Pressure-Time Product during Continuous Positive Airway Pressure, Pressure Support Ventilation, and T-Piece during Weaning from Mechanical Ventilation

Sassoon, Catherine S. H.; Light, Richard W.; Lodia, R.; Sieck, Gary C.; Mahutte, C. K.

doi:10.1164/ajrccm/143.3.469

Cited by 203 publications

(122 citation statements)

References 12 publications

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“…This area was referred to as the chest-wall static recoil pressure-time curve relationship. 24 A difference between the beginning of the negative esophageal-pressure deflection and the zero-flow point was taken as the intrinsic PEEP 25 and was corrected for any abdominal pressure activity. 26 We computed patient inspiratory WOB per breath from the area included between the esophageal pressure/tidal volume loop and the chest-wall relaxation curve, using the Campbell diagram, as previously described.…”

Section: Bronchodilator Delivery With Versus Without Cpapmentioning

confidence: 99%

Aerosol Delivery and Humidification With the Boussignac Continuous Positive Airway Pressure Device

et al. 2011

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BACKGROUND: A simple method for effective bronchodilator aerosol delivery while administering continuing continuous positive airway pressure (CPAP) would be useful in patients with severe bronchial obstruction. OBJECTIVE: To assess the effectiveness of bronchodilator aerosol delivery during CPAP generated by the Boussignac CPAP system and its optimal humidification system. METHODS: First we assessed the relationship between flow and pressure generated in the mask with the Boussignac CPAP system. Next we measured the inspired-gas humidity during CPAP, with several humidification strategies, in 9 healthy volunteers. We then measured the bronchodilator aerosol particle size during CPAP, with and without heat-and-moisture exchanger, in a bench study. Finally, in 7 patients with acute respiratory failure and airway obstruction, we measured work of breathing and gas exchange after a ␤ 2 -agonist bronchodilator aerosol (terbutaline) delivered during CPAP or via standard nebulization. RESULTS: Optimal humidity was obtained only with the heat-and-moisture exchanger or heated humidifier. The heat-and-moisture exchanger had no influence on bronchodilator aerosol particle size. Work of breathing decreased similarly after bronchodilator via either standard nebulization or CPAP, but P aO 2 increased significantly only after CPAP aerosol delivery. CONCLUSIONS: CPAP bronchodilator delivery decreases the work of breathing as effectively as does standard nebulization, but produces a greater oxygenation improvement in patients with airway obstruction. To optimize airway humidification, a heat-and-moisture exchanger could be used with the Boussignac CPAP system, without modifying aerosol delivery.

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Section: Bronchodilator Delivery With Versus Without Cpapmentioning

confidence: 99%

Aerosol Delivery and Humidification With the Boussignac Continuous Positive Airway Pressure Device

et al. 2011

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“…This is usually extrapolated from the Pwst/ volume curve of normal subjects, making the assumption that these relationships are linear within the tidal volume range [17]. The area measured for PTPoes compared to the area subtended by Poes and the Pwst/time curve during inpiration are only slightly different.…”

Section: Pressure/time Product Analysismentioning

confidence: 99%

Respiratory muscle activity in patients with COPD walking to exhaustion with and without pressure support

Kyroussis¹,

Polkey²,

Hamnegärd³

et al. 2000

Eur Respir J

115

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The function of the diaphragm and other respiratory muscles during exercise in chronic obstructive pulmonary disease (COPD) remains controversial and few data exist regarding respiratory muscle pressure generation in this situation.The inspiratory pressure/time products of the oesophageal and transdiaphragmatic pressure, and the expiratory gastric pressure/time product during exhaustive treadmill walking in 12 patients with severe COPD are reported. The effect of noninvasive positive pressure ventilation during treadmill exercise was also examined in a subgroup of patients (n=6).During free walking, the inspiratory pressure/time products rose early in the walk and then remained level until the patients were forced to stop because of intolerable dyspnoea. In contrast, the expiratory gastric pressure/time product increased progressively throughout the walk. When patients walked the same distance assisted by noninvasive positive pressure ventilation, a substantial reduction was observed in the inspiratory and expiratory pressure/time products throughout the walk. When patients walked with positive pressure ventilation for as long as they could, the pressure/time products observed at exercise cessation were lower than those observed during exercise cessation after free walking.It is concluded that, in severe chronic obstructive pulmonary disease, inspiratory muscle pressure generation does not increase to meet the demands imposed by exhaustive exercise, whereas expiratory muscle pressure generation rises progressively. Inspiratory pressure support was shown to substantially unload all components of the respiratory muscle pump. Eur Respir J 2000; 15: 649±655.

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“…26 The accuracy of the breathing pattern drops when it is assessed during spontaneous breathing trials on CPAP, with or without low-level pressure support, or when it is used to predict the outcome of a patient who tolerated a spontaneous breathing trial. 20,27,28 Our data suggest that the respondents ignored these facts and relied on the breathing pattern obtained on CPAP with low-level pressure support during a successful spontaneous breathing trial.…”

Section: Discussionmentioning

confidence: 86%

Accuracy and Reliability of Extubation Decisions by Intensivists

Tulaimat

Mokhlesi

2011

Respir Care

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BACKGROUND: Mortality increases when extubations fail. Although predictors of extubation failure have been evaluated, physicians' reasoning to extubate a patient has received minimal attention. We hypothesized that the accuracy and reliability of physicians' extubation decisions are low. METHODS: We sent surveys to 55 physicians in the divisions of pulmonary and critical care medicine of 3 teaching hospitals in Chicago, Illinois. The survey comprised 32 clinical vignettes of real patients who were extubated after they tolerated a spontaneous breathing trial (16 failed extubations). Unaware of the outcomes of extubation, the physicians were asked if they would extubate each patient, and to give reasons if they opted not to. We quantified the agreement between and accuracy of the physicians' decisions, determined the patient characteristics that influence the extubation decision, and described the tradeoffs leading to that decision. RESULTS: Completed surveys were obtained from 45 physicians (82%). The physicians postponed extubation in 37% of the cases. Agreement between any 2 physicians was fair (mean ؎ SD phi 0.34 ؎ 0.15) and was highest between attending physicians from the same institution (0.37 ؎ 0.15). In deciding to extubate a patient, 33% of the physicians relied on the breathing pattern on pressure support ventilation, 49% relied on the acid-base status, 13% relied on the mental status, and 8% relied on the amount of secretions. The accuracy of the physicians' extubation decisions was low (area under the receiver operating characteristic curve 0.35). The sensitivity of the physicians identifying the patients who were successfully extubated was 57%, and the specificity was 31%. A model that comprises the same variables that influenced the physicians was more accurate in predicting extubation outcome (area under the receiver operating characteristic curve 0.88). CONCLUSIONS: For a decision made on an almost daily basis in intensive care units, physicians' extubation decisions are inaccurate and only fairly reliable.

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Pressure-Time Product during Continuous Positive Airway Pressure, Pressure Support Ventilation, and T-Piece during Weaning from Mechanical Ventilation

Cited by 203 publications

References 12 publications

Aerosol Delivery and Humidification With the Boussignac Continuous Positive Airway Pressure Device

Aerosol Delivery and Humidification With the Boussignac Continuous Positive Airway Pressure Device

Respiratory muscle activity in patients with COPD walking to exhaustion with and without pressure support

Accuracy and Reliability of Extubation Decisions by Intensivists

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