Difficult weaning from mechanical ventilation Paolo Biban, MD Director, Neonatal and Paediatric Intensive Care Unit Division of Paediatrics, Major City Hospital Azienda Ospedaliera Universitaria Integrata Verona, Italy
No conflicts of interest to declare
Introduction Although mechanical ventilation is often life-saving, it can be associated with important complications, such as ventilatorinduced lung injury and nosocomial pneumonia. Endotracheal tubes are uncomfortable for patients and may be associated with airway injury, particularly in mobile young patients, thus increasing the need for adequate sedation.
Introduction It is important that mechanical ventilation be discontinued as soon as the patient is capable of sustaining spontaneous breathing. However, although expeditious weaning and extubation are the goal, premature extubation can be lethal!
Outline Definition of weaning Are there optimal weaning methods..? Clinical markers of extubation success Extubation failure Sedation protocols Non-invasive ventilation
Definitions Weaning is the transition from ventilatory support to completely spontaneous breathing, during which time the patient assumes the responsibility for effective gas exchange while positive pressure support is withdrawn. Spontaneous breathing is a prerequisite for weaning to begin and decreasing ventilator support is not the sole criterion of successful weaning.
Weaning The new weaning classification according to the difficulty and length of the weaning: simple weaning group, including patients who were extubated on the same day as their first attempt of withdrawal from mechanical ventilation; difficult weaning group, including patients who required up to 7 days to be extubated from the first attempt of withdrawal from mechanical ventilation; prolonged weaning group, including patients who required more than 7 days of weaning after the first attempt of withdrawal from mechanical ventilation.
Pediatr Crit Care Med 2009; 10:1-11
Pediatr Crit Care Med 2009; 10:1-11
Liberating the child from the ventilator is the ultimate end game of mechanical ventilation.
Weaning protocols The decision to start weaning depends on the fulfilment of certain clinical criteria, such as: control of what caused the connection to MV effective gas exchange appropriate neuromuscular condition appropriate level of consciousness allowing the protection of airways stable hemodynamic status. other factors...
Which is the optimal weaning method..?
Authors conclusions Limited evidence suggests that weaning protocols reduce the duration of mechanical ventilation, but evidence is inadequate to show whether the achievement of shorter ventilation by protocolized weaning causes children benefit or harm. The Cochrane Library 2013, Issue 7
Conclusions: Automated systems may reduce weaning and ventilation duration and ICU stay. Due to substantial trial heterogeneity an adequately powered, high quality, multi-centre randomized controlled trial is needed.
Extubation failure
Extubation failure Criteria for extubation include spontaneous ventilation, hemodynamic stability, intact airway reflexes, and manageable airway secretions. Success is defined as 24-48 hrs of spontaneous breathing without positive pressure support.
Predictive tests for weaning and extubation success Pulmonary function tests compliance, resistances, TV, MV, etc. RSBI (rapid shallow breathing index, f/vt) MIP or NIF (maximal inspiratory pressure) MVT (minute ventilation test) Volumetric capnography P.01 CROP index Spontaneous breathing test Air leak test
The weaning process and tolerance to endotracheal tube withdrawal are separate phenomena... Weaning success may precede extubation failure due to the persistent need for ETT airway support...
Successful extubation rests on improvement or resolution of the condition supported by the intervention. Other factors affecting extubation success include gas exchange capacity, respiratory muscle strength, laryngeal function and cough strength, nutritional status, psychological state, and dissipation of sedative and muscle relaxant effects. Kurachek et al. Crit Care Med 2003; 31: 2657-2664
Also important are specific care practices directed at: optimal use of sedative and muscle relaxant medications weaning and extubation protocols strategic use of noninvasive positive pressure ventilation early extubation practice for selective surgical populations. Kurachek et al. Crit Care Med 2003; 31: 2657-2664
Kurachek et al. Crit Care Med 2003; 31: 2657-2664
Kurachek et al. Crit Care Med 2003; 31: 2657-2664
Kurachek et al. Crit Care Med 2003; 31: 2657-2664 Failed Extubation Rate. Extubation failure occurred in 174 of the 2,794 patients (6.2%) (95% CI, 5.3, 7.1). The majority of failed planned extubations (83%) occurred within the first 12 hrs, supporting the common practice of extubating patients early in the day.
Kurachek et al. Crit Care Med 2003; 31: 2657-2664
Kurachek et al. Crit Care Med 2003; 31: 2657-2664
Unplanned Extubations. Unplanned extubation took place in 4.6% (136 of 2,930 total patients). Whereas 14.5% of the study population was 6 months old, 48.8% of patients experiencing an unplanned extubation were in this age category! The failure rate for unplanned extubation was 37.5% Kurachek et al. Crit Care Med 2003; 31: 2657-2664
The role of sedation Age and disease-related cognitive and behavioral conditions can limit a child s understanding and cooperation, necessitating enhanced sedative and muscle relaxant use to minimize self-injury and unplanned ETT removal.
On the other end The role of sedation There are recent studies suggesting that mechanically ventilated children are being oversedated in the PICU. The largest of these studies, by Twite et al., found that 27% of children being sedated in a PICU had BIS Monitor values < 40, which are consistent with deep general anesthesia.
Non-Invasive Ventilation to prevent extubation failure
Pediatr Crit Care Med. 2015;16: 418-27
Pediatr Crit Care Med. 2015;16: 418-27
Thanks! paolo.biban@ospedaleuniverona.it