Ambulatory Recording System Research Articles

Effect of meal composition and sham feeding on duodenojejunal motility in humans.

The disruptive effect of meals of different fat content and caloric value and of sham feeding on the interdigestive migrating motor complex (IDMMC) was studied in eight healthy subjects using an ambulatory recording system that allowed continuous monitoring of small bowel motility for three consecutive days. The durations of fed pattern were not significantly different between meals of 800 kcal/50% fat, 400 kcal/50% fat, and 800 kcal/25% fat, but were significantly longer compared to IDMMC cycle length and sham feeding. The latter two were not significantly different. On a separate day, five subjects consumed a meal of 400 kcal/9% fat and a second one of 800 kcal/50% fat. The duration of the fed pattern following the high fat meal was significantly longer than the low fat one. Sham feeding significantly increased plasma concentrations of gastrin and neurotensin (NT), but did not affect those of cholecystokinin (CCK), insulin, and peptide YY (PYY). The various variables of the IDMMC were not different during the two nights of the study, and velocity of migration of phase III during the first day and both nights was similar. We conclude that the duration of the fed pattern depends, in part, on the composition of the meal. Sham feeding, resulting in an increase in both plasma gastrin and NT concentrations, does not disrupt the IDMMC. When using thin probes, IDMMC is stable during prolonged recording.

Method for prolonged ambulatory monitoring of high-amplitude propagated contractions from colon

This study monitored high-amplitude propagated contractions (HAPCs) in ambulating subjects over a 24-h period using a new ambulatory recording system. Twelve healthy volunteers aged 34 +/- 5.96 yr participated. Approximately 12 h after a Colyte bowel prep, a small catheter (OD less than 3 mm), containing three solid-state pressure transducers spaced 5 cm apart, was positioned by flexible sigmoidoscope at 40-50 cm from the anal verge. A battery-operated data recorder sampled the pressure at each port at 1 Hz and stored the values on all ports if any port exceeded 75 mmHg. At the conclusion of the 24-h period, an X-ray was taken to confirm the location of the catheter. Fifty-four percent of all HAPCs preceded a bowel movement by less than or equal to 1 h. Forty-nine percent of all HAPCs occurred within 1 h after a high-fat meal, and 33% occurred within 1 h of morning awakening. Reverse propagated waves, not previously described in the colon, were observed in three individuals. Spontaneous high-amplitude caudally propagated contractions occur 6.9 +/- 1.5 times/24 h in the sigmoid colon in ambulating asymptomatic individuals and are temporally related to defecation and meals. Peristaltic activity is decreased during sleep. This recording technique was reliable and well tolerated in all participants.

Conducting a matched-pairs historical cohort study with a computer-based ambulatory medical record system

We describe techniques for using the Computer-Stored Ambulatory Record (COSTAR) at the Massachusetts General Hospital to conduct a historical cohort study of the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on blood pressure control. A query language was used to identify patients satisfying clinical and data-availability criteria, to match these patients with clinically similar patients not exposed to NSAIDs, and to collect data from the COSTAR records of both groups of patients to determine any differences in outcome. We analyzed over 30,000 patient records to select 90 pairs of patients used in the study. This approach to clinical research uses data collected for purposes of patient care and so does not require the separate recording of patient data for clinical research. Using computer-based medical record systems with a query language allows selection and matching of patients using detailed demographic and clinical criteria. The ability to conduct such studies is an advantage of computer-based medical record systems over the paper record system.

Filtering characteristics of ambulatory EEG recording systems

An analysis of the filtering in ambulatory EEG systems is performed. The typical ambulatory EEG system has 3 cascaded time constants each of which distorts the signal. Using a settling time criterion the analysis suggests settings or specifications for the 3 time constants in order to be equivalent to a single overall time constant. The signal distortions due to various settings are illustrated for typical EEG wave forms. It is shown that the distortion can be particularly severe when overload occurs in the ambulatory recording system, a condition that is prevalent due to high amplitude signals such as movement artifact and eyeblink.

Computer Programs to Support Clinical Decision Making-Reply

In Reply.— We agree with Dr Norman that computer-based medical information systems have the potential to improve the quality of medical care. We have also demonstrated that a computer-based ambulatory medical record system (COSTAR) can be used to provide automatic monitoring and feedback that improve physician performance to quality assurance protocols. 1 It should be pointed out, however, that systems such as DXplain have two limitations in improving the quality of care. First, DXplain serves only to remind the physician of plausible diagnoses for a given set of signs and symptoms; the physician must still exercise clinical judgment as to the correct diagnosis. Second, a user of DXplain must enter the signs and symptoms of a given patient into the computer system as a separate and duplicate act, independent of entering the information into a medical record. We believe the full potential of such systems will not be realized until

The Application and Utilization of an Ambulatory Recording System for the Screening of Sleep Disorders

ABSTRACT.It has become apparent in the last few years that many sleep complaints expressed by patients may involve cessation of breathing during sleep (apnea) or severe leg jerks (periodic movements in sleep-PMS), causing brief arousals throughout the night. The most commonly used practice for screening of these two disorders has been an all-night laboratory polysomnogram, which records sleep/wake, respiration, and leg movements. This technique involves, for the patient, a high cost, restriction of movement, and an unfamiliar and sometimes frightening setting. During the last few years our laboratory has used a portable ambulatory recording method to screen for sleep apnea and PMS, establishing a reliable and comfortable screening procedure in the patient's own home. The overall cost of an initial screening is thus reduced, as is the time spent by the technician who, in the laboratory, would monitor the patient all night. This method allows more patients to be screened by one technician and allows easy ap...