Asynchrony and DyspneaDiscussion

Abstract

SummaryPatient-ventilator synchrony and patient comfort are assumed to go hand in hand, yet few studies provide support for this common sense idea. In reality, synchrony between the patient and ventilator is complex and can be affected by the ventilator settings, type of ventilator, patient-ventilator interface, and sedation. Inspections of airway pressure and flow waveforms are reliable methods for detecting asynchrony, and automated detection seems accurate. A number of types of asynchronies have been defined, and asynchrony during invasive and noninvasive ventilation have different calling cards. There is a clear association between asynchrony, ventilator-induced diaphragmatic dysfunction, and duration of mechanical ventilation. Whether these are cause and effect or simply associated remains to be determined.

Identifying Patient-Ventilator Asynchrony Using Waveform Analysis

“…Ineffective effort is defined as "patient efforts that are not sensed by the ventilator" [6]. In other words, the patient generates an inspiratory effort, but the ventilator does not recognize it and does not deliver a breath to the patient.…”

“…Several authors point out that the interpretation of PVA using waveform analysis, is a skill that every health care professional who is in contact with ventilated patients, should develop in order to prevent their appearance and their complications associated [3,[5][6][7][8][9] [ Table 1]. However, the interpretation of PVA is a skill that requires specific training.…”

Cardiorespiratory Interactions: The Relationship Between Mechanical Ventilation and Hemodynamics

“…In the situation in which V O 2 is excessive in relation to oxygen delivery, the clinician should consider treating patient-ventilator dyssynchrony, titrating ventilator support to provide an appropriate patient work of breathing, and avoiding excessive patient agitation, shivering, and hyperthermia. 20,21 Patient-ventilator dyssynchrony [22][23][24] can lead to excessive V O 2 by the respiratory muscles. Dyssynchrony can be flow-related or trigger-related and occurs when spontaneous inspiratory effort is out of phase with the ventilatordelivered breaths.…”

“…Dyssynchrony can be flow-related or trigger-related and occurs when spontaneous inspiratory effort is out of phase with the ventilatordelivered breaths. [22][23][24] When dyssynchrony is present, primary hypoxemia due to ventilation/perfusion mismatching, mucous plugging, pneumothorax, and reactive airway disease must be eliminated as the etiology. When these causes are eliminated, altering the mode (ie, inspiratory flow pattern), improving the trigger sensitivity, or increasing the support provided by the ventilator may improve patientventilator synchrony.…”

Respiratory Care Year in Review 2013: Airway Management, Noninvasive Monitoring, and Invasive Mechanical Ventilation

“…Three very interesting reviews [46][47][48] highlighting the importance of the interpretation of asynchronies between the patient and the mechanical ventilator were published during 2013. Patient-ventilator asynchronies are common, decrease comfort, prolong mechanical ventilation and ICU stay, and might lead to worse outcome.…”