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Biomedical subjects

R D Jaquiss

Publications and source records attributed to R D Jaquiss.

10 recordsLinked to original sources

The virtual crossmatch--a screening tool for sensitized pediatric heart transplant recipients.

Heart transplantation in the setting of human leukocyte antigen (HLA) sensitization is challenging, as a time-consuming prospective crossmatch (XM) may be required, severely limiting the number of potential donors. We evaluated a 'virtual XM', defining a positive virtual XM as the presence of recipient pre-formed anti-HLA antibodies to the prospective donor HLA type, and compared the virtual XM to a standard direct XM. Bead-based flow cytometric analysis was used to identify anti-HLA antibody (Ab) present in a child listed for heart transplantation. Using recipient serum, direct-flow cytometric T- and B-cell XM were run for potential donors against whose HLA type the recipient had specific antibodies (group 1, n = 7) and for potential donors with predicted compatible HLA types by virtual XM (group 2, n = 7). Results were expressed as median channel difference (MCD) between the control and recipient serum. A positive T-cell XM was defined as MCD > 50, whereas MCD > 100 constituted a positive B-cell result. The rate of T-cell reactivity was significantly less in group 2 than in group 1 (29% vs. 100%, p = 0.02); similarly, B-cell reactivity was also less for group 2 (14% vs. 100%, p = 0.005). The virtual XM was 100% sensitive in detecting positive flow cytometric XM results for T and B cells. Although only 72% specific in predicting a negative T-cell XM, and 86% specific for negative B-cell XM, the false negatives were weakly positive and would probably have been clinically acceptable. Currently, potentially suitable donor organs are often declined for lack of a prospective XM; these organs may ultimately be allocated to more distant recipients or perhaps not used at all. While further studies are needed, virtual XM has the potential to improve availability of organs for sensitized patients and improve the overall allocation process.

B-Lymphocytes↗

Atrially based pericardial tunnel for central pulmonary artery construction.

Discontinuity of central intrapericardial pulmonary arteries requires reconstruction of a pulmonary artery confluence before cavopulmonary connection, whether this connection be by bidirectional Glenn or Fontan procedure. Reconstruction of the central pulmonary arteries has previously been described using material of poor or no growth potential. A method is described for central pulmonary artery reconstruction that provides growth potential and is based on previous experience with Fontan lateral tunnel construction.

Blood Vessel Prosthesis↗

Repair of long-segment tracheal stenosis in infancy.

Long-segment stenosis of the trachea in infancy is a considerable surgical challenge because the infants are generally extremely ill and the airway is small. The optimal type of repair is not clearly defined. This report summarizes our experience with rib cartilage tracheoplasty done with cardiopulmonary bypass. Six patients underwent repair of long-segment tracheal stenosis between September 1987 and September 1994. The mean age was 14 weeks (range 1 to 58 weeks). Patients had stenosis of at least 70% of the tracheal length, typically with complete cartilaginous rings. In all patients stenosis was repaired by placement of a section of rib cartilage as an augmentation patch into the anterior surface of the trachea, which had been incised through the entire length of the stenosis. To avoid distal airway intubation, we used cardiopulmonary bypass for all procedures, with a mean bypass duration of 110 minutes (range 54 to 175 minutes). Mechanical ventilation was required for a median of 11 days after the operation (range 7 to 81 days), and the median postoperative hospital stay was 17 days (range 12 to 180 days). All patients are long-term survivors. Complications included the need for extracorporeal membrane oxygenation to treat ventricular dysfunction in one patient and graft dehiscence requiring revision of the distal graft in another. The latter patient has required several treatments with a bronchoscope for removal of granulation tissue. All other patients are free of symptoms and have normal growth with a mean follow-up of 4.7 years (range 5 months to 7.6 years). We conclude that rib cartilage tracheoplasty for long-segment tracheal stenosis provides excellent results in short and intermediate follow-up. In addition, the use of cardiopulmonary bypass allows an unobstructed view of the tiny infant airway and thus permits a precise repair.

Cardiopulmonary Bypass↗

Modification of the maze procedure for atrial flutter and atrial fibrillation. I. Rationale and surgical results.

The original maze procedure that was described for the treatment of patients with atrial fibrillation was followed by an unacceptable incidence of two problems: (1) the frequent inability to generate an appropriate sinus tachycardia in response to maximal exercise and (2) occasional left atrial dysfunction. In an effort to overcome these problems, we modified the original technique (maze I) twice. The results of these modifications culminated in the maze III procedure, which is associated with a higher incidence of postoperative sinus rhythm, improved long-term sinus node function, fewer pacemaker requirements, less arrhythmia recurrence, and improved long-term atrial transport function. In addition, the maze III procedure is technically less demanding than either the maze I or maze II procedure. Therefore, the maze III procedure is now the technique of choice for the management of medically refractory atrial fibrillation.

Atrial Fibrillation↗

Physician practices in the treatment of pulmonary embolism and deep venous thrombosis.

To quantify physician practices in the care of patients with presumed pulmonary embolism or deep venous thrombosis, we analyzed heparin sodium orders, the intensity of anticoagulation, and complications in 65 patients with the diagnosis of deep venous thrombosis or pulmonary embolism. All patients were given heparin, for a mean (+/- SEM) period of 8.8 +/- 0.4 days. A high percentage of patients (60%) did not have a single partial thromboplastin time (PTT) greater than 1.5 times control within the first 24 hours of heparin therapy. Not until day 8 were 90% of PTTs in therapeutic range. We identified five common practices that led to delays in achieving a PTT greater than 1.5 times the laboratory control: (1) failure to start heparin therapy at the time of initial clinical suspicion, (2) choice of a heparin sodium bolus (mean, 5861 +/- 365 U) and continuous infusion (1026 +/- 148 U/h) insufficient to elevate the PTT to greater than 1.5 times control, (3) delay in obtaining the first PTT (mean, 11.7 +/- 1 h after start of heparin therapy), (4) insufficient heparin dosing in response to a low PTT, and (5) excessive and prolonged reductions in heparin therapy in response to a PTT greater than three times control, leading to subtherapeutic levels in 56% of subsequent PTTs. We think that poor understanding of heparin kinetics, overcautious behavior of physicians, and high heparin requirements in this selected population account for the findings.

Female↗

Use of aprotinin in pediatric lung transplantation.

BACKGROUND: Aprotinin has been shown to decrease perioperative bleeding in adults undergoing cardiac surgery. We evaluated its efficacy in reducing blood loss in pediatric lung transplantation. METHODS: Aprotinin was given to a group of pediatric lung transplant recipients (n = 24) identified as being at high risk for bleeding by virtue of preoperative diagnosis of cystic fibrosis or previous cardiothoracic operation (group 1). Comparison was made to a group of pediatric recipients (n = 19) believed to be at low risk for bleeding who did not receive aprotinin (group 2). All transplantations were accomplished with the use of cardiopulmonary bypass. RESULTS: No difference in intraoperative blood requirement was identified between groups (18 +/- 3 cc/kg [group 1] versus 30 +/- 8 cc/kg [group 2], p = 0.16). Neither postoperative blood transfusion requirement (12 +/- 5 cc/kg [group 1] versus 16 +/- 6 cc/kg [group 2], p = 0.55) nor chest tube output in the first 24 postoperative hours (43 +/- 9 cc/kg [group 1] versus 53 +/- 13 cc/kg [group 2], p = 0.55) was significantly different between groups. Reexploration for bleeding was required in 8% (2 of 25) in group 1 and 16% (3 of 19) in group 2 (p = 0.64). CONCLUSIONS: Aprotinin reduced the amount of perioperative hemorrhage in a group of pediatric patients at high risk for bleeding after lung transplantation. The magnitude of the effect could not be quantified but was sufficient to normalize the transfusion requirement to that of a low risk group of patients.

Aprotinin↗