Small-volume 7.5% NaCI adenosine lidocaine, and Mg2+ has multiple benefits during hypotensive and blood resuscitation in the pig following severe blood loss: rat to pig translation

Objectives: Currently, there is no effective small-volume fluid for traumatic hemorrhagic shock. Our objective was to translate small-volume 7.5% NaCl adenosine, lidocaine, and Mg^2+ hypotensive fluid resuscitation from the rat to the pig. Design: Pigs (35–40 kg) were anesthetized and bled to mean arterial pressure of 35–40 mm Hg for 90 minutes, followed by 60 minutes of hypotensive resuscitation and infusion of shed blood. Data were collected continuously. Setting: University hospital laboratory. Subjects: Female farm-bred pigs. Interventions: Pigs were randomly assigned to a single IV bolus of 4 mL/kg 7.5% NaCl + adenosine, lidocaine and Mg^2+ (n = 8) or 4 mL/kg 7.5% NaCl (n = 8) at hypotensive resuscitation and 0.9% NaCl ± adenosine and lidocaine at infusion of shed blood. Measurements and Main Results: At 60 minutes of hypotensive resuscitation, treatment with 7.5% NaCl + adenosine, lidocaine, and Mg^2+ generated significantly higher mean arterial pressure (48 mm Hg [95% CI, 44–52] vs 33 mm Hg [95% CI, 30–36], p < 0.0001), cardiac index (76 mL/min/kg [95% CI, 63–91] vs 47 mL/min/kg [95% CI, 39–57], p = 0.002), and oxygen delivery (7.6 mL O2/min/kg [95% CI, 6.4–9.0] vs 5.2 mL O2/min/kg [95% CI, 4.4–6.2], p = 0.003) when compared with controls. Pigs that received adenosine, lidocaine, and Mg^2+/adenosine and lidocaine also had significantly lower blood lactate (7.1 mM [95% CI, 5.7–8.9] vs 11.3 mM [95% CI, 9.0–14.1], p = 0.004), core body temperature (39.3°C [95% CI, 39.0–39.5] vs 39.7°C [95% CI, 39.4–39.9]), and higher base excess (–5.9 mEq/L [95% CI, –8.0 to –3.8] vs –11.2 mEq/L [95% CI, –13.4 to –9.1]). One control died from cardiovascular collapse. Higher cardiac index in the adenosine, lidocaine, and Mg^2+/adenosine and lidocaine group was due to a two-fold increase in stroke volume. Left ventricular systolic ejection times were significantly higher and inversely related to heart rate in the adenosine, lidocaine, and Mg^2+/adenosine and lidocaine group. Thirty minutes after blood return, whole-body oxygen consumption decreased in pigs that received adenosine, lidocaine, and Mg2+/adenosine and lidocaine (5.7 mL O2/min/kg [95% CI, 4.7–6.8] to 4.9 mL O2/min/kg [95% CI, 4.2–5.8]), whereas it increased in controls (4.2 mL O2/min/kg [95% CI, 3.5–5.0] to 5.8 mL O2/min/kg [95% CI, 4.9–5.8], p = 0.02). After 180 minutes, pigs in the adenosine, lidocaine, and Mg^2+/adenosine and lidocaine group had three-fold higher urinary output (2.1 mL//kg/hr [95% CI, 1.2–3.8] vs 0.7 mL//kg/hr [95% CI, 0.4–1.2], p = 0.001) and lower plasma creatinine levels. Conclusion: Small-volume resuscitation with 7.5% NaCl + adenosine, lidocaine, and Mg^2+/adenosine and lidocaine provided superior cardiovascular, acid-base, metabolic, and renal recoveries following severe hemorrhagic shock in the pig compared with 7.5% NaCl alone