+ 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

Unrecognized Imposed Resistive Work of Breathing Results in Inadequate Levels of Pressure Support Ventilation in Pediatric Patients with Respiratory Failure



Unrecognized Imposed Resistive Work of Breathing Results in Inadequate Levels of Pressure Support Ventilation in Pediatric Patients with Respiratory Failure



Anesthesiology Abstracts of Scientific Papers Annual Meeting: Abstract No. A-1397



Introduction: Mechanical ventilation with inadequate levels of PSV can contribute to respiratory muscle fatigue. This is especially true in children due to the resistance imposed by smaller diameter endotracheal tubes (ETT). Clinicians currently make ventilator adjustments based on airway pressure measurements obtained at the Y-piece (PY) of the ventilator circuit rather than the distal, intratracheal end of the ETT (PT). However, in healthy children PY underestimates the amount of negative airway pressure generated during spontaneous ventilation, which leads to an underestimation of WOBi.1 Underestimation of WOBi may, in turn, mislead clinicians as to the optimal level of PSV needed to nullify WOBi and avoid respiratory muscle fatigue. We hypothesized that, in children with respiratory failure a large amount of WOBi is unrecognized using PYdata and that this results in the administration of inadequate levels of PSV. Methods: Following IRB approval and parental consent, 22 pediatric ICU patients requiring ventilatory support for respiratory failure were enrolled in this prospective, observational study. All patients had previously been intubated with an ETT with a pressure measuring lumen embedded in its sidewall, which terminated at the tracheal end (Tyco:Mallinckrodt, St. Louis, MO). PY, tidal volume (VT), and peak inspiratory flow rate were measured by a flow-pressure sensor placed between the Y-piece and the ETT. PT was simultaneously measured from the side lumen of the ETT. Both pressure readings were directed to a bedside monitor (CP-100(R), Bicore Monitoring Systems, Irvine, CA) and pressure-volume loops created using PT and VT. WOBi was calculated for repeated spontaneous breaths as the area below the baseline pressure within the loop. The PSV level was documented for each patient at the time of the study. A PSV level that did not reduce WOBi to zero was considered inadequate. Data were analyzed with a repeated measures ANOVA and t-tests with alpha set at 0.05 for statistical significance. Results: The patients ranged in age from 10 days to 21 years and weighed an average of 26.4 kg. Twelve of the 22 children (54%) were determined to have inadequate levels of PSV as evidenced by increased WOBi (Figure). Two patients had particularly high levels of WOBi that was not appreciated clinically and were being inadequately treated with PSV. PY consistently underestimated WOBi compared with PTduring spontaneous breathing. Conclusions: The majority of critically ill children with respiratory failure in this study were found to be receiving PSV at levels insufficient to reduce their WOBi to zero. This is likely due to the fact that PY measurements underestimate patients' actual WOBi and adequate PSV is not prescribed. We recommend that PT be used to calculate WOBi in order to better apply PSV in pediatric patients with respiratory failure.

Accession: 036006343

Download citation: RISBibTeXText


Related references

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

Effects of heat and moisture exchangers on minute ventilation, ventilatory drive, and work of breathing during pressure-support ventilation in acute respiratory failure. Critical Care Medicine 24(7): 1184-1188, 1996

Extubating at a pressure support ventilation level corresponding to zero imposed work of breathing. Anesthesiology 81(3A): A271, 1994

A practical way to decrease imposed work of breathing to zero with pressure support ventilation. Anesthesiology 77(3A): A279, 1992

Decreasing imposed work of the breathing apparatus to zero using pressure-support ventilation. Critical Care Medicine 21(9): 1333-1338, 1993

Pressure Support Ventilation and Other Approaches to Overcome Imposed Work of Breathing. Neoreviews 7(5): E226-E233, 2006

Effects of different positive end expiratory pressure and pressure support ventilation levels on breathing pattern in acute respiratory failure. European Journal of Anaesthesiology 18(Suppl. 21): 112, 2001

The effect of pressure support ventilation on the work of breathing in pediatric patients. Anesthesiology 77(3A): A1247, 1992

Correlation between the %MinVol setting and work of breathing during adaptive support ventilation in patients with respiratory failure. Respiratory Care 55(3): 334-341, 2010

Effect of different levels of pressure support on physiological variables and patient-ventilator synchronicity during noninvasive pressure support ventilation in patients with respiratory failure. Zhongguo Wei Zhong Bing Ji Jiu Yi Xue 22(7): 405-409, 2010

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

Imposed Work of Breathing During High-Frequency Oscillatory Ventilation in Spontaneously Breathing Neonatal and Pediatric Models. Respiratory Care 63(9): 1085-1093, 2018

Tracheal pressure control provides automatic and variable inspiratory pressure assist to decrease the imposed resistive work of breathing. Critical Care Medicine 30(5): 1106-1111, 2002

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