Alastair J. Glossop

BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults

### Principles of mechanical ventilation #### Modes of mechanical ventilation Recommendation 1. Pressure-targeted ventilators are the devices of choice for acute NIV (Grade B). Good practice points #### Choice of interface for NIV Recommendation 2. A full face mask (FFM) should usually be the first type of interface used (Grade D). Good practice points #### Indications for and contra-indications to NIV in AHRF Recommendation 3. The presence of adverse features increase the risk of NIV failure and should prompt consideration of placement in high dependency unit (HDU)/intensive care unit (ICU) (Grade C). Good practice points #### Monitoring during NIV Good practice points #### Supplemental oxygen therapy with NIV Recommendations 4. Oxygen enrichment should be adjusted to achieve SaO2 88–92% in all causes of acute hypercapnic respiratory failure (AHRF) treated by NIV (Grade A). 5. Oxygen should be entrained as close to the patient as possible (Grade C). Good practice points

British Thoracic Society/Intensive Care Society Guideline for the ventilatory management of acute hypercapnic respiratory failure in adults

The British Thoracic Society (BTS) published the guideline ‘The use of non-invasive ventilation in acute respiratory failure’ in 2002.1 This was in response to trials that had demonstrated that non-invasive ventilation (NIV) was an alternative to invasive mechanical ventilation (IMV) in life-threatening respiratory acidosis due to acute exacerbations of chronic obstructive pulmonary disease (AECOPD). It drew attention to evidence that, when NIV was used in the less severely unwell patient, it also limited progression to more severe respiratory failure.2 The trial also demonstrated the feasibility, of delivering NIV on general medical or admission wards that had enhanced support and when staff were provided with ongoing training. In subsequent years, NIV has been shown to deliver better rather than equivalent outcomes to invasive ventilation in AECOPD and better evidence has accumulated for the use of NIV in non-COPD disease in the intervening years. Repeated national audits have, however, raised concerns that expected patient benefit is not being delivered and have pointed to a number of process deficiencies.3–5 There is also the risk, in the absence of justifying trial evidence, that the preferred use of NIV in AECOPD might be extended to all hypercapnic patients, irrespective of circumstance or underlying disease process. That this is a real risk might be inferred from the BTS audits where the indication for NIV was not COPD in over 30% of cases.3 ,4 NIV development in the UK has been largely outside the organisational ‘umbrella’ of critical care. This may have adversely affected resource allocation and contributed to a lack of integration in NIV and IMV patient pathways. Other unintended consequences might be a restriction on access to invasive ventilation and delay in the development of extended applications of NIV, such as accelerating extubation and its use in the management of …

British Thoracic Society Quality Standards for acute non-invasive ventilation in adults

Introduction The purpose of the quality standards document is to provide healthcare professionals, commissioners, service providers and patients with a guide to standards of care that should be met for the provision of acute non-invasive ventilation in adults together with measurable markers of good practice. Methods Development of British Thoracic Society (BTS) Quality Standards follows the BTS process of quality standard production based on the National Institute for Health and Care Excellence process manual for the development of quality standards. Results 6 quality statements have been developed, each describing a standard of care for the provision of acute non-invasive ventilation in the UK, together with measurable markers of good practice. Conclusion BTS Quality Standards for acute non-invasive ventilation in adults form a key part of the range of supporting materials that the Society produces to assist in the dissemination and implementation of guideline’s recommendations.

Noninvasive Mechanical Ventilation in Acute Ventilatory Failure: Rationale and Current Applications

Noninvasive ventilation plays a pivotal role in acute ventilator failure and has been shown, in certain disease processes such as acute exacerbation of chronic obstructive pulmonary disease, to prevent and shorten the duration of invasive mechanical ventilation, reducing the risks and complications associated with it. The application of noninvasive ventilation is relatively simple and well tolerated by patients and in the right setting can change the course of their illness.

Noninvasive ventilation strategy for weaning from mechanical ventilation for underlying COPD: How to get to be great being little?

Lung India • Vol 32 • Issue 1 • JanFeb 2015 than the controls, who were weaned using invasive PS weaning. It is possible that the benefits demonstrated by the authors are a reflection of the impact of reducing the incidence of VAP rather than benefits of NIV per se. It has been suggested from previous studies that the mortality benefits of using NIV in immunocompromised patients are mainly due to a reduction of the risks of developing VAP,[4] and perhaps we are just seeing another example of this effect in patients with COPD. The high mortality rate seen in the control group may also be a reflection of the incidence and impact of VAP in ventilated COPD patients.

Inclusion of sepsis and hypoxaemia in mortality prediction of hospitalized patients with community‐acquired pneumonia

See Reply

Community-Acquired Pneumonia and Outcome: Is There a Sensitivity Link to Distribution Width Value of Red Cell?

We read with great interest the study by Gorelik et al. [1] regarding the outcomes of patients hospitalised with community-acquired pneumonia (CAP) according to changes in red cell distribution width (RDW). RDW values have been demonstrated to predict morbidity and mortality in several patient populations, but there are few studies investigating the relationship between outcomes of CAP and RDW [2]. The authors performed a retrospective single-centre study of 980 patients with CAP between January 2009 and December 2012. Outcomes including transfer to the intensive care unit (ICU), requirement for mechanical ventilation (MV), prolonged hospital stay and all-cause mortality were measured. Patients were grouped according to stable or changing RDW during hospitalisation, and normal (B14.7%) or high ([14.7%) RDW values on admission and discharge. The authors found that patients with changing RDW were more likely to be transferred to ICU, require MV, need prolonged hospitalisation and had an increased mortality compared to patients with stable RDW. Additionally, patients with a higher admission RDW were more likely to require MV and have a longer length of hospital stay. Mortality was significantly greater in patients with a high RDW at admission and discharge separately, with every 1% increment of RDW a strong predictor of reduced survival. Several key aspects of this important study warrant further discussion. They emphasise the time-dependent changes in RDW during hospitalisation as an important predictor of clinical outcomes in CAP patients. However, it is not able that the duration of differences between RDW measurements was significantly different between groups 5.9 ± 6.0 and 9.6 ± 11.0 days, respectively, in the stable and changing RDW groups. This difference may have influenced the primary outcomes of study. It is not clear from the discussion why the measurement intervals are so different— perhaps due to the retrospective nature of the study, RDW measurements were made randomly? The choice of 14.7% as the cut-off point for RDW size warrants consideration. RDW is reported as the coefficient of variation of red blood cell volume. The laboratory upper limit of 14.7% was cited with no mean and median values provided. Was this value close to mean RDW of the study group? If not, it represents a potential source of bias in the findings. The authors excluded patients with haematological disorders (leukaemia, myelodysplastic syndrome, hemoglobinopathies, etc.), but included patients who were anaemic on admission. An anaemia developing during hospitalisation can reflect the severity of CAP, and thus RDW may be regarded as a marker of high-level inflammatory activity in adults with CAP [3]. The incidence of anaemia in both groups (44.6 vs 46.9%) was similar on admission; however, the change in RDW group had a greater incidence of anaemia at discharge. This difference may be due to & Fatma Yıldırım ftagassi@hotmail.com

Noninvasive mechanical ventilation during spontaneous breathing anaesthesia: Can electrical impedance tomography be a useful bedside tool to titrate PEEP level?

We read with great interest the study by Bordes et al. [1] recently published in the Journal of Clinical Anaesthesia. In this single-centre observational study the authors used electrical impedance tomography (EIT) to assess the effects of noninvasive mechanical ventilation (NIMV) on functional residual capacity (FRC) and ventilation distribution during spontaneous breathing general anaesthesia. A total of 18 patients undergoing gastrointestinal endoscopy (including gastric fibroscopy and colonoscopy) were studied. The authors found that following induction of anaesthesia, ventilation was shifted to non-dependent lung regions and end-expiratory lung impedancemetry was decreased. The findings also suggest that application of NIMV generates a significant increase in end-expiratory lung impedancemetry with no effect on ventilation distribution and a positive effect of NIMV on FRC during spontaneous breathing general anaesthesia. EIT is non-invasive and radiation-free, and allows dynamic imaging and analysis of ventilation at the bedside and in the operating room. EIT monitors display local air changes during ventilation in real time, and although EIT has previously been studied in patients undergoing general anaesthesia there is little data available regarding its use during NIMV [2]. In this aspect the current study is welcomed and we congratulate the authors on their efforts. However we raise several issues that we feel warrant further discussion. Firstly the level of PEEP applied during NIMV in the study warrants debate, as it is generally accepted that obese patients may require higher levels of PEEP [3]. Although the mean body mass index (BMI) of the patients included was 25.6 kg/m great variability was seen; thus an empirically applied 6 cm H2O of PEEP may have been insufficient in those patients whose BMI was greater than 25 kg/m. It is unclear why the authors chose a PEEP of 6 cmH20 for all subjects as 8 patients had a BMI of less than 25 kg/m, and the other 10 had a BMI of 25–36 kg/m and may therefore have been better suited to a higher PEEP. The authors also found that ventilation was shifted to non-dependent lung after induction which contradicts previously reported findings by Radke et al. that suggest spontaneous breathing general anaesthesia prevents the shift of ventilation toward non-dependent lung regions [4]. However it is of note that this study used laryngeal

Comparison and Evaluation of the Effects of Administration of Postoperative Non-Invasive Mechanical Ventilation Methods-in for a Penny, in for a Pound?

Address for Correspondence/Yazışma Adresi: Dr. Alastair J. Glossop E-mail: alastair.glossop@sth.nhs.uk ©Copyright 2016 by Turkish Anaesthesiology and Intensive Care Society Available online at www.jtaics.org ©Telif Hakkı 2016 Türk Anesteziyoloji ve Reanimasyon Derneği Makale metnine www.jtaics.org web sayfasından ulaşılabilir. Received / Geliş Tarihi : 18.07.2016 Accepted / Kabul Tarihi : 19.08.2016 273 Comparison and Evaluation of the Effects of Administration of Postoperative Non-Invasive Mechanical Ventilation Methods-in for a Penny, in for a Pound? Ameliyat Sonrası Non-İnvasiv Mekanik Ventilasyon Yöntemlerinin Uygulanmasının Etkilerinin Karşılaştırılması ve DeğerlendirilmesiHerşeye Rağmen Devam Edilmeli mi?