Study objective: Patients submitted to major vascular surgery often match Metabolic Syndrome's (MetS) risk factors and consequently they are affected by high postoperative risk of cardio circulatory, respiratory and renal dysfunctions, which can worsen the outcome. Hemodynamic variations occurring during aortic surgery may expose patients at risk for cardiac complications, particularly myocardial ischemia. Positive end-expiratory pressure applied to mechanical ventilation only during clamping phase may protect heart against stress due to augmented blood return when aorta is clamped and may reduce the sudden lowering of blood pressure if it is discontinued when circulation is restored. Further it may reduce postoperative complications rate. Design: Randomized controlled trial Setting: Vascular surgery operative room. Patients: 124 patients (ASA 2-4) were divided into two groups: ZEEP (zero end-expiratory pressure, control group) and PEEP (positive end-expiratory pressure, treated group). They underwent vascular surgery operation for elective abdominal aortic reparation. Interventions: When aorta was clamped, we applied PEEP 10 cm H2O to mechanical ventilation. When surgeon removed the clamp, we discontinued PEEP. Measurements: Blood pressure, Heart rate, Blood-gas analysis, Fluid balance, Cardiac output, Stroke volume variation, Brain Natruretic Peptide, Serum Creatinine and Troponine I,outcome (length-of-stay, complications rate). Main results: After unclamping, blood pressure of ZEEP-group fell more than in PEEP-group (SAP -21.4 ± 22.8% vs -5.5 ± 21.5%, p=0.000; MAP -18.6 ± 23.6% vs -5.8 ± 23.5%, p=0.003). In treated group, a significant lower number of patients with MetS risk factors experienced postoperative complications than in control group (p=0.005). Conclusions: Application of PEEP when abdominal aorta is clamped and its discontinuation just when circulation is restored may guarantee a better hemodynamic setting and a safer postoperative outcome.
- Aortic surgery
- Metabolic syndrome
- Positive end-expiratory pressure
ASJC Scopus subject areas
- Anesthesiology and Pain Medicine