This tutorial is about weaning from mechanical ventilation. This is not an easy topic because every professional in the ICU has their own weaning method and their own opinions regarding how best to wean and liberate patients. The literature is unhelpful. Some patients, for example those who have been intubated for a brief period of time, can be awoken and the tube removed after a couple of spontaneous breaths. Other patients require careful multidisciplinary activity over weeks to months to liberate. This tutorial focuses on the in-between group patient who have been intubated for a week or so, who require both clinical and mechanical assessment of their ability to wean and liberate from the ventilator.
Generally the first intervention in weaning is to change the patient over to a spontaneous breathing mode - pressure support or volume support and ensure that alveolar ventilation is adequate to maintain CO2 clearance. Then a number of clinical and mechanical assessments can be made: is the patient awake, do they have a cough, are they triggering adequately, what is their rapid shallow breathing index (RSBI)? One can estimate muscle strength by performing an occlusion test - either a partial occlusion (P0.1) or a longer occlusion (NIF). Once the patient is assessed as being a candidate for weaning, then one can perform a spontaneous breathing trial (SBT) that is either supported (PS, VS, ATC) or unsupported (T-piece, C-circuit, Trach mask, Swedish Nose). If the SBT is successful after 90 minutes - extubate the patient.
SBTs may fail due to worsening hypoxemia, hypercarbia or hypocarbia, respiratory distress (increase RSBI or use of accessory muscles) or cardiovascular instability (hypotension, hypertension, tachycardia, bradycardia, arrhythmias) or falling levels of consciousness, agitation or acute delirium.
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Contents
00:09 Introduction
01:10 Clinical Scenario
02:00 Evaluating Suitability For Weaning
03:04 Terminology - Weaning vs Liberation, SBT, UBT
06:00 Changing the Patient Over to A Spontaneous Mode
07:08 Weaning Measurements
07:50 RSBI (rapid shallow breathing index)
12:10 P0.1
16:30 NIF (negative inspiratory force)
19:10 Weaning Strategy
19:22 Types of Patients that You Wean From Mechanical Ventilation
22:40 Spontaneous (supported) Weaning Trials (SBT) with Pressure Support
22:55 Peak Inspiratory Flow During SBT
27:40 SBT with Automatic Tube Compensation
29:45 Unsupported Breathing Trials (UBT) - T-Pieces, C-CIrcuits, Trach Masks etc.
35:30 The End of the SBT
36:43 Why SBTs Fail
39:00 Failure to Wean
41:35 Review