The pericardium acts as a restricting factor on the release of ANF (1-98) and ANF (99-126) after volume loading in pigs

Gunanti Soeyono DV, Bardosono S, Jusman S, Siagian M, Lubis M. Resuscitation of hemorrhagic shock using normal saline does not damage the glycocalyx in the immediate resuscitation phase

OBJECTIVES:

The objectives were to study the effect of aggressive resuscitation using normal saline on hemodynamics, serum atrial natriuretic peptide (ANP), syndecan-1 (marker of endothelial glycocalyx shedding), and extravascular lung water index (ELWI) following hemorrhagic shock.

METHODS:

Eleven male piglets (Sus scrofa) underwent blood drawing to create 20% drop in mean arterial pressure (MAP). Two-phase resuscitation was performed: Phase 1 using normal saline of an equal volume of blood drawn to create shock and Phase 2 using 40 ml/kg BW of normal saline to simulate hypervolemia and hemodilution. Heart rate, MAP, cardiac index (CI), systemic vascular resistance index, oxygen delivery (DO₂), global end-diastolic volume index, ELWI, hemoglobin (Hb), lactate, ANP, and syndecan-1 at each phase and up to 60 min following Phase 2 resuscitation were recorded.

RESULTS:

Phase 2 resuscitation significantly decreased Hb concentration (P = 0.006), however, DO₂ was maintained (P = 1.000). CI increased from shock to Phase 1 (P = 0.029) and further increase in Phase 2 resuscitation (P = 0.001). Overall, there was a transient increase of ANP following Phase 1 resuscitation, from 85.20 ± 40.86 ng/L at baseline to 106.42 ± 33.71 ng/L (P = 0.260). Serum syndecan-1 and ELWI change at all phases were not significant.

CONCLUSIONS:

We demonstrate compensatory protective mechanism despite overzealous fluid resuscitation. Compensatory increased CI despite decreased Hb maintained DO₂. In the absence of inflammation, serum ANP did not increase significantly, no glycocalyx shedding occurred, subsequently no change in ELWI. We show that factors other than volume overload are more dominant in causing glycocalyx shedding.

Neurohormonal responses during positive pressure mechanical ventilation

Positive pressure mechanical ventilation is used daily in critical care units to support ventilation and improve oxygenation in critically ill patients. One adverse response to positive pressure mechanical ventilation is a reduction in urinary output and sodium and water retention. This consequence is attributed to complex neurohormonal responses intended to maintain hemodynamic homeostasis. This article reviews the physiologic nature of these responses and research findings related to these responses and provides clinicians with information about the importance of these responses, particularly in patients with underlying cardiac dysfunction.