Optimal crystalloid volume ratio for blood replacement for maintaining hemodynamic stability and lung function: An experimental randomized controlled study

Gergely H. Fodor, Walid Habre, Adam L. Balogh, Roberta Südy, Barna Babik, Ferenc Peták

Research output: Contribution to journalArticle


Background: Crystalloids are first line in fluid resuscitation therapy, however there is a lack of evidence-based recommendations on the volume to be administered. Therefore, we aimed at comparing the systemic hemodynamic and respiratory effects of volume replacement therapy with a 1:1 ratio to the historical 1:3 ratio. Methods: Anesthetized, ventilated rats randomly included in 3 groups: blood withdrawal and replacement with crystalloid in 1:1 ratio (Group 1, n = 11), traditional 1:3 ratio (Group 3, n = 12) and a control group with no interventions (Group C, n = 9). Arterial blood of 5% of the total blood volume was withdrawn 7 times, and replaced stepwise with different volume rations of Ringer's acetate, according to group assignments. Airway resistance (Raw), respiratory tissue damping (G) and tissue elastance (H), mean arterial pressure (MAP) and heart rate (HR) were assessed following each step of fluid replacement with a crystalloid (CR1-CR6). Lung edema index was measured from histological samples. Results: Raw decreased in Groups 1 and 3 following CR3 (p < 0.02) without differences between the groups. H elevated in all groups (p < 0.02), with significantly higher changes in Group 3 compared to Groups C and 1 (both p = 0.03). No differences in MAP or HR were present between Groups 1 and 3. Lung edema was noted in Group 3 (p < 0.05). Conclusions: Fluid resuscitation therapy by administering a 1:1 blood replacement ratio revealed adequate compensation capacity and physiological homeostasis similar with no lung stiffening and pulmonary edema. Therefore, considering this ratio promotes the restrictive fluid administration in the presence of continuous and occult bleeding.

Original languageEnglish
Article number21
JournalBMC anesthesiology
Issue number1
Publication statusPublished - Feb 13 2019



  • Fluid replacement
  • Fluid resuscitation
  • Lung function
  • Pulmonary edema
  • Respiratory mechanics

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

Cite this