Michael Patkin's

Postoperative confusion:
A guide to management

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Confusion and agitated behaviour are common complications after operation, especially in elderly patients. It is customary to prescribe sedation, instead of regarding confusion as a symptom whose causes must be , diagnosed, and preferably anticipated and prevented. A simple scheme of management is outlined, with special emphasis on common conditions.

Postoperative confusion is a serious problem of elderly patients in most large hospitals. Often it is a symptom of an acute underlying disorder which needs early treatment. It may in turn cause its own complications, such as injury, disturbance of healing tissues or of equipment, or pneumonia due to mistaken over-use of sedation in treatment. The turmoil caused by a confused patient is distressing to other patients, and creates hard work for nurses and junior medical staff.

The difficulties of postoperative confusion are made worse because the condition is usually managed by the resident staff who are the least experienced, and by night nursing staff in circumstances when bedside examination is awkward and when attendants may be tired after a long working day. Often the patient is new to the duty doctor, and there is a temptation to cut corners. For such reasons it is important to have a plan of management which is simple while being reasonably comprehensive, and which can be followed readily by nursing and junior medical staff.

The stated causes of postoperative confusion have reflected the changing trends in outlook of recent years. Traditionally the blame was put on to old age, which is of course an important element, though younger patients can also be affected. Next it was ascribed to psychological factors of sensory bombardment and deprivation, under influences such as Battle for the Mind, a book by William Sargant which analysed brain-washing. Today the emphasis is, or should be, on a third group of causes whose nature is physical. These causes are made up by clinical, biochemical, and pathological factors. Their accurate diagnosis is an important practical exercise, and a prerequisite for successful management.

The common feature of these factors is interference with cerebral metabolism, whether by altered oxygen levels, altered metabolite concentrations, or by the presence of bacterial toxins. More important than a theoretical analysis is a simple clinical strategy. The usual causes of post operative confusion may be summarized in a single list, with the commonest causes listed in the first of five groups and arranged in a simple anatomical scheme from the head of the patient downwards. Diagnosis, just as in other clinical conditions, rests on the correlation of symptoms, signs, and results of special investigations, with a differential diagnosis of closely related conditions considered and excluded one at a time.

Table of causes

1. Common physical causes, listed from head to toes:

Cerebrovascular disease.
Drugs, delirium tremens.
Chest infection or atelectasis.
Renal infection.
Abdominal sepsis, superficial or deep.
Over-full bladder or rectum.

2. Less common physical causes:

Anaemia (especially vitamin B12 deficiency), unrecognized blood loss, and other forms of anoxia.
Hepatic or renal failure.
Subdural haematoma.

3. Psychological factors:

Sensory distortion by bombardment or deprivation.
Sleep disturbance and loss.
Depression, anxiety, schizophrenia.

4. Aggravation by noxious stimuli:

Fear, discomfort, pain, thirst, hunger.

5. Rare causes:

Hypoglycaemia, fat embolism, hypernatraemia.


Symptoms may be impossible to obtain from a confused patient, but his written history ("data-base") may show evidence of alcoholism and other illness. The medical record may suggest intraabdominal sepsis because of a difficult operative procedure or a long-standing disease that has flared up. The treatment sheet may show sedation by barbiturate, antihistamine, or some other drug known to cause confusion frequently. The fluid balance chart may (or may not) record frequent voiding of small amounts of urine due to chronic retention with overflow, overlooked glycosuria or albuminuria, or spurious diarrhoea caused by faecal impaction. Fever or a raised white cell count may only have been noted that evening.


Physical examination, though complementary to the history, is in this situation more important for diagnosis, and failure to examine the patient leads to mistakes of great danger at times. It is therefore important not to prescribe by telephone for a patient who becomes unexpectedly confused after operation. The detection of physical signs requires the physical presence of the clinician.

Examination starts with careful general observation of those patients at special risk, especially by nursing staff in the late afternoon. This may give early clues before the full picture of confusion and mania develops. Patients with suspected alcoholism, chronic lung disease, or impaired excretion should be viewed for the general signs of a wandering mind such as vagueness, muttering, irregular picking with the hands, and other "inappropriate activity". Simple talking to patients is therefore of double importance; as well as lessening psychological stress for a patient liable to sensory disorientation, it helps in the early diagnosis of confusion.

After some hours the typical picture becomes all too clear. The patient is agitated, calls out, struggles to get out of bed, pulls on tubes connected to him, acts violently to his attendants, whom he may injure, and disturbs other patients who may be far away.

More detailed examination, however difficult at this stage, is important. There may be a hemiparesis, obvious or subtle. Much more often there are signs of a bilateral basal bronchopneumonia, perhaps aggravated by mild cardiac failure, atelectasis, or sputum retention.

Abdominal examination may show one of several groups of causes, comprising renal infection, abdominal sepsis, or retention of urine. The first, renal infection, is rather more common in elderly women who have been confined to bed, and acts both through toxaemia and mild renal failure. The second group, abdominal sepsis, comprises frank peritonitis, local abscess usually pelvic or subphrenic, and wound infection. The third group is retention of urine or faecal impaction. Thus a rectal glove is necessary for the examination to be complete in case of impaction with spurious diarrhoea.

Laboratory Investigations

Special tests may usually be deferred till daylight, except for urine or sputum samples for culture, chest X-ray examinations for uncertain atelectasis, and occasional arterial blood gas analysis. Tests may show unexpected anaemia, an alarming neutrophilia, or evidence of liver or kidney failure.

Often consultation with non-surgical specialists is indicated, perhaps by telephone, and at night. The geriatrician is best able to give advice on the general management of the patient, and indeed should be encouraged to present his aspect of this subject at clinical meetings before individual cases arise. At other times opinions may be sought from general physicians, neurologists, psychiatrists, and specialists in other fields.


Management of the confused postoperative patient may be quite easy or very difficult, depending on the underlying causes of the condition. Most often there is a single predominating factor which is temporary, such as retention of urine, or pneumonia with congestive cardiac failure, to be treated along accepted lines.

Sedative drugs are best withdrawn unless there is uncontrollable agitation, when the most useful are diazepam (Valium), paraldehyde, or chlorpromazine. To combat the effects of the strange hospital environment, geriatricians favour measures such as avoiding darkness in the ward, having a wireless playing where this is practicable, and effective personal contact.

Delirium tremens is a special problem which it is important to anticipate or detect early, when small doses of whisky or brandy can control the condition at the mildest stage. Other methods of treatment used include the B group vitamins, thiamine and pyridoxine, in large doses, and fructose, although the metabolic changes caused by the last substance would be a cause for concern in the immediate postoperative period.

When confusion is found to be due to a leaking bowel anastomosis, the outlook for the patient is poor. The difficult decision should in general be to reoperate, as the peritonitis is more likely to progress than to localize, and delay worsens the prognosis of operative treatment.


With modern techniques in surgery, anaesthesia, and medicine, there is greater scope for surgical treatment of the elderly, and therefore a greater incidence of confusion as a postoperative complication. The management of this condition must be simple and effective. With more interest being taken in the problem of postoperative confusion, it should be less often a hazard to patients, and less of a trial to those about them.


I wish to thank Dr R. Brooks of Whyalla and Dr C. Hughes of the Modbury Hospital, Adelaide, for their helpful criticism, and Dr A. Burrell, a resident at the Royal Newcastle Hospital when I first thought of this paper. Since starting, my aim changed from preparing an academic review to presenting a practical guide to a neglected problem.




Table of causes
Laboratory Investigations

The curious changes in Google ratings:

In July 2009 this was the first paper to be listed if you googled the topic. ("Out of over 1 million"). Three weeks later it wasn't listed. A few days later (August 11) it was the Number 2 rated web page in the topic - despite no changes in the page!


First published as:

Med. J. Aust., 1973, 2: 559-561. Current Practice
Michael Patkin, F.R.A.C.S.*
The Whyalla Hospital
*Honorary surgeon
Address for reprints: Mr. M.Patkin, Brimage House, 20 Brimage Street, Whyalla, SA 5600

Recent articles on the same topic:include a few on confusion after perfosion after open heart surgery.

However the well-known frequent occurrence of confusion, often followed by death, after surgery such as hip replacement, is ignored. Just ask an experienced anaesthetist.