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Biomedical subjects

C W Pattison

Publications and source records attributed to C W Pattison.

At least 19 recordsLinked to original sources
PubMed1991

Development of an opiate-based anaesthetic technique for use in dogs with cardiomyopathy.

An opiate-based anaesthetic technique has been developed for use in dogs with end-stage heart failure due to dilated cardiomyopathy. It has been used in dogs undergoing translocation of the left latissimus dorsi around the descending thoracic aorta to create an autologous counterpulsation system. Anaesthesia was induced with barbiturate (10 mg/kg thiopentone) and fentanyl (500 micrograms) and maintained by an infusion of fentanyl (0.5 micrograms/kg/minute) [corrected] in addition to halothane (0.1 to 0.5 per cent) and nitrous oxide (20 to 60 per cent). This technique provided safe anaesthesia for major intrathoracic surgery.

Anesthesia, General↗
PubMed1991

Biochemical and structural adaptation of autologous skeletal muscle used for counterpulsation.

We have studied in a normal animal model (sheep), the biochemical and morphological adaptation of electrically stimulated skeletal muscle used for extra aortic counterpulsation. Immunocytochemical analysis of latissimus dorsi, using monoclonal antibodies to slow and fast myosin heavy chains, indicated an increase in the population of mixed fibres after stimulation for one week. By one month, up to 70% of fibres expressed both slow and fast myosin heavy chains in addition to the 15% of fibres expressing only slow myosin heavy chains. After 4 months, the population of mixed fibres was further transformed towards purely slow fibres to give values of 40 and 67% of fibres expressing only slow myosin heavy chain at 4 and 6 months, respectively. Increased staining, both in intensity and area, for NADH tetrazolium reductase activity (an enzyme of the oxidative metabolic pathway) was detected by 28 days. An increase in mitochondrial number was observed also by 28 days, further indicating a shift towards an oxidative metabolism. The molecular adaptation of latissimus dorsi was achieved by stimulation every fourth cardiac cycle at 35 Hz, 3 V, initiated 48 hours after the operation; this being a marked reduction in the delay from operation prior to stimulation. Evaluation of other regimes indicated that more frequent modes, or an increase in voltage or frequency, caused damage to the muscle during the early phase of molecular adaptation. A thorough understanding of the time sequence of the different adaptive processes is required to determine the ideal regime of stimulation initiated promptly after mobilisation of the muscle; aimed at harvesting the maximum amount of energy from the autologous muscle.

Adaptation, Physiological↗
PubMed1991

Development of mock circulation models for the assessment of counterpulsation systems.

STUDY OBJECTIVE: This study entailed the development of mock circulation models to assess and compare the haemodynamic efficacy of extra-aortic counterpulsation (using trained skeletal muscle wrapped around the proximal descending aorta) and conventional intra-aortic balloon counterpulsation. DESIGN AND EXPERIMENTAL MATERIALS: Hydraulic Windkessel type lumped parameter models were used either in conjunction with native skeletal muscle or as a dynamic simulation of counterpulsation. The haemodynamic performance of the wrapped latissimus dorsi muscle of the normal sheep was assessed using an artificial load to simulate the pressurised proximal descending aorta. Mock circulation models of counterpulsation comprised Windkessel compliance chambers, laminar flow resistors, a blood analogue, a prosthetic blood pump, and a purpose made hydraulic counterpulsator. MEASUREMENTS AND MAIN RESULTS: An electrically stimulated muscle wrap, 5 cm in length, previously trained for 2 weeks at 3 V and 35 Hz, was assessed for haemodynamic performance in a mock circulation: volume of fluid displaced = 14.1(SD 1.8) ml; pressure increase from 100 mm Hg = 14.9(2.1) mm Hg; external work per contraction cycle = 180(70)mJ; external mean power = 800(100) mW. In a simulation of intra-aortic balloon counterpulsation, haemodynamic benefit (ie, an increase in proximal flow rate and endocardial viability ratio and a reduction in left ventricular stroke power) was assessed with respect to defined parameters. CONCLUSIONS: This paper demonstrates the potential of the mock circulation models both for the investigation of muscle wrap performance and for the comparison of extra-aortic muscle with intra-aortic balloon counterpulsation.

Counterpulsation↗
PubMed1991

Persistent conduction disturbances following coronary artery bypass surgery: cold cardioplegic vs. intermittent ischaemic arrest (32 degrees C).

Two-hundred patients undergoing coronary artery bypass grafting were analysed to assess the incidence of new and persistent conduction disturbances in the postoperative period. Two groups, each of 100 patients, were studied. One group underwent surgery during cold crystalloid cardioplegic arrest with moderate whole-body hypothermia (28 degrees C). The second group was subjected to intermittent ischaemic arrest with mild whole-body hypothermia (32 degrees C). The incidence of postoperative conduction defects was significantly higher in the cardioplegic group.

Arrhythmias, Cardiac↗
PubMed1991

Aortic counterpulsation for up to 28 days with autologous latissimus dorsi in sheep.

This article reports the development and assessment of an entirely autologous extraaortic counterpulsation system using skeletal muscle (latissimus dorsi). The technique has been performed and assessed in 16 sheep to quantify the effectiveness of counterpulsation over periods up to 28 days and to optimize the stimulation regimens for muscle contraction and fiber-type transformation. Hemodynamic changes have been quantified by calculation of the endocardial viability ratio. This has shown an increase of between 12% and 89% for 28 days. The wide variety of increase observed has been related to the development of an optimum flap configuration. The technique of surface impedance monitoring of flap blood flow has allowed the start of electrical stimulation after 48 hours with the introduction of hemodynamic benefit (1:4 mode) during the process of fiber-type transformation (in situ training). Extraaortic counterpulsation with autologous latissimus dorsi has been shown to be effective and safe for as long as 28 days. It has not been associated with any thromboembolic or infective complications, which we attribute to the exclusion of any foreign material in the design.

Animals↗
PubMed1990

Palliative intubation of malignant oesophageal strictures.

A 6-year experience (1981-1987) of palliative intubation of irresectable malignant oesophageal strictures is reported in 110 patients with a mean age of 70.3 (range 41-90) years. Pulsion intubation was performed on 71 patients, 11 (15.5%) of whom died, and traction intubation on 39 with 6 (15.4%) deaths. Seven deaths resulted from instrumental perforation, but six other patients survived perforation and left the hospital in satisfactory condition. Mean in-patient stay was 8 (range 1-26) days. Non-fatal tube-related complications were more common in pulsion intubation, but was found to be highly effective in relieving dysphagia, with shortened hospital stay (mean 6 days) and acceptable morbidity and mortality rates. These results indicate the trend towards, and the increased safety of, pulsion intubation.

Aged↗
PubMed1989

Variable adaptation of molecular mechanisms in relation to the use of autologous striated muscle to augment myocardial function.

Significant recent advances in molecular biology and protein biochemistry have allowed the examination of muscle function at gene and protein level. This article reviews the variable adaptation of molecular mechanisms in striated muscle. The adaptation and transformation of fast skeletal muscle in response to chronic electrical stimulation may have considerable importance in relation to the use of autologous skeletal muscle to augment myocardial function.

Adaptation, Biological↗
PubMed1989

Mediastinoscopy in the investigation of primary mediastinal lymphadenopathy.

Mediastinoscopy was introduced by Carlens (1) in 1959 to obtain lymph node biopsies from the superior mediastinum in patients with bronchogenic carcinoma. The technique has been widely accepted for clinical staging as a guide to operability and prognosis. We report on a consecutive retrospective series of 110 patients undergoing mediastinoscopy between 1982-1986 for primary mediastinal lymphadenopathy in order to assess the diagnostic value and safety of the procedure. Mediastinoscopy gave a positive histological diagnosis in 74.5% of cases with no false negative results. There were no deaths and one complication only (pneumothorax). This study shows mediastinoscopy to be a safe, accurate and cost effective procedure minimising hospital stay and allowing appropriate treatment to be immediately commenced upon diagnosis. Mediastinoscopy obviates the need for expensive computed tomography or nuclear magnetic resonance scans and we conclude that it is the investigation of choice for primary mediastinal lymphadenopathy after confirmation by plain chest radiography.

Adult↗
PubMed1988

Hidden foreign body as a cause of recurrent hemoptysis in a teenage girl.

Hemoptysis in a teenage girl caused by a foreign body located in the posterior segment of the left lower lobe is described. The patient was seen four years after the initial inhalation. The importance of taking a meticulous history and the use of computed tomography in the localization of the lesion are emphasized, and the use of the fiberoptic bronchoscope in peripheral lesions and in the investigation of hemoptysis is discussed.

Adolescent↗
PubMed1988

Splenic herniation. Case report.

A case of splenic herniation complicated by spurious hypertension is described. A misleading provisional diagnosis was made despite computerised tomography (CT Scan). Diaphragmatic herniation is discussed and the use of computerised tomography in the diagnosis of masses arising from the posterior aspect of the diaphragm is emphasized.

Adult↗
PubMed1984

Oesteoarticular tuberculosis--an unusual presentation.

A patient presented with pain in the wrist and neck and X-rays showed destructive lesions of several carpal bones and cervical vertebrae. The carpal lesion was explored surgically and found to be tuberculous. Chemotherapy resulted in healing at both sites of disease.

Aged↗
PubMed1984

Oesophageal obstruction due to saccular aneurysm of the distal thoracic aorta.

The second reported case and first successful treatment of oesophageal obstruction due to a saccular aneurysm of the distal thoracic aorta is described. The patient, a 69-year-old male, presented with severe dysphagia which was thought to be due either to achalasia or a tumour. Operation, however, revealed a large aneurysm at the level of the diaphragmatic hiatus which was compressing the oesophagus against the right crus. As the anatomy of the aneurysm was unknown and there was a significant risk of damage to the spinal arteries the oesophageal obstruction was treated by transposition of the oesophagus combined with an anti-reflux repair. This has given an excellent clinical result and the aneurysm has remained unchanged over a period of eighteen months.

Aged↗
PubMed1984

Surgical treatment of hydrothorax complicating continuous ambulatory peritoneal dialysis.

Acute hydrothorax is a well recognized complication of continuous ambulatory peritoneal dialysis (CAPD) and is usually regarded as a contra-indication to the further use of this form of dialysis. We report the first case of treatment by surgical closure of a communication between the peritoneal and the right pleural cavity enabling CAPD to continue successfully. The development of an acute hydrothorax on CAPD is therefore not a reason to abandon this form of dialysis and can be treated by a simple thoracic surgical procedure.

Aged↗