PubMed Health⌕ Search

Biomedical subjects

J H MacG Palmer

Publications and source records attributed to J H MacG Palmer.

3 recordsLinked to original sources
PubMed2000

The effect of cricoid pressure on the cricoid cartilage and vocal cords: an endoscopic study in anaesthetised patients.

Cricoid pressure is used to protect the lungs from contamination with gastric contents during tracheal intubation. We studied the effect of cricoid pressure applied with a yoke on 30 anaesthetised patients examined fibreoptically through a laryngeal mask airway. We assessed the effect of 20, 30 and 44 N on the internal appearance of the cricoid and vocal cords. Difficulty in ventilation was also recorded. At 44 N, cricoid deformation occurred in 27/30 patients (90%) and 15/30 (50%) had cricoid occlusion [13/30 (43%) had cricoid occlusion at 30 N and 7/30 (23%) at 20 N]. Associated difficulty in ventilation was present in 15 patients (50%) and 18/30 (60%) had vocal cord closure with associated difficult ventilation, at forces up to 44 N. Cricoid occlusion was unrelated to age and body mass index but females were at greater risk. Orthodox values of cricoid pressure, applied with a yoke, may produce obstruction at the level of the cricoid cartilage or vocal cords, with implications for tracheal intubation and ventilation by mask.

Adult↗
PubMed2000

An assessment of the thermal safety of microwave warming of crystalloid fluids.

We performed an in vitro study to determine the thermal safety of a domestic microwave to warm intravenous crystalloid solutions. Five-hundred-millilitre bags of crystalloid, randomly allocated to groups which differed in power setting, timer setting and whether or not agitation was performed after warming, were heated in a microwave oven to a calculated temperature of 39 degrees C. Timer accuracy was checked by stopwatch. Bag temperature was measured using an infrared tympanic temperature probe and fluid temperature was measured with an in-line thermocouple. Mean times measured by stopwatch were higher than set. No in-line temperatures reached 40 degrees C. Wider overall ranges and a higher mean were found with the tympanic probe compared with in-line temperature measurement. There were significant differences between the in-line temperatures of shaken and unshaken bags at each power setting, but not when groups were added together. There was no change in colour or odour of bags or fluid. One bag developed a pinhole leak when the packaging was removed.

Anesthesia↗