Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 13 de 13
Filter
2.
Crit Care ; 25(1): 199, 2021 06 09.
Article in English | MEDLINE | ID: covidwho-1262513

ABSTRACT

BACKGROUND: Heterogeneous respiratory system static compliance (CRS) values and levels of hypoxemia in patients with novel coronavirus disease (COVID-19) requiring mechanical ventilation have been reported in previous small-case series or studies conducted at a national level. METHODS: We designed a retrospective observational cohort study with rapid data gathering from the international COVID-19 Critical Care Consortium study to comprehensively describe CRS-calculated as: tidal volume/[airway plateau pressure-positive end-expiratory pressure (PEEP)]-and its association with ventilatory management and outcomes of COVID-19 patients on mechanical ventilation (MV), admitted to intensive care units (ICU) worldwide. RESULTS: We studied 745 patients from 22 countries, who required admission to the ICU and MV from January 14 to December 31, 2020, and presented at least one value of CRS within the first seven days of MV. Median (IQR) age was 62 (52-71), patients were predominantly males (68%) and from Europe/North and South America (88%). CRS, within 48 h from endotracheal intubation, was available in 649 patients and was neither associated with the duration from onset of symptoms to commencement of MV (p = 0.417) nor with PaO2/FiO2 (p = 0.100). Females presented lower CRS than males (95% CI of CRS difference between females-males: - 11.8 to - 7.4 mL/cmH2O p < 0.001), and although females presented higher body mass index (BMI), association of BMI with CRS was marginal (p = 0.139). Ventilatory management varied across CRS range, resulting in a significant association between CRS and driving pressure (estimated decrease - 0.31 cmH2O/L per mL/cmH20 of CRS, 95% CI - 0.48 to - 0.14, p < 0.001). Overall, 28-day ICU mortality, accounting for the competing risk of being discharged within the period, was 35.6% (SE 1.7). Cox proportional hazard analysis demonstrated that CRS (+ 10 mL/cm H2O) was only associated with being discharge from the ICU within 28 days (HR 1.14, 95% CI 1.02-1.28, p = 0.018). CONCLUSIONS: This multicentre report provides a comprehensive account of CRS in COVID-19 patients on MV. CRS measured within 48 h from commencement of MV has marginal predictive value for 28-day mortality, but was associated with being discharged from ICU within the same period. Trial documentation: Available at https://www.covid-critical.com/study . TRIAL REGISTRATION: ACTRN12620000421932.


Subject(s)
COVID-19/complications , COVID-19/therapy , Lung Compliance/physiology , Respiration, Artificial/methods , Respiratory Distress Syndrome/etiology , Respiratory Distress Syndrome/therapy , Adult , Cohort Studies , Critical Care/methods , Europe , Female , Humans , Intensive Care Units , Male , Middle Aged , Retrospective Studies , Severity of Illness Index
3.
A A Pract ; 15(3): e01392, 2021 Mar 09.
Article in English | MEDLINE | ID: covidwho-1151699

ABSTRACT

Ventilator shortages occurred due to the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This in vitro study evaluated the effectiveness of 3-dimensional (3D)-printed splitters and 3D-printed air flow limiters (AFL) in delivering appropriate tidal volumes (TV) to lungs with different compliances. Groups were divided according to the size of the AFL: AFL-4 was a 4-mm device, AFL-5 a 5-mm device, AFL-6 a 6-mm device, and no limiter (control). A ventilator was split to supply TV to 2 artificial lungs with different compliances. The AFL improved TV distribution.


Subject(s)
COVID-19/epidemiology , COVID-19/therapy , Emergency Medical Services/methods , Lung Compliance/physiology , Printing, Three-Dimensional , Ventilators, Mechanical/supply & distribution , Humans , Lung/physiology , Male , Tidal Volume/physiology
4.
Eur J Heart Fail ; 22(12): 2228-2237, 2020 12.
Article in English | MEDLINE | ID: covidwho-965861

ABSTRACT

AIMS: Interstitial pneumonia due to coronavirus disease 2019 (COVID-19) is often complicated by severe respiratory failure. In addition to reduced lung compliance and ventilation/perfusion mismatch, a blunted hypoxic pulmonary vasoconstriction has been hypothesized, that could explain part of the peculiar pathophysiology of the COVID-19 cardiorespiratory syndrome. However, no invasive haemodynamic characterization of COVID-19 patients has been reported so far. METHODS AND RESULTS: Twenty-one mechanically-ventilated COVID-19 patients underwent right heart catheterization. Their data were compared both with those obtained from non-mechanically ventilated paired control subjects matched for age, sex and body mass index, and with pooled data of 1937 patients with 'typical' acute respiratory distress syndrome (ARDS) from a systematic literature review. Cardiac index was higher in COVID-19 patients than in controls [3.8 (2.7-4.5) vs. 2.4 (2.1-2.8) L/min/m2 , P < 0.001], but slightly lower than in ARDS patients (P = 0.024). Intrapulmonary shunt and lung compliance were inversely related in COVID-19 patients (r = -0.57, P = 0.011) and did not differ from ARDS patients. Despite this, pulmonary vascular resistance of COVID-19 patients was normal, similar to that of control subjects [1.6 (1.1-2.5) vs. 1.6 (0.9-2.0) WU, P = 0.343], and lower than reported in ARDS patients (P < 0.01). Pulmonary hypertension was present in 76% of COVID-19 patients and in 19% of control subjects (P < 0.001), and it was always post-capillary. Pulmonary artery wedge pressure was higher in COVID-19 than in ARDS patients, and inversely related to lung compliance (r = -0.46, P = 0.038). CONCLUSIONS: The haemodynamic profile of COVID-19 patients needing mechanical ventilation is characterized by combined cardiopulmonary alterations. Low pulmonary vascular resistance, coherent with a blunted hypoxic vasoconstriction, is associated with high cardiac output and post-capillary pulmonary hypertension, that could eventually contribute to lung stiffness and promote a vicious circle between the lung and the heart.


Subject(s)
COVID-19/physiopathology , Hemodynamics/physiology , Hypertension, Pulmonary/physiopathology , Hypoxia/physiopathology , Respiratory Distress Syndrome/physiopathology , Vascular Resistance/physiology , Vasoconstriction/physiology , Aged , COVID-19/therapy , Cardiac Catheterization , Cardiac Output/physiology , Case-Control Studies , Echocardiography , Female , Humans , Hypoxia/therapy , Lung Compliance/physiology , Male , Middle Aged , Respiration, Artificial , Respiratory Distress Syndrome/therapy , Retrospective Studies , SARS-CoV-2 , Ventilation-Perfusion Ratio
5.
Intensive Care Med ; 46(12): 2385-2396, 2020 12.
Article in English | MEDLINE | ID: covidwho-917110

ABSTRACT

In ARDS patients, the change from supine to prone position generates a more even distribution of the gas-tissue ratios along the dependent-nondependent axis and a more homogeneous distribution of lung stress and strain. The change to prone position is generally accompanied by a marked improvement in arterial blood gases, which is mainly due to a better overall ventilation/perfusion matching. Improvement in oxygenation and reduction in mortality are the main reasons to implement prone position in patients with ARDS. The main reason explaining a decreased mortality is less overdistension in non-dependent lung regions and less cyclical opening and closing in dependent lung regions. The only absolute contraindication for implementing prone position is an unstable spinal fracture. The maneuver to change from supine to prone and vice versa requires a skilled team of 4-5 caregivers. The most frequent adverse events are pressure sores and facial edema. Recently, the use of prone position has been extended to non-intubated spontaneously breathing patients affected with COVID-19 ARDS. The effects of this intervention on outcomes are still uncertain.


Subject(s)
Prone Position/physiology , Respiratory Distress Syndrome/physiopathology , Respiratory Mechanics/physiology , Humans , Lung Compliance/drug effects , Lung Compliance/physiology , Respiratory Distress Syndrome/complications
6.
Am J Respir Crit Care Med ; 202(9): 1244-1252, 2020 11 01.
Article in English | MEDLINE | ID: covidwho-901518

ABSTRACT

Rationale: A novel model of phenotypes based on set thresholds of respiratory system compliance (Crs) was recently postulated in context of coronavirus disease (COVID-19) acute respiratory distress syndrome (ARDS). In particular, the dissociation between the degree of hypoxemia and Crs was characterized as a distinct ARDS phenotype.Objectives: To determine whether such Crs-based phenotypes existed among patients with ARDS before the COVID-19 pandemic and to closely examine the Crs-mortality relationship.Methods: We undertook a secondary analysis of patients with ARDS, who were invasively ventilated on controlled modes and enrolled in a large, multinational, epidemiological study. We assessed Crs, degree of hypoxemia, and associated Crs-based phenotypic patterns with their characteristics and outcomes.Measurements and Main Results: Among 1,117 patients with ARDS who met inclusion criteria, the median Crs was 30 (interquartile range, 23-40) ml/cm H2O. One hundred thirty-six (12%) patients had preserved Crs (≥50 ml/cm H2O; phenotype with low elastance ["phenotype L"]), and 827 (74%) patients had poor Crs (<40 ml/cm H2O; phenotype with high elastance ["phenotype H"]). Compared with those with phenotype L, patients with phenotype H were sicker and had more comorbidities and higher hospital mortality (32% vs. 45%; P < 0.05). A near complete dissociation between PaO2/FiO2 and Crs was observed. Of 136 patients with phenotype L, 58 (43%) had a PaO2/FiO2 < 150. In a multivariable-adjusted analysis, the Crs was independently associated with hospital mortality (adjusted odds ratio per ml/cm H2O increase, 0.988; 95% confidence interval, 0.979-0.996; P = 0.005).Conclusions: A wide range of Crs was observed in non-COVID-19 ARDS. Approximately one in eight patients had preserved Crs. PaO2/FiO2 and Crs were dissociated. Lower Crs was independently associated with higher mortality. The Crs-mortality relationship lacked a clear transition threshold.


Subject(s)
Betacoronavirus , Coronavirus Infections/epidemiology , Lung Compliance/physiology , Pandemics , Pneumonia, Viral/epidemiology , Respiratory Distress Syndrome/physiopathology , COVID-19 , Female , Follow-Up Studies , Humans , Intensive Care Units , Male , Middle Aged , Prospective Studies , Respiratory Function Tests , SARS-CoV-2
7.
Intensive Care Med ; 46(12): 2187-2196, 2020 12.
Article in English | MEDLINE | ID: covidwho-886981

ABSTRACT

PURPOSE: To investigate whether COVID-19-ARDS differs from all-cause ARDS. METHODS: Thirty-two consecutive, mechanically ventilated COVID-19-ARDS patients were compared to two historical ARDS sub-populations 1:1 matched for PaO2/FiO2 or for compliance of the respiratory system. Gas exchange, hemodynamics and respiratory mechanics were recorded at 5 and 15 cmH2O PEEP. CT scan variables were measured at 5 cmH2O PEEP. RESULTS: Anthropometric characteristics were similar in COVID-19-ARDS, PaO2/FiO2-matched-ARDS and Compliance-matched-ARDS. The PaO2/FiO2-matched-ARDS and COVID-19-ARDS populations (both with PaO2/FiO2 106 ± 59 mmHg) had different respiratory system compliances (Crs) (39 ± 11 vs 49.9 ± 15.4 ml/cmH2O, p = 0.03). The Compliance-matched-ARDS and COVID-19-ARDS had similar Crs (50.1 ± 15.7 and 49.9 ± 15.4 ml/cmH2O, respectively) but significantly lower PaO2/FiO2 for the same Crs (160 ± 62 vs 106.5 ± 59.6 mmHg, p < 0.001). The three populations had similar lung weights but COVID-19-ARDS had significantly higher lung gas volume (PaO2/FiO2-matched-ARDS 930 ± 644 ml, COVID-19-ARDS 1670 ± 791 ml and Compliance-matched-ARDS 1301 ± 627 ml, p < 0.05). The venous admixture was significantly related to the non-aerated tissue in PaO2/FiO2-matched-ARDS and Compliance-matched-ARDS (p < 0.001) but unrelated in COVID-19-ARDS (p = 0.75), suggesting that hypoxemia was not only due to the extent of non-aerated tissue. Increasing PEEP from 5 to 15 cmH2O improved oxygenation in all groups. However, while lung mechanics and dead space improved in PaO2/FiO2-matched-ARDS, suggesting recruitment as primary mechanism, they remained unmodified or worsened in COVID-19-ARDS and Compliance-matched-ARDS, suggesting lower recruitment potential and/or blood flow redistribution. CONCLUSIONS: COVID-19-ARDS is a subset of ARDS characterized overall by higher compliance and lung gas volume for a given PaO2/FiO2, at least when considered within the timeframe of our study.


Subject(s)
COVID-19/physiopathology , Respiratory Distress Syndrome/physiopathology , Adult , Aged , Blood Gas Analysis/methods , COVID-19/therapy , Cohort Studies , Female , Humans , Intensive Care Units/organization & administration , Intensive Care Units/statistics & numerical data , Italy , Length of Stay/statistics & numerical data , Lung Compliance/physiology , Male , Middle Aged , Prospective Studies , Pulmonary Gas Exchange/physiology , Respiratory Distress Syndrome/therapy , Simplified Acute Physiology Score , Tomography, X-Ray Computed/methods
8.
Respir Care ; 65(7): 920-931, 2020 07.
Article in English | MEDLINE | ID: covidwho-840991

ABSTRACT

BACKGROUND: The overwhelming demand for mechanical ventilators due to COVID-19 has stimulated interest in using one ventilator for multiple patients (ie, multiplex ventilation). Despite a plethora of information on the internet, there is little supporting evidence and no human studies. The risk of multiplex ventilation is that ventilation and PEEP effects are largely uncontrollable and depend on the difference between patients' resistance and compliance. It is not clear whether volume control ventilation or pressure control ventilation is safer or more effective. We designed a simulation-based study to allow complete control over the relevant variables to determine the effects of various degrees of resistance-compliance imbalance on tidal volume (VT), end-expiratory lung volume (EELV), and imputed pH. METHODS: Two separate breathing simulators were ventilated with a ventilator using pressure control and volume control ventilation modes. Evidence-based lung models simulated a range of differences in resistance and compliance (6 pairs of simulated patients). Differences in VT, EELV, and imputed pH were recorded. RESULTS: Depending on differences in resistance and compliance, differences in VT ranged from 1% (with equal resistance and compliance) to 79%. Differences in EELV ranged from 2% to 109%, whereas differences in pH ranged from 0% to 5%. Failure due to excessive VT (ie, > 8 mL/kg) did not occur, but failure due to excessive EELV difference (ie, > 10%) was evident in 50% of patient pairs. There was no difference in failure rate between volume control and pressure control ventilation modes. CONCLUSIONS: These experiments confirmed the potential for markedly different ventilation and oxygenation for patients with uneven respiratory system impedances during multiplex ventilation. Three critical problems must be solved to minimize risk: (1) partitioning of inspiratory flow from the ventilator individually between the 2 patients, (2) measurement of VT delivered to each patient, and (3) provision for individual PEEP. We provide suggestions for solving these problems.


Subject(s)
Airway Resistance/physiology , Coronavirus Infections , Lung Compliance/physiology , Materials Testing/methods , Pandemics , Pneumonia, Viral , Respiration, Artificial , Betacoronavirus , COVID-19 , Computer Simulation , Coronavirus Infections/epidemiology , Coronavirus Infections/therapy , Critical Care/methods , Equipment Design , Humans , Models, Biological , Pneumonia, Viral/epidemiology , Pneumonia, Viral/therapy , Respiration, Artificial/instrumentation , Respiration, Artificial/methods , SARS-CoV-2 , Ventilators, Mechanical/standards , Ventilators, Mechanical/supply & distribution
9.
Expert Rev Respir Med ; 15(2): 183-195, 2021 02.
Article in English | MEDLINE | ID: covidwho-752298

ABSTRACT

INTRODUCTION: The exponential growth of SARS-CoV-2 virus transmission during the first months of 2020 has placed substantial pressure on most health systems around the world. The complications derived from the novel coronavirus disease (COVID-19) vary due to comorbidities, sex and age, with more than 50% of the patients requiring some level of intensive care developing acute respiratory distress syndrome (ARDS). The authors carried out an extensive and comprehensive literature review on SARS-CoV-2 infection, the clinical, pathological, and radiological presentation as well as the current treatment strategies. AREAS COVERED: Various complications caused by SARS-CoV-2 infection have been identified, the most lethal being the acute respiratory distress syndrome, caused most likely by the presence of severe immune cell response and the concomitant alveolus inflammation. The new treatment strategies are updated, and the analysis of the physiopathology is included in this review. EXPERT OPINION: ARDS is one of the most frequent complications in patients with COVID-19. Information regarding the etiology and physiopathology are still unfolding and for the prevention and amelioration, good clinical management, adequate ventilatory support and the use of systemic corticoids seem to be the most efficient way to reduce mortality and to reduce hospital lengths.


Subject(s)
COVID-19/physiopathology , Respiratory Distress Syndrome/diagnosis , Respiratory Distress Syndrome/therapy , Analgesics/therapeutic use , Antiviral Agents/therapeutic use , COVID-19/diagnosis , COVID-19/therapy , Continuous Positive Airway Pressure , Cytokines/metabolism , Drug Repositioning , Humans , Hypoxia/physiopathology , Lung/diagnostic imaging , Lung Compliance/physiology , Noninvasive Ventilation , Oxygen Inhalation Therapy , Phenotype , Respiration, Artificial , Respiratory Distress Syndrome/epidemiology , Respiratory Distress Syndrome/virology , Respiratory Function Tests , SARS-CoV-2 , Thrombosis/physiopathology , Virus Replication/physiology
10.
Thorax ; 76(2): 182-184, 2021 02.
Article in English | MEDLINE | ID: covidwho-733132

ABSTRACT

An increasing observation is that some patients with COVID-19 have normal lung compliance but significant hypoxaemia different from typical acute respiratory distress syndrome (ARDS). We hypothesised that changes in pulmonary blood distribution may be partially responsible and used functional respiratory imaging on CT scans to calculate pulmonary blood volume. We found that patients with COVID-19 had significantly reduced blood volume in the smaller calibre blood vessels (here defined as <5 mm2 cross-sectional area) compared with matched ARDS patients and healthy controls. This suggests that using high levels of PEEP may not alone be enough to oxygenate these patients and that additional management strategies may be needed.


Subject(s)
COVID-19/physiopathology , Lung Compliance/physiology , Lung/physiopathology , Pulmonary Circulation/physiology , Respiratory Mechanics/physiology , SARS-CoV-2 , COVID-19/diagnosis , COVID-19/epidemiology , Humans , Pandemics , Respiratory Function Tests , Retrospective Studies , Tomography, X-Ray Computed
SELECTION OF CITATIONS
SEARCH DETAIL