Excellence in Perinatal Medicine: When Skill Makes the Difference

1 DO MECHANICAL AND HUMAN FACTORS COMBINE TO OVERVENTILATE TRANSPORTED INFANTS? A. Leslie (1,2) J. Behrsin (1,2), A. Kage (1,2) Gareth Penman (2) (1) CenTre Neonatal Transport Servic; (2) University Hospitals of Leicester NHS Trust, UK Introduction A recent audit from our service demonstrated hypocarbia (pCO2<4KPa) at the end of transport in 12.5% of ventilated transports1. The Baby-pac ventilator uses analogue dials to set the ventilator parameters. We wanted to determine how accurately the Baby-pac ventilator delivered the desired ventilation settings and the accuracy of team members setting the ventilator. Methods We used a gas flow analyser (VT-plus HF) to measure the delivered PiP, PEEP, Ti and ventilator rate. Four Babypac ventilators were used in the studies. In the first study one of the authors (AL) carefully set each ventilator to deliver in turn four different typical neonatal settings. The ventilation delivered as measured by the VT-plus was noted. In the second study members of the transport team were asked to set the Baby-pac ventilator at four different settings. At each setting the VT-plus was used to measure what was delivered. Results In the first study, all the transport ventilators at all settings over-delivered PIP (median +1cm/H2O (IQR 0.71.4) and underdelivered PEEP (median -1cm/H2O (IQR 0.5-1.3). For the second study data were obtained from five transport nurses, two transport consultants, and nine middle-grade trainees. Similar trends were to study one were seen for PIP and PEEP. Only 11 of 68 ventilator rates was set completely accurately (range between 8 breaths fewer than set to 13 breaths greater). Discussion We have shown that Baby-pac ventilators consistently over-deliver on PIP settings and underdeliver on PEEP settings. Transport personnel vary in the accuracy with which the ventilator rate is set. These data suggest the move from unit ventilator to transport ventilator will result in alterations to the delivered ventilation with the potential to deliver a higher tidal volume than intended, which may have an impact on hypocarbia. This study highlights the inaccuracy of relying on the visual analogue scale to set the Baby-pac ventilator. In addition the possibility of delivering inadvertently low PEEP may have adverse consequences, such as atelectasis. Lilley’s work2 suggests that a respiratory function monitor may be effective in reducing these problems.