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Postoperative complications 35
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Table5.2 The Two- Level Wells score forestimating theclinical probability ofa pulmonary embolism
Clinical Feature Points
Clinical signs and symptoms of DVT (minimum of leg swelling and pain with palpation of the deep veins) 3
An alternative diagnosis is less likely than PE 3
Tachycardia >100 bpm 1.5
Immobilization for > 3days or surgery in the previous 4weeks 1.5
History of DVT or PE 1.5
Haemoptysis 1
Cancer, either undergoing treatment or treated in the last 6months, or palliated 1
Management
LMWH should be commenced immediately while diagnosis is confirmed.
DOACs are an alternative treatment option in
ambulatory patients.
Mechanical compression stockings – once antico-
• agulation has been started, patients should be encouraged to mobilize and to wear mechanical compression stockings, such as Thrombo­Embolus Deterrent (TED) stockings.
Pulmonary embolism
This occurs when a clot, usually originating in a femo­ral vein or a pelvic vein (and occasionally in a calf vein), detaches and travels to the heart to become lodged in the pulmonary arterial tree.
Clinical features
Pulmonary emboli classically occur around the 10th postoperative day but may occur sooner or later. The clinical features of PE may vary from dyspnoea, or mild pleuritic chest pain, to sudden death due to occlusion of the pulmonary artery trunk. Minor symptoms include pleuritic chest pain, dyspnoea and haemoptysis. Severe dyspnoea may occur with cyanosis and shock, and larger emboli may prompt acute right heart failure and death.
It is important to appreciate that pulmonary embolus may occur without any preceding warning signs of thrombosis in the leg. Indeed, once there are obvious clinical features of deep vein thrombosis, detachment of an organized and adherent clot from this limb is unlikely, especially if anticoagulant therapy has been commenced so that fresh clot formation is inhibited. The great majority of fatal pulmonary emboli are unheralded.
On examination, the patient has tachypnoea, often with a spike of fever. There is a tachycardia and a
raised jugular venous pressure (JVP) reflecting the pulmonary hypertension. A pleural rub may be audi­ble if the emboli are small and peripheral. Oxygen saturations on ambulation are frequently reduced.
Risk prediction ofa pulmonary embolus
Risk factors for PE, and their relative importance, are illustrated by the two- level PE Wells score in Table 5.2 and recommended by NICE. The Wells score also permits triage of patients:
Score 4: PE likely- investigate with CT pulmo-
nary angiography (CTPA)
Score <4: PE unlikely- initial investigation with
- dimer
Special investigations
Arterial blood gases may confirm hypoxaemia; hypocapnia (low CO ondary to tachypnoea.
Chest radiograph is often normal initially, but patchy shadowing of the affected segment may be present. It is more useful in identifying alternative causes such as pneumonia.
• - Dimer: A degradation product of fibrin present in the blood of patients with intravascular thrombi. A negative result effectively rules out thromboembo­lism in patients with a two-
CT pulmonary angiography (CTPA) is the defini- tive diagnostic test used when pulmonary emboli are suspected and is particularly useful when pul­monary disease is present.
5
Philip Steven Wells, contemporary, Haematologist and
Professor of Medicine, University of Ottawa, Ontario
) may also be present sec-
2
level PE Wells score <4.
5
illustrated
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Ventilation- perfusion (V/Q) scans can be considered where it is preferable to minimize the radiation dose exposure (such as pregnant patients).
Electrocardiogram (ECG) findings include rhythm
changes (e.g. atrial fibrillation, heart block) or fea­tures of right heart strain (ST segment depression in leads V1 to V3, III and aVF, with right axis devia­tion), as the heart pumps against the obstructed pulmonary arterial tree. The oft- mentioned ‘S1– Q3–T3’ pattern (S wave in lead I, with a Q wave and an inverted T wave in lead III) is seldom present.
Echocardiogram is most useful in patients with a
• confirmed massive PE to detect signs of right heart failure and pulmonary hypertension.
Treatment
1 Oxygen should be commenced if hypoxic. 2 LMWH at a therapeutic dose should be com-
menced immediately a PE is suspected pending the formal diagnosis.
3
DOAC therapy is commenced once a PE is con-
firmed, assuming it is safe to do so, and the likeli­hood of bleeding complications is minimal. It is continued for at least 3months.
Inferior vena cava (IVC) filters are designed to trap
4
fragmented thromboemboli from the deep leg veins en route to the pulmonary circulation (while pre­serving blood flow in the IVC). They are indicated in patients where anticoagulation is contraindicated or where emboli recur in spite of anticoagulation.
5
Thrombolysis may be indicated in the first 48
hours after PE if there is evidence of haemody­namic compromise. Thrombolysis can either be given into a peripheral vein (systemic thromboly­sis) or directly into the pulmonary arteries via a catheter (catheter- directed thrombolysis). Recent surgery (within 14days) is a contraindication to systemic thrombolysis due to risk of bleeding.
6 Surgical pulmonary embolectomy, with the patient
on cardiopulmonary bypass (Chapter13), is indi­cated in patients with massive pulmonary embo­lus who have a high risk of bleeding with thrombolysis and of dying without treatment.
Management ofthe unwell postoperative patient
Between 2% and 4% of postoperative patients will have a severe complication. The evaluation of a critically unwell patient is the same irrespective of the setting
and applies equally to a surgical patient. It is impor­tant to have a simple scheme to follow in each case. The ABCDE approach discussed next follows guid­ance from Resuscitation Council UK. It occurs in two phases, an initial rapid assessment followed by a more detailed assessment.
Initial assessment
The initial rapid assessment determines whether the patient looks unwell, whether they are able to communicate or whether they are unresponsive and require cardiopulmonary resuscitation. Surgical drains should be inspected for evidence of bleeding. Measurement of vital signs (pulse and blood pressure) and pulse oximetry are important, with ECG monitoring if available. Where possible venous access through a peripheral cannula should be obtained and can be combined with taking bloods.
ABCDE assessment
Following the initial assessment, a systematic ABCDE assessment takes place.
A: Airway
Airway obstruction: Is the airway clear, or does it require clearing/suctioning? The presence of stri­dor or wheeze imply partial airway obstruction. If wheeze is present, nebulized salbutamol may help.
Airway maintenance: Physical manoeuvres such as chin lift and jaw thrust lift the tongue from the oropharynx and allow airflow. A number of devices are available to maintain an airway:
nasopharyngeal airway;oropharyngeal airway (e.g. a Guedel airway);supraglottic airway device (e.g. an I- Gel),
which sits over the laryngeal inlet.
Endotracheal intubation: This may be required if an airway cannot otherwise be maintained. In extreme circumstances, a cricothyroid membrane puncture may be necessary, or a formal tracheos­tomy if circumstance and time permit.
Oxygen should be given at high concentration, aiming for an oxygen saturation of >94% (88%– 92% if at risk of hypercapnic respiratory failure, such as in some patients with chronic obstructive pulmonary disease [COPD]).
B: Breathing
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During the assessment of breathing, it is important to diagnose and treat conditions that are an immediate threat to life, such as a tension pneumothorax and massive haemothorax. In addition, non­ditions such as acute asthma and pulmonary oedema may need to be treated.
Signs of respiratory distress: the use of accessory
muscles of respiration, abdominal breathing and sweating.
Respiratory rate and depth: shallow and/or rapid
breaths (>25 bpm) are adverse signs.
Chest wall: Is the chest deformed? Is the trachea
deviated? Is there paradoxical movement or movement of only one hemithorax? Is surgical emphysema present suggesting pneumothorax?
Auscultation: may reveal features of pneumotho­rax or pneumonia.
Investigations include measurement of oxygen sat­urations and arterial blood gases help to establish the extent of respiratory compromise and the effects of treatment. A chest radiograph is important if chest pathology is suspected. If fluid overload is suspected, then diuretics or dialysis may be indicated, depend­ing on renal function.
surgical con-
C: Circulation
Shock is discussed in Chapter8. Hypovolaemia is the most likely cause of shock post operatively, but car­diac (e.g. myocardial infarction) and pulmonary (e.g. tension pneumothorax, PE) causes are also common. In assessing a surgical patient, the following should be considered:
Peripheral skin colour: Pallor, cyanosis and mot-
tling of hands or fingers suggest hypoperfusion.
Capillary refill time over 2 seconds suggests poor
perfusion but may also be present in the elderly or a cold environment.
Heart rate and pulse strength: Tachycardia and a
weak, thready pulse are common in shock.
Blood pressure. In young patients, the blood pres-
sure may be maintained in spite of significant fluid loss; the elderly tend not to be able to compensate for haemodynamic insults.
Auscultation of the heart may reveal a new mur-
mur or pericardial rub or heart sounds may be inaudible in cardiac tamponade.
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Urine output reflects end organ perfusion. Oliguria
(<30mL/h) suggests renal hypoperfusion.
The operative site and surgical drains, with par-
• ticular reference to features of peritonitis after abdominal surgery and blood in the drains. Note that significant intrabdominal or intrathoracic bleeding may occur with little or no blood appear­ing in the drains if the drains are blocked by clot.
An ECG and troponin levels should be checked to rule out an acute coronary syndrome. If bleeding is suspected, blood should be cross­assessment should be made as to whether an imme­diate return to theatre or urgent imaging is appropriate.
matched and an
D: Disability
Disability refers to the patient’s inability to follow commands, usually as a result of loss of conscious­ness. It may be a consequence of hypoxia or impaired perfusion of the brain, drugs (e.g. opiates, sedatives) or metabolic disorders (e.g. hypoglycaemia)
Assess the level of consciousness using the Glasgow
Coma Scale (Chapter17).
Check the capillary blood glucose level and treat
hypoglycaemia (glucose <4mmol/L) with a glu­cose infusion (50mL of 10% glucose, repeated as necessary).
Seizures require initial treatment with benzodiaz-
epines.
Exclude drug causes, including:
Opiates: small, pinpoint pupils, slow respira-
tion give naloxone (often requires repeated doses)
Benzodiazepine: give flumazenil
Exclude metabolic causes, such as hyponatraemia.
E: Exposure
Having gone through the aforementioned screening process, it is important that a full examination expos­ing the whole body is undertaken to ensure nothing has been missed.
At the end of the assessment, it should be clear what immediate investigations are required, their urgency, and where the patient is best nursed (ICU, high dependency unit or ward). Repeated observa­tion and reassessment are important adjuncts to achieving the correct diagnosis.
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Postoperative haemorrhage
Surgical bleeding may be divided into primary bleed­ing at the time of surgery; reactionary (or early) bleed­ing, which occurs within 24 hours of surgery; and secondary (or delayed) bleeding, which has a peak incidence between 7 and 10days. The consequences of bleeding may be hypovolaemia presenting with hypotension and tachycardia, or in closed spaces like the cranium, it may present with pressure effects (loss of consciousness).
or intraluminal bleeding which does not manifest immediately. This may occur in spite of the place­ment of drains. In this setting, the diagnosis is sug­gested by a patient becoming tachycardic and hypotensive, cold, sweaty and an appearance of pal­lor, all reflecting sympathetic nervous system stimu­lation shutting down the peripheral circulation. Chapter8 discusses hypovolemic shock. It should be remembered that the young tend to maintain their blood pressure by peripheral vasoconstriction in spite of significant haemorrhage, making the initial diagnosis difficult without a high index of suspicion.
Reactionary bleeding
Reactionary bleeding from the operative field may be a consequence of several things, such as:
a blood vessel that was in spasm, or minimally
bleeding intraoperatively but that opens up with restoration of normal blood pressure and patient warming;
• a vessel from which a ligature or laparoscopic clip has slipped;
unnoticed damage to an abdominal wall blood
vessel as a drain was placed while closing– com­monly the inferior epigastric artery in abdominal surgery, an intercostal artery in thoracic surgery;
a raw surgical bed following resection where hae-
• mostasis is difficult;
an underlying bleeding disorder, or anticoagula-
tion, or in patients taking aspirin or clopidogrel.
Secondary haemorrhage
Secondary haemorrhage is usually a consequence of infection in the operative field, possibly related to leakage of enteric contents or pancreatic juice. It is particularly common following resection of the head of pancreas when an enzyme leak may often present with catastrophic haemorrhage. It may also manifest with intraluminal bleeding from the site of an intesti­nal anastomosis, or haemorrhage from an infected vascular anastomosis.
Clinical features
Bleeding may be overt or concealed. Overt bleeding, where there is visible blood loss, is readily appreci­ated. In concealed bleeding there may be intracavity
Management
Initial management follows the ABCDE principles out­lined previously. Further management of postoperative bleeding depends on the manner of its presentation.
Reactionary haemorrhage often requires an
• immediate return to theatre, with little role for imaging.
Secondary haemorrhage may also require urgent
• re- exploration, but there is often a short period where investigations may take place. In some cases, radiological intervention, embolizing a bleeding vessel identified on a prior CT scan, may be the treatment of choice.
Postoperative fever
Postoperative fever may be defined as a temperature over 38 °C on two consecutive postoperative days or a single reading over 39 °C on any postoperative day. While it may be a manifestation of the inflammatory response to surgery, it may signify a serious postop­erative complication.
There are many possible causes of pyrexia, which can either be considered in terms of the timing post­operatively (Table 5.3) or by considering local and general causes both infectious and non- infectious:
Local causes
Infectious: wound infection, anastomotic leak
• Non- infectious: post- surgical inflammatory response
General causes
Infectious: aspiration, pneumonia, urinary tract
infection
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Table5.3 Causes ofpostoperative fever according topostoperative day
Phase Postoperative day Causes
Immediate 0–1 Blood transfusion reaction
Acute 0–3 Basal atelectasis
3–5 Pneumonia or aspiration
5–10 Surgical site infection
Early 10–28 Intra-
Delayed >28 Viral infections
Anaesthetic reaction (such as malignant hyperthermia) Bacteraemia from instrumentation of infected viscus Gas gangrene of dirty wound
Urinary tract infection
Deep venous thrombosis Surgical site infection Early anastomotic leak
Pneumonia or aspiration Line infection (e.g. central venous catheter) Pulmonary Embolus
abdominal collection
Partially treated deep space infection
• Non- infectious: blood transfusion reaction, anaesthetic reaction, drug reaction, DVT, PE, basal atelectasis and thyroid crisis
Patients who are immunosuppressed have a reduced inflammatory response and may lack fever and have minimal physical signs in spite of serious infection.
Assessment
A systemic approach is required in assessing the patient:
1
The ABCDE approach to evaluate severity
2 The operation notes should be reviewed, looking
in particular for any anastomoses or gastrointesti­nal (GI) tract sutures placed to repair bowel and any other operative concerns that may result in postoperative problems.
3
Examine systems, in turn, and in particular:
a Inspect the wound: superficial wound infection
or haematoma
b Inspect venous cannula sites: thrombophlebitis
is common when a cannula has remained in situ for a few days or when irritant infusions have passed through it
Examine the chest clinically, considering pul-
c
monary collapse, infection, infarction and sub­phrenic abscess
d
Examine the legs: deep vein thrombosis e Rectal examination: pelvic abscess f Urine culture: urinary infection g
Stool culture: for C. difficile toxin to exclude
enterocolitis
Consider the possibility of drug sensitivity
h
Following this, investigations should be initiated according to the most likely diagnosis or diagnoses. These may include:
Cultures of blood, lines, urine, sputum and stool
(where appropriate)
Chest radiograph
Duplex of the deep veins if DVT is suspected
Contrast- enhanced CT scan if intra- abdominal
cause is suspected
C TPA for suspected pulmonary embolus
In patients who are very unwell, it may be neces­sary to commence antibiotics before the initial assess­ment has been completed, in which case it is important to ensure that relevant cultures have been taken. The antibiotic most likely to treat the probable infective cause should be selected.
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Postoperative respiratory problems
Respiratory problems are common after surgery, being particularly common following open upper abdominal surgery. Causes can be divided into those presenting with shortness of breath and those where respiration is suppressed.
Aetiology
A useful classification of causes by system is:
1
Respiratory
a Atelectasis b Pneumonia, often secondary to aspiration c
Pneumothorax, e.g. from central line placement
d Exacerbation of underlying COPD or asthma
2 Cardiovascular
a Left ventricular failure due to fluid overload b
Myocardial infarction
c PE
3 General
a Metabolic acidosis, with compensatory hyper-
ventilation giving the impression of breathlessness
b
Anaemia
4 Suppressed respiration
a Neuromuscular blockade, due to incomplete
anaesthetic reversal postoperatively
b
Opiates causing respiratory depression, espe-
cially in the presence of renal failure
Sleep apnoea
c
ABCDE assessment and management should be undertaken. Oxygen should be administered, and the underlying cause investigated, which usually requires arterial blood gases, chest radiograph and 12-
lead ECG.
Pulmonary collapse andinfection
Some degree of pulmonary collapse, also called atelec­tasis, occurs after almost every abdominal or transtho­racic procedure within the first 48 hours of surgery. Mucus is retained in the bronchial tree, blocking the smaller bronchi; the alveolar air is then absorbed, with collapse of the supplied lung segments (usually the basal lobes). The collapsed segment or entire lung con­tinues to be perfused and acts as a shunt, which reduces oxygenation. The lung segment may become secondarily infected by inhaled or aspirated organ­isms, and, rarely, abscess formation may occur.
Aetiology
Preoperative factors
• chronic obstructive airway disease;
smoking;
• asthma (which increases the amount of bronchial secretion);
chest wall disease, such as ankylosing spondylitis,
• which restricts ventilation and makes coughing difficult;
poor mobility;
• obesity.
Operative factors
• anaesthetic drugs, such as atropine, which increases the viscosity of secretions;
surgery in the upper abdomen or thorax;
• long operative time;
• excessive fluid replacement (goal- directed replacement – the gold standard using cardiac output monitoring).
Opiates, renal failure, andrespiratory depression
Opiates are partially eliminated through the kidneys, therefore clearance is impaired by renal failure. Naloxone will reverse the effects of the opiates but may require repeated doses because the half- life of naloxone (60–90 minutes) is much shorter than that of most opiates. An infusion of naloxone is usually required in patients with renal failure if a delayed res­piratory arrest is to be avoided.
Postoperative factors
• insufficient analgesia to permit full inspiration opening all alveoli and expectoration;
• abdominal distension causing diaphragmatic splinting.
Clinical features
The patient is dyspnoeic with a rapid pulse and elevated temperature. There may be cyanosis. The
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patient attempts to cough, but this is painful and, unless encouraged, may fail to expectorate. The spu­tum is at first frothy and clear but may become puru­lent later, diagnostic of secondary infection. The chest movements are diminished, particularly on the affected side; there may be basal dullness with reduced air entry and coarse crackles.
The haemoglobin oxygen saturation on pulse oxime­try may fall, and chest radiograph may reveal an opacity of the involved segment(s) (usually basal or midzone), together with mediastinal shift to the affected side if a significant portion of one lung is affected.
Treatment
Preoperatively
Breathing exercises are given, and smoking is dis­couraged. Any prior chest infection is treated, and surgery delayed, if possible, until the chest is optimized.
Operatively
The surgical approach associated with the least res­piratory compromise should be considered where appropriate; laparoscopic surgery is preferable to open surgery. Epidural or spinal anaesthesia is used where possible and continued postoperatively. Intercostal nerve blocks may be used for thoracic or upper abdominal surgery and continued postopera­tively. Transversus abdominus plane (TAP) anaes­thetic blocks or catheters may be placed alongside abdominal wounds to minimize immediate postop­erative pain.
Postoperatively
The patient is encouraged to take deep breaths and cough while supporting any abdominal wound with their hands. Chest physiotherapy, saline/salbutamol nebulizers and incentive spirometry are initiated. Incentive spirometry encourages patients to take slow, deep breaths and uses devices that provide vis­ual cues to the patients to confirm that the desired flow or volume has been achieved.
In the event of development of shortness of breath or low oxygen saturations, a full ABCDE assessment should take place to resuscitate the patient and con­firm the diagnosis of chest infection with chest radio­graph. Sputum cultures are sent, and antibiotic treatment begun.
It is important to recognize adverse clinical features that suggest that increased levels of respiratory support may be required, ranging from increased inspired oxy­gen to non­airways pressure [CPAP]) to intubation and ventilation on an intensive care unit. Recognizing these can allow pre­scores have developed to aid nurses and doctors in rec­ognizing such patients, such as the National Early Warning Score (NEWS) 2 used in the UK. Features sug­gesting respiratory support may be required include:
use of accessory muscles, intercostal recession;
respiratory rate >25 bpm, which may be followed
respiratory rate <8 bpm;
decreasing vital capacity (shallow breathing);
• tachycardia and sweating (reflecting sympathetic
agitation and restlessness;
sitting up, unwilling to lie flat;
• hypoxaemia, with pO
HbO
• hypercapnia;
• impaired level of consciousness.
invasive ventilation (e.g. continuous positive
emptive treatment. A number of early warning
by exhaustion and respiratory failure;
activity);
< 11kPa when the FiO2 is
40%, or <8kPa on air;
saturations ≤90%;
2
2
Postoperative ileus
This is discussed in Chapter30.
Abdominal wound dehiscence
Wound dehiscence is an uncommon complication of surgery, being more common after emergency than elective surgery. It may be divided into superficial and full-
thickness dehiscence:
Superficial dehiscence is a failure of the skin clo-
sure such that subcutaneous tissue and even rec­tus sheath become exposed.
Full- thickness dehiscence occurs when all layers of
the wound fail such that some of the abdominal contents (usually small bowel) prolapse out. This is often termed a ‘burst abdomen’, a term that reflects the shock of patient and staff alike when they encounter bowel in the bed.
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Risk factors
Predisposing factors can be divided into preoperative, operative and postoperative as follows:
Preoperative
Malnutrition (common with some cancers and emer­gency conditions), diabetes, COPD, obesity, smoking, liver and renal failure, steroids and mTOR inhibitors (everolimus and sirolimus). Previous radiotherapy may compromise the vascularity of a wound, render­ing it more prone to break down.
Operative
Emergency surgery, intra- abdominal sepsis, long operations (increased incidence of wound infection), early reoperations where the fascia becomes friable, poor suture choice (insufficient strength or rapidly absorbed) and poor operative technique. Midline incisions are more likely to dehiscence than parame­dian or grid iron appendix incisions.
One recommended technique for abdominal clo­sure uses a continuous suture that is four times the length of the wound, with individual ‘bites’ placed 1 cm apart (Jenkins’ rule proposed even smaller bites of 5 mm. The key is to place the suture into healthy fascia without tension either laterally or longitudinally to avoid a ‘cheese wire’ effect cutting through the fascia.
6
). Some researchers have
Postoperative
Excessive coughing (such as with COPD or chest infec­tion), abdominal distension due to prolonged ileus or obstruction, wound infection, wound haematoma and delayed introduction of nutrition. Prolonged periods in intensive care have also been cited as a cause.
nal cavity after operation and which seeps through the wound breakdown.
The wound may open slightly, at which point loose suture material and the smooth pink surface of small bowel may be seen in its depths, or a more extensive dehiscence may occur, especially after coughing or straining, with intestine and omentum prolapsing through.
Management
Depends on the clinical presentation. In both types of dehiscence, wound swabs are taken to determine the nature of any infecting organism.
Superficial dehiscence should be explored to con-
firm the integrity of the deep fascia and then man­aged expectantly with wound dressings or negative pressure dressings.
Full- thickness dehiscence is a shocking and psy-
chologically disturbing occurrence for the patient who will need strong reassurance. The bowel is covered with a sterile dressing soaked in saline, and the patient returned to theatre. The abdomen is explored, and wound edges debrided. If there is no distension, the wound is closed primarily once again. In the presence of distension such that the wound edges will not oppose, the abdomen may be left open as a laparostomy or a vacuum­wound closure device with mesh- mediated fascial traction may be considered. This technique involves suturing a polypropylene mesh across the wound to bridge the gap in the fascial closure. The mesh is gradually tightened over several days under general anaesthetic to draw the muscles together and aid delayed closure.
Following closure of superficial or full­dehiscence, there is a high incidence of subsequent incisional hernia.
assisted
thickness
Clinical features
Signs usually develop approximately 10 days after surgery. Overt wound infection may precede dehis­cence, but often, there is a small defect in the skin where pink fluid discharges. This represents the blood- stained serous effusion, which is always pre­sent during the first week or two within the abdomi-
6
Terence PN Jenkins, Surgeon, St Luke’s Hospital and Royal
Surrey County Hospital, Guildford.
Anastomotic leak
An anastomosis is a join between two luminal struc­tures, such as bowel, bile duct, pancreatic duct, ureter or blood vessel. It may be hand sewn or stapled, the latter being most common in bowel anastomoses. An anastomotic leak results in luminal contents passing through the suture or staple line into the extra- luminal space.
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Risk factors
There are several factors that increase the risk of an anastomotic leak. A classification for an anastomotic leak following a bowel anastomosis is given below, although many of the factors apply to anastomoses of other luminal structures:
Preoperative: Medication (such as corticoster-
oids), smoking, diabetes, obesity, malnutrition, intra-
abdominal sepsis, liver disease and cirrho­sis, neoadjuvant chemotherapy or radiotherapy for cancer
Operative: emergency surgery, long intra- operative
• time, peritoneal contamination (pus or faeces), site of anastomosis (e.g. in the rectum, oesophagus or pancreas), poor blood supply to the cut ends of bowel, and distal obstruction. Operative technique is important, to avoid poor blood supply, tension across the anastomosis, malignancy at the anasto­mosis (i.e. inadequate resection) and incorrect ori­entation (e.g. a twist of the bowel)
Postoperative: hypotension, inotropic support (vasoconstriction reducing blood supply to the anastomosis) and respiratory failure
Clinical features
Anastomotic leaks are important to recognize early. The consequences of a leak depend on the luminal contents. In the case of a vascular anastomosis, it is associated with haemorrhage, which is usually brisk with arterial anastomoses. Bile and urine cause a ster­ile chemical peritonitis. In contrast, a pancreatic duct leak causes release of digestive enzymes, which may result in necrosis of neighbouring tissues, causing bowel perforation or haemorrhage. A leak from a bowel anastomosis causes peritoneal soiling and sep­sis. The remainder of this section considers bowel anastomotic leaks, but similar principles apply to other anastomoses.
Early diagnosis and treatment are important. Delay leads to prolonged contamination of the abdomen or chest by the luminal contents, leading to the develop-
organ
failure and death.
Leaks from a bowel anastomosis classically present with abdominal pain combined with high fever, a leu­cocytosis and raised CRP. It can present without local­izing abdominal signs, or with cardiovascular instability, atrial fibrillation or even myocardial infarction. For this
reason, it should be considered whenever a patient’s recovery is not progressing as normal. On examination, patients may be pyrexial and tachycardic and may have signs of peritonism. There may be faeculant material in the wound or drains.
Early postoperatively, a leak will drain freely into the peritoneal cavity. Later, by day 10, the anastomo­sis tends to be walled off by inflammatory tissue and surrounding bowel and omentum so the leak may be ‘contained’.
Special investigations
CT scan will demonstrate free gas and fluid in the
peritoneal cavity. Oral contrast such as gastro­grafin will be seen to leak outside of the bowel lumen.
Endoscopy, usually under anaesthetic, to directly
inspect an oesophago- gastric or rectal anastomo­sis will reveal a defect.
Management
The definitive management varies depending on the site of the leak, its extent, the amount of contamina­tion and the physiological status of the patient. It also depends on whether the anastomosis was in a de­functioned segment of bowel, that is, one for which a proximal stoma was fashioned to divert the faecal stream to permit healing.
Contained leaks
Contained leaks are generally managed by drainage. This usually involves a radiologically placed drain into the infected cavity. It is particularly effective where the faecal stream has been diverted by a proxi­mal stoma during the initial surgery. An alternative for oesophago- gastric and low rectal anastomotic leaks is to pass an endoluminal vacuum therapy device such as the Endo­lumen into the cavity. This is a sponge through which negative pressure is applied, which prompts granula­tion tissue and healing. The sponge needs changing every 2 to 3days, usually under general anaesthetic.
SPONGE® via the bowel
Uncontained (‘free’) leaks
Surgery is required for an uncontained leak, to wash out the infected material. This may be performed lap­aroscopically if the original surgery was minimally
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invasive but is more commonly performed via an open laparotomy approach. The anastomosis usually requires resection with formation of a proximal end stoma. Repair of an anastomosis is seldom successful because of local sepsis, poor vascularity and subopti­mal condition of the patient.
Whether a contained or uncontained leak, optimiz­ing the patient’s nutrition is important and parenteral nutrition is usually required.
Postoperative fistula
A fistula is as an abnormal connection between two epithelial surfaces; an enterocutaneous fistula is a communication between the bowel and the skin. Most enterocutaneous fistulae are a consequence of anastomotic leaks or inadvertent injury to the bowel during surgery or following trauma. Spontaneous enterocutaneous fistulae may occur from Crohn’s dis­ease, malignancy, diverticulitis or radiotherapy.
Similar factors are responsible for postoperative fistulas and anastomotic leaks. An alternative classifi­cation is to consider them in terms of general factors and local factors.
General factors include uraemia, anaemia, jaun­dice, protein deficiency or cachexia from malignant disease.
Local factors include factors affecting anastomotic healing (e.g. blood supply and tension), local sepsis before or during surgery, a distal obstruction or the presence of local malignancy or chronic inflamma­tion such as Crohn’s disease.
Clinical features
Diagnosis of a fistula is usually obvious, with bowel contents or bile leaking from the wound or drain site, usually between 10 and 14days post- surgery. If the diagnosis is in doubt, the fluid can be tested for biliru­bin to diagnose a biliary leak and creatinine for a uri­nary tract leak, while the fluid from a pancreatic or small bowel leak is rich in amylase. Water- soluble con­trast or methylene blue can be given by mouth and the fistula imaged or observed for the presence of dye.
The patient is typically pyrexial with localized abdominal pain. The enzyme- rich fluid of the upper alimentary tract and of a pancreatic fistula produces rapid excoriation of the surrounding skin. This is less marked in a faecal fistula, as the contents of the colon are relatively poor in proteolytic enzymes.
Classication
Fistulas are usually classified by the volume of output and the area of the GI tract involved in the fistula.
Output: High output (>500 mL over 24 hours),
moderate output (between 200 and 500mL over 24 hours) and low output (<200mL over 24 hours).
Site of origin of fistula: oesophageal, gastroduode-
• nal, small bowel, large bowel. A fistula occurring from bowel exposed in an open wound is termed an enteroatmospheric fistula.
Treatment
The management has four aims, which can be consid­ered to form the acronym SNAP:
1
Skin and Sepsis control
a Local control to protect the skin around the fis-
tula: The edges of the wound are covered by Stomahesive® (which adheres even to moist surfaces) or aluminium paste or silicone bar­rier cream. It may be possible to collect the effluent by means of a stoma appliance and thus reduce skin soiling. If the mouth of the fistula is large, continuous suction may be necessary.
Antibiotics and radiological drainage of puru-
b
lent collections: Repeated drainage may be necessary.
2
Nutritional support: In a high alimentary fistula,
gastric and pancreatic secretions, which are stim­ulated when feeding enterally, are lost through the fistula. Instead, the patient is kept ‘nil by mouth’ and parenteral nutrition commenced (Chapter3). A low fistula, occurring in the distal alimentary tract, may be managed with an elemental diet given by mouth. This is rapidly absorbed in the upper intestine and is thus not lost through the fis­tula. Regular monitoring of nutritional state is important.
3 Anatomical delineation of the fistula: A CT scan
with water- soluble contrast either by mouth or via the fistula tract will identify the site of leakage, assess the likelihood of spontaneous closure and facilitate planning of any future intervention.
4 Procedure for definitive control: Whether closure of
the fistula tract is required depends on the likelihood of spontaneous closure. Good nutritional support, eradication of sepsis, no distal obstruction, low fis­tula output and small bowel fistulas are associated
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