scholarly journals Trajectories of Hypoxemia & Pulmonary Mechanics of COVID-19 ARDS in the NorthCARDS Dataset

2021 ◽  
Author(s):  
Daniel Jafari ◽  
Amir Gandomi Sereshki ◽  
Alexander Makhnevich ◽  
Michael Qiu ◽  
Daniel Rolston ◽  
...  
Keyword(s):  
Multidisciplinary Team ◽  
Hospital Admissions ◽  
Lung Compliance ◽  
Pulmonary Mechanics ◽  
Normal Compliance ◽  
High Compliance

Abstract Background: Understanding heterogeneity seen in patients with COVIDARDS and comparing to non-COVIDARDS may inform tailored treatments.  Methods: A multidisciplinary team of frontline clinicians and data scientists worked to create the Northwell COVIDARDS dataset (NorthCARDS) leveraging over 11,542 COVID-19 hospital admissions. The data was then summarized to examine descriptive differences based on clinically meaningful categories of lung compliance, and to examine trends in oxygenation. Findings: Of the 1595 COVIDARDS patients in the NorthCARDS dataset, there were 538 (34·6%) who had very low lung compliance (<20ml/cmH2O), 982 (63·2%) with low-normal compliance (20-50ml/cmH2O), and 34 (2·2%) with high lung compliance (>50ml/cmH2O). The very low compliance group had double the median time to intubation compared to the low-normal group (107 hours (IQR 26·3, 238·3) vs. 37·9 hours (IQR 4·8, 90·7)). Overall, 67·5% (n=1049) of the patients died during the hospitalization. In comparison to non-COVIDARDS reports, there were less patients in the high compliance category (2.2%vs.12%, compliance ≥50mL/cmH20), and more patients with P/F ≤ 150 (57·8% vs. 45.6%). No correlation was apparent between lung compliance and P/F ratio. The Oxygenation Index was similar, (11·12(SD 5·67) vs.12·8(SD 10·8)).1 

On-Line Calculation of Pulmonary Mechanics by Digital Computer

1978 ◽  
Vol 17 (04) ◽  
pp. 261-272 ◽  
Author(s):  
Y. Brault ◽  
G. Atlan ◽  
H. Lorino ◽  
A. Harf ◽  
A.-M. Lorino ◽  
...  
Keyword(s):  
Time Pressure ◽  
Lung Compliance ◽  
Pulmonary Mechanics ◽  
Close Correspondence ◽  
Standard Equipment ◽  
On Demand ◽  
On Line ◽  
The Subject ◽  
Ventilatory Mechanics ◽  
Computerized System

A system was built up around a minicomputer to process in real time pressure and flow signals collected during the course of three ventilatory mechanics tests: the calculation of the lung volume, the evaluation of the static lung compliance, the analysis of the forced expiratory performance. The subject is seated in an open body Plethysmograph, which allows for the instantaneous calculation of changes in the volume of his thorax and abdomen. The system is controlled through a graphics console which displays the sampled curves and the results of data processing. In addition, the signals can be stored on demand onto a magnetic tape so that the method can be tested and improved off line. The results obtained in healthy volunteers are highly reproducible. A close correspondence is found both in patients and volunteers between computer-derived and hand-calculated results. The computerized system has become a standard equipment of our Lung Function Department, where it allows for a rapid quantitative analysis of lung volumes, lung elasticity and bronchial airflow.

Pulmonary mechanics during induced pulmonary edema in anesthetized dogs

1959 ◽  
Vol 14 (2) ◽  
pp. 177-186 ◽  
Author(s):  
C. D. Cook ◽  
J. Mead ◽  
G. L. Schreiner ◽  
N. R. Frank ◽  
J. M. Craig
Keyword(s):  
Pulmonary Edema ◽  
Lung Compliance ◽  
Tidal Range ◽  
Pulmonary Mechanics ◽  
Vascular Congestion ◽  
Anesthetized Dogs ◽  
Trapped Gas ◽  
Aortic Obstruction ◽  
Gas Volume ◽  
Normal Lungs

In order to study the mechanisms underlying the changes in the mechanical properties of the lungs during pulmonary edema, pulmonary vascular congestion was produced in spontaneously breathing, anesthetized dogs by partial aortic obstruction and intravenous infusion. Brief periods of congestion were associated with small changes in the lung compliance compared with the progressive and striking compliance reduction (-78%) noted with more prolonged congestion. Lung volume at end-expiration showed little change if edema fluid and trapped gas as well as the ventilated gas volume were taken into account. When edematous lungs were forcibly inflated beyond the tidal range, it was found that the overall compliance at a distending pressure of 30 cm H2O was not much less (-6%) than that of normal lungs. Furthermore, edematous lungs manifested marked ‘static’ hysteresis during such maneuvers. These findings suggested that surface phenomena were responsible for the mechanical behavior of edematous lungs rather than vascular congestion, per se, or intrinsic tissue changes. This was borne out by experiments on excised lungs which showed that the elastic properties of edematous lungs were not significantly different from normal lungs when surface forces were minimized. Submitted on August 25, 1958

scholarly journals Shrinking Lung Syndrome as a Manifestation of Pleuritis: A New Model Based on Pulmonary Physiological Studies

2013 ◽  
Vol 40 (3) ◽  
pp. 273-281 ◽  
Author(s):  
LAUREN A. HENDERSON ◽  
STEPHEN H. LORING ◽  
RITU R. GILL ◽  
KATHERINE P. LIAO ◽  
RUMEY ISHIZAWAR ◽  
...  
Keyword(s):  
Lung Compliance ◽  
Structural Basis ◽  
Pulmonary Mechanics ◽  
Deep Inspiration ◽  
Chest Imaging ◽  
Lung Volumes ◽  
Imaging Results ◽  
Physiological Abnormalities ◽  
Parenchymal Disease ◽  
Tomography Data

Objective.The pathophysiology of shrinking lung syndrome (SLS) is poorly understood. We sought to define the structural basis for this condition through the study of pulmonary mechanics in affected patients.Methods.Since 2007, most patients evaluated for SLS at our institutions have undergone standardized respiratory testing including esophageal manometry. We analyzed these studies to define the physiological abnormalities driving respiratory restriction. Chest computed tomography data were post-processed to quantify lung volume and parenchymal density.Results.Six cases met criteria for SLS. All presented with dyspnea as well as pleurisy and/or transient pleural effusions. Chest imaging results were free of parenchymal disease and corrected diffusing capacities were normal. Total lung capacities were 39%–50% of predicted. Maximal inspiratory pressures were impaired at high lung volumes, but not low lung volumes, in 5 patients. Lung compliance was strikingly reduced in all patients, accompanied by increased parenchymal density.Conclusion.Patients with SLS exhibited symptomatic and/or radiographic pleuritis associated with 2 characteristic physiological abnormalities: (1) impaired respiratory force at high but not low lung volumes; and (2) markedly decreased pulmonary compliance in the absence of identifiable interstitial lung disease. These findings suggest a model in which pleural inflammation chronically impairs deep inspiration, for example through neural reflexes, leading to parenchymal reorganization that impairs lung compliance, a known complication of persistently low lung volumes. Together these processes could account for the association of SLS with pleuritis as well as the gradual symptomatic and functional progression that is a hallmark of this syndrome.

scholarly journals Specialist palliative care, psychology, interstitial lung disease (ILD) multidisciplinary team meeting: a novel model to address palliative care needs

2018 ◽  
Vol 5 (1) ◽  
pp. e000360 ◽  
Author(s):  
Shaney L Barratt ◽  
Michelle Morales ◽  
Toby Speirs ◽  
Khaled Al Jboor ◽  
Heather Lamb ◽  
...  
Keyword(s):  
Palliative Care ◽  
Interstitial Lung Disease ◽  
Lung Disease ◽  
Multidisciplinary Team ◽  
Hospital Admissions ◽  
Models Of Care ◽  
Specialist Care ◽  
Care Needs ◽  
Unplanned Hospital Admissions ◽  
Palliative Care Needs

IntroductionPatients with progressive idiopathic fibrotic interstitial lung disease (ILD), such as those with idiopathic pulmonary fibrosis (IPF), can have an aggressive disease course, with a median survival of only 3–5 years from diagnosis. The palliative care needs of these patients are often unmet. There are calls for new models of care, whereby the patient’s usual respiratory clinician remains central to the integration of palliative care principles and practices into their patient’s management, but the optimal model of service delivery has yet to be determined.MethodsWe developed a novel, collaborative, multidisciplinary team (MDT) meeting between our palliative care, psychology and ILD teams with the principal aim of integrating specialist care to ensure the needs of persons with ILD, and their caregivers were identified and met by referral to the appropriate service. The objective of this study was to assess the effectiveness of this novel MDT meeting on the assessment of a patient’s palliative care needs.ResultsSignificant increases in advance care planning discussions were observed, in conjunction with increased referrals to community courses and teams, following introduction of this novel MDT.ConclusionsOur results suggest that our collaborative MDT is an effective platform to address patients’ unmet palliative care needs. Further work is required to explore the effect of our model on achieving the preferred place of death and reductions in unplanned hospital admissions.

scholarly journals COVID-19 and delivery of difficult asthma services

2021 ◽  
pp. archdischild-2021-322335
Author(s):  
Anna-Louise Nichols ◽  
Mayank Sonnappa-Naik ◽  
Laura Gardner ◽  
Charlotte Richardson ◽  
Natalie Orr ◽  
...  
Keyword(s):  
Hospital Admission ◽  
Multidisciplinary Team ◽  
Hospital Admissions ◽  
Forced Expiratory Volume ◽  
Acute Hospital ◽  
Attendance Rates ◽  
Face To Face ◽  
Admission Rates ◽  
Oral Corticosteroids ◽  
Difficult Asthma

The COVID-19 pandemic necessitated an urgent reconfiguration of our difficult asthma (DA) service. We rapidly switched to virtual clinics and rolled out home spirometry based on clinical need. From March to August 2020, 110 patients with DA (68% virtually) were seen in clinic, compared with March–August 2019 when 88 patients were seen face-to-face. There was DA clinic cancellation/non-attendance (16% vs 43%; p<0.0003). In patients with home spirometers, acute hospital admissions (6 vs 26; p<0.01) from March to August 2020 were significantly lower compared with the same period in 2019. There was no difference in the number of courses of oral corticosteroids or antibiotics prescribed (47 vs 53; p=0.81). From April to August 2020, 50 patients with DA performed 253 home spirometry measurements, of which 39 demonstrated >20% decrease in forced expiratory volume in 1 s, resulting in new action plans in 87% of these episodes. In our DA cohort, we demonstrate better attendance rates at virtual multidisciplinary team consultations and reduced hospital admission rates when augmented with home spirometry monitoring.

Ovalbumin-induced lung disease in the pony: role of vagal mechanisms

1982 ◽  
Vol 53 (3) ◽  
pp. 719-725 ◽  
Author(s):  
F. J. Derksen ◽  
N. E. Robinson ◽  
R. F. Slocombe
Keyword(s):  
Respiratory System ◽  
Minute Ventilation ◽  
Left Lung ◽  
Arterial Oxygen Tension ◽  
Lung Compliance ◽  
Arterial Oxygen ◽  
Pulmonary Mechanics ◽  
Vagal Blockade ◽  
Before And After ◽  
Respiratory System Resistance

In awake sensitized ponies, we studied the effect of aerosol ovalbumin challenge on ventilation, pulmonary mechanics, lung volume, and gas exchange before and after vagal blockade. We also challenged the left lung and measured respiratory rate (f) and right and left respiratory system resistance (RrsR, RrsL) before and after both left and bilateral vagal section. Bilateral ovalbumin aerosol challenge increased f, minute ventilation (VE), total respiratory system resistance (Rrs), and minimal volume, decreased dynamic compliance, total lung capacity, and arterial oxygen tension, and was without effect on tidal volume (VT), functional residual capacity, quasi-static lung compliance, and arterial carbon dioxide tension. Vagal blockade reversed the increase in f, VE, and Rrs and increased VT. Challenge of the left lung increased f and RrsL but did not alter RrsR. Bilateral vagal section reversed the tachypnea but unilateral section did not. Histopathologic lesions included acute fibrinopurulent obstructive bronchiolitis, bronchitis, edema, and alveolar distension. We conclude that local mechanisms are of critical importance in the pathogenesis of ovalbumin-induced airway obstruction in ponies, that increased sensitivity of airway smooth muscle to normal vagal tone may also play a role, and that tachypnea following challenge is caused by activity of pulmonary receptors with vagal afferent fibers.

Neck and Body Position Effects on Pulmonary Mechanics in Infants

PEDIATRICS ◽  
1989 ◽  
Vol 84 (4) ◽  
pp. 670-674
Author(s):  
Waldemar A. Carlo ◽  
Aris Beoglos ◽  
Bonnie S. Siner ◽  
Richard J. Martin
Keyword(s):  
Bronchopulmonary Dysplasia ◽  
Body Position ◽  
Clinical Status ◽  
Lung Compliance ◽  
Assisted Ventilation ◽  
Pulmonary Mechanics ◽  
Neck Flexion ◽  
Position Effects ◽  
Postural Changes ◽  
Residual Capacity

Pulmonary mechanics and ventilatory parameters were measured in 30 former preterm infants at a postterm age of 8 to 10 months. All subjects had required assisted ventilation in the neonatal period and 16 had a history of bronchopulmonary dysplasia. Each infant was studied in both supine and semisitting positions, and in each body position the infants were studied with neutral, flexed, and extended neck positions. Baseline measurements (body supine, neck neutral) and the responses to postural changes did not differ between infants who had had bronchopulmonary dysplasia and those who had not. Change in body position from supine to semisitting decreased total pulmonary resistance (P &lt; .05) and increased specific lung compliance (P &lt; .01). Neck flexion increased resistance (P &lt; .0001) in both body positions but did not influence compliance. These postural effects are consistent with an increase in functional residual capacity in the semisitting position and a decrease in pharyngeal area during neck flexion. Thus, posture needs to be precisely controlled during pulmonary function testing in infants. Furthermore, optimal neck and body position may improve their clinical status.

Reversal of 5HT-induced bronchoconstriction by PGI2: distribution of central and peripheral actions

1980 ◽  
Vol 49 (3) ◽  
pp. 521-527 ◽  
Author(s):  
E. W. Spannhake ◽  
J. L. Levin ◽  
B. T. Mellion ◽  
C. A. Gruetter ◽  
A. L. Hyman ◽  
...  
Keyword(s):  
Lung Compliance ◽  
Pulmonary Mechanics ◽  
Similar Distribution ◽  
Mechanically Ventilated ◽  
Peripheral Airways ◽  
Bolus Intravenous Injection ◽  
Peripheral Areas ◽  
Dynamic Lung Compliance ◽  
Dose Dependent

In anesthetized, mechanically ventilated, and vagotomized cats, we studied the distribution of the bronchodilatory effects of prostaglandin I2 (PGI2) in central and peripheral airways. In the intact-chest cat, bolus intravenous injection of PGI2 in a range of doses from 3 to 100 micrograms produced dose-dependent reversal of 5-hydroxytryptamine- (5HT) induced bronchoconstriction. Bronchodilatory effects were manifested by a pronounced decrease in central airways flow resistance, as estimated by measurement of lung resistance and by an increase in dynamic lung compliance (Cdyn). A similar distribution and magnitude of airway effects were produced by intravenous administration of PGE1 in a range of doses from 0.3 to 10 micrograms. PGI2 significantly reversed the frequency dependence of compliance induced by infusion of 5HT. The PGI2 metabolite, 6-keto-PGF1 alpha, was without effect on pulmonary mechanics. Comparison of right- versus left-heart administration of PGI2 did not point to a significant role of the bronchial circulation in the airway effects of PGI2. Comparison of the effects of PGI2 and PGE1 on cat bronchial and parenchymal strips contracted by 5HT showed both prostaglandins to have predominant action on bronchial smooth muscle with PGI2 being 3-10 times less active than PGE1. These data suggest that PGI2 has central airway bronchodilator activity, similar to, but less potent than PGE1. In addition, they suggest that PGI2 has significant dilator activity in certain peripheral areas of the lung, as well.

Pulmonary mechanics during the ventilatory response to hypoxemia in the newborn monkey

1983 ◽  
Vol 55 (3) ◽  
pp. 1008-1014 ◽  
Author(s):  
W. A. LaFramboise ◽  
R. D. Guthrie ◽  
T. A. Standaert ◽  
D. E. Woodrum
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Lung Compliance ◽  
Pulmonary Mechanics ◽  
Base Line ◽  
Respiratory Drive ◽  
Pulmonary Resistance ◽  
Residual Capacity ◽  
Dynamic Lung Compliance ◽  
Sustained Increase

Dynamic lung compliance (CL), inspiratory pulmonary resistance (RL), and functional residual capacity (FRC) were measured in 10 unanesthetized 48 h-old newborn monkeys and seven 21-day-old infant monkeys during acute exposures to an equivalent level of hypoxemia. End-expiratory airway occlusions were performed and the pressure developed by 200 ms (P0.2) was utilized as an index of central respiratory drive. P0.2 demonstrated a sustained increase throughout the period of hypoxemia on day 2 despite the fact that minute ventilation (VI) initially increased but then fell back to base-line levels. Dynamic lung compliance fell and FRC increased by 5 min of hypoxemia in the newborns. The 21-day-old monkeys exhibited a sustained increase in both VI and P0.2 throughout the hypoxic period with no change in CL and FRC. RL did not change at either postnatal age during hypoxemia. These data indicate that the neonatal monkey is subject to changes in pulmonary mechanics (decreased CL and increased FRC) during hypoxemia and that these changes are eliminated with maturation.

scholarly journals Association between lung compliance phenotypes and mortality in COVID-19 patients with acute respiratory distress syndrome

2021 ◽  
Vol 50 (9) ◽  
pp. 686-694
Author(s):  
Ser Hon Puah ◽  
Matthew Edward Cove ◽  
Jason Phua ◽  
Amit Kansal ◽  
Jonathen Venkatachalam ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Invasive Mechanical Ventilation ◽  
Lung Compliance ◽  
High Compliance ◽  
Factors Associated ◽  
Risk Of Death

ABSTRACT Introduction: Acute respiratory distress syndrome (ARDS) in COVID-19 is associated with a high mortality rate, though outcomes of the different lung compliance phenotypes are unclear. We aimed to measure lung compliance and examine other factors associated with mortality in COVID-19 patients with ARDS. Methods: Adult patients with COVID-19 ARDS who required invasive mechanical ventilation at 8 hospitals in Singapore were prospectively enrolled. Factors associated with both mortality and differences between high (<40mL/cm H2O) and low (<40mL/cm H2O) compliance were analysed. Results: A total of 102 patients with COVID-19 who required invasive mechanical ventilation were analysed; 15 (14.7%) did not survive. Non-survivors were older (median 70 years, interquartile range [IQR] 67–75 versus median 61 years, IQR 52–66; P<0.01), and required a longer duration of ventilation (26 days, IQR 12–27 vs 8 days, IQR 5–15; P<0.01) and intensive care unit support (26 days, IQR 11–30 vs 11.5 days, IQR 7–17.3; P=0.01), with a higher incidence of acute kidney injury (15 patients [100%] vs 40 patients [46%]; P<0.01). There were 67 patients who had lung compliance data; 24 (35.8%) were classified as having high compliance and 43 (64.2%) as having low compliance. Mortality was higher in patients with high compliance (33.3% vs 11.6%; P=0.03), and was associated with a drop in compliance at day 7 (-9.3mL/cm H2O (IQR -4.5 to -15.4) vs 0.2mL/cm H2O (4.7 to -5.2) P=0.04). Conclusion: COVID-19 ARDS patients with higher compliance on the day of intubation and a longitudinal decrease over time had a higher risk of death. Keywords: ARDS, COVID-19-associated respiratory failure, high-flow nasal cannula therapy, HFNC, post-intubation, ventilation strategies

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