17 Nov 2013
November 17, 2013

APS Protocol Theory

0 Comment

Artificial Pancreas System Therapy (APS) is a process which promotes the normalization of carbohydrate metabolism in diabetic patients. APS affects multiple organs, especially muscle, retina, liver, kidney, and nerve endings. The process involves the administration of insulin pulses similar to those found in the portal circulation of normal humans using the Bionica MicroDose which is FDA labeled for this treatment. The process is monitored by frequent glucose levels and respiratory quotients (RQ). RQ is measured by a metabolic cart which determines the ratio of VCO2/ VO2. This ratio is specific for the fuel used at any one time by the body. The glucose levels are monitored to keep glucose levels appropriate, and the RQ determines the need to readjust the infusion. APS is done over 1-hour periods with a ¾ to 1-hour rest period between each session for three courses each day of treatment. Typically, APS is performed on a weekly or bi-weekly basis following the first week of two back-to-back daily sessions.

The following is a typical treatment session:

The patients report to the APS clinic between 7:00am and 8:30am.

• Patient clinical assessment is performed prior to treatment:
• Vital signs.
• Initial glucose level.
• Review of medications.
• Overview of patient’s overall condition.

Following the initial assessment, an intravenous line is established and APS commences.

APS treatment session:
• U / kg of Insulin, pulsed at 10 pulses/hour over 1 hour is administered by the Bionica MicroDose specialty pump programmed for the concentration, frequency and duration of pulses, and rest intervals.
• The respiratory quotient (RQ) or metabolic measurement is performed at the beginning and end of each one hour treatment to measure success
of treatment and adjust the amount of insulin and glucose. Glucose levels are taken every 30 minutes or more frequently as medically indicated in patients with a tendency for hypoglycemia.
• Oral carbohydrates are given to keep blood glucose over 100 mg/dl and to increase RQ. Approximately 100 g of glucose is given, (400 cal.)
• There is a rest period of 40 minutes to one hour between treatments in order to stabilize blood glucose levels.
• This cycle is repeated twice more in a single treatment day.
• Patient is evaluated after the session and discharged when stable.
• Frequent monitoring of respiratory quotient is essential in order to verify patient response to APS treatment. When RQ is low (0.7-0.8), fat is the primary fuel and at RQ’s of 0.9-1.0, glucose is the primary fuel. Protein and mixed fuel utilization have intermediate RQ’s of 0.8-0.9.
• APS increases the respiratory quotient in diabetic patients from levels around 0.7 to levels greater than 0.9. This reflects the underlying physiologic changes of the treatment, confirming the conversion from fat metabolism, typical in the diabetic patient, to a normal metabolic state utilizing carbohydrate as the primary fuel consumed. Both the total amount of insulin contained within each pulse as well as the total amount of consumed glucose is altered in order to maximize treatment results.