Apnoeic oxygenation in adults under general anaesthesia using Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) - a physiological study.

BACKGROUND.: Apnoeic oxygenation during anaesthesia has traditionally been limited by the rapid increase in carbon dioxide and subsequent decrease in pH. Using a Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) technique a slower increase in carbon dioxide than earlier studies was seen. Notably, apnoeic oxygenation using THRIVE has not been systematically evaluated with arterial blood gases or in patients undergoing laryngeal surgery. The primary aim of this study was to characterize changes in arterial P O 2 , P CO 2 and pH during apnoeic oxygenation using THRIVE under general anaesthesia. METHODS.: Adult patients, (ASA I-II), undergoing shorter laryngeal surgery under general anaesthesia, were oxygenated during apnoea using THRIVE, 100% oxygen, 40-70 litres min - 1 . A cohort was randomized to hyperventilate during pre-oxygenation. Vital parameters and blood gases were monitored. RESULTS.: Thirty-one patients, age 51 (34-76) yr, BMI 25 (4) were included. Mean apnoea time was 22.5 (4.5) min. Patients were well oxygenated, S pO 2 was never below 91%. The increase in P aCO 2 and end-tidal CO 2 during apnoea was 0.24 (0.05) and 0.12 (0.04) kPa min -1 , respectively. Hyperventilation during pre-oxygenation generated no difference in P aCO 2 at the end of apnoea compared with normoventilation. CONCLUSIONS.: This physiological study of apnoeic oxygenation using THRIVE during laryngeal surgery shows that this technique is able to keep patients with mild systemic disease and a BMI <30 well oxygenated for a period of up to 30 min. The THRIVE concept makes it possible to extend the apnoeic window but monitoring of CO 2 and/or pH is recommended. CLINICAL TRIAL REGISTRATION.: NCT02706431.

Topical sodium cromoglycate in atopic dermatitis. A disappointing but informative trial.

Forty children with atopic eczema requiring topical steroids entered a double-blind group comparative study over 12 weeks and were randomized to either 4% sodium cromoglycate (SCG) in an oil-in-water cream or matching placebo cream. The eczema was evaluated on area charts for 20 parts of the body at five clinic visits. In addition, the families kept diaries on symptoms and treatment. After 3 weeks there were small but statistically significant decreases in severity scores recorded at the clinical visits in the SCG group compared with small increases in the placebo group. However, there were no statistically significant differences in the diary card data during the first 3 weeks of treatment or in any other period, nor were significant differences found in any efficacy data collected during the other 9 weeks of the trial. There were no marked differences in treatment opinions, unusual symptoms, skin infections, use of topical steroids or drugs, or acceptability data between the groups. Staphylococcus aureus was found once or twice in cultures from eczema lesions in 31 of 40 children with no marked group difference. The trial showed that there is great need for improved information, family support and topical as well as general treatment in childhood atopic eczema, but topical SCG did not relieve the patients' eczema.