Comparison of Respiratory Variations of the Pulse Oximetry Plethysmographic Raw Signal and Pulse Pressure During Abdominal Surgery (PLETHYSMO)

Comparison of Respiratory Variations of the Pulse Oximetry Plethysmographic Raw Signal and Pulse Pressure During Abdominal Surgery (PLETHYSMO)

The waveform plethysmographic signal can be used to establish an index for predicting fluid responsiveness (∆POP: respiratory variation of the plethysmographic waveform of pulse oximetry). This index was validated in some studies and because of its non-invasiveness it seems very interesting in anesthesia.

However, in a previous study the investigators evaluated the correlation between the results provided by this index (∆POP) and those of the reference index (∆PP: pulse pressure variation), and the obtained results were significantly lower than what had been previously described. In this study, the index was calculated from a recording of a filtered signal. This unavoidable application of a filter on anesthesia monitors could contribute to the discrepancy between the ∆POP and the ∆PP.

The realization of a new study, comparing ∆PP and ∆POP obtained from an unfiltered plethysmographic signal, should answer the ∆POP ability to be used in place of ∆PP.

Inclusion Criteria:

• Hospital patient in general surgery and digestive department
• Adult
• Digestive sus mesocolic surgery with direct abdominal approach justifying a semi-invasive hemodynamic monitoring by arterial catheterization (liver, pancreatic, gastric and duodenal surgery)
• Surgical approach by laparotomy
• Patient under general anesthesia with mechanical ventilation
• Agreeing to participate in the study after receiving information note

Exclusion Criteria:

• Known left systolic ventricular and/or diastolic failure
• Arrhythmias
• Surgery performed with thoracic approach
• Surgery by laparoscopy
• Emergency surgery
• Hypersensitivity or allergic to any of the product used for usual anesthesia, hypersensitivity to soya or egg lecithin
• Personal or familial history of malignant hyperthermia
• Severe kidney impairment (creatinin clearance <30ml/min)
• Patients who participated in the previous month to another study protocol
• Pregnant women or nursing
• Under-age