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Post-operative septicemia

Shobhana Mohandas:  TOGS, Vol 1 No1 March 2005.

 

 

Post-operative septicemia

 Surgical complications are rare in the gynaecologic patient and with modern technology, it is rare to see  post-operative patients go into septic shock.  However, once in a while, a seemingly innoccuous caesarian section or hysterectomy can sometimes end in septic shock, which quite often takes the patient’s life.  This may happen in spite of all precautions that the doctor apparently takes to avoid catastrophes. Is it true that we can prevent all septic shocks? Does patient factor have anything to do with it?  Probably, if the patient is in the pink of health, small lapses will be covered by the body’s defence mechanisms.  But, in the slightly compromised patient, giving optimum conditions at time of surgery and in the post-operative period can probably minimise the rate of sepsis. Some of the views given below are personal views gained after both good and bad experiences and some of the views are backed by literature. 

Preventive strategies:

Hospital administration: Sterilisation of instruments should be given top priority in all hospitals.  Autoclaved instruments should be packed in adequate quantities in the operation theatre.  In case of emergencies, under no circumstance, should  hurriedly boiled instruments be used.  Chemical indicators are available to check if the instruments are really sterile or not.  These are small strips which change colour if the instruments are adequately sterilised.  In case of inadequacies, these strips will not attain the desired colour.  Using these strips may appear costly when things are going smooth. But prevention is better than cure and it is better to invest in scientific methods of checking sterilisation rather than regret over septic shocks. 

The staff handling instruments in the theatre should be either fully qualified as in major hospitals, or adequately trained in smaller hospitals. For this the doctor in charge of the hospital will probably have to learn the nuances of sterilisation herself/himself to accommodate for frequent change of staff.

Post-operative care is very important not only in the immediate post-operative period, but also in the next few days.  Early discharges being the norm of the day,  care of the patient may take a back seat on the 2nd or 3rd day, as many patients, specially following endoscopy will get discharged by then.  The basic rule of thumb should be that any patient who is not getting better and better as the hours and days go by needs close surveillance.  A patient who says, my pain/distension, nausea etc is worse today compared to yesterday needs constant surveillance.  It is here that the role of nursing assumes importance. 

A rising pulse may be an important sign of serious infection in the body.  In the absence of a falling Blood pressure, it may be mistakenly construed to be a sign of anxiety. When a rising pulse along with breathlessness or signs of peritonitis, is present, the clinician should be on high alert.  The monitoring of pulse, blood pressure and respiration,  should be delegated to the senior staff.  The senior staff will more often than not ask the student nurse to record the pulse and temperature.  But it would be prudent for the doctor to supervise the vital parametres by oneself in special cases at least, so that the staff will be more diligent in monitoring the patient .  One may  encounter situations where over the phone a casual inquiry about the pulse invariably is given  the answer, 80 to 90 per minute. If the doctor goes personally to monitor the pulse it may be 120 per minute, which will hurriedly be attributed to patient anxiety.  Surprise checks of vital parametres by treating physicians will go a long way in optimising the monitoring of vital parametres. 

Surgical risks:

Just as sterilising the instruments is important, so also proper antiseptic precautions while performing surgery is  important.  The breach in adhering to principles of antisepsis are most likely to occur in difficult cases on difficult days and invariably these are the cases which are prone to infections.  Invariable pricks in the gloves, will decrease as the years go by in a surgeon’s life, but it is always better to clean the hands with alcohol before surgery, be it the cheap methylated spirit or the costlier company made solutions. In case of inadvertent pricks or unsterile touches, strictness in changing gloves will take away only 2 minutes from the operating time, but the habit once learned, will help on a difficult day, sometime,some day....

 

Factors that can reduce infection rate:

1.Time: Decreasing the time of surgery can reduce the rate of complications.  Surgery prolonged for more than 3hours  may also be associated with increased risk of pulmonary infections and this risk cannot   be reduced with the use of  pre-operative antibiotics1. Having a well planned theatre can reduce operating time to a great extent. Additional instruments should be readily available so that precious time is not lost searching for it.  The surgeon should preferably be washed up in the theatre by the time the anaesthetist gives anaesthesia. 

2.Antibiotics:

In a study on patients undergoing elective colorectal surgery, Jimenez et al have summarized that bowel preparation is not the key factor that prevents infection in patients undergoing colorectal surgery2.  They find that intravenous administration of a long acting injectable antibiotic with adequate coverage for aerobic and anaerobic bacteria with adequate serum levels at the time of incision was very effective in reducing infection rate.  Frequently-used antibiotics such as cefuroxime with metronidazole and gentamicin with metronidazole may be adequate.

The conclusions drawn in this study could probably be extrapolated to gynecological patients undergoing bowel surgery, either electively or because the bowel was inadvertently injured during surgery. 

3.Blood transfusion:

Intra and Post-operative blood transfusion was assossiated with increased infection rate.  Allogenic leukocytes in the transfused blood is hypothesized to cause immunosuppression and consequent impaired immunity.  Leucocyte depleted blood was found to have the same rate of infection as untransfused patients, supporting the above hypothesis.  

4. Intraoperative hypothermia appeared to o triple the rate of postoperative infectious complications. Maintaining the temperature of the patient at 36.5degree Celsius during surgery could reduce infection rate. 

5.Increased oxygen tension by way of administering 80%oxygen in the first two post-operative days increased the ability for oxidative killing at the surgical site, along with increased neutrophil activity leading to improved tissue healing according to a study by Greif et al2. This may mean that oxygen administration for longer periods will benefit the patient who has undergone prolonged handling of the bowel/extensive adhesiolysis.

Post-operative period: Peritonitis and pulmonary infection are common modes of infection which in compromised patients lead to the toxic shock state.

Classic signs of peritonitis: The classic signs and symptoms of peritonitis include pain, distention, fever and leukocytosis.  The vital signs and input and output must be carefully monitored.  If the situation does not improve withn 12- 24 hours, or worsens, immediate exploration is indicated3.  Mild hypotension, tachycardia, fluid retention and change in mental status are signs of sepsis.

Antibiotic management of patients with peritonitis:Antimicrobial therapy is started preferably with or just before reoperation, and is aimed at the usual pathogens, Bacteroides fragilis and enterobacteriaceae. A combination of nitro-imidazole and aminoglycoside or 3rd generation cephalosporin appears suitable in most cases. Harbath.S. et al recommend routine coverage for enterococci also in patients with post-operative peritonitis5.  Sitges-Serra et al suggest that only triple therapy including a beta lactam agent along with cephalosporins, aminoglycosides and an anti aerobic agent,  or monotherapy with piperacillin-tazobactam (4gm 8 hourly)would afford optimal coverage against enterococci6.

In my practice, whenever, in a tight spot in a post-operative patient, specially in cases where extensive laparoscopic adhesiolysis  has been performed, if the patient starts getting high temperature, the patient is usually started on amikacin along with magnamycin.  In special cases where, extensive adhesions have been released, there is always a possiblity of inadvertent pricks to the intestine. In such patients and in patients who do not do well on magnamycin, by way of showing high grade fever or rapid pulse or increased respiratory rate, I usually start them on piperacillin-tazobactum combination. If the surgery has gone well it may look like overkilling to give expensive antibiotics to patients, but probably, taking such a stand may be more useful in the set up that we work in, to prevent the patient from going into toxic shock. This is specially so since hospital aquired infections are usually resistant to antibacterials that are routinely used in the hospital. 

Tertiary peritonitis:Laparotomy after prolonged laparoscopic adhesiolysis of bowel, difficult abdominal hysterectomy for higher grades of endometriosis, or even seemingly uncomplicated LSCS can sometimes culminate in septic shock.  Some of these are due to tertiary peritonitis.  Here, the peritonitis and sepsis may have been controlled during surgery and the bacteria eliminated by successful antibiotic therapy. These patients sometimes go into a state in which a syndrome of continued systemic inflammation is produced. There is a hyperdynamic cardiovascular state, low-grade fever and general hypermetabolism. The patient has the clinical picture of sepsis without radiographically demonstrable infection4. Such patients sometimes are subjected to laparotomy seeking to provide drainage of anticipated recurrent or residual collections of infected fluid. On operation, no localized infection is identified. Management is generally supportive and any identified micro-organisms should be treated.

Intra abdominal infections other than diffuse peritonitis3:

In the absence of physical findings of diffuse peritonitis, diagnostic imaging with either computed tomography (CT) or ultrasound should be routinely performed in patients with clinically suspected intra-abdominal infection. The evaluation whould be done within hours.  If there is a collection of pus, it may be better to drain the pus percutaneously without a laparotomy, as manipulation of the bowel in the presence of an intraabdominal infection is usually followed by deterioration in the patient’s condition initially.  Usually, a well established fluid collection (e.g: infected haematoma forming pus) can be drained percutaneously, provided there is a safe access to drain it.Drainage could be performed following fine needle (18–22 gauge) aspiration, with the aspirate being used to document infection and gauge the viscosity of the fluid. For most collections, a drain should be placed to ensure complete evacuation and minimize the chance of recurrence.

Septic shock:

Recent evidence describes sepsis as having two distinct stages. In the early stage, there is an increase in inflammatory mediators, but as sepsis progresses, there is a trend toward an anti-inflammatory immunosuppressive state.  Manifestations of sepsis include tachycardia, tachypnea, alterations in temperature, and leukocytosis. Severe sepsis is manifested by hypoperfusion (eg, lactic acidosis or oliguria), organ dysfunction, or hypotension (septic shock)6 . The organ systems commonly affected include the heart, kidneys, lungs, liver, coagulation system, and central nervous system. Problems may manifest as myocardial dysfunction, acute renal failure, adult respiratory distress syndrome, hepatic failure, disseminated intravascular coagulation, and mental status changes, respectively. Mortality rates with septic shock range from 20% to 80%  .

Septic shock in obstetric patients is usually associated with four specific infections: septic abortion, acute pyelonephritis, and severe chorioamnionitis or endometritis.The most common organisms responsible for septic shock are the aerobic gram-negative bacilli, principally E. coli, Klebsiella pneumoniae, and Proteus species.  In the early stages of septic shock, patients usually are restless, disoriented, tachycardic, and hypotensive. Although hypothermia is occasionally present, most patients have a relatively high fever (39° to 40°C). Their skin may be warm and flushed due to an initial phase of vasodilation (warm shock). Subsequently, as extensive vasoconstriction occurs, the skin becomes cool and clammy. Cardiac arrhythmias may be present, and signs of myocardial ischemia may occur. Jaundice, often due to hemolysis, may be evident. Urinary output typically decreases, and frank anuria may develop. Spontaneous bleeding from the genitourinary tract or venipuncture sites may occur as a result of disseminated intravascular coagulation (DIC). ARDS is a common complication of severe sepsis and is associated with manifestations such as dyspnea, stridor, cough, tachypnea, and bilateral rales and wheezing7.

Management:

1.Any source of infection should be identified and removed.  For women with an infected abortion the uterine contents must be removed promptly by curettage. . Hysterectomy is seldom indicated unless gangrene sets in. With pyelonephritis,  ureteral catheterization, percutaneous nephrostomy or flank exploration may be life saving. 

2.Antibiotics: Choice of antibiotic should ideally be dictated by epidemiologic and hospital data, which is not always available in the Indian set up. 

Recommended antimicrobial regimens for high-risk patients with intra-abdominal infection8:

Single agents:

1.Imipenem/cilastatin

2.Meropenem

3.Piperacillin/tazobactam

Combination therapy

1. Aminoglycoside (amikacin, gentamicin, netilmicin, tobramycin) plus an anti-anaerobe (clindamycin or metronidazole)

 2.Aztreonam plus clindamycin

 3.Ciprofloxacin plus metronidazole

 4.Third/fourth generation cephalosporin (cefepime, cefotaxime, ceftazidime, ceftizoxime, ceftriaxone) plus an anti-anaerobe (clindamycin or metronidazole)

Genital tract infections6:For genital tract infections, the following drugs may be chosen:

Combination reginens:

a.penicillin (5 million units IV every 6 hours) or ampicillin (2 g IV every 6 hours) plus clindamycin (900 mg IV every 8 hours)

b.metronidazole (500 mg IV every 12 hours) plus gentamicin (1.5 mg/kg IV every 8 hours or 7 mg/kg ideal body weight IV every 24 hours)  or aztreonam (1 to 2 g IV every 8 hours)

 Single agents:

a.. imipenem-cilastatin (500 mg IV every 6 hours)

b.meropenem (1 g every 8 hours).

 

Correction of hypotension:Large fluid deficits can exist in septic shock due to external (e.g., diarrhea, sweating) or internal (e.g., edema, peritonitis) losses. a.Fluid resuscitation may consist of natural or artificial colloids or crystalloids. There is no evidence-based support for one type of fluid over another9.

b.Fluid challenge in patients with suspected hypovolemia (suspected inadequate arterial circulation) may be given at a rate of 500–1000 mL of crystalloids or 300–500 mL of colloids over 30 mins and repeated based on response (increase in blood pressure and urine output) and tolerance (evidence of intravascular volume overload). Fluid challenge is a term used to describe the initial volume expansion period in which the response of the patient to fluid administration is carefully evaluated. During this process, large amounts of fluids may be administered over a short period of time under close monitoring to evaluate the patient’s response and avoid the development of pulmonary edema.

Fluid challenges require the definition of four components: 1) the type of fluid to be administered (e.g., natural or artificial colloids, crystalloids), 2) the rate of fluid infusion (e.g., 500–1000 mL over 30 mins), 3) the end points (e.g., mean arterial pressure of >70 mm Hg, heart rate of <110 beats/min), and 4) the safety limits (e.g., central venous pressure of 15 mm Hg).

 With vasodilation and ongoing capillary leak, most patients require continuous aggressive fluid resuscitation during the first 24 hrs of management. Input is typically much greater than output, and input/output ratio is of no utility to judge fluid resuscitation needs during this time period.c.Human albumin may be used when considered appropriate, notably in hypoalbuminemic patients.

d.Blood transfusion should be cautiously given as it may be assossiated with increased mortality.  Patients can tolerate and may even benefit from hemoglobin levels lower than the traditional 10 g/dL

e.If hypotension and organ hypoperfusion do not respond to volume infusion, then inotropic drugs (to improve cardiac performance) and vasopressor therapy (for hypotension) are indicated.

Dopamine or norepinephrine is recommended as the first-line drug10.

 End point of treating hypotension is restoration of central venous pressureto 8-12mmHg, mean arterial pressure 65-90Hg and central venousoxygen saturation >70% .

Adjuvant management:

a.Core temperature should be maintained as close to normal as possible by use of antipyretics and a cooling blanket.

b.Coagulation abnormalities should be identified promptly and treated by infusion of platelets and coagulation factors, as indicated.

c.Patients should be given oxygen supplementation and observed closely for evidence of ARDS, one of the major causes of mortality in cases of severe sepsis.Oxygenation should be monitored by means of a pulse oximeter or radial artery catheter. At the first sign of respiratory failure, the patient should be intubated and supported with mechanical ventilation.

d. Daily haemodialysis or continuous venovenous haemofiltration should be used in patients with overt acute renal failure. 

Newer modalities of therapy10:

1.Use of steroids in septic shock has been controversial.  A meta-analysis showed that hydrocortisone in doses from 200-300mg for 5 days or more reduced duration of shock, systemic inflammation, and mortality without causing harm Only patients with refractory septic shock and adrenal insufficiency benefit from hydrocortisone and 50 micrograms /day oral fludrocortisone can be added.

2. Vasopressin replacement therapy in doses ranging from 0.01-0.04IU/min improved haemodynamics and decreased catecholamine requirements.  However,vasopressin might induce myocardial, cutaneous, or mesenteric vasoconstriction.

3.Recombinant human protein C (detrecogin alfa,24microgram/kgper h for 96h provided a 6% reduction in 28-day mortality from sepsis with at least one recent (<48h)  organ dysfunction.(eg.,acute lung injury or acute respiratory distress syndrome  or acute renal failure).  There should be no risk of bleeding.  One large study on this drug was prematurely stopped because it was found inefficient.  This drug is available locally as “Xigris”.I have adminstered this drug to a septicaemic patient referred to my centre with multiple organ failure following sepsis, but she lost her life.

4. Use of polyvalent intravenous immunoglobulins were found to reduce mortality in studies, but high quality trials found no evidence that immunoglobulins were beneficial. 

Morbidity following septic shock: There may be long term sequels like physical disability related to muscle weakness and post-traumatic stress disorders. 

Bibliography:

1.Orr.JW Jr,HollowayRW,et al, Pulmonary Complications: Complicatins in gynaecologic  surgery: Prevention, Recognition and Management ed:JamesW.Orr Jr and HughM   Shingleton;J.B.Lippincott Company, Philadelphia, 1994.

2..Jimenez.JC,WilsonSE., Prophylaxis of infection for elective colorectal surgery: Surg Infect 4(3):273-280, 2003. © 2003 Mary Ann Liebert, Inc.

3.Burke.T.W, Levenback.C: Complications in gynaecologic Surgery: Prevention, Recognition, and Management, ed:Orr.J.W,Shingleton.H.M, J.B..Lippincott Co, Philadelpia,1994 and Intraabdominal abscesses: Cohen & Powderly: Inf. Dis, 2nd ed., copyright 2004 Elsevier.

4.HarbarthS.UckayI: Are there patients with peritonitis  who require empiric therapy for enterococcus? Eur J Clin Microbiol Infect Dis. 23(2):73-7, 2004 Feb.

5.Sitges-SerraA,Lopez.J,et al: Postoperative enterococcal infection after treatment of complicated intra-abdominal sepsis: Br. J. Surgery: vol89,Iss 3,page361:March 2002.

6.Gainer.JA,YostNP,Critical care infectious diseaseObs and Gyn Clinics

Vol30 • NO4 • Dec 2003 © 2003 W. B. Saunders Company.

7.Gabbe: Obstetrics - Normal and Problem Pregnancies, 4th ed., Copyright © 2002 Churchill Livingstone, Inc.

8.MarshallJC,InnesM,Intensive care unit management of intra-abdominal infection:Critical Care Medicine

Volume 31 • Number 8 • August 2003

Copyright © 2003 Lippincott Williams & Wilkins.

9.Vincent.JL,GerlachH:Fluid resuscitation in severe sepsis and septic shock: An evidence-based review: Critical Care Medicine:Vol32 • O11 • Nov 2004 © 2004 Lippincott Williams & Wilkins

10.AnnaneD,CavaillonJ: Septic shock www.thelancet.comVol365 Jan1,2005.

 

 

 

 

 

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