Fluid Resuscitation in Septic Shock

Dr. Perz,

Boyd, J.H., Forbes, J., Nakada, T., Walley, K., Russell, J.A. Fluid Resuscitation in septic shock: A positive fluid balance and elevated central venous pressure are associated with increased mortality. Critical Care Medicine: Volume 39, Issue 2 (Feb 2011).

The objective of this study was to determine when central venous pressure (CVP) and fluid balance after resuscitation for septic shock are associated with mortality by doing a retrospective review of the use of IV fluids during the first 4 days of care.  The study concluded that a more positive fluid balance both early in resuscitation and cumulatively over four days is associated with an increased risk of mortality in septic shock.  CVP may be used to gauge fluid balance <12 hours into septic shock but becomes an unreliable indicated of fluid balance thereafter.  The study referenced a VASST study (Vasopressin in Septic Shock Trial), which noted that optimal survival occurred with a positive fluid balance of approximately 3L at 12 hours.

This study was a retrospective review of 778 patients from the VASST, all of whom were in septic shock and receiving at least 5mcg of norepinephrine per minute; they analyzed whether a positive fluid balance in the first 12 hours of resuscitation and during the next 4 days was associated with an increase in 28-day mortality. Using the Surviving Sepsis guidelines from 2008, the study grouped patients into those who fell into the recommended range (CVP = 8-12), those with CVP < 8 and those with a CVP >12 and analyzed whether a CVP of 8-12 had a survival advantage.  In this VASST, the patients at 12 hours with a CVP <8 had a lower mortality over those with CVPs of 8-12 and those with CVPs >12.  However, the study also concluded that there is a point when too little fluid is also detrimental.  It also concluded that CVP may be useful along with other measures to gauge adequacy of fluid resuscitation <12 hours into septic shock but becomes an unreliable marker of fluid balance thereafter.  Optimal survival in the VASST study occurred with a positive fluid balance of appx. 3L at 12 hours.  

Anesthetic implications of necrotizing fasciitis

Dr. Belous

AANA journal. 71, no. 1, (2003): 37

This is a review article. It focuses on the issue of anesthesia for cases of necrotizing fasciitis. There are several key considerations to keep in mind. Untreated cases often present as septic shock requiring vasoactive drug administration. Mortality can be as high as 20 to 50 %. These patients definitely require some form of invasive monitoring of hemodynamics and vigorous volume resuscitation. Infected dead tissue tends to bleed and blood products should be readily available. Clotting factor deficiencies may also need replacement. As a rule, multiple surgeries will be required and should be prepared for. In some severe tracheostomy may be indicated along with ICU care. These patients will require pain management, physical therapy and often psych consultations. Intraoperatively, anesthesia provider should be prepared to deal with large fluid shifts, hemodynamic instability, and frequent positioning changes, as well as the use vasoactive drugs.

Neuraxial Anesthesia and Surgical Site Infection, Dr. Chang

Helen A. Chang, DO

Article:
Neuraxial Anesthesia and Surgical Site Infection

Sessler, Daniel I. M.D. Anesthesiology. Aug 2010 – Vol 113 – Issue 2, pp 265-267

Summary:

There is no 100% full proof method to avoid or prevent surgical site related infections. However, this article presents several methods from the anesthesia perspective that may wholly reduce surgical-specific infections. Three methods mentioned: induced hypothermia which reduces tissue oxygenation and thus impairs various immune functions; supplemental oxygen that increases FiO2 halves infection risk (although other studies show no difference) and enhances host defense against bacteria; and considering erythrocyte-based blood products stored less than 2 weeks.

The crux of the article mentioned utilizing neuraxial (i.e. spinal) versus general anesthesia, when clinically/surgically appropriate.  Three mechanisms supporting this theory included: reducing infection by vasodilation and improvement of tissue oxygenation; moderation of the inflammatory response and cascade markers to surgery; and hindering postoperative pain and thereby controlling the autonomic response. The remainder of the article proposes some details on how the study would be optimal to conduct with legitimate subjects and decreased bias.