title: Effects of fluid load on cardiovascular function during stepwise lung recruitment manoeuvre in healthy dogs.
abstract: The aim of this study was to evaluate the effects of a stepwise lung recruitment manoeuvre (RM) on cardiac output (CO) in mechanically ventilated dogs, with or without a previous fluid load. Eight healthy adult Beagle dogs were enrolled in a prospective crossover study. Following sedation with dexmedetomidine and methadone, anaesthesia was induced with propofol and maintained with isoflurane. CO (thermodilution method) and direct arterial blood pressure were monitored. The dogs were mechanically ventilated in a volume-controlled mode (tidal volume, VT = 10 mL/kg; positive end-expiratory pressure [PEEP] = 0 cm H2O) until normocapnia was achieved (end tidal CO2 35-45 mmHg). The RM was then performed in a pressure-controlled mode, with progressive increases of the PEEP and end-inspiratory pressure of 5 cm H2O, until 15 cm H2O and 30 cm H2O were reached, respectively. After the RM, the ventilatory mode was returned to volume-control, and the PEEP was sequentially decreased to 10, 5 and 0 cm H2O. Baseline ventilation was maintained for 30 min. Next, 10 mL/kg of lactated Ringer's solution was administered within 10 min, prior to a second RM. The CO was determined before each RM (baseline) and at each pressure step. A repeated measures ANOVA test was used to compare data. Compared to baseline, CO decreased during the RM in both groups. However, there was a significantly higher CO during the second RM at the highest pressure step (P<0.05) and during all decreasing pressure steps (P<0.05). In conclusion, a previous crystalloid fluid load could reduce the impact of a RM on CO in healthy dogs.
authors.affiliation: Department of Animal Medicine and Surgery, Veterinary Faculty, Complutense University of Madrid, Avda. Puerta de Hierro s/n, Madrid 28040, Spain. Electronic address: scanfran@vet.ucm.es.
authors.forename: S
authors.initials: S
authors.lastname: Canfrán
authors.forename: I A
authors.initials: IA
authors.lastname: Gómez de Segura
authors.forename: R
authors.initials: R
authors.lastname: Cediel
authors.forename: J
authors.initials: J
authors.lastname: García-Fernández
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary; D000818:Animals; D001794:Blood Pressure; D002302:Cardiac Output; D004285:Dogs / Q000502:physiology*; D008168:Lung / Q000502:physiology*; D008176:Lung Volume Measurements / Q000379:methods / Q000662:veterinary*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012121:Respiration, Artificial / Q000662:veterinary; D015656:Respiratory Mechanics / Q000502:physiology; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D012965:Sodium Chloride
keywords: Canine anaesthesia; Cardiac output; Lung recruitment; Mechanical ventilation