Biomedical subjects
Publications and source records attributed to F C Wells.
A case of saccular diverticulum of the oesophagus occurring at the site of enucleation of an oesophageal leiomyoma is presented. Implication for surgical therapy are discussed.
A fistula between the aorta and right atrium which communicates with the right ventricle is an extremely rare and rapidly lethal complication of aortic dissection. There are only three previously reported cases of survival after operative repair of aorto-right atrial fistulae in the literature. We describe a patient who experienced acute aortic dissection with fistula formation to the right atrium and to the right ventricle. The patient underwent successful operative repair.
Platelet damage during cardiopulmonary bypass (CPB), although proportional to the duration of bypass, may result in significant dysfunction after the initial contact with an extracorporeal circuit, the so-called 'first pass' phenomenon. The platelet sparing effect of prostacyclin (PGI2) infusion was studied in a double-blind randomized trial on male patients undergoing coronary artery bypass grafts to assess the effect of the 'first pass' through the CPB circuit. Prostacyclin infusion was begun before the onset of CPB or during CPB in two groups which were compared to a placebo control group. A standardized anaesthetic, surgical and perfusion technique were used. Preoperatively and during surgery at pre-set intervals, whole blood platelet aggregation was studied using ADP and collagen agonists. Platelet numbers and function measured by ADP aggregation were conserved in the two PGI2 groups. There was no significant difference between the treated groups. We conclude, therefore, that the initial contact of platelets with the CPB circuit, in the absence of PGI2 did not irreversibly affect platelet function. In addition, the hypotensive action of PGI2 was easier to control once on bypass. It may therefore be preferable to delay PGI2 infusion until CPB has been established.
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During the period January 1985 to June 1989, 53 cases of empyema thoracis were treated surgically at Papworth hospital regional cardio-thoracic centre. Of these, 47 patients underwent thoracotomy and decortication as their primary surgical treatment. The remaining six patients were treated by rib resection. Prior to surgical referral 20 of these had undergone previous tube drainage for a mean period of 18 days (range 7-42 days). The principle cause of empyema was broncho-pulmonary infection. In 57% of cases no organisms were isolated from pleural debris or fluid. In the remainder, a variety of organisms were encountered. Early surgical drainage and freeing of the underlying lung met with good results and no deaths in the uncomplicated group. The median duration of postoperative chest drainage for the whole group was 7 days (mean 12 days) and median postoperative in-hospital stay was 13 days (mean 20 days). This is in stark contrast to the duration of hospitalization of patients prior to surgical referral (mean 103.6 days). There were five deaths. All occurred in patients with severe debilitating associated illnesses. In these patients initial drainage of the empyema space with a tube or by rib resection may have allowed recovery prior to more major surgery.
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A multi-channel phrenic nerve stimulator developed in Tampere has been implanted into seven patients with C2-tetraplegia and into three patients with central sleep apneas. Six bipolar cuff electrodes were implanted bilaterally into the neck. Two four-pole cuff and 14 four-pole noncuff electrodes were used in seven patients and to replace one bipolar electrode. Four-pole electrodes were implanted within the thorax. Seven patients achieved total independence from conventional ventilators within 4 months of implantation, and one for 18 hours each day. Two patients died 12 days and 3 months after implantation and two patients after having achieved independence from mechanical ventilators from causes unrelated to the stimulators. Reoperations were necessary because of dislocation of receivers, electrodes, electrode lesions, nerve injuries, and technical failures in seven patients. Most of the problems appeared in two patients with obesity and in three patients with very thin phrenic nerves. Single unit prototypes failed technically more frequently than units of prototype serial fabrication. New electrode design, progress in the manufacture of receivers, and improved implantation technique should help to diminish failures in future.
Endothelium-dependent vasorelaxation mediated by endothelium-derived relaxing factors (EDRF) has been extensively studied in animals but only limited studies in man are available. Demonstration of EDRF-mediated dilatation of human vessels is fundamental for understanding the mechanisms of vascular diseases in man. We have investigated endothelium-dependent relaxation of isolated human pulmonary arteries. Vascular segments, taken from uninvolved regions of resected lung from eight patients undergoing lobectomy for lung carcinoma, were cut into rings. In rings precontracted with phenylephrine, both acetylcholine (ACh) and adenosine diphosphate (ADP) induced dose-dependent relaxation in the presence of endothelium but not when the endothelium had been carefully removed. The rings without endothelium relaxed completely with sodium nitroprusside, a vasodilator agent acting directly on vascular smooth muscle. Pre-incubation with indomethacin, a cyclo-oxygenase inhibitor which blocks production of prostacyclin, did not alter the vasorelaxant responses to ACh and ADP, suggesting that one (or several) non-prostanoid EDRF(s) are responsible for the endothelium-dependent relaxation of isolated human pulmonary arteries.
The stimulant effects of adrenaline and noradrenaline on contractile force and adenylate cyclase, mediated through beta 1 and beta 2-adrenoceptors, are analysed in isolated atrial and ventricular myocardium of man. The tissues were obtained from patients without advanced heart failure undergoing heart surgery. Usually, both adrenaline and noradrenaline stimulated adenylate cyclase predominantly through ventricular and atrial beta 2-adrenoceptors. Because the relative density of beta 2-adrenoceptors is usually smaller than that of beta 1-adrenoceptors, stimulation of one beta 2-adrenoceptor leads to the production of up to 10 times more cyclic AMP molecules than does stimulation of one beta 1-adrenoceptor. Adrenaline and noradrenaline maximally enhance contractile force through both atrial and ventricular beta 1-adrenoceptors. Adrenaline can also maximally enhance contractile force through atrial beta 2-adrenoceptors. In the ventricle, adrenaline increases force via beta 2-adrenoceptors by up to 60% of its maximal beta 1 response. Noradrenaline can increase atrial and ventricular contractile force through beta 2-adrenoceptors but only at high concentrations. Unexpectedly, in atria from patients treated with the beta 1-selective antagonist atenolol, contractile responses to adrenaline are markedly and selectively augmented through activation of beta 2-adrenoceptors. In atria from atenolol-treated patients equi-inotropic concentrations of adrenaline and noradrenaline acting through beta 2 and beta 1-adrenoceptors, respectively, cause similar increases of cyclic AMP and of cyclic AMP-dependent protein kinase activity.
For a study of penetration of enoxacin into lung, patients undergoing pneumonectomy were given 400 mg by mouth the night before and again approx 2 h before operation. A blood sample was taken as the lung was excised. Lung and serum enoxacin concentrations were assayed by high pressure liquid chromatography. Results from 15 patients showed that enoxacin was concentrated in the lung. Enoxacin lung concentrations were 3.2-13.1 mg/l, and ratios of lung to serum concentrations were 3-6 (mean, 4.2).
Yield pressure at the cardia was measured before and after fundoplication in 10 patients; five had a Nissen fundoplication and five a Belsey mark IV procedure. Surgery was considered successful if oesophagitis healed or if 24 hour pH monitoring returned to normal. There was a marked rise in yield pressure in all eight patients with a successful operation. Yield pressure remained low in two patients in whom oesophagitis persisted.
Three aspects of surgical hand hygiene have been studied: the attitude of the surgeon, the microbiology of glove changing during an operation, and the use of antiseptic-coated gloves together with different handwash routines. The survey revealed that the predominant factor in choice of agent for surgical hand hygiene was skin tolerance. The microbiological studies showed that 'closed' glove changing was to be preferred to 'open' changing, and that antiseptic-coated gloves further suppressed the skin flora, even after prolonged operations, compared to standard gloves.
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Between April 1984 and July 1986, 14 patients underwent heart-lung transplantation at Papworth Hospital, Cambridge, England. The donors for the first five operations were brought to our hospital and the organs removed in the operating theater adjacent to that in which the recipients were prepared. Subsequently, organs have been procured from distant centers. The total ischemic time ranged from 48 to 51 minutes (mean 49.6) for the near procurement group and from 70 to 186 minutes (mean 123.6) for the distant procurement group. Our method of preservation consists of cold cardioplegic arrest of the heart with St. Thomas' Hospital solution followed by a single cold (4 degrees C) pulmonary artery flush with a solution containing 500 ml donors blood, 700 ml Ringer's solution, 200 ml 20% salt-poor albumin, 100 ml 20% mannitol, 20 micrograms prostacyclin, and 10,000 units heparin. Function of the lungs after implantation was assessed by measuring the alveolar-arterial oxygen gradient. The median alveolar-arterial oxygen gradient measured shortly after discontinuation of bypass (point 1), just before extubation (point 2), and at 1 week (point 3) were 96.0, 62.3, and 18.8 mm Hg, respectively, for the near procurement group and 91.5, 60.0, and 11.3 mm Hg, respectively, for the distant procurement group. Comparison of the two groups at the three measurement points by the nonparametric Wilcoxon test showed no significant difference (p = 0.44, 0.52, and 0.11, respectively). The two groups showed significant decline of the alveolar arterial oxygen gradient differences over the first week (p = 0.004, nonparametric Friedman test). We conclude that our method of preservation provides a satisfactory function after implantation. The alveolar-arterial oxygen gradient differences were high immediately after implantation but decreased significantly afterward.
The introduction of cis-platinum-based chemotherapy has dramatically improved the prognosis for patients with primary nonseminomatous germ cell tumors of the mediastinum. Since 1978, 12 male patients (mean age, 29 years) have been seen with a large mediastinal mass, normal testes, and abnormal testicular tumor markers. Eleven patients had raised alpha-fetoprotein levels (median, 1,300 micrograms/L; normal, less than 10 micrograms/L), and 3 had elevated levels of the beta fraction of human chorionic gonadotropin (median, 8,000 IU/L; normal, less than 5 IU/L). Two patients were treated by primary surgical intervention followed by chemotherapy. Ten patients were treated with primary chemotherapy (cis-platinum, vinblastine sulfate or etoposide, and bleomycin sulfate), and this was followed by timed surgical excision of the tumor mass in 7. Six (60%) patients responded to primary chemotherapy with normalization of tumor markers. In this group there was 1 postoperative death and 1 recurrence. The 4 remaining patients are alive and free from disease at a mean of five years. Of the 4 patients with persistently elevated tumor markers, 2 died within six months, 1 is alive with recurrence, and 1 is lost to follow-up at three months. Patients whose tumor markers return to normal after cis-platinum-based chemotherapy have a good long-term prognosis following radical surgery. If the tumor markers remain elevated, the prognosis is poor.
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