Description of the condition
Lung cancer is the most common malignant tumour and accounted for 1.37 million deaths worldwide in 2008 according to World Health Organization (WHO). It is one of the malignant tumours that causes most deaths in the world, being the second most common cancer in men, after prostate, and in women, after breast cancer. In about 87% of cases, smoking is related to the diagnosis and proves to be the main risk factor for disease development. Other risk factors are exposure to ultraviolet and ionising radiation, random gas and asbestos; viral infection and genetic factors (Ferlay 2010; Jemal 2011; NICE 2011).
Symptoms such as haemoptysis, cough, shortness breathing or dyspnoea, chest pain, hoarseness, weight loss, and finger clubbing can be often observed as clinical manifestations and an X-ray or chest computed tomography should be performed. If there is an image suggestive of lung cancer, the patient should be referred promptly to a specialist and more specific tests will be required in order to confirm the diagnosis, identify the type of cancer and the stage of the lesion (Rivera 2007).
There are several different types of lung cancer, but it is usually classified into two major groups: non-small-cell lung carcinoma (NSCLC) and small-cell lung carcinoma (SCLC). The most common treatment with curative intent for NSCLC is surgery. It is indicated for patients with stages I and II disease who are fit to tolerate surgery. An overall risk score, such as Thoracoscore, is used in order to estimate the risk of operative death. The treatment of choice is lobectomy (either open or thoracoscopic) (NICE 2011).
Factors such as the duration of surgery, duration of anaesthesia and mechanical ventilation may contribute to postoperative morbidity and mortality. The type and extent of surgery can reduce these complications. For example video-assisted thoracic surgery is less invasive than open thoracotomy and may result in fewer complications. One retrospective descriptive study conducted at the Siriraj University Hospital, Thailand, between 2006 and 2010 studied 512 patients. The objective was to determine the morbidity and mortality in pulmonary resection surgery using clinical data. About 70% of all patients underwent pulmonary resection for lung cancer and 39.5% experienced morbidity or mortality (Igai 2009; Kutlu 2000; Suksompong 2012).
Mortality and morbidity after lung resection are usually caused by complications during the postoperative period often related to pulmonary complications, such as acute lung injury, acute respiratory distress syndrome and pneumonia. To minimise these postoperative respiratory complications, some authors recommend the use of non-invasive positive pressure ventilation (NIPPV). Using this support may help to expand the lungs, prevent atelectasis, prevent hypoxaemia, and mobilise intrapulmonary secretions thus preventing their accumulation and resultant pneumonia (Brooks-Brunn 1995; Kutlu 2000; Lorut 2005; Perrin 2007).
Description of the intervention
NIPPV can be defined as a technique that provides pressurised gas to the airway, promoting increased transpulmonary pressure, inflating the lungs through a mask or interface, and which does not use an invasive route (e.g. endotracheal tube, oronasal tube or tracheostomy). Physiologically, this technique promotes an increase in functional residual capacity and recruitment of collapsed airways, providing better oxygenation, reducing carbon dioxide (CO2) retention and decreasing the work of breathing (Brochard 2002; Schettino 2007).
There are two types of NIPPV: continuous positive airway pressure (CPAP), where only one pressure level is employed at end-expiration, and bi-level positive airway pressure, which employs two pressure levels (inspiration/end-expiration). The main difference is that the bi-level type can increase the tidal volume and may help during the inspiratory phase (Vital 2008; Schettino 2007).
Some studies have shown benefits from the use of NIPPV in the treatment of acute respiratory failure, the most common postoperative complication following abdominal or thoracic surgery. Other complications which may be avoided by the use of NIPPV include hypercapnia, hypoxaemia, atelectasis, pleural fistula and respiratory muscle dysfunction. (Martin 2000; Auriant 2001).
Published clinical trials have demonstrated that the use of NIPPV can reduce the number of pulmonary complications and mortality. This makes it possible to reduce the length of hospital stay and hospital costs (Nakagawa 2001; Arozullah 2003; Lorut 2005).
How the intervention might work
The use of NIPPV (CPAP or bi-level) promotes increased lung volumes because of recruitment of collapsed airways, leading to a better oxygenation of tissues and increased lung capacity. Atelectasis, lung infections, bronchial congestion and consequent acute respiratory failure can be prevented (Brochard 2002).
Therefore, the intervention aims to minimise the risk of complications, reduce the length of hospital stay and the need for re-intubation.
Why it is important to do this review
In recent years trials have been published focusing on this intervention and therefore it seems to be relevant to objectively review the results.