Dynamic parameters of fluid responsiveness in the operating room : An analysis of intraoperative ventilation...

Reliable assessment of fluid responsiveness with pulse pressure variation (PPV) depends on certain ventilation-related preconditions; however, some of these requirements are in contrast with recommendations for protective ventilation.

The aim of this study was to evaluate the applicability of PPV in patients undergoing non-cardiac surgery by retrospectively analyzing intraoperative ventilation data.

Intraoperative ventilation data from three large medical centers in Germany and Switzerland from January to December 2018 were extracted from electronic patient records and pseudonymized; 10,334 complete data sets were analyzed with respect to the ventilation parameters set as well as demographic and medical data.

In 6.3% of the 3398 included anesthesia records, patients were ventilated with mean tidal volumes (mTV) > 8 ml/kg predicted body weight (PBW). These would qualify for PPV-based hemodynamic assessment, but the majority were ventilated with lower mTVs. In patients who underwent abdominal surgery (75.5% of analyzed cases), mTVs > 8 ml/kg PBW were used in 5.5% of cases, which did not differ between laparoscopic (44.9%) and open (55.1%) approaches. Other obstacles to the use of PPV, such as elevated positive end-expiratory pressure (PEEP) or increased respiratory rate, were also identified. Of all the cases 6.0% were ventilated with a mTV of > 8 ml/kg PBW and a PEEP of 5-10 cmH₂O and 0.3% were ventilated with a mTV > 8 ml/kg PBW and a PEEP of > 10 cmH₂O.

The data suggest that only few patients meet the currently defined TV (of > 8 ml/kg PBW) for assessment of fluid responsiveness using PPV during surgery.