Quantitative evaluation of hand cranking a roller pump in a crisis management drill

The heart-lung machines for open-heart surgery have improved over the past 50 years; they rarely break down and are almost always equipped with backup batteries. The hand-cranking procedure only becomes necessary when a pump breaks down during perfusion or after the batteries have run out. In this study, the performance of hand cranking a roller pump was quantitatively assessed by an objective method using the ECCSIM-Lite educational simulator system. A roller pump connected to an extracorporeal circuit with an oxygenator and with gravity venous drainage was used. A flow sensor unit consisting of electromagnetic sensors was used to measure arterial and venous flow rates, and a built-in pressure sensor was used to measure the water level in the reservoir. A preliminary study of continuous cranking by a team of six people was conducted as a surprise drill. This system was then used at a perfusion seminar. At the seminar, 1-min hand-cranking drills were conducted by volunteers according to a prepared scenario. The data were calculated on site and trend graphs of individual performances were given to the participants as a handout. Preliminary studies showed that each person's performance was different. Results from 1-min drills showed that good performance was not related to the number of clinical cases experienced, years of practice, or experience in hand cranking. Hand cranking to maintain the target flow rate could be achieved without practice; however, manipulating the venous return clamp requires practice. While the necessity of performing hand cranking during perfusion due to pump failure is rare, we believe that it is beneficial for perfusionists and patients to include hand-cranking practice in periodic extracorporeal circulation crisis management drills because a drill allows perfusionists to mentally rehearse the procedures should such a crisis occur.     

Variations of the origin of the artery of the sinoatrial node in normal human hearts

Summary The artery of the sino-atrial node was studied in 100 normal human hearts after injection of each coronary artery with coloured gelatine containing a radiopaque substance. The hearts belonged to 69 males and 31 females, being 64 Caucasians and 36 non-Caucasians (Negroes and Mulattoes) whose age ranged from 7 to 80 years. Since the individuals had committed suicide or were victims of accidents, their hearts, after pathologists' evaluation, were considered normal. The sinoatrial node of the normal human heart is supplied by the right coronary artery more frequently (58%±4.9% of the cases) than by the left (42%±4.9). The right anterior medial atrial artery, originating from the right coronary at the level of the medial third of the right anterior quadrant of the atrial dome, is most frequently (50%±5) responsible for the blood supply of the sinoatrial node. Among the branches of the left coronary artery, the left anterior medial atrial artery, originating at the level of the medial third of the left. anterior quadrant of the atrial cupola, was the most frequent blood supplier (25%±4.3) of the sinoatrial node. The origin of the artery of the sinoatrial node from the proximal portion or trunk of the left coronary artery was less frequent (12%±3.2) than the origin from the circumflex artery (30%±4.5). Neither sex nor race influenced the variations of the origin of the sino-atrial node.

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Variations d'origine de l'artère du noeud sinu-atrial du coeur humain normal

Résumé L'a. du noeud sinu-atrial a été étudiée sur 100 coeurs humains normaux après injection de chaque a. coronaire à la gélatine colorée additionnée d'une substance radio-opaque. Les coeurs provenaient de 69 hommes et 31 femmes, 64 caucasiens et 36 non caucasiens (nègres et mulâtres) âgés de 7 à 80 ans. Ces sujets étant décédés par suicide ou des suites d'accidents, leurs coeurs ont été considérés comme normaux après examen anatomo-pathologique. Le noeud sinu-atrial du coeur humain est vascularisé par l'a. coronaire droite plus fréquemment (58 %±4,9) que par l'a. coronaire gauche (42 %±4). L'a. atriale antéro-médiale droite, issue de l'a. coronaire droite au niveau du tiers médial du quadrant antérieur droit du dôme atrial est l'artère la plus fréquemment en cause (50 %±5) dans la vascularisation du noeud sinuatrial. Parmi les branches de l'a. coronaire gauche, l'a. atriale antéro-médiale gauche, née au niveau du tiers médial du quadrant antérieur gauche du dôme atrial, était la branche la plus fréquemment en cause (25 %±4,3) dans la vascularisation du noeud sinu-atrial. La naissance de l'a. du noeud sinu-atrial à partir de la partie proximale ou du tronc de l'a. coronaire gauche était moins fréquente (12 %±3,2) que son origine à partir du rameau circonflexe (30 %±4,5). Les variations d'origine de l'a. du noeud sinu-atrial n'apparaissaient pas influencées par le sexe ou la race.

     

Priority of blood flow to splanchnic organs in humans during pre- and post-meal exercise

Cardiac output and superior mesenteric arterial flow in five healthy young men were followed using Doppler ultrasound techniques at rest and during 4 min bouts of bicycle exercise in both a pre- and a post-meal situation. The meal given was mixed and heavy, with an energy content (related to body size) of about 1400–1600 kcal (5.9-6.9 MJ). Two levels of exercise, 50–65 W and 150–200 W (about 75% of Vo_tmax), were tested, with the subjects cycling in a reclining position. Superior mesenteric arterial flow increased threefold, to about 1.11 min^-1, after the meal. During exercise in the fasting situation there were only modest changes in splanchnic vascular conductance, and moderate increases in superior mesenteric arterial flow were actually recorded. Exercise in the post-prandial state caused appreciable reductions in splanchnic vascular conductance, and a 38% reduction was observed during the most heavy exercise. However, not even such a decrease in conductance resulted in any definite reduction in superior mesenteric arterial blood flow, which was maintained at the pre-exercise level. Cardiac output increased by about 1.3 1 min^-1 after the meal. The exercise-induced increases in cardiac output were of the same order in the fasting and in the post-prandial state. Variance analyses showed the high cardiac output levels reached during postprandial exercise to be no different from levels that would be reached by pure summation of the changes caused by eating alone and by exercise alone. It is concluded that blood flow to the splanchnic organs in reclining man retains its high pre- and post-prandial priority during short exercise bouts of up to 75% of Vo_Smax.     

Myelin antigen reactive T cells in cerebrovascular diseases.

T cell reactivities to the putative autoantigens myelin basic protein (MBP), MBP peptides with amino acid residues 110-128 and 148-165, and myelin proteolipid protein (PLP) were examined in patients with acute ischaemic cerebrovascular disease (CVD) and, for comparison, in patients with inflammatory neurological diseases and other neurological diseases. A quantitative measure of these T cell reactivities was obtained by assessing numbers of T cells among blood and cerebrospinal fluid (CSF) mononuclear cells that secreted IFN-gamma in response to antigen in vitro. Higher numbers of T cells reactive with each of these four antigens were detected in peripheral blood from patients with CVD compared with patients of the two control groups. Among blood cells from the CVD patients, their average number was 2.3-4.2/10(5) mononuclear cells. MBP reactive T cells were several-fold enriched in the CSF of CVD patients. The findings strongly suggest that brain damage in context with acute CVD leads to an in vivo expansion of myelin reactive T cells.     

Uterotrophic effect of a saturated fatty acid 17-ester of estradiol-17beta administered orally to juvenile rats

In comparison to estradiol-17beta, the naturally synthesized estradiol-17beta-17-fatty acid esters are potent estrogens when administered subcutaneously. A lipophilic character of estradiol-17-esters could partially protect them from metabolic inactivation. In order to compare their relative estrogenic potency when administered orally, the uterotrophic response to different dosages (0, 2.5, 25, 250 and 2500 nmol/kg BW/day) of estradiol-17beta and estradiol-17beta-17-stearate was assessed in juvenile Sprague-Dawley female rats. Estrogens were administered by oral gavage once a day for 6 days. On the 7th day uterus and vagina were dissected, weighed, and examined microscopically. At 2.5 and 25 nmol/kg BW/day, no difference was detected in the uterus weight compared to control animals which received the vehicle alone (corn oil). At 250 nmol/kg BW/day, the uterotrophic response was maximal in estradiol-17beta-17-stearate-treated animals (x2.40-2.70), whereas it was moderate in estradiol-17beta-treated rats (x1.86) at the same dosage. This differential weight gain effect of estradiol-17beta-17-stearate was correlated with typical microscopic changes in uterus and vagina. The results are in favour of a stronger estrogenic effect of orally given lipoidal estrogens compared to estradiol-17beta. This could be explained by a slower but sustained absorption of estradiol-17beta released from estradiol-17beta-17-stearate by esterases and/or by a facilitated transfer of esters in the lymphatic circulation.     

Peripheral blood flows during colorectal distension in anaesthetised dogs

Distension of the descending colon elicits reflex cardiovascular responses, including increases in heart rate and arterial blood pressure. To study the relative contribution of vasoconstriction in individual vascular beds to this reflex response, experiments were performed on seven dogs anaesthetised with chloralose and instrumented with electromagnetic flowmeters around the superior mesenteric, the left renal and the left external iliac arteries. The colorectal portion of the intestine was distended at constant pressure (36.6 mm Hg, 4.9 kPa mean; range 25–50 mm Hg, 3.3–6.7 kPa) with warm Ringer solution for periods of 2 min. After a set of control distensions, the experiments were performed whilst the reflex rise in arterial pressure was prevented by removal of blood from the arterial tree. In control distensions arterial pressure increased by 11.3±1.5 mm Hg, 1.51±0.12 kPa (mean±SEM). In distensions at constant arterial pressure, peripheral blood flows were altered to different extents in the three territories studied: vascular resistance increased by 30.8±5.6% (P<0.01) in the mesenteric, by 4.1±1.5% (P<0.03) in the renal, and by 15.2±6.8% (NS) in the external iliac bed. We conclude that colorectal distension may reflect activation of a function-specific pathway of the sympathetic nervous system, which leads to much greater vasoconstriction in the splanchnic circulation than in renal or musculocutaneous circulations.     

Hypoxic pulmonary vasoconstriction is heterogeneously distributed in the prone dog

Hypoxic pulmonary vasoconstriction (HPV) is thought to protect gas exchange by decreasing perfusion to hypoxic regions. However, with global hypoxia, non-uniformity in HPV may cause over-perfusion to some regions, leading to high-altitude pulmonary edema. To quantify the spatial distribution of HPV and regional PO2 (PRO2) among small lung regions (approximately 2.0 cm3), five prone beagles (approximately 8.3 kg) were anesthetized and ventilated (PEEP approximately 2 cm H2O) with an F1O2 of 0.21, then 0.50, 0.18, 0.15, and 0.12 in random order. Regional blood perfusion (Q), ventilation (VA) and calculated PRO2 were obtained using iv infusion of 15 microm and inhalation of 1 microm fluorescent microspheres. Lung pieces were clustered by their relative blood flow response to each F1O2. Clusters were shown to be spatially grouped within animals and across animals. Lung piece resistance increased as PRO2 decreased to 60-70 mmHg but dropped at PRO2's < 60mmHg. Regional ventilation changed little with hypoxia. HPV varied more in strength of response, rather than PRO2 response threshold. In initially homogeneous VA/Q lungs, we conclude that HPV response is heterogeneous and spatially clustered.     

Cerebrovascular stenoses with cerebral infarction in a child with Williams syndrome

We report on a patient with Williams syndrome who suffered a cerebrovascular accident. Clinical evaluation demonstrated the presence of carotid and cerebral arterial stenoses. We believe these lesions led to acute cerebrovascular ischemia and a non-hemorrhagic cerebral infarction. It is possible the stenoses were exacerbated by a vasculitis. The stenoses were identified by both invasive and noninvasive imaging studies. These studies may have a role in the evaluation of persons with Williams syndrome. © 1994 Wiley-Liss, Inc.     

急性脑血管病之脑电地形图与脑CT对比研究

本文报告了急性脑血管病的脑电地形图与脑CT的对比研究。介绍了急性脑血管病的脑电地形图改变,对脑电地形图与脑CT在急性脑血管病诊断上的优劣进行了对比,进一步讨论了脑电地形图在急性脑血管病中的临床应用价值。