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Biomedical subjects

R W Walker

Publications and source records attributed to R W Walker.

At least 19 recordsLinked to original sources
PubMed2000

The laryngeal mask airway in the difficult paediatric airway: an assessment of positioning and use in fibreoptic intubation.

The laryngeal mask airway (LMA) was used in 34 children who presented with difficult airways and difficulty in intubation. All 34 children were a grade 3 or grade 4 Cormack and Leehane view at conventional laryngoscopy. The laryngeal mask airway was used as part of the anaesthetic technique. It was either used as the method of airway maintenance during a short procedure or as an aid to fibreoptic intubation. The results of its use in this group of patients showed that overall a good airway was obtained in 73% of patients and an adequate airway in 27%, and in no patient was a poor airway obtained. The fibreoptic positioning of the LMA, taken from the distal aperture of the laryngeal mask airway showed that, overall, in 29.5% of patients a full view of the glottis (grade 1) was obtained, in 29.5% of patients a partial view of the glottis (grade 2) was obtained and in 41% a view of the epiglottis only (grade 3) was obtained. In no patient was a view excluding the epiglottis obtained. In children with a mucopolysaccharide disorder, the number of children who had a grade 3 view increased to 54%. Children with a disorder other than mucopolysaccharidosis had a grade 3 view in only 17% of cases. Children with mucopolysaccharidoses had a grade 1 view in only 14% of cases compared with 58% in the group with other disorders. Of the 34 patients, 21 patients were intubated on 31 separate occasions. There were no failures. The complications of the fibreoptic intubation technique described are outlined.

Anesthesia, Endotracheal↗
PubMed1999

A bronchogenic cyst in an infant causing tracheal occlusion and cardiac arrest.

A 3-month-old infant treated for 3 weeks for suspected bronchiolitis, developed episodes of profound desaturation. A lateral X-ray showed displacement and compression of the trachea. Respiratory arrest, from which she was successfully resuscitated, occurred just before MRI scan. The mass was removed at thoracotomy and a histological diagnosis of a bronchogenic cyst was made. Mediastinal masses in babies are relatively rare, and the situation in which they present with acute respiratory distress may prove extremely challenging to the anaesthetist. Bronchogenic cysts are difficult to diagnose pre-operatively and awareness may assist in the peri-operative management of these infants.

Anesthesia, General↗
PubMed1999

Tears at bedtime.

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Acetaminophen↗
PubMed1998

Long QT syndrome.

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Anesthesia↗
PubMed1997

Dementia with lewy bodies: a study of post-synaptic dopaminergic receptors with iodine-123 iodobenzamide single-photon emission tomography.

Dementia with Lewy bodies (DLB) can at present only be diagnosed with certainty by neuropathological examination. Diagnosis during life remains at best probable, based on the presence of symptoms known from autopsy studies to be frequently associated with DLB. The greatest practical clinical problem lies in distinguishing DLB and Alzheimer's disease (AD). In DLB there is a considerable degeneration of nigral neurones with depletion of striatal dopamine. In contrast, AD is not associated with significant changes in dopamine metabolism. Iodine-123 iodobenzamide single-photon emission tomography (IBZM-SPET) measures post-synaptic dopamine D2 neuroreceptor availability in the corpus striatum, but is nevertheless a method for assessing the integrity of the nigrostriatal dopaminergic pathway. Sixteen clinically diagnosed DLB patients, 15 normal controls and 13 AD patients underwent IBZM-SPET. All subjects were scanned 1.5-2 h after intravenous injection of 185 MBq of 123I-IBZM. Circular regions of interest were employed to calculate radioactivity ratios in each hemisphere as follows: caudate nucleus/frontal cortex, putamen/frontal cortex and caudate nucleus/putamen. The DLB patients had significantly lower left caudate/putamen ratios (95% confidence intervals: DLB 0.893-0.965, AD 0.972-1.175, controls 1.031-1.168) than either controls or AD patients, and significantly lower right caudate/putamen ratios (95% confidence intervals: DLB 0.926-1.019, AD 0.954-1.103, controls 1. 027-1.144) than controls. Our data suggest that patients with DLB diagnosed by clinical criteria have changes in striatal post-synaptic D2 receptors. This may be of value in distinguishing DLB from AD during life.

Aged↗
PubMed1997

A fibreoptic intubation technique for children with mucopolysaccharidoses using the laryngeal mask airway.

Children with mucopolysaccharidoses present the anaesthetist with both a difficult airway and often an impossible intubation using conventional techniques. A technique for airway management and tracheal intubation is described utilizing the Brain laryngeal mask airway, the fibreoptic bronchoscope, a guide wire and a ureteral dilator. Two case reports of children with mucopolysaccharidoses are presented who were managed successfully with this technique. The advantages of the technique are discussed.

Adolescent↗
PubMed1997

Blood loss during primary total hip arthroplasty: use of preoperative measurements to predict the need for transfusion.

The blood loss resulting from total hip arthroplasty was studied in 53 patients. Calculated blood loss exceeded measured blood loss in all cases. The most significant predictor of postoperative packed-cell volume (PCV) was the preoperative PCV. In a further 37 patients the preoperative PCV was used successfully to predict the postoperative PCV and the need for transfusion.

Arthroplasty, Replacement, Hip↗
PubMed1996

Quantity and distribution of Malassezia organisms on the skin of clinically normal dogs.

OBJECTIVE: To define the extent to which Malassezia organisms can be recovered from the skin of clinically normal dogs and to assess differences in organism recovery related to anatomic sampling site and to method of collection. DESIGN: Prospective, controlled study. ANIMALS: 19 clinically normal dogs. PROCEDURE: The number of Malassezia pachydermatis organisms were determined in fungal cultures of samples obtained from the skin of clinically normal dogs, using an adhesive tape method to obtain samples from 10 sites/dog. Additionally, 3 methods (direct impression, swabbing technique, and superficial skin scraping) that are commonly used for obtaining samples for cytologic examination were evaluated. RESULTS: Malassezia organisms were found in low numbers as part of the microflora of the skin of clinically normal dogs. Number of organisms differed significantly for various anatomic locations (chin, highest number; inguinal and axillary regions, lowest number). Malassezia organisms were identified more frequently by use of adhesive tape and fungal culturing than by the methods used for cytologic examination. However, comparing methods used for obtaining samples for cytologic examination with each other, marked differences were not detected in our ability to recover yeast organisms among the 3 techniques. CLINICAL IMPLICATIONS: Although Malassezia spp is part of the microflora of the skin of clinically normal dogs, it is extremely difficult to detect the organism by any of the 3 sampling methods used for sample collection for cytologic examination. Therefore, anatomic site and method of sample collection should be considered when attempting to make a diagnosis of Malassezia dermatitis.

Animals↗
PubMed1996

Anaesthesia for Rett syndrome.

Rett syndrome is a devastatingly disabling neurological disease that is only observed in girls. Scoliosis occurs in roughly half the girls and surgery may be required. Anaesthesia is described in three patients. Sudden death may be a feature of the disease which occurred four weeks postoperatively in one case. Although a long QTc interval may be seen, it did not occur in any of our cases.

Adolescent↗
PubMed1996

Chemotherapy without irradiation--a novel approach for newly diagnosed CNS germ cell tumors: results of an international cooperative trial. The First International Central Nervous System Germ Cell Tumor Study.

PURPOSE: Radiation therapy for CNS germ cell tumors (GCT) is commonly associated with neurologic sequelae. We designed a therapeutic trial to determine whether irradiation could be avoided. PATIENTS AND METHODS: Patients received four cycles of carboplatin, etoposide, and bleomycin. Those with a complete response (CR) received two further cycles; others received two cycles intensified by cyclophosphamide. RESULTS: Seventy-one patients were enrolled (45 with germinoma and 26 with nongerminomatous GCT [NGGCT]). Sixty-eight were assessable for response. Thirty-nine of 68 (57%) achieved a CR within four cycles. Of 29 patients with less than a CR, 16 achieved CR with intensified chemotherapy or second surgery. Overall, 55 of 71 (78%) achieved a CR without irradiation. The CR rate was 84% for germinomas and 78% for NGGCT. With a median follow-up duration of 31 months, 28 of 71 patients were alive without relapse or progression. Thirty-five showed tumor recurrence (n = 28) or progression (n = 7) at a median of 13 months. Twenty-six of 28 patients (93%) who recurred following remission underwent successful salvage therapy. Pathology was the only variable predictive of survival. The probability of surviving 2 years was .84 for germinoma patients and .62 for NGGCT. Seven of 71 patients died of toxicity associated with study chemotherapy. CONCLUSION: Forty-one percent of surviving patients and 50% of all patients were treated successfully with chemotherapy only without irradiation. Chemotherapy-only regimens for CNS GCT, although encouraging, should continue to be used only in the setting of formal clinical trials.

Adolescent↗
PubMed1995

A clinical and molecular genetic study of dentatorubropallidoluysian atrophy in four European families.

Dentatorubropallidoluysian atrophy is a neurodegenerative disorder with characteristic pathology, chiefly described in reports from Japan, and is associated with an unstable CAG trinucleotide repeat in a gene on chromosome 12. We describe four European families, three British and one Maltese, with this mutation. All exhibited autosomal dominant inheritance, and there was evidence for anticipation associated with an increase of the expansion with paternal transmission in two families. Affected chromosomes from patients with dentatorubropallidoluysian atrophy had CAG expansions of 58 to 74 repeats, compared to 7 to 26 in control chromosomes, and the size of repeat was significantly inversely correlated with age of onset. The clinical features were diverse, even within individual families, and comprised a combination of a movement disorder (chorea, myoclonus, dystonia, or parkinsonism), cerebellar ataxia, epilepsy, psychosis, and dementia. A clinical diagnosis of Huntington's disease had been made in affected individuals from all families. Neuropathological examination of 2 patients showed no specific abnormality in one and degenerative changes predominantly affecting the spinal cord in the other. Investigation of 55 patients who might represent sporadic examples of dentatorubropallidoluysian atrophy did not detect any expanded alleles. Dentatorubropallidoluysian atrophy is likely to be more common than previously recognized in non-Japanese populations, and should be considered in any patient with a dominantly inherited neurodegenerative disorder with the above-mentioned clinical features.

Adolescent↗