ANAESTHESIA
CASE 90: Day CaSe Surgery
history
A 56-year-old man has been referred to the surgical outpatient department with a right-sided inguinal hernia. He has requested a day surgical procedure. The patient has type 2 diabetes and hypertension. He has no history of a myocardial infarction or angina. He lives in a house with ten stairs, which he can climb easily without shortness of breath. He takes metformin 500 mg tds for his diabetes and atenolol 50 mg daily for his hypertension. He is a non-smoker and drinks fewer than 12 units of alcohol per week. He lives with his wife, who is fit and independent.
examination
His blood pressure is 130/80 mmHg and the pulse rate is 88/min. His body mass index (BMI) is 28 and a random blood sugar is 6 mmol/L. The chest is clear and heart sounds are normal. Abdominal examination reveals an easily reducible non-tender right inguinal hernia.
Questions
•Which factors are important in patients being considered for day surgery?
•What is the patient’s ASA (American Society of Anaesthesiologists) status?
•Why are the patient’s social circumstances important?
•What would you advise about the metformin prior to surgery?
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100 Cases in Surgery
ANSWER 90
The criteria for day surgery selection are based on published guidelines and recommendations, which vary between hospital trusts. The surgical procedure should have an estimated operation time of less than 1 h with minimal expected blood loss. Operations that lead to severe postoperative pain or nausea are not suitable as day cases. Operations that lead to a loss of independence or toilet function are also unsuitable. The risk of complications should be minimized with the aim to prevent an inpatient stay. To determine a patient’s fitness for surgery, the anaesthetists grade physical status using the ASA classification:
•Class 1: patients with no organic, physiological, biochemical or psychiatric disturbance
•Class 2: patients with mild systemic disease but no functional limitations, e.g. controlled diabetes or hypertension
•Class 3: patients with moderate systemic disease and functional limitations
•Class 4: severe systemic disease which is a constant threat to life
•Class 5: moribund patient, not expected to survive 24 h
Patients should ideally be ASA 1 or 2, but some units will accept ASA 3, depending on the disease. This particular patient has an ASA of 2, as he has well-controlled systemic disease with no functional limitations. There is no absolute restriction on age, as the selection is mainly based on physical status. A patient should be able to climb a flight of stairs and should ideally have a BMI <35. Patients with uncontrolled hypertension, epilepsy, cardiac failure or severe gastric reflux are usually considered unsuitable.
Social criteria must also be met before patients can attend day surgery:
•The patient should be accompanied for the first 24–48 h after surgery.
•An escort should be available to take the patient home.
•The patient or caregiver must have access to a private telephone.
•The travel time to home must not exceed 1.5 h.
Metformin should be stopped for up to 48 h prior to surgery. Lactic acidosis is a rare, serious metabolic complication that can occur from metformin accumulation, especially in patients with renal failure.
KEY POINTS
•the aSa system is used to grade a patient’s fitness for surgery.
•patients should be formally assessed for their suitability for day surgery.
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Anaesthesia
CASE 91: antiCoagulation
history
A 64-year-old woman attending the surgical pre-admission clinic is due to be admitted in 2 weeks’ time for an incisional hernia repair. She is known to have atrial fibrillation and is on warfarin. She has also had a recent exacerbation of her chronic obstructive airways disease for which the general practitioner (GP) has prescribed antibiotics and a 1-week course of prednisolone (30 mg od). The treatment is due to be completed in 2 days, and the anaesthetist has already seen her to organize further respiratory investigations.
examination
She is a thin woman with a previous midline laparotomy scar. Her chest is clear and the heart sounds are normal. Examination of the abdomen confirms a large midline defect in the abdominal wall. The hernia is easily reducible and non-tender.
Questions
•How should the anticoagulation be managed prior to surgery?
•Is the recent course of steroids relevant?
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100 Cases in Surgery
ANSWER 91
It is important to determine the patient’s risk of thromboembolic disease before discontinuing anticoagulation. Patients with a low risk of thrombosis should have their warfarin discontinued 4–5 days before surgery. Warfarin should be restarted at the preoperative dose at a safe interval after the procedure, depending on the operation. Patients with prosthetic valves, atrial fibrillation + mitral valve disease, and patients with a history of thromboembolism are considered at high risk of further thrombosis. These patients should be treated with either low-molecular-weight or unfractionated heparin for the duration of time warfarin is withheld. Heparin should be discontinued immediately prior to surgery and restarted postoperatively. The heparin should be continued until the warfarin has been restarted and reached its therapeutic level.
This patient has atrial fibrillation with no other risk factors or previous history of thromboembolism, so is considered to be low risk for thrombosis. It is also important to ask if a patient is on any other medication that may affect coagulation. The following agents should be stopped at the given time prior to surgery:
•Clopidogrel: 7 days
•Ibuprofen: 2 days
•Cilostazol: 5 days
Aspirin should be stopped 7 days prior to surgery, but is now often continued in patients with known cardiovascular disease.
In a normal individual, there is a daily secretion of cortisol, which increases in response to illness or surgery. Patients on regular steroids have a suppressed hypothalamo-pituitary- adrenal axis, which leads to an impaired stress response. This can lead to hypotension and cardiovascular compromise after major surgery. The following patients should be considered for steroid replacement when undergoing a surgical procedure:
•Patients on long-term corticosteroids at a dose of more than 10 mg prednisolone daily (or equivalent)
•Patients who have received corticosteroids at a dose of more than 10 mg daily, in the past 3 months (the patient in this question will, therefore, require steroid replacement therapy)
•Patients taking high-dose inhalation corticosteroids (e.g. beclometasone 1.5 mg a day).
Patients having a minor procedure, such as an inguinal hernia repair, require a bolus of hydrocortisone at induction. Patients admitted for a moderate procedure, such as laparoscopic cholecystectomy, require additional 8-hourly doses of hydrocortisone for 24–48 h postoperatively. Patients for a major procedure require intravenous steroids for at least 2 days postoperatively.
KEY POINTS
•anticoagulation should be stopped prior to surgery.
•patients on steroids may require steroid replacement perioperatively and postoperatively.
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