title: Hemoglobin Vesicles prolong the time to circulatory collapse in rats during apnea.
abstract: Hemoglobin vesicles (HbV) are hemoglobin-based oxygen carriers manufactured by liposome encapsulation of hemoglobin molecules. We hypothesised that the infusion of oxygenated HbV could prolong the time to circulatory collapse during apnea in rats.
  
  
  
  Twenty-four Sprague-Dawley rats were randomly divided into four groups (Air, Oxy, NS and HbV). The rats were anaesthetized with isoflurane and the trachea was intubated using 14-gauge intravenous catheters. Rats in the Air group were mechanically ventilated with 1.5% isoflurane in room air, and those in other groups received 1.5% isoflurane in 100% oxygen. Mechanical ventilation was withdrawn 1 min after the administration of rocuronium bromide to induce apnea. After 30 s, 6 mL saline and HbV boluses were infused at a rate of 0.1 mL/s in the NS and HbV groups, respectively. Circulatory collapse was defined as a pulse pressure < 20 mmHg and the time to reach this point (PP20) was compared between the groups. The results were analysed via a one-way analysis of variance and post-hoc Holm-Sidak test.
  
  
  
  PP20times were 30.4 ± 4.2 s, 67.5 ± 9.7 s, 95 ± 17.3 s and 135 ± 38.2 s for the Air (ventilated in room air with no fluid bolus), Oxy (ventilated with 100% oxygen with no fluid bolus), NS (ventilated with 100% oxygen with a normal saline bolus), and HbV (ventilated in 100% oxygen with an HbV bolus) groups, respectively, and differed significantly between the four groups (P = 0.0001). The PP20times in the HbV group were significantly greater than in the Air (P = 0.0001), Oxy (P = 0.007) and NS (P = 0.04) groups.
  
  
  
  Infusion of oxygenated HbV prolongs the time to circulatory collapse during apnea in rats.
authors.affiliation: Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan. schneider.yusuke@gmail.com.
authors.forename: Yusuke
authors.identifier: 0000-0002-1423-812X
authors.initials: Y
authors.lastname: Naito
authors.affiliation: Department of Chemistry, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sakai
authors.affiliation: Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan.
authors.forename: Satoki
authors.initials: S
authors.lastname: Inoue
authors.affiliation: Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kawaguchi
mesh_terms: D000818:Animals; D001049:Apnea / Q000150:complications*; D006454:Hemoglobins; D008081:Liposomes; D010100:Oxygen / Q000008:administration & dosage*; D017207:Rats, Sprague-Dawley; D012769:Shock / Q000209:etiology*; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D008081:Liposomes; D010100:Oxygen
keywords: Apnea; Artificial red blood cells; Hemoglobin Vesicles; Hypoxia