This study was conducted to find out whether it is possible to adjust the driving pressure (DP) of the jet ventilator (JV) during HFJV in rigid bronchoscopy (RB) by measuring tcPCO2.PATIENTS AND METHOD: After approval of the Ethics Committee and informed consent, 70 patients (42 m, 28 f), ASA I-III, mean age: 57.6 y, mean weight 76.6 kg were scheduled for the study.STUDY PROTOCOL: During RB in TIVA (propofole, remifentanyl, succinylcholine) carbon dioxide was monitored transcutaneously (TOSCA; Linde Medical Sensors; Switzerland). The initial DP (20 mbar/kg BW), was changed in 20% steps aiming at a tcPCO2 of 40–50 torr. After the end of bronchoscopy the pat. was ventilated for another 10 min using the last setting applied. An arterial blood gas analysis was taken to compare with the simultaneous tcPCO2.
Mean duration of HFJV was 17.21 min (10–40) with DP 1.1–4,0 bar. The correlation between tcPCO2 und PaCO2 was 0.91, S.E.E: 3.48 torr. The bias was 3.72 torr, the SD 3.46 torr (Bland and Altman). In 62 patients the adjustment of the DP was correct, i.e. 35 pat. were normoventilated, in 13 pat. hypocapnia induced a reduction, in 14 pat. hypercapnia an increase of DP.
HFJV could be controlled correctly by measurement of the ptCO2 in 88% of our pat. This reflects the good correlation between PaCO2 and tcCO2 using the TOSCA-monitor. The difference between 62 pat. with correct adjustment of the DP and the normoventilated pat. (n=35) is explained by the mean duration of HFJV being too short for repeated DP adjustments.
Especially with weighty pat., pat. with pulmonary diseases, during long lasting procedures with endobronchial interventions, measurement of ptCO2 is helpful to adjust the DP of the JV aiming at normocarbia.
C. Männle, None.