential to be therapeutic agents for biotrauma in VILI.

Machine learning predicts lung recruitment in acute respiratory distress syndrome using single lung CT scan

BackgroundTo develop and validate classifier models that could be used to identify patients with a high percentage of potentially recruitable lung from readily available clinical data and from single CT scan quantitative analysis at intensive care unit admission. 221 retrospectively enrolled mechanically ventilated, sedated and paralyzed patients with acute respiratory distress syndrome (ARDS) underwent a PEEP trial at 5 and 15 cmH2O of PEEP and two lung CT scans performed at 5 and 45 cmH2O of airway pressure. Lung recruitability was defined at first as percent change in not aerated tissue between 5 and 45 cmH2O (radiologically defined; recruiters: Δ45-5non-aerated tissue > 15%) and secondly as change in PaO2 between 5 and 15 cmH2O (gas exchange-defined; recruiters: Δ15-5PaO2 > 24 mmHg). Four machine learning (ML) algorithms were evaluated as classifiers of radiologically defined and gas exchange-defined lung recruiters using different models including different variables, separately or combined, of lung mechanics, gas exchange and CT data.ResultsML algorithms based on CT scan data at 5 cmH2O classified radiologically defined lung recruiters with similar AUC as ML based on the combination of lung mechanics, gas exchange and CT data. ML algorithm based on CT scan data classified gas exchange-defined lung recruiters with the highest AUC.ConclusionsML based on a single CT data at 5 cmH2O represented an easy-to-apply tool to classify ARDS patients in recruiters and non-recruiters according to both radiologically defined and gas exchange-defined lung recruitment within the first 48 h from the start of mechanical ventilation.

Impact of Serum Vitamin D Status on the Outcome of Ventilator-Associated Pneumonia in Neonates

Objectives: The aim of this work was to study the status of serum vitamin D level on the outcome of ventilator associated pneumonia (VAP) in neonates.
 Methods: This prospective cohort study was carried out on 60 intubated neonates with gestational age > 32 weeks and ventilated for more than 48 h and included two groups, VAP group (n=30) and non-VAP group (n=30). Serum 25-hydroxy Vit D was tested at the start of mechanical ventilation, while blood culture and endotracheal culture were obtained after 2 days of mechanical ventilation and when VAP was suspected.
 Results: The mean serum level of vitamin D in VAP group was statistically significantly lower than non-VAP group. Also, the total duration of mechanical ventilation, duration of O2 supplementation post extubation and duration of hospital stay were statistically significantly longer in VAP group. Although the mortality was higher in neonates developed VAP, it didn’t achieve a statistically significant difference. A cut off value of ≤17.35 ng/ml of serum 25-hydroxy vitamin D showed a sensitivity of 83.33%, specificity of 100% and area under curve (AUC) was 0.895 to predict neonatal VAP.
 Conclusion: 25-hydroxy vitamin D deficiency is an important risk factor for VAP development in neonates, and low vitamin D levels is associated with significant longer duration of mechanical ventilation, post extubation O2 support and hospital stay in neonates with VAP.

Identification of Potential Urinary Metabolite Biomarkers of Pseudomonas aeruginosa Ventilator-Associated Pneumonia.

Introduction:Ventilator-associated pneumonia (VAP) caused by Pseudomonas aeruginosa is a major cause of morbidity and mortality in hospital intensive care units (ICU). Rapid identification of P. aeruginosa-derived markers in easily accessible patients’ samples can enable an early detection of P. aeruginosa VAP (VAP-PA), thereby stewarding antibiotic use and improving clinical outcomes.Methods:Metabolites were analysed using liquid chromatography-mass spectrometry (LC-MS) in prospectively collected urine samples from mechanically ventilated patients admitted to the Antwerp University Hospital ICU. Patients were followed from the start of mechanical ventilation (n = 100 patients) till the time of clinical diagnosis of VAP (n = 13). Patients (n = 8) in whom diagnosis of VAP was further confirmed by culturing respiratory samples and urine samples were studied for semi-quantitative metabolomics.Results:We first show that multivariate analyses highly discriminated VAP-PA from VAP–non-PA as well as from the pre-infection groups (R2 = .97 and .98, respectively). A further univariate analysis identified 58 metabolites that were significantly elevated or uniquely present in VAP-PA compared to the VAP–non-PA and pre-infection groups (P < .05). These comprised both a known metabolite of histidine as well as a novel nicotine metabolite. Most interestingly, we identified 3 metabolites that were not only highly upregulated for, but were also highly specific to, VAP-PA, as these metabolites were completely absent in all pre-infection timepoints and in VAP–non-PA group.Conclusions:Considerable differences exist between urine metabolites in VAP-PA compared to VAP due to other bacterial aetiologies as well to non-VAP (pre-infection) timepoints. The unique urinary metabolic biomarkers we describe here, if further validated, could serve as highly specific diagnostic biomarkers of VAP-PA.

Positive End-Expiratory Pressure Setting in COVID-19-Related Acute Respiratory Distress Syndrome: Comparison Between Electrical Impedance Tomography, PEEP/FiO2 Tables, and Transpulmonary Pressure.

Introduction: The best way to titrate the positive end-expiratory pressure (PEEP) in patients suffering from acute respiratory distress syndrome is still matter of debate. Electrical impedance tomography (EIT) is a non-invasive technique that could guide PEEP setting based on an optimized ventilation homogeneity.Methods: For this study, we enrolled the patients with 2019 coronavirus disease (COVID-19)-related acute respiratory distress syndrome (ARDS), who required mechanical ventilation and were admitted to the ICU in March 2021. Patients were monitored by an esophageal catheter and a 32-electrode EIT device. Within 48 h after the start of mechanical ventilation, different levels of PEEP were applied based upon PEEP/FiO2 tables, positive end-expiratory transpulmonary (PL)/ FiO2 table, and EIT. Respiratory mechanics variables were recorded.Results: Seventeen patients were enrolled. PEEP values derived from EIT (PEEPEIT) were different from those based upon other techniques and has poor in-between agreement. The PEEPEIT was associated with lower plateau pressure, mechanical power, transpulmonary pressures, and with a higher static compliance (Crs) and homogeneity of ventilation.Conclusion: Personalized PEEP setting derived from EIT may help to achieve a more homogenous distribution of ventilation. Whether this approach may translate in outcome improvement remains to be investigated.

Hemodynamic status of patients with different comorbidities of ischemic heart disease before and after coronary artery bypass grafting

Aim. To assess the hemodynamic status by transpulmonary thermodilution (TPTD) in patients with ischemic heart disease (IHD) with different comorbidities before and after coronary artery bypass grafting (CABG).Materials and methods. 66 patients with IHD (40 men and 26 women) aged 53 to 77 years who were admitted for planned CABG were examined. The patients were divided into three groups according to the comorbidity: cardiovascular, respiratory, and metabolic. The first comorbidity was represented by a combination of IHD and multifocal atherosclerosis, the second – by IHD and chronic obstructive pulmonary disease (COPD), and the third – by IHD and metabolic syndrome (MS). All patients underwent CABG with the use of cardiopulmonary bypass. Hemodynamic parameters were recorded by the TPTD method using the Pulsion Picco Plus module (Germany) at 3 stages: after the start of mechanical ventilation (stage I), after the completion of cardiopulmonary bypass (stage II), and 24 hours after CABG (stage III).Results. The patients with IHD with different comorbidities differed in characteristic signs of hemodynamic changes. In IHD with comorbid COPD, after withdrawal from the cardiopulmonary bypass and 24 hours after CABG, the highest index of systemic vascular resistance, the minimum values of the global ejection fraction, and a decrease in the global end-diastolic volume and pulmonary blood volume less noticeable compared with other groups of patients were noted. With comorbid respiratory and metabolic disorders, the maximum values for the indices of extravascular lung water and pulmonary vascular permeability were recorded. In the patients with a comorbid cardiovascular disease, hemodynamic and volume status violations in the dynamic follow-up were less pronounced.Conclusion. The use of the TPTD method in patients with IHD before and after CABG makes it possible to specify the functional state of the circulatory system in different comorbidities, which increases the effectiveness of risk stratification and the accuracy of predicting possible complications.

Invasive mechanical ventilation and clinical parameters in COVID19 patient: Can age be a factor?

BackgroundSeverity of corona virus disease 2019 (COVID19) is presented with respiratory distress and requires mechanical ventilation. Advanced age is one of the significant risk factors of the worst prognosis and mortality in this disease. The aim of this study is to investigate the clinical parameter among COVID19 patients under mechanical ventilation in regard to the age groups. MethodIn this retrospective study, COVID19 patients under invasive mechanical ventilation at Shahid Beheshti Hospital in Qom were included. The patients were divided in two age groups, those aged ≥50 years and <50 years. Clinical parameter of these patients like blood pressure, heart rate, respiratory rate, oxygen saturation and body temperature were recorded at the time of mechanical ventilation and 24, 48 and 72 h under the mechanical ventilation. ResultA total of 317 patients were included in the study where 214 patients were over the age of 50 years and 98 were under 50 years. The mean age of patients was 59.71 ± 16.46 year. At the start of mechanical ventilation and 24, 48 and 72 h during the ventilation, blood pressure, pulse rate, rate of respiration, oxygen saturation, Glasgow coma scale and temperature were not significantly different at among the two age groups, p > 0.05, respectively. ConclusionsThe findings of the study indicated that prognosis of COVID19 patients under invasive mechanical ventilation in terms of changes in clinical parameters might not be associated with the age.

Monitoring Transcutaneously Measured Partial Pressure of CO2 During Intubation in Critically Ill Subjects.

The risk for severe hypoxemia during endotracheal intubation is a major concern in the ICU, but little attention has been paid to CO2 variability. The objective of this study was to assess transcutaneously measured partial pressure of CO2 ([Formula: see text]) throughout intubation in subjects in the ICU who received standard oxygen therapy, high-flow nasal cannula oxygen therapy, or noninvasive ventilation for preoxygenation. We hypothesized that the 3 methods differ in terms of ventilation and CO2 removal. In this single-center, prospective, observational study, we recorded [Formula: see text] from preoxygenation to 3 h after the initiation of mechanical ventilation among subjects requiring endotracheal intubation. Subjects were sorted into 3 groups according to the preoxygenation method. We then assessed the link between [Formula: see text] variability and the development of postintubation hypotension. A total of 202 subjects were included in the study. The [Formula: see text] values recorded at endotracheal intubation, at the initiation of mechanical ventilation, and after 30 min and 1 h of mechanical ventilation were significantly higher than those recorded during preoxygenation (P < .05). [Formula: see text] variability differed significantly according to the preoxygenation method (P < .001, linear mixed model). A decrease in [Formula: see text] by > 5 mm Hg within 30 min after the start of mechanical ventilation was independently associated with postintubation hypotension (odds ratio = 2.14 [95% CI 1.03-4.44], P = .039) after adjustments for age, Simplified Acute Physiology Score II, COPD, cardiac comorbidity, the use of propofol for anesthetic induction, and minute ventilation at the start of mechanical ventilation. [Formula: see text] variability during intubation is significant and differs with the method of preoxygenation. A decrease in [Formula: see text] after the beginning of mechanical ventilation was associated with postintubation hypotension. (ClinicalTrials.gov registration NCT0388430.).

Development of a prognostic scoring system in patients with pneumonia requiring ventilator care for more than 4 days: a single-center observational study.

BackgroundThe aim of the present study was to develop a prognostic model using demographic characteristics, comorbidities, and clinical variables measured on day 4 of mechanical ventilation (MV) for patients with prolonged acute mechanical ventilation (PAMV; MV for >96 hours). MethodsData from 437 patients (70.9% male; median age, 68 years) were obtained over a period of 9 years. All patients were diagnosed with pneumonia. Binary logistic regression identified factors predicting mortality at 90 days after the start of MV. A PAMV prognosis score was calculating ß-coefficient values and assigning points to variables.ResultsThe overall 90-day mortality rate was 47.1%. Five factors (age ≥65 years, body mass index <18.5 kg/m2, hemato-oncologic diseases as comorbidities, requirement for vasopressors on day 4 of MV and requirement for neuromuscular blocking agents on day 4 of MV) were identified as prognostic indicators. Each factor was valued as +1 point, and used to develop a PAMV prognosis score. This score showed acceptable discrimination (area under the receiver operating characteristic curve of 0.695 for mortality, 95% confidence interval 0.650–0.738, p<0.001), and calibration (Hosmer–Lemeshow chi-square=6.331, with df 7 and p=0.502). The cutoff value for predicting mortality based on the maximum Youden index was ≤2 (sensitivity, 87.5%; specificity, 41.3%). For patients with PAMV scores ≤1, 2, 3 and ≥4, the 90-day mortality rates were 29.2%, 45.7%, 67.9%, and 90.9%, respectively (P<0.001).ConclusionsOur study developed a PAMV prognosis score for predicting 90-day mortality. Further research is needed to validate the utility of this score.

Lung aeration and ventilation after general anesthesia in left lateral position: a prospective observational study using electrical impedance tomography

Endoscopic submucosal dissection (ESD) under general anesthesia in left lateral position may lead to transient impairment of pulmonary function. We used electrical impedance tomography (EIT), an increasingly implied non-invasive instrument for bedside real-time monitoring regional changes in ventilation, to assess the changes of regional lung aeration and ventilation in patients undergoing ESD. Twenty-two patients scheduled for elective ESD under mechanical ventilation in left lateral position were studied. We acquired 2-min EIT records at four time points: (M1) baseline, before induction of anesthesia, (M2) after the start of mechanical ventilation and before surgery, (M3) after surgery and before extubation, and (M4) after extubation and before leaving operation room, respectively. To quantify regional changes in lung ventilation, we calculated the ventilation proportion of left and right lung regions. Possible changes in lung aeration were detected by changes in end-expiratory lung impedance (EELI). Global inhomogeneity index (GI) was also analyzed. After tracheal intubation in the left lateral position, left lung showed a lower ventilation proportion (M1, 49.6% vs. M2, 36.2% P<0.05), a reduction in EELI {∆EELI -87 [-809; 253]} and a higher GI index value (M1, 0.29±0.09 vs. M2, 0.41±0.12, P<0.05), while right lung showed a higher ventilation proportion (M1, 50.4% vs. M2, 63.8%, P<0.05) and an increase in EELI {∆EELI 161 [-952; 1,905]}. During ESD operation, no changes in either regional ventilation distribution or GI index were observed. After extubation, the GI values in right and left lung were both returned to the level before anesthesia. In patients with left lateral position undergoing ESD, left lung was characterized by decreased ventilation and more inhomogeneity while right lung was opposite after intubation. ESD procedure with carbon dioxide insufflation did not lead to significant changes in either regional ventilation or homogeneity. And the change of lung inhomogeneity during ESD procedure is transient.

μImpact of a nursing-driven sedation protocol with criteria for infusion initiation in the surgical intensive care unit

PurposeAnalgesia and sedation protocols (ASPs) reduce duration of mechanical ventilation (MV) in the medical intensive care unit (ICU), but data in the surgical ICU (SICU) are limited. The objective of this study was to determine the impact of a nursing-driven ASP with criteria for infusion initiation in the SICU. Materials and MethodsA single-center, retrospective study compared ventilator-free days at day 28 from start of MV (VFD28) before and after ASP implementation. Secondary endpoints included cumulative opioid and sedative requirements, level of sedation, incidence of delirium, SICU and hospital length of stay. ResultsOne hundred thirty two patients were included (66 per group). The protocol group had greater VFD28 compared to the control group (21 vs. 14.5 days, p = .04). Lower rates of benzodiazepine (42.4% vs. 84.8%, p < .001) and opioid (24.2 vs. 78.8, p < .001) infusion use occurred in the protocol group, resulting in lower cumulative doses per ventilator-day through day 7. The protocol group had more documented sedation scores within target range. There were no differences in ICU delirium, SICU or hospital length of stay. ConclusionsA nursing-driven ASP with criteria for infusion initiation in mechanically-ventilated SICU patients may increase ventilator-free time, maintain patients at the target sedation goal, and reduce opioid and benzodiazepine utilization.

Angiotensin II type 2 receptor agonist Compound 21 attenuates pulmonary inflammation in a model of acute lung injury.

PurposeAlthough the role of the angiotensin II type 2 (AT2) receptor in acute lung injury is not yet completely understood, a protective role of this receptor subtype has been suggested. We hypothesized that, in a rodent model of acute lung injury, stimulation of the AT2 receptor with the direct agonist Compound 21 (C21) might have a beneficial effect on pulmonary inflammation and might improve pulmonary gas exchange.Materials and methodsMale adult rats were divided into a treatment group that received pulmonary lavage followed by mechanical ventilation (LAV, n=9), a group receiving pulmonary lavage, mechanical ventilation, and direct stimulation of the AT2 receptor with C21 (LAV+C21, n=9), and a control group that received mechanical ventilation only (control, n=9). Arterial blood gas analysis was performed every 30 min throughout the 240-min observation period. Lung tissue and plasma samples were obtained at 240 min after the start of mechanical ventilation. Protein content and surface activity of bronchoalveolar lavage fluid were assessed and the wet/dry-weight ratio of lungs was determined. Transcriptional and translational regulation of pro- and antiinflammatory cytokines IL-1β, tumor necrosis factor-alpha, IL-6, IL-10, and IL-4 was determined in lungs and in plasma.ResultsPulmonary lavage led to a significant impairment of gas exchange, the formation of lung edema, and the induction of pulmonary inflammation. Protein content of lavage fluid was increased and contained washed-out surfactant. Direct AT2 receptor stimulation with C21 led to a significant inhibition of tumor necrosis factor-alpha and IL-6 expressions in the lungs, whereas the expressions of IL-1, IL-10, and IL-4 remained unchanged. During the 240-min observation period, AT2 receptor stimulation did not improve pulmonary gas exchange or lung edema.ConclusionIn this rodent model of acute lung injury after repeated pulmonary lavage, AT2 receptor stimulation attenuates pulmonary inflammation but does not improve gas exchange.

The impact of early percutaneous tracheotomy on reduction of the incidence of ventilator associated pneumonia and the course and outcome of ICU patients

The aim of the study. The primary objec-tive of this study was to determine the differences in the incidence of respiratory infections and septic episodes in patients who underwent early percutaneous trache-otomy (ET) and in patients who underwent translaryngeal intubation i.e late trache-otomy (LT). Secondary objectives were to determine the differences in the early mortality of patients, duration of mechani-cal ventilation and length of&nbsp;Intensive care unit (ICU) stay.Materials and methods. The study included 72 surgical and trauma patients older than 18 years of age, treated at the ICU of the University Clinical Hospital Mostar who had undergone translaryngeal intubation and were mechanically ventilated for at least 48 hours. The basic criterion for inclu-sion in the study was expected duration of mechanical ventilation of at least 14 days. Forty-eight hours after enrollment, patients were randomly divided into two groups. The first group of patients underwent ET after 2-4 days of mechanical ventilation; the second group underwent LT if they ex-hibited longer episodes of hypoxemia after 15 days.&nbsp;Results. The ET group of patients spent less time in mechanical ventilation and ICU. The ET group had a lower rate of VAS pneumonia (p=0.137), sepsis episodes (p=0.029) and mortality rate (p=0.056). Conclusion. The results of our study sup-port ET being performed 2–4 days from the start of mechanical ventilation. De-spite a lack of power, we found significant&nbsp;benefits of ET regarding the incidence of pneumonia, sepsis, hospital mortality, du-ration of mechanical ventilation and length of ICU stay

Comparison of pulmonary mechanics during isoflurane, sevoflurane, and desflurane anesthesia

Background: Practicing anesthesia clinicians are aware that tracheal intubation increases resistance and alters pulmonary mechanics; thus, comparison of bronchodilating effects of volatile agents is desirable. This study was aimed to compare the respiratory mechanics during isoflurane, sevoflurane, and desflurane anesthesia at 1 minimum alveolar concentration (MAC) and 2 MAC. Materials and Methods: Seventy patients undergoing moderate duration surgery were sequentially allocated into one of the three groups: Group I (Isoflurane; n = 23), Group S (Sevoflurane; n = 24), and Group D (Desflurane; n = 23). Peak inspiratory pressure (PIP), dynamic lung compliance (Cdyn), and airway resistance (Raw) values at three different time points were noted: 3 breaths after the start of mechanical ventilation (T1), 5 min after 1 MAC (T2), and 2 min after 2 MAC (T3). Results: PIP increased significantly in the desflurane group by 6% at 1 MAC and 8.06% at 2 MAC from the baseline. Statistically significant increase in Cdyn by 1.59% at 1 MAC and 9.9% at 2 MAC was found in sevoflurane group. Raw decreased significantly by 24.28% at 1 MAC and by 45.65% at 2 MAC from the baseline in sevoflurane group. Conclusions: We conclude that increasing concentrations from 1 MAC to 2 MAC show more consistent bronchodilating effect of Sevoflurane compared to isoflurane and desflurane. Sevoflurane increased Cdyn and reduced Raw from 1 MAC to 2 MAC.

Fluid balance and clinical outcomes in mechanically ventilated children in pediatric intensive care unit : A retrospective observational, analytical study

Background : Positive fluid balance is shown to have adverse outcomes in mechanically ventilated children with Acute Respiratory Distress Syndrome (ARDS). Our study attempts to provide an understanding of the threshold of fluid balance requiring intervention in the management of mechanically ventilated children. Methods : This retrospective study was conducted in the Division of Pediatric Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER). Medical records from January 2015 to December 2016 were screened. All medical records of children aged 1-month to 13 years admitted to PICU and mechanically ventilated for more than 24 hours with documented input-output balance for at least 48 hours from the start of mechanical ventilation were included. Patients divided into =10% Fluid overload (FO) group and > 10% FO group. Results : Study included 107 children with 84 in =10% FO group and 23 in >10% FO group. The baseline characteristics were similar in terms of age (median 11 months Vs 12 months), sex (M:F = 47:37 Vs 10:13), Pediatric Risk of Mortality (PRISM)- III score (15 Vs 16), inotrope score (20 in both) & vasoactive score (30 in both) and number of patients receiving furosemide [59 (70%) vs 16 (69 %)]. Disordered control of breathing was the most common indication for mechanical ventilation in both groups [37(44%) Vs 12(52%)]. The proportion of children having ARDS [28(35%) Vs 13(56%), p=0.06] and AKI [37(44%) Vs 15(65%), p=0.07] were higher in >10% FO group of which significant number required renal replacement therapy [15(17%) Vs 10(43%), p=0.01]. More children were found to have shock in >10% FO group [58(69%) vs 18(78%), p=0.38] and the proportion of septic shock was significantly higher [27(32%) vs 13(56%), p=0.03]. The >10% FO group had a higher mortality compared to =10% FO group [32(38%) vs 13(57%) RR=1.2, 95%CI 1.0-1.5, p=0.11]. The median (IQR) duration of invasive mechanical ventilation was 6 (4-11) days in =10% FO group and 5 (3-10) days in >10 % FO group (p=0.90). PICU stay was longer in =10% FO group [9 days (6-15) Vs 8 days (6-15) p=0.82]. Ventilator-free days were comparable (23.5 Vs 22.5) and organ dysfunction scores - Pediatric Logistic Organ Dysfunction (PELOD) [12 in both] & Sequential Organ Failure Assessment (SOFA) [8 in both] were similar. The >10% FO group had greater failed extubations (7% Vs 20%) (p=0.23) and higher respiratory morbidity (median Oxygen Saturation Indices 3.55 vs 5.4, p=0.14, Oxygenation Indices calculated for 49 and 12 children respectively were 3.5 Vs 5.15, p=0.59). Conclusion : There was no significant difference in mortality or respiratory morbidity in positive fluid overload >10 % compared to fluid overload =10%. Future prospective studies including a larger number of children are required to obtain more evidence regarding the association of fluid overload with adverse outcomes.

Severe hypercapnia and outcome of mechanically ventilated patients with moderate or severe acute respiratory distress syndrome.

To analyze the relationship between hypercapnia developing within the first 48h after the start of mechanical ventilation and outcome in patients with acute respiratory distress syndrome (ARDS). We performed a secondary analysis of three prospective non-interventional cohort studies focusing on ARDS patients from 927 intensive care units (ICUs) in 40 countries. These patients received mechanical ventilation for more than 12h during 1-month periods in 1998, 2004, and 2010. We used multivariable logistic regression and a propensity score analysis to examine the association between hypercapnia and ICU mortality. We included 1899 patients with ARDS in this study. The relationship between maximum PaCO2 in the first 48h and mortality suggests higher mortality at or above PaCO2 of ≥50mmHg. Patients with severe hypercapnia (PaCO2 ≥50mmHg) had higher complication rates, more organ failures, and worse outcomes. After adjusting for age, SAPS II score, respiratory rate, positive end-expiratory pressure, PaO2/FiO2 ratio, driving pressure, pressure/volume limitation strategy (PLS), corrected minute ventilation, and presence of acidosis, severe hypercapnia was associated with increased risk of ICU mortality [odds ratio (OR) 1.93, 95% confidence interval (CI) 1.32 to 2.81; p=0.001]. In patients with severe hypercapnia matched for all other variables, ventilation with PLS was associated with higher ICU mortality (OR 1.58, CI 95% 1.04-2.41; p=0.032). Severe hypercapnia appears to be independently associated with higher ICU mortality in patients with ARDS. Clinicaltrials.gov identifier, NCT01093482.

Diaphragm Dysfunction in Mechanically Ventilated Patients

Muscle involvement is found in most critical patients admitted to the intensive care unit (ICU). Diaphragmatic muscle alteration, initially included in this category, has been differentiated in recent years, and a specific type of muscular dysfunction has been shown to occur in patients undergoing mechanical ventilation. We found this muscle dysfunction to appear in this subgroup of patients shortly after the start of mechanical ventilation, observing it to be mainly associated with certain control modes, and also with sepsis and/or multi-organ failure. Although the specific etiology of process is unknown, the muscle presents oxidative stress and mitochondrial changes. These cause changes in protein turnover, resulting in atrophy and impaired contractility, and leading to impaired functionality. The term ‘ventilator-induced diaphragm dysfunction’ was first coined by Vassilakopoulos et al. in 2004, and this phenomenon, along with injury cause by over-distention of the lung and barotrauma, represents a challenge in the daily life of ventilated patients.Diaphragmatic dysfunction affects prognosis by delaying extubation, prolonging hospital stay, and impairing the quality of life of these patients in the years following hospital discharge. Ultrasound, a non-invasive technique that is readily available in most ICUs, could be used to diagnose this condition promptly, thus preventing delays in starting rehabilitation and positively influencing prognosis in these patients.

Disfunción diafragmática: una realidad en el paciente ventilado mecánicamente

Muscle involvement is found in most critical patients admitted to the intensive care unit (ICU). Diaphragmatic muscle alteration, initially included in this category, has been differentiated in recent years, and a specific type of muscular dysfunction has been shown to occur in patients undergoing mechanical ventilation. We found this muscle dysfunction to appear in this subgroup of patients shortly after the start of mechanical ventilation, observing it to be mainly associated with certain control modes, and also with sepsis and/or multi-organ failure. Although the specific etiology of process is unknown, the muscle presents oxidative stress and mitochondrial changes. These cause changes in protein turnover, resulting in atrophy and impaired contractility, and leading to impaired functionality. The term ‘ventilator-induced diaphragm dysfunction’ was first coined by Vassilakopoulos et al. in 2004, and this phenomenon, along with injury cause by over-distention of the lung and barotrauma, represents a challenge in the daily life of ventilated patients.Diaphragmatic dysfunction affects prognosis by delaying extubation, prolonging hospital stay, and impairing the quality of life of these patients in the years following hospital discharge. Ultrasound, a non-invasive technique that is readily available in most ICUs, could be used to diagnose this condition promptly, thus preventing delays in starting rehabilitation and positively influencing prognosis in these patients.

Perioperative assessment of regional ventilation during changing body positions and ventilation conditions by electrical impedance tomography

BackgroundLung-protective ventilation is claimed to be beneficial not only in critically ill patients, but also in pulmonary healthy patients undergoing general anaesthesia. We report the use of electrical impedance tomography for assessing regional changes in ventilation, during both spontaneous breathing and mechanical ventilation, in patients undergoing robot-assisted radical prostatectomy. MethodsWe performed electrical impedance tomography measurements in 39 patients before induction of anaesthesia in the sitting (M1) and supine position (M2), after the start of mechanical ventilation (M3), during capnoperitoneum and Trendelenburg positioning (M4), and finally, in the supine position after release of capnoperitoneum (M5). To quantify regional changes in lung ventilation, we calculated the centre of ventilation and ‘silent spaces’ in the ventral and dorsal lung regions that did not show major impedance changes. ResultsCompared with the awake supine position [2.3% (2.3)], anaesthesia and mechanical ventilation induced a significant increase in silent spaces in the dorsal dependent lung [9.2% (6.3); P <0.05]. Capnoperitoneum and the Trendelenburg position led to a significant increase in such spaces [11.5% (8.9)]. Silent space in the ventral lung remained constant throughout anaesthesia. ConclusionElectrical impedance tomography was able to identify and quantify on a breath-by-breath basis circumscribed areas, so-called silent spaces, within healthy lungs that received little or no ventilation during general anaesthesia, capnoperitoneum, and different body positions. As these silent spaces are suggestive of atelectasis on the one hand and overdistension on the other, they might become useful to guide individualized protective ventilation strategies to mitigate the side-effects of anaesthesia and surgery on the lungs.

Changes in uncuffed endotracheal tube leak during laparoscopic inguinal herniorrhaphy in children.

The present study was conducted to investigate changes in uncuffed endotracheal tube (ETT) leak during laparoscopic surgery. The study included 31 patients aged between 1 and 6years scheduled for elective laparoscopic inguinal herniorrhaphy. Inspiratory and expiratory tidal volumes (TVi and TVe) were measured during mechanical ventilation, and ETT leak was calculated using the formula-ETT leak=(TVi-TVe)/TVi×100(%), assessed at the following time-points-5min after the start of mechanical ventilation (T1, baseline), just before the start of surgery (T2), 5min after the induction of pneumoperitoneum with 15° Trendelenburg tilt (T3), and at the end of surgery (T4). Additionally, leak pressure was assessed after successful tracheal intubation (T0, baseline) at T2, T3 and T4. Uncuffed ETT leak significantly decreased at T3 compared with T1 (baseline). Leak pressure significantly increased at T3 and T4 compared with T0 (baseline). Further studies are needed in order to determine whether the results are universal and associated with clinically significant outcomes.