Objective—To determine whether increasing the viscosity of a standard hemoglobin-based oxygen-carrying solution (HBOC) would offset its associated vasoconstrictive effects and result in improved microvascular perfusion in healthy splenectomized dogs with experimentally induced hemorrhagic shock.
Animals—12 male American Foxhounds.
Procedures—Each dog underwent anesthesia and splenectomy. Shock was induced by controlled hemorrhage until a mean arterial blood pressure of 40 mm Hg was achieved and maintained for 60 minutes. Dogs were then randomly assigned to receive either a standard or hyperviscous HBOC (6 dogs/group). Sidestream dark-field microscopy was used to assess the effects of shock and HBOC administration on the microcirculation of the buccal mucosa and the jejunal serosa. Video recordings of the microcirculation were collected before shock was induced (baseline) and at intervals up to 180 minutes following HBOC administration. Vascular analysis software was used to compute microcirculatory variables.
Results—Compared with baseline findings, hemorrhagic shock resulted in decreases in all microvascular variables in the buccal mucosa and the jejunal serosa. At all time points following HBOC administration, microvascular variables were similar to initial values and no significant differences between treatment groups were detected. At all time points following HBOC administration, blood and plasma viscosities in dogs treated with the hyperviscous solution were significantly higher than values in dogs receiving the standard solution.
Conclusions and Clinical Relevance—In splenectomized dogs with experimentally induced hemorrhagic shock, administration of a hyperviscous HBOC did not significantly affect microvascular variables, compared with effects of a standard HBOC. Microcirculatory flow returned to baseline values in both treatment groups, suggesting that marked HBOC-associated vasoconstriction did not occur.
Objective—To assess the agreement between cardiac output (CO) measured by use of arterial pressure waveform analysis (PulseCO) and lithium dilution (LiDCO) in conscious dogs with systemic inflammatory response syndrome (SIRS).
Animals—14 dogs with naturally occurring SIRS.
Procedures—Pulse power analysis was performed on critically ill patients with a PulseCO monitor. All measurements were obtained with an indwelling arterial line and in accordance with the manufacturer's instructions. Intermittent measurements of CO were obtained with the LiDCO method to validate the PulseCO measurements at initial calibration (baseline; time 0) and at 4, 8, 16, and 24 hours. The 2 methods for measuring CO were compared by use of Bland-Altman analysis. An error rate for the limits of agreement between the 2 methods of < 30% was defined as being acceptable.
Results—Bland-Altman analysis did not indicate good agreement between measurements obtained by use of the PulseCO and LiDCO methods, despite no significant change in cardiac index (CI) over time as measured with the LiDCO method. The percentage error for the overall difference in CI values between the PulseCO and LiDCO measurements was 122%, which indicated that the PulseCO method was not an acceptable means of CO measurement when compared with the LiDCO method for this patient population.
Conclusions and Clinical Relevance—Agreement between the PulseCO and LiDCO methods for measurement of CO was not acceptable at 4- and 8-hour intervals after calibration in conscious dogs with naturally occurring SIRS.