The pharmacokinetics of a single dose of gentamicin (4 mg/kg) as prophylaxis in cardiac surgery requiring cardiopulmonary bypass.

BACKGROUND: Cardiopulmonary bypass has complex effects on drug pharmacokinetics, which is important when considering the use of once-daily aminoglycoside regimens during cardiac surgery. AIM: To study the effects of cardiopulmonary bypass on the pharmacokinetics of a single dose of gentamicin (4 mg/kg). PATIENTS AND METHODS: Nine patients undergoing valve replacement surgery were given a single dose of gentamicin (4 mg/kg) at induction of anaesthesia and blood was taken for assay at 0, O.5, 1, 1.5, 2, 2.5, 3, 4, 6, 10, 16, 22 and 24 h following administration. The mean (range) gentamicin Cmax was 18.7 (12.4-26.3) mg/litre. Three patients had concentrations of gentamicin after 24 h of > 1 mg/litre. During cardiopulmonary bypass, the mean (range) gentamicin half-life (t1/2) was 5.1 (2.0-15.1) h and post-bypass the t1/2 was 7.1 (3.0-13.9) h. CONCLUSION: There is significant correlation between the elimination t1/2 and length of cardiopulmonary bypass (r = 0.89, P < 0.01). These results suggest that gentamicin excretion is delayed following cardiopulmonary bypass so that with dose regimens of > 4 mg/kg there is a risk of toxicity.

Aprotinin use with hypothermic circulatory arrest for aortic valve and thoracic aortic surgery: renal function and early survival.

BACKGROUND AND AIM OF STUDY: Aprotinin is widely used during high risk cardiac surgery to reduce blood loss. Concern has been expressed about the safety of aprotinin in association with hypothermic circulatory arrest for surgery of the thoracic aorta and aortic valve. METHODS: A consecutive series of 19 patients undergoing surgery of the ascending aorta and/or the aortic arch using hypothermic circulatory arrest (15 - 20 degrees C) in conjunction with the use of aprotinin were studied prospectively from January 1993 to October 1994. The indications for operation were aortic dissection (n = 15) (11 acute) or annuloaortic ectasia (n = 4); 11 were emergency procedures. Ten patients underwent aortic valve replacement as part of a composite aortic root replacement and in seven patients aortic valve resuspension was possible. RESULTS: Mean total chest tube drainage was 878 +/- 548 ml (range 300 - 2,000 ml) with a mean usage of homologous blood of 2,328 +/- 1,600 ml. All but one patient survived (mortality 5.3%). None of the survivors experienced any adverse cardiac or neurological events. Serum creatinine rose significantly from a mean of 102 +/- 17 micromol/L preoperatively, to a mean of 172 +/- 100 micromol/L postoperatively (p<0.05), however, none of the patients became anuric or required dialysis and all values returned to preoperative levels by six weeks after surgery. Median intensive care stay was two days (range 1 - 20 days) and the median postoperative hospital stay was 11 days (range 6 - 50 days). CONCLUSION: These data suggest that aprotinin in conjunction with hypothermic circulatory arrest for surgery of the thoracic aorta and aortic valve has no adverse effect on early survival. However, significant though transient postoperative renal dysfunction was commonly observed in our experience.

Systemic thromboembolism leading to myocardial infarction and stroke after fenestrated total cavopulmonary connection.

Thromboembolic phenomena involving the caval veins, right atrium, and pulmonary artery are recognised complications after the Fontan operation and other forms of total cavopulmonary connection. A rare case of systemic thromboembolism is reported in a 3 year old girl who had repeated coronary and cerebral thromboembolic events after a fenestrated total cavopulmonary shunt operation. A survey of the 18 paediatric cardiac units in the United Kingdom and Ireland showed a wide discrepancy in anticoagulation policies after Fontan-type operations. Prevention of thrombotic complications by lifelong postoperative anticoagulation may outweigh the risk of haemorrhage.

Posterior pericardiotomy reduces the incidence of supra-ventricular arrhythmias following coronary artery bypass surgery.

A prospective study of 100 patients undergoing coronary artery bypass surgery was performed to demonstrate the effectiveness of a posterior pericardiotomy in reducing the incidence of pericardial effusions and, consequently, reducing the incidence of supraventricular arrhythmias in the post-operative period. Pericardial effusion occurred in 4 of 50 patients following a posterior pericardiotomy, whereas effusion occurred in 20 of 50 patients in whom a pericardiotomy was not created (P < 0.0005). Supra-ventricular arrhythmias occurred in 4 patients in the pericardiotomy group and 18 in the group treated without pericardiotomy (P < 0.005). No complications resulted from this procedure. We conclude that pericardiotomy is a simple, safe and effective method for reducing the incidence or pericardial effusion and thereby post-operative supra-ventricular arrhythmias.

Modification of the Senning repair in a case of transposition of the great arteries with juxtaposition of the atrial appendages.

A further modification of the Senning operation is described in a case of transposition of the great vessels with juxtaposition of the atrial appendages in which the right atrial appendage was excised and used as a free graft in the construction of the venous pathways.

Prolonged survival following multiple thoracotomies for metastatic hepatoblastoma.

A 14-month-old boy presented with hepatoblastoma, which was completely excised. He had pulmonary metastases, diagnosed 1 year later, treated with chemotherapy followed by resection at age 2 1/2 years. At the age of 3 1/2 years a further metastasis was shown on CT scan and this was resected. Two further metastses were resected at ages 4 1/2 and 5 1/2 years. At age 9 1/2 he had a further isolated pulmonary metastasis resected and is again disease-free more than 30 months from the last thoracotomy. Prolonged survival following metastatic hepatoblastoma can be achieved with repeated thoracotomies, especially if the first recurrence is more than 6 months from diagnosis and the number of metastases is small. Follow-up examinations should be both radiological and with serum alpha fetaprotein (S alpha FP).

Hemodynamic effects and echocardiographic consequences of tension-free pericardial closure after heart valve surgery.

Pericardial closure early after open heart surgery has been shown to consistently lower cardiac output and stroke volume, while mean arterial blood pressure is maintained by an increase in systemic vascular resistance. In 10 patients (seven females) (mean age 65 +/- 4 years) undergoing an open heart valve procedure, the effects of a tension-free pericardial closure technique were studied using thermodilution studies and transesophageal echocardiography. The following variables were recorded: mean arterial pressure, mean pulmonary artery pressure, right atrial pressure, cardiac output, stroke volume, systemic vascular resistance, and systolic and diastolic left ventricular dimensions, and left ventricular wall thickness. Observations were made after the heart was decannulated, both while the pericardium was open and after it had been closed by a tension-free technique, and then after closure of the chest. Further observations were made while the chest remained closed, both before and after the pericardium had been reopened by removing the pericardial suture through the chest wall. Closing the pericardium with the tension-free technique while the chest remained open was followed by a fall in cardiac output by 8% and a 15% fall in systemic vascular resistance (both n.s.). These changes caused a 13% reduction in the mean arterial pressure (p = 0.03). Ejection fraction did not change, and systolic and diastolic left ventricular dimensions decreased by 6% and 4% respectively (both n.s.). Opening the pericardium (1.5 to 2 hours after the end of the operation) while the chest remained closed was not followed by significant change in any of the hemodynamic or echocardiographic variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Medium-term clinical results after the Senning procedure with haemodynamic and angiographic evaluation of the venous pathways.

OBJECTIVE: To assess the clinical condition of patients and the adequacy of their newly constructed venous pathways after the Senning operation for simple transposition of the great arteries. PATIENTS AND DESIGN: All 34 patients who had the Senning operation between March 1983 and December 1986 were reviewed. Survivors had detailed cardiac catheterisation studies one to two years later and clinical evaluation two to six years after surgery. RESULTS: There were two operative deaths (6%), one sudden late death (after two years), and 31 survivors (91%). No clinical evidence of obstructed venous pathways was found and there was no need for reoperation for any reason. The average mean (SD) pressure gradient at the junction of the superior vena cava and systemic venous atrium was 2.0 (1.7) mm Hg, although two patients had gradients of 7 mm Hg. The average gradient was 0.7 (1) mm Hg in the inferior vena caval pathway, and 1.4 (1.1) mm Hg between the mean pulmonary arterial wedge and pulmonary venous atrial pressures. Only the two patients with gradients of 7 mm Hg at the junction of the superior vena cava and the systemic venous atrium had considerable narrowing of the pathway and retrograde flow in the azygos vein to below the diaphragm. CONCLUSION: A small series of patients were comprehensively studied after the Senning operation for simple transposition of the great arteries. Scrupulous technique in the construction of the venous pathways has had excellent results with no need for reoperation for obstruction in either the systemic or pulmonary pathways. Clinical observation alone may fail to identify patients with venous pathway obstruction, therefore careful assessment is required, even in patients who are physically normal.

Diagnosis of acute thoracic aortic dissection using combined echocardiography and computed tomography.

Acute dissection of the thoracic aorta is a life-threatening emergency requiring a diagnosis which is rapid, accurate and safe, and which will distinguish between dissections involving the ascending and descending aorta. In the absence of any general agreement on the best method of making this diagnosis we studied the use of combined echocardiography and contrast-enhanced computed tomography (CT) to diagnose acute aortic dissection. Over a 3 year period 23 patients were investigated in this way. Aortic dissection was demonstrated in 18 cases, involving the ascending aorta in 15, and the descending aorta alone in three. The diagnosis of aortic dissection was confirmed in 13 patients at surgery, in one at aortography and in one at autopsy. Three patients died without surgery or autopsy being performed to confirm the diagnosis and the subsequently which accounted for their symptoms. This combined approach has proved a valuable and safe means of investigating aortic dissection.

Patterns of ductal tissue in coarctation of the aorta in the first three months of life.

A possible relationship between recurrence of coarctation and the presence of residual ductal tissue in the aorta was studied by defining the presence and pattern of ductal tissue in aortic segments from 23 patients less than 3 months of age who underwent resection of coarctation of the aorta. The surgical policy was to perform extensive excision of the coarctation, including a wide margin of descending aorta beyond the ductus arteriosus. Histologic examination showed that there was a circumferential sling of ductal tissue extending from the ductus arteriosus and surrounding the aorta at the level of the coarctation shelf in 22 specimens. In 15 of these specimens one or two tonguelike prolongations of ductal tissue extended distally from the circumferential sling and occupied constant positions in the aortic wall; one tonguelike prolongation extended distally below the insertion of the ductus and the other from the circumferential sling opposite the ductal insertion. Incomplete excision of ductal tissue was found in 11 specimens. In relation to the goal of avoiding recurrent coarctation after repair in the early months of life, the possible implications of these findings are discussed, and, in particular, a possible mechanism of recurrence after subclavian flap aortoplasty is proposed.

Distal aortic pressure during coarctation operation.

Mean distal aortic pressure (DAP) was monitored continuously during operative repair of coarctation of the aorta in 67 children more than 1 year of age between 1982 and 1987. At initial test clamping a DAP of 45 mm Hg or more was considered adequate. In 42 patients (group A), DAP exceeded 45 mm Hg and the operation proceeded. In 25 patients (group B) the DAP was less than 45 mm Hg, and adjustments were made to the position of the proximal and distal clamps and in the use of hypotensive agents. After these adjustments in group B, DAP rose from 34.7 to 50.6 mm Hg (p less than 0.001), achieving the desired level in all but 5 patients, who required temporary shunts to support the distal circulation. The adjustments were as follows: the left subclavian artery was open in 28% of patients before and 60% after (p less than 0.02); no more than one pair of intercostal arteries was clamped in 64% before and 88% after (p less than 0.05); and no hypotensive agents were used in 56% before and 80% after (p = 0.07). During the first ten minutes of cross-clamping the DAP rose by 5.5 mm Hg (p less than 0.01, n = 52). It is concluded that continuous monitoring of DAP contributed to the operative management of these patients by indicating when adjustments in the position of the clamps or in the use of hypotensive agents were needed. The use of hypotensive agents should be reduced to achieve a higher DAP.

Tracheobronchial mucoepidermoid carcinoma in childhood with a ten year follow-up.

Tracheobronchial mucoepidermoid carcinoma in childhood is extremely rare. The patient described was treated by pneumonectomy and is the third reported with a long-term follow-up. The pathology, surgical options and the past experience with this tumour are reviewed.

The Bristol Children's Hospital experience of tracheobronchial foreign bodies 1977-87.

In the 11 years 1977 to 1987, 36 confirmed cases of tracheobronchial foreign body were seen in the Bristol Children's Hospital. The distribution of ages, sites, and natures of the objects inhaled are similar to those in other reviews. Complications of removal of the foreign body once diagnosed were few, and have been absent since the Storz rod lens system was introduced in 1982. Eleven patients experienced delay of at least 7 days between the beginning of the symptoms and diagnosis, of whom 3 subsequently required open thoracotomy. Six of these had sought medical advice during this period, of whom 4 had a positive history of choking or inhalation. Inhaled foreign bodies remain a source of diagnostic difficulty, although this should be improved by greater attention to history and appropriate investigation. Technical advances have ensured their safe bronchoscopic removal in most cases.

Compartment syndrome in a five-year-old child following femoral cannulation for cardiopulmonary bypass.

The compartment syndrome is uncommon in children. It has been seen following bony trauma and has also been reported in two patients following cardiac catheterisation. We report its occurrence in a 5-year-old child following femoral artery and femoral vein cannulation for cardiopulmonary bypass. We believe that the presence of a cannula in the femoral vein as well as in the artery was an important factor in impeding the circulation and thus causing the compartment syndrome. Prompt diagnosis and early fasciotomy saved the limb from amputation; however, a residual footdrop persists. The development of the compartment syndrome following femoral cannulation for cardiopulmonary bypass has not been reported previously.

Combined chemotherapy and surgery for pulmonary metastases from osteogenic sarcoma. Results of 10 years experience.

Twenty-three patients presented with isolated pulmonary metastases from osteogenic sarcoma following primary treatment by amputation or limb salvage, combined with chemotherapy. The metastases were treated by conservative surgical excision combined with chemotherapy; surgical excision was repeated for recurrent pulmonary metastases, provided there were none elsewhere. Six patients are alive and disease-free following their initial surgery. Of the remaining 17, 10 had recurrence confined to the lungs, and 7 developed extra-pulmonary metastases. The 10 with isolated pulmonary metastases all had further thoracotomies but eventually 7 died, as did all those with extra-pulmonary metastases. There were in all 45 operations, with 1 hospital death and 1 serious complication. Actuarial survival at 1, 3, 5 and 7 years was 87%, 45%, 39% and 31%, respectively. In the 10 patients who had recurrence of isolated pulmonary metastases, survival at 1 and 3 years was 70% and 34%.

Management of Pulmonary Metastases in Osteogenic Sarcoma.

Twenty-three patients presented with isolated pulmonary metastases from osteogenic sarcoma following primary treatment by amputation or limb salvage, combined with chemotherapy. The metastases were treated by conservative surgical excision, combined with chemotherapy; surgicl excision was repeated for recurrent pulmonary metastases provided there were none elsewhere. Six patients are alive and disease free following their initial surgery. Of the remaining 17, 10 had recurrence confined to the lungs, and seven developed extra pulmonary metastases. The ten with isolated pulmonary metastases all had further thoracotomies but eventually seven died, as did all those with extra pulmonary metastases. There were in all 45 operations, with one hospital death and one serious complication. Actuarial survival at 1,3,5 and 7 years was 87, 45, 39 and 31% respectively. In the ten patients who had recurrence of isolated pulmonary metastases, survival at 1 and 3 years was 70 and 34%.