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At least 451 records · Page 25Linked to original sources
PubMed1975

The superiority of aortic cross-clamping with profound local hypothermia for myocardial protection during aorta-coronary bypass grafting.

Two different operative techniques for aorta-coronary bypass grafting were utilized in two comparable groups of patients. In one group (155 patients) distal anastomoses were carried out with the aorta cross-clamped and myocardial protection provided by profound local hypothermia (clamped group). In a second group (149 patients) distal anastomoses were carried out with the aorta unclamped and the left ventricle fibrillating and vented (unclamped group). Mortality rates were similar in the two groups (0.6 per cent in clamped group versus 1.3 per cent in unclamped group). The incidence of perioperative infarction was 15 per cent in the unclamped group and 8 per cent in the clamped group (p less than 0.05). Postoperative serum glutamic oxaloacetic transaminase (SGOT) and lactic dehydrogenase (LDH) levels were significantly higher for the first 4 postoperative days in the unclamped group than in the clamped group. Hemodynamic studies in a subset of each group revealed no important differences in left ventricular function in the immediate postoperative period. The data demonstrate that in patients undergoing aorta coronary bypass grafting, performance of distal anastomoses with aortic cross-clamping and profound local hypothermia results in less intraoperative myocardial injury than performance of distal anastomoses in the perfused, fibrillating, and vented left ventricle.

Aspartate Aminotransferases↗
PubMed2001

Alterations in carbon dioxide release during abdominal aortic clamping for aneurysmal or occlusive repair.

BACKGROUND: Application and removal of an infrarenal aortic clamp is associated with changes in oxygen consumption, especially when collateral perfusion is limited. Carbon dioxide production during abdominal aortic clamping is expected also to change. The aim of this study was to evaluate the alterations of CO2 release during abdominal aortic surgery. METHODS DESIGN: prospective study. SETTING: University Hospital, Greece. PATIENTS: 17 patients undergoing abdominal aortic aneurismal (AAA) repair and 8 patients undergoing repair of aortoiliac occlusive disease. INTERVENTION: intraoperative record or calculation of PaCO2, PetCO2, PECO2, VD, VDalv, and VCO2. Patients with aneurysms were randomly divided to have constant ventilation (group AA) or modified ventilation to preserve normocapnia (group AB) during clamping. Ventilation was kept constant in the occlusive patients group (group OD). RESULTS: Patients with AAA showed a significant decrease of VCO2 during clamping and an elevation after unclamping in both groups (AA and AB), with no difference of statistical importance between them. During clamping, PetCO2/ PaCO2 ratio was decreased and VDalv was increased especially in group AA, while unclamping produced the opposite effect. Occlusive patients showed insignificant alterations. CONCLUSIONS: Our results suggest that, the calculated alveolar dead space is only an indicator of the true V/Q in patients with AAA, because it is strongly dependent on the CO2 load to the lungs, which is markedly altered in the same period. The modification of ventilation during clamping based only on PetCO2 and not on arterial sampling, could possibly lead to hypercarbia in these patients.

Aged↗
PubMed2002

Predictive value of conventional computed tomography in determining proximal extent of abdominal aortic aneurysms and possibility of infrarenal clamping.

The present study aimed to evaluate the diagnostic reliability of computed tomography in determining the proximal extent of abdominal aortic aneurysms and the possibility of infrarenal clamping. Preoperative computed tomographic findings, together with the operative data for 95 patients, were retrospectively analyzed in light of the operative findings. Eighty-nine (93.68%) of the patients were men and 6 (6.32%) were women, with a mean age of 66.27 +/- 18.14 years. Diagnosis of infrarenal aneurysm by computed tomography was confirmed at the time of surgery in 91 (95.79%) of 95patients. The negative-predictive value of computed tomography in detecting supra-aneurysmal renal arteries was found to be 95.79%. The specificity was 98.91%. Infrarenal cross-clamping was performed in 59 (62.11%) of 95 patients, whose aortic segments between the renal artery orifices and the proximal borders of the aneurysms had a mean length of 26.4 +/- 7.11 mm by computed tomography Suprarenal clamping was required in 36 (37.89%) of the 95 patients, whose aortic segments had a mean length of 12.7 +/- 3.48 mm. We conclude that conventional computed tomography is reasonably accurate in determining the proximal extent of abdominal aortic aneurysms. Although there is a high rate of error in determining the possibility of infrarenal clamping when no specific measurements are taken, infrarenal clamping can be planned when measurement by computed tomography shows a length of > or = 26 mm between the renal arteries and the proximal extent of the aneurysm. In patients with shorter aortic segments, suprarenal aortic clamping should be considered.

Aged↗
PubMedDate not supplied

Continuous versus intermittent portal triad clamping during hepatectomy in cirrhosis. Results of a prospective, randomized clinical trial.

BACKGROUND/AIMS: It has been shown that hepatic pedicle clamping is a safe and effective technique to control bleeding during liver resection. A major drawback can be the induction of liver ischemia and splanchnic venous stasis. METHODOLOGY: This randomized controlled clinical trial compared continuous and intermittent hepatic pedicle clamping during resection of the cirrhotic liver in order to determine which technique is more effective in reducing operative blood loss and producing less ischemic injury. In 18 patients we performed continuous portal triad clamping during liver transection while in 17 patients we performed intermittent clamping. The two groups matched for extent of resection. Serial hepatic function tests were performed on postoperative day 1, 3 and 7. RESULTS: No significant difference was found between the two groups in terms of operative findings. Operative mortality was 5.7% (2 patients). Six patients (17.3%) had postoperative complications. There were no significant differences between the two groups with regard to postoperative liver function tests and coagulation profile. CONCLUSIONS: Continuous and intermittent clamping are both effective in reducing blood loss during hepatectomy in cirrhosis. The two techniques seem to be comparable in terms of ischemic injury. Our findings suggest that intermittent portal triad clamping may not be necessary. As this is contrary to the normal expectancy, additional studies may be needed.

Aged↗
PubMed1992

[Air pressure vascular clamp. Experimental study and clinical application].

An air pressure vascular clamp was designed for vascular surgery. On femoral arteries of 90 rats, vascular injury and anastomosis experiments were made to compare this clamp with 2 other vascular clamps commonly used, and the pressure on blood vessels from different clamps was determined. Examination with operating, light and electron microscopes showed that the number of vascular injuries and their degree were the least after use of this clamp, the pressure of which could be adjusted just to block blood flow, suitable for blood vessels of different calibers. Satisfactory results have been obtained through its clinical application in 43 patients having 119 vascular anastomoses. It is thought that the unobstructed rate of vascular anastomosis can be raised by the application of this vascular clamp, especially for vessels of small caliber and long period of compression.

Adolescent↗
PubMed2005

[Effect of propofol on spinal cord apoptosis associated with aortic cross-clamping in rabbits].

OBJECTIVE: To investigate the effect and mechanism of propofol on the spinal cord apoptosis associated with aortic cross-clamping in rabbits. METHODS: Twenty-four rabbits were randomly divided into sham operation group (A), ischemia/reperfusion group (B) and propofol group (C). In group B and C, the infrarenal aorta was clamped for 40 minutes followed by 7 days reperfusion. Ten minutes before clamping, group C was given propofol 5 mg/kg intravenously and continued at a rate of 20 mg x kg(-1)x h(-1) until unclamping. The aorta was not clamped in group A. The plasma concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) were determined at 10 minutes before clamping (C-10), before unclamping (C40), at 60 minutes (R60) and on the 7th day (R7 d) unclamping. Apoptotic spinal cord cells and expressions of Bax, Bcl-2 protein were measured by immunohistochemical technique. RESULTS: (1)The concentrations of MDA after ischemia and reperfusion in group B were increased significantly compared with C-10 and those in group A (P<0.05 or P<0.01), which in group C were significantly lower than those in group B (P<0.05), but not in group A. Changes in SOD activity were opposite to those in MDA contents in various groups. (2)The expressions of Bax protein in group B were significantly increased compared with those in group A (P<0.05), while the expression of Bcl-2 protein decreased. In group C, Bax protein expression was markedly lower than those in group B and higher than those in group A (P<0.01 and P<0.05), the expression of Bcl-2 was higher than those in groups B and A (both P<0.01). (3)The number of apoptosis cells in group B was much higher than that in group A, which in group C was much lower than that in group B, but higher than that in group A. (4)The ratio of paralysis in group C was significantly lower than that in group B with a high neurologic score (both P<0.01). CONCLUSION: Propofol can reduce the spinal cord apoptosis associated with aortic cross-clamping in rabbits. The possible mechanism is related to the effect of decreasing Bax expression, increasing Bcl-2 expression, and enhancing antioxidation.

Animals↗
PubMed1990

[Intraoral dental fixation of an endotracheal tube using a cofferdam clamp].

UNLABELLED: Extraoral tape fixation of the orotracheal tube for general anesthesia is a major problem in maxillofacial surgery. First of all, surgical access to the perioral and nasal region is handicapped by the tape covering and distracting the skin, especially in those cases where no nasotracheal intubation is possible; furthermore, blood, saliva, and disinfectant fluid interfere with reliable adhesion of the tape. A method of intraoral dental fixation of the orotracheal tube by a rubber dam fixation clamp is presented. The rubber dam isolates teeth against the oral cavity, providing a dry operative field to the dentist. The set of clamps, each designed according to the individual anatomy of the different teeth, is usual in the dental trade. After intubation the selected clamp is placed on the tooth by means of the forceps. The tube is laid on the clamp and tied on by a silk thread (2 x 0), which is inserted through the clamp's holes. We recommend fixation to the teeth in the mandible to avoid tension load, which could strain teeth in the maxilla; as far as possible only teeth without any impairment (e.g. loosening) should be selected. CONCLUSION: The method of intraoral dental fixation of the orotracheal tube by a rubber dam clamp offers the following advantages: (1) the surgeon, especially the maxillofacial surgeon, has a good view of the perioral region and free access for surgery; there is (2) no skin distraction or irritation by tape; there is (3) reliable tube fixation even for patients with allergy to adhesive materials; there is (4) no solution of tape fixation by blood, saliva, or disinfectant fluid; and (5) silk sutures cannot be subjected to strain when solving tape fixation.

Humans↗
PubMed1990

Improvement in thoracic aortic pressure after proximal aortic cross-clamping by balloon occlusion of the distal aorta.

Spinal cord hypoperfusion injury is a devastating complication of cross-clamping the proximal thoracic aorta. The collateral circulation around the cross-clamp is generally poorly developed, and the run-off is immense, resulting in extremely low thoracic aortic and spinal cord perfusion pressures. The authors postulated that balloon occlusion of the abdominal aorta might confine this reduced collateral flow around the cross-clamp to the thoracic aorta. In 8 of 16 dogs subjected to aortic cross-clamping of the aorta just beyond the arch vessels, the abdominal aorta was also occluded by a balloon. Thoracic aortic pressure and spinal cord perfusion pressure were significantly higher in the animals with aortic balloon occlusion than in those without balloon occlusion (77 +/- 8 mm Hg versus 26 +/- 1 mm Hg, p less than 0.01, and 67 +/- 8 mm Hg versus 18 +/- 2 mm Hg, p less than 0.01, at 10 minutes after cross-clamping). Abdominal aortic balloon occlusion increases thoracic aortic pressure after the aorta is cross-clamped proximally. Further studies are necessary in primates to assess the effect of this procedure in spinal cord perfusion and the rate of paraplegia.

Animals↗
PubMed1987

[Preoperative assessment of clamping in carotid artery surgery and adaptation of the operative technic].

A retrospective study of 150 consecutive patients undergoing revascularization of internal carotid artery for atheromatous lesion of carotid bifurcation, included analysis of collaterals being compressed by common carotid artery simulating clamping. Two exploratory procedures had been applied routinely: global suprasigmoid digital subtraction angiography and Doppler velocimetry. Two groups of patients could be defined: clamping without risk (95.4%) and clamping at risk (4.6%). For the group of clamping at risk a surgical strategy is proposed allowing clamping without shunt by bypass between subclavian and internal carotid arteries of by bypass between common and internal carotid arteries because of the external carotid artery collaterals left untouched. A shunt is only necessary when the latter artery is occluded. Results of this series of patients explored in this way and operated upon confirmed these data: no clamping accident in the 1st group, one transient ischemic accident in the 2nd.

Adult↗
PubMed1988

Inferior and superior vena caval blood flows during cross-clamping of the thoracic aorta in pigs.

Changes in blood flow through the inferior and superior venae cavae during cross-clamping of the thoracic aorta just above the diaphragm were studied in 28 miniature pigs anesthetized with enflurane titrated to maintain systemic arterial blood pressure close to normal values. Surgical preparation included sternotomy with subsequent placement of a noncannulating electromagnetic probe around the ascending aorta and a cannulating electromagnetic probe in the transected inferior vena cava. Superior vena caval flow was calculated as the difference between aortic flow and inferior vena caval flow. Clamping of the thoracic aorta alone (n = 10) was accompanied by severe arterial hypertension, a dramatic decrease in inferior vena caval flow, and an increase in superior vena caval flow, which resulted in a moderate increase in aortic flow. Simultaneous clamping of the thoracic aorta and inferior vena cava (n = 13) was accompanied by no significant change in arterial pressure or superior vena caval flow. The oxygen content in mixed venous blood significantly (p less than 0.05) increased from 9.5 +/- 1.1 to 13.4 +/- 1.8 ml.dl-1 in animals undergoing clamping of the thoracic aorta only, but did not change significantly in animals subjected to simultaneous clamping of the aorta and inferior vena cava. The study demonstrates a substantial increase in superior vena caval flow during cross-clamping of the thoracic aorta. Further studies elucidating the mechanism of the observed changes are required.

Animals↗
PubMed1986

New upper and lower clamps for use in anterior resection of the rectum by hand suture or stapling techniques.

New occlusive clamps have been designed to facilitate anterior resection of the rectum. A T shaped upper occlusive clamp with centrally placed arms, curved transverse end and its total length and light weight provide more secure control of the intestine and allows the surgeon a less obstructed view of the distal site of section than the traditional L shaped rectal clamps. A lower occlusive clamp has been designed to obviate many of the inherent problems of controlling and suturing a rectal stump in the depths of the pelvis. Main concerns and technical troubles are retraction of the stump, loss of control of the flabby rectal remnant and difficulty handling the anterior and posterior walls as the surgeon attempts to make the anastomosis. The lower clamp keeps the rectum from retracting and the proximal cut end is held open by four stay sutures to wings on the right and left blades of the clamp. It is used to facilitate the placement of a purse-string suture in the EEA stapling technique or in a hand sutured anastomosis.

Humans↗
PubMedDate not supplied

[Cord clamping at birth - considerations for choosing the right time (author's transl)].

UNLABELLED: From the historical point of view, cord clamping has been performed in natural child birth some time after the fetus has been delivered and after the expulsion of the placenta. In 1877 already Hayem could show that in late cord clamping (LC) the concentration of erythrocytes in the newborn blood is elevated if compared to early clamping (EC) of the unbilical cord. It was concluded that is was a result of placental transfusion. The underlying mechanism of the placental transfusion is the hydrostatic pressure between the placenta and the fetus, supported by uterine contraction and the time of cord clamping after birth. Placental transfusion is diminished if cord clamping is performed in less than 180 sec and if the newborn baby is positioned 20 cm and more above the placental insertion. The newborn responds to placental transfusion with an increase of hemoglobin and hematocrit, an elevated blood pressure, although significant differences in cardiac output could not be established. Renal function is increased and effective renal blood flow associated with the blood volume of the newborn. In cases of caesarean section a higher incidence of respiratory distress occurs if placental transfusion does not take place. In utero placental transfusion occurs if the fetus is hypoxic obviously to increase the oxygen supply to the fetal tissue. IN CONCLUSION: "In order to give the newborn the blood, that it need physiologically cord clamping should be performed not immediately after birth, but one should wait as long until the umbilical vein has been empty and is collapsed." (Bumm 1902).

Acidosis↗
PubMed1993

Periventricular/intraventricular hemorrhage following early and delayed umbilical cord clamping. A randomized controlled trial.

OBJECTIVE: To test the hypothesis that early compared with delayed clamping of the umbilical cords of low-birthweight babies may increase the incidence of periventricular/intraventricular hemorrhage (PVH/IVH). DESIGN: Randomized controlled trial. SETTING: The labor wards of 3 teaching hospitals of the University of the Witwatersrand, Johannesburg. PATIENTS: Women expected to give birth to babies weighing less than 2000 g. INTERVENTIONS: Allocation by randomly ordered, sealed cards to a policy either of clamping the umbilical cord immediately after delivery, or, if possible, delaying cord clamping for 1 to 2 min. MAIN OUTCOME MEASURES: Ultrasound diagnosis of PVH/IVH about 24 h after birth by an observer blind to the allocation of each patient. RESULTS: PVH/IVH was diagnosed in 8/40 (20%) of neonates following delayed umbilical cord clamping and 11/46 (24%) following early cord clamping (odds ratio 0.80; 95% confidence interval, 0.29 to 2.20). CONCLUSIONS: This study does not confirm that early clamping of the umbilical cord may contribute to the initiation of PVH/IVH in low-birthweight neonates, but further studies are required before the hypothesis can be rejected with confidence.

Cerebral Hemorrhage↗
PubMed1993

[Experimental studies on retrograde cerebral perfusion: efficacy of clamping of the venous blood flow through IVC cannula].

Retrograde cerebral perfusion (RCP) is used to prolong the safe period of circulatory arrest under profound hypothermia. However, this technique now varies in some maneuvers at different institutions. This study investigated the effects on cerebral metabolism of clamping blood flow through the IVC cannula during RCP using fourteen adult mongrel dogs. During circulatory arrest, RCP by way of the bilateral internal maxillary vein was performed. In seven dogs, blood flow was drained through IVC cannula (IVC-drained group) and in the other seven dogs, the blood flow was clamped during RCP (IVC-clamped group). During RCP, the percent of returned blood volume, oxygen consumption, exudation of carbon-dioxide, and oxygen saturation of the returned blood were significantly higher in the IVC-clamped group than in the IVC-drained group, and the concentration of serum CK-BB in the IVC-clamp group was significantly lower than in the IVC-drained group. However, there was no statistical difference between the two groups concerning the regional cerebral blood flow or water content of the cerebral tissue. Concerning about these results, a part of perfused blood passed through not only the extra cranial veno-venous connection but also the intra cranial veno-capillary-venous connection. We concluded that clamping of the venous blood flow through the IVC cannula during RCP is a more protective procedure for cerebral tissue.

Animals↗
PubMed1996

Autoregulation of renal and splanchnic blood flow following infra-renal aortic clamping is mediated by nitric oxide and vasodilator prostanoids.

OBJECTIVE: This study examines the hypothesis that nitric oxide and vasodilator prostanoids contribute to the autoregulation of renal artery and superior mesenteric artery (SMA) blood flow following infra-renal aortic clamping. EXPERIMENTAL DESIGN: Renal and SMA artery blood flow were measured in anesthetized rats. The rats received bolus injection of saline carrier, L-NAME (25 mg/kg) or indomethacin (15 mg/kg) prior to sham or infra-renal aortic occlusion. In vivo blood flow was measured 1, 30 and 60 minutes during aortic occlusion and 1, 30, and 60 minutes following release of the aortic cross clamp. RESULTS: Aortic occlusion transiently increased SMA blood flow but did not alter renal artery blood flow. Aortic clamp release resulted in a 40% decrease in both SMA and renal artery blood flow. L-NAME or indomethacin pretreatment decreased both SMA and renal artery blood flow at 60 minutes following infrarenal aortic occlusion. Indomethacin decreased SMA blood flow at 1 minute following unclamping of the aorta and L-NAME decreased SMA blood flow at 30 and 60 minutes following aortic clamp release. Both L-NAME and indomethacin markedly decreased renal artery blood flow at all time periods following aortic clamp release. CONCLUSIONS: These data suggest that renal and splanchnic vascular beds utilize endogenous vasodilator eicosanoids and nitric oxide to maintain blood flow during cross clamping and unclamping of the infra-renal aorta.

Animals↗
PubMed1996

Use of the Mogen clamp for neonatal circumcision.

Most newborn circumcisions performed in the United States are done with either a Gomco clamp or a Plastibell device. The Mogen clamp, devised by a jewish mohel, provides a quick and simple surgical alternative. The foreskin is freed from the glans by blunt dissection, but no dorsal slit is made. A dorsal hemostat is placed, and traction is applied to bring the foreskin forward. Placement of the Mogen clamp follows the angle of the corona to avoid removing excess skin ventrally and to obtain a superior cosmetic result. The clamp crushes the foreskin along a line that is 1 mm wide, and the foreskin is excised distal to the clamp. After removal of the clamp, the glans is liberated by pulling the crush line apart. The procedure usually takes three to four minutes and is virtually bloodless.

Circumcision, Male↗
PubMed1996

Protection by coenzyme Q10 of tissue reperfusion injury during abdominal aortic cross-clamping.

PURPOSE: To evaluate the effect of coenzyme Q10 in reducing the skeletal muscle reperfusion injury following clamping and declamping the abdominal aorta. METHODS: 30 patients undergoing elective vascular surgery for abdominal aortic aneurysm or obstructive aorto-iliac disease were randomly divided into two groups: patients in group I were treated with coenzyme Q10 (150 mg/day) for seven days before operation, and those in group II received a placebo. We studied the hemodynamic profile in each patient during clamping and declamping of the abdominal aorta. The plasma concentrations of thiobarbituric acid reactive substances (malondialdhehyde), conjugated dienes, creatine kinase and lactate dehydrogenase were measured in samples from both arterial and inferior vena cava sites. Serial sampling was performed after induction of anesthesia, 5 and 30 minutes after abdominal aortic cross clamping, 5 and 30 minutes after aortic cross-clamp removal. RESULTS: The concentrations of malondialdehyde, conjugated dienes, creatine kinase and lactate dehydrogenase in patients who received CoQ10 were significantly lower than in the placebo group. Decrease of plasma malondialdehyde concentrations correlated positively (p < 0.01) with decrease of both creatine kinase and lactate dehydrogenase release in samples from the inferior vena cava. The hemodynamic profile during clamping and declamping the abdominal aorta was similar in both groups. CONCLUSIONS: Our findings suggest that pre-treatment with coenzyme Q10 may play a protective role during routine vascular procedures requiring abdominal aortic cross clamping by attenuating the degree of peroxidative damage.

Aortic Aneurysm, Abdominal↗
PubMed1996

Clinical experience with two types of pelvic C-clamps for unstable pelvic ring injuries.

The emergency stabilization of unstable pelvic injuries, in particular, injuries to the posterior pelvic ring, can be achieved following reduction by application of the pelvic C-clamp. This and other procedures contribute to controlling what is almost always a life-threatening blood loss. The pelvic C-clamp is a temporary measure preceding definitive treatment of the injury. If this procedure is to have an optimal and lasting effect, the clamp must be applied correctly, provide adequate compression and stability, and be easy to handle. In one year, we applied the AO and ACE pelvic clamps in 9 clinical cases. Satisfactory primary compression and stability were achieved for unstable injuries with both clamps. It was more difficult to achieve good rotational stability as required for subsequent treatment with the ACE clamp due to its construction design.

External Fixators↗