Core Topics in General & Emergency Surgery: Companion to Specialist Surgical Practice (85 page)

The management of abdominal sepsis in the emergency surgical admission is that of the underlying disease, as covered elsewhere in this book. The aim is to deal not only with the sepsis, but also to deal definitively with the underlying disease process or cause. In all patients, pus must be drained and dead tissue removed with specimens submitted for urgent microbiology. While localised collections can be drained percutaneously, generalised peritonitis remains an indication for laparotomy. Exceptions to this rule include primary spontaneous bacterial peritonitis and acute pancreatitis. There is an increasing use of laparoscopy in the management of specific surgical conditions causing abdominal sepsis (discussed further in
Chapters 6
,
Chapters 8
,
9
,
10
). However, it must be remembered that a laparoscopic approach may not allow sufficient access to adequately debride and drain the septic focus, and that the physiological sequelae of a pneumoperitoneum may be poorly tolerated in those with septic shock.

Whether treatment is radiological or surgical, adequate preparation is essential (see also
Chapter 16
). Coagulopathy must be excluded or corrected beforehand and blood for transfusion should be available. Although drainage may be an essential prerequisite to resolution of sepsis, it is not infrequent for bacteraemia, as a consequence of the intervention, to cause a temporary deterioration in the patient's condition. Indeed, a bacteraemia may represent the ‘second hit’ that precipitates MODS. Such circumstances should be anticipated and an appropriate level of post-procedure care arranged beforehand.

With more complex cases and with older and sicker patients, treatment may need to be tempered in order to be survivable. However, there is a balance to be struck as inadequate treatment will condemn the patient to recurrent sepsis and likely death. The opinion of senior colleagues and specialist centres can be invaluable.

Image-guided percutanous drainage of both spontaneous and postoperative intra-abdominal collections has reported success rates of 70–90%.
^25
,
26
The importance of adequate systemic support for the patient having imaging or image-guided intervention should nowadays be self-evident. Surgeons have a role to play in this, which may involve the assistance of anaesthetists. Percutaneous procedures may be less invasive than open surgery but will only be effective if good drainage is achieved. Many percutaneous drains are narrow and inadequate when infected fluid is viscous or contains necrotic tissue. Larger or multiple drains may be more effective and daily flushing can help. When radiological drains are placed for abdominal sepsis, the responsibility lies with the surgical team to ensure that the patient's condition improves as expected. Failure to respond to radiological intervention is another indication for laparotomy.

When open surgery is performed for sepsis, the procedure will vary according to the underlying pathology. Nonetheless, general principles apply in that the most straightforward adequate procedure is often preferable to a complex and time-consuming operation. The aim is to improve the patient's condition sufficiently without risking further complication. There is a current trend towards primary bowel resection and anastomosis in the acute setting, but this should be avoided in unstable patients, the presence of significant comorbidity, or heavy contamination. Generous saline lavage is recommended on completion of the procedure but there is nothing to be gained either by removing fibrinous debris piecemeal or by postoperative lavage.
¹⁹
Delayed skin wound closure may be preferable to primary suture, or wounds may be left to close by secondary intention if sepsis is substantial.

Obtaining informed consent for treatment will involve both patient and relatives. The potential severity of the situation should not be underestimated and the possibility of death, stoma creation, the need for intensive care treatment and further surgery will usually need to be discussed explicitly. The average mortality for an emergency laparotomy is around 15%, and increases with age and physiological disturbance.
¹⁴
Complementing clinical assessment with an objective determinant of risk from a scoring system (such as P-Possum) is valuable to help focus efforts.
^14
,
27
See also
Chapter 15
.

Often the early phase of postoperative care will be delivered on the surgical high-dependency unit (HDU) or ICU. Although we, as surgeons, may sometimes feel uncomfortable on ICU, there is a range of skills that we are usually best placed to deliver, and close cooperation between surgeon and intensivist is essential (
Box 18.6
).

Not infrequently, the surgeon is also involved with the assessment and management of patients already on the ICU who develop recurrent abdominal sepsis. The outcome of patients with abdominal sepsis who require ICU treatment depends on age, comorbidities, source of sepsis and organ dysfunction. Control of the source of sepsis is essential for survival among patients with MOF. When sepsis is eradicated successfully from these patients by surgery over 60% survive, whereas survival is close to zero if significant abdominal sepsis continues.
²⁸

The principal causes of recurrent abdominal sepsis in the ICU are shown in
Box 18.7
. The reader is referred to
Chapters 6
,
Chapters 8
,
9
and
10
for the management of each organ-specific condition. Leaking anastomosis remains the commonest single cause and should be actively suspected in all ‘at-risk patients’ who are critically ill or deteriorating. Enterotomy during difficult surgery is not uncommon, occurring in up to 20% of patients,
²⁹
and these can also leak in the postoperative period. Gastrostomy or other tubes inserted into the gut occasionally leak as well and this is more likely when tissue healing is poor.

Postoperative small-bowel ileus usually resolves within days, regardless of the extent of bowel handling.
³⁰
Drugs, especially opiates, or electrolyte abnormalities (hypokalaemia, uraemia) may delay resolution, but failure to progress may also indicate ongoing retroperitoneal or abdominal pathology. Ileus may be difficult to distinguish from adhesive obstruction, and contrast studies may clarify the situation (see also
Chapter 5
). Adhesive obstruction frequently resolves but refractory cases occasionally require laparotomy. However, in a hostile abdomen, such as found in abdominal sepsis, considerable caution should be exercised in subjecting the patient to further surgery.
³¹
Whereas a 5- to 7-day period of non-operative treatment might be acceptable in the presence of straightforward adhesion obstruction (and on occasions perhaps even longer if nutrition is supported), one should be prepared to wait for considerably longer when faced with a hostile abdomen, provided specific indications for surgery are not present. These indications include a known point of unrelieved complete obstruction or where there is a known septic focus.

Re-operating in abdominal sepsis is always difficult: the timing of the most recent operation will influence the degree of difficulty and hence the risk of future complications. Beyond 72 hours adhesions will make surgery increasingly difficult and the risk of bowel damage increases: often the adhesions are stronger than the bowel. Entry to the abdomen can be difficult and an extension of the previous midline incision may help. Adhesions are generally most dense around any site of inflammation, as well as a recent incision. Here, having a preoperative CT scan comes into its own, guiding the surgeon as to the relative necessity to dissect in any difficult area. While a full laparotomy is ideal, prolonged dissection of adhesions in an area not thought from CT to contain inflammation or a collection may not be merited.

The surgeon must deal with the sepsis as thoroughly as possible but also simply and quickly. Prolonged and complex procedures will likely lead to a systemic deterioration in the patient and the prospect of bowel anastomoses healing under these adverse circumstances is not as high as one would like. The ability of the patient to withstand further surgery for further complications is very much lower next time around,
²⁸
and the surgeon should see the present operation as the best opportunity for salvaging the patient. Intestinal reconstruction can be attempted when the patient is well and recovered, some months later.

Hence, in general terms the simplest and safest procedure will be best. This holds true especially in the patient who already has incipient or established organ failure: drain sepsis, debride any necrotic tissue and exteriorise any leaking bowel or anastomoses as stomas. Most controversy relates to the management of enteric and colorectal anastomotic leaks. While in a well patient, with a small leak and minimal contamination, preservation of a repaired anastomosis with proximal defunctioning and local drainage may be appropriate, it is all too often foolhardy in the critically ill. Preserving the anastomosis might work but there is a significant risk of further peritonitis and likely death as further acute surgery will seldom be successful. A first salvage operation in an ICU patient will successfully eradicate sepsis over 40% of the time but a second operation carries a success rate of only 25% and a third operation only 7%.
²⁸
This is reflected in the rate of survival.

In difficult cases, the surgeon must be ready to employ alternative strategies, although it remains essential to drain significant collections of pus or enteric content and to debride any necrotic tissue. In the multiply operated septic abdomen, it may not be possible to take down and exteriorise the prime source of sepsis because of dense adhesions or the anatomical location (oesophagus, duodenum). For inaccessible pelvic sepsis arising from distal small bowel or colon, it may be possible to identify and exteriorise a proximal loop of jejunum without entering and damaging the matted pelvic loops other than to achieve necessary drainage. This will usually relieve the sepsis but at the price of a high-output stoma and prolonged intravenous feeding. For oesophagogastric or duodenal sepsis, all that may be possible is to drain collections and leave large tube or sump drains beside the leaking anastomosis or other septic focus. Placing a second tube in the hole to create a controlled fistula is also of merit. Proximal intestinal contents or secretions can sometimes be diverted away by tube gastrostomy or other techniques, although each has its complications. A further option in difficult situations or resistant cases is to gain entry to locules of pus or enteric content, then to leave the abdomen open as a laparostomy (
Fig. 18.2
). Further pus or enteric content will usually find its way to the surface, assisted by subsequent manual lavage on the ICU or in theatre as necessary.

In addition to their role in draining proximal gut secretions, gastrostomy and enterostomy tubes can be usefully placed to facilitate future, and often prolonged, enteral feeding. The same tube can serve both roles: drainage initially, then feeding as intestinal function returns, provided there is no persisting distal bowel leak. These laparotomies are often oozy and contaminated, and many surgeons would leave large drains (24Ch tube or sump) in the subphrenic spaces and pelvis at the end of the procedure. This is particularly so for certain deep cavities (e.g. psoas abscess) or when further leakage is likely or inevitable. Large Foley catheters can be used to intubate inaccessible bowel to create a controlled fistula (typically the duodenum) and it is often advisable to place an additional large drain just outside the bowel. There is a particular role for local lavage in pancreatic necrosis (see
Chapter 8
) but, otherwise, continuing lavage down abdominal drains in the postoperative period is of no proven benefit.

Outcome from surgery for abdominal sepsis in the ICU patient depends on many factors. Age and eradication of sepsis have been discussed but numbers of failed organs, comorbid conditions and the underlying surgical disease are also important. Overall, 30–40% will survive,
²⁸
but a further factor that is associated with survival is the early response to the first operation in the ICU. If the patient has improved clinically within 48 hours then survival is much better (80%) than if the patient does not improve in this time frame (10%). Given the cost of intensive care, attempts have been made using a variety of scoring systems to define numerically those patients with negligible chance of survival (see
Chapter 15
). However, due to the heterogeneity of the patient group and the nature of scoring systems in general, it is not possible to use them for decision-making in individual patients. Clinical judgment is most important and the scoring systems remain primarily tools for audit and research.