Appendix

Appendix

Contents

Data tables

Table 1: Overview of the Gopal et al. (2015) study

Table 2: Summary of results of the Gopal et al. (2015) study

Table 3: Overview of the Smith et al. (2014) study

Table 4: Summary of results of the Smith et al. (2014) study

Table 5: Overview of the Doyle et al. (2011) study

Table 6: Summary of results of the Doyle et al. (2011) study

Table 7: Summary of Hodd et al. (2009) abstract

Table 1 Overview of the Gopal et al. (2015) study

Study component

Description

Objectives/hypotheses

To assess whether the PneuX system is associated with a reduction in VAP when compared with the standard ET tube in high‑risk patients undergoing cardiac surgery.

Study design

Single centre, randomised controlled trial comparing the PneuX tube with the standard tube. Follow‑up period: 48 hours after extubation. Intermittent subglottic suctioning was performed at 6‑hourly intervals.

Setting

Department of Cardiothoracic Surgery, Heart and Lung Centre, Wolverhampton, UK. Patients were transferred to the ICU post‑operatively.

Inclusion/exclusion criteria

Inclusion criteria: patients over the age of 70 years or with impaired LVEF (<50%) undergoing elective and urgent cardiac surgery.

Patients who were recruited to other studies were excluded.

Primary outcomes

Incidence of VAP.

A diagnosis of VAP was confirmed via the Hospitals in Europe Link for Infection Control through Surveillance (HELICS) definition.

Statistical methods

Power calculations suggested ≥107 patients per group (power of 0.9 and an alpha of 0.01).

Patients included

High‑risk patients undergoing cardiac surgery; n=240 (120 in each group).

Results

VAP incidence was significantly lower in the PneuX tube group than in the standard ET group (10.8% compared with 21%, p=0.03).a

There was no significant difference between the two groups in terms of intensive care unit stay (p=0.2) and in‑hospital mortality (p=0.2).

Conclusions

The PneuX system is associated with a significant reduction in VAP. This can potentially lead to significant cost reductions and should be implemented as part of the VAP reduction bundle.

Abbreviations: CI, confidence interval; ET, endotracheal; ICU, intensive care unit; LVEF, left ventricular ejection fraction; n, number of patients; VAP, ventilator‑associated pneumonia.

a The between‑group difference with 95% CI was not reported in the paper. The External Assessment Centre (principal authors of the briefing) used the presented data to calculate a risk difference of 10% (95% CI 1 to19%) which equates to a number needed to treat of 10 (95% CI 5.3 to 100).

Table 2 Summary of results from the Gopal et al. (2015) study

PneuX tube

Standard tube

Analysis

Randomised

n=120

n=120

Efficacy

n=120

n=120

Primary outcome:

VAP incidence (n;%)a

13 (11%)

25 (21%)

p=0.03

Selected secondary outcomes:

VAP incidence densityb

52

184

<0.01

Survival

98%

99%

p=0.2

Median ICU stay (days)

2

1.5

p=0.2

Re‑exploration (n;%)

17 (14%)

10 (8%)

p=0.2

Median intubation time (hours)

15

13

p=0.5

Mean CPB time (minutes±SD)

110±58

105±62

p=0.3

Mortality (n; %)c

2 (1.6%)

1 (0.8%)

p=0.2

Safety

The anaesthetists reported no difficulties in intubating patients with the PneuX tube. There was no accidental tube displacement or dislodgement.

There was 1 case of a patient experiencing oxygen desaturation following suctioning and irrigation, which resulted in a transient increase in oxygen requirement. The patient was subsequently extubated uneventfully 12 hours later. An independent clinician from an external organisation was asked to comment on whether the patient had potentially aspirated the sterile water during the reported episode. The conclusion was that it was impossible to state with any certainty that the patient had aspirated the sterile water during the period of suction and irrigation. There were no reports of failure of the continuous cuff‑pressure monitoring device.

Abbreviations: CPB, cardiopulmonary bypass; ET, endotracheal tube; EuroSCORE, European system for cardiac operative risk evaluation; ICU, intensive care unit; LVEF, left ventricular ejection fraction; n, number of patients; NR, not reported; SD, standard deviation; VAP, ventilator‑associated pneumonia.

aThe between‑group difference with 95% CI was not reported in the paper. The External Assessment Centre (principal authors of the briefing) used the presented data to calculate a risk difference of 10% (95%CI 1 to19%) which equates to a number needed to treat of 10 (95%CI 5.3 to 100).

bNumber of VAP episodes per 1000 ventilator days.

cNone of the 3 patients who died had VAP.

Table 3 Overview of the Smith et al. (2014) study

Study component

Description

Objectives/hypotheses

To review the impact of the PneuX system on the incidence of VAP and its effects on local practice.

Study design

Retrospective cohort study. Follow‑up period: not reported.

Setting

A mixed medical and surgical ICU, Hull and East Yorkshire Hospitals NHS Trust, in 2010.

Inclusion/exclusion criteria

All patients were intubated with the PneuX system and received its associated care package in the intensive care department during 2010. Identified using both paper and electronic hospital records.

Primary outcomes

Incidence of VAP.

Diagnosis of VAP was based on the recommendations of the American Thoracic Society and the Infectious Diseases Society of America.a Clinical diagnosis of VAP was made if new radiographic infiltrates were present on a chest X‑ray at 48 hours after initial intubation, in combination with at least 2 of the following: fever, leukocytosis, or purulent trachea‑bronchial secretions.

Statistical methods

Not specified. Median (range) was used for the duration of the PneuX system being in place. 95% CI was reported for VAP incidence. The incidence of VAPs/1000 bed days was calculated based on the cumulative total of PneuX system use and the occurrence of VAP.

Results

Three of the 48 patients developed VAP (6.25%, 95% CI 1.3–17%). Two more cases of VAP were excluded due to pre‑existing VAP.

Conclusions

The PneuX system facilitated lower VAP rates than those documented elsewhere and highlighted the incidence of unplanned extubations in local practice. Further evaluation of the implementation of the PneuX system in intensive care areas, in tandem with large‑scale evaluation of its effectiveness, are still required.

Abbreviations: CI, confidence internal; ICU, intensive care unit; VAP, ventilator‑associated pneumonia.

a VAP as diagnosed by the ATS/IDSA guidelines (American Thoracic Society; Infectious Diseases Society of America. Guidelines for the management of adults with hospital‑acquired, ventilator‑associated, and healthcare‑associated pneumonia. American Journal of Respiratory and Critical Care Medicine (2005) 171: 388–416.

Table 4 Summary of results from the Smith et al. (2014) study

Patients included

Forty eight adult patients who were expected to be intubated for at least 24 hours, including 14 who had primary intubation with the PneuX system and 34 who underwent tracheal tube exchange to the PneuX system.

Mean age 57.5 years.

56% male.

Type of patient: 32 medical, 7 surgical and 9 neurosurgical.

Primary outcomes

Three of the 48 patients developed VAP (6.25%, 95% CI 1.3–17%); 2 more cases of VAP were excluded due to pre‑existing pneumonia.

Of the 3 patients who were diagnosed with VAP, the onset of VAP was identified on days 3, 7 and 9 after initial intubation.

Safety

The majority of extubations were planned in advance but 17% (n=8) were classified as unplanned, with a majority (62%, n=5) of these being unplanned self‑extubations. Patient self‑extubation occurred in 13% (n=6) of the 48 patients.a

Physiotherapists commented that the tracheal tube felt 'too long,' which prevented suction catheters entering the trachea sufficiently to provide adequate suction. Some staff felt that while the bite block and lock nut secured the tube in the right position, it also acted as a grip for patients to achieve unplanned self‑extubation.

Abbreviations: CI, confidence internal; ICU, intensive care unit; VAP, ventilator‑associated pneumonia; n, number of patients.

aThe paper stated that "the majority (66%) of extubations were planned. However, of the remaining unplanned extubations, two were deemed to be accidental, where the patient was not responsible for tracheal tube removal, and 5 were classed as self‑extubation. In a single case the tracheal tube was removed for clinical reasons". There are some discrepancies regarding the reported extubation rates.

Table 5 Overview of the Doyle et al. (2011) study

Study component

Description

Objectives/hypotheses

To determine the incidence of VAP in patients who were intubated with the PneuX system and to establish whether intermittent subglottic secretion drainage could be performed reliably and safely using the PneuX system.

Study design

Retrospective cohort study. Follow‑up period: not reported.

Setting

At a Queen Elizabeth Hospital, NHS Trust. Follow‑up period unclear.

Inclusion/exclusion criteria

Sequential critically ill patients aged more than 18 years who received the PneuX tracheal tube and cuff pressure controller for mechanical ventilation during a 14‑month period in that hospital. The use of the PneuX system was restricted to those patients who were anticipated to require more than 24 hours of intubation.

Primary outcomes

Incidence of VAP.

VAP was defined as any pneumonia that occurred after more than 48 hours of intubation and mechanical ventilation with the PneuX system. It was diagnosed by (i) clinical suspicion (including the use of any antibiotics for the treatment of colonisation or infection within the tracheobronchial tree or lungs); and/or (ii) international consensus criteria: the presence of new, persistent pulmonary infiltrates not otherwise explained, appearing on chest radiographs and at least two of the following criteria: temperature of greater than 38 degrees Centigrade; leukocytosis of greater than 10,000 cells/mm3 and purulent respiratory secretions; or (iii) clinical pulmonary infection score (a fall in the PaO2/FiO2 ratio of greater than 25% and a clinical pulmonary infection score of greater than 5 in the presence of bacteria in a qualitative endotracheal aspirate).

Statistical methods

Not specified.

Conclusions

The study demonstrates that a low incidence of VAP is possible using the PneuX system. It also demonstrates that elective exchange and intermittent subglottic secretion drainage can be performed reliably and safely using the PneuX system.

Abbreviations: ICU, intensive care unit; VAP, ventilator‑associated pneumonia.

Table 6 Summary of results from the Doyle et al. (2011) study

Patients included

Fifty‑three critically ill patients aged older than 18 years received the PneuX system. All patients included in the study were intubated with the PneuX system and received mechanical ventilation for more than 48 hours. No patients intubated with the PneuX system were excluded from the analysis.

Primary outcomes

There were a total of 306 days of intubation with a mean of 5.3 days (range 1–18 days).

Forty‑four (83%) patients underwent a tube exchange and 17% were primary intubations with the PneuX system on the ICU.

There were no episodes of VAP while the PneuX system was in situ.

On an ITT basis there was a 1.8% VAP rate as 1 patient, who required reintubation following elective extubation, received a conventional tube and developed a VAP 2 days later with the conventional tube in situ.

No antimicrobial therapy was initiated for chest infections in patients intubated with the PneuX system.

Safety

There were no complications from, or failure of, subglottic secretion drainage during the study.

Abbreviations: ICU, intensive care unit; ITT, intention to treat; VAP, ventilator‑associated pneumonia.

Table 7 Summary of data from the Hodd et al. (2009) abstract

Objectives/hypotheses

To determine the incidence of unplanned extubations using the PneuX system and to compare this with previously reported data. Hypothesis: the incidence of unplanned extubation is decreased when using the PneuX system compared to historical data.

Study design

Retrospective cohort study – analysis of the electronic medical records of ICU patients intubated with the PneuX system.

Setting

At a Queen Elizabeth Hospital, NHS Trust, during the period 2006–2009. Follow‑up period unclear.

Inclusion/exclusion criteria

The electronic medical records of all ICU patients intubated with the PneuX system from 2006–2009 in the hospital.

Primary outcomes

Incidence of unplanned extubation.

Statistical methods

Not specified.

Patients included

A total of 185 intubations with the PneuX system. No further information on the population.

Results

During the 3‑year period there were a total of 185 intubations with the PneuX system and 982 intubation days (mean 5.31, median 4).

There was 1 unplanned extubation (self‑extubation) during that period. This resulted in an incidence for unplanned extubations of 0.1% (1.02 per 1000 intubation days).

Conclusions

The results suggest that the PneuX system compares favourably with figures reported in largest published database (7.6% incidence of unplanned extubation; 9.4 per 1000 intubation days). Engineered efforts to minimise unplanned extubation should be encouraged.

Abbreviations: ICU, intensive care unit; VAP, ventilator‑associated pneumonia.