Comparison of gastric mucosal pH and clinical judgement in critically ill patients

OBJECTIVES: To compare gastric tonometry (pHi) with estimates of pHi in ill injured patients, and to correlate pHi with haemodynamic variables. DESIGN: Prospective, non-interventional study. SETTING: ICU of Level I trauma centre, USA. MAIN OUTCOME MEASURES: 154 gastric tonometry measurements were compared with physicians' estimates of adequacy of resuscitation. Resuscitation was categorised as inadequate (pHi < 7.35) or adequate (pHi> or = 7.35). Measured and estimated pHi were also compared with oxygen delivery, oxygen consumption, cardiac index, mixed venous O2 saturation, and critical illness scores. RESULTS: Estimated pHi was often higher than measured pHi in the judgement of all four surgical intensive care physicians. Measured pHi correlated positively with mixed venous O2 tension (r = 0.21). There were significant negative correlations between measured pHi and both oxygen delivery (r = -0.25) and oxygen consumption (r = 0.28). Estimated pHi correlated positively with mean arterial pressure (r = 0.21) and hospital day (r = 0.26); it correlated negatively with pulmonary arterial elastance (r = -0.35). CONCLUSION: Experienced intensive care physicians tended to overestimate visceral perfusion, which suggests that gastric tonometry adds useful information over and above routine haemodynamic indices. Arterial blood pressure and mixed venous oxygen saturation correlated better with measured pHi than with other indices of perfusion.     

Photography in bite mark and patterned injury documentation--Part 1

A case involving multiple bite marks is presented. The bite marks were photographed over a 31-day period to document the injuries and preserve their evidentiary value. The evidence recovered at each photography session is discussed and photographs are presented for review. Suggestions concerning the need for more research are presented.     

Effectiveness of chlorine dioxide in disinfection on two soft denture liners

OBJECTIVE: The purpose of this study was to evaluate a hydroxylapatite-based material and calcium sulfate when each was used under a resin-modified glass ionomer cement to repair furcation perforations. STUDY DESIGN: Perforations of pulp chamber floors were made in 72 teeth of 9 dogs. Perforations were divided into 3 equal-sized groups and repaired with resin-modified glass ionomer either alone or over an artificial floor. The artificial floor was either a hydroxylapatite-based material or calcium sulfate. Three dogs were killed at each of 3 intervals (1, 3, and 6 months). The tissue response to the tested materials was evaluated clinically, radiographically, and histologically. RESULTS: The hydroxylapatite-based material showed the highest radiographic success; this was followed by calcium sulfate and glass ionomer. From histologic evaluation, the average success rate was found to be 67% for calcium sulfate, 62% for the hydroxylapatite-based material, and 59% for glass ionomer. However, there was no statistical significant difference with the resin-modified glass ionomer when it was used alone and when it was used over a barrier. There was also no significant difference between the hydroxylapatite-based material and the calcium sulfate when they were used as artificial floors. CONCLUSION: The use of an artificial floor may not be necessary when flowable resin-modified glass ionomer cements are used.     

Use of cardiopulmonary bypass to salvage patients with multiple-chamber heart wounds

BACKGROUND: The need for cardiopulmonary bypass in the treatment of penetrating heart injuries is debated. OBJECTIVES: To review our experience with penetrating heart injuries and determine the indications and outcome for cardiopulmonary bypass. DESIGN: Retrospective review. SETTING: A university-based, level I trauma center. PATIENTS: All victims of penetrating heart injury presenting between July 1, 1989, and December 31, 1995. METHODS: Medical records were reviewed for demographic and physiological data, operative findings, and outcome. RESULTS: Overall survival for 106 patients with penetrating heart injury was 55%. In an effort to resuscitate the heart, 4 patients with unresponsive cardiogenic shock were placed on cardiopulmonary bypass; none survived. Of 30 patients with multiple-chamber injuries, 11 presented with signs of life and 7 survived. Cardiopulmonary bypass was essential to repair complex injuries in 2 of the 7 survivors. CONCLUSION: Cardiopulmonary bypass was ineffective in salvaging patients with cardiogenic shock but was essential in some patients with complex multiple-chamber cardiac injuries that could not be exposed and repaired by other means.     

Hemodynamic tolerance of intravascular contrast agents for magnetic resonance imaging

RATIONALE AND OBJECTIVES: Intravascular contrast agents for magnetic resonance imaging (MRI) facilitate the quantification of tissue perfusion. The authors determined the hemodynamic tolerance of these agents. METHODS: Doses of 0.05, 0.15, and 0.45 mmol/kg of the polymeric intravascular contrast agent gadolinium-DTPA-polylysine, and di-nitrobenzyl-gadolinium-DTPA, a non-polymeric intravascular contrast agent with high protein binding, and gadolinium-DTPA dimeglumine, a paramagnetic contrast agent with extracellular distribution, were injected into 18 normal male rats as a peripheral intravenous bolus. Systolic, diastolic, and mean blood pressure, left ventricular end-diastolic and developed pressure, positive rate of pressure change (+dP/dt), dP/dt, the rate-pressure product, and heart rate were recorded during a period of 20 minutes. Hemodynamic effects were established by analysis of variance for repeated measurements. RESULTS: There was a transient increase of all blood pressure parameters and contractility for Gd-DTPA-polylysine at the dose of 0.45 mmol/kg only. Di-nitrobenzyl-Gd-DTPA increased blood pressure parameters at 0.45 mmol/kg only. At doses of 0.05 and 0.15 mmol/kg, no significant hemodynamic effects were observed. CONCLUSIONS: The authors conclude that Gd-DTPA-polylysine is hemodynamically safe at doses to 0.15 mmol/kg and acts like a plasma expander at higher doses after peripheral bolus injection in normal rats. Additional investigations are indicated to elucidate the mechanism of a nonsignificant and satiable transient hemodynamic depression after injection of 0.05 mmol/kg DNB-Gd-DTPA.     

Absorption and elimination kinetics of zidovudine in the cerebrospinal fluid in HIV-1-infected patients

The first two surveys of the dental health of young Finnish men were conducted in 1919 and 1965. The objective of four subsequent surveys (1976, 1981, 1986, and 1991) was to collect both interview and clinical examination data for the monitoring of changes in the oral health status of the recruits. A significant reduction in self-reported toothache, gingival bleeding, and number of decayed teeth was observed from 1976 to 1991. At examination, the numbers of decayed teeth, teeth indicated for extraction, teeth in need of fillings, and missing teeth decreased substantially, as did the teeth with visible plaque, subgingival calculus, and teeth with 4-mm or deeper periodontal pockets. This comprehensive series of successive cross-sectional oral health surveys clearly shows that since 1976 a significant decrease in oral disease and treatment needs has taken place among the Finnish population of young men.     

Repeatability and reproducibility estimates from collaborative studies based on total concentration of trace analytes

In the process of validating a given analytical method for the total concentration of a trace analyte, the precision indicators, repeatability and reproducibility, are obtained from a collaborative study of the method based on a standard one-way completely randomized model. This report discusses the shortcomings of the statistical models used in such studies, defines the component makeup for estimates of the repeatability and reproducibility variances based on these models, and considers suggestions offered as new policy regarding method performance based on total concentration.     

The role of glycoproteins in neural development function, and disease

Glycoproteins play key roles in the development, structuring, and subsequent functioning of the nervous system. However, the complex glycosylation process is a critical component in the biosynthesis of CNS glycoproteins that may be susceptible to the actions of toxicological agents or may be altered by genetic defects. This review will provide an outline of the complexity of this glycosylation process and of some of the key neural glycoproteins that play particular roles in neural development and in synaptic plasticity in the mature CNS. Finally, the potential of glycoproteins as targets for CNS disorders will be discussed.     

Regulation of beta-adrenoceptors in the guinea-pig sinoatrial node

This study examined the changes of beta-adrenoceptors in the guinea-pig sinoatrial nodal region following 7 day (-)-isoprenaline (400 micrograms/kg/h s.c.) infusion and the relationship between beta-adrenoceptor desensitization and receptor down-regulation. Changes in beta 1- and beta 2-adrenoceptor density were measured using quantitative autoradiography and function in organ bath studies. (-)-Isoprenaline treatment produced a marked decrease in total (from 57.5 to 33.9 fmol/mg protein), beta 1- (from 49.4 to 32.8 fmol/mg protein), and beta 2-adrenoceptor density (from 8.1 to 1.05 fmol/mg protein) in the sinoatrial node. In adjacent right atrium, treatment produced no change in total (39.5 and 36.7 fmol/mg protein) or beta 1-adrenoceptors (35.9 and 36.4 fmol/mg protein) but did decrease beta 2-adrenoceptors (from 3.7 to 0.3 fmol/mg protein). Chronotropic effects were measured in spontaneously beating right atrium. Procaterol, a selective beta 2-adrenoceptor agonist, caused a biphasic chronotropic response in control right atria, the first part of which was abolished in the tissue from treated animals. The maximum increase in right atrial rate to RO363, a beta 1-adrenoceptor selective partial agonist, was reduced from 114 bpm in control to 43 bpm in treated animals. In electrically driven right atrium with the sinoatrial node removed procaterol failed to produce a positive inotropic response via beta 2-adrenoceptors, but the maximum response to RO363 was reduced from 0.75 g in the control tissue to 0.12 g in the treated tissue. This study showed that changes in beta 2-adrenoceptor density following 7 day (-)-isoprenaline infusion are compatible with reduced functional responsiveness in the SA node. The reduction of beta 1-adrenoceptor number in the SA node was also compatible with the reduced chronotropic response in this tissue. However the lack of effect on beta 1-adrenoceptor density in the right atrium was not consistent with the decrease in beta 1-adrenoceptor mediated inotropic response in this tissue. This suggests that beta-adrenoceptor desensitization is not always associated with receptor down-regulation but depends also on the changes in the cell signalling system beyond the level of the receptor which differ according to the cardiac location.     

The effect of an infusion of low molecular weight dextran on peripheral resistance in patients with arteriosclerosis

Low molecular weight dextran is frequently given to improve the flow of blood to the periphery, but its mode of action is uncertain. We measured the effect of an infusion of 500 ml of Dextran 40 on the peripheral resistance in 12 patients undergoing reconstructive surgery for atherosclerotic occlusion of the superficial femoral artery. After the infusion, values of packed cell volume and blood viscosity indicated haemodilution. There was a consistent increase in mean flow and a fall in peripheral resistance. There was no correlation between change in viscosity and change in peripheral resistance, but there was a good correlation between the percentage change in resistance and the initial resistance. This suggests that the increase in flow of blood was due to reflex vasodilatation rather than to any reduction in viscosity.