Biomedical subjects

L H Blackbourne

Publications and source records attributed to L H Blackbourne.

16 recordsLinked to original sources

PubMed2006

Is there an optimal time for laparoscopic cholecystectomy in acute cholecystitis?

BACKGROUND: Laparoscopic cholecystectomy (LC) is safe in acute cholecystitis, but the exact timing remains ill-defined. This study evaluated the effect of timing of LC in patients with acute cholecystitis. METHODS: Prospective data from the hospital registry were reviewed. All patients admitted with acute cholecystitis from June 1994 to January 2004 were included in the cohort. RESULTS: Laparoscopic cholecystectomy was attempted in 1,967 patients during the study period; 80% were women, mean patient age was 44 years (range, 20-73 years). Of the 1,967 LC procedures, 1,675 were successful, and 292 were converted to an open procedure (14%). Mean operating time for LC was 1 h 44 min (SD +/- 50 min), versus 3 h 5 min (SD +/- 79 min) when converted to an open procedure. Average postoperative length of stay was 1.89 days (+/- 2.47 days) for the laparoscopic group and 4.3 days (+/- 2.2 days) for the conversion group. No clinically relevant differences regarding conversion rates, operative times, or postoperative length of stay were found between patients who were operated on within 48 h compared to those patients who were operated on post-admission days 3-7. CONCLUSIONS: The timing of laparoscopic cholecystectomy in patients with acute cholecystitis has no clinically relevant effect on conversion rates, operative times, or length of stay.

Adult↗

PubMed1997

Pancreatic adenocarcinoma in the pregnant patient: case report and review of the literature.

BACKGROUND: In this case report, the authors discuss the presentation and treatment of pancreatic adenocarcinoma in a pregnant woman. Pancreatic adenocarcinoma is extremely rare in the pregnant patient. Only three cases of pancreatic adenocarcinoma diagnosed antepartum have been reported. METHODS: A case report and a review of the literature are reported. RESULTS: The authors report a case of pancreatic adenocarcinoma in a pregnant woman at 17 weeks' gestation. Endoscopic retrograde cholangiopancreatography with stent placement and a pancreaticoduodenectomy were performed successfully. CONCLUSIONS: Pancreatic adenocarcinoma is very rare in the pregnant patient. However, pancreaticoduodenectomy can be performed successfully. To the authors' knowledge, this is the first report of a pregnant woman treated with pancreaticoduodenectomy for pancreatic adenocarcinoma.

Adenocarcinoma↗

PubMed1995

Prevention of spinal cord injury after repair of the thoracic or thoracoabdominal aorta.

Spinal cord injury occurring as the result of surgical repair of thoracic and thoracoabdominal aortic disease remains a devastating complication. The incidence of postoperative neurologic deficits varies from 4% to 38%. Factors associated with a greater risk for injury include the presence of dissection or extensive thoracoabdominal disease, and a prolonged cross-clamp time. Spinal cord ischemia initiates a deleterious cascade of biochemical events that ultimately result in an increased intracellular calcium concentration. Calcium-activated proteases, lipases, and nucleases mediate the processes that cause cell injury. The accumulation of oxygen-derived free radicals and the occurrence of hyperemia during reperfusion are also contributing causes of spinal cord injury. Increasing the spinal cord blood flow with shunts, oxygenated bypass circuits, cerebrospinal fluid drainage, the intrathecal administration of vasodilators, and the reattachment of intercostal arteries has been tried in an effort to increase spinal cord perfusion. Pharmacologically based measures to prevent spinal cord injury have been pursued, and these have consisted of hypothermia, anesthetic agents, calcium channel blockers, free radical scavengers, and immune system modulation. However, no single technique has proved to be consistently effective in preventing ischemia-induced spinal cord injury.

Aorta↗

PubMed1995

Compensatory growth of porcine right lungs after chronic rejection of transplanted left lungs.

Neonatal lung hypoplasia is frequently a fatal condition often associated with congenital diaphragmatic hernia. Unilateral lung transplantation rarely has been performed for this indication, although it is a potential solution. It is not known whether the transplant needs to function permanently or to act as a bridge until the native lung develops. It is also not known whether the native lung will grow in the face of an immunosuppressed state and chronic rejection of the transplanted lung. We therefore developed a porcine model of left lung rejection to study this. Infant swine underwent left lung transplantation. Chronic rejection occurred in all, resulting in nonfunction of the transplanted lung. The right lungs of these animals were compared with the right lungs of size-matched and age-matched control animals not given immunosuppressive treatment and not undergoing transplantation. There were no differences in terms of the functional residual capacity, airway compliance, and airway resistance among the groups. There was a significant increase in the pulmonary vascular resistance in the animals with transplanted lungs. There was also a significant increase in the lung weight in these animals. Unilateral pneumonectomies were done in 4 infant pigs to serve as controls. Three of the 4 did not survive the operation because of acute pulmonary failure. In conclusion, the study group exhibited evidence of compensatory growth that was not seen in the control animals, as shown by the increase in lung weight. This suggests that contralateral lung growth occurs in a growing animal, despite the effects of immunosuppression therapy and chronic rejection of the transplanted lung.

Animals↗

PubMed1995

Predicting survival after coronary revascularization for ischemic cardiomyopathy.

BACKGROUND: The success of coronary revascularization for ischemic cardiomyopathy (left ventricular ejection fraction of 0.25 or less) has been unpredictable. We and others have demonstrated that the hospital operative mortality rate for these operations has been surprisingly low, particularly if evidence of ischemia is present. We subsequently liberalized our selection criteria based on our hypothesis that coronary artery bypass grafting is safe in this subset of patients regardless of the status of their distal coronary vasculature. METHODS: To examine this hypothesis, we studied retrospectively our patients undergoing coronary artery bypass grafting from 1983 to 1993. Ninety-six patients with ejection fractions of 0.25 or lower underwent this operation, with 88 hospital survivors (mortality 8%). All of the patients had clinical symptoms of heart failure. The male to female ratio was 4.6:1. The average age was 63.1 +/- 0.9 years (mean +/- standard error of the mean). Patients were excluded if they had valvular heart disease other than mild to moderate mitral regurgitation, required resection of a ventricular aneurysm, or required an emergency operation for acute coronary occlusion. Possible predictors of death were examined retrospectively. The catheterization films were reviewed retrospectively by a cardiovascular surgeon who was blinded to patient outcome and was never involved in the clinical management of any of the patients. Vessel quality was described as good, fair, or poor. RESULTS: Increased age and poor vessel quality were the only significant predictors of poor outcome. Sex, presence or absence of angina, preoperative angina, preoperative ejection fraction, preoperative arrhythmia disorder, aortic cross-clamp time, and the number of bypass grafts had no significant effect on outcome in the perioperative period. CONCLUSION: These results demonstrate that poor vessel quality and older age are predictors of poor outcome in patients with low ejection fractions undergoing myocardial revascularization. We conclude that poor distal coronary vasculature is a contraindication to coronary artery bypass grafting in patients with an ejection fraction of 0.25 or less, even if angina is present.

Age Factors↗

PubMed1994

Successful use of undersized donors for orthotopic heart transplantation--with a caveat.

Accepted clinical practice has been to require body weights to be within 20% as a criterion for matching donor to recipient for cardiac transplantation. From November 1989 through September 1993 we began accepting larger differences in body weight between donor and recipient with 80 orthotopic heart transplants performed. Twenty-eight of these transplants used undersized donors (donor-to-recipient body weight ratio [DRBW] of 0.6 to 0.8) with the remaining donors being either size matched (DRBW = 0.8 to 1.0) or oversized (DRBW > 1.0). Thirty-three of the 80 transplant recipients (41%) were classified preoperatively as United Network for Organ Sharing (UNOS) status I and the remaining patients were classified as UNOS status II. Hospital survival for status I recipients was 9 of 14 (64%) for undersized donors, 7 of 8 (87.5%) for sized-matched donors, and 11 of 11 (100%) for oversized donors (p < 0.05). Hospital survival for status II recipients was 12 of 14 (85.7%) for undersized donors, 24 of 24 (100%) for sized-matched donors, and 8 of 9 (88.8%) for oversized donors. Our data support the continued use of hearts from undersized donors in status II recipients. The use of hearts from undersized donors in status I recipients is associated with increased mortality compared with size-matched donors and must be undertaken with caution.

Adult↗

PubMed1994

Ambulatory intraaortic balloon counterpulsation.

A technique is described for the retroperitoneal placement of a balloon pump that preserves patient mobility. This technique may be superior to standard femoral placement when prolonged support is required for cardiac transplant candidates awaiting donor organs.

Ambulatory Care↗

PubMed1994

Management of renal tumors involving the inferior vena cava.

PURPOSE: We reviewed our experience of the resection of renal tumors involving the inferior vena cava (IVC) from 1987 to 1992 with the hypothesis that retrohepatic IVC involvement of renal tumors can be managed without cardiopulmonary bypass (CPB) and circulatory arrest with acceptable morbidity and mortality rates. METHODS: We retrospectively reviewed our experience of radical nephrectomies for renal tumors from 1987 to 1992 (n = 69). Of these, 13 had involvement of the IVC (19%). Three of the patients had right atrial extension requiring CPB with circulatory arrest. Three patients had retrohepatic involvement, and seven had infrahepatic involvement. All thirteen patients underwent operative removal of the tumor and tumor thrombus. RESULTS: The patients with atrial extension who were treated with CPB and circulatory arrest had hospital and 1-year survival rates of 100% (three of three). The patients with retrohepatic extension treated without CPB and circulatory arrest had hospital and 1-year survival rates of 100% (three of three). The patients with infrahepatic extension treated without CPB and circulatory arrest had hospital and 1-year survival rates of 85% (six of seven) and 50% (three of six), respectively. There was no statistically significant difference between groups. The hospital death occurred in a patient who had a massive pulmonary embolism and disseminated intravascular coagulation before operation. The deaths that occurred before 1 year were due to metastatic disease and unresectable disease at the time of operation. CONCLUSION: CPB with circulatory arrest is not required in patients with retrohepatic IVC extension of renal tumors, and aggressive resection can be performed in these patients with acceptable morbidity and mortality rates.

Blood Loss, Surgical↗

PubMed1994

Optimal timing of abdominal aortic aneurysm repair after coronary artery revascularization.

OBJECTIVE: The authors ascertained the optimal timing of repair of an abdominal aortic aneurysm (AAA) after coronary artery revascularization. SUMMARY BACKGROUND DATA: Cardiac events are the most common cause of death after elective repair of AAA. Preoperative coronary revascularization has significantly reduced postoperative cardiac complications after elective AAA repair. Currently, most patients undergo repair of asymptomatic AAA within 6 months after the coronary revascularization. METHODS: The authors performed a retrospective review of patients who underwent repair or scheduled repair of an asymptomatic AAA within 6 months after coronary artery bypass graft (CABG) between March 1988 and October 1993. RESULTS: There was no mortality in the group of patients (n = 14) who underwent repair of AAA simultaneously or within 14 days of coronary revascularization. In contrast, there was a significantly increased mortality rate of 3 of 9 (33%) in patients scheduled to undergo repair of the AAA more than 2 weeks after coronary revascularization (p < 0.05). All nonsurvivors died between 16 and 29 days after CABG, and died as a result of ruptured AAA. CONCLUSION: Elective AAA repair should be undertaken simultaneously or within 2 weeks of coronary artery revascularization because of an increased risk of postoperative AAA rupture seen after this time period. In addition, simultaneous or early postoperative AAA repair does not increase the overall operative risk.

Aged↗

PubMed1994

The sensitivity and role of ultrasound in the evaluation of biliary obstruction.

Ultrasound is widely advocated as the initial noninvasive imaging study in evaluating suspected biliary obstruction. Some have suggested using ultrasound as the sole diagnostic test before exploratory laparotomy. To evaluate the accuracy of ultrasound in determining the level and etiology of biliary obstruction in patients with biliary dilatation, and to define its role in the evaluation of these patients, we performed a retrospective review of all patients from August 1986 to August 1991 who had biliary dilatation by ultrasound and subsequent endoscopic retrograde cholangiopancreatography and/or a percutaneous transhepatic cholangiography. Forty-two patients were included in this study, and ultrasound delineated the level of obstruction in 88 per cent, defined the etiology of the obstruction in 48 per cent, and diagnosed choledocholithiasis in 33 per cent of patients with this condition. A literature review revealed that ultrasound has a sensitivity of 71 per cent in delineating the level of obstruction, a sensitivity of 57 per cent in defining the etiology of biliary obstruction, and detects choledocholithiasis in 32 per cent of patients with this condition. We conclude that ultrasound is a highly accurate diagnostic test for delineating the level of biliary obstruction. Ultrasound should be the initial radiographic test in the evaluation of the patient with suspected biliary obstruction to guide further radiographic evaluation.

Aged↗

PubMed1994

Complete prevention of postischemic spinal cord injury by means of regional infusion with hypothermic saline and adenosine.

Spinal cord injury after operations on the descending thoracic and thoracoabdominal aorta remains a persistent clinical problem. Previous attempts to decrease the risk of this devastating complication by lowering the rate of metabolism of the spinal cord have met with varying success. We hypothesized that the tolerance of the spinal cord to an ischemic insult could be improved by means of adenosine. Twenty New Zealand white rabbits underwent 40 minutes of isolated infrarenal aortic occlusion after heparin anticoagulation. Clamps were placed both below the left renal vein and above the aortic bifurcation. In 10 rabbits (group A), a bolus of adenosine (100 mg) was infused into the isolated aortic segment immediately after crossclamping and this bolus was followed by a flush of hypothermic saline (8 degrees C, 30 ml/kg) over the first 10 minutes of ischemia. In one control group of five animals (group B), the descending infrarenal aorta was crossclamped without infusion of adenosine or saline. In another control group of five animals (group C), the aortic segment was flushed with normothermic saline (37 degrees C) in a fashion identical to that of the study group. The aortic clamps were removed after 40 minutes, the abdomen was closed, and the animals were allowed to recover from anesthesia. Spinal cord function was assessed 12, 24, 48, 72, and 96 hours after operation by the Tarlov scale. All animals were put to death at 96 hours after operation and spinal cords were harvested for histologic analysis. The spinal cord function of all group A animals was fully intact with Tarlov scores of 5; group B and group C animals were all paraplegic with Tarlov scores of 0 (p < 0.001, general linear models analysis of variance). Histologic examination of spinal cords from group A rabbits revealed no evidence of cord injury, whereas spinal cords from groups B and C had evidence of extensive cord injury with central gray necrosis, axonal swelling, dissolution of Nissl substance, and astrocyte and macrophage infiltration. Regional infusion of the crossclamped infrarenal rabbit aorta with hypothermic saline and adenosine completely prevented paraplegia in our model despite a 40-minute ischemic insult.

Adenosine↗

PubMed1993

Successful transplantation of marginally acceptable thoracic organs.

OBJECTIVE: This study evaluates the efficacy of personally inspecting marginal thoracic organ donors to expand the donor pool. SUMMARY BACKGROUND DATA: The present donor criteria for heart and lung transplantation are very strict and result in exclusion of many potential thoracic organ donors. Due to a limited donor pool, 20-30% of patients die waiting for transplantation. METHODS: The authors have performed a prospective study of personally inspecting marginal donor organs that previously would have been rejected by standard donor criteria. RESULTS: Fourteen marginal hearts and eleven marginal lungs were inspected. All 14 marginal hearts and 10 of the marginal lungs were transplanted. All cardiac transplant patients did well. The mean ejection fraction of the donor hearts preoperatively was 39 +/- 11% (range 15-50%). Postoperatively, the ejection fraction of the donor hearts improved significantly to 55 +/- 3% (p < 0.002). Nine of the ten lung transplant patients did well and were operative survivors. Our donor pool expanded by 36% over the study period. CONCLUSIONS: The present donor criteria for heart and lung transplantation are too strict. Personal inspection of marginal thoracic donor organs will help to maximize donor utilization.

Heart↗

PubMed1991

Reducing postischemic paraplegia using conjugated superoxide dismutase.

Paraplegia after thoracic aortic aneurysm repair has an incidence of 2.2% to 24%. Oxygen-derived free radicals after reperfusion of an ischemic spinal cord may be partly responsible for neuronal destruction. We studied the effects of polyethylene glycol-conjugated superoxide dismutase (PEG-SOD), a free radical scavenger, as a way of increasing spinal cord tolerance to ischemia. Thirty rabbits underwent 40 minutes of aortic occlusion (a known model of paraplegia). Ten of these animals received 25,000 U/kg of PEG-SOD 24 hours before aortic occlusion and two additional doses of 10,000 U/kg, one before and one subsequent to spinal ischemia. Ten animals received superoxide dismutase in the same dosages as those receiving PEG-SOD. Ten control animals received placebo. All animals were studied for 96 hours, at which time a final neurological examination was performed and the results were recorded. Of the 10 animals treated with PEG-SOD, 2 were completely paralyzed whereas 8 had less (7) or no (1) neurological impairment. Eight of the 10 control animals and 9 of the 10 animals receiving superoxide dismutase were completely paralyzed. None of the control animals or animals receiving superoxide dismutase had a normal neurological examination (p less than or equal to 0.05). Treatment with PEG-SOD before and during occlusion increased the rabbit spinal cord tolerance to a 40-minute ischemic insult. Scavenging free radicals may lessen experimental spinal cord injury.

Animals↗

PubMed1990

Incidence and risk of reintervention after coarctation repair.

We examined the need for intervention after coarctation repair in a retrospective study of 197 procedures performed between 1967 and 1989. Reintervention was required in 23 patients. No technique of coarctation repair was free from complications. Although there were only two stenoses in the group receiving Dacron patch angioplasty, only seven of these procedures were performed in children under the age of 1 year. The risk of stenosis was inversely correlated to the age at primary repair, with children less than 1 year old being at greater risk than those more than 1 year of age (p less than 0.05). Subclavian flap angioplasty had a lower risk of reoperation than end-to-end anastomosis (p less than 0.02). Formation of true aneurysms was confined to the Dacron patch angioplasty group. The morbidity and mortality for reintervention was low in all groups, with only one procedure-related death and no incidence of paraplegia. Although no technique is free from risk, subclavian flap angioplasty leads to fewer reinterventions in younger patients.

Adolescent↗

PubMed1990

Operative risks of the implantable defibrillator versus endocardial resection.

Both map-guided endocardial resection (ER) and the automatic implantable cardioverter defibrillator (AICD) are currently used for surgical treatment of patients who have sustained ventricular tachyarrhythmias. Some authors have preferred AICD implant due to a lower published operative mortality rate. To determine if there is a discrepancy in mortality rates between the two techniques, we analyzed hospital survival in 46 patients undergoing ER and in 44 patients undergoing AICD implantation during the same 3-year period. Two ER patients (4%) died before hospital discharge. Two patients (4%) died after AICD implantation. At predischarge electrophysiologic study five patients (11%) had inducible ventricular tachycardia and received antiarrhythmic drug therapy after ER. In contrast 35 of 42 patients surviving AICD placement received chronic long-term antiarrhythmic therapy (p less than 0.05 compared to ER). Our experience shows that ER and AICD placement may be carried out with similar procedure-related mortality and morbidity rates. Lower operative risks should not be a reason for choosing the AICD over ER for surgical treatment of ventricular tachyarrhythmias. The AICD may actually improve the results of ER by offering an alternative to ventriculotomy in poor-risk surgical candidates.

Aged↗

PubMed1989

Coronary revascularization rather than cardiac transplantation for chronic ischemic cardiomyopathy.

Patients with very poor ventricular function have been thought to be highly vulnerable to elective myocardial revascularization. Ischemic cardiomyopathy is now the major indication for cardiac transplantation. The 2-year survival of medically treated patients with ejection fractions less than 20%, but who are not sufficiently symptomatic for cardiac transplantation, is less than 25%. At our institution we have taken an aggressive approach by using myocardial revascularization for chronic ischemic cardiomyopathy. Between 1983 and 1988, 39 patients with preoperative ejection fractions less than 20% underwent coronary artery bypass. Patients were excluded if they had valvular heart disease other than mild to moderate mitral regurgitation, required resection of a left ventricular aneurysm, or required emergency operation for acute coronary occlusion. Mean age was 63.3 years (range, 43 to 80 years) and 31 were men. Mean preoperative ejection fraction was 18.3% (range, 10% to 20%) and the mean preoperative left ventricular end diastolic pressure was 22 mm Hg (range, 8 mm Hg to 38 mm Hg). There was one operative death (2.6%). Mean follow-up was 21 months (range, 3 to 60 months) with eight late deaths (a total mortality rate of 21%). Seven deaths were due to arrhythmias. Three patients continued to have severe heart failure, one of whom underwent successful cardiac transplantation. By life table analysis, there was a 3-year survival rate of 83%. With the present shortage of cardiac transplant donors, myocardial revascularization for ischemic cardiomyopathy is a reasonably effective means for preserving residual ventricular function.

Adult↗