A clinical determination of optimal fresh gas flow in a baby EAR circuit
Theerapongpakdee, S.; Phanpanusit, T.; Horatanaruang, D.; Bunsangjaroen, P.; Limpkulwathanaporn, P.; Thananun, M.; Nonlhaopol, D.
Journal of the Medical Association of Thailand 92(5): 667-671
2009
ISSN/ISBN: 0125-2208 PMID: 19459529 Document Number: 10467
Baby EAR circuit is a new modified enclosed afferent reservoir anesthetic breathing system for pediatric patients. By following His Majesty the King of Thailand's self-sufficiency philosophy, the circuit is simple and made of low-cost and easy-to-find materials found in the operating room. This present study was to investigate clinical use of the circuit and to find the optimal fresh gas flow in clinical setting. A prospective descriptive study was conducted in pediatric patients, weighed 5-20 kg, anesthetized for surgery. The Baby EAR breathing circuit was used for general anesthesia with endotracheal tube and control ventilation. Different fresh gas flow of 3, 2.5, 2 and 1.5 liter per minute (LPM) was used consecutively. The authors recorded end-tidal carbon dioxide (EtCO2) and mean inspiratory carbon dioxide (ImCO2) while using fresh gas flow at 3, 2.5, 2, and 1.5 LPM. EtCO2 of 35-45 mmHg and ImCO2 of < 6 mmHg were considered clinically acceptable. Fifty patients were enrolled. Mean value (95% CI) of EtCO2 at fresh gas flow rate of 1.5, 2, 2.5, and 3 LPM were 39.6 (39.2, 40.9), 36.7 (35.5, 37.8), 35.4 (34.3, 36.4), and 35.4 (34.3, 36.4) mmHg respectively. Mean value (95% CI) of ImCO2 at fresh gas flow rate of 1.5, 2, 2.5, and 3 LPM were 4.0 (3.0, 4.9), 2.4 (1.7, 3.0), 1.8 (0.9, 2.6), and 1.3 (0.9, 1.7) mmHg respectively. Percentage of patients (95% CI) who had clinically acceptable EtCO2 and ImCO2 at fresh gas flow rate of 1.5, 2, 2.5, and 3 LPM were 70% (56.2, 80.9), 92% (81.2, 96.8), 98% (89.5, 99.6), and 100% (92.9, 100) respectively. No patients had serious complications. Baby EAR circuit can be made economically and used safely for general anesthesia with control ventilation in pediatric patients weighing 5 to 20 kg at optimal fresh gas flow of 3 LPM.
Document emailed within 1 workday
