Test your IntelliVence (Vol 18 Issue 4)

27.09.2021
Author: Aude Garnero, Intensivist, Hôpital Sainte Musse, Toulon, France, Reviewer: Jean-Michel Arnal, David Grooms, Süha Demirakca

This patient is on pressure support ventilation in NIV. The inspiratory trigger is set at 3 l/min and expiratory trigger sensitivity is set at 50% (of the maximal flow). Why is the inspiratory time so long?

Answer: The inspiratory flow shows a change in slope that corresponds with the relaxation of the inspiratory effort. The inspiratory flow remains high and relatively constant, which means there is a large, unintentional leak.

The leak’s flow rate is higher than the set expiratory trigger sensitivity. This prolongs mechanical insufflation until Ti max - kept at the default value of 2 s – is reached, resulting in a long inspiratory time and delayed cycling.

Therefore, the clinician should try to control leaks by adjusting the interface.  As leaks are common in NIV, Ti max should always be set to 0.2 s longer than the patient’s inspiratory time, measured without leak. This helps to synchronize the end of the mechanical breath with the end of the patient’s inspiratory effort and thus prevent discomfort due to delayed cycling.

 

quiz, pressure support, NIV, leak, inspiratory time, TI, inspiratory flow, ets, expiratory trigger, expiratory trigger sensitivity, cycling, delayed cycling
Back

Date of Printing: 27.11.2021
Disclaimer:
The content of this newsletter is for informational purposes only and is not intended to be a substitute for professional training or for standard treatment guidelines in your facility. Any recommendations made in this newsletter with respect to clinical practice or the use of specific products, technology or therapies represent the personal opinion of the author only, and may not be considered as official recommendations made by Hamilton Medical AG. Hamilton Medical AG provides no warranty with respect to the information contained in this newsletter and reliance on any part of this information is solely at your own risk.
Date of Printing: 27.11.2021
Disclaimer:
The content of this Knowledge Base is intended for informational purposes only. Medin Medical AG provides no warranty with respect to the information contained in this Knowledge Base and reliance on any part of this information is solely at your own risk. For detailed instructions on operating your Medin Medical device, please refer to the official Medin Medical Operator’s Manual for the respective device.