Wessex ICS Blog

Regional ICM teaching - Respiratory with focus on weaning

Date: 18th June 2014
Facilitators: Dr Tim Martingdale & Dr Kayode Adeniji
Summary written by: Dr Tim Martindale

Journal presentations - James Keegan and Ben Thomas. Historical papers looking at how and why we have developed the weaning strategies that we now have in place.

a) James Keegan - NEJM Esteban et all 1995. A comparison of four methods of weaning patients from mechanical ventilation.
  • A cohort of mechanically ventilated patients, inclusion criteria was ventilated for over 24 hours. Randomised to PS/IMV/SBT (Spontaneous breathing trial) with weaning.
    • Difference noted at day 4 with SBT groups with increased probability of weaning. Large proportion of extubations with SBT.
    • This paper effectively put to be the use of IMV as a weaning technique.

b) Ben Thomas - Am J Respir Crit Care Med 1994. Brochard et al. Comparison of three methods of gradual withdrawal from ventilatory support during weaning from mechanical ventilation.
  • 3 modes of weaning from ventilator – T piece, SIMV, PSV. Less time apent ventilated than Esteban (>24 hours). Successful weaning defined as no ventilation for over48 hours. Failure conversely was reintubated within 48 hours post or struggling at 21 days.
    • 456 met inclusion, 109 failed SBT
    • Results: 23% failed at PSV at 21 days (p=0.05), decreased length of stay PSV had significantly fewer failures at 21 days.

The physiology perspective on weaning patients – Susan Calvert (Senior critical care physiotherapist, QA hospital)
a) Group discussion on reasons for failing weaning focussing on
i. Load eg Pleural effusions, extra pleural, fat, rib fractures, fibrosis
ii. Capacity eg Cardiovascular reserve, neuromuscular fitness
iii. Patient drive eg Cognitive engagement, reserve
b) Strategies aimed at optimising all components, eg cough assist, re-expansion manoeuvres etc
c) Rehabilitation improved by strength exercise. Avoidance of NMB and steroids.
d) Motivators, sedation level prompts by PT to nursing staff and doctors, increase mood by excursions etc.

Journal presentation - Balas et al, Effectiveness and Safety of the Awakening and Breathing Coordination, Delirium Monitoring/Management, and Early Exercise/Mobility Bundle. Crit Care Med

a) Multi centre trial attempting to create a multi-bundle package to firstly identify practicalities of implementation
b) Primary endpoint – number of ventilator free days (VFD) in cohort
c) Secondary endpoints
Prevalance, duration of ICU days of delirium and coma.
Mobilised from bed during ICU stay?
28 day ICU and total hospital mortality
d) 3 day reduction in VFDs, slight reduction in delirium, no difference in mortality
e) BUT very small numbers for 18 month trial, difficulty recruiting due to complexity, poor bundle adherence.

Bronchoscopy indications and practicalities - Dr Lesley Bishop
a) Indications for performing - lobar collapse, haemoptysis, diagnosis, biopsies
i. Lobar collapse - 4 case series and one case report (n=47). Good immediate outcomes.
ii. Hameoptysis – control of bleeding. But consider rigid bronch or IR as 1st line. One study showed increase rate of diagnosis from bronch (89%) vs CT (80%)
iii. Infection – BAL/Brush. Systemic review 2008, no difference in mortality, los. Bronchoscopy not superior to less invasive strategies as a diagnostic strategy. Used only if unable to identify an organism.
iv. Transbronchial Biopsies – Single case series, established diagnosis in 46%. Significant complications (31%) 2 pneumothoraces, 1 Haemorrhage, 1 Arrhythmia. n=13
v. Needle biopsies. 1 series (n=8) Sens 83&, Spec 100%, 63% led to change in management.
b) Discussion around procedures and equipment.

Weaning from mechanical venitation – Dr Kay Adeniji

a) Weaning from mechanical ventilation Statement of the 6th international consensus conference on ICM – seminal paper
b) Definitions:
i. Simple weaning
ii. Difficult weaning – 3 SBT or over 7d post initial SBT
iii. Prolonged weaning
c) Rapid shallow breathing index >100 = failure, Insp pressure >20 = failure (both very good NPV)
d) Emphasis of daily assessment of SBT 20-120 minutes (he uses 30 mins)
e) You must determine cause of failure of SBT
f) A cochrane analysis of use of a weaning protocol in the management strongly favours protocol (I2 97%) but no effect on mortality or los
g) Failure to ventilate generally occurs at 5 days. Use of bundles in ICU increases ventilator free days in a single centre study.
h) Prolonged weaners are those with ARDS, CHF/CAD, COPD
i) Summary of key points from respiratory weaning centres:
i. Ventilate adequately
ii. Get diagnosis right eg sepsis (persistent CRP), resp fluid overload, arryththmia, motivitaion
iii. Normalise bulbar function
iv. Wean to the appropriate level of support

Summary of Wessex Neurocritical Care Forum at WICS 2014

After the meeting of the inaugural Wessex Neurocritical Care Forum at WICS 2014 Summer Symposium 6th June 2014 the following three areas were discussed and actions to be addressed:
1) Review of Level 3 transfers to WNC Neurocritical Care

This is to be undertaken by Dr Kevin Boyle (Consultant in Neurocritical Care) and he will give feedback to referring hospitals for a six month period from July 2014.
2) Development of Forum Links with each of the referring hospitals:
If interested individuals would like to be involved with developing clinical links between the WNC Neurocritical Care Unit and their  hospital please could you email Dr Roger Lightfoot, Clinical Director of Neurointensive Care

3) Development of Neurocritical Care Level 3 advice line.
Dr Lightfoot to discuss and feedback to Forum Links on how WNC Neurocritical Care can offer a direct line service for complex Level 3 patients. This will probably be between 08:00 - 22:00 in the first instance.
Any other questions please feel free to email Roger Lightfoot at the above email address.
Roger Lightfoot
Clinical Director of Neurointensive Care
Wessex Neurological Centre