Review An update on contraindications for lung Thorax: first published as 10.1136/thx.2010.139881 on 29 July 2010. Downloaded from function testing Brendan G Cooper Correspondence to ABSTRACT medicine, this is a timely and worthwhile review Brendan G Cooper, Lung Guidelines on contraindications for lung function tests that needs wide dissemination and discussion in Investigation Unit, University > order to formulate new guidelines. Hospitals Birmingham NHS have been based on expert opinion from 30 years ago. Foundation Trust, Edgbaston, High-risk contraindications to lung function testing are Contraindications generally fall under the Birmingham B10 2TH, UK; associated with cardiovascular complications such as umbrella of risk management and clinical gover- [email protected] myocardial infarct, pulmonary embolism or ascending nance issues in most health centres. Risk manage- aortic aneurysm. Slightly less risky but still serious ment is made up of two components (1) the Received 31 March 2010 Accepted 11 May 2010 contraindications are predominantly centred on recovery likelihood of the event happening and (2) the Published Online First from major thoracic, abdominal or head surgery. Less severity of the consequences for the patient if it 29 July 2010 serious surgical procedures will present a possible risk, happens. In most areas of respiratory physiology but the RR depends upon whether the lung function is testing, the likelihood of an adverse event is very essential or can wait until the patient’s condition low and many often have relatively minor (non- improves. In recent decades there have been moves life-threatening) consequences (eg, cataract towards less invasive surgical techniques, keyhole detachment during spirometry). Even the more surgery and new technology such as laser surgery which serious surgical complications such as rupture of an minimise the amount of collateral damage to surrounding aortic aneurysm which has an absolute prevalence tissues. In thoracic surgery there is a shift in emphasis to of only 7.1% in men and 1.6% in women8 are quicker postsurgical mobility. Furthermore there has relatively rare, so the likelihood of these happening been little analysis of the scientific facts behind the during spirometry is very rare. Postponed lung current recommendations and contraindications. The function testing due to current contraindications in principle absolute and relative contraindications are in our experience is only w0.3e0.5% (personal need of revision, and recommended times of abstaining communication, ARTP website Forum 2009). A from lung function tests needs to be reviewed. This suggested table of relative risks appears in review aims to outline the key issues and suggests appendix 1. newer recommendations for contraindications for Contraindications can be considered as being http://thorax.bmj.com/ performing lung function using a risk matrix, as well as ‘relative’ or ‘absolute’. Most contraindications are offering alternative approaches to testing patients who relative and require the requesting physician/ may be at risk of complication from testing. In general, healthcare expert to judge when it is safe and the previous recommendation of waiting for 6 weeks appropriate to undertake the breathing test. Abso- after surgical procedures or medical complications before lute contraindications are those that would cause performing lung function can often now be reduced to trauma, injury or death to the patient if they were <3 weeks with modern less invasive surgical undertaken. Sometimes the contraindication just techniques. means that the test is unnecessary or unlikely to be on September 24, 2021 by guest. Protected copyright. of real clinical benefit to a compromised patient, and a lung function test would be better when they are remote from surgery or infection. Similarly, INTRODUCTION a dogmatic approach of refusal to test patients with As lung function testing, and particularly spirom- any contraindication needs to be tempered. etry, becomes more widespread across primary and The main principle of performing lung function secondary, care there are greater numbers of prac- tests is that the risks of the procedure will provide information that will be outweighed by the benefit titioners and commissioners who are unaware of ’ the potential harm and discomfort that these tests the patient s assessment for operation or treatment provides. If the reverse is true and the lung function can cause to some patients. International guidelines fi on contraindications for lung function tests1 have test does not entail any bene t for the level of risk been cited by many sources23but their evidence sustained, then the test should not be undertaken. base is generally from the USA and is founded only Close liaison between surgical staff, medical staff e on expert opinion which is now >30 years old.4 7 and healthcare scientists/technologists in lung Recent developments in surgical practice and function should eradicate most unnecessary risk to technology have decreased the invasive nature of patients. procedures, so some of the contraindications may The key relative contraindications cited by the fi 1996 American Association for Respiratory Care now need modi cation. 1 This paper aims to review the evidence base for (AARC) documents are: these contraindications and, where it is lacking, < Haemoptysis of unknown origin (forced expira- examine the known facts around the potential tory manoeuvre may aggravate the underlying problems in order to suggest new recommenda- condition); tions. In the current culture of evidence-based < Pneumothorax; 714 Thorax 2011;66:714e723. doi:10.1136/thx.2010.139881 Review < Unstable cardiovascular status (forced expiratory manoeuvre Excellennce (NICE) has published general recommendations on Thorax: first published as 10.1136/thx.2010.139881 on 29 July 2010. Downloaded from may worsen angina or cause changes in blood pressure) or surgical site infection and healing (http://www.nice.org.uk/ ‘recent’ myocardial infarction or pulmonary embolus; nicemedia/pdf/CG74NICEGuideline.pdf). < Thoracic, abdominal or cerebral aneurysms (danger of rupture ‘Healing time’ is a general term and may refer to functional due to increased thoracic pressure); healing rather than tissue repair, and does not of course mean < ‘Recent’ eye surgery (eg, cataract); that patients could not perform lung function tests before this < Presence of an acute illness or symptom that might interfere time. The time taken before maximal manouevres would cause with test performance (eg, nausea, vomiting); and damage to the surgical area (eg, rupture stitches, etc.) or pain to < Recent thoracic or abdominal surgery. the patient needs to be considered. Also, there are a number of These recommendations are based on very little concrete risk factors which prolong healing, including smoking, diabetes, e e evidence.4 7 and to date there have been no randomised age, poor nutritional status and general health.11 13 controlled trials (RCTs) published in this area. Each of these key Surgical procedures that could be affected by lung function issues will be reviewed in this paper and, where possible, new testing include the following categories: recommendations will be suggested. < Abdominal surgery. < Eye surgery. POTENTIAL HARM FROM LUNG FUNCTION TESTS < Thoracic surgery. The most likely harm from lung function testing originates < Ear surgery. probably from four key factors: < Brain surgery. 1. Maximal pressures generated in the thorax and their impact on abdominal and thoracic organs/tissues. ABDOMINAL SURGERY 2. Large swings in blood pressure causing stresses on tissues in Generally, the more muscular damage involved in abdominal the body (head, limbs, etc.). surgery, the longer the time for healing is required. 3. Expansion of the chest wall and lungs. 4. Active communicable diseases (tuberculosis (TB), hepatitis B, Laparotomy HIV, etc.). Laparotomy for abdominal surgery is increasingly being reduced It is worth noting that postoperative physiotherapy including by using laparoscopy involving ‘keyhole’ techniques. A recent encouraging deep breathing, coughing and incentive spirometry Cochrane review14 has shown that people who have keyhole after thoracic surgery is actually thought to be beneficial in procedures can return to their normal daily activities on average terms of reversing atelectasis, thus reducing the risk of pneu- 3e4 days earlier than those who have open surgery. One study monia.8 9 Similarly in cardiothoracic surgery the emphasis is on gastric bypass surgery comparing laparoscopic with conven- now shifting towards earlier mobilisation of the patient post- tional surgery15 has shown that lung function (forced expiratory operatively in order to re-establish normal respiration rather volume in 1 s (FEV1)) falls to 40% of the preoperative value on 910 than a policy of avoiding activity. the first postoperative day, 50% by day 3 and 80% by day 7. By http://thorax.bmj.com/ Many contraindications have a higher risk, with the more day 7 there was no difference in lung function after either volitional tests involving forced manoeuvres such as spirometry, surgical technique. This suggests that meaningful spirometry maximum mouth pressures and possibly full exercise tests. can be performed if required within 1 week of abdominal surgery However, considerable information can be gained from less by either technique. forced tests such as oscillometry, relaxed vital capacity, static lung volume assessment, gas transfer and some