PubMed Health⌕ Search

Biomedical subjects

K MacGee

Publications and source records attributed to K MacGee.

4 recordsLinked to original sources

The use of midazolam in diagnostic and short surgical procedures in children.

A new technique of sedation for children is described, in which midazolam (0.2 mg.kg-1) was administered topically by the nasal route, followed by ketamine (9.0 mg.kg-1) administered rectally in 32 patients breathing air spontaneously. Sedation was good in 23, seven required further ketamine (1.0 mg.kg-1 i.v.), and in two, halothane was introduced. There was no evidence of severe respiratory depression except during oesophagoscopy. Cardiovascular stability was excellent. Of 21 patients over 5 years old, 19 developed complete and two partial anterograde amnesia for the administration of ketamine and surgery. The major complications were nausea and vomiting (five patients) and salivation (eight patients). The mean recovery time was 40 min (s.d. 33 min). It provided a relatively safe, adaptable, non-invasive method of inducing sedation in children.

Administration, Intranasal↗

Respiratory effects of nitrous oxide during isoflurane anaesthesia in children.

Respiratory effects of nitrous oxide and isoflurane were studied in 13 children (mean age 45.6 +/- 19.3 months, mean weight 14.9 +/- 4.8 kg) during surgery under continuous extradural anaesthesia. Three different anaesthetic states were studied: isoflurane 0.5 MAC in oxygen (27 study periods), isoflurane 0.5 MAC with 50% nitrous oxide (32), isoflurane 1 MAC in oxygen (25). End-tidal carbon dioxide (PE' CO2) and isoflurane, respiratory indices (tidal volume, VT; minute ventilation, VE; mean inspiratory flow, VI; respiratory frequency f, effective inspiratory timing TI/Ttot were measured. The addition of nitrous oxide (comparison of respiratory variables obtained in 25 successive periods at (1) and (2)) produced a significant increase in PE' CO2' significant decreases in VT, VE and VI, a significant increase in f. The increase in alveolar concentration of isoflurane ((1) compared with (3) in 25 successive periods) was associated with a significant increase in PE' CO2' significant decreases in VT, VE, VI and a significant increase in f. The equipotent anaesthetic states (2) and (3) were compared in 21 successive periods. In children, the net result of substituting nitrous oxide for an equal MAC fraction of isoflurane was to produce a smaller decrease in VT responsible for a smaller decrease in VE without significant change in respiratory rate.

Anesthesia, Inhalation↗

Changes in ventilatory patterns during halothane anaesthesia in children.

Changes in ventilatory variables (VE, VE, f, Tl/Ttot, VT/Tl, PE'CO2) were studied in 12 unpremedicated children, weighing between 10 and 20 kg, during halothane anaesthesia. At an inspired concentration of 0.5% halothane, respiratory rate increased, VT decreased, and VE did not change markedly. When the inspired halothane concentration increased further, there was a significant decrease in VE, mainly as a result of a marked decrease in VT. PE'CO2 increased significantly and inspiratory duty cycle decreased at high inspired halothane concentrations. On return to baseline (0.5% halothane), there was a significant decrease in inspiratory timing and a significant increase in PE'CO2. The relations between these changes and the effect of halothane on inspiratory muscles are discussed.

Anesthesia, Inhalation↗