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Biomedical subjects

D M Bethencourt

Publications and source records attributed to D M Bethencourt.

6 recordsLinked to original sources
PubMed1997

Local transverse arch repair for type A aortic dissection.

BACKGROUND: The management of retrograde dissections originating from the transverse arch is controversial. Although replacing the ascending aorta is clearly beneficial, the appropriate approach to the management of the arch tear is not as apparent and ranges from no intervention to total arch replacement. METHODS: Three patients presented with acute (n = 2) or subacute (n = 1) aortic dissection, with tears involving the transverse arch. All underwent local transaortic pledgeted suture repair of the arch tears during hypothermic circulatory arrest, as well as graft replacement of the ascending aorta. RESULTS: Circulatory arrest times ranged from 12 to 15 minutes (transaortic arch repairs alone) to 48 minutes (transaortic arch repair and open distal graft anastomosis). Postoperatively all patients awoke within 12 hours and subsequently did well neurologically. CONCLUSIONS: In the face of a type A dissection with an entry in the transverse arch, local transaortic repair with concomitant ascending aortic replacement represents a viable middle ground between no arch intervention and lengthy arch replacement. Huge entry tears or aneurysmal arch enlargement would preclude such an approach.

Acute Disease↗
PubMed1993

Neonatal mortality following transfusion of red cells with high plasma potassium levels.

The death of a neonatal infant following cardiac surgery and the transfusion of packed red cells (RBCs) with high plasma potassium levels is reported. The patient had been diagnosed at 2 weeks of age as having multiple cardiac malformations. During cardiopulmonary bypass surgery, multiple units of packed RBCs less than 5 days old were transfused. In response to a "stat" order and after depletion of stock units prepared for neonatal usage, a 32-day-old unit of packed RBCs was issued for transfusion. After approximately 60 mL was rapidly transfused from this unit, the patient experienced cardiac arrest. Serum potassium concentration after transfusion and before death was 8.9 mmol per L. Plasma potassium concentration in the remainder of the transfused packed RBC unit was approximately 60 mmol per L. A model was created to calculate the posttransfusion plasma potassium concentration, and close correlation was found between the model and the observed potassium concentration, which assumes that the potassium load had not yet been distributed to the extravascular and intracellular fluid compartments. It is concluded that the transfusion of relatively large volumes of RBCs be limited to fresh packed RBCs or to packed RBCs that have been saline washed, to minimize the complications of electrolyte disturbances.

Blood Component Transfusion↗
PubMed1988

Muscle-sparing posterolateral thoracotomy.

We have developed a technique for posterolateral thoracotomy that allows adequate exposure for most thoracic operations, yet spares both the latissimus dorsi and serratus anterior muscles. Postoperative pain is decreased, functional recovery is improved, and patients can frequently be discharged earlier from the hospital. Although the time for opening is slightly prolonged, closing time is less and the incision can easily be converted to the standard muscle-splitting approach if more room is required.

Humans↗
PubMed1987

Myocardial protection in the neonatal heart. A comparison of topical hypothermia and crystalloid and blood cardioplegic solutions.

UNLABELLED: Myocardial protection achieved during 2 hours of ischemic arrest was evaluated in 45 isolated, blood perfused, neonatal (1 to 5 days) piglet hearts. Comparisons were made among five methods of myocardial protection: Group I, topical cooling; Group II, hyperosmolar (450 mOsm) low-calcium (0.5 mmol/L) crystalloid cardioplegia; Group III, St. Thomas' Hospital cardioplegia; Group IV, cold blood cardioplegia with potassium (21 mmol/L), citrate-phosphate-dextrose (calcium level 0.6 mmol/L), and tromethamine; and Group V, cold blood cardioplegia with potassium alone (16 mmol/L) (calcium level 1.2 mmol/L). Hemodynamic recovery (percent of the preischemic stroke work) after 30 and 60 minutes of reperfusion was 82.9% and 86.7% in Group I, 35.7% (p less than 0.0001) and 43.7% (p less than 0.0001) in Group II, 76.1% and 77.7% in Group III, 67.4% (p less than 0.05) and 60.6% (p less than 0.05) in Group IV, and 110.7% and 100.6% in Group V. CONCLUSIONS: Topical cooling is an effective method of myocardial protection in the neonate. Cold blood cardioplegia with potassium alone and a normal calcium level provides optimal functional recovery. The improved protection obtained with both crystalloid and blood cardioplegia with normal calcium levels suggests an increased sensitivity of the neonatal heart to the calcium level of the cardioplegic solution.

Animals↗
PubMed1981

Importance of edema and compliance changes during 24 hours of preservation of the dog heart.

The development of myocardial edema and the changes in compliance during long-term preservation and reperfusion of 10 dog hearts were studied. Krebs solution, modified by the addition of potassium chloride (20 mEq/L), was used for 24 hours of low-pressure perfusion (15 mm Hg), at 4 degrees C. The hearts then were reperfused with the use of a support dog. Gravimetric heart water of myocardial biopsy tissue increased from control values of 78.0 +/- 0.8 to 82.8 +/- 0.6 ml/100 gm at 1 hour (p less than 0.01) and to 84.2 +/- 0.3 ml/100 gm after 24 hours of preservation (p less than 0.05 compared to 1 hour). After reperfusion, heart water decreased to 82.8 +/- 0.3 ml/100 gm (p less than 0.05). Passive compliance during preservation, obtained using an inflatable intraventricular balloon, decreased from 1.49 +/- 0.03 ml/mm Hg at 1 hour to 0.65 +/- 0.14 ml/mm Hg at 24 hours (p less than 0.05). High-energy phosphate levels were unchanged at 1 and 24 hours of preservation. Light and electron microscopy at 24 hours of preservation showed marked pericapillary edema and excellent preservation of intracellular structures. During reperfusion, ventricular function curves and dp/dt (2,841 +/- 581 mm Hg/sec) were comparable to previously reported control values. Passive compliance at 24 hours correlated with the diastolic compliance during reperfusion (p less than 0.01). The change in passive compliance during preservation also correlated with the change in coronary vascular resistance, a previously reported index of myocardial viability (p less than 0.05). This study has shown that the change in passive compliance of the heart during perfusion correlates with the adequacy of myocardial preservation and provides an additional index of preserved heart viability.

Adenine Nucleotides↗