+ 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

Added work of breathing, respiratory pattern and determination of ventilator weaning readiness in inspiratory pressure support and and automatic tube compensation



Added work of breathing, respiratory pattern and determination of ventilator weaning readiness in inspiratory pressure support and and automatic tube compensation



Der Unfallchirurg 99(10): 764-770



We measured the ventilatory pattern and additional work of breathing (WOBadd) at three different levels of inspiratory pressure support [IPS 5, 10, 15 mbar above positive end-expiratory pressure (PEEP)] and in a new ventilatory mode, automatic tube compensation (ATC), in nine operative patients without lung injury nine patients ventilated for several following acute respiratory insufficiency (ARI). In ATC, endotracheal tube resistance is compensated automatically by means of closed-loop control of the calculated tracheal pressure. Pressure support in this mode, i.e. airway pressure above PEEP, is equal to the actual flow-dependent pressure drop across the endotracheal tube (ETT). Airway pressure rises at the beginning of inspiration and falls towards the end. As the tube resistance of ETT seriously hinders expiration and can cause desynchronization between ventilator and patient, airway pressure is reduced below PEEP during expiration in the same way as it is increased during inspiration. The result is a near-constant tracheal pressure at PEEP both during inspiration and during expiration. This mode could be best termed as "electronic extubation". The most striking difference between the postoperative patients and the ARI patients was their minute ventilation (17.8 +/- 1.85 l/min in ARI patients vs 7.3 +/- 3.1 l/min in the postoperative patients). In the postoperative patients augmentation of IPS from 5 to 15 mbar induced a steady increase in tidal volume (VT) and a consecutive decrease in respiratory rate (rr) compared with ATC (VTATC,postop = 463 +/- 78 ml; rrATC,postop = 16 +/- 4 min-1; VTIPS5.postop = 505 +/- 79 ml; rrIPS5,postop = 15 +/- 4 min-1; VTIPS10,postop = 562 +/- 86 ml; rrIPS15,postop = 14 +/- 4 min-1; VTIPS15.postop = 660 +/- 151 ml; rrTPS15,postop = 12 +/- 4 min-1), whereas the augmentation of IPS of 5 and 10 mbar in the ARI patients could not compensate for the increase in rr and the decrease in VT, after switching from ATC to IPS (VTATC,ARI 724 +/- 308 ml, rrATC,ARI = 24 +/- 6 min-1; VTIPS5,ARI = 649 +/- 315 ml; rrIPS5,ARI = 27 +/- 8 min-1; VTIPS10,ARI = 653 +/- 353 ml; rrIPS10,ARI = 25 +/- 8 min-1: Even IPS 15 was not able to reestablish VT at the values observed during ATC (VTIPS15,ARI = 680 +/- 312 ml). During ATC WOBadd was small in both postoperative and ARI patients (WOBadd,ATC,postop = 93 +/- 36 mJ/l, WOBadd,ATC,ARI = 116 +/- 72 mJ/l). In the postoperative patients, an inspiratory pressure support of 5 mbar was not sufficient to compensate WOBadd compared with ATC. However, IPS 10 and 15 mbar were able to compensate for WOBadd (WOBadd,ATC5.postop WOBadd,IPS5,postop = 189 +/- 77 mJ/l; WOBadd,IPS10,postop = 55 +/- 30 mJ/l; WOBadd,IPS15,postop = 21 +/- 11 mJ/l). In the ARI patients an IPS 5, 10 or 15 mbar was not sufficient to compensate for WOBadd (WOBadd,IPS 5,ARI = 1126 +/- 262 mJ/l; WOBadd,IPS 10,ARI 863 +/- 253 mJ/l; WOBadd,IPS15,ARI 763 +/- 298 mJ/l). Under ATC, WOBadd was only 15% of WOBadd under IPS of 15 mbar. All but two patients were successfully extubated after the investigation. These two patients were not extubated because they were dependent on an FIO2 > 0.5. Our results strongly indicate that ventilatory dependence in ARI patients may be caused by the ETT rather than by mechanical dysfunction of the lung. ATC is a very helpful mode to use in distinguishing between ventilatory failure caused by ETT and real ventilatory dependence.

Please choose payment method:






(PDF emailed within 1 workday: $29.90)

Accession: 045170881

Download citation: RISBibTeXText

PMID: 9005565


Related references

Added work of breathing, ventilatory pattern and recognizability of readiness for extubation during inspiratory pressure support and automatic tube compensation. Unfallchirurg 99(10): 765-770, 1996

Breathing pattern and additional work of breathing in spontaneously breathing patients with different ventilatory demands during inspiratory pressure support and automatic tube compensation. Intensive Care Medicine 23(5): 545-552, 1997

Additional work of breathing and breathing patterns in spontaneously breathing patients during pressure support ventilation, automatic tube compensation and amplified spontaneous pattern breathing. European Journal of Anaesthesiology 22(4): 312-314, 2005

Respiratory pattern and respiratory strain in automatic tube compensation and inspiratory pressure support. Der Anaesthesist 48(12): 871-875, 1999

Breathing pattern and workload during automatic tube compensation, pressure support and T-piece trials in weaning patients. European Journal of Anaesthesiology 20(1): 10-16, 2003

Breathing pattern and workload during automatic tube compensation, pressure support and T-piece trials in weaning patients. European Journal of Anaesthesiology 20(1): 10-16, 2005

Breathing pattern associated with respiratory comfort during automatic tube compensation and pressure support ventilation in normal subjects. Acta Anaesthesiologica Scandinavica 44(3): 223-230, 2000

The use of an automatic endotracheal tube resistance compensation system during inspiratory pressure support ventilation: analysis of cardiopulmonary function and respiratory mechanics during weaning after emergency cardiac surgery. Clinical Intensive Care 7(2): 95-98, 1996

During pressure support ventilation automatic compensation for endotracheal tube resistance reduces patient work of breathing and improves patient-ventilator sychrony. Intensive Care Medicine 22(1 Suppl.): S122-0, 1996

Spontaneously breathing lung model comparison of work of breathing between automatic tube compensation and pressure support. Respiratory Care 48(1): 38-45, 2003

Comparisons of predictive performance of breathing pattern variability measured during T-piece, automatic tube compensation, and pressure support ventilation for weaning intensive care unit patients from mechanical ventilation. Critical Care Medicine 39(10): 2253-2262, 2011

Comparisons of predictive performance of breathing pattern variability measured during T-piece, automatic tube compensation, and pressure support ventilation for weaning intensive care unit patients from mechanical ventilation. Yearbook of Anesthesiology and Pain Management 2012: 216-219, 2012

Respiratory comfort of automatic tube compensation and inspiratory pressure support in conscious humans. Intensive Care Medicine 23(11): 1119-1124, 1997

Relationship between work of breathing provided by a ventilator and patients' inspiratory drive during pressure support ventilation; effects of inspiratory rise time. Anaesthesia and Intensive Care 29(4): 349-358, 2001

The extra work of breathing due to the endotracheal tube is abolished during inspiratory pressure support breathing. American Review of Respiratory Disease 137(4 Part 2): 64, 1988