End of Posting Written Test
Lolz.. This morning short note test come out to be complication of operation.. Damn i don't like this kinda question. I hate short notes.. really.. But nway, i've made an article for us to look what we've answer and filling all the blanks that we have.. But hey, this is not an answer scheme or what so ever. It just for our understanding and merely a revision before we get ourself into a House Officer..
The role of the junior doctor postoperatively is to check that the patient has recovered from the anaesthetic, look at their observation charts and check their fluid balance. The operation note should have a section on specific postoperative management written by the surgeon, and is a guide that should be followed. For example, following a vascular graft operation — say, to the leg — you should always check the pulses, capillary refill and toe movement in the involved leg to ensure that the graft has not blocked off. A common question for exams concerns complications of surgery.
All operations carry a risk of complications. These can be divided into general and specific.
* General complications include those pertaining to the anaesthesia itself and those that can occur after any operation, such as a chest infection or DVT.
* Specific complications are those that occur because of the individual operation itself, such as cutting a nerve.
You can subdivide this classification by time, into complications that occur immediately, within the first 24 h; early, within the first week or so; late postoperative, occurring within the first month or so; and long term.
General immediate complications include those due to the anaesthetic, such as direct trauma to the mouth when intubating and reactions to the anaesthetic (inherited disorders or idiosyncratic reactions).
Other early complications including
* Chest infections
* Urinary retention or infections
* Deep vein thrombosis
* Bed sores.
Specific complications depend on the nature of the operation. In this category haemorrhage and wound infection are important.
This can be divided into primary, reactionary and secondary haemorrhage.
* Primary haemorrhage occurs during the operation, when a vessel is cut.
* Reactionary haemorrhage is when at the end of the operation the wound looks dry, but when the patient’s blood pressure and cardiac output rise to normal levels, bleeding begins, presumably from vessels that were not properly ligated during the operation.
* Secondary haemorrhage, occurring several days after the operation, is usually attributed to infection that erodes through a vessel.
These are most commonly caused by S. aureus (increasingly MRSA), although coliforms such as E. coli are also important. Wound infection is more likely if
• The operation is dirty (e.g. abdominal surgery)
• The duration of the operation is long (greater than 2 h)
• The patient is more susceptible (e.g. old age, immunosuppression, diabetes)
Minor wound infections, with a little redness and slight discharge, are relatively common and usually need just simple measures, such as regular wound dressing and perhaps antibiotics. More severe infections, common after abdominal operations, usually occur in the first week or so. The wound looks inflamed, and there may be cellulitis, discharge or localised abscess formation. The wound should be swabbed and maybe antibiotics started, but the only correct treatment for an abscess is drainage. This may mean simply removing a few of the surgical clips, and probing the wound, allowing the pus to discharge, or a further surgical procedure to open up the wound. The wound is then left to heal by secondary intention (i.e. to heal itself from within, with no further suturing).
This is an uncommon problem. It is usually due to an inadequate repair of the tissues (but infection, poor blood supply, malnutrition and steroids may all play a part in poor wound healing). Dehiscence usually occurs about a week after the operation. A warning sign is a serosanguinous discharge from the wound a few days before. The wound suddenly bursts open and in the case of a laparotomy the bowel protrudes outwards and is extremely alarming for the patient and the nursing staff. Sterile soaked swabs should be placed over the wound and the patient taken back to the theatre for repair.
An example of general and specific complications pertaining to a - gastrectomy is outlined below.
A small rise in temperature is common postoperatively. If the temperature spikes above 38'C or persists, then you should consider and look for the seven C's as potential causes. This is a common viva question.
1. Chest. Chest infection
2. Catheter. UTI
3. CVP line. Infected
4. Cannula. Superficial thrombophlebitis (solved by removing the cannula)
5. Cut. Wound infection
6. Collection. Subphrenic or pelvic abscess (may indicate a failure of anastomosis)
7. Calves. DVT (rumbling pyrexia in second postoperative week)
A chest infection is very common postoperatively, especially in patients who smoke or have pre-existing poor respiratory function. The mucus secretions are not cleared; these then clog up the smaller bronchi, which leads to collapse of the air spaces distal to the blockage (atelectasis). Inhaled organisms then infect the collapsed segments. In addition, thoracic and upper abdominal incisions cause pain and stop the patients from coughing up the secretions, and so they are much more likely to have basal atelectasis and develop chest infections. These patients should therefore be given adequate analgesia, have vigorous physiotherapy, and be encouraged
to cough up the phlegm (ideally whilst holding their wounds — applicable for chest and abdominal wounds).
A deep collection, such as a subphrenic or pelvic abscess, can occur after the patient has had generalised peritonitis. The patient usually presents with general malaise, nausea, pain (a subphrenic abscess may also cause pain felt in the shoulder tip), a swinging pyrexia and localised peritonitis.
A pelvic abscess often occurs 4–10 days postop., whereas a subphrenic abscess usually occurs a bit later, 7–21 days postop. Clinically, the patient appears to be recovering well, but then develops a fever and starts to feel unwell. The white cell count may be raised and a collection is identified on ultrasound or CT. Treatment is by drainage, either percutaneously under ultrasound or CT guidance, or by an open procedure. A drain is usually left in situ.
A small anastomotic leak usually causes a localised abscess which becomes sealed off by the omentum and the bowel. Clinically, the patient is slow to recover, but usually improves with intravenous antibiotics and fluids and delayed return to food. A larger anastomotic breakdown causes the patient to be very unwell, with anything from local peritonitis through to a rigid abdomen and septicaemia. The abscess needs to be drained, the peritoneal cavity washed out, and the two ends of the failed anastomosis can be brought out as temporary stomas.
A diagnosis of DVT and pulmonary embolus (PE) in the first instance is essentially a clinical one, as treatment is usually instituted before definitive diagnosis is made. A PE usually presents with pleuritic chest pain (stabbing and worse on inspiration). The textbooks tend to describe the findings you would see in a massive PE, although more commonly in the smaller PEs the findings are less impressive. Usually, the patient is tachycardic, maybe with a low-grade fever and maybe tachypnoeic, but not much else and they may even be asymptomatic. The ECG usually shows sinus tachycardia (the classic S1Q3T3, which most students know about, occurs when there is a large amount of right heart strain, in a large PE, and is rarely seen). The CXR is usually unhelpful but may show a small area of linear atelectasis.
Blood gas analysis is essential and you would expect to find a low PO2 (due to ventilation/perfusion mismatches) and a low PCO2 due to hyperventilation. Examination of the calves may or may not reveal evidence of a DVT. If a DVT or PE is suspected, a heparin infusion can be started before investigation but always check with a senior colleague before doing that, especially if the patient has had recent surgery.
To diagnose a DVT you can use duplex ultrasound (or a venogram). To diagnose a PE you can request a ventilation–perfusion scan, although the gold-standard is pulmonary angiography (note nowadays a spiral CT is used in some centres).
Other less common causes for a fever include infective diarrhoeas, drug reactions and blood transfusion reactions. If faced with a patient with a pyrexia you would obviously find out a little history and examine the patient properly. In a long case exam situation you could answer along the lines of, ‘I would listen to the chest, examine the abdomen, check the cannula sites, inspect the wound, etc. … My investigations would depend on my clinical findings but may involve sending a urine specimen, a full blood count and blood cultures, sending wound swabs or the tip of the central line for culture, etc.’
Collections within a wound (especially if they contain blood) are the perfect medium for colonisation of bacteria and hence infection.
A drain can be used to remove anticipated collections within a wound, but should never be used as a substitute for adequate haemostasis at the time of surgery.
Drains can be closed or open:
Closed drainage includes suction drainage (e.g. Redivac) where the collection is attracted into a container either by gravity or suction. This can then potentially reduce the risk of infection when used for large spaces or cavities, such as after a mastectomy or joint replacement. Drains are usually removed as soon as possible (usually 24–48 h) or as soon as the losses begin to tail off. Drains can also introduce infections and so they should not be left in for any longer than needed.
Open drainage (e.g. a piece of corrugated tubing with one end in the wound and the other in the dressing), allows small losses to escape from the wound. This is often employed in established abscesses after incision and drainage to allow any remaining collection a passage out of the wound. Some surgeons like to withdraw this type of drain in stages to allow the track to collapse behind it.
Other drains commonly asked about in exams include chest drains, T-tubes and percutaneous nephrostomies.
POSTOPERATIVE POOR URINE OUTPUT
This is a common exam question and can be classified as prerenal, renal or postrenal. The commonest causes of failure to pass urine postoperatively are postrenal.
Postrenal problems (commoner in males) include obstruction caused by a large prostate or a blocked catheter. Also, the patient may find initiation of micturition difficult for the following reasons:
1. Anticholinergic drugs or those with alpha adrenergic effects (e.g. the anaesthetic)
2. Pain (e.g. after a hernia repair)
3. Inhibition (e.g. because of strange surroundings or a nurse continually asking them if they have passed urine)
4. Opiates or epidural anaesthetics
Once the bladder reaches a certain volume of distension it fails to function properly and the patient goes into retention. Benign prostatic hypertrophy is an important predisposition and these patients are more likely to go into retention.
Prerenal causes are due to renal hypoperfusion because of either hypovolaemia or heart failure.
Renal causes — Acute renal failure is usually due to acute tubular necrosis.
How to handle?
Junior doctors are commonly called to see patients who have failed to pass urine postoperatively. Often this will be a patient you are covering but have not met before. It is, therefore, worth spending a little time getting a history and reading the patient’s notes. You should find out the type and date of operation and also search for clues pointing to whether the problem is prerenal or postrenal. Ask if there is any pain; an enlarged bladder causes suprapubic pain, although this is difficult to differentiate from pain in an abdominal wound (one exception is when there is an epidural in situ and there is no pain).
On examination you should look for signs of hypovolaemia (dry mucous membranes, decreased skin turgor, tachycardia, etc.), signs of heart failure (shortness of breath, tachycardia, raised CVP or JVP and bibasilar crepitations, peripheral oedema, etc.). A distended bladder palpable just above the pubis is dull to percussion and usually tender, making the patient want to pass urine, when compressed.
You can initially try conservative measures such as analgesia, privacy, sitting in a warm bath, etc., but if that fails then catheterisation is indicated. If you suspect that the cause is postrenal (i.e., distended bladder and discomfort), then the diagnosis is proven by catheterisation. A large residual volume of urine should drain (usually about 500 ml or more).
If the patient already has a catheter in situ, then the catheter should be flushed to ensure it is not blocked. If the urine coming out of the catheter is small amounts of concentrated dark urine, then the cause is likely to be prerenal anyway. You could dipstick the urine, testing for a high specific gravity (more than 1020) to prove this.
You should check the fluid balance charts (IO chart). Observe how much fluid has gone in before, during and since the operation and the measured urine output. Remember that a long laparotomy can lead to large losses of fluid by evaporation and this will not be measured on the charts. A urine output of less than about 30 ml/h is poor (oliguria). The patient should be catheterised anyway at this point to measure the hourly urine output.
U & Es should be sent; if there is a prerenal cause, the urea will be raised. If from your clinical examination and your assessment of the fluid balance charts you think the patient has a prerenal cause, then you should try a fluid challenge.
Fluid Challenge — 250–500 ml of normal saline given as a stat dose (unless you suspect blood loss as the cause, in which case the patient may be shocked and should be given colloids and blood). Then, observe the urine output over the next hour. If the urine output picks up, you have shown the patient to be in need of more fluid and the next bag should be speeded up.
If the patient has heart failure, the urine output will not pick up and the patient may become a little more breathless and the CVP might rise. If this occurs, a bolus dose of a loop diuretic, such as 40 mg of frusemide, will lead to a diuresis and a fall in the CVP. If the patient does not have a central line in at this point, you should ask a senior colleague for advice, as a central line is really necessary for knowing exactly what the state of vascular filling is and will help in the management.
Only after you have excluded a postrenal and a prerenal cause can you assume that there may be a renal problem and acute tubular necrosis has occurred. The creatinine will be raised and you should measure the urine and plasma osmolalities. The ratio of urine to plasma osmolality will be less than 1 (as opposed to prerenal oliguria, where the ratio will be more than 1). Advice from a renal physician should be sought early.
That's all folks.. Hope can help you a bit. I need a great night sleep tonight after tired using my brain for 12 hours straight. Good night.
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6/12/2009 04:49:00 PM | Author: fadzly