scholarly journals Breath-holding as a novel approach to risk stratification in COVID-19

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Ludovico Messineo ◽  
Elisa Perger ◽  
Luciano Corda ◽  
Simon A. Joosten ◽  
Francesco Fanfulla ◽  
...  
Keyword(s):  
Respiratory Failure ◽  
Gas Exchange ◽  
Ventilatory Support ◽  
Adverse Outcomes ◽  
Breath Holding ◽  
Breath Hold ◽  
Ratio Test ◽  
Healthy Controls ◽  
Composite Outcome ◽  
Ventilatory Control

Abstract Background Despite considerable progress, it remains unclear why some patients admitted for COVID-19 develop adverse outcomes while others recover spontaneously. Clues may lie with the predisposition to hypoxemia or unexpected absence of dyspnea (‘silent hypoxemia’) in some patients who later develop respiratory failure. Using a recently-validated breath-holding technique, we sought to test the hypothesis that gas exchange and ventilatory control deficits observed at admission are associated with subsequent adverse COVID-19 outcomes (composite primary outcome: non-invasive ventilatory support, intensive care admission, or death). Methods Patients with COVID-19 (N = 50) performed breath-holds to obtain measurements reflecting the predisposition to oxygen desaturation (mean desaturation after 20-s) and reduced chemosensitivity to hypoxic-hypercapnia (including maximal breath-hold duration). Associations with the primary composite outcome were modeled adjusting for baseline oxygen saturation, obesity, sex, age, and prior cardiovascular disease. Healthy controls (N = 23) provided a normative comparison. Results The adverse composite outcome (observed in N = 11/50) was associated with breath-holding measures at admission (likelihood ratio test, p = 0.020); specifically, greater mean desaturation (12-fold greater odds of adverse composite outcome with 4% compared with 2% desaturation, p = 0.002) and greater maximal breath-holding duration (2.7-fold greater odds per 10-s increase, p = 0.036). COVID-19 patients who did not develop the adverse composite outcome had similar mean desaturation to healthy controls. Conclusions Breath-holding offers a novel method to identify patients with high risk of respiratory failure in COVID-19. Greater breath-hold induced desaturation (gas exchange deficit) and greater breath-holding tolerance (ventilatory control deficit) may be independent harbingers of progression to severe disease.

Effect of Bronchoalveolar Lavage on Gas Exchange in Patients with Diffuse Lung Disease and Respiratory Failure

1992 ◽  
Vol 7 (3) ◽  
pp. 149-153 ◽  
Author(s):  
Janet M. Shapiro ◽  
Kathleen L. Pedersen ◽  
Randolph P. Cole
Keyword(s):  
Respiratory Failure ◽  
Gas Exchange ◽  
Bronchoalveolar Lavage ◽  
Pneumocystis Carinii ◽  
Ventilatory Support ◽  
Fiberoptic Bronchoscopy ◽  
Blood Gases ◽  
Diffuse Lung Disease ◽  
Arterial Blood ◽  
Diffuse Lung

The effect of fiberoptic bronchoscopy with bronchoalveolar lavage (BAL) on arterial oxygenation was examined in 22 patients with acute respiratory failure requiring mechanical ventilatory support. Arterial blood gases were determined immediately prior to BAL and at 15, 60, 120, and 360 minutes following BAL. PaO2/FIO2 decreased at 15 minutes and continued to decrease to approximately 33% below the baseline value at 2 hours. PaO2/FIO2 then remained constant over the remainder of the 6-hour study period. No substantial changes in FIO2, level of positive end-expiratory pressure, or intravenous pressor requirements occurred during the period of observation. Patients with lower pre-BAL PaO2/FIO2 ratios showed the least reduction in PaO2/FiO2 following BAL The BAL was diagnostic in 9 of 22 (41%) patients ( Pneumocystis carinii pneumonia in 5, bacterial pneumonitis in 2, and neoplastic involvement of the lung in 2). BAL was associated with mild deterioration of gas exchange but did not require significant changes in ventilatory or hemodynamic support for the 6-hour interval studied.

Control of arrhythmic breathing in bimodal breathers: Amphibia

1988 ◽  
Vol 66 (1) ◽  
pp. 6-19 ◽  
Author(s):  
Robert G. Boutilier
Keyword(s):  
Control System ◽  
Gas Exchange ◽  
Lung Ventilation ◽  
Breath Holding ◽  
Breath Hold ◽  
Breathing Patterns ◽  
Gas Exchanges ◽  
Air Breathing ◽  
Activity State ◽  
Breath Pattern

Amphibians employ a system of gas exchange whereby various combinations of the lungs, gills, and skin are used to exploit gas exchanges in both air and water (bimodal breathing). Continuous lung ventilation is rarely observed in these animals. Instead, the dominant breath pattern is arrhythmic in nature and is believed to have evolved in response to a periodic need to supplement aquatic gas exchange. Such a need is largely dependent on the activity state of the animal concerned and its capacity for aquatic gas exchange. The overall control system appears to be one that turns lung ventilation on and off by trigger signals arising from chemo- and mechano-sensitive receptors responding to changing conditions during periods of breath holding and breathing. In amphibians in which the aquatic exchanger is a major avenue for CO2 elimination, [Formula: see text] levels in the lungs and blood do not change substantially in the latter stages of a breath hold. Under these conditions falling levels of oxygen may be the primary stimulus to terminate the breath hold and initiate breathing. There is, however, some interaction between the two gases since elevated CO2 levels affect the sensitivity of the predominantly O2-mediated response. Another major component in determining air-breathing patterns in these animals is their ability to delay the onset of breathing when certain behavioural activities take precedence over the need for additional gas exchange.

Alveolar gas exchange during breath-hold diving

1963 ◽  
Vol 18 (3) ◽  
pp. 471-477 ◽  
Author(s):  
E. H. Lanphier ◽  
H. Rahn
Keyword(s):  
Gas Exchange ◽  
Sea Water ◽  
Ambient Pressure ◽  
Acute Hypoxia ◽  
Normal Subjects ◽  
The Body ◽  
Breath Holding ◽  
Breath Hold ◽  
October 17 ◽  
Alveolar Gas Exchange

Use of a recompression chamber permitted simulation of breath-hold dives to 33 ft of sea water (2 atm abs). Four normal subjects made such dives during rest and mild exertion while delivering alveolar gas samples at frequent intervals by a partial-rebreathing procedure. The course of alveolar gas exchange differed greatly from that in ordinary breath holding. Oxygen uptake remained at near normal levels until ascent owing to the maintenance of alveolar Po2 by increased ambient pressure. Reversal of CO2 transfer occurred during descent, and little CO2 moved in the normal direction until ascent. Greater uptake of oxygen and retention of CO2 in the body led to lower final values of both alveolar Po2 and Pco2 than in comparable breath holding at the surface. Hyperventilation made possible longer dives with harder work, and in these the Po2 reached very low values on ascent. One subject showed a final Po2 of 24 mm Hg with evidence of reversed O2 transfer. Acute hypoxia on ascent is a likely cause of drowning in breath-hold diving. Submitted on October 17, 1962

scholarly journals SARS-CoV-2 pneumonia succesfully treated with cpap and cycles of tripod position: a case report

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Michela Rauseo ◽  
Lucia Mirabella ◽  
Rosa Roberta Caporusso ◽  
Leonarda Pia Cantatore ◽  
Marco Paolo Perrini ◽  
...  
Keyword(s):  
Respiratory Failure ◽  
Gas Exchange ◽  
Ventilatory Support ◽  
Blood Gases ◽  
Normal Lung ◽  
Prone Positioning ◽  
Arterial Blood Gases ◽  
Hypoxemic Respiratory Failure ◽  
Unsuccessful Attempt ◽  
Arterial Blood

Abstract Background Pneumonia induced by 2019 Coronavirus (COVID-19) is characterized by hypoxemic respiratory failure that may present with a broad spectrum of clinical phenotypes. At the beginning, patients may have normal lung compliance and be responsive to noninvasive ventilatory support, such as CPAP. However, the transition to more severe respiratory failure - Severe Acute Respiratory Syndrome (SARS-CoV-2), necessitating invasive ventilation is often abrupt and characterized by a severe V/Q mismatch that require cycles of prone positioning. The aim of this case is to report the effect on gas exchange, respiratory mechanics and hemodynamics of tripod (or orthopneic sitting position) used as an alternative to prone position in a patient with mild SARS-CoV-2 pneumonia ventilated with helmet CPAP. Case presentation A 77-year-old awake and collaborating male patient with mild SARS-CoV-2 pneumonia and ventilated with Helmet CPAP, showed sudden worsening of gas exchange without dyspnea. After an unsuccessful attempt of prone positioning, we alternated three-hours cycles of semi-recumbent and tripod position, still keeping him in CPAP. Arterial blood gases (PaO2/FiO2, PaO2, SaO2, PaCO2 and A/a gradient), respiratory (VE, VT, RR) and hemodynamic parameters (HR, MAP) were collected in the supine and tripod position. Cycles of tripod position were continued for 3 days. The patient had a clinically important improvement in arterial blood gases and respiratory parameters, with stable hemodynamic and was successfully weaned and discharged to ward 10 days after pneumonia onset. Conclusions Tripod position during Helmet CPAP can be applied safely in patients with mild SARS-CoV-2 pneumonia, with improvement of oxygenation and V/Q matching, thus reducing the need for intubation.

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