Estimated dead space fraction and the ventilatory ratio are associated with mortality in early ARDS.
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SUBMITTER: Morales-Quinteros L
PROVIDER: S-EPMC6872683 | biostudies-literature | 2019 Nov
REPOSITORIES: biostudies-literature
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Estimated dead space fraction and the ventilatory ratio are associated with mortality in early ARDS.
Morales-Quinteros Luis L Schultz Marcus J MJ Bringué Josep J Calfee Carolyn S CS Camprubí Marta M Cremer Olaf L OL Horn Janneke J van der Poll Tom T Sinha Pratik P Artigas Antonio A Bos Lieuwe D LD
Annals of intensive care 20191121 1
<h4>Background</h4>Indirect indices for measuring impaired ventilation, such as the estimated dead space fraction and the ventilatory ratio, have been shown to be independently associated with an increased risk of mortality. This study aimed to compare various methods for dead space estimation and the ventilatory ratio in patients with acute respiratory distress syndrome (ARDS) and to determine their independent values for predicting death at day 30. The present study is a post hoc analysis of a ...[more]
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Project description:Primary hypothesisWe hypothesized that higher alveolar dead space fraction (AVDSf) at pediatric acute respiratory distress syndrome (PARDS) onset would be associated with right ventricular (RV) systolic dysfunction within the first 24 h of PARDS.Study design and methodsWe performed a retrospective single-center cohort study of PARDS patients with clinically obtained echocardiograms within 24 h. Primary exposure was AVDSf at PARDS onset. Primary outcome was RV systolic dysfunction as defined by RV global longitudinal strain (GLS) (>-18%). Secondary outcomes included pulmonary hypertension (PH) and RV systolic dysfunction as defined by other echocardiogram parameters, and measures of oxygenation. Unadjusted and adjusted logistic and linear regression were used to investigate AVDSf associations with outcomes.ResultsNinety-one patients were included: median age 6.2 years, 46% female, and 65% with moderate or severe PARDS. Median AVDSf was 0.2 (interquartile range [IQR] 0.0-0.3), 33% had RV dysfunction, and 21% had PH. Unadjusted and adjusted logistic regression showed no association between AVDSf and RV systolic dysfunction or PH by any echocardiographic measure, but unadjusted and adjusted linear regression did show an association between AVDSf and PaO2 /FiO2 .ConclusionAVDSf at PARDS onset was not associated with RV systolic dysfunction or PH within 24 h but was associated with PaO2 /FiO2 ratio and may be more reflective of pulmonary causes of ventilation-perfusion mismatch. Future investigations should focus on clarifying the clinical utility of AVDSf in relation to existing metrics throughout the course of PARDS.
| S-EPMC9870940 | biostudies-literature
Project description:BackgroundEstimates for dead space ventilation have been shown to be independently associated with an increased risk of mortality in the acute respiratory distress syndrome and small case series of COVID-19-related ARDS.MethodsSecondary analysis from the PRoVENT-COVID study. The PRoVENT-COVID is a national, multicenter, retrospective observational study done at 22 intensive care units in the Netherlands. Consecutive patients aged at least 18 years were eligible for participation if they had received invasive ventilation for COVID-19 at a participating ICU during the first month of the national outbreak in the Netherlands. The aim was to quantify the dynamics and determine the prognostic value of surrogate markers of wasted ventilation in patients with COVID-19-related ARDS.ResultsA total of 927 consecutive patients admitted with COVID-19-related ARDS were included in this study. Estimations of wasted ventilation such as the estimated dead space fraction (by Harris-Benedict and direct method) and ventilatory ratio were significantly higher in non-survivors than survivors at baseline and during the following days of mechanical ventilation (p < 0.001). The end-tidal-to-arterial PCO2 ratio was lower in non-survivors than in survivors (p < 0.001). As ARDS severity increased, mortality increased with successive tertiles of dead space fraction by Harris-Benedict and by direct estimation, and with an increase in the VR. The same trend was observed with decreased levels in the tertiles for the end-tidal-to-arterial PCO2 ratio. After adjustment for a base risk model that included chronic comorbidities and ventilation- and oxygenation-parameters, none of the dead space estimates measured at the start of ventilation or the following days were significantly associated with 28-day mortality.ConclusionsThere is significant impairment of ventilation in the early course of COVID-19-related ARDS but quantification of this impairment does not add prognostic information when added to a baseline risk model.Trial registrationISRCTN04346342. Registered 15 April 2020. Retrospectively registered.
| S-EPMC8127435 | biostudies-literature
Project description:We tested the association between pulmonary dead-space fraction (ratio of dead space to tidal volume [V(D)/V(T)]) and mortality in subjects with ARDS (Berlin definition, P(aO2)/F(IO2) ? 300 mm Hg; PEEP ? 5 cm H2O) enrolled into a clinical trial incorporating lung-protective ventilation.We conducted a prospective, multi-center study at medical-surgical ICUs in the United States. A total of 126 ALI subjects with acute lung injury were enrolled into a phase 3 randomized, placebo-controlled study of aerosolized albuterol. V(D)/V(T) and pulmonary mechanics were measured within 4 h of enrollment and repeated daily on study days 1 and 2 in subjects requiring arterial blood gases for clinical management.At baseline, non-survivors had a trend toward higher V(D)/V(T) compared with survivors (0.62 ± 0.11 vs 0.56 ± 0.11, respectively, P = .08). Differences in V(D)/V(T) between non-survivors and survivors became significant on study days 1 (0.64 ± 0.12 vs 0.55 ± 0.11, respectively, P = .01) and 2 (0.67 ± 0.12 vs 0.56 ± 0.11, respectively, P = .004). Likewise, the association between VD/VT and mortality was significant on study day 1 (odds ratio per 0.10 change in V(D)/V(T) [95% CI]: 6.84 [1.62-28.84] P = .01; and study day 2: 4.90 [1.28-18.73] P = .02) after adjusting for V(D)/V(T), P(aO2)/F(IO2), oxygenation index, vasopressor use, and the primary risk for ARDS. Using a Cox proportional hazard model, V(D)/V(T) was associated with a trend toward higher mortality (HR = 4.37 [CI 0.99-19.32], P = .052) that became significant when the analysis was adjusted for daily oxygenation index (HR = 1.74 [95% CI 1.12-3.35] P = .04).Markedly elevated V(D)/V(T) (? 0.60) in early ARDS is associated with higher mortality. Measuring V(D)/V(T) may be useful in identifying ARDS patients at increased risk of death who are enrolled into a therapeutic trial.
| S-EPMC4077995 | biostudies-literature
Project description:OBJECTIVES:Physiologic dead space is associated with mortality in acute respiratory distress syndrome, but its measurement is cumbersome. Alveolar dead space fraction relies on the difference between arterial and end-tidal carbon dioxide (alveolar dead space fraction = (PaCO2 - PetCO2) / PaCO2). We aimed to assess the relationship between alveolar dead space fraction and mortality in a cohort of children meeting criteria for acute respiratory distress syndrome (both the Berlin 2012 and the American-European Consensus Conference 1994 acute lung injury) and pediatric acute respiratory distress syndrome (as defined by the Pediatric Acute Lung Injury Consensus Conference in 2015). DESIGN:Secondary analysis of a prospective, observational cohort. SETTING:Tertiary care, university affiliated PICU. PATIENTS:Invasively ventilated children with pediatric acute respiratory distress syndrome. INTERVENTIONS:None. MEASUREMENTS AND MAIN RESULTS:Of the 283 children with pediatric acute respiratory distress syndrome, 266 had available PetCO2. Alveolar dead space fraction was lower in survivors (median 0.13; interquartile range, 0.06-0.23) than nonsurvivors (0.31; 0.19-0.42; p < 0.001) at pediatric acute respiratory distress syndrome onset, but not 24 hours after (survivors 0.12 [0.06-0.18], nonsurvivors 0.14 [0.06-0.25], p = 0.430). Alveolar dead space fraction at pediatric acute respiratory distress syndrome onset discriminated mortality with an area under receiver operating characteristic curve of 0.76 (95% CI, 0.66-0.85; p < 0.001), better than either initial oxygenation index or PaO2/FIO2. In multivariate analysis, alveolar dead space fraction at pediatric acute respiratory distress syndrome onset was independently associated with mortality, after adjustment for severity of illness, immunocompromised status, and organ failures. CONCLUSIONS:Alveolar dead space fraction at pediatric acute respiratory distress syndrome onset discriminates mortality and is independently associated with nonsurvival. Alveolar dead space fraction represents a single, useful, readily obtained clinical biomarker reflective of pulmonary and nonpulmonary variables associated with mortality.
| S-EPMC4740261 | biostudies-literature
Project description:BackgroundThe ventilatory ratio (VR, [minute ventilation × PaCO2]/[predicted body weight × 100 × 37.5]) is associated with mortality in ARDS. The aims of this study were to test whether baseline disease severity or neuromuscular blockade (NMB) modified the relationship between VR and mortality.MethodsThis was a post hoc analysis of the PETAL-ROSE trial, which randomized moderate-to-severe ARDS patients to NMB or control. Survival among patients with different VR trajectories or VR cutoff above and below the median was assessed by Kaplan-Meier analysis. The relationships between single-day or 48-h VR trajectories with 28- or 90-day mortality were tested by logistic regression. Randomization allocation to NMB and markers of disease severity were tested as confounders by multivariable regression and interaction term analyses.ResultsPatients with worsening VR trajectories had significantly lower survival compared to those with improving VR (n = 602, p < 0.05). Patients with VR > 2 (median) at day 1 had a significantly lower 90-day survival compared to patients with VR ≤ 2 (HR 1.36, 95% CI 1.10-1.69). VR at day 1 was significantly associated with 28-day mortality (OR = 1.40, 95% CI 1.15-1.72). There was no interaction between NMB and VR for 28-day mortality. APACHE-III had a significant interaction with VR at baseline for the outcome of 28-day mortality, such that the relationship between VR and mortality was stronger among patients with lower APACHE-III. There was a significant association between rising VR trajectory and mortality that was independent of NMB, baseline PaO2/FiO2 ratio and generalized markers of disease severity (Adjusted OR 1.81, 95% CI 1.28-2.84 for 28-day and OR 2.07 95% CI 1.41-3.10 for 90-day mortality). APACHE-III and NMB were not effect modifiers in the relationship between VR trajectory and mortality.ConclusionsElevated baseline and day 1 VR were associated with higher 28-day mortality. The relationship between baseline VR and mortality was stronger among patients with lower APACHE-III. APACHE-III was not an effect modifier for the relationship between VR trajectory and mortality, so that the VR trajectory may be optimally suited for prognostication and predictive enrichment. VR was not different between patients randomized to NMB or control, indicating that VR can be utilized without correcting for NMB.
| S-EPMC9521854 | biostudies-literature
Project description:BackgroundVentilation/perfusion inequalities impair gas exchange in acute respiratory distress syndrome (ARDS). Although increased dead-space ventilation (VD/VT) has been described in ARDS, its mechanism is not clearly understood. We sought to evaluate the relationships between dynamic variations in VD/VT and extra-pulmonary microcirculatory blood flow detected at sublingual mucosa hypothesizing that an altered microcirculation, which is a generalized phenomenon during severe inflammatory conditions, could influence ventilation/perfusion mismatching manifested by increases in VD/VT fraction during early stages of ARDS.MethodsForty-two consecutive patients with early moderate and severe ARDS were included. PEEP was set targeting the best respiratory-system compliance after a PEEP-decremental recruitment maneuver. After 60 min of stabilization, hemodynamics and respiratory mechanics were recorded and blood gases collected. VD/VT was calculated from the CO2 production ([Formula: see text]) and CO2 exhaled fraction ([Formula: see text]) measurements by volumetric capnography. Sublingual microcirculatory images were simultaneously acquired using a sidestream dark-field device for an ulterior blinded semi-quantitative analysis. All measurements were repeated 24 h after.ResultsPercentage of small vessels perfused (PPV) and microcirculatory flow index (MFI) were inverse and significantly related to VD/VT at baseline (Spearman's rho = - 0.76 and - 0.63, p < 0.001; R2 = 0.63, and 0.48, p < 0.001, respectively) and 24 h after (Spearman's rho = - 0.71, and - 0.65; p < 0.001; R2 = 0.66 and 0.60, p < 0.001, respectively). Other respiratory, macro-hemodynamic and oxygenation parameters did not correlate with VD/VT. Variations in PPV between baseline and 24 h were inverse and significantly related to simultaneous changes in VD/VT (Spearman's rho = - 0.66, p < 0.001; R2 = 0.67, p < 0.001).ConclusionIncreased heterogeneity of microcirculatory blood flow evaluated at sublingual mucosa seems to be related to increases in VD/VT, while respiratory mechanics and oxygenation parameters do not. Whether there is a cause-effect relationship between microcirculatory dysfunction and dead-space ventilation in ARDS should be addressed in future research.
| S-EPMC7093634 | biostudies-literature
Project description:Physiologic dead space is a well-established independent predictor of death in patients with acute respiratory distress syndrome (ARDS). Here, we explore the association between a surrogate measure of dead space (DS) and early outcomes of mechanically ventilated patients admitted to Intensive Care Unit (ICU) because of COVID-19-associated ARDS. Retrospective cohort study on data derived from Italian ICUs during the first year of the COVID-19 epidemic. A competing risk Cox proportional hazard model was applied to test for the association of DS with two competing outcomes (death or discharge from the ICU) while adjusting for confounders. The final population consisted of 401 patients from seven ICUs. A significant association of DS with both death (HR 1.204; CI 1.019-1.423; p = 0.029) and discharge (HR 0.434; CI 0.414-0.456; p [Formula: see text]) was noticed even when correcting for confounding factors (age, sex, chronic obstructive pulmonary disease, diabetes, PaO[Formula: see text]/FiO[Formula: see text], tidal volume, positive end-expiratory pressure, and systolic blood pressure). These results confirm the important association between DS and death or ICU discharge in mechanically ventilated patients with COVID-19-associated ARDS. Further work is needed to identify the optimal role of DS monitoring in this setting and to understand the physiological mechanisms underlying these associations.
| S-EPMC10081332 | biostudies-literature
Project description:BackgroundMortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission.MethodsMulticenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes.ResultsOf the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47).ConclusionsHigher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation.
| S-EPMC8436582 | biostudies-literature
Project description:AbstractA high dead space (VD) to tidal volume (VT) ratio during peak exercise (VD/VTpeak) is a sensitive and consistent marker of gas exchange abnormalities; therefore, it is important in patients with chronic obstructive pulmonary disease (COPD). However, it is necessary to use invasive methods to obtain VD/VTpeak, as noninvasive methods, such as end-tidal PCO2 (PETCO2peak) and PETCO2 adjusted with Jones' equation (PJCO2peak) at peak exercise, have been reported to be inconsistent with arterial PCO2 at peak exercise (PaCO2peak). Hence, this study aimed to generate prediction equations for VD/VTpeak using statistical techniques, and to use PETCO2peak and PJCO2peak to calculate the corresponding VD/VTpeaks (i.e., VD/VTpeakETVD/VTpeakJ).A total of 46 male subjects diagnosed with COPD who underwent incremental cardiopulmonary exercise tests with PaCO2 measured via arterial catheterization were enrolled. Demographic data, blood laboratory tests, functional daily activities, chest radiography, two-dimensional echocardiography, and lung function tests were assessed.In multivariate analysis, diffusing capacity, vital capacity, mean inspiratory tidal flow, heart rate, and oxygen pulse at peak exercise were selected with a predictive power of 0.74. There were no significant differences in the PCO2peak values and the corresponding VD/VTpeak values across the three types (both p = NS).In subjects with COPD, VD/VTpeak can be estimated using statistical methods and the PETCO2peak and PJCO2peak. These methods may have similar predictive power and thus can be used in clinical practice.
| S-EPMC8830857 | biostudies-literature
Project description:BackgroundIt has been suggested that, in patients with CKD stage 5, measured GFR (mGFR), defined as the mean of urea and creatinine clearance, as measured by a 24-h urine collection, is a better measure of renal function than estimated GFR (eGFR), based on the CKD-EPI formula. This could be due to reduced muscle mass in this group. Its use is recommended in the ERBP guidelines. Unplanned dialysis initiation (DI) is associated with increased morbidity, mortality, and reduced modality choice and is generally considered undesirable. We hypothesized that the ratio mGFR/eGFR (M/E) aids prediction of death and DI.MethodsAll 24-h measurements of urea and creatinine excretion were extracted from the clinical biochemistry databases in Zealand. Data concerning renal diagnosis, comorbidity, biochemistry, medical treatment, mortality and date of DI, were extracted from patient notes, the National Patient Registry and the Danish Nephrology Registry. Patients were included if their eGFR was < 30 ml/min/1.73m2. The last available value for each patient was included. Follow-up was 12 months.ResultsOne thousand two hundred sixty-five patients were included. M/E was median 0.91 ± 0.43. It was highly correlated to previous determinations. It was negatively correlated to eGFR, comorbidity, high age and female sex. It was positively related to albumin and negatively to C-reactive protein. M/E was higher in patients treated with ACE inhibitors and diuretics but no other treatment groups. On a multivariate analysis, M/E was negatively correlated with mortality and combined mortality/DI, but not DI. A post hoc analysis showed a negative correlation to DI at 3 months. For patients with an eGFR 10-15 ml/min/1.73m2, combined mortality and DI at 3 months was for low M/E (< 0.75) 36%, medium (0.75-1.25) 20%, high (> 1.25) 8%. A low M/E predicted increased need for unplanned DI. A supplementary analysis in 519 patients where body surface area values were available, allowing BSA-corrected M/E to be analyzed, revealed similar results.ConclusionA low mGFR/eGFR ratio is associated with comorbidity, malnutrition, and inflammation. It is a marker of early DI, mortality, and unplanned dialysis initiation, independently of eGFR, age and comorbidity. Particular attention paid to patients with a low M/E may lower the incidence of unplanned dialysis requirement.
| S-EPMC8572425 | biostudies-literature