Two Glycemic Control Algorithms Compared

Dr. T. Chon

The comparison of two glycemic control algorithms for postoperative surgical patients

  

A Novel Computerized Fading Memory Algorithm for Glycemic Control in Postoperative Surgical Patients

Mayumi Horibe, MD,*† Bala G. Nair, PhD,* Gary Yurina, CRNA,† Moni B. Neradilek, MS,‡ and Irene Rozet, MD*†

Anesthesia & Analgesia June 2012

Hyperglycemia is an important predictor of morbidity and mortality, especially in critically ill patients. This study compared the use of a “Fading Memory” algorithm (FM) and an established algorithm (VA) used at their institution. The innovative FM algorithm was designed to mimic the pancreatic cell response of an initial, transient/rapid increase in insulin, then a slower increase of insulin that remains elevated for the duration of hyperglycemia. The study used Regular Insulin infusion and used target goals as 140 +/- 20mg/dl. Four comparisons were made between the two algorithms; the 1) time to reach the target glucose level and, 2) glucose level within target range during maintenance were not statistically significant; whereas the 3) the ability to maintain glucose levels with minimal variability and, 4) mean insulin dosage used in the maintenance phase was found to be statistically significant. The use of the FM algorithm is a helpful addition to the various debates/studies with glucose control. One of the strengths of this study is selecting a target glucose range that was not too low, avoiding hypoglycemia. In the future, the FM algorithm should be studied during the intraoperative setting and applied to patients with other co-morbidities such as end-stage renal disease and/or patients with greater insulin resistance, such that is seen in our county population.

Update on Transfusion Medicine

Dr. T. Chon

Anesthesiology. Goodhough LT, Shander A. 2012 June;116(6):1367-1376. Patient Blood Management

It is the collaboration of a multidisciplinary team consisting of transfusion medicine specialists, surgeons, anesthesiologists, and critical care specialist to optimize the appropriate use of blood and blood components for patients when needed. Multiple steps are outlined to guide clinicians the decision to transfuse keeping in mind the risks of exposing the patient to known blood risks, unknown blood risks, preservation of the national blood inventory, and constraints from escalating costs. The multimodal decision to transfuse are based on, but not limited to, 1) appropriate anemia management and work-up in the pre operative setting; 2) blood availability and compatibility testing; 3) blood administration and documentation; 4) alternatives to allogeneic blood; and 5) indications for blood transfusion.

A thorough anemia workup must be complete before (at least 30days) scheduled elective surgery. Anemia can be due to iron deficiency secondary to occult blood loss or malignancy, chronic inflammation, chronic kidney disease, Vitamin B12/Folic acid deficiency.

If the patient is suspected to undergo transfusion, preparation must include a completed type and screen/cross. To ensure availability of the blood products, clinicians should confirm that the appropriate blood work is completed before proceeding to the operating room.

In order to decrease error of blood product administration, blood products must have a patient identification with transfusion order confirmed, date and time of transfusion, and vitals before and after transfusion.

To help with decreasing the introduction of allogeneic blood, autologous transfusions are a good option for patients, but not without risks. In preoperative autologous donation, patients donate their own blood over a period of weeks, but risks include acquired storage lesions, depletion of 2,3-DPG, and impaired ability for erythrocytes to unload oxygen to tissues. Acute normovolemic hemodilution allows preoperative dilution of blood loss, most effective in procedures with large blood loss, but efficacy on its use is mixed due to low acceptance secondary to the lack of standardized protocols, variations in target hemoglobin, types of fluids used, heterogeneity in surgical blood losses by procedure, and patient selection criteria. Lastly cell salvage helps with the reduction of allogeneic blood transfusions but can increase loss of platelets and plasma in washed blood leading to dilutional coagulopathy or thrombocytopenia, and is a relative contraindication in patients with cancer or obstetric/bowel surgeries involving contamination.

Consensus for blood transfusion has been debated, using hemoglobin levels as a threshold.

Generally, transfusion is not of benefit when hemoglobin is greater than 10 g/dl, and are beneficial when less than 6 g/dl. Multiple trials show that patients can tolerate hemoglobin between 7 and 8 g/dl, with equivalent clinical outcomes, and a higher threshold for elderly patients with coronary risks undergoing surgery with anticipated blood loss.

Blood transfusions are at times necessary but do carry risks. The decision to transfuse must be based on a thorough workup, preparation, alternative options, and optimization of patient safety