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Biomedical subjects

P Charters

Publications and source records attributed to P Charters.

29 records · Page 2Linked to original sources
PubMed1990

Factor analysis in patients with a history of failed tracheal intubation during pregnancy.

Eight patients with a history of failed tracheal intubation during pregnancy were investigated by x-ray laryngoscopy after delivery. Partial elevation of the epiglottis with no view of glottic structures was found in five patients who were therefore considered to still present difficulty. In each of these five patients the blade tip failed to make contact with the hyoid and in four this was explained by the tongue being compressed into a pear shape such that it prevented sight of the larynx. Relatively few abnormal anatomical indices were seen in these patients and this was in keeping with the level of difficulty encountered. An angular measure of jaw protrusion from a line joining the upper incisors and a point just above and anterior to the vocal cords, to the mid-point on the inner surface of the mandible was useful: the lower angle of this triangle was as important as the angle at the incisors.

Adult↗
PubMed1989

Defining a standard intubating position using "angle finder".

Study of patients who exhibit only limited morphological abnormality yet present difficulty with direct laryngoscopy is facilitated by a standard intubating position. The "Angle Finder" instrument allows implementation of a simple reproducible geometric standard which is applied easily in formal research work and in clinical practice and teaching. The proposed standard relates to the curved (Macintosh) laryngoscope blade and a supine patient. The lower neck flexion is 35 degrees and extension of the plane of the face 15 degrees, each angle measured relative to horizontal. Initially, the standard was derived from a review of the literature, then validated in a study of the intubating practices of 10 senior anaesthetists. A more detailed study of 10 normal volunteers confirmed reproducibility and, for nine patients with a history of difficult direct laryngoscopy, the standard was shown to be appropriate.

Head↗
PubMed1989

Disposition of cervical vertebrae, atlanto-axial joint, hyoid and mandible during x-ray laryngoscopy.

Ten healthy volunteers underwent direct laryngoscopy using topical anaesthesia and a curved Macintosh laryngoscope blade. A lateral x-ray was performed during laryngoscopy in a standard intubating position. In this position the lower neck was relatively straight and increasing curvature occurred from the mid cervical spine upwards. Extension at the atlanto-axial joint was probably near maximum; this has implications for conditions associated with laxity of this joint. The position of the mandible was influenced by the direction of pull on the laryngoscope handle. The hyoid was drawn forward and its body tilted downwards so as to lie halfway between the lower border of the mandible and the glottis. The relative length of epiglottis projecting above the hyoid was variable.

Adult↗
PubMed1988

An additional tactile test. Further developments in tactile tests to confirm laryngeal placement of tracheal tubes.

An additional clinical test to confirm laryngeal placement of tracheal tubes is described. Using the new test, placement was confirmed in all of 50 patients studied in whom difficulty would have been anticipated using previously described tactile tests (male patients with lower molar teeth). Two anaesthetists with small hands averaged 98% confirmations in two series each of 100 consecutive unselected intubations. A simple modification of the tests enables their application after nasotracheal intubation; even with small hands, a confirmation rate of 96% in 50 consecutive cases was found. The three tactile tests are reviewed and analysed. In the authors' combined experience of 14 cases of difficult laryngoscopy the tests gave reliable confirmation in 12 patients. Familiarity with these tests is stressed to be important for their reliable implementation.

Adult↗
PubMed1987

Tactile orotracheal tube placement test. A bimanual tactile examination of the positioned orotracheal tube to confirm laryngeal placement.

The development of a tactile clinical test of the positioned orotracheal tube is described which allows confirmation of its location within the larynx. It was possible, after preliminary experience with the test, to confirm laryngeal placement confidently in an average of 97% of cases in two concurrent series each of which consisted of 100 patients. Inevitably, there are limitations to its usefulness but it has the advantage that no special apparatus is required for its performance. The implications of this test are discussed in relation to difficult intubation, obstetric anaesthesia, the teaching of applied anatomy and checking by their trainers of intubations performed by very junior anaesthetists. Familiarity with this test should be considered essential for its reliable implementation.

Adult↗
PubMed1983

Mannitol, osmolality and steroids during renal transplantation. Real and theoretical influences on plasma potassium.

Mannitol did not have an exaggerated effect on plasma potassium when administered to twelve patients undergoing renal transplantation. Unexpected rises in plasma osmolality, greater than those recorded after mannitol, were observed in two of the patients. In these two patients the osmolality changes were due to sudden hyperglycaemia and followed methylprednisolone therapy (given for immunosuppression). It is suggested that under certain circumstances, such changes in osmolality may lead to a rise in plasma potassium comparable to the effect of mannitol. One of the two patients with the rise in glucose and osmolality did have a rise in plasma potassium.

Blood Glucose↗
PubMed1981

Renal transplantation in diabetes mellitus.

Renal failure is common in patients with diabetes mellitus, and renal transplantation has been used in its treatment. There are indications that the operation may be hazardous in these circumstances, and a report is presented in which careful biochemical monitoring of a diabetic patient undergoing transplantation revealed two episodes of hyperkalaemia which might go some way to explain the hazards of this operation. The relevance of the concept of glucose-induced hyperkalaemia is discussed and it is suggested that intravenous infusion of insulin during and after operation might have decreased the rises in serum potassium. The report emphasises the need for careful biochemical monitoring of diabetics undergoing renal transplantation.

Adult↗