Biomedical subjects

A D Sutherland

Publications and source records attributed to A D Sutherland.

49 records · Page 3Linked to original sources

PubMed1986

Cardiovascular responses and lidocaine absorption in fiberoptic-assisted awake intubation.

Local anesthetic toxicity and cardiovascular stress during fiberoptic-assisted awake tracheal intubation were assessed prospectively in 20 patients with airway management problems. Cardiovascular responses, dose of lidocaine, its systemic absorption, and patient comfort were measured. A standardized topical anesthesia protocol of 4% lidocaine aerosol, topical 2% lidocaine viscous gel, and direct perbronchoscopic laryngeal application was used. Awake intubation produced no significant elevation of blood pressure or pulse rate either during the topical application or after the intubation. Despite a large total dose of topical lidocaine (5.3 +/- 2.1 mg/kg), the mean peak arterial plasma lidocaine concentration was low (0.6 +/- 2.1 micrograms/ml). Patient comfort assessment showed that nine patients had no discomfort, whereas 11 had minimal discomfort. Supplementary sedation used was minimal (fentanyl, 1.4 +/- 0.6 micrograms/kg, and diazepam, 1.9 +/- 1.8 mg). This method of producing topical anesthesia for awake tracheal intubation is recommended as a safe, easy, and comfortable method of managing patients with airway difficulties.

Absorption↗

PubMed1985

The role of H2 receptor antagonist premedication in pregnant day care patients.

In a randomised study of 132 pregnant outpatients, the effect on gastric volume and pH of oral premedication with a single dose of an H2 antagonist was investigated. Either cimetidine 400 mg (n = 33), or ranitidine 150 mg (n = 33), were given 90 to 120 minutes before scheduled surgery. Mean pH was significantly higher in cimetidine (5.0) and ranitidine (5.2) groups, and mean volume was significantly lower in cimetidine (13.2 ml) and ranitidine (11.1 ml) groups compared with 66 untreated patients (pH 1.6, volume 22.1 ml). A gastric pH less than or equal to 2.5 was found in 97 per cent of unpremedicated patients and 35 per cent of these patients also had a gastric volume greater than or equal to 25 ml. Eighty-three per cent of patients received their premedication within 75-200 minutes of surgery. Patients premedicated within that range had a significantly lower incidence of either a gastric pH less than or equal to 2.5 or a volume greater than or equal to 25 ml (p less than 0.01). Both cimetidine and ranitidine significantly reduced the number of patients with these risk factors. Four patients, however, in the cimetidine group had both a pH less than or equal to 2.5 and a volume greater than or equal to 25 ml. Pharmacological manipulation of the gastric environment does not prevent aspiration and clearly cannot be substituted for careful airway management and vigilance on the part of the anaesthetist. However, premedication of pregnant outpatients with a single, oral dose of an H2 antagonist is a simple, inexpensive, safe and effective way of reducing the risk of a severe aspiration pneumonitis.

Abortion, Therapeutic↗

PubMed1985

Lumbar extension in Duchenne muscular dystrophy: effect on lateral curvature.

The purpose of this study was to investigate the hypothesis that a lumbar pad producing extension of the lumbar spine is of value in posture support seats for children with Duchenne muscular dystrophy. Our method was to establish whether or not an increase in lumbar lordosis produced any increase in resistance to static lateral curvature of the supine lumbar spine. Nine boys with Duchenne muscular dystrophy were studied at an age when they were about to go into a wheelchair or had recently become wheelchair mobile. In each case the child lay supine on low-friction material on an x-ray table while the spine was flexed first to the right and then to the left, with and without a lumbar pad, by a predetermined force. The degree of lateral curvature was measured from anteroposterior radiographs. While lateral forces were applied when the boys were supine rather than seated, the results failed to show a difference in curvature with or without the lumbar pad.

Adolescent↗

PubMed1985

Effects of Pasteurella haemolytica cytotoxin on ovine peripheral blood leucocytes and lymphocytes obtained from gastric lymph.

Ovine peripheral blood leucocytes were separated on discontinuous Percoll density gradients into fractions rich in lymphocytes (PBLy) and polymorphonuclear leucocytes. Supernatant fluid from a dialysis sac culture of Pasteurella haemolytica biotype A serotype 1 (A1) was cytotoxic to these leucocytes in vitro. PBLy retained viability after storage in liquid nitrogen and could be employed in cytotoxicity assays. However, sheep cannulated via the common gastric lymph duct were an excellent source of large numbers of homogeneous lymphoid cells (GLy) which also stored well in liquid nitrogen. As both freshly collected and stored GLy were killed by culture supernatant fluid GLy offer advantages as target cells for further characterisation of the extracellular cytotoxin produced by P. haemolytica. From the results obtained, it is considered that all ovine leucocytes are susceptible to P. haemolytica cytotoxin.

Animals↗

PubMed1985

Patient comfort and plasma lignocaine concentrations during fibreoptic bronchoscopy.

In a preliminary prospective study, eleven outpatients undergoing fibreoptic bronchoscopy using a titrated dose of topical lignocaine anaesthesia were studied. Patient comfort, lignocaine dosage and resultant plasma concentrations were measured at four stages during the procedure. Large total doses, mean 512 (SD 55) mg lignocaine, were frequent and systemic absorption was unpredictable with two patients having plasma concentrations in the toxic range (greater than 5 micrograms/ml). Peak plasma concentrations, mean 2.3 (SD 1.4) micrograms/ml, occurred 30 to 40 minutes after commencement of topical application and coincided with completion of the procedure. No correlation was found between the individual dose of lignocaine administered and either the resultant plasma concentration or patient comfort scores. In an effort to minimise potential lignocaine toxicity, a fixed total dose technique (lignocaine 370 mg) was studied in a further twenty-one patients. No change in patient comfort scores and no toxic plasma concentrations were observed. Mean completion plasma concentration was 2.0 (SD 1.0) micrograms/ml. No clinical toxicity was observed in either group. Fibreoptic bronchoscopy in both groups using topical lignocaine anaesthesia without premedication or intravenous supplementation was well tolerated.

Administration, Oral↗

PubMed1984

Orthotic management of scoliosis in Duchenne muscular dystrophy.

This study investigates the effectiveness of spinal supports and seating systems in retarding the progress of spinal curvature in Duchenne muscular dystrophy. The approach was to take six monthly radiographs of children with this disease attending the Regency Park Centre sitting in their wheelchairs with their usual spinal supports. Scoliosis progressed from a mean value of approximately 10 degrees for children under 12 years to a value of the order of 75 degrees by the age of 16 to 18 years. The rate of progression peaked at an average of more than 1 degree per month between 14 and 18 years. The curvatures observed using modular seats, spinal jackets and custom-molded seats were not significantly different from those observed using unmodified wheelchair seats.

Adolescent↗

PubMed1983

Cytotoxic effect of Pasteurella haemolytica on ovine bronchoalveolar macrophages in vitro.

Live Pasteurella haemolytica A1 was shown to have a cytotoxic effect on suspensions of sheep bronchoalveolar macrophages. Cytotoxic activity was also demonstrable in bacteria-free supernatants from suspensions containing P. haemolytica. Heat-killed and ultra-violet killed organisms of P. haemolytica and live Staphylococcus aureus were not toxic to sheep BAM. These results suggest that a bacterial cell-free cytotoxin is produced by metabolically active P. haemolytica. Guinea-pig peritoneal macrophages, McCoy and pig kidney epithelial cell suspensions were unaffected by live P. haemolytica and supernatant from P. haemolytica cultures, indicating that the cytotoxin may only affect phagocytic cells of ovine or bovine origin.

Animals↗

PubMed1982

A comparison between innominate osteotomy and hip spica in the treatment of Legg-Perthes' disease.

Thirty-eight cases of Legg-Perthes' disease treated by innominate osteotomy have been reviewed and compared with 33 cases, matched for age and severity, treated in recumbency in plaster hip spicas. The results were similar in the two groups, the radiologic results in the innominate osteotomy group being marginally worse. There was a high incidence of poor results in both groups in those over the age of eight years at the onset of symptoms, especially if femoral "head at risk" signs were present. Other methods of treatment need to be provided for these older children.

Adolescent↗

PubMed1981

Modular seating for paralytic scoliosis: design and initial experience.

The conventional wheelchair sling seat provides little or no support to the spine of a child with myopathy or neurogenic muscular weakness. As the spinal muscles become weaker scoliosis may develop with associated deformity, pain and restriction of cardio-respiratory function. If muscle weakness is severe, the resultant fully developed deformity is virtually impossible to treat. Slowing the rate of increase of the deformity is, therefore, the most hopeful avenue of attack. This work addresses the hypothesis that custom moulded seating can increase sitting comfort and slow the rate of progression of spinal curvature in children with paralytic scoliosis, and further, that a range of standard or modular seats can achieve these goals at less cost. Previous work on this problem has ranged from simply padding the armrest, in order to distribute force over the rib cage, through to custom moulded seating. Our initial experience with custom moulding, using the bean bag evacuation and consolidation technique, produced several comfortable seats although the technique was labour intensive and therefore costly. This led us to attempt to develop a method of providing comfortable seating that would help control spinal deformity at reasonable cost. This paper describes the design of a standardized seating system for school age children with myopathy or neurogenic muscular weakness. Preliminary results indicate that this technique may have advantages over alternative methods of treatment. The radiological study is continuing.

Child↗

PubMed1980

The nuclide bone-scan in the diagnosis and management of Perthes' disease.

The nuclide bone-scan will reliably diagnose Perthes' disease with a sensitivity of 0.98 and a specificity of 0.95. The comparable figures for radiographic sensitivity and specificity are respectively 0.92 and 0.78. In addition, it is possible on the scan to recognise the onset of revascularisation of the femoral capital epiphysis some months before there are radiographic signs of new bone formation. Scintigraphy also suggests that in some cases of transient synovitis there may bae a period of reversible ischaemia of the capital epiphysis, which may have relevance to the pathogenesis of Perthes' disease.

Adolescent↗

PubMed1978

Reactivity of ovine lymphocytes to phytohaemagglutinin and pokeweed mitogen during pregnancy and in the immediate post-parturient period.

Lymphocytes from sheep in late pregnancy and at parturition showed markedly impaired proliferative responses to phytohaemagglutinin (PHA) in vitro when cultures were supplemented with foetal bovine serum (FBS), as compared to the responses of lymphocytes from non-pregnant sheep, sheep at 40 days of gestation and sheep at 80 days of gestation. Similar responses to PHA were observed when the medium was supplemented with autologous plasma (AP), although the responses were of a lower order. In both cases elevated responses to PHA were apparent at 10 days post-parturition. The response with FBS was more marked than with AP. Progressive reduction of lymphocyte responses to pokeweed mitogen (PWM) in the presence of FBS and AP were less obvious, although it was still apparent that responses to PWM were depressed at 120 days of gestation and at parturition, when compared with lymphocyte responses during early pregnancy (at 40 days and 80 days of gestation). The difference was much more apparent with AP than with FBS and responses during early pregnancy were markedly higher than those with FBS. An increase in lymphocyte responsiveness to PWM 10 days post-parturition was evident whether FBS or AP was incorporated in the cultures. The response with FBS was again more marked than with AP.

Animals↗

PubMed1975

Equinus deformity due to haemangioma of calf muscle.

Joint deformity secondary to extensive haemangiomatous involvement of the soft tissues has been well described and is easy to diagnose. If the haemangioma is small, localised and within the belly of a muscle the diagnosis is more difficult. In equinus deformity of obscure aetiology localised calf tenderness may be the only diagnostic sign. Three children with equinus deformity caused by a small haemangioma in the calf muscles were treated by simple excision with satisfactory results.

Child↗

PubMedDate not supplied

Spinal fusion in Duchenne's muscular dystrophy.

The Women's and Children's Hospital experience with Luque spinal fusion in Duchenne's muscular dystrophy was reviewed from its commencement in 1983 to the present with a view to assessing the clinical and radiologic outcome and safety of the procedure. Seventeen boys have undergone spinal fusion. L-rod instrumentation was used in 10, six of whom had significant problems with sitting imbalance or progression of the scoliosis or both. In seven cases, distal instrumentation was taken to the pelvis with a Galveston construct and rigid crosslinking. Apart from some progression and sitting imbalance in the L-rod group, there were few complications. In the Galveston group, pelvic obliquity was corrected by a mean of 63%, and there was better maintenance of correction. There were no pseudoarthroses or instrument failures in the Galveston group. Of the total group, four patients had forced vital capacity (FVC) values < 25% predicted, and two required ventilation postoperative (< 48 h). There were no other respiratory complications. The effect of surgery on respiratory function remains uncertain. Spinal fusion with the Luque rod construct and pelvic fixation is a safe procedure. It provided a mean correction of 60% and control of pelvic obliquity without significant postoperative deterioration. In our experience, surgery can be safely performed with FVC value down to 20% predicted. On the basis of these data, one current practice is to instrument to the pelvis with a Galveston construct and Texas Scottish Rite Hospital cross-linking.

Adolescent↗