D T Gleeson | PubMed Health

PubMed2000

A micropower dry-electrode ECG preamplifier.

This paper describes the development of a very low-power preamplifier intended for use in pasteless-electrode recording of the human electrocardiogram. The expected input signal range is 100 microV-10 mV from a lead-II electrode configuration. The amplifier provides a gain of 43 dB in a 3-dB bandwidth of 0.05 Hz-2 kHz with a defined high input impedance of 75 M omega. It uses a driven common electrode to enhance rejection of common-mode interfering signals, including low-frequency motion artifact, achieving a common-mode rejection ratio (CMRR) of better than 80 dB over its entire bandwidth. The gain and phase characteristics meet the recommendations of the American Heart Association, ensuring low distortion of the output ECG signal and making it suitable for clinical monitoring. The amplifier has a power consumption of 30 microW operating from a 3.3-V battery and is intended for use in small, lightweight, portable electrocardiographic equipment and heart-rate monitoring instrumentation.

Artifacts↗

PubMed1994

Premixed insulin preparations in pen syringes maintain glycemic control and are preferred by patients.

OBJECTIVE: To examine the impact on glycemic control of substituting a range of premixed insulins for the standard treatment with patient-mixed insulin combinations. In addition, a pen-type syringe was substituted for the conventional insulin syringe, and the patients' preference was ascertained at the end of the study. RESEARCH DESIGN AND METHODS: Before the study, all patients had maintained a constant insulin dosage for 2 months. For the first month of the study, all patients were encouraged to make any adjustment in insulin dosage required to optimize control. Twenty-seven patients participated in the study. At the end of the first month, patients were randomized either to change to premixed insulins or to continue with self-mixed insulins for 2 months. At the end of the 2-month period, participants changed to the alternative regime for a further 2 months. Glycemic control was measured by assessment of glycosylated hemoglobin levels at the start of the study and after each 2-month period of the study. In addition, during the 1-month run-in period and during both 2-month study periods, a seven-point blood glucose profile was obtained extending from before breakfast to just before retiring for sleep. RESULTS: Glycosylated hemoglobin levels were unchanged throughout the duration of the study. Similarly, there were no systematic changes in individual seven-point blood glucose profiles. The frequency of hypoglycemic reactions was similar on patient-mixed and premixed insulin programs. However, 83% of patients expressed a preference for premixed insulins. A similar percentage regarded pen-type insulin syringes to be preferable to the conventional syringe. CONCLUSIONS: Glycemic control was similar on patient-mixed and premixed insulins, and patients had a marked preference for premixed insulins delivered in a pen-type syringe over conventional insulin therapy. Premixed insulin delivered by a pen-type syringe promises to ease the burden of daily injections for many diabetic patients.

Adolescent↗