To determine whether pediatric anesthesiologists can reliably detect occluded tracheal tubes, 18 pediatric anesthesiologists who were blindfolded and fitted with earplugs manually ventilated the lungs of 16 neonates. Consent was obtained from the parents of the neonates. All auditory signals from the monitors were silenced. Six conditions were studied (for 3 min each) in random order: three models of Ayre's t-piece with the Jackson Rees modification and two fresh gas flows (FGF) (2 and 6 L/min). During each condition, the tracheal tube was clamped at five predetermined but randomized times. The volume/pressure relationships of the three t-piece models were determined. Tube occlusions were detected more frequently at a low FGF (82%) than at a high FGF (64%) (P < 0.001). Experienced anesthesiologists (>8 yr experience) detected occlusions (83%) more frequently than less experienced (<2 yr experience) anesthesiologists (63%) (P < 0.027). There was no interaction between FGF and experience. The type of circuit did not affect the detection rate. We conclude that during isolated hand ventilation with the t-piece, pediatric anesthesiologists can detect >80% of occluded tubes provided they use a low FGF or have >8 yr experience, but only 60% of occluded tubes at high FGF or if they have <2 yr experience.
Implications: Hand ventilation of the lungs in neonates has been used to detect changes in respiratory compliance, but laboratory models have failed to demonstrate its usefulness. We determined that pediatric anesthesiologists could detect 83% of tracheal tube occlusions in neonates if either the fresh gas flow was 2 L/minor the pediatric anesthesiologist was experienced (> 8 yr).