Heparin..Part II..Heparin Resistance

Heparin resistance is defined in terms of the context: A) in treatment of VTE, if more than 35,000 u / 24 hour period is required to prolong the aPTT to the therapeutic range, or B) in cardiac bypass surgery, if after heparinization, there is at least one ACT greater than 400 s or if exogenous antithrombin is required.

In general, studies have sited heparin resistance to occur due to a multitude of factors in 22% of patients undergoing major surgery.
AT deficiency only accounts for one possible cause among many including increased clearance of heparin from the plasma, elevations of various heparin binding proteins (as mentioned above), elevations in FVIII and fibrinogen levels. Medications such as aprotinin and nitroglycerin have also been sited as causal of heparin resistance.
In patients previously exposed to heparin or requiring an IABP, resistance may arise. In the surgical population it is likely that when resistance to heparin occurs, it is due to decreased AT activity.

Lemmer JH et al found 85% of patients to have low AT activity, while another group noted the rate to be 77% of those who were heparin resistant. Both of these authors reported that AT concentrate was able to prolong the ACT to the target range in patients found to have below normal AT activity who did not initially achieve the target ACT.

Comments

power injectable peripherally inserted central catheters

Clinical experience with power injectable peripherally inserted central catheters in intensive care patients Introduction In intensive care units (ICU), peripherally inserted central catheters (PICC) may be an alternative option to standard central venous catheters, particularly in patients with coagulation disorders or at high risk for infection. Some limits of PICCs (such as low flow rates) may be overcome by the use of power-injectable catheters . Method We have retrospectively reviewed all the power injectable PICCs inserted in adult and pediatric patients in the ICU during a 12-month period, focusing on the rate of complications at insertion and during maintenance. Results We have collected 89 power injectable PICCs (in adults and in children), both multiple and single lumen. All insertions were successful. There were no major complications at insertion and no episodes of catheter-related blood stream infection. Non-infective complications ...

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.

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...

sedationstation

Search This Blog