Assessment of spontaneous ventilation in anesthetized children with use of a pediatric circle or a Jackson-Rees system.
To compare respiratory workloads, inspiratory efforts were evaluated in 11 children anesthetized with halothane while breathing through a pediatric circle or a Jackson-Rees system. All underwent urogenital surgery and received caudal analgesia after tracheal intubation. Anesthesia was maintained with O2/air at an end-tidal halothane concentration of 0.8%. A pediatric circle system at a fresh gas flow (FGF) of 0.5 and 1.5 x min ventilation (VE) (C0.5 and C1.5, respectively) and a Jackson-Rees system at FGF of 1.5 and 3.0 x VE (JR1.5 and JR3.0, respectively) were used in each patient in a random order. Tidal volume (VT), mean inspiratory flow (VT divided by the duration of inspiration TI, VT/TI), and the initial fast slopes of the airway occlusion pressure phase (delta P degrees/delta t FAST) were significantly lower (P less than 0.05) with the Jackson-Rees than with the circle system, indicating greater impedence to spontaneous breathing with the Jackson-Rees system. The Jackson-Rees system also required a greater peak transpulmonary pressure (PtpMAXe) than did the circle system to achieve the same peak expiratory flows (VMAXe, P less than 0.05), again suggesting an increased resistance with the Jackson-Rees system. These results are most likely explained by the difference in elastic loads (two to three times more with the Jackson-Rees systems) between the two systems. The pediatric circle system appears to be a reliable alternative to the Jackson-Rees system.
Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota.
J P
JP
Conterato
S G
SG
Lindahl
D M
DM
Meyer
J A
JA
Bires
D000764:Anesthesia, Closed-Circuit / Q000295:instrumentation*; D000769:Anesthesia, Inhalation / Q000295:instrumentation*; D002675:Child, Preschool; D004842:Epispadias / Q000601:surgery; D005069:Evaluation Studies as Topic; D005402:Fistula / Q000601:surgery; D006221:Halothane; D006439:Hemodynamics; D006801:Humans; D007021:Hypospadias / Q000601:surgery; D007223:Infant; D011897:Random Allocation; D012119:Respiration; D014522:Urethral Diseases / Q000601:surgery
D006221:Halothane