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At least 325 records · Page 18Linked to original sources
PubMed2001

Separation of omphalopagus conjoined twins using combined caudal epidural-general anesthesia.

PURPOSE: To describe the anesthetic management of newborn omphalopagus conjoined twins undergoing a series of diagnostic and surgical procedures which culminated in successful separation at one month of age. CLINICAL FEATURES: Evaluations of the extent of shared organ systems were carried out without the need for anesthesia. The twins were anesthetized twice, once for insertion of skin expanders, and later for surgical separation. Various airway management techniques were utilized. To facilitate surgical separation, caudal epidural catheters were inserted in an effort to provide both operative and post-operative analgesia. In addition, prior to the induction of anesthesia, the extent of cross-circulation between twins was assessed. CONCLUSION: Caudal epidural catheters can be used to provide both operative and post-operative analgesia. Early extubation, another benefit of regional analgesia, was not achieved because both twins developed respiratory failure in the immediate postoperative period. Testing for the extent of cross-circulation between twins proved valuable, allowing for detailed scripting of the complex induction sequence and airway management.

Anesthesia, Epidural↗
PubMed1993

Different central areas involved in the mechanisms of morphine antinociception in the mouse and the rat.

The antinociceptive effect of morphine quantitated by the tail-flick (TF) response was studied in mice and rats with various preparations, including: precollicular transection, partial and complete anemic decerebration, vertebral artery infusion, cross-circulation, spinal ligation, spinalization with dura mater intact and spinal subarachnoid infusion. In mice, either precollicular transection or partial anemic decerebration abolished or greatly reduced the morphine antinociceptive action (MAA). However, in rats, neither precollicular transection nor complete anemic decerebration caused any significant reduction in MAA. Studies of vertebral artery infusion and cross-circulation in both species indicated that opiate-sensitive antinociceptive receptors (OSAR) were present in the hindbrain. Although, spinal ligation eliminated MAA in both species, spinalization with dura mater intact only abolished the MAA in rats. On the other hand, studies of spinal subarachnoid infusion showed that only spinal antinociceptive neurons of mice were highly sensitive to the enzyme-resistant enkephalin (Enk) analog. From all these results suggested that both pre- and post-collicular structures are necessary for MAA in the mouse, however, in the rat only the post-collicular structures are essential, furthermore, the humoral pathway seems to play a more important role than the neural pathway in the inhibition of the TF response in the mouse but just the opposite in the rat. Therefore, it is concluded that the mechanisms of MAA are different between the mouse and the rat. The possible mechanisms of MAA in both species were discussed.

Analgesia↗
PubMed1999

Total Ca handling in canine mild Ca overload failing heart.

We analyzed total Ca handling of the left ventricle (LV) in the mildly failing heart preparation induced by a temporary intracoronary Ca overloading intervention in eight excised and cross-circulated canine hearts. This Ca intervention consisted of interruption of coronary blood perfusion by Ca-free oxygenated Tyrode perfusion for 10 min followed by high-Ca (16mmol/l) oxygenated Tyrode perfusion for 5 min. This intervention decreased the LV contractility index, Emax (end-systolic maximum elastance), by 40% after restoration of the blood cross-circulation. We expected a Ca overload or paradox failing heart resembling the postischemic stunned heart and being characterized by an increased O2 cost of Emax. However, LV O2 consumption under mechanically unloading conditions decreased by 30% from control without increasing the O2 cost of Emax. To obtain a mechanistic view of this failing heart, we investigated cardiac total Ca handling by our integrative analysis method. In this method, we obtained the internal Ca recirculation fraction (RF) from the decay beat constant of the postextrasystolic potentiation following each sporadic spontaneous extrasystole in these failing LVs. We combined the RF with the decreased Emax and the unchanged O2 cost of Emax in our recently developed formula of total Ca handling. We found that these failing LVs had a slightly but significantly increased RF accompanied by either a slightly increased futile Ca cycling or a slightly decreased Ca reactivity of Emax, or both. Any of these three possible changes can account for the unchanged O2 cost of Emax. This result indicates that the present mildly failing heart has not yet fallen into a typical Ca overload or paradox by the temporary Ca overloading intervention.

Animals↗
PubMed1978

Compensatory hyperplasia with increasing loss of renal mass.

When a rat with two kidneys is cross-circulated with an anephric rat, compensatory renal hypertrophy occurs as indicated by an increased ratio of RNA to DNA within 6 hours and an increased ratio of kidney weight to body weight within 12 hours. Removal of three kidneys between the rats further increases residual renal mass and RNA/DNA after 24 and 48 hours of cross-circulation as compared with results of removing two kidneys. Trinephrectomy triples the mitotic index and doubles the proliferative index. Increasing the magnitude of renal loss causes appreciable hyperplasia as well as increasing the magnitude of compensatory renal hypertrophy.

Animals↗
PubMed2005

[Application and reliability of balloon occlusion test in treatment of cerebrovascular diseases].

OBJECTIVE: To study the reliability of applying balloon occlusion test (BOT) to evaluate the compensation capacity of cerebral collateral circulation, and investigate the validity of different criterion about BOT and techniques to improve the security of BOT. METHODS: A retrospective analysis was conducted on the results of 86 patients, 39 males and 47 females, aged 49.8 (13 - 72), 67 suffering from intracranial aneurysm and 19 from traumatic carotid cavernous fistula, who received BOT, and on the results of 38 of the 66 patients who accepted artery occlusion after the BOT. RESULTS: The positive rate of diagnosis was 10.47% and the negative rate was 89.53% by conventional BOT; whereas the positive rate of diagnosis was 36.05% and the negative rate was 63.95% with combined cross circulation and conventional test. The brain ischemia rate after cerebral artery occlusion therapy was 8.33%. The BOT-related complication rate was 3.49%. CONCLUSION: (1) The current BOT technique can basically provide reliable results. (2) The cross circulation test and hypotensive provocative test can effectively improve the specificity of BOT. (3) More perfect BOT criterion for the prediction of cerebral tolerance is still to be worked out. Combination of the conventional method and advanced imaging technique and search for an objective and quantificational criterion would be of reward.

Adolescent↗
PubMed1996

Anaesthetic managements for conjoined twins with complex cardiac anomalies.

PURPOSE: To describe the perioperative assessment and anaesthetic management for surgical separation of three sets of conjoined twins with complex cardiac anomalies threatened with arterial desaturation and haemodynamic instability. CLINICAL FEATURES: Three sets of conjoined twins, one omphaloischiopagus, one omphalopagus, and one thoraco-omphalopagus, were considered for separation during the perinatal or infantile period. Preoperative functional evaluation including continuous pulse oximetry, capnography, and cardiac electrophysiological studies were considered to be as important as anatomical evaluation of the cardiac anomalies and cross-circulation by angiography in assessing the feasibility of surgical separation. Ipsilateral infusion of prostaglandin E1 and phenylephrine were applied to the cyanotic and healthy twins respectively, to restore arterial oxygenation intraoperatively and to avoid profound hypoxaemia. CONCLUSION: Surgical separation and anaesthesia should be well planned and rehearsed before clinical deterioration of the weaker twin. Aggressive pharmacological intervention and understanding of the cross-circulation pathophysiology is necessary to manage critical situations during surgical separation and in the postoperative period.

Anesthesia↗
PubMed1988

Cardiac cooling increases Emax without affecting relation between O2 consumption and systolic pressure-volume area in dog left ventricle.

We studied the effects of cardiac cooling by 7 +/- 2 degrees C (SD) from 36 degrees C on both contractility index (Emax) and the relation between O2 consumption per beat (VO2) and systolic pressure-volume area (PVA) of the left ventricle in the excised cross-circulated dog heart preparation. PVA represents the total mechanical energy generated by a contraction. The VO2-PVA relation divides measured VO2 into unloaded VO2 and excess VO2. The slope of the VO2-PVA relation represents inversely the efficiency of the contractile machinery to convert chemical energy from the excess VO2 to total mechanical energy. Cooling is known to decrease myosin ATPase activity (Q10 of 2-3), which in turn is expected to increase the chemomechanical efficiency of cross bridges. Therefore, we expected an increase in the efficiency and hence a decreased slope of the VO2-PVA relation with cooling. The cooling increased Emax by 46 +/- 13% and the time to Emax by 45 +/- 27%. Pacing rate was constant or had to be slightly decreased to avoid arrhythmias with cooling. We found that neither the slope of the VO2-PVA relation nor unloaded VO2 significantly (p greater than 0.05) changed with the cooling. This result contradicts the expected increase in the efficiency with cooling. We conclude that cardiac cooling by 7 degrees C from 36 degrees C does not increase the efficiency of the contractile machinery in excised cross-circulated dog left ventricle.

Animals↗
PubMed2004

Regional myocardial perfusion under exchange transfusion with liposomal hemoglobin: in vivo and in vitro studies using rat hearts.

The purpose of this study was to test the hypothesis that exchange transfusion with liposomal hemoglobin (LH) reduces the microheterogeneity of regional myocardial flows while sustaining cardiac function. Neo Red Cell mixed with albumin was used as the LH solution, in which the LH volume fraction was 17 approximately 18% and hemoglobin density was nearly two-thirds smaller than in rat blood. Regional myocardial flows in left ventricular free walls were measured by tracer digitalradiography (100-mum resolution) in anesthetized rats with or without 50% blood-LH exchange transfusion. Within-layer flow distributions showed lower heterogeneity with (n = 8) than without (n = 8) LH transfusion. No extravasation of hemoglobin was confirmed by 3,3-diaminobenzidin staining (n = 2). Carotid flow increased by 68% due to LH transfusion, whereas arterial pressure and heart rate remained unchanged. On the other hand, cross-circulated rat hearts (n = 7) were used to evaluate the effects of 50% blood-LH exchange on coronary flow and tone preservation under 300-beats/min pacing and 100-mmHg perfusion pressure. Blood-LH exchange caused a 71% increase of coronary flow and 10% decrease of percent flow increase during hyperemia after 30-s flow interruption. Myocardial O(2) supply and consumption increased by 9% and 10%, respectively, whereas myocardial O(2) extraction remained unchanged. The large increases of in vivo carotid flow and coronary flow in cross-circulated hearts due to LH coperfusion could be explained by the reduction of apparent flow viscosity. These results suggest that under LH coperfusion, the microheterogeneity of myocardial flows decreases with increased coronary flow while fairly preserving coronary tone and cardiac function.

Animals↗
PubMed1988

Cardiotonic activity of 5-methyl-6-(4-pyridyl)-2H-1,4-thiazin-3(4H)-one hydrochloride (ZSY-27).

Cardiotonic activity of a new, non-catecholamine and non-glycoside positive inotropic agent, 5-methyl-6-(4-pyridyl)-2H-1,4-thiazin-3(4H)-one hydrochloride (ZSY-27), was investigated in isolated guinea pig left atria, cat right ventricular papillary muscle and cross-circulated excised dog papillary muscle preparations, and in anesthetized open-chest dogs. In electrically driven guinea pig left atria and cat papillary muscle preparations, ZSY-27 (3 x 10(-6)-10(-4) M) increased the developed tension in a concentration-related manner. The positive inotropic effect of ZSY-27 was not blocked by propranolol (3 x 10(-8) M) in the guinea pig atria, but was significantly inhibited by carbachol (5 x 10(-6) M) in cat papillary muscle preparations. The positive inotropic effect of ZSY-27 was comparable to that of milrinone in guinea pig atria. ZSY-27 (0.01-3 mg) increased dose-dependently the developed tension in cross-circulated excised dog papillary muscle preparations as well. In anesthetized dogs, ZSY-27 (0.03-1 mg/kg, i.v.) produced a dose-dependent increase in left ventricular contractile force and a decrease in blood pressure, while the increase in heart rate was relatively small. The pharmacological profile of ZSY-27 in anesthetized dogs was similar to that of milrinone. These results suggest that ZSY-27 is potent cardiotonic agent with vasodilator activity and its effect may be partially due to an increase in the intracellular adenosine 3',5'-cyclic monophosphate level.

Animals↗
PubMed1988

Isolated dog hearts prepared in cold tyrode solution and reperfused with arterial blood are functionally and ultrastructurally normal.

Isolated dog whole heart preparations run by means of cross-circulation with support dogs were prepared in two different ways. In one way the donors' hearts were quickly removed, and cannulation of their major vessels, insertion of a latex balloon into the left ventricle, etc. were all done in cold Tyrode solution in the condition of heart-anoxia within 30 min and then reperfused with arterial blood of support dogs (Group A). In the other, cannulation of the major vessels of the donors' hearts were done in the state of "beating heart" (Group B). In these two kinds of preparations we compared basal cardio-coronary measurements (coronary blood flow, left ventricular pressure (LVP), its first derivative (LV dP/dt) and myocardial oxygen consumption (MVO2) and ultrastructure of the myocardium at various periods of the experiments. There were no significant differences in these cardio-coronary measurements and ultrastructural findings. Furthermore, Group A preparations kept stable levels of cardio-coronary measurements for 5 hr or more and responded normally to isoproterenol. Therefore, isolated, blood-perfused dog whole hearts prepared in cold Tyrode solution and reperfused by means of the cross-circulation method would be useful for physiological, pharmacological and biochemical studies.

Animals↗
PubMed2003

[Fifty years of the heart-lung machine. Report on the pioneers and heroes and about the circumstances that led to the great invention, which allowed the treatment, and in many cases, the cure of heart illnesses].

In 1953 DNA was discovered and the Everest was conquered but also a great invention was developed: the heart-lung machine, which allowed the treatment, and in many cases, the cure of most cardiovascular illnesses. In fact, on May 6, 1953 John Gibbon crowned with success the work of his entire life closing for the first time an atrial septal defect in a young woman using a heart-lung machine of his own invention. Before that, surgeons had explored other roads like hypothermia, cooling the patient in a cold water tub and then rapidly performing the surgical correction of a heart malformation. After his first success, the following 4 patients of Gibbon died, which led him to abandon heart surgery and produced a generalized pessimism about extracorporeal circulation. However, a year later Walton Lillehei reverted this situation with the introduction of controlled cross-circulation in which a patient, usually a child, was connected to a "donor", usually his father or mother, whose heart and lung served as a pump and oxigenator, allowing the performance of open heart surgery. Finally, it was Lillehei again who a year later introduced the bubble oxigenator, simple and inexpensive, opening the doors of open heart surgery to all surgeons around the world. For this, and many other reasons, Walton Lillebei is considered by most surgeons as the "Father of Open Heart Surgery". Lillehei visited Chile in 1963 and operated on a patient in the surgical theaters of the Hospital Clínico de la Universidad Católica and was named an Honorary Member of the School of Medicine of this University. Before that, in 1957 Helmut Jaeger at the Hospital Luis Calvo Mackenna performed the first successful surgical closure of an atrial septal defect with extracorporeal circulation in Chile using a De Wall-Lillebei bubble oxigenator.

Cardiac Surgical Procedures↗
PubMed1991

Is the humoral renal antihypertensive activity of the spontaneously hypertensive rat (SHR) reset to the high blood pressure?

The kidneys have a humoral antihypertensive system, located in the renal medulla and presumably antagonizing the pro-hypertensive renin-angiotensin system. Medullipin I and II and maybe platelet activating factor (PAF), seem to be the mediators of this system, known to be activated after reversal of renovascular hypertension or when the perfusion pressure to a normotensive kidney is suddenly elevated. The present study was undertaken to investigate whether this system is functioning also in the spontaneously hypertensive rat (SHR), and if it is then reset in proportion to the increased mean arterial pressure (MAP). Isolated kidneys from spontaneously hypertensive rats and from Wistar Kyoto rats (WKY) were cross-perfused in vivo from anaesthetized intact Wistar Kyoto rat 'donors'. After 30 min of perfusion at 100 mmHg the perfusion pressure to the isolated kidneys were, for 60 min, either kept unaltered at 100 mmHg or, for the Wistar Kyoto rat kidneys, increased to 150-200 mmHg and, for the spontaneously hypertensive rat kidneys, raised to 200 or 250 mmHg. The results show that the humoral antihypertensive system is present also in spontaneously hypertensive rat kidneys, but is here reset upwards to or even beyond the elevated MAP level. Furthermore, all mean arterial pressure reductions caused by high-pressure perfusion of Wistar Kyoto and spontaneously hypertensive rat kidneys were accompanied by reductions in heart rate (HR) in the 'donors', in agreement with previous observations after reversing renal hypertension and after i.v. medullipin I injection. In fact, in spontaneously hypertensive rat kidneys, the 'incretory' depressor mechanism appears to be more markedly reset upwards than is the 'excretory' depressor mechanism inherent in pressure diuresis with consequent salt-volume elimination. In conclusion spontaneously hypertensive rats, like Wistar Kyoto rats and Wistar rats, have a humoral antihypertensive system in the kidneys, but it is reset upwards even beyond the elevated mean arterial pressure level in spontaneously hypertensive rats. The combination of a depressor response and reduced heart rate in the 'donors' renders further evidence that the medullipins are the principal, though probably not the only, humoral antihypertensive factors released from the cross-circulated kidneys.

Animals↗