Treatment of diabetic ketoacidosis with a computer-controlled bedside monitoring and infusion system.

A metabolic monitoring system is described that allows the simultaneous and automatic in vivo analysis of the metabolic parameters glucose, pH, and pCO2 as well as the computer-controlled automation of the possible necessary infusion therapy. This bedside system has proved to be useful in treating acidotically and non-acidotically decompensated diabetes mellitus. Our experience with this system is as follows: 1. quick correction of the acidosis without danger of alkalosis, 2. shorter period of treatment, 3. considerably reduced insulin requirement, 4. no danger of hypoglycemia, and 5. minimum net blood withdrawal (1.2 ml/h). The efficiency of this system is demonstrated by examples.     

Computer-controlled direct scanning gel chromatography system

We have developed a system for direct scanning gel chromatography which is under direct control of a SYM-1 microprocessor which is in turn under control of a PDP 1104. Each scan consisting of ～200 data points of a 20-cm column may be obtained in as little as 3.5 s. Up to 100 scans may be obtained automatically without operator attention. A series of data manipulation programs have been written to allow determination of centroid migration rates, time difference chromatography calculations, etc. In conjunction with a mass transport simulation program it is possible to rapidly fit observed chromatography profiles. Use of the system to determine dispersion coefficients is described.     

A portable near infrared spectroscopy system for bedside monitoring of newborn brain

Background  

Newborns with critical health conditions are monitored in neonatal intensive care units (NICU). In NICU, one of the most important problems that they face is the risk of brain injury. There is a need for continuous monitoring of newborn's brain function to prevent any potential brain injury. This type of monitoring should not interfere with intensive care of the newborn. Therefore, it should be non-invasive and portable.     

Single-mouse urine collection and pH monitoring system.

A glass cage with minimal surface area was designed and used to house mice for 24-hour urine collections. An experiment was performed with a radio-labeled compound excreted in the urine to assess the collection efficiency of the cage. In this experiment 74.2 +/- 6.5% of the excreted radioactivity was recovered in the urine, with 25.8 +/- 6.5% found adhering to the cage surfaces. When a flow-through pH electrode, meter, and recorder were attached, the system provided a continuous pH versus time urination record.     

Computer-controlled pulse modulation system for analysis of photoacoustic signals in the time domain

A newly developed photoacoustic system for measurement of photosynthetic reactions in intact leaves is described. The system is based on pulsed light-emitting diodes, the pulse program and pulse response analysis being computer controlled. Separation of various components in the overall photoacoustic signal is achieved by curve fitting analysis of the responses following individual measuring light pulses in the millisecond time domain. This procedure is in distinction to the conventionally used analysis in the frequency domain, with the advantage that various signal components are obtained by on-line deconvolution, yielding simultaneous recordings of photothermal (complement of energy storage) and photobaric (evolution and uptake) signals. The basic components of the new system are described by block diagrams and the principal steps for deconvolution of the overall photoacoustic response are outlined. An example of application with simultaneous recording of chlorophyll fluorescence is given. It is apparent that the photobaric uptake component represents a significant part of the overall signal, particularly during induction of photosynthesis after dark-adaptation. This component probably contains not only O₂-uptake but uptake of CO₂ as well.Abbreviations PA photoacoustic - LED light-emitting-diode - RAM random access memory     

Preprogrammed insulin infusion with a portable pump system.

A glucose-controlled insulin infusion system (Biostator) was used to determine patient insulin requirement for clinical evaluation of a portable pump system (technical development by Siemens AG). Results from 6 insulin-dependent diabetics with respect to quality of control, carbohydrate/insulin ratio, and insulin requirement are shown. Preprogrammed insulin infusion with the portable system was carried out for up to 117 days.     

Evaluation of the quality of bedside monitoring of the blood glucose level in a teaching hospital.

We evaluated the precision and accuracy of monitoring of the blood glucose level in the laboratory and at the bedside with one of four glucose meters by an experienced operator and by 39 nurses in a teaching hospital. For precision studies aqueous quality control materials were used. A total of 85 blood samples were tested. The precision of the glucose meters (expressed as the coefficient of variation [CV]) in the hands of the experienced operator ranged from 6.7% to 11.1%. The correlation between the values obtained by the experienced operator and the reference values obtained in the laboratory was high (0.95 to 0.98). The precision of the values obtained by the nurses using the meters ranged from 13.7% on medical wards to 45.7% in the intensive care unit (ICU). The correlation between these values and those obtained in the central laboratory ranged from 0.72 to 0.82. Twenty-four percent of the glucose values determined on medical wards and 62% of those determined in the ICU deviated from the reference value by at least 20%. Of the 85 patients 12 (14%) would have received different insulin dosages had the reference value been available at the same time as the glucose meter reading: in 3 of the patients the discrepancy was 6 units of insulin or greater. Continuous quality control of bedside monitoring of the blood glucose level is needed. In addition, personnel who use glucose meters should receive adequate training.     

Closed-loop system in evaluation of insulin infusion rates for an open-loop system.

The daily insulin requirements as calculated with a closed-loop system (Biostator), were used for insulin infusion with a portable, miniaturized pump in 6 juvenile-onset, insulin-requiring diabetics. Three diabetics were given insulin in a manner like that of the Biostator, e.g., maximal insulin infusion about 1 hour after start of meals. The MBG was 8.7 +/- 3.9 (SD) mmol/l. Three other diabetics had insulin in a fixed profile with peaks beginning simultaneously with meals. MBG of these patients was 4.4 +/- 1.9 mmol/l. Knowing the daily insulin dosage as calculated from the Biostator, normal blood glucose levels can be achieved with a fixed profile of insulin given by a portable pump.     

A surgical procedure and tethering system for chronic blood sampling, infusion, and temperature monitoring in caged nonhuman primates

A jacket and tethering system was used to maintain chronic catheters in monkeys, which provided catheter access and manipulability without further restraint. Surgical placement of catheters and a temperature probe allowed for a common cutaneous exit and interface with the jacket and tether. Monkeys were fitted in a sterile leather or denim jacket which was attached to a sterilized flexible stainless steel cable. Through this conduit, an indwelling temperature probe, as well as catheters from the internal jugular and femoral veins, were attached to a swivel unit located on the upper portion of the cage. The internal jugular catheter was used for the continuous infusion of support solution. The catheter from the femoral vein was maintained with a heparin lock and used for serial blood sampling. Using this system, it was possible to obtain frequent blood samples and body temperature readings, and to administer a continuous intravenous infusion without chemical or excessive physical restraint. To date, 367 monkeys, 322 cynomolgus (Macaca fasicularis), 16 rhesus (Macaca mulatta), and 21 African green (Cercopithecus aethiops) have been studied using this procedure.     

A computer system for neurosurgical patient monitoring.

The variables monitored in intensive care units are generally late indicators of neurologic deterioration. A system based on a LINC-8 computer was therefore developed for on-line monitoring of evoked potentials, electroencephalography (EEG), and transcranial and transthoracic impedances as well as conventional parameters. Somatosensory evoked potentials are recorded at either 30 min or 1 h intervals. One minute epochs of EEG are analyzed every 10 min using a peak-detection algorithm. Impedances and conventional parameters are also monitored at 10 min intervals. In a study of 50 patients, the technical feasibility of this type of monitoring with a small laboratory computer has been demonstrated. In some instances, evoked potentials and EEG show changes prior to detectable neurologic changes. The study suggests that this type of monitoring can provide a valuable adjunct for evaluation of physiologic function in neurosurgical intensive care.     

The US national antimicrobial resistance monitoring system.

The use of antimicrobial agents in food animals can select for resistant bacterial pathogens that may be transmitted to humans via the commercial meat supply. In the USA, the FDA's Center for Veterinary Medicine regulatory duties require a determination that antimicrobial drugs are safe and effective for use in food animals. In addition, a qualitative assessment of risks to human health from antimicrobial resistance requires development. This risk assessment process is supported by data generated by the FDA's National Antimicrobial Resistance Monitoring System (NARMS) for enteric bacteria. NARMS data on antimicrobial susceptibility among Salmonella, Campylobacter, Escherichia coli and Enterococcus is collected. Research activities defining the genetic bases of resistance helps to understand the potential public health risks posed by the spread of antimicrobial resistance from food animal antimicrobial use. These activities help insure that antimicrobials are used judiciously to promote human and animal health.     

A fiberoptic sensor system for cardiac monitoring and electrotherapy.

Commercially available cardiac pacemakers and implantable cardioverters/defibrillators (ICD) predominantly use the intracardiac derived electrocardiogram (ECG) for detection of arrhythmias. To achieve an automatic control of the heart frequency in accordance with cardiovascular strain and an improved detection of life-threatening arrhythmias, it is desirable to monitor the heart by an input signal correlated with the hemodynamic state. One possible approach to derive such a signal, is to measure the inotropy (mechanical contraction strength of the heart muscle). For this purpose an optoelectronic measurement system has been designed. The fundamental function of the system has been shown in earlier investigations using an isolated beating pig heart. In this paper further results showing the correlation of the fiberoptic sensor signal with the left ventricular stroke volume are presented. To make the system useful for implantable devices, further improvements with regard to power consumption and signal quality were achieved.     

Clinical application of pre-programmed insulin infusion: continuous subcutaneous insulin therapy with a portable infusion system.

Strict control of blood glucose was achieved by continuous subcutaneous insulin infusion with a specially adapted Mill Hill Infuser for 3-4 days. This led to normalisation of some of the intermediary metabolites. In a few patients, subcutaneous infusions have been carried out for periods up to 3 months with home monitoring of blood glucose, without infection or lipodystrophy. Short-term improvement of metabolic control was associated with recovery of abnormal renal glomerular permeability to albumin.