Should we be using cuffed or uncuffed tracheal tubes in children?

Cuffed vs Uncuffed tracheal tubes in children: a randomised controlled trial comparing  leak, tidal volume and complications. NA Chambers et al, Anaesthesia 2018  73, 160-168. Doi:10/1111/anae14113

Background

Children’ s tracheas have traditionally been intubated with uncuffed tracheal tubes (TT) due to differences between adult and paediatric subglottic anatomy, and fears that cuffs may lead to mucosal damage and subglottic stenosis. Despite this, cuffed TTs are increasingly used in paediatric anaesthesia.

Over the last 20 years, evidence suggests that cuffed TT may have advantages over uncuffed, and are associated with at least similar, if not superior, airway outcomes when compared with uncuffed TT in children.

 

Aim

This study is the first randomised controlled trial to compare leakage and tidal volumes in cuffed vs. uncuffed TT in the operating theatre in children during standardised mechanical ventilation.

 

Method

  • Single centre randomised controlled trial
  • Adequately powered study based on pilot study at same institution
  • Exclusion Criteria : <5kg, non-elective surgery, abnormal airway, airway surgery and need for post-operative mechanical ventilation.
  • Children <6 and children 6-16 were randomised separately.
  • Leak was calculated by subtracting expiratory volume from inspiratory volume and a mean of 5 measurements taken during VCV 6ml//kg TV,  followed by PCV 10/5. During PCV measurements taken measurements taken post recruitment manoeuvre and 0, 10 and 20 minutes. Perioperative adverse events were recorded and pre discharge post-operative review was conducted for morbidity. Patients were followed up for a minimum of 3 years for potential airway complications.
  • 151 patients eligible. 104 recruited
  • 52 <6yrs old and 52 patients >6yrs old both groups randomised to cuffed or uncuffed groups
  • 18 patients excluded in uncuffed group 6 in <6yrs  group and 12 in >6yrs group. Due to unspecified tube related problems.

 

Results

  • Statistically significant difference in leak between cuffed and uncuffed tubes. In the <6yrs group difference in leak was sometimes up to 25%. Trend for leak to increase over time and tidal volume to fall over time in uncuffed group.
  • With respect to sizing – 80% 1st time tube size selection with cuffed tube vs 32% 1st time correct tube size selection with uncuffed tubes. Almost 25% of uncuffed tubes needed changing post insertion.
  • Significant difference in incidence of sore throat post operatively.
  • No episodes of stridor or long term complication incidence

 

Discussion

Strengths

  • Randomised
  • Adequately powered
  • Relevant question within the context of cuffed tube technology improving and evolution in clinical practice towards cuffed tubes in paediatrics.

Weakness

  • Single centre
  • Increasing use of cuffed tubes makes users less experienced at sizing uncuffed tubes potentially accounting for high reinsertion rates for uncuffed tube.
  • Age/4+4 a measurement for red rubber tube sizing originally Age/4+4.5 used for plastic tubes typically. The uncuffed tubes in this study were biased to selecting tubes half a size too small. The study shows that if you select an uncuffed tube that is too small you will have a larger leak than a cuffed tube.

Cuffed tube Cons

  • Cost cuffed tube £7 uncuffed tube £1
  • Availability of cuffed tubes – often shortages lack of stock.
  • Smaller ID of cuffed tubes risks > resistance and require smaller suction catheters and more prone to kinking.
  • Accurate continuous cuff pressure monitoring is difficult in cuffed tubes.

Cuffed tube Pros

  • Fewer airway manipulations and ETT changes
  • More reliable ventilation and less leak.
  • No difference in major complication rates.
  • If uncuffed fails then we reach for cuffed tubes.

 

Conclusion

With experience correct uncuffed tube selection renders tube changes and leaks a minor issue, however the direction of travel seems to be towards cuffed tubes. The NHS has yet to acquire a reliable supply chain at a reasonable cost. But this paper will contribute to the continuing evolution in practice towards cuffed ET tubes in paediatric anaesthesia.

 

Summary by Dr Usman Ali

 

 

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