Effects of dexmedetomidine on pulse pressure variation changes induced by hemorrhage followed by volume replacement in isoflurane‐anesthetized dogs

Abstract

During ISO anesthesia, PPV increases in individuals prone to developing hypotension from hypovolemia. Because DEX prevents the increase in PPV associated with hypovolemia, PPV should not be used to guide VR in dogs that have been given DEX.

Evaluation of pulse pressure variation and pleth variability index to predict fluid responsiveness in mechanically ventilated isoflurane‐anesthetized dogs

“…Second, fluid administration during anesthesia is often considered in the situation of hypotension where acepromazine could be involved. Third, other premedications such as dexmedetomidine have been shown to alter PPV independent of volume status . Thus, although avoiding premedication may reduce potential confounding factors, it makes extrapolation to the clinical situation more difficult.…”

“…Both PPV and PVI are derived from respiratory changes in arterial blood pressure waveform and the plethysmography waveform of a noninvasive pulse oximeter caused by positive pressure ventilation (Figure ). In mechanically ventilated anesthetized dogs, PPV and PVI increased consistently with decreased blood volume and decreased with volume expansion . In hypovolemic or hemorrhagic patients, the intrathoracic veins are compressed by the raised intrathoracic pressure, causing large oscillations in SV and arterial pressure, thus increase in PPV and PVI.…”

“…Pulse pressure variation (PPV) and pleth variability index (PVI) are dynamic parameters that are measurable in veterinary practice . Both PPV and PVI are derived from respiratory changes in arterial blood pressure waveform and the plethysmography waveform of a noninvasive pulse oximeter caused by positive pressure ventilation (Figure ).…”

Melatonin pretreatment improves gastric mucosal blood flow and maintains intestinal barrier function during hemorrhagic shock in dogs

“…A wide range of MAP values in anesthetized dogs can be found in the literature depending on dog breed, weight, and type of anesthesia. One study in dogs reported MAP values under baseline around 80 mm Hg, while another study in dogs (11‐45 kg) reported a MAP from 50 to 90 mm Hg . The most fitting study using dogs (mean weight 30 kg) studied the effect of different concentrations of sevoflurane on mean aortic pressure.…”

Effects of 6% tetrastarch or lactated Ringer's solution on blood coagulation in hemorrhaged dogs

“…Based on a pilot study, the hemorrhage model targeting a decrease in hematocrit to 33% would allow removal of approximately 30% of blood volume (24 mL/kg, considering the blood volume as 80 mL/kg). In a previous study of dogs anesthetized using a fixed end‐tidal isoflurane concentration (1.3 times the minimum alveolar concentration), removal of 30% of blood volume resulted in hypotension (MAP < 60 mm Hg) in half of the studied population (4/8 dogs) . Because of concerns with renal injury in animals that would receive a fluid that might predispose to renal damage (TS), the end‐tidal isoflurane concentration was adjusted to provide immobility and to maintain MAP within ranges that usually are considered acceptable during anesthesia (MAP between 60 and 70 mm Hg) …”