Continuous measurement of cerebral oxygen saturation (rSO2) for assessment of cardiovascular status during hemorrhagic shock in a swine model

Navarro, Laís Helena Camacho; Lima, Rodrigo Moreira e; Khan, Muzna; Dominguez, Wendy G.; Voigt, Richard B.; Kinsky, Michael P.; Mileski, William J.; Kramer, George C.

doi:10.1097/ta.0b013e3182606372

Cited by 10 publications

(13 citation statements)

References 29 publications

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“…This agrees with previous results in anesthetized swine that show cerebral oximetry responses matched MAP responses during hemorrhage (Navarro et al. ). Redistribution of blood flow during hemorrhage may limit oxygen delivery to peripheral regions while cerebral autoregulation maintains a sufficient supply of oxygen.…”

Section: Discussionsupporting

confidence: 93%

“…rSO 2-CERE-BRAL was relatively stable through most of the hemorrhage, but decreased toward the end of hemorrhage, and continued to decrease posthemorrhage rather than recovering with MAP. This agrees with previous results in anesthetized swine that show cerebral oximetry responses matched MAP responses during hemorrhage (Navarro et al 2012). Redistribution of blood flow during hemorrhage may limit oxygen delivery to peripheral regions while cerebral autoregulation maintains a sufficient supply of oxygen.…”

Section: Tissue Oxygenationsupporting

confidence: 93%

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Effect of hemorrhage rate on early hemodynamic responses in conscious sheep

et al. 2016

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Physiological compensatory mechanisms can mask the extent of hemorrhage in conscious mammals, which can be further complicated by individual tolerance and variations in hemorrhage onset and duration. We assessed the effect of hemorrhage rate on tolerance and early physiologic responses to hemorrhage in conscious sheep. Eight Merino ewes (37.4 ± 1.1 kg) were subjected to fast (1.25 mL/kg/min) and slow (0.25 mL/kg/min) hemorrhages separated by at least 3 days. Blood was withdrawn until a drop in mean arterial pressure (MAP) of >30 mmHg and returned at the end of the experiment. Continuous monitoring included MAP, central venous pressure, pulmonary artery pressure, pulse oximetry, and tissue oximetry. Cardiac output by thermodilution and arterial blood samples were also measured. The effects of fast versus slow hemorrhage rates were compared for total volume of blood removed and stoppage time (when MAP < 30 mmHg of baseline) and physiological responses during and after the hemorrhage. Estimated blood volume removed when MAP dropped 30 mmHg was 27.0 ± 4.2% (mean ± standard error) in the slow and 27.3 ± 3.2% in the fast hemorrhage (P = 0.47, paired t test between rates). Pressure and tissue oximetry responses were similar between hemorrhage rates. Heart rate increased at earlier levels of blood loss during the fast hemorrhage, but hemorrhage rate was not a significant factor for individual hemorrhage tolerance or hemodynamic responses. In 5/16 hemorrhages MAP stopping criteria was reached with <25% of blood volume removed. This study presents the physiological responses leading up to a significant drop in blood pressure in a large conscious animal model and how they are altered by the rate of hemorrhage.

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Section: Discussionsupporting

confidence: 93%

Section: Tissue Oxygenationsupporting

confidence: 93%

Effect of hemorrhage rate on early hemodynamic responses in conscious sheep

et al. 2016

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“…in response to anaesthetic induction) and potentially result in an over-interpretation of differing CPO responses between animals at both ends of the age span. This may explain the relatively broad range of rSO 2 values in the study by Navarro et al [ 70 ], since this study was conducted on few animals (n = 6) with body weights ranging from 21.5 to 92.8 kg and estimated ages of approximately 8–21 weeks. In parallel, the relatively wide range in MAP observed may also be a result of an uneven sensitivity to the propofol doses between animals with different age.…”

Section: Reviewmentioning

confidence: 98%

“…However, not all parameters were reported in all studies. Predefined haemodynamic baseline limits were not reported in detail in any of the studies, but Boezaart [ 68 ], Navarro et al [ 70 ], Silva et al [ 71 ] and Srinivasan et al [ 72 ], reported that haemodynamic baseline recordings had to be stable prior to intervention. MAP and the 95 % confidence interval of all studies were within the limits of cerebral autoregulation (Table 5 ).…”

Section: Reviewmentioning

confidence: 99%

Effect of propofol and remifentanil on cerebral perfusion and oxygenation in pigs: a systematic review

et al. 2015

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The objective of this review is to evaluate the existing literature with regard to the influence of propofol and remifentanil total intravenous anaesthesia (TIVA) on cerebral perfusion and oxygenation in healthy pigs. Anaesthesia has influence on cerebral haemodynamics and it is important not only in human but also in veterinary anaesthesia to preserve optimal regulation of cerebral haemodynamics. Propofol and remifentanil are widely used in neuroanaesthesia and are increasingly used in experimental animal studies. In translational models, the pig has advantages compared to small laboratory animals because of brain anatomy, metabolism, neurophysiological maturation, and cerebral haemodynamics. However, reported effects of propofol and remifentanil on cerebral perfusion and oxygenation in pigs have not been reviewed. An electronic search identified 99 articles in English. Title and abstract screening selected 29 articles for full-text evaluation of which 19 were excluded with reasons. Of the 10 peer-reviewed articles included for review, only three had propofol or remifentanil anaesthesia as the primary study objective and only two directly investigated the effect of anaesthesia on cerebral perfusion and oxygenation (CPO). The evidence evaluated in this systematic review is limited, not focused on propofol and remifentanil and possibly influenced by factors of potential importance for CPO assessment. In one study of healthy pigs, CPO measures were within normal ranges following propofol-remifentanil anaesthesia, and addition of a single remifentanil bolus did not affect regional cerebral oxygen saturation (rSO2). Even though the pool of evidence suggests that propofol and remifentanil alone or in combination have limited effects on CPO in healthy pigs, confirmative evidence is lacking.

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“…15,25,26 In addition to evaluating the efficacy of IO hydroxocobalamin, we used near infrared spectroscopy, which is a continuous noninvasive assessment of tissue perfusion and oxygen delivery in trauma care and hemorrhage. 27 NIRS has shown benefit in emergency settings, but use of NIRS has not been evaluated for chemical-induced shock and more specifically with cyanide toxicity. In our study, NIRS generally paralleled MAP, but was not predictive of hypotension.…”

Section: Discussionmentioning

confidence: 99%

Intraosseous Versus Intravenous Infusion of Hydroxocobalamin for the Treatment Of Acute Severe Cyanide Toxicity in a Swine Model

Bebarta

Pitotti

Boudreau

et al. 2014

Academic Emergency Medicine

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Objectives: Easily administrated cyanide antidotes are needed for first responders, military troops, and emergency department staff after cyanide exposure in mass casualty incidents or due to smoke inhalation during fires involving many victims. Hydroxocobalamin has proven to be an effective antidote, but cannot be given intramuscularly because the volume of diluent needed is too large. Thus, intraosseous (IO) infusion may be an alternative, as it is simple and has been recommended for the administration of other resuscitation drugs. The primary objective of this study was to compare the efficacy of IO delivery of hydroxocobalamin to intravenous (IV) injection for the management of acute cyanide toxicity in a well-described porcine model. Methods:Twenty-four swine (45 to 55 kg) were anesthetized, intubated, and instrumented with continuous mean arterial pressure (MAP) and cardiac output monitoring. Cyanide was continuously infused until severe hypotension (50% of baseline MAP), followed by IO or IV hydroxocobalamin treatment. Animals were randomly assigned to receive IV (150 mg/kg) or IO (150 mg/kg) hydroxocobalamin and monitored for 60 minutes after start of antidotal infusion. The primary outcome measure was the change in MAP after antidotal treatment from onset of hypotension (time zero) to 60 minutes. A sample size of 12 animals per group was determined by group size analysis based on power of 80% to detect a one standard deviation of the mean MAP between the groups with an alpha of 0.05. Whole blood cyanide, lactate, pH, nitrotyrosine (nitric oxide marker) levels, cerebral and renal near infrared spectrometry (NIRS) oxygenation, and inflammatory markers were also measured. Repeated-measures analysis of variance was used to determine statistically significant changes between groups over time.Results: At baseline and at the point of hypotension, physiologic parameters were similar between groups. At the conclusion of the study, 10 out of 12 animals in the IV group and 10 out of 12 in IO group survived (p = 1.0). Both groups demonstrated a similar return to baseline MAP (p = 0.997). Cardiac output, oxygen saturation, and systemic vascular resistance were also found to be similar between groups (p > 0.4), and no difference was detected between bicarbonate, pH, and lactate levels (p > 0.8). Cyanide levels were undetectable after the hydroxocobalamin infusion throughout the study in both groups (p = 1.0). Cerebral and renal NIRS oxygenation decreased in parallel to MAP during cyanide infusion and increased after antidote infusion in both groups. Serum nitrotyrosine increased during cyanide infusion in all animals and then decreased in both study arms after hydroxocobalamin infusion (p > 0.5). Serum cytokines increased starting at cyanide infusion and no difference was detected between groups (tumor necrosis factor-a, interleukin [IL]-1b, IL-6, and IL-10).

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Continuous measurement of cerebral oxygen saturation (rSO2) for assessment of cardiovascular status during hemorrhagic shock in a swine model

Cited by 10 publications

References 29 publications

Effect of hemorrhage rate on early hemodynamic responses in conscious sheep

Effect of hemorrhage rate on early hemodynamic responses in conscious sheep

Effect of propofol and remifentanil on cerebral perfusion and oxygenation in pigs: a systematic review

Intraosseous Versus Intravenous Infusion of Hydroxocobalamin for the Treatment Of Acute Severe Cyanide Toxicity in a Swine Model

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