This prospective, randomized, study was designed to compare the effect of two different preloading volumes of Ringer's lactate for prevention of maternal hypotension induced by spinal anaesthesia for Caesarean section. Eighty ASA I or II obstetric patients were randomized to two groups. Group 1 (n = 40) received 20 ml/kg of Ringer's lactate and Group 2 (n = 40) 10 ml/kg of Ringer's lactate over 20 minutes before spinal anaesthesia. The lowest mean arterial pressure (MAP) for both groups were recorded at 15 minutes after giving spinal anaesthesia, This difference in the drop of MAP from base-line at 15 minutes (mean decrease of 12.5 mmHg from baseline), between preloading with 10 ml/kg and 20 ml/kg of Ringer's was statistically significant. Twelve patients from Group 1 required bolus doses of ephedrine and 15% of these needed additional crystalloid whereas two patients from Group 2 needed ephedrine boluses and 22% of these required additional crystalloid. The difference in frequency of requirement for treatment of hypotension was not statistically significant. There were five patients in Group 1 and six patients in Group 2 who experienced nausea and vomiting, the frequency of occurrence did not show any statistically significant difference between the two groups. In conclusion, for prevention of hypotension during spinal anaesthesia for Caesarean section, infusing 20 ml/kg or 10 ml/kg of Ringer's Lactate gave similar results and we do not recommend the use of a larger volume of crystalloid for preloading before spinal anaesthesia.
Airway inflammation can be demonstrated by the modem method of sputum induction using ultrasonic nebulizer and hypertonic saline. We studied whether compressed-air nebulizer and isotonic saline which are commonly available and cost less, are as effective in inducing sputum in normal adult subjects as the above mentioned tools. Sixteen subjects underwent weekly sputum induction in the following manner: ultrasonic nebulizer (Medix Sonix 2000, Clement Clarke, UK) using hypertonic saline, ultrasonic nebulizer using isotonic saline, compressed-air nebulizer (BestNeb, Taiwan) using hypertonic saline, and compressed-air nebulizer using isotonic saline. Overall, the use of an ultrasonic nebulizer and hypertonic saline yielded significantly higher total sputum cell counts and a higher percentage of cell viability than compressed-air nebulizers and isotonic saline. With the latter, there was a trend towards squamous cell contaminations. The proportion of various sputum cell types was not significantly different between the groups, and the reproducibility in sputum macrophages and neutrophils was high (Intraclass correlation coefficient, r [95%CI]: 0.65 [0.30-0.91] and 0.58 [0.22-0.89], p < 0.001). Overall changes in median FEV, were small and comparable between all groups. Induction using ultrasonic nebulizers together with hypertonic saline was generally less well tolerated than compressed-air nebulizers and isotonic saline. We conclude that in normal subjects, although both nebulizers and saline types can induce sputum with reproducible cellular profile, ultrasonic nebulizers and hypertonic saline are more effective but less well tolerated.