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Key messages
1. Patients with obstructive sleep apnoea may at higher risk of complications after some
types of surgery (Q).
2. Patients with obstructive sleep apnoea have an including an increased risk of obstructive
episodes and desaturations (N) (Level III‐2).
3. Morbidly obese patients undergoing bariatric surgery may be at increased risk of
postoperative hypoxaemia independent of a diagnosis of obstructive sleep apnoea (N)
(Level III‐2).
4. Continuous positive airway pressure does not increase the risk of anastomotic leak after
upper gastrointestinal surgery (U) (Level III‐2).
The following tick box represents conclusions based on clinical experience and expert
opinion.
Management strategies that may increase the efficacy and safety of pain relief in patients
with obstructive sleep apnoea include the provision of appropriate multimodal opioid‐
sparing analgesia, continuous positive airway pressure, monitoring and supervision (in a
high‐dependency area if necessary) and supplemental oxygen (U).
11.6 THE PATIENT WITH CONCURRENT HEPATIC OR
RENAL DISEASE
The clinical efficacy of most analgesic drugs is altered by impaired renal or hepatic function,
not simply because of altered clearance of the parent drug, but also through accumulation of
toxic or therapeutically active metabolites. Some analgesic agents can aggravate pre‐existing
renal and hepatic disease, causing direct damage and thus altering their metabolism.
A brief summary of the effects that renal or hepatic disease may have on some of the drugs
used in pain management, as well as alterations that might be required in analgesic drug
regimens, is given in Tables 11.5 and 11.6.
11.6.1 Patients with renal disease
The degree to which analgesic drug regimens require alteration in patients with renal
impairment depends largely on whether the drug has active metabolites that are dependent
CHAPTER 11 on the kidney for excretion or if the drug may further impair renal function.
There is some limited information about the ability of dialysis to clear the drugs and/or their
metabolites. Molecules are more likely to be removed by dialysis if they have a low molecular
weight, greater water solubility and lower volume of distribution; a higher degree of protein
binding and use of lower‐efficiency dialysis techniques will reduce removal (Dean, 2004).
The available data indicates the following (see Table 11.5 for references).
• Analgesics that exhibit the safest pharmacological profile in patients with renal
impairment are alfentanil, buprenorphine, fentanyl, ketamine, paracetamol (except with
compound analgesics) and sufentanil. None of these drugs delivers a high active
metabolite load or has a significantly prolonged clearance.
• Oxycodone can usually be used without any dose adjustment in patients with renal
impairment. Its metabolites do not appear to contribute to any clinical effect in patients
with normal renal function.
414 Acute Pain Management: Scientific Evidence
