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Biomedical subjects

P O Daily

Publications and source records attributed to P O Daily.

At least 37 records · Page 2Linked to original sources
PubMed1992

Long-term results of treatment of Budd-Chiari syndrome with portal decompression.

Thirty-three patients with Budd-Chiari syndrome were studied for 1 to 19 years following portal decompression. All had ascites, hepatomegaly, abnormal liver function, angiographic demonstration of inferior vena cava and/or hepatic vein occlusion, and biopsy specimens showing intense hepatic congestion and necrosis. When thrombosis was confined to hepatic veins (20 patients), side-to-side portacaval shunt resulted in 95% operative survival, 90% prolonged survival, permanent shunt patency, relief of ascites, reversal of liver dysfunction, and reversal or improvement of hepatic lesions. When thrombosis involved the inferior vena cava, mesoatrial shunt (eight patients) was unsatisfactory because of a 63% mortality rate from liver failure due to shunt thrombosis. In contrast, a new procedure consisting of combined portacaval and caval-atrial shunts (five patients) has been highly successful, with 100% survival, shunt patency, relief of ascites, and reversal of pathologic abnormalities.

Adult↗
PubMed1992

Treatment of Budd-Chiari syndrome due to inferior vena cava occlusion by combined portal and vena caval decompression.

This study concerns Budd-Chiari syndrome (BCS) caused by occlusion of the subdiaphragmatic inferior vena cava (IVC). It describes the experimental and clinical evaluation of the treatment of this disorder by one-stage combined portal and vena caval decompression with a direct side-to-side portacaval shunt (PCS) and a caval-atrial shunt (CAS) graft. BCS was produced in rats by gradual occlusion of the suprahepatic IVC with an ameroid constrictor. When ascites and portal hypertension were established, 12 control rats survived a sham thoracolaparotomy, 16 rats survived a mesoatrial shunt, and 16 rats survived combined PCS and CAS graft. All control rats re-formed ascites and died within 2 months. Nine of 16 rats with mesoatrial shunt developed graft thrombosis, re-formed ascites, and died within 2 months. In contrast, only 2 of 16 rats that underwent combined PCS and CAS developed graft thrombosis, re-formed ascites, and died. Liver biopsies showed reversal of severe pathologic changes in rats with patent grafts. Clinical evaluation of combined PCS and CAS using a 20-mm ring-reinforced Gore-Tex graft has been undertaken in five patients with BCS and ascites, hepatosplenomegaly, intense hepatic congestion on biopsy, and angiography showing occlusion of both the IVC and hepatic veins. All five patients are alive and well 6 months to 7.5 years postoperatively with patent grafts, no ascites or need for diuretics, no encephalopathy, normal liver function, and reversal of liver pathology. It is concluded that combined PCS and CAS create a high-flow shunt that decompresses both the portal system and IVC, has a low incidence of graft thrombosis, has been consistently effective in relieving BCS caused by IVC occlusion, and appears to be superior to mesoatrial shunt.

Adult↗
PubMed1991

Dissectors for pulmonary thromboendarterectomy.

Even with circulatory arrest during pulmonary thromboendarterectomy, continued back-bleeding obscures the operative field. This necessitates frequent interruptions of dissection to allow aspiration with a second instrument. Therefore, pulmonary thromboendarterectomy dissectors are described that allow simultaneous suction of blood from the operative field. Before the use of these dissectors, circulatory arrest time was 59 +/- 23 minutes in 124 consecutive patients. In the last 10 consecutive patients using these dissectors, the mean circulatory arrest time has been 52 +/- 22 minutes (p = not significant). It is anticipated that with a larger database, the ability to aspirate blood simultaneously during the dissecting process will result in a significant shortening of circulatory arrest time.

Endarterectomy↗
PubMed1991

Optimizing myocardial hypothermia: I. Temperature probe design and clinical inferences.

Myocardial hypothermia is an essential component of myocardial preservation for most cardiac operations. Because of multiple causes of rewarming, it is necessary to monitor temperatures at specific sites (right and left ventricular epicardium and endocardium or cavity). Thus, plastic temperature probes have been designed and fabricated to facilitate temperature monitoring at these sites. Using a bare thermocouple as a standard, in vitro comparison of metallic probes and plastic probes revealed differences of 4.0 degrees +/- 0.9 degrees C and 0.7 degrees +/- 0.6 degrees C, respectively (p less than 0.005). Consequently, metallic probes do not have sufficient accuracy to detect transmural temperature gradients because of "stem effect." Using the plastic probes to evaluate temperature changes in porcine hearts after cardioplegia-induced hypothermia revealed a temperature rise of 1 degree C/min at all sites if control of systemic and venous return and local myocardial cooling are not provided. The use of temperature monitoring at multiple sites permits identification and prevention of various causes of myocardial rewarming and is facilitated by the use of plastic probes described herein which contain dual thermocouples.

Animals↗
PubMed1991

Optimizing myocardial hypothermia: II. Cooling jacket modifications and clinical results.

After induction of myocardial hypothermia by cold cardioplegic solution, myocardial rewarming occurs at 0.5 degrees to 1.0 degrees C/min. In addition to preventing myocardial rewarming from systemic and pulmonary venous return, continuous cooling of the myocardial surface must be provided. Modifications of a previously reported cooling jacket are described. These modifications include decreased width and thickness of the metal skeleton for easier application and increased malleability, respectively. Also, the double-row flow channel markedly minimizes obstruction of flow secondary to kinking and allows inlet and outlet lines to attach at adjacent points of the jacket thus minimizing obstruction of the operative field. The effectiveness of the jacket in 36 patients undergoing valve replacement and 19 patients having pulmonary thromboendarterectomy was evaluated by measurement of myocardial temperatures at multiple sites throughout aortic cross-clamping. Temperatures at all sites were maintained at 12 degrees C or less. Temperatures measured in phrenic nerve pedicles ranged from 25 degrees to 27 degrees C. During cooling, heat removal by the jacket was 330 calories/min. During maintenance of myocardial hypothermia, heat flow was 190 calories/min. Modifications of a cooling jacket facilitate usability and an array of sizes enhances applicability.

Body Temperature↗
PubMed1991

Epicardial activation and repolarization patterns in patients with right ventricular hypertrophy.

To map global epicardial repolarization patterns and test the "SI" model of T wave generation, the patterns of epicardial activation and repolarization in patients with chronic pulmonary thromboembolism and right ventricular hypertrophy were studied by computerized mapping techniques and monophasic action potential (MAP) recording. The ventricular activation patterns were characterized by delayed right ventricular activation and the absence of normal early epicardial ventricular breakthrough in some cases. The repolarization patterns were characterized by nonuniform distribution of T wave morphologies. The T waves were predominantly positive over the left ventricular epicardium and negative or biphasic over the right ventricular epicardium. The activation-recovery (A-R) intervals were measured from the local activation to the maximal dV/dt of the upstroke of the T waves (Wyatt method). The difference between the A-R intervals and the MAP from onset of activation to 90% repolarization (MAP90) varies according to T wave morphology and could be as high as 96 msec with positive T waves, despite significant correlations (r = 0.56-0.90) between MAP90 and A-R intervals for each morphology. Better overall correlations were found if the minimal dV/dt on the downslope of the positive T waves was chosen to estimate the time of local repolarization (alternative method). Using this method, the mean A-R intervals were the same over the right and left ventricles. Cardiopulmonary bypass significantly prolonged the action potential duration equally at all parts of the epicardium. We conclude that in patients with right ventricular hypertrophy, the time of local repolarization can be estimated by our alternative method; the right ventricle completes activation and repolarization later than the left ventricle, and the distribution of T wave morphologies is nonuniform, with predominantly positive T waves observed over the left ventricle and negative or biphasic T waves observed over the right ventricle. These findings are compatible with the SI model of the generation of T waves.

Action Potentials↗
PubMed1990

Aortic valve repair for aortic stenosis in adults.

The stenotic aortic valve was surgically repaired in 48 adults, 21 women and 27 men, aged 38 to 83 years. Five had congenital aortic stenosis (AS), with a mean aortic valve gradient and area of 58 +/- 23 mm Hg (standard deviation) and 0.54 +/- 0.13 cm2, respectively; 32 had senile AS with a mean aortic valve gradient and area of 43 +/- 20 mm Hg and 0.98 +/- 0.41 cm2; and 11 had rheumatic AS with a mean aortic valve gradient and area of 59 +/- 24 mm Hg and 0.47 +/- 0.15 cm2. Only 6 patients underwent isolated aortic valvoplasty, 11 underwent concomitant mitral valve procedure, and 34 underwent concomitant coronary revascularization. Repair consisted of decalcification in 33 patients and decalcification as well as commissurotomy in 15 patients. There were three hospital deaths, none related to the aortic valve. Only 2 patients (both rheumatic) did not improve clinically. During follow-up (mean, 64 +/- 41 months) aortic valve restenosis developed in 24% (10 patients, 3/5 congenital, 4/11 rheumatic, and 3/32 senile) at a mean of 64 +/- 28 months. Postoperative Doppler echocardiographic assessment of 21 patients with senile AS at 1.1 +/- 2.7 and 18.1 +/- 1.4 months showed significantly lower aortic valve gradient and improved area in comparison with preoperative values. At 36 +/- 2.7 months, aortic valve gradient and area were not significantly different than preoperative values, and at 58.5 +/- 2.6 months aortic valve gradient was 1.41 (p = 0.07) times the preoperative value. At 7 years, actuarial freedom from aortic valve-related symptoms of the patients with senile AS was 87%. We conclude that in select patients aortic valve repair results in excellent relief of AS. Late restenosis is expected and more likely to occur in the valves with congenital and rheumatic disease than in those with senile disease.

Adult↗
PubMed1990

Improved patient survival after cardiac arrest using a cardiopulmonary support system.

A portable cardiopulmonary bypass system that can be rapidly deployed in a nonsurgical setting using nursing staff was used in 38 patients with cardiovascular collapse refractory to ACLS protocol. Percutaneous or cutdown cannulation sites were: femoral vein-femoral artery (n = 18), right internal jugular vein-femoral artery (n = 2), right atrium-ascending aorta (n = 12), or a combination approach (n = 4). Two patients could not be cannulated. Patient diagnoses were pulmonary emboli (n = 3), failed coronary angioplasty (n = 7), myocardial infarction with cardiogenic shock (n = 5), trauma (n = 7), aortic stenosis (n = 2), postcardiotomy deterioration (n = 10), deterioration after cardiac transplantation (n = 2), cardiomyopathy with shock (n = 1), and ruptured ascending aortic dissection (n = 1). Ninety-five percent of patients (36 of 38) were successfully resuscitated to a stable rhythm. Eight diagnostic procedures (coronary angiography, n = 4; pulmonary angiography, n = 3; and aortography, n = 1) were performed while patients were on cardiopulmonary support. Early deaths resulted from massive hemorrhage (n = 8), inability to cannulate (n = 2), and irreversible myocardial injury (n = 10). Sixty-six percent (24 of 36) of patients successfully cannulated underwent conversion to standard cardiopulmonary bypass with attendant operative procedure or placement of ventricular assist device or total artificial heart. Fifty percent (18 of 36) of patients cannulated were successfully weaned from cardiopulmonary support, and 17% (6/36) are long-term survivors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Current early results of pulmonary thromboendarterectomy for chronic pulmonary embolism.

Some patients with chronic pulmonary embolism causing severely symptomatic pulmonary hypertension have been managed by heart-lung transplantation with an associated hospital mortality of 24%. To allow comparison with pulmonary thromboendarterectomy (PTE), we have reviewed the hospital morbidity and mortality in 149 consecutive patients. From 1 October 1984 to 18 September 1989, these patients underwent PTE utilizing a standardized procedure consisting of median sternotomy, cardiopulmonary bypass, deep hypothermia and circulatory arrest for bilateral PTE in 91% (136/149) of the procedures with 7.4% (11/149) and 1.3% (2/149) undergoing right or left PTE, respectively. Ventilator dependency (greater than or equal to 5 days on respirator) occurred in 28.3% (41/146). Hospital mortality (death within 30 days or in hospital) was 11.4% (17/149). The most common causes of death were respiratory and multiorgan failure, 10 (59% of deaths) and acute pulmonary hemorrhage, 3 (17% of deaths). We conclude that PTE with an operative mortality of half that of heart-lung transplantation (11.4% vs. 24%) should be the procedure of choice for significantly symptomatic chronic pulmonary embolism. Furthermore, the hazards of immunosuppression and chronic graft rejection are avoided.

Adult↗
PubMed1990

Importance of acid-base strategy in reducing myocardial and whole body oxygen consumption during perfusion hypothermia.

During induced hypothermia with cardiopulmonary bypass, acid-base management usually follows one of two strategies: the so-called ectothermic or alpha-stat strategy, in which the pH of the arterial blood increases 0.015 pH units for every degree Celsius decrease in body temperature, or the pH-stat strategy, in which pH remains 7.4 at all temperatures. It has been assumed that oxygen consumption decreases approximately equally during hypothermia with either strategy, although there are biochemical reasons to hypothesize that oxygen consumption would be better maintained with the alpha-stat strategy. We also hypothesized that venous oxygen tension would be lower with the more alkaline alpha-stat strategy than with the pH-stat acid-base strategy, because of the Bohr effect. We tested these hypotheses by placing 10 anesthetized immature domestic pigs on cardiopulmonary bypass. We measured whole body oxygen consumption and myocardial oxygen consumption. Control measurements were made at 37 degrees C. Then the animals were cooled to 27 degrees C and the measurements were repeated. The alpha-stat strategy (pH 7.554 +/- 0.020 at 27 degrees C) was used in five animals and five animals received pH-stat management (pH 7.409 +/- 0.012 at 27 degrees C). Whole body and myocardial oxygen consumption rate decreased in both groups, but more so in the alpha-stat animals than in the pH-stat animals. The unexpectedly high oxygen consumption in the pH-stat animals also resulted in a lower than expected venous oxygen tension. Thus the effect of hypothermia in reducing oxygen consumption was less pronounced with pH-stat acid-base management.

Acid-Base Equilibrium↗
PubMed1990

Risk factors for pulmonary thromboendarterectomy.

Pulmonary thromboendarterectomy is being performed with increasing frequency for incapacitating pulmonary hypertension caused by chronic large-vessel pulmonary embolism. However, patient-related risk factors and procedural complications associated with morbidity and mortality have not been fully defined. From Oct. 1, 1984, to April 10, 1989, we performed pulmonary thromboendarterectomy using deep hypothermia and circulatory arrest in 127 consecutive patients (62.2% male, mean age 50 +/- 16 [standard deviation], range 20 to 82 years) in whom the exposure and dissection of the pulmonary arteries and methods for myocardial protection have been standardized. End points for univariate and multivariate analyses of risk factors were reperfusion pulmonary edema leading to respiratory insufficiency as defined by ventilator dependency (greater than or equal to 5 days) (31.5%, 39/124) and hospital mortality (12.6%, 16/127). Multivariate analyses showed that ascites and need for 4 units of blood or more predicted ventilator dependency (p less than 0.03). Increased cardiopulmonary bypass times predicted both end points (p less than 0.03 to less than 0.0001), and failure to achieve at least a 50% reduction in pulmonary vascular resistance strongly predicted hospital death (p less than 0.0001). However, other factors that exhibited trends for association with one of the end points may prove important with a larger sample size. A hospital mortality rate of 12.6% for pulmonary thromboendarterectomy is acceptable when compared with approximately 25% for heart-lung transplantation, which is the only therapeutic alternative. Increased ventilator dependency and hospital mortality can be anticipated with longer cardiopulmonary bypass times and inadequate reduction of pulmonary vascular resistance.

Adult↗
PubMed1989

Apparent coagulopathy caused by infusion of shed mediastinal blood and its prevention by washing of the infusate.

We found that reinfusion of shed mediastinal blood (SMB) after a cardiac operation was associated with laboratory evidence of disseminated intravascular coagulation. In view of this, we compared the effect of infusing washed or unwashed SMB on the coagulation profiles and blood use of two serial groups of patients undergoing cardiopulmonary bypass. We found that the results of testing for fibrin degradation products converted from negative to positive in 17 of 20 patients who received unwashed SMB versus 1 of 14 patients who received washed SMB (p less than 0.0001). Other coagulation studies did not reveal disseminated intravascular coagulation in either group, nor were there differences in blood use between the two groups. The unwashed SMB contained high titers of fibrin degradation products (mean reciprocal titer = 354 +/- 161) compared with washed SMB (mean reciprocal titer = 34 +/- 18) (p less than 0.01). Based on the volume of SMB infused, the amount of fibrin degradation products in unwashed SMB was sufficient to account for the positive fibrin degradation product assays after infusion in this group. We conclude that infusion of unwashed SMB may confuse the interpretation of tests for disseminated intravascular coagulation or fibrinolysis. As this could lead to unnecessary blood component use and is preventable by washing before infusion, we recommend that the routine infusion of unwashed SMB no longer be employed.

Blood Coagulation Tests↗
PubMed1989

Technique of pulmonary thromboendarterectomy for chronic pulmonary embolism.

Pulmonary embolism infrequently results in severe chronic pulmonary arterial obstruction. However, when it does, affected patients are significantly symptomatic and have shortened survival. Medical management has proven ineffective. In the majority of surgical reports, unilateral thoracotomy with distal pulmonary arteriotomies has been emphasized. The average operative mortality was 22%. In this article, we discuss various preoperative considerations and describe in detail a surgical approach using median sternotomy for bilateral pulmonary thromboendarterectomy with cardiopulmonary bypass, deep hypothermia and circulatory arrest. With this standardized approach in 103 consecutive patients from October 1, 1984, to September 20, 1988, the hospital mortality (death within 30 days or during hospitalization) has been 11.7%.

Cardiopulmonary Bypass↗
PubMed1989

Chronic thromboembolic occlusion in the adult can mimic pulmonary artery agenesis.

In the first 100 patients operated on for C T-E PH, three were referred with the diagnosis of UPAA having been made elsewhere. We found that many features of these two conditions are so similar that differential diagnosis is very difficult. Shared features may include findings on chest x-ray film, pulmonary angiography, CT scan and MRI studies. Since the two conditions vary substantially with respect to the methods of potential surgical correction, recognition of this possible differential diagnostic dilemma is important.

Adult↗
PubMed1989

Early and five-year results for coronary artery bypass grafting. A benchmark for percutaneous transluminal coronary angioplasty.

Patients currently undergoing coronary artery bypass grafting will likely have worse early and late results because of the selection of patients with fewer risk factors for percutaneous transluminal coronary angioplasty. Therefore, until the results of randomized prospective studies are available, angioplasty should also be compared to bypass grafting before the era of angioplasty to facilitate current comparison with bypass grafting. To obtain these data, I analyzed 500 consecutive patients (aged 33 to 79 years [58 +/- 10 SD], 20% [100/500] female, and 60% [300/500] with three vessel disease) undergoing first-time coronary bypass without associated procedures between late 1976 and mid-1980. Intermittent aortic cross-clamping (for each distal graft) was used for revascularization of all arteries 1.0 mm in internal diameter or larger with stenoses of 50% or greater. This strategy resulted in complete revascularization in 99.8% of patients, averaging 3.2 +/- 1.2 distal grafts per patient. The hospital mortality rate was 0.2% (1/500). The incidence of low output syndrome necessitating pressors (0.8%) or intraaortic balloon pump support (0.2%) was 1% (5/500). Perioperative myocardial infarction rate based on new Q waves was 2.2% (11/500). All but three patients (99.4%) were contacted at 5 years or later with respect to repeat coronary bypass or angioplasty and survival. The survival rate at 5 years, including hospital deaths, was 92.7% +/- 1.2% (70% confidence limits) for cardiac deaths, 89.8% +/- 1.4% for all deaths, and 89.8% +/- 1.4% for all deaths plus three patients lost to follow-up. Approximately 40 factors were screened univariately to determine their effect on survival and survival free from repeat intervention. Multivariate analysis revealed, as in other series, that decreased left ventricular function (ejection fraction less than 50%) was the predominant determinant of decreased 5-year survival for both cardiac death and total mortality. At 5 years, the freedom from reintervention was 97.7% +/- 0.7%. Factors associated with repeat intervention were younger age (52 +/- 11 years versus 58 +/- 10, p less than 0.05) and fewer grafts (2.3 +/- 1.0 versus 3.3 +/- 1.2, p less than 0.01) because of less severe disease (three vessel disease 31% versus 60%, p less than 0.05). These results provide a benchmark for angioplasty which should attain a hospital mortality rate of under 1%, a periprocedure myocardial infarction rate under 3%, and a 5-year survival rate of approximately 90% with more than 95% of survivors free of repeat intervention in unselected patients, not cohorts with primarily single vessel disease.

Adult↗