Biomedical subjects
Publications and source records attributed to P Lesser.
A 30-gauge spinal needle was evaluated for Caesarean section, using a combined epidural/spinal technique, in 50 mothers. Spinal anaesthesia failed in six mothers and was inadequate in another six. General anaesthesia was required on one occasion. A 25% overall failure rate suggests that a 30-gauge needle is not a practical proposition for routine clinical practice.
The amount of larynx seen at intubation was assessed in 633 adult patients undergoing routine surgery. Various measurements of the head and neck were made in an attempt to discover which features were associated with difficulty with laryngoscopy (defined as the inability to see even the arytenoids). In addition 38 patients, reported by colleagues because they had been "difficult to intubate", were measured. Five useful risk factors, measured at three levels of severity, were identified. A simple predictive rule was developed and tested on a prospective set of 778 patients, in 1.5% of whom laryngoscopy was found to be difficult. Depending on the threshold chosen, the rule allowed the detection of, for example, 75% of the "difficult" laryngoscopies at a cost of falsely identifying 12% of the "not difficult" patients.
Saliva and plasma levels of phenytoin (DPH) and phenobarbital (PB) in a series of epileptic patients were compared by means of a radioimmunoassat (RIA) that required only 10 mul of saliva or plasma. There was an excellent linear relation (r = 0.98) between the logarithms of the concentrations of DPH in the two fluids. The ratio saliva/plasma was remarkably constant at 0.10 and was unaffected by varying levels of PB. The ratio was close to the fraction of DPH reported unbound in plasma at 37 degrees. PB plasma and saliva levels were also closely related (r = 0.98 for logarithm of plasma and saliva levels). This relation was nonlinear [plasma ocncentration = 4.43 X (salivary concentration)0.86], but could be approximated by the ratio plasma/saliva = 3.4. The simplicity of sample collection and the sensitivity of the RIA procedure suggest that clinical monitoring of these anticonvulsant levels may be carried out by RIA on saliva samples.
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