The application of basic science concepts to clinical problem-solving

This study looks at the relationship between anatomical concepts held by medical students and their clinical application, and develops a testable model of how students use basic science concepts for clinical problem-solving. According to the model, the essential prerequisites to solve a clinical problem using basic science information include the appropriate basic science knowledge, the ability to collect and interpret clinical information, with the key concept being the link that must then be made between clinical data and basic science. A detailed analysis of the individual components of the model should help to clarify and resolve some of the debate about the nature and balance of basic science and clinical education. A neurological diagnostic problem was used to test the assumptions of the model in a group of medical students who had minimal clinical experiences. There was no demonstrable relationship between anatomical knowledge as assessed by conventional tests and the diagnosis. There was a powerful relationship between measures of organization of knowledge and diagnosis, suggesting that the organization and development of concepts is the key to correct diagnosis. The findings have significant implications for assessment purposes and suggest that standard methods as generally practised may not measure the appropriate conceptual development and are not congruent with curricular objectives. Through the examination of its different learning outcome measures, the model may also be used to provide a profile of individual students or classes, which should help teachers and students deal with difficulties that may be experienced in learning to link clinical and basic science concepts.     

Comparison of three preverbal scales for postoperative pain assessment in a diverse pediatric sample

The purposes of this study were to compare the reliability and validity of three pain measurement scales for assessing pain in preverbal and nonverbal children and to determine which of the scales was mos tappropriate in a clinical setting to evaluate pain for infants and young children regardless of developmental stage or cognitive or physical disability. Pain scales tested were revised versions of the Riley Infant Pain Scale (RIPS), the Nursing Assessment of Pain Intensity (NAPI), and the Postoperative Pain Score (POPS). Purposive sampling of 391 postoperative infants and children was used for evaluation of pain in a midwestern children's hospital. Four assessments with each scale were done 1 hr apart by trained observers blinded to pain medications. Data analyses supported high inter-rater reliability, satisfactory discrimination between pain and no-pain observations, and suggested acceptability for all three scales with lower caregiver burden for RIPS and NAPI.     

Potentially Life-Threatening Cardiac Dysrhythmia in a Child with Selenium Deficiency and Phenylketonuria

ABSTRACT. Selenium deficiency is a frequent finding in children with phenylketonuria (PKU) receiving dietary treatment. We report the occurrence of episodic ventricular tachycardia in a 9-month-old infant with PKU. Serum selenium (Se), 0.13 μmol/1 (normal range 0.28–1.12 μmol/1, mean ± 2 SD), and whole blood glutathione peroxidase (GSHPX), 16 U/g Hb (normal range 19.5–34.3 U/g Hb, mean ± 2 SD), were low. Auscultation of cardiac rhythm is recommended during the routine follow-up of young children with PKU. Se deficiency should be considered in the aetiology of a dysrhythmia and corrected with Se supplementation.     

Stroke Volume and the Three Phase Cardiac Output Rate Relationship with Ventricular Pacing

Knowledge of how stroke volume (SV), and hence cardiac output (CO), changes with ventricular pacing rate (R) constitutes a key aspect of sensor driven, variable rate pacemakers. It has been established that the relationship between CO and pacing rate exhibits three phases for rest and constant exercise. At low rates (phase 1), CO increases with increasing R; with additional rate increase (phase 2), CO either remains constant or increases slightly; and above some critical rate, CO decreases (phase 3). However, the nature of the relationship between SV and pacing rate has not been as clearly described. Therefore, the objectives of this study were (1) to describe and document the relationship between SV and R, and (2) to demonstrate the consequence of this relationship in terms of the three phase CO versus R relationship. In six anesthetized dogs, right ventricular SV was determined from pulmonary artery blood flow measured using an electromagnetic flow meter, and the right ventricle was paced over a range of rates. In general, SV decreased with increasing R, although the exact nature of the relationship varied from animal to animal. The results demonstrate that it is the manner in which SV decreases with increasing R that determines the three phase relationship between CO and R. The relationships described in this study have important implications for choosing pacing rates for patients receiving sensor driven, variable rate pacemakers.     

EFFECTS OF SOMATOSTATIN ANALOGUE SMS 201–995 IN NORMAL MAN

Long-acting somatostatin analogues may be of benefit in certain hypersecretory endocrine and gastrointestinal disorders. The 24 h hormonal and metabolic profiles of six normal male subjects receiving a twice daily subcutaneous injection of one such analogue SMS 201-995, 50 micrograms, has been compared to that obtained following placebo injection. Spontaneous daytime peaks of GH secretion were delayed until 1400 h following SMS 201-995 but nocturnal and total 24 h GH secretion were unaffected. The nocturnal rise in thyrotrophin was abolished by SMS 201-995 but thyroid function was unaffected. Insulin levels were suppressed following SMS 201-995 and the response to meals was inhibited. Glucose intolerance followed main meals. Glucagon levels were suppressed for up to 6 h. Circulating alanine levels were raised between 1200 h and 0600 h and there were intermittent elevations in lactate, pyruvate, glycerol and 3-hydroxybutyrate. Amino acid levels, including branched chain amino acids, were also increased. All six subjects suffered gastrointestinal side-effects. SMS 201-995, 50 micrograms, given twice daily shortly before meals does not suppress 24 h GH secretion, but demonstrates significant effects on metabolism and causes side effects in normal subjects.