Continuous non-invasive arterial pressure measurement: evaluation of CNAP device during vascular surgery.

OBJECTIVE: Standard non-invasive blood pressure (BP) monitoring is an intermittent, discontinuous procedure. Beat-to-beat BP monitoring requires invasive measurement via an arterial catheter and may be associated with serious complications. The Infinity CNAP SmartPod (Dräger Medical AG & Co. KG, Lübeck, Germany) has recently been proposed for non-invasive continuous beat-to-beat BP measurements. The present study was designed to compare BP obtained with the CNAP and with an invasive method in the operating room. STUDY DESIGN: Prospective study. PATIENTS AND METHODS: Twenty-five patients undergoing major vascular surgery were included. Systolic, mean and diastolic BP were monitored invasively (SAP, MAP and DAP respectively) and not invasively using the CNAP (CNAP-S, CNAP-M and CNAP-D respectively). Measurements were performed intraoperatively every minute during 1 hour. RESULTS: One thousand and five hundred pairs of simultaneous CNAP and invasive BP measurements were obtained and 148 were eliminated. The range of BP measurements was 63-205 mmHg for SAP and 57-187 mmHg for CNAP-S, 38-143 mmHg for MAP and 43-142 mmHg for CNAP-M, 29-126 mmHg for DAP and 33-121 mmHg for CNAP-D. Bias and 95% limit of agreement between CNAP and invasive BP measurements were respectively 7.2 and -17.7 to 32.2 mmHg for SAP, -1.8 and -22.0 to 18.3 mmHg for MAP, and -7.5 and -27.3 to 12.4 mmHg for DAP. The percentage of CNAP measurements with a bias <10% with the arterial line was 69%, 86% and 91% for systolic, diastolic and mean pressures, respectively. CONCLUSION: Despite low accuracy for SAP and DAP measurements, CNAP system seems more accurate for MAP measurement in patients undergoing vascular surgery.

[Iatrogenic gas embolism after the use of hydrogen peroxide]. / Embolie gazeuse iatrogène après utilisation de peroxyde d'hydrogène.

We report a case of severe oxygen embolism after wound irrigation under pressure with hydrogen peroxide into a closed or partially closed cavity. The accident was observed during a surgical dressing of a large pelvis gangrene area, after a 250 ml injection of hydrogen peroxide. Suddenly occurred a decrease in PETCO(2) and SpO(2), and then heart arrhythmia. Symptomatic treatment initiated immediately restored SpO(2) and heart rhythm within a few minutes and the patient was then treated with hyperbaric oxygen therapy. The patient recovered without cardiac or neurologic sequelae. The release of gaseous oxygen under the effect of tissue catalase and the vascular diffusion of this oxygen bubbles can explain such complication. Injection of large volume of hydrogen peroxide into a closed or partially closed cavity and/or under pressure injection must be prohibited.