Anaesthesia

CASE 92: FitneSS For Surgery – CarDiaC DiSeaSe

history

At the preoperative assessment clinic, you have been asked to clerk a 76-year-old man for a total hip replacement. He was placed on the waiting list by the consultant 3 months previously. He currently walks with two sticks and is woken at night with pain in his right hip. Since his initial consultation, the patient has had intermittent episodes of chest tightness and dizziness brought on by exertion. The symptoms subside with rest and have been associated with pain in the left arm. He was seen in the emergency department the previous week after an episode of collapse and was told he may have suffered a heart attack. He is now waiting to see his GP for further investigation.

He has no previous history of heart disease and was, up until recently, able to climb the 12 steps to his flat without shortness of breath. He is currently taking aspirin, which was started by the emergency department doctor after his collapse. He does not smoke and has the occasional social drink.

examination

The patient’s blood pressure is 186/106 mmHg and the pulse rate is 84/min. On auscultation, the chest is clear, but there is a systolic murmur over the right sternal edge which radiates into the neck. Examination of the right hip demonstrates limited internal rotation, compared to the left side.

INVESTIGATIONS

Questions

•What concerns do you have about this patient’s fitness for surgery?

•Which investigations should be ordered before proceeding with surgery?

•Do any other specialists need to be consulted about this patient’s care prior to surgery?

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100 Cases in Surgery

ANSWER 92

The patient has clinical evidence of serious cardiac disease and is an extremely high risk for an elective surgical procedure. The patient’s history and examination have highlighted a number of important risk factors:

•Hypertension: he is hypertensive, which is associated with an increased incidence of ischaemia, left ventricular dysfunction, arrhythmia and stroke during the perioperative period. Patients should ideally have a systolic blood pressure of less than 140 mmHg and a diastolic blood pressure of less than 90 mmHg before proceeding with surgery. This patient should be referred back to his GP or to a specialist for antihypertensive medication.

•Ischaemic heart disease: it is important to establish whether this patient did have a heart attack the previous week. An electrocardiogram or a troponin level, taken 12 h after the collapse, may have provided definitive evidence of a myocardial infarct. Patients having an operation within 3 months of a myocardial infarction carry a 30 per cent risk of reinfarction or cardiac death. This drops to 5 per cent after 6 months. The patient also appears to be suffering from angina, which needs further investigation by a cardiologist prior to surgery. Patients with acute coronary syndrome carry a significant risk of perioperative myocardial infarction and may benefit from a revascularisation procedure.

•Aortic stenosis: the systolic murmur radiating to the carotid may be due to aortic stenosis. Aortic stenosis leads to overload of the left ventricle, resulting in ventricular hypertrophy and ultimately dilatation and failure. The severity of the valvular disease can be assessed by echocardiography. The patient may require valve replacement prior to hip replacement if there is evidence of a tight stenosis of the aortic valve. If left undiagnosed, it is associated with a tenfold increase in perioperative death. This patient’s high blood pressure makes a significant stenosis unlikely.

KEY POINT

•patients having an operation within 3 months of a myocardial infarction carry a 30 per cent risk of reinfarction.

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Anaesthesia

CASE 93: FitneSS For Surgery – reSpiratory aSSeSSment

history

You are the doctor in the surgical pre-assessment clinic. Your first patient is a 66-year-old man who is being admitted for an elective abdomino-perineal resection for rectal carcinoma. He suffers with chronic obstructive pulmonary disease (COPD) and is a smoker of 15 cigarettes a day. Apart from mild hypertension there is no evidence of cardiac disease. He uses inhalers daily and takes oral theophyhlline and amlodopine. His exercise tolerance is 30 yards and he has had two previous admissions to hospital with breathing problems. He has never required admission to an intensive care unit. He does not require home oxygen at present. His father died of lung cancer. He currently lives alone.

examination

His blood pressure is 146/92 mmHg, pulse rate 88/min and oxygen saturations are 93 per cent on air. The heart sounds are normal. On auscultation of the chest there is moderate air entry with some scattered wheeze. The rest of the examination is unremarkable.

Questions

•What tests would you consider organizing in addition to routine bloods and an electrocardiogram?

•What are the potential problems that patients with significant COPD face in the postoperative period?

•What advice would you give him regarding his smoking habit prior to his surgery?

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100 Cases in Surgery

ANSWER 93

This patient will need an up-to-date chest x-ray, a baseline arterial blood gas and some basic respiratory function tests, such as spirometry. Spirometry is a timed measurement of dynamic lung volumes during forced expiration, used to quantify lung capacity and determine how quickly the lungs can be emptied. The measurements usually taken are the forced vital capacity, forced expiratory volume in 1 second, and the ratio of these two volumes (FEV1/FVC). A ratio of <70 per cent indicates an obstructive ventilatory defect, such as COPD. Patients with restrictive airways disease, such as interstitial lung disease or kyphoscoliosis, have smaller volumes and tend to have a ratio of >80 per cent.

Patients with COPD have difficulty clearing secretions from the lungs during the postoperative period. They also have a higher risk of basal atelectasis and are more prone to chest infections. These factors in combination with postoperative pain (especially in thoracic or abdominal major surgery) make them prone to respiratory complications. Consultation with a chest physiotherapist both prior to surgery, to teach breathing exercises, and in the postoperative period in order to optimize respiratory function is essential. Adequate analgesia is essential postoperatively and often requires the use of an epidural. Patients should also be taught how to hold their incisions to prevent pain when taking deep breaths or coughing.

Summary of complications more common in those with preoperative respiratory disease

•Atelectasis

•Bronchospasm

•Chest infection

•Hypoxia

•Pulmonary embolism

•Respiratory failure

Every effort must be made to persuade patients who smoke to give up prior to surgery. Those with lung disease will benefit if this is done at least 6 weeks before an operation. There is a reduction in mucus hypersecretion, small-airway narrowing and an improvement in tra- cheo-bronchial clearance of secretions. Patients with cardiac disease should also be encouraged to stop smoking prior to surgery. The increased carbon monoxide levels and the effects of nicotine (increased heart rate and systemic blood pressure) lead to an increase in cardiac stress during surgery. This can be significantly improved if smoking is stopped 24 h prior to surgery, due to the short half-lives of nicotine and carbon monoxide.

KEY POINTS

•patients with CopD are more prone to basal atelectasis and chest infections.

•patients should be encouraged to give up smoking at least 6 weeks prior to surgery.

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