scholarly journals Awake prone position reduces work of breathing in patients with COVID-19 ARDS supported by CPAP

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Davide Chiumello ◽  
Elena Chiodaroli ◽  
Silvia Coppola ◽  
Simone Cappio Borlino ◽  
Claudia Granata ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Prone Position ◽  
Supine Position ◽  
Minute Ventilation ◽  
Work Of Breathing ◽  
Invasive Mechanical Ventilation ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Pressure Time ◽  
Pressure Swing

Abstract Background The use of awake prone position concomitant to non-invasive mechanical ventilation in acute respiratory distress syndrome (ARDS) secondary to COVID-19 has shown to improve gas exchange, whereas its effect on the work of breathing remain unclear. The objective of this study was to evaluate the effects of awake prone position during helmet continuous positive airway pressure (CPAP) ventilation on inspiratory effort, gas exchange and comfort of breathing. Methods Forty consecutive patients presenting with ARDS due to COVID-19 were prospectively enrolled. Gas exchange, esophageal pressure swing (ΔPes), dynamic transpulmonary pressure (dTPP), modified pressure time product (mPTP), work of breathing (WOB) and comfort of breathing, were recorded on supine position and after 3 h on prone position. Results The median applied PEEP with helmet CPAP was 10 [8–10] cmH2O. The PaO2/FiO2 was higher in prone compared to supine position (Supine: 166 [136–224] mmHg, Prone: 314 [232–398] mmHg, p < 0.001). Respiratory rate and minute ventilation decreased from supine to prone position from 20 [17–24] to 17 [15–19] b/min (p < 0.001) and from 8.6 [7.3–10.6] to 7.7 [6.6–8.6] L/min (p < 0.001), respectively. Prone position did not reduce ΔPes (Supine: − 7 [− 9 to − 5] cmH2O, Prone: − 6 [− 9 to − 5] cmH2O, p = 0.31) and dTPP (Supine: 17 [14–19] cmH2O, Prone: 16 [14–18] cmH2O, p = 0.34). Conversely, mPTP and WOB decreased from 152 [104–197] to 118 [90–150] cmH2O/min (p < 0.001) and from 146 [120–185] to 114 [95–151] cmH2O L/min (p < 0.001), respectively. Twenty-six (65%) patients experienced a reduction in WOB of more than 10%. The overall sensation of dyspnea was lower in prone position (p = 0.005). Conclusions Awake prone position with helmet CPAP enables a reduction in the work of breathing and an improvement in oxygenation in COVID-19-associated ARDS.

Effect of Synchronized Intermittent Mandatory Ventilation on Respiratory Workload in Infants after Cardiac Surgery

2001 ◽  
Vol 95 (4) ◽  
pp. 881-888 ◽  
Author(s):  
Hideaki Imanaka ◽  
Masaji Nishimura ◽  
Hiroshi Miyano ◽  
Hideki Uemura ◽  
Toshikatsu Yagihara
Keyword(s):  
Cardiac Surgery ◽  
Tidal Volume ◽  
Minute Ventilation ◽  
Work Of Breathing ◽  
Esophageal Pressure ◽  
Intermittent Mandatory Ventilation ◽  
Negative Deflection ◽  
Arterial Blood ◽  
Pressure Time ◽  
Post Cardiac Surgery

Background Synchronized intermittent mandatory ventilation (SIMV) is commonly used in infants and adults. However, few investigations have examined how SIMV reduces respiratory workload in infants. The authors evaluated how infants' changing respiratory patterns when reducing SIMV rate increased respiratory load. The authors also investigated whether SIMV reduces infant respiratory workload in proportion to the rate of mandatory breaths and which rate of SIMV provides respiratory workloads similar to those after tracheal extubation. Methods When 11 post-cardiac surgery infants aged 2-11 months were to be weaned with SIMV, the authors randomly applied five levels of mandatory breathing: 0, 5, 10, 15, and 20 breaths/min. All patients underwent ventilation with SIMV mode: pressure control ventilation, 16 cm H2O; inspiratory time, 0.8 s; triggering sensitivity, 0.6 l/min; and positive endexpiratory pressure, 3 cm H2O. After establishing steady-state conditions at each SIMV rate, arterial blood gases were analyzed, and esophageal pressure, airway pressure, and airflow were measured. Inspiratory work of breathing, pressure-time products, and the negative deflection of esophageal pressure were calculated separately for assisted breaths, for spontaneous breaths, and for total breaths per minute. Measurements were repeated after extubation. Results As the SIMV rate decreased, although minute ventilation and arterial carbon dioxide tension were maintained at constant values, spontaneous breathing rate and tidal volume increased. Work of breathing, pressure-time products, and negative deflection of esophageal pressure increased as the SIMV rate decreased. Work of breathing and pressure-time products after extubation were intermediate between those at a SIMV rate of 5 breaths/min and those at 0 breaths/min. Conclusion When the load to breathing was increased progressively by decreasing the SIMV rate in post-cardiac surgery infants, tidal volume and spontaneous respiratory rate both increased. In addition, work of breathing and pressure-time products were increased depending on the SIMV rate.

Mechanics of the respiratory system and breathing pattern during sleep in normal humans

1984 ◽  
Vol 56 (1) ◽  
pp. 133-137 ◽  
Author(s):  
D. W. Hudgel ◽  
R. J. Martin ◽  
B. Johnson ◽  
P. Hill
Keyword(s):  
Eye Movement ◽  
Rem Sleep ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Transpulmonary Pressure ◽  
Dynamic Compliance ◽  
Face Mask ◽  
Esophageal Pressure ◽  
Rapid Eye Movement ◽  
Airflow Resistance

The purposes of this investigation were to describe the changes in 1) dynamic compliance of the lungs, 2) airflow resistance, and 3) breathing pattern that occur during sleep in normal adult humans. Six subjects wore a tightly fitting face mask. Flow and volume were obtained from a pneumotachograph attached to the face mask. Transpulmonary pressure was calculated as the difference between esophageal pressure obtained with a balloon and mask pressure. At least 20 consecutive breaths were analyzed for dynamic compliance, airflow resistance, and breathing pattern during wakefulness, non-rapid-eye-movement stage 2 and rapid-eye-movement (REM) sleep. Dynamic compliance did not change significantly. Airflow resistance increased during sleep; resistance was 3.93 +/- 0.56 cmH2O X 1–1 X s during wakefulness, 7.96 +/- 0.95 in stage 2 sleep, and 8.66 +/- 1.43 in REM sleep (P less than 0.02). By placing a catheter in the retroepiglottic space and thus dividing the airway into upper and lower zones, we found the increase in resistance occurred almost entirely above the larynx. Decreases in tidal volume, minute ventilation, and mean inspiratory flow observed during sleep were not statistically significant.

The Effect of Posture on Ventilation and Lung Mechanics in Preterm and Light-for-Date Infants

PEDIATRICS ◽  
1979 ◽  
Vol 64 (4) ◽  
pp. 429-432 ◽  
Author(s):  
Alastair A. Hutchison ◽  
Keith R. Ross ◽  
George Russell
Keyword(s):  
Tidal Volume ◽  
Prone Position ◽  
Supine Position ◽  
Work Of Breathing ◽  
Newborn Infants ◽  
Lateral Position ◽  
Minute Volume ◽  
Lung Mechanics ◽  
Total Work ◽  
Preterm Group

The effect of right lateral, supine, and prone postures on ventilation and lung mechanics was studied in 23 healthy newborn infants, ten preterm and 13 term, "light-for-date." In the preterm group, tidal volume, minute volume, elastic work, inspiratory viscous work, total viscous work, and the total work of breathing were significantly greater in the prone position than in the supine position. Results obtained in the lateral position did not differ significantly from those in the prone or supine positions. Posture did not significantly affect tidal volume or lung mechanics in the light-for-date infants. The prone position is suggested to be the optimum nursing posture for healthy preterm infants.

Effect of the chest wall and blood volume on pulmonary distensibility

1992 ◽  
Vol 72 (1) ◽  
pp. 186-193 ◽  
Author(s):  
H. J. Colebatch ◽  
C. K. Ng ◽  
N. Berend ◽  
F. J. Maccioni
Keyword(s):  
Chest Wall ◽  
Blood Volume ◽  
Surface Pressure ◽  
Supine Position ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Relative Increase ◽  
Alveolar Volume ◽  
Pulmonary Blood Volume ◽  
Gas Volume

To determine the reason for increased pulmonary distensibility in excised lungs, we performed deflation pressure-volume (PV) studies in 24 dogs. Exponential analysis of PV data gave K, an index of distensibility. Lung volume was measured by dilution of neon. Compared with measurements obtained in the supine position, with the chest closed, and with esophageal pressure (Pes) to obtain transpulmonary pressure, K was not changed significantly with the chest strapped, with pleural pressure to obtain transpulmonary pressure, or with the chest open. From displacement of PV curves obtained in the supine position and with the chest closed or open, we estimated that Pes was 0.18 kPa greater than average lung surface pressure. An increase in K in the prone and head-up positions was attributed to a traction artifact decreasing Pes. Exsanguination increased K and produced a relative increase in gas volume. These results show that overall pulmonary distensibility is unaffected by an intact chest wall. An increase in K and gas volume after exsanguination probably reflects a decreased pulmonary blood volume, with collapse of capillaries increasing the alveolar volume-to-surface ratio.

Effect of body posture on lung volumes

1961 ◽  
Vol 16 (1) ◽  
pp. 27-29 ◽  
Author(s):  
Francisco Moreno ◽  
Harold A. Lyons
Keyword(s):  
Tidal Volume ◽  
Prone Position ◽  
Supine Position ◽  
Total Lung Capacity ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Body Posture ◽  
Mean Values ◽  
Lung Capacity ◽  
Residual Capacity

The changes produced by body posture on total lung capacity and its subdivisions have been reported for all positions except the prone position. Twenty normal subjects, twelve males and eight females, had determinations of total lung capacity in the three body positions, sitting, supine and prone. Tidal volume, minute ventilation and O2 consumption were also measured. The changes found on assumption of the supine position from the sitting position were similar to those previously reported. For the prone position, a smaller inspiratory capacity and a larger expiratory reserve volume were found. The mean values were changed, respectively, –8% and +37%. Associated with these changes was a significant increase of the functional residual capacity by 636 ml. Ventilation did not change significantly from that found during sitting, unlike the findings associated with the supine position, in which position the tidal volume was decreased. Respiratory frequency remained the same for all positions. Submitted on April 5, 1960

Effects of high-frequency breathing on pulmonary ventilation and gas exchange

1983 ◽  
Vol 55 (6) ◽  
pp. 1854-1861 ◽  
Author(s):  
C. Frostell ◽  
J. N. Pande ◽  
G. Hedenstierna
Keyword(s):  
Gas Exchange ◽  
Dead Space ◽  
High Frequency ◽  
Gas Flow ◽  
Minute Ventilation ◽  
Pulmonary Ventilation ◽  
Balloon Catheter ◽  
Transpulmonary Pressure ◽  
Arterial Oxygen ◽  
Respiratory Inductive Plethysmography

The effects of spontaneous high-frequency breathing (HFB) on lung function were evaluated in three subjects highly trained in the practice of yoga. Transpulmonary pressure was measured by an esophageal balloon catheter and gas flow by pneumotachography. The abdominal and rib cage contributions to tidal breathing were measured separately by respiratory inductive plethysmography. Gas exchange was studied by the conventional technique and by multiple inert gas elimination. During HFB, respiratory rate increased to 232 cycles/min with a tidal volume of 0.35 liter. This resulted in a more than 10-fold increase in expired minute ventilation to approximately 90 1/min. The transpulmonary pressure varied by 20 cmH2O, with the calculated elastic, resistive, and accelerative components varying by 2, 20, and 8 cmH2O, respectively. Respiratory work increased more than 200-fold in comparison with resting ventilation. A phase shift between thoracic and abdominal breathing was observed and was interpreted as a volume displacement of approximately 30 1/min between the two parts of the respiratory system. Arterial oxygen and carbon dioxide tension remained normal. Bohr dead space increased, while acetone dead space remained unaltered. A bimodal distribution of ventilation-perfusion ratios (VA/Q) was observed, with one mode in normal and another in “high” VA/Q regions.

scholarly journals Mechanisms of Orthopnoea in Patients with Advanced COPD

2020 ◽  
pp. 2000754
Author(s):  
Amany F. Elbehairy ◽  
Azmy Faisal ◽  
Hannah McIsaac ◽  
Nicolle J. Domnik ◽  
Kathryn M. Milne ◽  
...  
Keyword(s):  
Supine Position ◽  
Minute Ventilation ◽  
Pulmonary Function Tests ◽  
Work Of Breathing ◽  
Airflow Obstruction ◽  
Lung Compliance ◽  
Chronic Obstructive ◽  
Inspiratory Muscles ◽  
Elastic Loading ◽  
Dynamic Lung Compliance

Many patients with severe chronic obstructive pulmonary disease (COPD) report unpleasant respiratory sensation at rest, further amplified by adoption of supine position (orthopnoea). The mechanisms of this acute symptomatic deterioration are poorly understood.16 patients with advanced COPD and history of orthopnoea and 16 age- and sex-matched healthy controls (CTRL) underwent pulmonary function tests and detailed sensory-mechanical measurements including inspiratory neural drive (IND, diaphragm electromyography), oesophageal and gastric pressures in sitting and supine positions.Patients had severe airflow obstruction (FEV1: 40±18%predicted) and lung hyperinflation. Regardless of the position, patients had lower inspiratory capacity (IC) and higher IND for a given tidal volume (i.e. greater neuromechanical dissociation (NMD)), higher intensity of breathing discomfort, minute ventilation (⩒E) and breathing frequency (Fb) compared with CTRL (all p<0.05). In supine position in CTRL (versus sitting erect): IC increased (by 0.48L) with a small drop in ⩒E mainly due to reduced Fb (all p<0.05). By contrast, patients’ IC remained unaltered, but dynamic lung compliance decreased (p<0.05) in the supine position. Breathing discomfort, inspiratory work of breathing, inspiratory effort, IND, NMD and neuro-ventilatory uncoupling all increased in COPD in the supine position (p<0.05), but not in CTRL. Orthopnoea was associated with acute changes in IND (r=0.65, p=0.01), neuro-ventilatory uncoupling (r=0.76, p=0.001) and NMD (r=0.73, p=0.002).In COPD, onset of orthopnoea coincided with an abrupt increase in elastic loading of the inspiratory muscles in recumbency in association with increased IND and greater neuromechanical dissociation of the respiratory system.

scholarly journals Feasibility, tolerance and effectiveness of enteral feeding in critically ill patients in prone position

2020 ◽  
pp. 175114371990010 ◽  
Author(s):  
Raymond Dominic Savio ◽  
Rajalakshmi Parasuraman ◽  
Daphnee Lovesly ◽  
Bhuvaneshwari Shankar ◽  
Lakshmi Ranganathan ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Enteral Nutrition ◽  
Critically Ill ◽  
Prone Position ◽  
Supine Position ◽  
Critically Ill Patients ◽  
Invasive Mechanical Ventilation ◽  
Apache Ii ◽  
Apache Ii Score ◽  
The Mean

Aim To assess the feasibility, tolerance and effectiveness of enteral nutrition in critically ill patients receiving invasive mechanical ventilation in the prone position for severe Acute Respiratory Distress Syndrome (ARDS). Methods Prospective observational study conducted in a multidisciplinary critical care unit of a tertiary care hospital from January 2013 until July 2015. All patients with ARDS who received invasive mechanical ventilation in prone position during the study period were included. Patients’ demographics, severity of illness (Acute Physiology and Chronic Health Evaluation (APACHE II) score), baseline markers of nutritional status (subjective global assessment (SGA) and body mass index), details of nutrition delivery during prone and supine hours and outcomes (Length of stay and discharge status) were recorded. Results Fifty-one patients met inclusion criteria out of whom four patients were excluded from analysis since they did not receive any enteral nutrition due to severe hemodynamic instability. The mean age of patients was 46.4 ± 12.9 years, with male:female ratio of 7:3. On admission, SGA revealed moderate malnutrition in 51% of patients and the mean APACHE II score was 26.8 ± 9.2. The average duration of prone ventilation per patient was 60.2 ± 30.7 h. All patients received continuous nasogastric/orogastric feeds. The mean calories (kcal/kg/day) and protein (g/kg/day) prescribed in the supine position were 24.5 ± 3.8 and 1.1 ± 0.2 while the mean calories and protein prescribed in prone position were 23.5 ± 3.6 and 1.1 ± 0.2, respectively. Percentage of prescribed calories received by patients in supine position was similar to that in prone position (83.2% vs. 79.6%; P = 0.12). Patients received a higher percentage of prescribed protein in supine compared to prone position (80.8% vs. 75%, P = 0.02). The proportion of patients who received at least 75% of the caloric and protein goals was 37 (78.7%) and 37 (78.7%) in supine and 32 (68.1%) and 21 (44.6%) in prone position. Conclusion In critically ill patients receiving invasive mechanical ventilation in the prone position, enteral nutrition with nasogastric/orogastric feeding is feasible and well tolerated. Nutritional delivery of calories and proteins in prone position is comparable to that in supine position.

Measurement of Pressure–Time Product during Spontaneous Assisted Breathing by Rapid Interrupter Technique

2007 ◽  
Vol 106 (3) ◽  
pp. 484-490 ◽  
Author(s):  
Giacomo Bellani ◽  
Nicolò Patroniti ◽  
Dieter Weismann ◽  
Lucia Galbiati ◽  
Francesco Curto ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Pressure Support ◽  
Work Of Breathing ◽  
Ventilatory Support ◽  
Respiratory Muscles ◽  
Esophageal Pressure ◽  
Assisted Ventilation ◽  
Reliable Estimate ◽  
Pressure Time ◽  
Pressure Time Product

Background Measuring the work of breathing of patients undergoing spontaneous assisted ventilation can be useful to monitor and titrate ventilatory support. The aim of this study was to obtain measurements of the pressure generated by the respiratory muscles (PMUSC) and the derived pressure-time product (PTP; a good indicator of the metabolic work of breathing), performing the rapid interrupter technique with a commercial ventilator. Methods A Draeger Evita 4 ventilator (Draeger Medical, Lubeck, Germany) was controlled by a personal computer to rapidly interrupt the airway flow at different times and volumes of the respiratory cycle during pressure-support ventilation. From the airway pressure tracing after the occlusion, the authors estimated the alveolar pressure and PMUSC; the integration of PMUSC values over the inspiratory time yields the measurement of PTP. Esophageal pressure measurements were used as a reference. After a bench study of the valves' performance, the authors performed 11 measurement sequences in eight patients. Results The closure times for the inspiratory and expiratory valves were 74 +/- 10 and 61 +/- 13 ms, respectively. The interrupter technique provided a reliable estimate of PMUSC (PMUSC, occl = 1.00 . PMUSC, pes + 0.19; r = 0.88; 95% confidence interval for agreement, +5.49/-5.32 cm H2O). PTPoccl tightly correlated with PTPpes (PTPoccl = 0.95 . PTPpes + 0.13; r = 0.96; 95% confidence interval, 1.94/-1.61 cm H2O . s). Conclusion The rapid interrupter technique can be performed by means of a commercial ventilator, providing reliable measurement of PMUSC and PTP.

scholarly journals Gas exchange and ventilation–perfusion relationships in the lung

2014 ◽  
Vol 44 (4) ◽  
pp. 1023-1041 ◽  
Author(s):  
Johan Petersson ◽  
Robb W. Glenny
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Gas Exchange ◽  
Minute Ventilation ◽  
Work Of Breathing ◽  
Arterial Oxygen Tension ◽  
Supplemental Oxygen ◽  
Arterial Oxygen ◽  
Respiratory Drive ◽  
Clinical Scenarios

This review provides an overview of the relationship between ventilation/perfusion ratios and gas exchange in the lung, emphasising basic concepts and relating them to clinical scenarios. For each gas exchanging unit, the alveolar and effluent blood partial pressures of oxygen and carbon dioxide (PO2andPCO2) are determined by the ratio of alveolar ventilation to blood flow (V′A/Q′) for each unit. Shunt and lowV′A/Q′ regions are two examples ofV′A/Q′ mismatch and are the most frequent causes of hypoxaemia. Diffusion limitation, hypoventilation and low inspiredPO2cause hypoxaemia, even in the absence ofV′A/Q′ mismatch. In contrast to other causes, hypoxaemia due to shunt responds poorly to supplemental oxygen. Gas exchanging units with little or no blood flow (highV′A/Q′ regions) result in alveolar dead space and increased wasted ventilation,i.e.less efficient carbon dioxide removal. Because of the respiratory drive to maintain a normal arterialPCO2, the most frequent result of wasted ventilation is increased minute ventilation and work of breathing, not hypercapnia. Calculations of alveolar–arterial oxygen tension difference, venous admixture and wasted ventilation provide quantitative estimates of the effect ofV′A/Q′ mismatch on gas exchange. The types ofV′A/Q′ mismatch causing impaired gas exchange vary characteristically with different lung diseases.

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