How to do safe sternal reentry and the risk factors of redo cardiac surgery: A 21-year review with zero major cardiac injury

Objectives: Resternotomy is a common part of cardiac surgical practice. Associated with resternotomy are the risks of cardiac injury and catastrophic hemorrhage and the subsequent elevated morbidity and mortality in the operating room or during the postoperative period. The technique of direct vision resternotomy is safe and has fewer, if any, serious cardiac injuries. The technique, the reduced need for groin cannulation and the overall low operative mortality and morbidity are the focus of this restrospective analysis. Methods: The records of 495 patients undergoing 546 resternotomies over a 21-year period to January 2000 were reviewed. All consecutive reoperations by the one surgeon comprised patients over the age of 20 at first resternotomy: M:F 343:203, mean age 57 years (range 20 to 85, median age 60). The mean NYHA grade was 2.3 [with 67 patients (1), 273 (11),159 (111), 43 (IV), and 4 (V classification)] with elective reoperation in 94.6%. Cardiac injury was graded into five groups and the incidence and reasons for groin cannulation estimated. The morbidity and mortality as a result of the reoperation and resternotomy were assessed. Results: The hospital/30 day mortality was 2.9% (95% Cl: 1.6%-4.4%) (16 deaths) over the 21 years. First (481), second (53), and third (12) resternotomies produced 307 uncomplicated technical reopenings, 203 slower but uncomplicated procedures, 9 minor superficial cardiac lacerations, and no moderate or severe cardiac injuries. Direct vision resternotomy is crystalized into the principle that only adhesions that are visualized from below are divided and only sternal bone that is freed of adhesions is sewn. Groin exposure was never performed prophylactically for resternotomy. Fourteen patients (2.6%) had such cannulation for aortic dissection/aneurysm (9 patients), excessive sternal adherence of cardiac structures (3 patients), presurgery cardiac arrest (1 patient), and high aortic cannulation desired and not possible (1 patient). The average postop blood loss was 594 mL (95% CI:558-631) in the first 12 hours. The need to return to the operating room for control of excessive bleeding was 2% (11 patients). Blood transfusion was given in 65% of the resternotomy procedures over the 21 years (mean 854 mL 95% Cl 765-945 mL) and 41% over the last 5 years. Conclusions: The technique of direct vision resternotomy has been associated with zero moderate or major cardiac injury/catastrophic hemorrhage at reoperation. Few patients have required groin cannulation. In the postoperative period, there was acceptable blood loss, transfusion rates, reduced morbidity, and moderate low mortality for this potentially high risk group.

Seedling responses of four Australian tree species to toxic concentrations of manganese in solution culture

Little is known about the responses of Australian plants to excess metal, including Mn. It is important to remedy this lack of information so that knowledgeable decisions can be made about managing Mn contaminated sites where inhabited by Australian vegetation. Acacia holosericea, Melaleuca leucadendra, Eucalyptus crebra and Eucalyptus camaldulensis were grown in dilute solution culture for 10 weeks. The seedlings ( 42 days old) were exposed to six Mn treatments viz., 1, 8, 32, 128, 512 and 2048 muM. The order of tolerance to toxic concentrations of Mn was A. holosericea congruent to = E. crebra < M. leucadendra < E. camaldulensis, the critical external concentrations being approximately 5.1, 5.0, 21 and 330 muM, respectively. The critical tissue Mn concentrations for the youngest fully expanded leaf and total shoots were, respectively, 265 and 215 mug g(-1) DM for A. holosericea, 445 and 495 mug g(-1) DM for M. leucadendra, 495 and 710 mug g(-1) DM for E. crebra and 7230 and 6510 mug g(-1) DM for E. camaldulensis. The high tolerance of E. camaldulensis ( as opposed to the sensitivity of E. crebra) to excess Mn raises concern about fauna feeding on the plant and is consistent with hypotheses suggesting the Eucalyptus subgenus Symphomyrtus is particularly tolerant of stress, including excess Mn. The results from this paper provide the first comprehensive combination of growth responses, critical external concentrations, critical tissue concentrations and plant toxicity symptoms for three important Australian genera, viz., Eucalyptus, Acacia and Melaleuca, for use in the management of Mn toxic sites.

The influence of genetic and environmental factors in estimations of current body size, desired body size, and body dissatisfaction

The objective was to investigate the genetic epidemiology of figural stimuli. Standard figural stimuli were available from 5,325 complete twin pairs: 1,751 (32.9%) were monozygotic females, 1,068 (20.1%) were dizygotic females, 752 (14.1%) were monozygotic males, 495 (9.3%) were dizygotic males, and 1,259 (23.6%) were dizygotic male-female pairs. Univariate twin analyses were used to examine the influences on the individual variation in current body size and ideal body size. These data were analysed separately for men and women in each of five age groups. A factorial analysis of variance, with polychoric correlations between twin pairs as the dependent variable, and age, sex, zygosity, and the three interaction terms (age x sex, age x zygosity, sex x zygosity) as independent variables, was used to examine trends across the whole data set. Results showed genetic influences had the largest impact on the individual variation in current body size measures, whereas non-shared environmental influences were associated with the majority of individual variation in ideal body size. There was a significant main effect of zygosity (heritability) in predicting polychoric correlations for current body size and body dissatisfaction. There was a significant main effect of gender and zygosity in predicting ideal body size, with a gender x zygosity interaction. In common with BMI, heritability is important in influencing the estimation of current body size. Selection of desired body size for both men and women is more strongly influenced by environmental factors.

Physiological and symptomatic responses to cycling and walking in intermittent claudication

To shed light on the potential efficacy of cycling as a resting modality in the treatment of intermittent claudication (IC), this study compared physiological and symptomatic responses to graded walking and cycling tests in claudicants. Sixteen subjects with peripheral arterial disease (resting ankle:brachial index (ABI) < 0.9) and IC completed a maximal graded treadmill walking (T) and cycle (C) Lest after three familiarization tests on each mode. During cacti test, symptoms, oxygen uptake (VO2), minute ventilation (V-E), (respiratory exchange ratio) (RER) and heart rate (HR) were measured, and for 10 min after each Lest the brachial and ankle systolic pressures were recorded, All but One subject experienced calf pain as the primary limiting symptom during T whereas the symptoms were more varied during C and included thigh pain, calf pain and dyspnoea, Although maximal exercise time was significantly longer on C than T (690 +/- 67 vs, 495 +/- 57 s), peak VO2, peak, V-E and peak heart rate during C and T were not different; whereas peak RER was higher during C. These responses during C and T were also positively 1, (P < 0.05) with each other, with the exception of RER. The postexercise systolic pressures were also not different between C and T. However, the peak decline ill ankle pressures from resting values after C and T were not correlated with each other. Thew data demonstrate that cycling and walking induce a similar level of metabolic and cardiovascular strain, but that the primary limiting symptoms and haemodynamic response in an individual's extremity, measured after exercise, can differ substantially between these two modes.