+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Proportional assist ventilation in acute respiratory failure: effects on breathing pattern and inspiratory effort



Proportional assist ventilation in acute respiratory failure: effects on breathing pattern and inspiratory effort



American Journal of Respiratory and Critical Care Medicine 154(5): 1330-1338



Proportional assist ventilation (PAV) is a new mode of assisted ventilation which, by applying pressure in proportion to volume (volume assist, VA) and flow (flow assist, FA), should specifically reduce the inspiratory effort needed to overcome respiratory system elastance (Ers) and resistance (Rrs), respectively. The aims of this study were to determine (1) the effects of varying the level of VA on breathing pattern, inspiratory effort, and work of breathing, and (2) the interaction between VA and FA. In eight intubated patients with acute respiratory failure, four levels of VA (20 to 80% Ers) with and without a fixed amount of FA (approximately 50% Rrs) were evaluated. Compared with spontaneous breathing, VA increased tidal volume (VT) while respiratory rate (RR) was unchanged or fell slightly. The increase in minute ventilation (VE) was small and not significant. The addition of FA further increased VT while RR was significantly reduced so that VE remained unchanged. Increasing VA produced a graded reduction in inspiratory effort, reflected by decreases in the pressure-time integral of the diaphragm and the inspiratory muscles. These were further reduced when FA was added. VA decreased the elastic work of breathing (Wel) whereas resistive work (Wres) tended to increase so that the fall in total work (W/tot) was less than expected. At each VA setting, the addition of FA significantly reduced Wres and, as a result, Wtot. These results demonstrate that PAV can improve breathing pattern while reducing inspiratory effort by specifically decreasing Wel and Wres, and that VA and FA should be used together to optimize reductions in Wtot and the efficacy of assistance provided.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 009260817

Download citation: RISBibTeXText

PMID: 8912744

DOI: 10.1164/ajrccm.154.5.8912744


Related references

Proportional assist ventilation improves breathing pattern and inspiratory effort in acute respiratory failure. Acta Anaesthesiologica Scandinavica 40(Suppl. 109): 254, 1996

Effects of proportional assist ventilation on inspiratory muscle effort in patients with chronic obstructive pulmonary disease and acute respiratory failure. Anesthesiology 86(1): 79-91, 1997

Effect of Different Levels of Pressure Support and Proportional Assist Ventilation on Breathing Pattern, Work of Breathing and Gas Exchange in Mechanically Ventilated Hypercapnic Copd Patients with Acute Respiratory Failure. Respiration 70(4): 355-361, 2003

Effect of different levels of pressure support and proportional assist ventilation on breathing pattern, work of breathing and gas exchange in mechanically ventilated hypercapnic COPD patients with acute respiratory failure. Respiration; International Review of Thoracic Diseases 70(4): 355-361, 2003

Influences of Duration of Inspiratory Effort, Respiratory Mechanics, and Ventilator Type on Asynchrony With Pressure Support and Proportional Assist Ventilation. Respiratory Care 62(5): 550-557, 2017

Proportional assist versus pressure support ventilation: effects on breathing pattern and respiratory work of patients with chronic obstructive pulmonary disease. Intensive Care Medicine 25(8): 790-798, 1999

Respiratory comfort and breathing pattern during volume proportional assist ventilation and pressure support ventilation: a study on volunteers with artificially reduced compliance. Critical Care Medicine 28(6): 1940-1946, 2000

Effects of partial liquid ventilation on ventilation, respiratory drive, gas exchange, heart rate and arterial blood pressure in spontaneously breathing animals supported with proportional assist ventilation. Pediatric Research 43(4 Part 2): 285A, 1998

Physiologic effects of early administered mask proportional assist ventilation in patients with chronic obstructive pulmonary disease and acute respiratory failure. Critical Care Medicine 28(6): 1791-1797, 2000

The effects of volume- and flow-proportional assist ventilation on the pattern of spontaneous breathing, diaphragmatic EMG, FRC, and blood pressure in rabbits. Pediatric Research 37(4 Part 2): 349A, 1994

Data on respiratory variables in critically ill patients with acute respiratory failure placed on proportional assist ventilation with load adjustable gain factors (PAV+). Data in Brief 8: 484-493, 2016

Noninvasive pressure support versus proportional assist ventilation in acute respiratory failure. Intensive Care Medicine 29(7): 1126-1133, 2003

Proportional assist ventilation in low birth weight infants with acute respiratory disease: A comparison to assist/control and conventional mechanical ventilation. Journal of Pediatrics 135(3): 339-344, 1999

Noninvasive proportional assist ventilation compared with noninvasive pressure support ventilation in hypercapnic acute respiratory failure. Critical Care Medicine 30(2): 323-329, 2002

Effects of Extracorporeal CO2 Removal on Inspiratory Effort and Respiratory Pattern in Patients Who Fail Weaning from Mechanical Ventilation. American Journal of Respiratory and Critical Care Medicine 192(11): 1392-1394, 2015