Normovolaemic haemodilution and hyperoxia have no effect on fractal dimension of regional myocardial perfusion in dogs

Hypervolaemic haemodilution makes myocardial perfusion more homogenous as reflected by reduced fractal dimension of regional myocardial perfusion. The clinically more commonly performed acute normovolaemic haemodilution, however, has not yet been studied in this respect. Hyperoxic ventilation with 100% oxygen is used in conjunction with haemodilution to compensate for low oxygen content by increasing physically dissolved oxygen in plasma. Since hyperoxia is known to cause disturbance in microcirculatory regulation we studied the effects of acute normovolaemic haemodilution to haematocrit (hct) 20 ± 1% and hyperoxia on regional myocardial perfusion heterogeneity in 22 anaesthetized dogs using fractal and correlation analysis. Regional myocardial perfusion was assessed with radioactive microspheres. The results of the study were that heart rate, blood volume and arterial pressure were unchanged during haemodilution. Cardiac index was 3.6 ± 0.7 L min^?1 m^?2 before and 4.6 ± 0.7 L min^?1 m^?2 after haemodilution (P < 0.05). Fractal dimension (D) of regional myocardial perfusion was 1.17 ± 0.10 at baseline. Neither haemodilution (D = 1.19 ± 0.10) nor hyperoxia (D = 1.17 ± 0.10) altered fractal properties of regional myocardial perfusion. Spatial correlation of blood flow to adjacent tissue samples before haemodilution was 0.58 ± 0.15. Haemodilution and hyperoxia did not significantly influence spatial correlation (0.57 ± 0.12 vs. 0.60 ± 0.09; ns). We conclude that neither acute normovolaemic haemodilution nor haemodilution in combination with hyperoxic ventilation alter physiological myocardial perfusion heterogeneity.     

EFFECT OF INTERPLEURAL MORPHINE ON POSTOPERATIVE PAIN AND PULMONARY FUNCTION AFTER THORACOTOMY

We have investigated the effect of interpleural morphine onpostoperative pain and pulmonary function after thoracotomy.At the end of surgery, an interpleural catheter was insertedin 17 patients and, in a double-blind and randomized manner,either a bolus of morphine 2.5 mg interpleurally (i.p.) andnormal saline i.v. (group I) or, as a control for systemic absorption,morphine 2.5mg i.v. and i.p. saline (group II) was injected.After the initial bolus, a continuous infusion of morphine 0.5mg h^–1 i.p. and saline i.v. (group I) or morphine 0.5mg i.v. and saline i.p. (group II) was maintained for 24 h.Postoperative pain was assessed by a visual analogue scale,a numerical rating scale and the McGill Pain Questionnaire.Pulmonary function was assessed by spirometry. Supplementaryanalgesics, side effects, degree of sedation, vital signs andchest tube drainage were recorded. All variables were assessedon the day before surgery and 1, 2, 3, 4, 5, 6 and 24 h and7 days after surgery. Supplementary morphine was given uponrequest. There was no significant difference in any pain measureor postoperative pulmonary function variable between the groups.We conclude that, after thoracotomy. interpleural morphine doesnot provide superior analgesia or improve pulmonary functioncompared with systemic morphine.     

The costs of health damage and productivity losses attributable to cigarette smoking in Germany

Background: Smoking causes significant health damage and mayincur a significant economic burden to society. This study investigatesthe years of potential life lost, the direct medical costs andthe Indirect costs of cigarette smoking in Germany. Methods:Using the concept of attributable risks and the prevalence-basedapproach, smoking-attributable mortality and morbidity werecalculated for 1993. Neoplasms, cardiovascular diseases, respiratorydiseases, perinatal diseases and burn deaths were considered.Attributable risks stem from the literature and were processedin an epidemiological model. Costs were estimated from a societalperspective. Direct costs were mainly calculated based on routineutilization and expenditure statistics and indirect costs werecalculated according to the human capital approach. Results:Twenty-two percent of all male and 5% of all female deaths aswell as 1.5 million years of potential life lost were attributableto smoking. The costs of acute hospital care, in-patient rehabilitationcare, ambulatory care and prescribed drugs were 9.3 billionDEM, of mortality were 8.2 billion DEM and costs due to work-lossdays and early retirement were 16.4 billion DEM (discount rate3%). The total costs added up to 33.8 billion DEM, 415 DEM perinhabitant or 1,599 DEM per current smoker. Sensitivity analysesshowed that including the productivity loss of unpaid work leadsto a strong increase of indirect costs. Conclusions: This studyprovides a conservative estimate of the costs of smoking inGermany. The magnitude is considered sufficient reason to callfor stronger support of cost-effective, smoke-cessation measuresand of anti-smoking policy.     

Quantity-frequency measures of alcohol consumption: beverage-specific vs global questions

Estimates of alcohol consumption (ounces of absolute alcohol per day, AA) based on beverage-specific and global quantity-frequency (QF) questions were compared in a survey representative of the adult drinking population in New York State. Beverage-specific AA estimates were higher than global (0.72, 95% confidence intervals=0.68, 0.76) compared to 0.49 (95% confidence intervals=0.47, 0.51), although estimates were highly correlated (r=0.75). Discrepancies between beverage specific and global AA estimates increased as the number of beverages and the amount drunk increased. Sociodemographic characteristics were not significantly related to differences between beverage-specific and global AA estimates after adjusting for the amount drunk; however, drinking patterns did influence the differences. It was concluded that beverage-specific QF questions are probably more valid measures of alcohol consumption than global QF questions, but that the global questions provide useful information. Parallel analyses of variant global QF questions employed in the first US Health and Nutrition Examination Survey obtained similar results.     

Prostacyclin aerosol and inhaled nitric oxide fail to reverse pulmonary vasoconstriction induced by thromboxane analogue in dogs

Inhalation of either prostacyclin (PGI₂) as an aerosol or nitric oxide (NO) has been shown to elicit selective pulmonary vasodilation during hypoxic pulmonary vasoconstriction in dogs. Hypoxia may produce cardiovascular changes confounding interpretation of drug effects. Therefore, we investigated the effects of PGI₂-aerosol and inhaled NO (50 p.p.m.) on pulmonary pressure-flow relationships (P/Q_ plots) during thromboxane analogue (U46619) induced pulmonary vasoconstriction. In eight anaesthetized dogs infusion of U46619 (0.33 ± 0.18 μg kg_¹ min^-1) increased the slope (3.5 ± 1.1 to 8.4 ± 1.7 mmHg L^-1 min^-1, P < 0.001) and the intercept (4.4±2.3 to 10.2 ± 4.6 mmHg, P < 0.01) of P/Q plots indicating pulmonary vasoconstriction. Inhalation of both aerosolized PGI₂ solution (10μgmL^-1) and NO (50 p.p.m.) reduced neither the slope nor the intercept of the P/Q_ plots. Increasing the concentration of the aerosolized PGI₂ solution to 50 μg mL^-1: (n= 3) did not enhance the effect on pulmonary circulation but systemic vascular resistance fell by 23%. Oxygenation and intrapulmonary shunt remained unchanged during both PGI₂-aerosol and inhaled NO. The failure of PGI₂-aerosol to induce pulmonary vasodilation indicates that during aerosolization PGI₂-concentrations at receptor sites on pulmonary vessels were insufficient to surmount U46619 induced vasoconstriction; this notion is supported by unchanged arterial plasma concentrations of the PGI₂ degradation product 6-keto-PGF_lα. Considering that NO inhaled at comparable concentrations in sheep reversed U46619 induced pulmonary vasoconstriction, species differences may account for the failure of both PGI₂-aerosol and NO to dilate pulmonary vessels in dogs.