Efficacy of a heated passover humidifier during noninvasive ventilation: A bench study

Anne E Holland, Linda Denehy, Catherine Buchan, John W Wilson

Research output: Contribution to journalArticleResearchpeer-review

32 Citations (Scopus)

Abstract

BACKGROUND: Noninvasive positive-pressure ventilation (NPPV) delivers air at a high flow, which is associated with airway mucosal drying and impaired airway functioning. OBJECTIVES: To examine the effects of mechanical ventilation parameters on relative humidity and absolute humidity during NPPV, and to evaluate the effect of a heated passover humidifier on relative humidity, absolute humidity, and ventilator performance during NPPV. METHODS: We performed a bench study to assess the effects of inspiratory positive airway pressure (EPAP) of 10 cm H2O, 15 cm H2O, and 20 cm H2O, respiratory rates of 12 breaths/min and 24 breaths/min, and inspiratory-expiratory ratios of 1:2 and 1:3 on relative and absolute humidity. The measurements were obtained on room air and with a heated humidifier at medium and maximum heater settings. RESULTS: Without humidification, the relative humidity in the NPPV circuit (range 16.3-26.5 ) was substantially lower than the ambient relative humidity (27.6-31.5 ) at all ventilatory settings. Increasing the IPAP decreased the relative humidity (Spearman s rho=0.67, p <0.001). Changing the respiratory rate or inspiratory-expiratory ratio had no significant effect. Both relative and absolute humidity increased with humidification, and the air was fully saturated at the maximum heater setting. Delivered IPAP was reduced by 0.5-1 cm H2O during humidification. CONCLUSIONS: NPPV delivers air with a low relative humidity, especially with high inspiratory pressure. Addition of a heated humidifier increases the relative and absolute humidity to levels acceptable for nonintubated patients, with minimal effect on delivered pressure. Consideration should be given to heated humidification during NPPV, especially when airway drying and secretion retention are of concern.
Original languageEnglish
Pages (from-to)38 - 44
Number of pages7
JournalRespiratory care
Volume52
Issue number1
Publication statusPublished - 2007

Cite this

@article{db0510330305423a9484702f48c67b53,
title = "Efficacy of a heated passover humidifier during noninvasive ventilation: A bench study",
abstract = "BACKGROUND: Noninvasive positive-pressure ventilation (NPPV) delivers air at a high flow, which is associated with airway mucosal drying and impaired airway functioning. OBJECTIVES: To examine the effects of mechanical ventilation parameters on relative humidity and absolute humidity during NPPV, and to evaluate the effect of a heated passover humidifier on relative humidity, absolute humidity, and ventilator performance during NPPV. METHODS: We performed a bench study to assess the effects of inspiratory positive airway pressure (EPAP) of 10 cm H2O, 15 cm H2O, and 20 cm H2O, respiratory rates of 12 breaths/min and 24 breaths/min, and inspiratory-expiratory ratios of 1:2 and 1:3 on relative and absolute humidity. The measurements were obtained on room air and with a heated humidifier at medium and maximum heater settings. RESULTS: Without humidification, the relative humidity in the NPPV circuit (range 16.3-26.5 ) was substantially lower than the ambient relative humidity (27.6-31.5 ) at all ventilatory settings. Increasing the IPAP decreased the relative humidity (Spearman s rho=0.67, p <0.001). Changing the respiratory rate or inspiratory-expiratory ratio had no significant effect. Both relative and absolute humidity increased with humidification, and the air was fully saturated at the maximum heater setting. Delivered IPAP was reduced by 0.5-1 cm H2O during humidification. CONCLUSIONS: NPPV delivers air with a low relative humidity, especially with high inspiratory pressure. Addition of a heated humidifier increases the relative and absolute humidity to levels acceptable for nonintubated patients, with minimal effect on delivered pressure. Consideration should be given to heated humidification during NPPV, especially when airway drying and secretion retention are of concern.",
author = "Holland, {Anne E} and Linda Denehy and Catherine Buchan and Wilson, {John W}",
year = "2007",
language = "English",
volume = "52",
pages = "38 -- 44",
journal = "Respiratory care",
issn = "0020-1324",
number = "1",

}

Efficacy of a heated passover humidifier during noninvasive ventilation: A bench study. / Holland, Anne E; Denehy, Linda; Buchan, Catherine; Wilson, John W.

In: Respiratory care, Vol. 52, No. 1, 2007, p. 38 - 44.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Efficacy of a heated passover humidifier during noninvasive ventilation: A bench study

AU - Holland, Anne E

AU - Denehy, Linda

AU - Buchan, Catherine

AU - Wilson, John W

PY - 2007

Y1 - 2007

N2 - BACKGROUND: Noninvasive positive-pressure ventilation (NPPV) delivers air at a high flow, which is associated with airway mucosal drying and impaired airway functioning. OBJECTIVES: To examine the effects of mechanical ventilation parameters on relative humidity and absolute humidity during NPPV, and to evaluate the effect of a heated passover humidifier on relative humidity, absolute humidity, and ventilator performance during NPPV. METHODS: We performed a bench study to assess the effects of inspiratory positive airway pressure (EPAP) of 10 cm H2O, 15 cm H2O, and 20 cm H2O, respiratory rates of 12 breaths/min and 24 breaths/min, and inspiratory-expiratory ratios of 1:2 and 1:3 on relative and absolute humidity. The measurements were obtained on room air and with a heated humidifier at medium and maximum heater settings. RESULTS: Without humidification, the relative humidity in the NPPV circuit (range 16.3-26.5 ) was substantially lower than the ambient relative humidity (27.6-31.5 ) at all ventilatory settings. Increasing the IPAP decreased the relative humidity (Spearman s rho=0.67, p <0.001). Changing the respiratory rate or inspiratory-expiratory ratio had no significant effect. Both relative and absolute humidity increased with humidification, and the air was fully saturated at the maximum heater setting. Delivered IPAP was reduced by 0.5-1 cm H2O during humidification. CONCLUSIONS: NPPV delivers air with a low relative humidity, especially with high inspiratory pressure. Addition of a heated humidifier increases the relative and absolute humidity to levels acceptable for nonintubated patients, with minimal effect on delivered pressure. Consideration should be given to heated humidification during NPPV, especially when airway drying and secretion retention are of concern.

AB - BACKGROUND: Noninvasive positive-pressure ventilation (NPPV) delivers air at a high flow, which is associated with airway mucosal drying and impaired airway functioning. OBJECTIVES: To examine the effects of mechanical ventilation parameters on relative humidity and absolute humidity during NPPV, and to evaluate the effect of a heated passover humidifier on relative humidity, absolute humidity, and ventilator performance during NPPV. METHODS: We performed a bench study to assess the effects of inspiratory positive airway pressure (EPAP) of 10 cm H2O, 15 cm H2O, and 20 cm H2O, respiratory rates of 12 breaths/min and 24 breaths/min, and inspiratory-expiratory ratios of 1:2 and 1:3 on relative and absolute humidity. The measurements were obtained on room air and with a heated humidifier at medium and maximum heater settings. RESULTS: Without humidification, the relative humidity in the NPPV circuit (range 16.3-26.5 ) was substantially lower than the ambient relative humidity (27.6-31.5 ) at all ventilatory settings. Increasing the IPAP decreased the relative humidity (Spearman s rho=0.67, p <0.001). Changing the respiratory rate or inspiratory-expiratory ratio had no significant effect. Both relative and absolute humidity increased with humidification, and the air was fully saturated at the maximum heater setting. Delivered IPAP was reduced by 0.5-1 cm H2O during humidification. CONCLUSIONS: NPPV delivers air with a low relative humidity, especially with high inspiratory pressure. Addition of a heated humidifier increases the relative and absolute humidity to levels acceptable for nonintubated patients, with minimal effect on delivered pressure. Consideration should be given to heated humidification during NPPV, especially when airway drying and secretion retention are of concern.

UR - http://www.rcjournal.com/contents/01.07/01.07.0038.pdf

M3 - Article

VL - 52

SP - 38

EP - 44

JO - Respiratory care

JF - Respiratory care

SN - 0020-1324

IS - 1

ER -