Page 74 - Physiological based CPAP for preterm infants at birth Tessa Martherus

Chapter 3
Other outcome measures
Outputs from the pressure transducer (attached to the oesophageal tube), oximeter, and temperature probe were digitized and recorded by Labchart. Breathing rates were derived from the intrathoracic oesophageal pressure measurements and calculated as (60 s/interval duration in seconds) × number of breaths. All outcomes were assessed while the kittens were on CPAP and were spontaneously breathing on CPAP, prior to the start of IPPV. Other outcome measures include periods of IPPV. If a pneumothorax was clearly visible during imaging (Figure 2a), this resulted in the immediate cessation of the experiment for that kitten. CPAP belly (defined as air within the stomach that changed the shape of the abdomen, Figure 2b, c) and bulging of the non-dependent (in the figure, upper) lung between the ribs at end-expiration (categorized as non/minor/significant, Figure 2d-f) and were visually assessed by TM, SH, and AtP after the experiment.
Figure 2. Phase contrast X-ray imaging. Phase contrast X-ray images showing a) a pneumothorax, b) CPAP belly that was assessed as insignificant when the stomach contained air, but did not change the shape of the abdomen, and c) CPAP belly that was assessed as significant when the amount of air within the stomach affected the shape of the abdomen. Bulging of the non-dependent lung between the ribs was assessed at end-expiration as either d) absent, e) minor, or f) significant.
70