The effects of amrinone versus dobutamine on myocardial mechanics and energetics after hypothermic global ischemia.

The effects on the postischemic myocardium of amrinone and dobutamine were studied in canine hearts that underwent 90 minutes of hypothermic (10 degrees C) arrested ischemia. In an isolated heart preparation cross-circulated by a support dog, left ventricular pressure-volume loops were collected under a constant afterload based on a mock circulatory system and a range of preload conditions controlled by a computerized servo volume pump. Dobutamine (0, 5, 10, 15 micrograms/kg per minute) and amrinone (0, 0.75, 1.5, 3.0 mg/kg) were tested in this order based on the weights of the support dogs in eight experiments. Changes in intrinsic myocardial contractility were analyzed as percent increases in the preload recruitable stroke work area from baselines. Dobutamine exhibited significant dose-related increases in the preload recruitable stroke work area. Amrinone did not produce significant increases in preload recruitable stroke work area at 0.75 mg/kg; amrinone's inotropic effect was equivalent to dobutamine, 5 micrograms/kg per minute at 1.5 mg/kg, and at the maximum dose (3.0 mg/kg) it was equivalent to dobutamine, 10 micrograms/kg per minute. The myocardial energetic efficiency was determined from the analysis of the myocardial oxygen consumption-pressure volume area relationship. The y intercept represents the basal metabolic oxygen requirement of the unloaded beating heart, and the slope is inversely proportional to the rate of energy conversion for increasing loading conditions. Dobutamine significantly increased the y intercepts, but it had no effects on the slopes. These changes demonstrate reduced myocardial efficiencies that are consistent with previous reports. Amrinone (0.75 and 1.50 mg/kg) did not result in change of the y intercepts and the slopes of myocardial oxygen consumption-pressure-volume area relationship from baseline conditions. The y intercept was increased with amrinone (3.0 mg/kg), although still not significantly higher than baseline and not to the extents of the dobutamine group. Dobutamine did not have any primary effect on coronary resistance, while amrinone significantly reduced coronary resistance in all loading conditions at 1.5 and 3.0 mg/kg. This study demonstrates that the inotropic effects of amrinone tested under this constant afterload preparation were lower than those of dobutamine. Amrinone has a superior profile of myocardial efficiency on the postischemic myocardium since it does not produce the oxygen-wasting effects of the traditional inotropic agents such as the beta agonists. This benefit, together with amrinone's coronary dilating effects, critically improves the supply/demand ratio that may be of importance in certain clinical situations.

Neutrophil leukotriene generation increases after cardiopulmonary bypass.

BACKGROUND: Leukotriene B4 has been shown to play a role in the systemic inflammatory response after cardiopulmonary bypass in experimental animal models; however, the importance of this mediator in human beings undergoing cardiac operations has not been established. METHODS: The neutrophils of ten patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were studied for their ability to generate leukotrienes at the time of the induction of anesthesia, the institution of cardiopulmonary bypass, the removal of the aortic crossclamp, at the end of the operation, on admission to the intensive care unit, and on postoperative days 1 and 2 RESULTS: After cardiopulmonary bypass, the generation of chemotactic leukotrienes rose significantly and remained elevated on the first postoperative day compared with prebypass values (prebypass 133.8 +/- 10.7 versus postbypass 192.7 +/- 19.2 [p < 0.05] and first postoperative day 196.6 +/- 13.8 [p < 0.05]). The increases in plasma complement and lactoferrin levels, although significant, were not sustained. In addition to the neutrophil count, the potential leukotriene and oxygen radical produced was significantly increased, and this increase was correlated with postoperative length of stay. CONCLUSION: These observations support the laboratory data documenting that the rise in leukotriene generation after cardiopulmonary bypass includes human patients.

Ischemic tolerance of the arrested heart during warm cardioplegia.

Normothermic blood cardioplegia has recently generated interest as an alternative method of myocardial protection during cardiopulmonary bypass (CPB) surgery. One disadvantage is the obligatory interruption of coronary flow during the distal coronary anastomosis. This study was designed to determine the safe normothermic ischemic time of the arrested and decompressed heart. Under normothermic CPB (37 degrees C), initial cardioplegic arrest was induced with 750 cc of warm (37 degrees C) hyperkalemic blood cardioplegia in 21 adult dogs. The heart then received warm blood cardioplegia either continuously (50 cc/min), every 5 min (250 cc each) or every 10 min (350 cc each) for a total equivalent ischemic time of 30 min (n = 7 in each group). Left ventricular pressure-volume (PV) loops were measured by micromanometer and conductance (volume) catheters before, at 60 and 90 min after aortic cross-clamping. Systolic function was measured as the preload recruitable stroke work area derived from the stroke work-end diastolic volume relationship, and the diastolic stiffness constant (k) was derived from the exponential diastolic PV relationship. The q5 min group sustained minor deterioration in diastolic function while its systolic function was well maintained during recovery. There were significant reductions in both the diastolic and systolic functions in the q10 min group. The maximum drops in the septal wall pH during aortic cross-clamping were 0.05 +/- 0.02 (not significant), 0.19 +/- 0.06 (P < 0.05), and 0.40 +/- 0.09 (P < 0.01) for the continuous, q5 min and q10 min groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The Internet as a source of information on breast augmentation.

The Internet was evaluated as a source of information for the layperson on the topic of breast augmentation. Three commonly used search engines (Excite, AOL, and Yahoo) were employed using the term "breast augmentation." These sites were then evaluated by each of three experienced plastic surgeons for their quality and content. Separately, 17 health Web sites were identified as authoritative by means of recommendation in lay publications. Each "supersite" was accessed, and its search engine was used. The top 10 hits for "breast augmentation" on each site were then evaluated by the senior author for content (Matthews). We found the majority of sites identified by the general search engines (AOL, Excite, Yahoo) to be physician Web sites. Forty-one unique sites were found that applied to the topic. Four of the "hits" did not actually apply to the topic. In general, the applicable Web sites contained limited but accurate procedural details and offered an interactive forum, most commonly email responses. Photographic documentation was given in less than half the sites reviewed, and most of the results shown were only "good" outcomes. Most sites did not discuss any complications of surgical procedures, but those that did were usually accurate. Eighty-three percent of the sites were biased toward a particular surgical technique. The reviewers believe that only about 15 percent of the sites were acceptable to recommend to their patients. The senior author accessed 17 Web sites that are considered authoritative health information Web sites. Each of these sites was searched for information on breast augmentation by means of its internal search engine. Only 29 percent (5 of 17) had any information in their top 10 hits. Three sites had only chat transcripts. One site had limited but accurate information with a link to the American Society of Plastic Surgeons, and one site had scientific information on product safety. No site met the criteria of accurate, complete information on the surgical procedure of breast augmentation. This study demonstrates that it is difficult for the average layperson to get authoritative information quickly and easily on at least one aspect of cosmetic surgery.

Preliminary study of health value as a moderator of the link between age and life satisfaction.

In the present study of the influence of health value as a potential moderator of age and life satisfaction. 157 undergraduate students (M = 20.8 yr.) completed a battery in which they provided demographic information and completed a number of different self report measures, including the Satisfaction With Life Scale and the Health Value Scale. A 2 (younger vs older) x 2 (high vs low health value) analysis of variance with life satisfaction as the dependent variable showed a significant man effect for health value and a significant interaction between age and health value but no man effect for age. These findings support health value as a moderator of the relation between age and psychological well-being. Implications for research and practice are discussed.

How the value of health moderates the link between age and depressive symptoms: further evidence.

To extend earlier findings, this pilot study explored the role of self-reported value of health as a moderator between age and scores on the Beck Depression Inventory. 157 undergraduate students completed the Health Value Scale and the Beck inventory. There was no significant main effect for age with scores on the Beck inventory; however, scores on the Health Value Scale and their interaction with age were significant contributors to scores on the Beck Depression Inventory. These results are consistent with earlier findings. Implications for research and development are discussed.

Plastic surgical considerations in lighting injuries.

Lightning injuries affect 1,000 to 1,500 people per year in the United States. While fatalities are uncommon, lightning frequently causes injuries within the treatment purview of the plastic surgeon. Recognition of common patterns of lightning injury, their prognosis, and treatments are important for the plastic surgeon. Lightning injury, although electrical, is very different from other more common electrical injuries. Burn injuries are seen, but are usually superficial and heal without surgery. Deep-tissue injury is rare. Neurovascular compromise of the extremities is common and may lead to plastic surgical consultation for intervention. Spontaneous recovery is the rule, however. Several patients are described who illustrate these injuries, and treatment guidelines are proposed.