Biomedical subjects

S T Kalli

Publications and source records attributed to S T Kalli.

3 recordsLinked to original sources

PubMed1991

A data model for intensive care.

The paper describes a model of clinical management data in a typical general intensive care unit, intended as a generic database specification for advanced intensive care computer systems. The data model was developed as part of the INFORM project. The INFORM project is summarised and the relevance of the data model to the objectives of the project are discussed. An object oriented extension to the entity relationship diagram methodology is presented. The methodology is illustrated with reference to some specific aspects of the data model including: the principle clinical entities; classification of patient state related data and the homogeneous patient group system. It is suggested that such a model will contribute to the better understanding of the data in the system, to the better design of future intensive care computer systems and to the setting of standards for medical data.

Decision Support Systems, Management↗

PubMed1991

Do beta-adrenergic blockade and sleep state affect cardiorespiratory control in neonatal lambs? Multivariate autoregressive modeling approach.

Beta-Blockers are used in pregnancy-associated hypertension and in postnatal cardiac arrhythmias, and the neonate may get them in breast milk. We therefore studied the effects of beta-adrenergic medication on interrelations between heart rate (HR), respiration, and arterial blood pressure (aBP) in newborn lambs. The influence of sleep state on these cardiorespiratory interrelations was also examined. HR, aBP, and respiration (based on transthoracic electrical impedance) were recorded and the sleep state was visually documented in five healthy chronically instrumented newborn lambs before the age of 30 d. Propranolol was given (1 mg/kg). Two-min stationary segments of the three signals were analyzed using a multivariate autoregressive model, which yields oscillations of the signals and intersignal relationships as source contributions. The variabilities of aBP and HR were greatest at the low frequencies (less than 0.25 Hz) and so were their intersignal relationships (including baroreflex). The respiratory variability was greatest at the frequencies corresponding to the respiratory rate. During quiet sleep, the variabilities in HR, aBP, and respiration were lowest. The impact of respiratory oscillations on other signals increased but the impact of aBP variability decreased during quiet sleep. beta-Blockade and sleep state affected separately the cardiovascular and respiratory variables and their interrelations. beta-Blockade reduced HR and increased pulse pressure. The overall heart rate variability and the respiratory low-frequency contribution to heart rate variability decreased due to the beta-blockade. We postulate that the beta-adrenergic system is an important regulator of HR and HR variability in neonatal lambs and also of the low-frequency components of the respiratory sinus arrhythmia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Blood pressure level changes caused by posture change and physical exercise: can they be determined accurately using a standard cuff method?

The accuracy of the indirect standard cuff method of measurement was tested against intra-arterial blood pressure readings (Oxford method) in a series of simple clinical tests: in the sitting, supine and standing positions, during bicycle ergometer test and during recovery. The mean discrepancy between methods varied in tests from -2.3 to 12.9 mmHg for systolic blood pressure level and from -4.3 to 18.2 mmHg for diastolic blood pressure level. Blood pressure responses to other tests were analysed using the value measured in the sitting position as the reference. The mean discrepancy between the methods in test responses varied from -6.3 to 8.9 mmHg for systolic responses and from -2.3 to 20.3 mmHg for diastolic responses. The data analysis indicates that the accuracy of the indirect method varies considerably between tests and also between subjects. We conclude that at present the standard cuff method cannot replace the direct method for determining blood pressure responses and reactivity.

Adult↗