Clinical Assessment of Gestational Age

There is disagreement among authors as to what criteria are most reliable in assessing postnatal fetal age. A comparison–for objectivity, accuracy, and frequency of use– of specific criteria was made using three independent examiners at different educational levels: a second-year medical student, a perinatal nurse practitioner, and a pediatrics resident. It was shown that trained examiners develop favorite criteria which differ among examiners and thus sacrifice accuracy; however, accurate assessment of fetal age can be accomplished by an examiner with minimum clinical knowledge.     

Development of an improved multi-pressure-sensor probe for recording muscle contraction in human intestine

We have developed an improved semiconductor recording probe for monitoring motility of the upper small intestine in humans. The probe consists of six ultraminiature silicon pressure sensors spaced 10 cm apart and encased in a flexible polyurethane sheath. The probe is small [2.67 mm (8F) diameter], is easily passed transnasally, and is tolerated by patients for prolonged recording periods (24–36 hr) with a minimum of discomfort. The initial semiconductor and catheter material were those designed for use in the cardiovascular system, but they proved to be easily damaged by gastric acid and enzymes. After improvement of this probe, we now have recordings from more than 100 patients for an approximate total of 6000 hr of recording time. The improved probe is a durable recording device that facilitates the investigation of motility of the small intestine in humans in health and disease.This study was supported by funds from the Medical Research Service of the Veterans Administration and by National Institutes of Health Clinical Research Center grant RR-82.     

Evaluation of a solid-phase enzyme immunoassay for human choriogonadotropin beta subunit

We evaluated a quantitative solid-phase enzyme immunoassay for human choriogonadotropin beta subunit (beta-HCG) with anti-beta-HCG:horseradish peroxidase conjugate, recently marketed by Abbott Laboratories. We compared results on 56 patients' serum specimens, obtained mostly for followup of neoplastic disease, with those by a competitive radioimmunoassay kit. The correlation was good, the differences being of little clinical significance. Linear regression in the low and intermediate ranges gave a slope of 0.93, a y-intercept of 0.34, and a correlation coefficient of 0.97. Precision studies yielded an interassay CV of 6.4% in the intermediate range and 13% in the low range. Sensitivity was 0.69 int. unit/L. Cross reactivity was 1 to 2% with specimens fortified with lutropin or follitropin. The only substantial problem was with linearity in the upper part of the standard curve, especially in the interval, 100-200 int. units/L. This problem is obviated by adequate sample dilution.     

Assessment of patient management skills and clinical skills of practising doctors using computer-based case simulations and standardised patients

CONTEXT: Standardised assessments of practising doctors are receiving growing support, but theoretical and logistical issues pose serious obstacles. OBJECTIVES: To obtain reference performance levels from experienced doctors on computer-based case simulation (CCS) and standardised patient-based (SP) methods, and to evaluate the utility of these methods in diagnostic assessment. SETTING AND PARTICIPANTS: The study was carried out at a military tertiary care facility and involved 54 residents and credentialed staff from the emergency medicine, general surgery and internal medicine departments. MAIN OUTCOME MEASURES: Doctors completed 8 CCS and 8 SP cases targeted at doctors entering the profession. Standardised patient performances were compared to archived Year 4 medical student data. RESULTS: While staff doctors and residents performed well on both CCS and SP cases, a wide range of scores was exhibited on all cases. There were no significant differences between the scores of participants from differing specialties or of varying experience. Among participants who completed both CCS and SP testing (n = 44), a moderate positive correlation between CCS and SP checklist scores was observed. There was a negative correlation between doctor experience and SP checklist scores. Whereas the time students spent with SPs varied little with clinical task, doctors appeared to spend more time on communication/counselling cases than on cases involving acute/chronic medical problems. CONCLUSION: Computer-based case simulations and standardised patient-based assessments may be useful as part of a multimodal programme to evaluate practising doctors. Additional study is needed on SP standard setting and scoring methods. Establishing empirical likelihoods for a range of performances on assessments of this character should receive priority.     

Structure and function evaluation (SAFE): II. Comparison of optic disk and visual field characteristics

PURPOSE: To evaluate the relationship between glaucomatous structural damage to the optic nerve and development of visual field loss with standard automated perimetry (SAP) and short wavelength automated perimetry (SWAP). DESIGN: Cohort study. METHODS: Patients with elevated intraocular pressure and normal SAP visual fields were enrolled in this prospective study. Stereo optic disk photographs, SAP, and SWAP visual fields were obtained annually over a period of 4 or more years. Trained readers evaluated baseline and follow-up optic disk photographs for evidence of glaucomatous damage. Standard automated perimetry and SWAP examinations were evaluated according to previously validated criteria for development of confirmed visual field changes. RESULTS: Two-hundred ninety-five subjects (479 eyes) were enrolled. Following masked assessment of stereo photographs by an optic disk reading center, 272 of the 479 eyes were judged to have glaucomatous optic neuropathy at the time of study entry. Depending on the criteria employed, approximately 10% to 17.5% of all eyes developed confirmed visual field loss for SAP (conversions). Of the conversions, 75% to 80% had baseline glaucomatous optic disk damage, whereas normal and glaucomatous optic disks were equally divided (50%) among the nonconversion eyes. This difference was statistically significant (P <.003). Depending on the criteria employed, 4% to 12% of the eyes had confirmed SWAP deficits at baseline, and 4% to 8% developed confirmed SWAP defects at a follow-up examination. There was a greater percentage of eyes with a glaucomatous optic neuropathy in the group with SWAP deficits (75%-100%) than for those eyes in which SWAP remained normal (45%-60%). Some of these differences were statistically significant (P <.05). CONCLUSIONS: A strong relationship exists between glaucomatous optic disk damage at study entry and the subsequent development of a confirmed glaucomatous SAP visual field defect. A higher percentage of glaucomatous optic disks were also found in patients with SWAP deficits at baseline and in those who later developed SWAP deficits. These findings support the premise that a glaucomatous optic disk is predictive of the subsequent development of glaucomatous visual field loss.     

Corneal thickness as a risk factor for visual field loss in patients with preperimetric glaucomatous optic neuropathy

PURPOSE: To determine whether central corneal thickness (CCT) is a risk factor for visual field loss development among patients diagnosed with preperimetric glaucomatous optic neuropathy (GON). DESIGN: Observational cohort study. METHODS: The study included 98 eyes of 98 patients with GON, with a mean follow-up time of 4.3 +/- 2.7 years. Diagnosis of GON was based on masked assessment of optic disk stereophotographs. All patients had normal standard automated perimetry visual fields at baseline. Criteria for visual field abnormality were derived from a prior study. Several clinical factors (CCT, intraocular pressure, vertical cup-to-disk ratio, refraction, age, gender, family history of glaucoma, high blood pressure, cardiovascular disease, and migraine) were investigated to ascertain whether there is an association with development of repeatable visual field loss. Cox proportional hazards models were used to obtain hazard ratios (HR) and identify factors that predicted which individuals developed glaucomatous visual field loss during the follow-up period. RESULTS: Thirty-four patients (35%) developed repeatable visual field abnormality during follow-up. In multivariate analysis, risk factors that predicted the development of visual field loss were a thinner CCT (adjusted HR = 1.62/40 microm thinner; P =.023; 95% confidence interval [CI]: 1.07-2.45), higher baseline intraocular pressure (adjusted HR = 1.07/mm Hg; P =.022; 95% CI: 1.01-1.14), and larger baseline vertical cup-to-disk ratio (adjusted HR = 1.63/0.1 larger; P =.009; 95% CI: 1.13-2.35). The mean +/- standard deviation CCT of GON patients who developed visual field loss was 543 +/- 36 microm compared with 565 +/- 35 microm of those who did not develop visual field abnormalities (P =.005, Student t test). CONCLUSIONS: Central corneal thickness is a risk factor for development of visual field loss among patients diagnosed with preperimetric GON. It is important to consider CCT when establishing target intraocular pressure of patients with GON.