Medical Management of Septic Shock
Luis H. Tello, DVM, MS
Small Animal Teaching Hospital, University of Chile
Septic shock is a common complication in small animal practice. Many pathologic conditions can result in spread infection and associated Shock. The overuse of corticoids, immunosuppressive therapies, the wide spread use of IV catheters are some of the reasons that septic shock has become more familiar for Veterinary practitioners.
Shock has been defined as a critical imbalance of cellular energy production because failure in the delivery of oxygen and nutrients to the cell and utilization of oxygen and nutrients by the cell. More than 90% of the energy that the cell spends is about to survive from an aggressive environment. Shock may be result from any syndrome, diseases state, or injury that leads to a critical decrease in effective blood flow to the tissues, leads to derangement in cellular metabolism and ultimately cell death.
Sepsis is defined as the systemic inflammatory response to infection. Therefore systemic inflammatory response syndrome (SIRS) is a complicate syndrome that may occur as a result of trauma, burn, sepsis and is currently defined as patients that show two or more of the following criteria:
In early stages of septic shock (hyperdynamic phase), patients may show dark red mucous membranes with a short capillary refill time (CRT< 1 second), elevated heart and respiratory rate, fever, bounding pulses and signs associated to peripheral vasodilation. In more advanced stages mucous membranes may see grey and dry, Increased CRT, weak pulses. These patients need a Emergency Team approach, because the different procedures and exams that such a patient require.
Data about of septic patients, should be collected to determine if they have any predisposing factor in history as immunosuppressive therapy or chemotherapy, as well metabolic diseases such as Cushing's Syndrome, Diabetes mellitus or viral infections as Parvovirus.
Blood samples should be obtained for culture, complete blood count, prothrombin time, partial thromboplastin time, clinical chemistry panel and blood gas evaluation. In the same way, urine sample must be obtained by centesis for urinalysis and culture.
The aim of treatment in septic shock is care, improve and maximize oxygen delivery to the tissues to address their demands. Two or three largest possible catheter should be placed for fluid administration and if possible, a jugular catheter for assessing central venous pressure.
The adequate fluid and administration rate choice for fluid therapy remains as a very controversial issue. Initially you can start with a crystalloid fluid at 70-90 ml/kg in dogs, 45-60 ml/kg in cats, looking forward a hemodynamic stability (Blood pressure, Capillary refill time, Central Venous Pressure, Good quality and rate Femoral Pulse, Mucous Membrane Color, Peripheral temperature).
If there is not adequate response to therapy, the remainder volume can be given as a colloid such as Haemacell, Dextran or Hetastarch (10-20 ml/kg/day). Therefore, colloids should also be considered if the total protein is less than 3.5 gm/dl. In cats, the best response is achieved with colloid bolus 5-10 ml per cat. If there is a glucose level less than 60 mg/dl, a bolus of 50% dextrose should be given at a volume of 0.5-1 ml/kg, diluted with and equal volume of saline, IV.
If the microorganism source can be identified, samples should be aseptically obtained and submitted for culture and sensitivity. While wait for the culture results, antibiotic therapy should be instituted. Broad-spectrum antibiotics should be selected based on the suspected pathogen organism.
Frequent complications associated to the Septic Shock patients are sepsis and GI ulceration. Use of Famotidine, Ranitidine may help to reduce the risk of ulceration. If there is evidence of hemorrhage, Sucralfate is indicated.
Nutrition is one of the corner stones in septic patients, and enteral nutrition is the best choice to feed both to the patient and to the enterocytes. If the patient does not eat despite adequate GI protective and antiemetic drugs, a nasoesophageal tube can be placed for short-term enteral nutrition. Otherwise, total parenteral nutrition (TPN) is very expensive and does not provide nutritional support of the enterocytes.
Finally, good hospital care is very important for the patient's well being, like prevention of decubital ulcers keeping patients on soft padded surfaces covered with absorbent material to prevent scalding by urine and feces. Catheters must to be checked daily.
Antibiotics and doses recommended in septic patients
1 first, 2 second, 3 third generation
Luis H. Tello, DVM, MS