Box 1-Top tips Back pain and collapse, especially in a man aged over 65 years, mean a diagnosis of ruptured abdominal aortic aneurysm until proved otherwise Never forget to measure serum concentrations of amylase Do not be surprised at the high fluid requirements of patients with perforated viscus or acute pancreatitis. Monitor fluid balance by the trend in vital signs, urine output, and central venous pressure All these diagnoses are serious. Call for help early

Immediate management

Call for immediate senior surgical and anaesthetic help. Even if you are unsure about the diagnosis, this patient is obviously ill and you will need help.

Give the patient 100% oxygen and instruct someone to call the theatre and warn them that a patient with a ruptured abdominal aortic aneurysm is waiting in accident and emergency.

Insert two grey or brown cannulae into the antecubital fossa and withdraw blood for an urgent full blood count, measure urea and electrolytes, clotting and cross match 10 units (measure the concentration of amylase if there is any doubt over the diagnosis). If there is any problem with the cross match you can use grouped non-cross matched or even O rhesus negative blood until cross matched blood arrives.

Fluid replacement is not a straight-forward affair. The temptation is to squeeze litres of fluid or blood into the patient. Although this is appropriate for a patient who has had a cardiac arrest or has an unrecordable blood pressure, a patient with low but stable blood pressure should not be given fluid too quickly. This is because the leak from their aorta driven by a low blood pressure may have been tamponaded by retroperitoneal clot. By forcing intravenous fluids, the patient's blood pressure may rise to overcome the tamponading effect, and haemorrhage may result. Aim for a systolic blood pressure of around 100 mm Hg.

Give opiate analgesia.

Get an electrocardiogram. This will help to exclude myocardial infarction as the diagnosis and act as a baseline, since these patients are at risk of developing perioperative myocardial infarction.

Palpate and record distal pulses. If the patient has an aneurysm this helps confirm your diagnosis. An absence of a pulse may be due to hypotension, but if one is present this is important to know because a later absence, after the operation, suggests occlusion and may make it necessary to return the patient to the theatre.

Do not waste time measuring arterial blood gases.

At this stage there will probably be lots of people around, and you may be able to spend a useful couple of minutes with the relatives - firstly, to explain what is happening as this is very frightening for all concerned, and, secondly, to establish if the patient had any important medical history that might make an operation with a death rate of 50% an undesirable option. In the frantic rush resulting from finding a ruptured abdominal aortic aneurysm, a patient's history of pancreatic cancer diagnosed six months ago may not come out.

Transfer the patient to the theatre as soon as possible to continue resuscitation.

Perforated viscus

A patient with perforated viscus looks unwell. S/he will frequently have generalised peritonitis, with "board-like rigidity" on palpation of the abdomen. The most common organs to perforate are the appendix, stomach, duodenum, and colon (possible causes are diverticular disease or carcinoma). The organ that is responsible may be indicated by the original site of the pain and the age of the patient. The management for all three is similar, with resuscitation followed by laparotomy.

 

Free air under the diaphragm means a perforated viscus (BRUCE P BROWN, MD/VIRTUAL HOSPITAL)

Immediate management

These patients are ill, but you should, with a little, experience be able to manage the initial stages. If you start feeling out of your depth, however, you probably are - so call for help, learn, and treat the next patient using your increased knowledge.

The serious problems with perforated viscus are hypovolaemia, secondary to peritoneal exudate, and sepsis.

Establish intravenous access and take blood samples. Remember, measuring serum concentrations of amylase is essential in all patients with abdominal pain.

Start giving intravenous fluids. In a healthy young patient these can be given rapidly. One unit of colloid immediately, followed by 1 litre bags of crystalloid over one, two, then four hours, is a reasonable starting point, although this can be adjusted according to response (pulse, blood pressure, jugular vein pulse, and urine output). In an elderly patient a central line monitoring the central venous pressure helps assess the fluid balance.

Antibiotics are essential - cefuroxime (or erythromycin if the patient is known to be allergic) and metronidazole.

Give opiate analgesia.

Insert (or better still get someone else to insert) a nasogastric tube; leave it on free drainage with half hourly aspirations.

Insert a urinary catheter, attached to an hourly measuring bag. If you have not already done so send off urine to measure urgently the concentration of é human chorionic gonadotrophin in all women of childbearing age.

Reassess the situation if the patient is stable or improving, then get an erect chest x ray film as this may clinch the diagnosis. If the result is negative but you believe, on the basis of your clinical knowledge, that the patient has a perforation, ask for a lateral decubitus film (an x ray film of the patient lying sideways). You may end up looking very slick.

By now you should have the amylase result back. A small increase may occur in perforation (up to about 200 Somogyi units). If the concentration is much higher, reconsider whether your diagnosis should be one of pancreatitis.

If free air (usually subdiaphragmatic on an erect chest x ray film) confirms the diagnosis the patient will need surgery; prepare for this by contacting the operating theatre and the anaesthetist on call, and obtain patient consent.

Acute pancreatitis

Acute pancreatitis presents in a similar fashion to the other serious causes of acute abdominal pain. The patient will have fairly rapid onset of severe upper abdominal pain radiating to the back. When first assessing the patient you should follow the general guidelines above, and initially the general management is the same as for perforated viscus. Measuring serum amylase will show very elevated concentrations and secure the diagnosis. Having made the diagnosis you may feel you can relax a little. Don't - pancreatitis is a killer with an overall mortality of around 10%.

Immediate management

The main treatment is supportive, resting the pancreas.

You need to assess the severity of the attack. The following investigations should be performed as a minimum if they have not been done already: full blood count, measuring concentrations of urea and electrolytes, amylase, glucose, and arterial blood gases, liver function tests, measuring serum concentrations of calcium and phosphate, and C reactive protein. (Changes in the concentrations of C reactive protein are an indicator of the likelihood of necrosis.) When you have the results of these initial investigations you can begin to determine the severity of the attack (see box 2).

 

Box 2-Severe pancreatitis is defined as the presence of three or more of the following criteria within 48 hours of admission 2 Patient's age >55 years pO2<60 mm Hg (8 kPa) Serum concentrations of albumin <32 g/l Glucose >10 mmol/l Lactate dehydrogenase >600 IU/l Aspartate aminotransferase >200 IU/l White blood cells>15´10 9 /l Calcium (corrected) <2.0 mmol/l l Urea >16 mmol/l Metabolic acidosis Rising aematocrit

Think of pancreatitis as a retroperitoneal burn, and you will understand the patient's high fluid requirements. Give 1 unit of colloid immediately, a further unit over 30 minutes, then crystalloid - 1 litre over 1 hour. After this, review the fluid balance in the light of pulse, blood pressure, and urine output (a urinary catheter with hourly measurement is essential). In patients with severe attacks or in patients in whom fluid balance is difficult to assess for other reasons, you should consider inserting a central line to monitor central venous pressure. Remember, however, that insertion of a central line is not without morbidity. These patients often require large amounts of intravenous fluid replacement, and renal failure will occur if this is not adequate.

Pancreatitis is very painful. Give adequate opiate analgesia to control the patient's pain and an antiemetic to stop him/her vomiting.

Insert a nasogastric tube if the patient is vomiting frequently.

Antibiotics probably reduce mortality. There is some evidence that imipenem is the most effective one, but antibiotics, and likewise H2 receptor antagonists, are controversial in acute pancreatitis, and you should find out what your consultant's preferences are.

The patient is at serious risk of developing respiratory failure, therefore give 100% oxygen. Measure blood gas concentrations regularly, especially if the patient's condition is deteriorating.

These patients are prone to specific metabolic abnormalities, which should be watched for. Acutely hypocalcaemia can result in tetany. Give 20 ml 10% calcium gluconate intravenously. Hyperglycaemia can also occur in the acute phase and will need to be controlled by giving insulin.

After the immediate management phase, when this patient is on the ward, do not be misled that just because they have not had an operation they are not in a serious condition. Acute pancreatitis kills young people, and you need to watch these patients carefully for complications such as respiratory and renal fail- ure, sepsis, and gastrointestinal haemorrhage.

 

Questions (1) How do you assess fluid replacement? (2) What are the "warning signs" for ruptured abdominal aortic aneurysm? Answers (1) Monitor pulse, blood pressure , urine output, skin perfusion, and CVP. Remember that the trend is more important than an individual reading. (2) Back pain, collapse , and pulsatile abdominal mass.