Yannik Kalbas (Zurich / CH), Yohei Kumabe (Zurich / CH), Sascha Halvachizadeh (Zurich / CH), Felix Karl Ludwig Klingebiel (Zurich / CH), Michel Paul Johan Teuben (Zurich / CH), Hans-Christoph Pape (Zurich / CH), Roman Pfeifer (Zurich / CH)
Abstract text (incl. references and figure legends)
Purpose: Occult hypoperfusion(OH) describes the absence of sufficient microcirculation despite normal vital signs. It can be quantified via persistent lactatemia and is associated with complications and a reduced outcome. Our study aims to identify potential causes for occult hypoperfusion after hemorrhagic shock (HS) in a porcine polytrauma model.
Methods: 25 male Pigs (50 ± 5kg) underwent general anesthesia for 6 hours. They received a combined injury of blunt chest trauma with a lung contusion, a grade II (AAST) liver laceration, controlled HS (mean arterial pressure 30 ± 5 mm Hg for 60 minutes), and femoral shaft fracture. After 60 minutes, animals were resuscitated. Microcirculation was evaluated using near-infrared spectroscopy on the M. vastus lateralis of the fractured and uninjured site as well as on liver, stomach and colon. Lactate was measured via blood gas analysis. All measurements were taken at baseline, during HS at 15/30/45/60 min, and after resuscitation at 2h,4h and 6h. OH was defined as persistent lactatemia (>2mmol/l) at 6h.
Results: Lactate normalized in 18 animals (72%) after resuscitation (control). Four animals (16%) were diagnosed with OH. Three animals (12%) died during the observation period. Vital parameters (RR, SaO2, and Schock Index) didn"t differ between groups. Lactate was significantly higher in OH at 2h and 6h (p = 0.039 and p = 0.001). Significantly higher local bloodflow was noted during HS on the uninjured M. vastus lateralis at 30, 45, and 60 min (p = 0.012, p = 0.039 and p = 0.008) in OH compared to control. Oxygen delivery at that site was significantly higher at 45 and 60 min (p = 0.044, and p = 0.004), but lower at 4h (p = 0.039).
Conclusion: Failure to centralize during hemorrhagic shock can lead to reduced local microcirculation and persistent lactatemia after resuscitation and OH. Our results support the validity of lactate clearance as a marker of sufficient resuscitation.
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Nothing to declare