Selective laser trabeculoplasty in phakic and pseudophakic eyes.

BACKGROUND AND OBJECTIVE: To evaluate the effect of pseudophakia on the success of selective laser trabeculoplasty in lowering intraocular pressure (IOP). PATIENTS AND METHODS: In this retrospective, nonrandomized clinical trial, a chart review of all patients who underwent selective laser trabeculoplasty from September 2002 to June 2004 using a frequency-doubled Q-switched 532-nm Nd:YAG laser was performed. Changes in IOP and statistical significance were determined at each follow-up period. Average decrease in IOP and success rates for phakic and pseudophakic eyes were compared statistically at each time period. RESULTS: In the phakic group, mean IOP decreased from 18.1 to 15.5 mm Hg (P < .0005) and mean glaucoma medication use decreased from 2.1 to 1.6 medications after 24 months of follow-up. In the pseudophakic group, mean IOP decreased from 18.3 to 15.2 mm Hg (P < .005) and mean glaucoma medication use decreased from 2.2 to 1.6 medications. Success rates ranged from 54% to 67% in the phakic group and 52% to 65% in the pseudophakic group. No statistically significant difference between phakic and pseudophakic eyes in decreased IOP or success rates was seen at any time point (P > .05). No significant complications occurred in either group. CONCLUSIONS: Selective laser trabeculoplasty is effective in lowering IOP in both phakic and pseudophakic patients.     

Persistent effects on blood pressure and renal haemodynamics following chronic angiotensin converting enzyme inhibition with perindopril

Spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats aged 4 and 16 weeks were given an acute oral dose of either Perindopril (3 mg/kg) or vehicle. Direct blood pressure (BP), glomerular filtration rate (GFR) and renal blood flow (RBF) were measured, and renal vascular resistance (RVR) calculated. GFR and RBF were lower in vehicle-treated SHR than WKY at 4 weeks of age, but were not different at 16 weeks. Acute Perindopril increased GFR and RBF and reduced RVR in both strains at both 4 and 16 weeks. Total body sodium, sodium intake and blood pressure were measured in SHR and WKY from 1 to 28 weeks of age. Rats of both strains were treated daily between 4 and 16 weeks of age with either Perindopril (3 mg/kg per day) or vehicle. Chronic Perindopril treatment prevented the development of hypertension in the SHR. From 16 to 28 weeks of age, after stopping Perindopril, BP rose slowly in SHR, but remained lower than vehicle-treated SHR. No changes in total body sodium occurred during Perindopril treatment. GFR and RBF were measured in SHR and WKY chronically treated with either Perindopril or vehicle, 3 days or 12 weeks after stopping treatment. In WKY, GFR and RBF were not different between Perindopril-treated and untreated rats at either measurement. In SHR, GFR and RBF remained significantly higher in rats previously treated with Perindopril at both ages. These findings suggest that renal haemodynamic abnormalities may be important in the initiation of hypertension in the SHR. These renal circulatory abnormalities and the hypertension of the SHR depend, at least in part, on intact converting enzyme activity, yet appear to be independent of abnormalities of total body sodium. At a later age, hypertension seems to develop independently of renal vascular abnormalities.     

Ketamine induction and monoamine oxidase inhibitors

A 42-year-old woman taking tranylcypromine, a monoamine oxidase (MAO) inhibitor, was hypovolemic from a ruptured ectopic pregnancy and required an emergency laparotomy. Anesthetic induction with ketamine, an agent with sympathomimetic properties, was used because of her hypovolemia, despite theoretical concerns of precipitating an adrenergic crisis. The patient's hemodynamic course remained unchanged with induction and intubation, and with further fluid and blood administration, satisfactory hemodynamic conditions were obtained. This report is believed to be the first to describe the use of ketamine in a patient taking MAO inhibitors.     

A mechanical study of six digital pulley reconstruction techniques: Part I. Mechanical effectiveness

A laboratory study on fresh-frozen human cadaver limbs compared six types of flexor tendon pulley reconstruction in the fingers. The reconstructions used were those described by (1) Bunnell, (2) Karev, (3) Weilby, and (4) Lister, and two types developed by us that have not been previously described. The pulleys were studied in specific configurations to determine their effectiveness in transforming tendon excursion into finger flexion. In each finger, comparison was made between the amount of tendon excursion required for full flexion with an intact pulley system versus the various types of reconstructed pulleys. The ratio of these two values was defined as the mechanical effectiveness of the pulley reconstruction. The Karve reconstruction was most effective at 108.2%, which was significantly different from the other five reconstructions (p less than 0.01). The remaining reconstructions ranged in effectiveness from 80.0% to 88.5%.     

Endotracheal suctioning causes right upper lobe collapse in intubated children

Objective: Right upper lobe collapse is a common radiographic finding in intubated children. We hypothesized that deep suctioning and uncontrolled negative pressures during endotracheal tube suctioning were significant contributory factors. Methods : The incidence of right upper lobe (RUL) collapse in intubated, ventilated children on a paediatric cardiac intensive care unit was determined over a 3-month period ( n = 102). Graduated suction catheters and suction vacuums of < 165 cm H₂O were then introduced. Another prospective audit was carried out 3 months later ( n = 60). Results : We found that 24% developed RUL collapse and 4 developed an apical pneumothorax. Following the introduction of graduated catheters and controlled vacuums pressures, a significant reduction in the incidence of RUL collapse, to 7%, was observed ( p < 0.05). Conclusions : We conclude that high negative pressure and deep-suctioning causes RUL collapse in children. Any lobar collapse not only prolongs the child's stay in intensive care, but can be associated with further morbidity which may have a serious implication. By improving suctioning technique this morbidity can be significantly reduced.     

Comparison of Track XI fluorometric immunoassay with Bio-EnzaBead enzyme-linked immunosorbent assay for detection of serum antibody to mouse hepatitis virus.

The Track XI system (Microbiological Associates, Bethesda, Md.) was compared with the Bio-EnzaBead assay (Organon Teknika, Durham, N.C.) for the detection of antibody to mouse hepatitis virus (MHV). Strain A/J mice were inoculated intranasally with MHV type 3. Sera were collected at 1, 2, 4, and 9 weeks postinoculation and tested. Individual serum samples were retested twice by each method. The results suggested that the Track XI system was more sensitive and reliable than the Bio-EnzaBead assay in detecting antibody to MHV type 3 in individual serum samples from A/J mice.     

Modeling a medical environment: an ontology for integrated medical informatics design

Modern medical environments have seen an increase in technological complexity and pressures of handling more patients with fewer resources, resulting in higher demands on medical practitioners. Medical informatics designers will have to focus on the problem of organizing medical information more effectively to enable practitioners to cope with these challenges. This article addresses this research problem for the particular area of medical problem solving in patient care. First, we describe a traditional modeling approach for medical reasoning used as a basis for developing some decision support systems. We argue these models may be faithful to what is known about biomedical knowledge, but they have limitations for human problem solving, especially in unanticipated situations. Second, we present an ontological framework, known as the abstraction hierarchy (Rasmussen, IEEE Trans. Man. Cybernetics 15 (1985) 234-243), for integrating patient representations that are faithful to existing biomedical knowledge and that are consistent with what is known about human problem solving. Through an example of a critical event in the operating room, we reveal how this framework can support medical problem solving in unanticipated situations. Third, we show how to use these representations as a frame of reference for mapping medical roles, responsibilities, sensors, and controls in an operating room context. Finally, we provide some insight for medical informatics designers in using this framework to design novel training programs and human-computer displays.