After major surgery, the complication that is most common and also most easily overlooked is not wound infection. It is the lungs, which are affected by anaesthesia, lying in bed and pain from the wound. Anaesthetic drugs weaken the movement of the diaphragm and make breathing shallow. Patients are also often afraid to breathe deeply or cough hard because of wound pain, so secretions collect in the airways and some of the air sacs collapse, causing atelectasis (collapsed lung). Once the collapsed area of lung collects sputum and is poorly ventilated, it can easily worsen into pneumonia after surgery. These two complications not only lengthen the hospital stay but also raise the risk of death, and are a particular threat to older people having upper abdominal and chest surgery.
The good news is that lung complications can be prevented, and the most convincing medical evidence points to preparation before surgery. A randomised controlled trial showed that when a physiotherapist taught one session of deep breathing and coughing techniques before surgery, lung complications after surgery were reduced by half in relative terms (Boden et al. 2018). This article first uses the ARISCAT risk model to show which patients are at high risk, then explains why the evidence for the three-ball breathing device alone is weak, and finally describes the combination that has evidence behind it.
Assessing risk: the seven ARISCAT risk factors
To prevent effectively, risk must first be identified. To assess which patients are more likely to have lung complications after surgery, clinicians often use the ARISCAT model, which was derived from large surgical cohort studies. The model lists seven independent risk factors, and the more of them a patient has, the higher the risk (Canet et al. 2010). The assessment is not meant to cause alarm. It helps the family understand the situation, and if the patient meets several of the indicators, preparation before surgery is all the more worthwhile.
- Older age
- Low oxygen saturation (SpO₂) before surgery
- A respiratory infection within the past month
- Anaemia before surgery
- A surgical incision in the upper abdomen or chest
- Surgery lasting more than two hours
- Emergency (unscheduled) surgery
Items such as an upper abdominal or chest incision and the length of the operation are set by the surgery itself and cannot be changed. However, oxygen saturation before surgery, anaemia, a recent respiratory infection and the patient’s fitness are the key points that may be improved before surgery. This is the starting point of prehabilitation before surgery.
Clinical research: the effect of one session of physiotherapy teaching before surgery
Among the single measures to prevent pneumonia after surgery, the most effective step comes not after surgery but before it. The LIPPSMAck-POP randomised controlled trial recruited patients about to have major upper abdominal surgery and gave them one educational session from a physiotherapist before surgery, covering deep breathing exercises, an effective way to cough up sputum and an explanation of why early activity matters. The results showed that lung complications after surgery were halved in relative terms (adjusted risk ratio 0.48), with a number needed to treat (NNT) of only 7, which means that for every seven patients taught, one was spared a lung complication (Boden et al. 2018).
This study shows that the way to prevent lung complications is in fact simple and low in cost. The patient does not need expensive equipment. One session of teaching before surgery is enough to halve the risk of complications. Home physiotherapy can use the same approach, teaching the patient at home before the operation to make sure the patient really learns how to do the breathing exercises alone.
Another direction for preparation before surgery is inspiratory muscle training (IMT), which uses a resistance device to train the breathing muscles. A Cochrane systematic review combined data from patients having cardiac and major abdominal surgery and found that IMT before surgery lowered the risk of atelectasis (RR 0.53) and pneumonia (RR 0.45), and also shortened hospital stay (by 1.33 days on average) (Katsura et al. 2015). The conclusions of the two studies before surgery point in the same direction: bringing prevention forward to before the operation gives the most marked benefit.
The limits of the research on an incentive spirometer used alone
On preventing pneumonia after surgery, many patients think first of the three-ball breathing device handed out on the ward (the incentive spirometer), where the patient breathes in hard to lift three small balls. As a visual prompt for deep breathing the device does have a use, but the current medical evidence does not support the idea that diligent practice of breathing in alone prevents pneumonia.
A Cochrane systematic review specifically examined how well using an incentive spirometer alone after upper abdominal surgery prevents lung complications. It concluded that the evidence is insufficient and does not support it as a routine stand-alone measure (do Nascimento Junior et al. 2014). The problem is not that the device is harmful. A supportive tool should not be taken as a complete prevention plan. What has real evidence behind it is a combination of measures and not a single movement or piece of equipment.
Setting the three sets of data side by side, the conclusion is quite clear: what really brings down the risk is intervention before surgery (including education and inspiratory muscle training), and not a breathing device alone after surgery. An incentive spirometer can serve as a prompt within the prevention combination, but it should never be the only line of defence.
The combination for preventing lung complications: deep breathing, coughing and early activity
Putting the medical evidence into everyday care, preventing lung complications after surgery needs three things to be done together, and none can be left out.
Among these three, coughing is often where things get stuck. When the sputum is plentiful and sticky and the wound is painful, an older person often cannot bring the sputum up even with verbal reminders from the family. If deep breathing and ordinary coughing do not clear the secretions, a physiotherapist needs to step in with professional airway clearance techniques. If the patient is stuck at the stage of having sputum but being unable to cough it up, see the article on clearing airway secretions (airway clearance) for the special techniques involved.
What the family can help with in the first few days after surgery
- Remind the patient to do several sets of deep breaths every hour, especially while in bed
- Before the patient coughs, help by pressing a pillow gently against the wound to ease the pulling pain
- With the medical team’s agreement, help the patient to sit up or stand at the bedside
- Watch the colour of the sputum and whether the patient is short of breath or has a fever, and tell the medical staff at once if anything changes
When to contact the medical staff at once
- Fever or chills, or sputum that changes from clear to yellow-green or bloodstained
- Breathing that becomes clearly faster or laboured, or a fall in oxygen saturation
- Chest pain, or difficulty getting breath even when speaking
- Sputum that collects and cannot be coughed up whatever the patient tries, with the chest feeling more and more tight
Division of roles after surgery and when to ask a therapist for help
The line between roles must be drawn clearly here. Physiotherapy is responsible for the mechanical prevention of lung complications, which includes reopening the air sacs, clearing secretions and helping the patient to get moving early. Pneumonia that has been diagnosed needs medical intervention such as antibiotic treatment and oxygen support, which is the doctor’s and the hospital’s area. The two complement each other and do not replace each other. The core value of physiotherapy is to keep the risk down before illness occurs, and to help the patient regain lung function after recovery.
In recent years the length of stay in Hong Kong public hospitals has kept getting shorter, and many older people have to go home before the body has returned to its state before surgery, which leaves a gap with no professional follow-up after discharge. Yet the first one to two weeks after surgery are exactly when lung complications are most likely and when the patient most needs someone closely following breathing practice and activity progress. If care is interrupted after discharge, this line of defence is often lost. For how home rehabilitation after surgery links up closely, go back to the overview of physiotherapy after surgery. For blood clots, another risk that is high after surgery and has related causes, see preventing blood clots (DVT) after surgery.
When should the family ask a therapist for help? If a family member is having major upper abdominal or chest surgery, is older or has a history of lung disease (which means several ARISCAT risk factors apply), or after discharge does not cough strongly enough to clear sputum, breathes shallowly and is much less active than before the operation, the patient should not practise alone with the three-ball device from the ward. Nova Health’s registered physiotherapists can provide physiotherapy at home before surgery or after discharge. The therapist assesses the patient’s breathing function and home environment, teaches deep breathing, coughing while pressing on the wound and safe early activity, and follows up in stages according to the site of surgery, to bring the risk of lung complications down as far as possible.