Skip to main content

Pre-optimisation of surgical patients.


There have been a number of publications looking at the pre-operative optimisation of oxygen delivery for high risk patients. They are based on studies showing that high-risk patients surviving major surgery achieved consistently higher postoperatrive oxygen delivery and cardiac index compared with non-survivors.

Shoemaker showed the following values to be associated with survival:
Cardiac Idex (CI)                    4.5 l/min/m2
Oxygen delivery (DO2)            600 ml/min/m2
Oxygen consumption (VO2)     170 ml/min/m2

Shoemaker et al. in 1987 and Boyd et al. in 1993 showed that producing supranormal values of oxygen delivery(>600 ml/min/m2) resulted in a reduction in pot-operative mortality in high risk surgical patients.

A paper in Critical Care Medicine in 2000 (prospective, randomized controlled trial of 412 patients undergoing major abdominal surgery in 13 hospitals from 6 European countries) compared the effects on morbidity/mortality of dopexamine infusion or placebo on fluid resuscitated patients. Patients were taken to ICU pre-operatively, invasive monitoring inserted and fluids given until set criteria met. Randomization to dopexamine 0.5 mcg/kg/min, 2 mcg/kg/min or placebo followed. There was no statistically significant difference in 28-day mortality in the three groups, although the authors speculated a trend towards lower mortality in the low-dose dopexamine group.

Consensus meeting: management of the high-risk surgical patient, April 2000
-Increasing global oxygen delivery in high risk patients significantly reduces mortality.
-In patients with significant IHD, care needs to be taken to minimize oxygen demand.
-The earlier the intervention, the better the outcome.
-Strategy should be as defined by shoemaker's criteria for CI, DO2, and VO2.
-Low dose dopexamine may have additional benefits.

A meta-analysis of fluid optimization by Kern and Shoemaker in Critical Care Medicine in 2002 concluded that patients at high risk (predicted mortality >20%) would benefit from fluid optimization but not those with a predicted mortality <15%.

On the flip side of the coin, excessive fluid resuscitation has been shown to worsen outcome in abdominal surgery (Brandstrup et al. 2003)


Labels:

Comments

Post a Comment

Popular posts from this blog

The pressure volume loop...

In the pressure-volume loop below, cardiac work is best represented by:   the area of the curve  the slope of the line from points C to D  the distance of the line from points C to D  the slope of a line from points A to D .. .. ... .... ... .... .... .... In the pressure-volume loop below, cardiac work is best represented by:  the area of the curve Cardiac work is the product of pressure and volume and is linearly related to myocardial oxygen consumption. Cardiac work is best represented by the area of the curve of a pressure-volume loop.
Post a Comment
Read more

Anaphylaxis updates part 2- Empty Ventricle Syndrome

Patients with anaphylaxis should not suddenly sit, stand, or be placed in the upright position. Instead, they should be placed on the back with their lower extremities elevated or, if they are experiencing respiratory distress or vomiting, they should be placed in a position of comfort with their lower extremities elevated. This accomplishes 2 therapeutic goals: 1) preservation of fluid in the circulation (the central vascular compartment), an important step in managing distributive shock; and 2) prevention of the empty vena cava/empty ventricle syndrome, which can occur within seconds when patients with anaphylaxis suddenly assume or are placed in an upright position. Patients with this syndrome are at high risk for sudden death. They are unlikely to respond to epinephrine regardless of route of administration, because it does not reach the heart and therefore cannot be circulated throughout the body
Post a Comment
Read more

Steroids In Perioperative period...The Multi-purpose Drugs

1-Steroids are not Bronchodilator ,but have well established usefulness in hyper-reactive airway. They are also said to have a permissive role for bronchodilator medication. They can be administered orally, parenterally or in aerosol form 2- Steroids have been commonly used in chemotherapy for prevention of nausea along with other anti-emetic agents . Dexamethasone was found to be highly effective when given immediately before induction rather than at the end of anesthesia . 3- Steroids do exert analgesic effects. Various routes of administration of steroids include parentral, local infiltration at operated site , as an adjuvant in nerve blocks and central-neuraxial blockade. 4 - Steroids cannot be the mainstay of therapy in anaphylaxis because of the delayed onset of action, so they are used as adjunct after initial treatment with epinephrine. 5- Steroids (Dexamethsone) are of value in reduction or prevention of cerebral edema associated with parasitic infections and neopla...
1 comment
Read more