Measurement of maximal inspiratory pressure in ventilated children

Abstract

Maximal inspiratory pressure (PIMAX), the maximum negative pressure generated during temporary occlusion of the airway, is commonly used to measure inspiratory muscle strength in mechanically ventilated infants and children. There are, however, no guidelines as to how the PIMAX measurement should be made. We compared the maximum inspiratory pressure generated during airway occlusion (PIMAX OCC ) to that when a unidirectional valve (PIMAX UNI ), which allowed expiration, but not inspiration was used.Twenty two mechanically ventilated children (mean (SD) age 4.8 (4.5) years) were studied. Three sets of end expiratory occlusions were performed for each method in random order. The expired volume during PIMAX UNI was assessed and related to the functional residual capacity (FRC) measured using a helium dilution technique.The mean (SD) PIMAX UNI (45.5 (15.2) cmH 2 O) was significantly greater than mean (SD) PIMAX OCC (30.9 (9.0) cmH 2 O) (p<0.0001). The mean (SD) expired volume during PIMAX UNI , was 98 ml (62.3), a mean reduction in FRC of 33.1% (SD 13.9). There were no significant differences between techniques in the baseline respiratory drive, the number of efforts required and the time to reach PIMAX. Regardless of technique, PIMAX was reached in 10 inspiratory efforts or 15sec of airway occlusion.A unidirectional valve allowing expiration, but not inspiration yields greater PIMAX values in children. Occlusions should be maintained for 12 seconds or eight breaths (99% CI of mean).

Neonatal and Adult ICU Ventilators to Provide Ventilation in Neonates, Infants, and Children: A Bench Model Study

“…The 18,19 and can, under some circumstances such as during sleep or with small infants, be very low, [20][21][22] we chose to simulate this as well. Neonatal options of the Fabian and Evita XL NeoFlow ventilators were tested with R100C2, and R50C5; pediatric options of the same ventilators were tested with R50C5 and R30C10.…”

Parasternal intercostal electromyography: a novel tool to assess respiratory load in children

“…In our study, the difficulties associated with acquiring reliable maximal EMGpara signals were highlighted by the finding that such measures could only be obtained in 56 of the 92 healthy subjects, and in none of the preschool children with wheeze. Similarly, achieving reliable maximal inspiratory efforts is difficult in intubated, sedated pediatric patients, and can only be obtained by using maintained endotracheal tube (ETT) occlusion (15). ETT occlusion may not, however, represent a suitable method for obtaining maximal EMGpara as inhibition of parasternal intercostal muscle activity during static (isovolume) inspiratory maneuvers has been demonstrated (16).…”

Inspiratory muscle conditioning exercise and diaphragm gene therapy in Pompe disease: Clinical evidence of respiratory plasticity

“…We used the one-way inspiratory occlusion method validated in pediatric ICU patients. (Harikumar et al, 2008) To summarize, the tracheostomy cuff was inflated for invasively ventilated subjects prior to the test. Then, subjects were removed briefly from the ventilator, and a pressure manometer and one-way valve were attached directly to the tracheostomy tube.…”