4 Committee discussion
PneuX is an innovative technology which shows promise for preventing ventilator-associated pneumonia (VAP)
4.1 The clinical experts who had experience of using PneuX explained that it differed from other endotracheal tubes (ETTs) with subglottic drainage because of several design features such as the automated pressure cuff and fold-free, soft, flexible material. The clinical experts noted that the automated pressure cuff is good at preventing micro-aspirations because it maintains a tight seal, even when the patient is moving, and subglottic drainage and irrigation can be done. The committee agreed that PneuX has an innovative design and there is a plausible clinical benefit. But it concluded that there is currently no evidence to show that its additional features, particularly the ability to perform subglottic irrigation, convey any benefits to patients over other ETTs with subglottic drainage.
4.2 The only comparative study for PneuX was in people who had cardiac surgery and who were classified by the investigators as at higher risk of complications (including VAP) because they were over 70 or had impaired left ventricular function (or both). The committee noted that people in the Gopal et al. (2014) study were ventilated for a relatively short period of time (less than 24 hours). The expert advisers explained that people who are ventilated in general intensive care have a much broader range of underlying conditions and complications. The committee concluded that, although there was evidence that PneuX reduces VAP compared with ETT without subglottic drainage in the high-risk cardiac surgical population, this evidence could not be generalised to all people needing ventilation.
4.3 The use of an ETT with subglottic drainage is a recommended part of care bundles for preventing VAP (for example, The Faculty of Intensive Care Medicine's guidelines for the provision of intensive care services). The clinical experts stated that introducing subglottic drainage ETTs has reduced VAP by up to 50%, and that they are now standard care in the NHS. The committee noted there are no studies that directly compare the incidence of VAP with PneuX and other ETTs with subglottic drainage. Therefore, the committee concluded that there was no evidence for additional clinical benefits of using PneuX compared with other ETTs with subglottic drainage.
In the main evidence for PneuX people were ventilated for less time than usually needed to develop VAP
4.4 In the Gopal et al. (2014) study, patients were ventilated for a median time of 15 hours with PneuX and 13 hours with ETT without subglottic drainage. The definitions for VAP state that patients will have been ventilated for a minimum of 24 or 48 hours. The clinical experts explained that it was possible to develop VAP in less than 24 hours and that this was more likely in a high-risk cardiac surgery population. The clinical experts estimated that patients in a wider intensive care population are likely to be ventilated for a median of 2 to 3 days but advised that this may be much longer in some patients. One clinical expert stated that they would use PneuX in people who are expected to be ventilated for longer than 12 hours. But all experts agreed that it is difficult to predict how long ventilation will be needed for. The committee concluded that the evidence collected from people having cardiac surgery in the Gopal study may not accurately represent all people having ventilation in hospital.
4.5 The clinical experts explained that there are several definitions for VAP that incorporate clinical, radiological and microbiological testing. These definitions are used variably both in clinical practice and in the published studies. The clinical experts also explained that VAP incidence may not be recorded accurately in many centres. The committee recognised that all of these factors make research into VAP prevention particularly challenging and limit the legitimacy of between-study comparisons in this area.
4.6 NHS England reports that between 3,000 and 6,000 people die from VAP each year. The clinical experts noted that VAP is also likely to lead to an increase in the length of time ventilation is needed, length of critical care and hospital stay, risk of recurrent pneumonia, prolonged illness and spread of infection to other organs. The committee noted that the studies for PneuX were underpowered to measure any difference in mortality and length of stay, and so concluded that it is uncertain whether PneuX has any impact on these outcomes.
4.7 The company described to the committee how it provides training and support for all staff and centres using PneuX. The company offers a range of training sessions to all staff, lasting between 1 and 4 hours, which can be delivered in a classroom, or by the bedside, as needed. The clinical experts confirmed that the support from the company was adequate to train staff how to use PneuX correctly.
A higher volume of secretions drained and irrigation may slightly increase nurse time for subglottic drainage
4.8 The clinical experts with experience of using PneuX noted that a higher volume of secretions can be drained with PneuX than with other ETTs with subglottic drainage, and that subglottic irrigation, when undertaken, takes an additional 2 to 3 minutes. The committee concluded that using PneuX may lead to a slight increase in nurse time spent on subglottic drainage and irrigation.
The company model is robust but it is not certain that the cost savings will apply to all people needing ventilation
4.9 The committee noted that the company's model was well constructed and robust to uncertainty. It showed that PneuX is cost saving compared with ETTs without subglottic drainage in a high-risk cardiac surgery population. However, the main cost driver in the model was the absolute reduction in the risk of VAP between the PneuX and ETT without drainage arms. As these values were sourced from the Gopal et al. (2014) study, the committee concluded that there was substantial uncertainty that the cost savings would be realised for all people needing ventilation.
Comparisons between PneuX and other ETTs with subglottic drainage may be more appropriate for the NHS
4.10 The committee heard from the clinical experts that subglottic drainage is becoming standard practice in the NHS. The external assessment centre (EAC) modelled an indirect cost comparison of PneuX with Portex Blue Line. However, the committee felt there was considerable uncertainty in this because of the lack of comparative evidence. The committee concluded that the uncertainties associated with this analysis, as well as the small cost difference in results, meant that this was not enough evidence on which to base a positive recommendation. Overall, the committee considered that the current economic evidence does not support the routine adoption of PneuX in the NHS.
4.11 The committee concluded that further research would help resolve the uncertainties about the potential benefits of using PneuX. The research should determine if using PneuX reduces:
VAP incidence in all people needing ventilation
VAP incidence compared with other ETTs with subglottic drainage (including the effect of subglottic irrigation)
time on a ventilator, and critical care and length of stay in hospital mortality.
In this research, the committee recommended that the:
criteria used for defining VAP should be carefully considered and recorded
use of PneuX should be considered within the context of the wider care bundle for VAP prevention
population recruited should be large enough and follow up long enough to capture the important clinical endpoints.