Background
For a few decades, non-invasive ventilation (NIV) has been regarded as an effective method in avoiding the use of endotracheal intubation (ETI) and decreasing mortality in patients with acute hypercapnic respiratory failure (AHRF). Recent evidence supports the suggestion that the inclusion of NIV into conventional intervention strategy may enhance outcomes in both patients with chronic obstructive pulmonary disease (COPD) exacerbation and those with acute cardiogenic pulmonary oedema (1). However, the effectiveness of NIV in patients with acute conditions after operations and in trauma is still questioned. A meta-analysis in 2015 suggested that the use of NIV as an adjunctive therapy in non-COPD and non-traumatic AHRF patients decreases the need for ETI, ICU length of stay, and mortality rate to significant levels (2). However, they concluded that the heterogeneity of the cohorts in the studies did not allow for definitive recommendations and further studies were required.
Home mechanical ventilation (HMV) in the form of NIV is also an increasingly common intervention and is initiated for a range of pathological processes, including neuromuscular disease (NMD), chronic obstructive pulmonary disease (COPD) and obesity-related respiratory failure (3). Physiologic studies have shown that mechanical ventilation can improve alveolar ventilation while reducing inspiratory effort in patients with stable chronic hypercapnic respiratory failure (4). A number of potential mechanisms have been proposed to explain the beneficial effects of NIV in hypercapnic patients with COPD, including an increase in the central responsiveness to CO2, which is associated with improved daytime blood gases, changes in lung mechanics, improvement in ventilation/perfusion (V/Q) matching, recruitment of non-ventilated or poorly-ventilated alveolar units, and decreased pulmonary hypertension (5). Nevertheless, for over twenty years, the mentioned issues provoke many controversies.
Aim and Hypothesis
The study will answer the following question: can NIV implementation in patients with non-COPD be considered effective and what factors will define its efficacy?
The formulated hypothesis is as follows: the application of NIV in the adjunctive treatment of non-COPD patients will help to reduce the need for ETI, the length of stay at intensive care unit, and the overall mortality rates. However, it is suggested that, in order to ensure a high level of NIV efficiency, the personnel should set up the ventilation parameters considering the distinctive properties of NIV which include oxygen leakages and additional variable resistance of the upper respiratory tract (6). Thus, the research also aims to determine what NIV regimes and intervention factors will be associated with greater efficiency and better patient outcomes in the treatment of non-COPD.
Methods
The research project will be carried out in three phases:
The systematic review and meta-analysis of evidence on the use of NIV in acute and postoperative care for non-COPD respiratory failure and postoperatively.
The given methodology is selected because the findings of systematic reviews are frequently far more valuable than the results of a separate study mainly due to the larger size of the sample (7). The data collected from about 200 scholarly and professional sources will be examined at this stage. Both qualitative and quantitative paper will be analysed. The major selection criterion will be the sample composition − it should consist of over 50 percent of non-COPD patients. Such databases as MEDLINE, and NCBI will be utilised to locate the articles. The given phase of the study will be completed in six months, and the results may then be used to form recommendations for the further study and practice.
A retrospective analysis of NIV implementation in acute respiratory failure using the data collected from Heart of England NHS Trust and University Hospital Birmingham NHS Trust.
The purposes of this cohort study include the evaluation of outcomes and failure rates associated with NIV application, as well as its impacts on the length of stay, and links between various physiological markers (e.g., pH, SaO2, and FEV1) and NIV failure. Some researchers suggest using NIV when a patient shows the following signs of gas exchange abnormality: PaCO2> 45 mmHg (8) and pH < 7.35 (9). However, these findings are primarily related to patients with CODP and, therefore, there is a need to identify the optimal pH and PaCO2 levels for non-CODP patients.
It is suggested that strict compliance with protocols aimed to regulate patient selection for NIV is a prerequisite of high NIV success rate (10). Moreover, although NIV proved to be as safe as conventional treatment methods or and is characterised with multiple benefits (11) especially for immunocompromised patients associated with high mortality rates due to ETI (12), individual negative attitudes to NIV (e.g., fear and intolerance of NIV) may contribute to NIV failure (13). Thus, the study will aim to determine a scoring model considering objective and subjective data in order to predict failure or success. Additionally, in order to identify the efficacy of NIV in the treatment of different patient populations, two cohorts (CODP and non-CODP) will be employed in the research. Their exposure to the studied variables and factors will be examined, and then the distribution of outcomes in two samples will be compared.
The second phase of the cohort study will include the evaluation of independent sample. Nevertheless, the realisation of this method will largely depend on the results obtained during the previous stage.
A prospective study in chronic COPD respiratory failure.
Researchers suggest that NIV may increase the respiratory volume and decrease the respiratory rate in patients with COPD and consequently improve gas exchange parameters (14). Considering this, at this stage of research, potential effects of NIV on alveolar ventilation will be analysed by using the physiological and radiological data collected before and after NIV implementation. Through statistical analysis, the results of computed tomography of the chest and NIV’s effects on diaphragmatic function will be converted into quantitative data.
Training Opportunities and Supervision
It is possible to say that high-quality management of the research process is a crucial factor contributing to reliable and valid project outcomes. The collaboration with qualified supervisors on the organisational, theoretical, and practical issues associated with the proposed project will thus help the student to identify possible difficulties in a timely manner and address them accordingly. At the University, such monitoring procedures as regular meetings of supervisors with investigators and researchers’ self-reports are commonly practised. The given supervision activities will help the student to be supported throughout the process of investigation.
To enhance research skills and build competence in methodology, the student will be engaged in self-education and will also attend the programs offered by the University. Modern scientific cognition is defined as a complex process involving exploration, computation, explanation, and prediction activities (15). It means that scientific and scholarly research processes are highly differentiated. However, research methods cannot be regarded as a disparate set of cognitive tools but should be treated as a unified complex of functionally interconnected cognitive processes. Therefore, the understanding of methodology can be highly beneficial in conducting a trustworthy, efficient, and high-quality study. Not only will it help to facilitate the research process, but also will allow improving the results.
Costs
The project costs will include the fees for the purchase of the SPSS software. The investment in the given statistical tool is important as it will allow carrying out a large number of test and analysis procedures aimed to measure different variables and find answers to distinct research questions. Additionally, some expenditures will be associated with learning. Overall, it is expected that the total amount of costs will account for about £2000 excluding PhD fees.
References
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AlYami MA, AlAhmari MD, Alotaibi H, et al. Evaluation of efficacy of non-invasive ventilation in non-COPD and non-trauma patients with acute hypoxemic respiratory failure: a systematic review and meta-analysis. Ann Thorac Med 2015;10:16-24.
Hodgson LE, Murphy PB. Update on clinical trials in homeventilation. J Thorac Dis. 2016.
Brochard L, Isabey D, Piquet J, et al. Reversal of acute exacerbations of chronic obstructive lung disease by inspiratory assistance with a face mask. N Engl J Med. 1990;323(22):1523-30.
Nava S, Ergan, B. Long-term non-invasive ventilation (NIV) for COPD patients with chronic respiratory failure. EMJ Respir. 2013;1:54-62.
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Gopalakrishnan S, Ganeshkumar P. Systematic reviews and meta-analysis: understanding the best evidence in primary healthcare. J Family Med and Prim Care. 2013;2(1):9-14.
Budweiser S, Jörres RA, Pfeifer M. Treatment of respiratory failure in COPD. Int J Chron Obstruct Pulmon Dis. 2008;3(4):605-618.
Bersten AD. Best practices for noninvasive ventilation. CMAJ. 2011;183(3):293-294.
Nicolini A, Piroddi IM, Barlascini C, Senarega R. Predictors of non-invasive ventilation failure in severe respiratory failure due to community acquired pneumonia. Tanaffos. 2014;13(4):20-28.
Zhu G, Huang Y, Wei D, Shi Y. Efficacy and safety of noninvasive ventilation in patients after cardiothoracic surgery: a PRISMA-compliant systematic review and meta-analysis. Dalar. L, ed. Medicine. 2016;95(38):e4734.
Huang HB, Xu B, Liu G-Y, Lin J-D, Du B. Use of noninvasive ventilation in immunocompromised patients with acute respiratory failure: a systematic review and meta-analysis. Critical Care. 2017;21:4.
Ngandu H, Gale N, Hopkinson JB. Experiences of noninvasive ventilation in adults with hypercapnic respiratory failure: a review of evidence. Eur Respir Rev; 25: 451–471.
Bräunlich J, Köhler M, Wirtz H. Nasal highflow improves ventilation in patients with COPD. IntJ Chron Obstruct Pulmon Dis. 2016;11:1077-1085.
Bonawitz, ER, The rational child: theories and evidence in prediction, exploration, and explanation [doctoral thesis]. [Massachusetts (US)]: B.S., Northeastern University; 2009.