The effects of lactated Ringer’s solution (LRS) or LRS and 6% hetastarch on the colloid osmotic pressure, total protein and osmolality in healthy horses under general anesthesia

Abstract

Objective To investigate changes in colloid osmotic pressure (COP), total protein (TP) and osmolality (OSM) during anesthesia in horses given intravenous lactated Ringer’s solution (LRS) or LRS and hetastarch (HES). Study design Prospective, clinical trial. Animals Fourteen horses presented for surgery. Mean age 8.3 ± 1.9 years; mean weight 452 ± 25 kg. Methods Horses were premedicated with xylazine intravenously (IV); anesthesia was induced with ketamine and diazepam IV, and maintained with sevoflurane. Butorphanol was administered IV with pre-medications or immediately after induction. Xylazine was administered IV for recovery if necessary. LRS was administered IV to all horses with a target rate of 5–10 mL kg−1 hour−1. Half of the horses also received 6% HES, 2.5 mL kg−1 over 1 hour in addition to LRS. Horses that received LRS only were considered the LRS group. Horses that received both LRS and HES were considered the LRS/HES group. Blood was drawn pre- and post-anesthesia, immediately following induction, and every 30 minutes throughout anesthesia. COP, TP and OSM were measured. Results COP and TP significantly decreased at similar rates for both treatment groups from pre-anesthetic values. Pre-anesthetic COP was significantly greater in the LRS group when compared to the LRS/HES group pre-, post- and throughout anesthesia. In the LRS group post-anesthetic OSM was significantly different than the pre-anesthesia value and that for the LRS/HES group. Conclusions and clinical relevance Administration of IV HES (2.5 mL kg−1, over 1 hour) in combination with LRS does not attenuate the decrease in COP typically seen during anesthesia with crystalloid administration alone. Based on these results, administration of HES at this rate and total volume would not be expected to prevent fluid shifts into the interstitium through its effects on COP.

Hydroxyethyl starches in equine medicine

“…This was not studied or demonstrated with other HES solutions or in critically ill horses. The failure to demonstrate an increase in plasma COP in 1 report using 2.5 mL/kg hetastarch 6% in anesthetized horses may be due to the low administered dose and/or the decrease in plasma COP that occurs with anesthesia itself …”

“…In healthy horses, hetastarch had a longer‐lived effect than tetrastarch, and a longer effect of hetastarch was noted in colitis horses compared to postoperative small intestinal and large intestinal ileus cases . Healthy anesthetized horses do not show greater hemodilution at the low dose of 2.5 mL/kg hetastarch when compared with crystalloids, though superiority is seen at dosages of 6 mL/kg pentastarch . In healthy conscious horses receiving 10 mL/kg of different HES types (6% HES 600/0.75, 6% HES 130/0.4, 10% HES 200/0.5), hemodilution was superior to crystalloids.…”

“…HES administration provides hemodilution based on reduced packed cell volume or total plasma protein and albumin concentrations . The intensity and duration of hemodilution are dose–dependent in healthy anesthetized and not anesthetized horses .…”

Comparison of the effect of two Ringer-Lactate-Solutions on electrolyte-, lactate- and acid-base-status in horses during balanced long-term-anaesthesia with Isoflurane and Medetomidine

“…Die Infusionsraten der Kristalloid-und Kolloidlösungen waren für beide Gruppen identisch (M30 -M120: RLF und RLB 10 ml/kg/h, M120 -M360 : RLF 13,82 ± 3,35 ml/kg/h, RLB 10,33 ± 0,46 ml/kg/h, HAES-RLF 1,07 ± 0,12 ml/kg/h, HAES-RLB 1,12 ± 0,27 ml/kg/h). Die Elektrolyt-, Laktat-sowie Säure-Base- Bei gesunden anästhesierten Pferden mit alleiniger Verabreichung von 10 ml/kg/h RL konnten keine signifikanten Naund Cl-Veränderungen über eine 150-Minuten-Allgemeinanästhesie festgestellt werden (Boscan et al 2007), ebenso nicht, wenn 5 -10 ml/kg/h RL für 150 Minuten mit 2,5 ml/kg/h 6 % HAES für 60 Minuten kombiniert wurden (Wendt-Hornickle et al 2011). Bei Distanzpferden konnte nach 20 L einer intravenös verabreichten ausgewogenen kristalloiden Flüssigkeit mit Acetat als Buffer eine Erhöhung des Na um 0,68 % und des Cl um 2,94 % beobachtet werden (Fielding et al 2012).…”

Comparison of the pharmacokinetics of two formulations of hydroxyethyl starch in healthy horses

“…Reported adverse effects of HES solutions include allergic reactions, renal injury, coagulopathy, and tissue accumulation (Jungheinrich, 2007;Hartog et al, 2011). The effects of HES solutions on hemodynamics and COP have been studied in healthy horses (Jones et al, 1997;Schusser et al, 2007;Wendt-Hornickle et al, 2011;Ohta et al, 2013;Epstein et al, 2014;Viljoen et al, 2014) and horses with naturally occurring or experimental disease (Jones et al, 2001;Hallowell & Corley, 2006;Pantaleon et al, 2006;Schusser et al, 2007;Bellezzo et al, 2014). Additionally, in vitro (Blong et al, 2013) and in vivo (Jones et al, 1997;Schusser et al, 2007;Epstein et al, 2014;Viljoen et al, 2014) studies have been performed to evaluate effects of HES solutions on coagulation in horses.…”