Ulf Abdel-Rahman

Surgical treatment of tracheomalacia by bronchoscopic monitored aortopexy in infants and children.

BACKGROUND Aortopexy has become an established surgical procedure for the treatment of severe tracheomalacia (TM) in infancy. However, postoperative outcome may be improved by intraoperative bronchoscopic control of the aortopexy. METHODS Between 1992 and 2000, 16 infants and children (2 female, 14 male) with TM were treated by pexis of the aorta via a right (15 patients) or left (1 patient) anterior thoracotomy. Patients age ranged from 4 to 122 months (mean, 26 mon). Three infants had previous surgery for esophagus atresia and tracheoesophageal fistula. Another four patients were operated for gastroesophageal reflux. In all cases, the aortopexy was monitored intraoperatively by bronchoscopy. Respiratory function was verified for each patient by comparing pre- and postoperative tidal expiratory flow values (TEF 25% in ml/sec). RESULTS Mean follow-up was 36 months (range, 2 to 60 mo). There was no intraoperative or postoperative mortality. 13 patients showed permanent relief of symptoms. Postoperative median TEF 25% increased significantly compared with preoperative values (81 ml/sec vs. 56 ml/sec; p = 0.016). In one patient repeat aortopexy was necessary. CONCLUSIONS Aortopexy through a right anterior thoracotomy is an efficient and feasible method in the surgical treatment of TM in infancy and, therefore, can improve postoperative respiratory function. Intraoperative bronchoscopy is advantageous.

Occupational exposure to inhalational anesthetics during cardiac surgery on cardiopulmonary bypass

BACKGROUND Eventual hazards from occupational exposure of operating room personnel to inhalational anesthetic agents cannot yet be definitively excluded. We determined if occupational exposure of operating room personnel to waste anesthetic gases during cardiopulmonary bypass (CPB) complies with the established governmental limits. METHODS Ten adults underwent inhalational anesthesia for coronary artery bypass grafting with nitrous oxide and either sevoflurane (n = 5) or desflurane (n = 5). The administration of inhalational anesthetic agents was stopped before initiation of CPB. Gas samples were obtained before and during CPB every 90 seconds from the breathing zones of anesthesiologist (A), surgeon (S), and perfusionist (P). Time-weighted averages (TWA) over the time of exposure were calculated. RESULTS The surgeons exposure to nitrous oxide was 9.3 +/- 1.9 parts per million (ppm) before and 3.0 +/- 1.4 ppm during CPB (A: 6.7 +/- 1.1 ppm and 0.5 +/- 0.1 ppm; P: 3.7 +/- 1.4 ppm during CPB). Occupational exposure to desflurane was 0.21 +/- 0.10 ppm before and 0.62 +/- 0.28 ppm during CPB for the surgeon (A: 0.02 +/- 0.01 ppm and 0.02 +/- 0.003 ppm; P: 0.82 +/- 0.26 ppm during CPB), thereby exceeding the given limit of 0.5 ppm. Exposure levels of sevoflurane were below the 0.5 ppm limit at all times, as were nitrous oxide levels (threshold limit: 25 ppm). CONCLUSIONS Although occupational exposure to inhalational anesthetic agents was low at most times during the study and none of the operating room staff complained about subjective or objective impairment or discomfort, all measures must be taken to further minimize occupational exposure, including sufficient air conditioning and routine use of waste gas scavenging systems on CPB equipment.

Correction of simple congenital heart defects in infants and children through a minithoracotomy

BACKGROUND Minimally invasive surgical techniques in pediatric cardiac surgery have evolved throughout the last 10 years. Advantages of minimally invasive procedures include excellent cosmetic results and superior postoperative outcome. However, safety of minimally invasive techniques has to be proven. METHODS In 21 female infants and children, a right anterolateral thoracotomy was performed. Mean age was 7.1 years (0.5 to 16.6 years) and mean body weight was 20.8 kg (8.3 to 56 kg). The following defects were repaired: atrial septum defect type II (n = 14); partial atrioventricular septum defect (n = 3); partial anomalous pulmonary venous connection (n = 2); ventricular septum defect (n = 2); mitral valve insufficiency (n = 1); and resection of an embolized atrial septum defect occluder (n = 1). In two cases, aortic cross-clamping was performed by using a transthoracic clamp. In 5 patients, femoral cannulation was performed. Skin incisions were limited to 4 to 7 cm. RESULTS There was no operative or late mortality. Mean operation time, bypass time, and aortic cross-clamp time were 138 (95 to 275), 72 (32 to 179), and 35 (12 to 120) minutes, respectively. Mean postoperative mechanical ventilation time, mean intensive care unit stay, and mean hospital stay were 3.9 hours (1 to 12 hours), 1.4 days (1 to 3 days), and 12 days (8 to 18 days), respectively. Postoperative complications included hemorrhage in 1 patient requiring surgical intervention. Mean follow-up period was 13.3 months (1 to 36 months). All patients were in New York Heart Association class I postoperatively. Trivial mitral insufficiency was evident in 1 patient operated for partial atrioventricular septum defect. CONCLUSIONS A small right anterolateral thoracotomy as a minimally invasive technique in pediatric cardiac surgery is a safe and suitable alternative in the operative management of simple congenital heart defects. Cosmetic results are superior, however, improved postoperative outcome has to be proven.

Synthetic protein treated versus heparin coated cardiopulmonary bypass surfaces: similar clinical results and minor biochemical differences

OBJECTIVE Complications associated with cardiopulmonary bypass (CPB) have gained more attention due to increased interest in coronary artery bypass grafting without CPB. The impact of heparin coating of CPB circuits has been discussed controversially. The present study examines if the treatment of the oxygenator surface with a synthetic protein may serve as an alternative to a completely heparin coated circuit. METHODS Fifty-eight patients undergoing coronary artery bypass grafting with CPB were randomly assigned to completely heparin coated circuits or synthetic protein treated oxygenators in a double blind protocol, focussing on the inflammatory reaction resulting in membrane damage, coagulation changes and markers of cerebral injury or dysfunction. Treatment groups did not differ as to preoperative demographics, and intraoperative clinical data. Patients with any neurologic disease or risk factors for cerebral dysfunction were not included in the study. RESULTS Postoperative clinical data did not differ between groups. Both surface treatments resulted in similar coagulation activation, hyperfibrinolysis and disseminated intravascular coagulation. Platelet count displayed a difference in favour of the heparin coated group (P = 0.029). Increased leukocyte activation reflected by rising myeloperoxidase concentrations on CPB was present in both synthetic protein and heparin coating groups. Interleukins 6 and 8 reacted similarly, but interleukin 8 increased significantly more (P = 0.0061) at the end of surgery in patients treated with protein treated oxygenators. The same pattern was observed for complement activation as determined by total complement complex (P = 0.006). Both surface changes resulted in moderately increased S-100B protein and neuron specific enolase, without difference between groups. Both markers did not reach concentrations associated with clinical manifestation of cerebral injury. CONCLUSIONS These results in routine patients with short bypass time, imply that protein treated oxygenators are associated with a limited increase of biochemical markers similar to heparin coating. However, significantly lower interleukin 8 release and complement activation can be achieved by heparin coating. The protein treatment is a standard feature of the oxygenator examined in both groups. It is not associated with additional cost and therefore appropriate for use in routine patients.

The use of minimized extracorporeal circulation system has a beneficial effect on hemostasis--a randomized clinical study.

BACKGROUND Conventional cardiopulmonary bypass (CPB) is associated with increased coagulation and fibrinolytic activity. A closed miniaturized bypass circuit (CorX) features a significantly reduced tubing set, an integrated pump, and an air removal system without a cardiotomy reservoir. In a prospective randomized trial, the effects on hemostasis were investigated while comparing CorX with conventional CPB in patients undergoing coronary artery bypass grafting. METHODS Over a period of 1 year, 81 patients were randomly assigned either to the CorX system (n = 39, group A) or standard CPB system (n = 42, group B). Primary endpoints were platelet count, plasmin-antiplasmin complex (PAP), prothrombin fragments 1+2 (F1+F2), D-dimers, and fibrinogen. Secondary end-points were hematocrit, blood loss in the first 12 hours postoperatively, transfused packed red blood cells, and fresh frozen plasma in the first 24 hours postoperatively. In addition, we analyzed partial thromboplastin time, prothrombin time, and antithrombin III. RESULTS After aortic declamping, PAP complex and prothrombin F1+F2 were significantly lower in group A than in group B. The difference in D-dimers between groups reached significance at 1 hour post-CPB. Hematocrit values at the end of CPB measured 26 +/- 6% in group A versus 22 +/- 4% in group B (P = .01). The rest of the observed parameters did not significantly differ between groups. CONCLUSION Postoperative blood loss was not reduced in the present study. However, the use of the CorX system leads to a significant suppression of activation of coagulation and fibrinolytic cascades compared to conventional CPB, suggesting that miniaturized extracorporeal circuits are a step forward toward reduced imbalance of hemostasis in cardiac surgery.

Hypoxic reoxygenation during initial reperfusion attenuates cardiac dysfunction and limits ischemia-reperfusion injury after cardioplegic arrest in a porcine model.

OBJECTIVE In clinical practice, reperfusion of ischemic myocardium usually occurs under high arterial oxygen levels. However, this might aggravate cardiac ischemia-reperfusion injury caused by excessive oxidative stress. In an experimental in vivo study, the cardioprotective role of hypoxic reoxygenation during initial reperfusion was assessed. METHODS Twenty-one adult pigs were started on cardiopulmonary bypass with aortic crossclamping (90 minutes) and cardioplegic arrest. During initial reperfusion, 10 pigs underwent standard hypoxic reoxygenation (Pa(O(2)), 250-350 mm Hg), whereas gradual reoxygenation (Pa(O(2)), 40-90 mm Hg) was performed in 11 pigs. Cardiac function was analyzed by means of the thermodilution method and conductance catheter technique. RESULTS In both groups cardiac index was decreased 10 minutes after cardiopulmonary bypass compared with preoperative values. Sixty minutes after cardiopulmonary bypass, cardiac index improved significantly after gradual reoxygenation compared with that after hypoxic reoxygenation (3.2 +/- 0.6 vs 2.5 +/- 0.5 L min(-1) m(-2), P = .04). Correspondingly, end-systolic pressure-volume relationship and peak left ventricular pressure increase were significantly less decreased in the gradual reoxygenation group. During and after reperfusion, malondialdehyde and troponin T values within the coronary sinus were significantly lower after gradual reoxygenation (60 minutes after declamping: malondialdehyde, 7.6 +/- 0.8 vs 4.6 +/- 0.5 micromol/L [P = .007]; troponin, 0.12 +/- 0.02 vs 0.41 +/- 0.12 ng/mL [P = .02]). CONCLUSION Hypoxic reoxygenation at the onset of reperfusion attenuates myocardial ischemia-reperfusion injury and helps to preserve cardiac performance after myocardial ischemia in a pig model.

Aortopexy in Infants and Children—Long-term Follow-up in Twenty Patients

BackgroundAortopexy has become an established surgical procedure for the treatment of tracheomalacia (TM) in infants and children. The aim of the present study was to evaluate the clinical outcome and respiratory function after aortopexy in the long term.MethodsBetween 1992 and 2006, 20 patients (6 female, 14 male) with TM were treated by bronchoscopically monitored pexis of the aorta via a right anterior thoracotomy. Patient age ranged from 4 months to 11 years (mean: 29 months). Five infants had previous surgery of esophageal atresia or tracheo-esophageal fistulae, and five other patients were operated on for gastroesophageal reflux. Postoperative tidal expiratory flow (TEF25%) was compared to age-related values.ResultsMean follow-up was 7.8 years (range: 13 months to 10.7 years). There was no early or late mortality. Most patients (n = 16) showed immediate and permanent relief of symptoms. Compared to corresponding age groups, median TEF25% was slightly but not significantly decreased after aortopexy (p = 0.15). In one patient a re-aortopexy was necessary. Another patient experienced recurrent tracheo-esophageal fistula 3 years after aortopexy.ConclusionsThe bronchoscopically guided aortopexy is an efficient and simple method in the surgical treatment of TM in infants and children. The follow-up data in this series of 20 patients showed improvement of respiratory function and permanent relief of symptoms in the long term.

Biventricular Pacing for Successful Weaning from Extracorporal Circulation in an Infant with Complex Tetralogy of Fallot

AbstractBiventricular pacing therapy is an innovative therapy for improving cardiac output in adult patients with severe heart failure. However, this technique is not yet used in infants with congenital heart disease. We present a six month old infant with tetralogy of fallot and atresia of the left pulmonary artery in which biventricular stimulation led to improved left ventricular function and successful weaning from extracorporeal circulation.

Inhibition of neutrophil activity improves cardiac function after cardiopulmonary bypass

BackgroundThe arterial in line application of the leukocyte inhibition module (LIM) in the cardiopulmonary bypass (CPB) limits overshooting leukocyte activity during cardiac surgery. We studied in a porcine model whether LIM may have beneficial effects on cardiac function after CPB.MethodsGerman landrace pigs underwent CPB (60 min myocardial ischemia; 30 min reperfusion) without (group I; n = 6) or with LIM (group II; n = 6). The cardiac indices (CI) and cardiac function were analyzed pre and post CPB with a Swan-Ganz catheter and the cardiac function analyzer. Neutrophil labeling with technetium, scintigraphy, and histological analyses were done to track activated neutrophils within the organs.ResultsLIM prevented CPB-associated increase of neutrophil counts in peripheral blood. In group I, the CI significantly declined post CPB (post: 3.26 ± 0.31; pre: 4.05 ± 0.45 l/min/m2; p < 0.01). In group II, the CI was only slightly reduced (post: 3.86 ± 0.49; pre 4.21 ± 1.32 l/min/m2; p = 0.23). Post CPB, the intergroup difference showed significantly higher CI values in the LIM group (p < 0.05) which was in conjunction with higher pre-load independent endsystolic pressure volume relationship (ESPVR) values (group I: 1.57 ± 0.18; group II: 1.93 ± 0.16; p < 0.001). Moreover, the systemic vascular resistance and pulmonary vascular resistance were lower in the LIM group. LIM appeared to accelerate the sequestration of hyperactivated neutrophils in the spleen and to reduce neutrophil infiltration of heart and lung.ConclusionOur data provides strong evidence that LIM improves perioperative hemodynamics and cardiac function after CPB by limiting neutrophil activity and inducing accelerated sequestration of neutrophils in the spleen.

Initial in vivo results of the new Medtronic AdvantageTM bileaflet valve in aortic position and comparison to the SJM

The present study investigated the Medtronic Advantage (MA) bileaflet valve in an animal model and compared the results to the St. Jude Medical (SJM) valve. Systolic performance and coronary artery flow in different orientations were studied.A rotation device holding either a MA or SJM aortic valve size 23 mm was implanted into eight pigs. Transvalvular pressure gradients and ventricular dimensions were investigated with the valves in different orientations. Coronary artery flow was measured at normal and high cardiac output. Orientation significantly influenced the hemodynamic performance of both valves. The best results for both valves were obtained with one orifice proximal to the right cusp. Pressure gradients and ventricular dimensions of the MA corresponded to the SJM. Coronary artery flow was higher for the MA. The systolic performance of the new MA bileaflet valve was similar to the SJM. During diastole, the MA showed significantly higher LAD coronary flow.