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Biomedical subjects

I M Mitchell

Publications and source records attributed to I M Mitchell.

30 records · Page 2Linked to original sources

Patent ductus venosus.

A patent ductus venosus has been reported on only two previous occasions. Both involved adults who presented with recurrent bouts of encephalopathy. We present the case of an infant with complex congenital heart disease and multiple other abnormalities, in whom a patent ductus venosus was an incidental finding at necropsy. The etiology of this condition and the options for management are discussed.

Congenital Abnormalities↗

Transcutaneous iodine absorption in infants undergoing cardiac operation.

Povidone-iodine is an effective antiseptic, but its topical use has been associated with a number of adverse reactions in burn patients and in neonates as a result of transcutaneous absorption. In particular, high plasma iodine concentrations are known to cause renal failure, metabolic acidosis, and thyroid suppression. Because of the permeable nature of the skin in small infants and the large areas cleaned before cardiac operations, it is possible that significant transcutaneous iodine absorption might occur in this situation. We have studied 17 infants, less than 3 months of age, who were undergoing closed cardiac or thoracic procedures. After povidone-iodine skin preparation in 15 (covering 20% to 30% of body surface area), plasma total iodine concentrations rose fourfold (range, 160% to 1,440%). This increase was significantly different from the preoperative level at 6, 12, 18, and 24 hours. There was no increase in plasma iodine concentration in 2 patients who were not exposed to povidone-iodine or any other iodine-containing compound. We discuss the implications for a topical antisepsis policy in infants.

Body Surface Area↗

Coarctation of the aorta and post-stenotic aneurysm formation.

Despite earlier angiography, post-stenotic aneurysm of the aorta was an unexpected finding at operation in two patients with coarctation. One aneurysm was found in an intercostal artery in a 19 year old man and the other was a false aneurysm just distal to the coarctation site in a 7 year old boy. These aneurysms are fragile, apt to rupture, and difficult to diagnose preoperatively. Though local factors such as jet streams and bacterial endocarditis may influence their formation there must be an underlying generalised weakness in the arterial wall. A coarctation should not be regarded as an isolated arterial abnormality because it may be a feature of a more generalised disease. Because of the risk of rupture, which may not be prevented by antihypertensive treatment, operation should not be delayed in any age group.

Adult↗

Colon interposition in children.

Since 1960 we have performed 80 colonic interpositions on 79 children. We present a retrospective review of their progress. Sixty-nine interpositions were for long-gap oesophageal atresia, while the remainder followed oesophagectomies, eight for strictures and two others. Overall, the transthoracic route was used in 69 per cent of cases, while 29 per cent were retrosternally placed and one was retropleural. The mean follow-up was 11.08 years. The mortality rate was 12 per cent, with one-third of deaths unrelated to the operation. Graft failure, which occurred on eight occasions (10 per cent), was due to ischaemia in four, intractable stricture in two and stomal ulceration in two. Leakage from the proximal anastomosis occurred in 31 per cent of cases and stricture formation in 27 per cent. Thirty per cent of patients complained of acid reflux, of whom one-third developed stomal ulceration. We present data concerning other complications, including long-term recurrent respiratory infections, malabsorption, gastrointestinal haemorrhage, diarrhoea, intestinal obstruction and redundancy of the graft. Staging the procedure did not affect the outcome, however the higher incidence of serious complications encountered following retrosternal interposition finally led us to abandon this procedure in favour of the transthoracic route. There has been little improvement in the growth rate, but in terms of swallowing ability the outcome was satisfactory in 94 per cent of cases.

Adolescent↗

Emergency subtotal oesophagectomy.

From 1981 to 1987 nine patients have undergone resection and reconstruction of the oesophagus as an emergency, using a two-part left-sided approach with oesophagogastric anastomosis in the neck. Five patients had oesophageal perforation with a carcinoma; one had spontaneous perforation of an intrathoracic stomach; two had severe haemorrhage; and one had acute sterile mediastinitis. Following operation there was one postoperative death (11 per cent) and no major complications. Long-term survival was marred only by the development of further malignancy in four patients. Subtotal oesophagectomy has both theoretical and practical advantages over conventional oesophagogastrectomy in oesophageal emergencies and we suggest that it should be considered as the method of choice in the management of these difficult cases.

Adult↗

Pulmonary artery versus left ventricular venting: a radioisotope study of left ventricular function.

Radionuclide measurements of ejection fraction were used to assess immediate and late postoperative ventricular function after the use of either a pulmonary artery vent (group A) or a left ventricular vent (group B) in 20 patients undergoing aortic valve replacement for pure aortic stenosis. Ten patients were included in each group and anesthetic techniques, patient management, and septal temperatures were similar in all cases. No significant difference was found between the preoperative and immediate or 6-week postoperative ejection fractions, either taken overall or between the two groups (p greater than 0.05; Student's t test). No correlation was found between cross-clamp time, bypass time, or the occurrence of ventricular fibrillation and the immediate postoperative ejection fraction (p greater than 0.05; Student's t test). There was no significant difference in the incidence of ventricular fibrillation after each type of vent had been used (chi 1(0) = 3.32; p greater than 0.05). We did not demonstrate any abnormalities in regional wall motion associated with apical insertion of a left ventricular vent, and conclude that pulmonary artery and left ventricular vents are equally satisfactory in terms of postoperative ventricular performance.

Adult↗

The return of stereotaxic surgery.

Stereotaxic surgery, which declined with the advent of dopaminergic treatment of Parkinson's disease, has found new life and new uses with unknown limits.

Biopsy↗

Creation of brachial artery-basilic vein fistula. A supplement to the cavopulmonary shunt.

Since 1984 five patients who had previously had cavopulmonary shunts for cyanotic congenital heart disease have returned to the Birmingham Childrens' Hospital with increasing breathlessness and cyanosis. Two had had a classic Glenn (unidirectional) cavopulmonary shunt and three, a bidirectional shunt; all shunts had been performed 5 to 18 years earlier. Each patient was reinvestigated and underwent creation of a brachial artery-basilic vein fistula. This procedure is known to have good patency rates when used in other situations (for example, for hemodialysis), but it has not been previously described for use in this context. Of the five patients, four had a considerable and sustained symptomatic improvement on follow-up of 12 to 49 months (mean 31 months), but the condition of one continued to deteriorate; that child has subsequently undergone a Fontan procedure, also with no improvement. Only one patient complained of coldness of the arm, and there were no other complications. We believe a brachial artery-basilic vein fistula has considerable advantages in terms of ease of operation and postoperative complications when compared with an axillary arteriovenous fistula, used as a supplement to an inadequate cavopulmonary shunt.

Adolescent↗

Surgical treatment of idiopathic mediastinal fibrosis: report of five cases.

Idiopathic mediastinal fibrosis is a rare disease of unknown aetiology. It is a benign condition in which abnormal proliferation of fibrous tissue occurs within the mediastinum, leading to constriction and obliteration of local structures, particularly the great veins. It is a rare cause of superior vena caval obstruction (1-2%) but one that is potentially amenable to surgical palliation. The results of venous reconstruction in five patients with superior vena caval obstruction secondary to idiopathic mediastinal fibrosis are reported. Reversed autogenous saphenous vein grafts were used in two patients, woven silicone rubber prostheses in two, and bovine pericardial conduits in one patient. Useful long term results were obtained in three patients, but the bovine pericardial graft and one of the vein grafts failed within a few weeks.

Adult↗