Inhalant anesthesia induces dose-dependent cardiovascular depression, but whether fluid responsiv... more Inhalant anesthesia induces dose-dependent cardiovascular depression, but whether fluid responsiveness is differentially influenced by the inhalant agent and plasma volemia remains unknown. The aim of this study was to compare the effects of isoflurane, sevoflurane and desflurane on pulse pressure variation and stroke volume variation in pigs undergoing hemorrhage. METHODS: Twenty-five pigs were randomly anesthetized with isoflurane, sevoflurane or desflurane. Hemodynamic and echocardiographic data were registered sequentially at minimum alveolar concentrations of 1.00 (M1), 1.25 (M2), and 1.00 (M3). Then, following withdrawal of 30% of the estimated blood volume, these data were registered at a minimum alveolar concentrations of 1.00 (M4) and 1.25 (M5). RESULTS: The minimum alveolar concentration increase from 1.00 to 1.25 (M2) decreased the cardiac index and increased the central venous pressure, but only modest changes in mean arterial pressure, pulse pressure variation and stroke volume variation were observed in all groups from M1 to M2. A significant decrease in mean arterial pressure was only observed with desflurane. Following blood loss (M4), pulse pressure variation, stroke volume variation and central venous pressure increased (po0.001) and mean arterial pressure decreased in all groups. Under hypovolemia, the cardiac index decreased with the increase of anesthesia depth in a similar manner in all groups. CONCLUSION: The effects of desflurane, sevoflurane and isoflurane on pulse pressure variation and stroke volume variation were not different during normovolemia or hypovolemia.
Objective To evaluate the cyclooxygenases (COX) inhibition, adverse effects and analgesic efficac... more Objective To evaluate the cyclooxygenases (COX) inhibition, adverse effects and analgesic efficacy of dipyrone or meloxicam in cats undergoing elective ovariohysterectomy. Study design Prospective, blinded, randomized, clinical study. Animals A total of 30 healthy young cats. Methods The cats were randomly assigned to three postoperative groups: D25 (dipyrone 25 mg kg À1 every 24 hours), D12.5 (dipyrone 12.5 mg kg À1 every 12 hours) and M (meloxicam 0.1 mg kg À1 every 24 hours). In the first 24 hours, the drugs were administered intravenously (IV), and then orally for 6 (dipyrone) or 3 days (meloxicam). Prostanoids thromboxane B 2 and prostaglandin E 2 concentrations served as indicators of COX activity and, with physiological variables and pain and sedation scores, were measured for 24 hours after first analgesic administration. Rescue analgesia (tramadol, 2 mg kg À1 IV) was provided if Glasgow feline composite measure pain scale (CMPS-Feline) !5. Laboratory tests included symmetric dimethylarginine and adverse effects were evaluated regularly up to 7 and 10 days after surgery, respectively. Parametric and nonparametric data were analyzed with two-way ANOVA and Kruskal-Wallis tests, respectively (p < 0.05). Results In the first half hour after analgesic administration, COX-1 activity was close to zero and remained significantly lower than before drug administration for 24 hours in all groups. The inhibition of COX-2 activity was significant for 30 minutes in all groups and up to 4 hours in group M. No alterations in laboratory tests or significant adverse effects were observed. Pain scores and need for rescue analgesia did not differ statistically among groups. Conclusions Dipyrone at both doses and meloxicam provided a nonselective inhibition of COX-1 and-2 activities and effective analgesia without causing significant adverse effects or laboratory tests alterations. Clinical relevance Dipyrone at both doses provides equally effective analgesia without causing adverse effects in cats undergoing ovariohysterectomy.
Despite the fact that hemodilution has been used in man for more than 4 decades, there are still ... more Despite the fact that hemodilution has been used in man for more than 4 decades, there are still many controversies related to the selection of the target hematocrit, kind of fluid to maintain normovolemia, anesthetics, and the hemodynamic responses verified in clinical studies. For these reasons, many experimental studies have been conducted in order to elucidate these factors. In this chapter we have reviewed some of these topics and the different experimental models employed and their results.
Background: Peripheral hematopoietic stem cell (HSC) collections are needed for autologous hemato... more Background: Peripheral hematopoietic stem cell (HSC) collections are needed for autologous hematopoietic stem cell transplantation (HSCT). Since 2015, our institution has utilized a secondary chamber mononuclear cell (MNC) protocol on the Spectra Optia apheresis system. Recently, a new continuous mononuclear collection protocol (CMNC) was developed for the same device. As there is limited data available regarding the use of the CMNC protocol in children, we compared collection efficiency (CE2), side effects, and clinical feasibility between the two protocols in patients <18 years old. Study Design and Methods: We prospectively collected clinical, laboratory, and technical collection data from HSC collection procedures performed with the Spectra Optia apheresis system utilizing the CMNC protocol. Data were compared to retrospectively collected data utilizing the MNC protocol. Data collection included donor demographics, precollection peripheral CD34+ cell counts, total CD34+ cells collected, collection efficiency, side effects, and collection product characteristics. Results: A total of 96 HSC collection procedures were performed on 79 pediatric patients utilizing either the MNC (61 patients) or CMNC (18 patients) protocol. The collection efficiencies were comparable between MNC and CMNC cohorts (52.9% vs 54.9%, P = 0.711). Platelet loss was significantly lower in the CMNC cohort (P = 0.002), especially in children weighing <15 kg. Product volumes were higher with CMNC. No significant collection-related side effects were noted with either protocol. Conclusions: MNC and CMNC protocols have comparable collection efficiencies and are both feasible and safe for the use in children. Centers may choose between the methods depending on clinical needs.
Hemorrhagic shock (HS), a major cause of trauma-related mortality, is mainly treated by crystallo... more Hemorrhagic shock (HS), a major cause of trauma-related mortality, is mainly treated by crystalloid fluid administration, typically with lactated Ringer’s (LR). Despite beneficial hemodynamic effects, such as the restoration of mean arterial pressure (MAP), LR administration has major side effects, including organ damage due to edema. One strategy to avoid such effects is pre-hospitalization intravenous administration of the potent vasoconstrictor terlipressin, which can restore hemodynamic stability/homeostasis and has anti-inflammatory effects. Wistar rats were subjected to HS for 60 min, at a target MAP of 30–40 mmHg, thereafter being allocated to receive LR infusion at 3 times the volume of the blood withdrawn (liberal fluid management); at 2 times the volume (conservative fluid management), plus terlipressin (10 µg/100 g body weight); and at an equal volume (conservative fluid management), plus terlipressin (10 µg/100 g body weight). A control group comprised rats not subjected...
To determine whether dexmedetomidine aggravates hemodynamic, metabolic variables, inflammatory ma... more To determine whether dexmedetomidine aggravates hemodynamic, metabolic variables, inflammatory markers, and microcirculation in experimental septic shock. Methods: Twenty-four pigs randomized into: Sham group (n = 8), received saline; Shock group (n = 8), received an intravenous infusion of Escherichia coli O55 (3 × 10 9 cells/mL, 0.75 mL/kg, 1 hour); Dex-Shock group (n = 8), received bacteria and intravenous dexmedetomidine (bolus 0.5 mcg/kg followed by 0.7 mcg/kg/h). Fluid therapy and/or norepinephrine were administered to maintain a mean arterial pressure > 65 mmHg. Hemodynamic, metabolic, oxygenation, inflammatory markers, and microcirculation were assessed at baseline, at the end of bacterial infusion, and after 60, 120, 180, and 240 minutes. Results: Compared to Shock group, Dex-Shock group presented a significantly increased oxygen extraction ratio at T180 (23.1 ± 9.7 vs. 32.5 ± 9.2%, P = 0.0220), decreased central venous pressure at T120 (11.6 ± 1 vs. 9.61 ± 1.2 mmHg, P = 0.0214), mixed-venous oxygen saturation at T180 (72.9 ± 9.6 vs. 63.5 ± 9.2%, P = 0.026), and increased plasma lactate (3.7 ± 0.5 vs. 5.5 ± 1 mmol/L, P = 0.003). Despite the Dex-Shock group having a better sublingual vessel density at T240 (12.5 ± 0.4 vs. 14.4 ± 0.3 mL/m 2 ; P = 0.0003), sublingual blood flow was not different from that in the Shock group (2.4 ± 0.2 vs. 2.4 ± 0.1 mL/kg, P = 0.4418). Conclusions: Dexmedetomidine did not worsen the hemodynamic, metabolic, inflammatory, or sublingual blood flow disorders resulting from septic shock. Despite inducing a better sublingual vessel density, dexmedetomidine initially and transitorily increased the mismatch between oxygen supply and demand.
ObjectiveThis study aimed to evaluate lung overinflation at different airway inspiratory pressure... more ObjectiveThis study aimed to evaluate lung overinflation at different airway inspiratory pressure levels using computed tomography in cats undergoing general anesthesia.Study DesignProspective laboratory study.AnimalsA group of 17 healthy male cats, aged 1.9–4.5 years and weighing 3.5 ± 0.5 kg.MethodsSeventeen adult male cats were ventilated in pressure-controlled mode with airway pressure stepwise increased from 5 to 15 cmH2O in 2 cmH2O steps every 5 min and then stepwise decreased. The respiratory rate was set at 15 movements per min and end-expiratory pressure at zero (ZEEP). After 5 min in each inspiratory pressure step, a 4 s inspiratory pause was performed to obtain a thoracic juxta-diaphragmatic single slice helical CT image and to collect respiratory mechanics data and an arterial blood sample. Lung parenchyma aeration was defined as overinflated, normally-aerated, poorly-aerated, and non-aerated according to the CT attenuation number (−1,000 to −900 HU, −900 to −500 HU, −50...
Brazilian Journal of Anesthesiology (English Edition), 2021
Background: Sepsis and septic shock still represent great challenges in critical care medicine. S... more Background: Sepsis and septic shock still represent great challenges in critical care medicine. Sildenafil has been largely used in the treatment of pulmonary arterial hypertension, but its effects in sepsis are unknown. The aim of this study was to investigate the hypothesis that sildenafil can attenuate endotoxin-induced pulmonary hypertension in a porcine model of endotoxemia. Methods: Twenty pigs were randomly assigned to Control group (n = 10), which received saline solution; or to Sildenafil group (n = 10), which received sildenafil orally (100 mg). After 30 minutes, both groups were submitted to endotoxemia with intravenous bacterial lipopolysaccharide endotoxin (LPS) infusion (4 g.kg-1 .h-1) for 180 minutes. We evaluated hemodynamic and oxygenation functions, and also lung histology and plasma cytokine (TNF␣, IL-1, IL6, and IL10) and troponin I response. Results: Significant hemodynamic alterations were observed after 30 minutes of LPS continuous infusion, mainly in pulmonary arterial pressure (from Baseline 19 ± 2 mmHg to LPS30 52 ± 4 mmHg, p < 0.05). There was also a significant decrease in PaO 2 /FiO 2 (from Baseline 411 ± 29 to LPS180 334 ± 49, p < 0.05). Pulmonary arterial pressure was significantly lower in the Sildenafil group (35 ± 4 mmHg at LPS30, p < 0.05). The Sildenafil group also presented lower values of systemic arterial pressure. Sildenafil maintained oxygenation with higher PaO 2 /FiO 2 and lower oxygen extraction rate than Control group but had no effect on intrapulmonary shunt. All cytokines and troponin increased after LPS infusion in both groups similarly.
Hemorrhagic shock (HS), a major cause of trauma-related mortality, is mainly treated by crystallo... more Hemorrhagic shock (HS), a major cause of trauma-related mortality, is mainly treated by crystalloid fluid administration, typically with lactated Ringer’s (LR). Despite beneficial hemodynamic effects, such as the restoration of mean arterial pressure (MAP), LR administration has major side effects, including organ damage due to edema. One strategy to avoid such effects is pre-hospitalization intravenous administration of the potent vasoconstrictor terlipressin, which can restore hemodynamic stability/homeostasis and has anti-inflammatory effects. Wistar rats were subjected to HS for 60 min, at a target MAP of 30–40 mmHg, thereafter being allocated to receive LR infusion at 3 times the volume of the blood withdrawn; at 2 times the volume, plus terlipressin (10 µg/100 g body weight); and at an equal volume, plus terlipressin (10 µg/100 g body weight). A control group comprised rats not subjected to HS and receiving no fluid resuscitation or treatment. At 15 min after fluid resuscitati...
Background Intravenous vancomycin is used to treat ventilator-associated pneumonia caused by meth... more Background Intravenous vancomycin is used to treat ventilator-associated pneumonia caused by methicillin-resistant Staphylococcus aureus, but achieves high rates of failure. Vancomycin nebulization may be efficient to provide high vancomycin lung tissue concentrations. The aim of this study was to compare lung tissue and serum concentrations of vancomycin administered intravenously and by aerosol in mechanically ventilated and anesthetized healthy piglets. Methods Twelve female piglets received a single intravenous dose of vancomycin (15 mg/kg) and were killed 1 (n = 6) or 12 h (n = 6) after the end of administration. Twelve piglets received a single nebulized dose of vancomycin (37.5 mg/kg) and were killed 1 (n = 6) or 12 h (n = 6) after the end of the aerosol administration. In each group, vancomycin lung tissue concentrations were assessed on postmortem lung specimens using high-performance liquid chromatography. Blood samples were collected for serum vancomycin concentration mea...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Objective To evaluate the ability and accuracy of aortic flow velocityetime integral variation (D... more Objective To evaluate the ability and accuracy of aortic flow velocityetime integral variation (DVTI) and peak aortic velocity variation (DVpeak) compared with pulse pressure variation (PPV) to predict fluid responsiveness in mechanically ventilated dogs. Study design Prospective clinical study. Animals A group of 50 mechanically ventilated dogs with spontaneous hypotension during orthopedic or oncologic surgery. Methods Investigations were performed in the surgery room. When mean arterial pressure (MAP) decreased to <65 mmHg, measurements were performed before and after a fluid challenge (lactated Ringer's solution 5 mL kg À1 over 15 minutes). Responders were defined as a change in stroke volume (SV; transesophageal Doppler) !15%. Data were analyzed using paired/unpaired t test or Man-neWhitney/Wilcoxon test when appropriate and receiver operating characteristics (ROC) curves; a p value <0.05 was considered statistically significant. Results After the fluid challenge, 35 (70%) of 50 dogs were responders with significant increases in SV and decreases in PPV; 15 dogs were nonresponders. DVTI and DVpeak correlated with a 15% increase in SV. The optimum cutoff value for PPV was 15.6% (sensitivity, 88%; specificity, 100%), that for DVTI was 10.65% (sensitivity, 65%; specificity, 100%) and that for DVpeak was 10.15% (sensitivity, 80%; specificity, 100%). The area under the ROC curve for PPV was (0.93 ± 0.08) and that for DVpeak was (0.89 ± 0.09), before fluid challenge. The gray zone area spread from 6.15% to 15.6% for PPV (18 dogs), 2.45% to 10.65% for DVTI (22 dogs) and 0.6% to 10.15% for DVpeak (25 dogs). Conclusions When using mechanical ventilation, DVTI and DVpeak predicted fluid responsiveness with the same ability as PPV, based on the area under the ROC curve analysis. However, PPV showed great accuracy demonstrated by a narrower gray zone that included fewer individuals. Clinical relevance DVTI and DVpeak can be used as indices of fluid responsiveness in anesthetized dogs.
Inhalant anesthesia induces dose-dependent cardiovascular depression, but whether fluid responsiv... more Inhalant anesthesia induces dose-dependent cardiovascular depression, but whether fluid responsiveness is differentially influenced by the inhalant agent and plasma volemia remains unknown. The aim of this study was to compare the effects of isoflurane, sevoflurane and desflurane on pulse pressure variation and stroke volume variation in pigs undergoing hemorrhage. METHODS: Twenty-five pigs were randomly anesthetized with isoflurane, sevoflurane or desflurane. Hemodynamic and echocardiographic data were registered sequentially at minimum alveolar concentrations of 1.00 (M1), 1.25 (M2), and 1.00 (M3). Then, following withdrawal of 30% of the estimated blood volume, these data were registered at a minimum alveolar concentrations of 1.00 (M4) and 1.25 (M5). RESULTS: The minimum alveolar concentration increase from 1.00 to 1.25 (M2) decreased the cardiac index and increased the central venous pressure, but only modest changes in mean arterial pressure, pulse pressure variation and stroke volume variation were observed in all groups from M1 to M2. A significant decrease in mean arterial pressure was only observed with desflurane. Following blood loss (M4), pulse pressure variation, stroke volume variation and central venous pressure increased (po0.001) and mean arterial pressure decreased in all groups. Under hypovolemia, the cardiac index decreased with the increase of anesthesia depth in a similar manner in all groups. CONCLUSION: The effects of desflurane, sevoflurane and isoflurane on pulse pressure variation and stroke volume variation were not different during normovolemia or hypovolemia.
Objective To evaluate the cyclooxygenases (COX) inhibition, adverse effects and analgesic efficac... more Objective To evaluate the cyclooxygenases (COX) inhibition, adverse effects and analgesic efficacy of dipyrone or meloxicam in cats undergoing elective ovariohysterectomy. Study design Prospective, blinded, randomized, clinical study. Animals A total of 30 healthy young cats. Methods The cats were randomly assigned to three postoperative groups: D25 (dipyrone 25 mg kg À1 every 24 hours), D12.5 (dipyrone 12.5 mg kg À1 every 12 hours) and M (meloxicam 0.1 mg kg À1 every 24 hours). In the first 24 hours, the drugs were administered intravenously (IV), and then orally for 6 (dipyrone) or 3 days (meloxicam). Prostanoids thromboxane B 2 and prostaglandin E 2 concentrations served as indicators of COX activity and, with physiological variables and pain and sedation scores, were measured for 24 hours after first analgesic administration. Rescue analgesia (tramadol, 2 mg kg À1 IV) was provided if Glasgow feline composite measure pain scale (CMPS-Feline) !5. Laboratory tests included symmetric dimethylarginine and adverse effects were evaluated regularly up to 7 and 10 days after surgery, respectively. Parametric and nonparametric data were analyzed with two-way ANOVA and Kruskal-Wallis tests, respectively (p < 0.05). Results In the first half hour after analgesic administration, COX-1 activity was close to zero and remained significantly lower than before drug administration for 24 hours in all groups. The inhibition of COX-2 activity was significant for 30 minutes in all groups and up to 4 hours in group M. No alterations in laboratory tests or significant adverse effects were observed. Pain scores and need for rescue analgesia did not differ statistically among groups. Conclusions Dipyrone at both doses and meloxicam provided a nonselective inhibition of COX-1 and-2 activities and effective analgesia without causing significant adverse effects or laboratory tests alterations. Clinical relevance Dipyrone at both doses provides equally effective analgesia without causing adverse effects in cats undergoing ovariohysterectomy.
Despite the fact that hemodilution has been used in man for more than 4 decades, there are still ... more Despite the fact that hemodilution has been used in man for more than 4 decades, there are still many controversies related to the selection of the target hematocrit, kind of fluid to maintain normovolemia, anesthetics, and the hemodynamic responses verified in clinical studies. For these reasons, many experimental studies have been conducted in order to elucidate these factors. In this chapter we have reviewed some of these topics and the different experimental models employed and their results.
Background: Peripheral hematopoietic stem cell (HSC) collections are needed for autologous hemato... more Background: Peripheral hematopoietic stem cell (HSC) collections are needed for autologous hematopoietic stem cell transplantation (HSCT). Since 2015, our institution has utilized a secondary chamber mononuclear cell (MNC) protocol on the Spectra Optia apheresis system. Recently, a new continuous mononuclear collection protocol (CMNC) was developed for the same device. As there is limited data available regarding the use of the CMNC protocol in children, we compared collection efficiency (CE2), side effects, and clinical feasibility between the two protocols in patients <18 years old. Study Design and Methods: We prospectively collected clinical, laboratory, and technical collection data from HSC collection procedures performed with the Spectra Optia apheresis system utilizing the CMNC protocol. Data were compared to retrospectively collected data utilizing the MNC protocol. Data collection included donor demographics, precollection peripheral CD34+ cell counts, total CD34+ cells collected, collection efficiency, side effects, and collection product characteristics. Results: A total of 96 HSC collection procedures were performed on 79 pediatric patients utilizing either the MNC (61 patients) or CMNC (18 patients) protocol. The collection efficiencies were comparable between MNC and CMNC cohorts (52.9% vs 54.9%, P = 0.711). Platelet loss was significantly lower in the CMNC cohort (P = 0.002), especially in children weighing <15 kg. Product volumes were higher with CMNC. No significant collection-related side effects were noted with either protocol. Conclusions: MNC and CMNC protocols have comparable collection efficiencies and are both feasible and safe for the use in children. Centers may choose between the methods depending on clinical needs.
Hemorrhagic shock (HS), a major cause of trauma-related mortality, is mainly treated by crystallo... more Hemorrhagic shock (HS), a major cause of trauma-related mortality, is mainly treated by crystalloid fluid administration, typically with lactated Ringer’s (LR). Despite beneficial hemodynamic effects, such as the restoration of mean arterial pressure (MAP), LR administration has major side effects, including organ damage due to edema. One strategy to avoid such effects is pre-hospitalization intravenous administration of the potent vasoconstrictor terlipressin, which can restore hemodynamic stability/homeostasis and has anti-inflammatory effects. Wistar rats were subjected to HS for 60 min, at a target MAP of 30–40 mmHg, thereafter being allocated to receive LR infusion at 3 times the volume of the blood withdrawn (liberal fluid management); at 2 times the volume (conservative fluid management), plus terlipressin (10 µg/100 g body weight); and at an equal volume (conservative fluid management), plus terlipressin (10 µg/100 g body weight). A control group comprised rats not subjected...
To determine whether dexmedetomidine aggravates hemodynamic, metabolic variables, inflammatory ma... more To determine whether dexmedetomidine aggravates hemodynamic, metabolic variables, inflammatory markers, and microcirculation in experimental septic shock. Methods: Twenty-four pigs randomized into: Sham group (n = 8), received saline; Shock group (n = 8), received an intravenous infusion of Escherichia coli O55 (3 × 10 9 cells/mL, 0.75 mL/kg, 1 hour); Dex-Shock group (n = 8), received bacteria and intravenous dexmedetomidine (bolus 0.5 mcg/kg followed by 0.7 mcg/kg/h). Fluid therapy and/or norepinephrine were administered to maintain a mean arterial pressure > 65 mmHg. Hemodynamic, metabolic, oxygenation, inflammatory markers, and microcirculation were assessed at baseline, at the end of bacterial infusion, and after 60, 120, 180, and 240 minutes. Results: Compared to Shock group, Dex-Shock group presented a significantly increased oxygen extraction ratio at T180 (23.1 ± 9.7 vs. 32.5 ± 9.2%, P = 0.0220), decreased central venous pressure at T120 (11.6 ± 1 vs. 9.61 ± 1.2 mmHg, P = 0.0214), mixed-venous oxygen saturation at T180 (72.9 ± 9.6 vs. 63.5 ± 9.2%, P = 0.026), and increased plasma lactate (3.7 ± 0.5 vs. 5.5 ± 1 mmol/L, P = 0.003). Despite the Dex-Shock group having a better sublingual vessel density at T240 (12.5 ± 0.4 vs. 14.4 ± 0.3 mL/m 2 ; P = 0.0003), sublingual blood flow was not different from that in the Shock group (2.4 ± 0.2 vs. 2.4 ± 0.1 mL/kg, P = 0.4418). Conclusions: Dexmedetomidine did not worsen the hemodynamic, metabolic, inflammatory, or sublingual blood flow disorders resulting from septic shock. Despite inducing a better sublingual vessel density, dexmedetomidine initially and transitorily increased the mismatch between oxygen supply and demand.
ObjectiveThis study aimed to evaluate lung overinflation at different airway inspiratory pressure... more ObjectiveThis study aimed to evaluate lung overinflation at different airway inspiratory pressure levels using computed tomography in cats undergoing general anesthesia.Study DesignProspective laboratory study.AnimalsA group of 17 healthy male cats, aged 1.9–4.5 years and weighing 3.5 ± 0.5 kg.MethodsSeventeen adult male cats were ventilated in pressure-controlled mode with airway pressure stepwise increased from 5 to 15 cmH2O in 2 cmH2O steps every 5 min and then stepwise decreased. The respiratory rate was set at 15 movements per min and end-expiratory pressure at zero (ZEEP). After 5 min in each inspiratory pressure step, a 4 s inspiratory pause was performed to obtain a thoracic juxta-diaphragmatic single slice helical CT image and to collect respiratory mechanics data and an arterial blood sample. Lung parenchyma aeration was defined as overinflated, normally-aerated, poorly-aerated, and non-aerated according to the CT attenuation number (−1,000 to −900 HU, −900 to −500 HU, −50...
Brazilian Journal of Anesthesiology (English Edition), 2021
Background: Sepsis and septic shock still represent great challenges in critical care medicine. S... more Background: Sepsis and septic shock still represent great challenges in critical care medicine. Sildenafil has been largely used in the treatment of pulmonary arterial hypertension, but its effects in sepsis are unknown. The aim of this study was to investigate the hypothesis that sildenafil can attenuate endotoxin-induced pulmonary hypertension in a porcine model of endotoxemia. Methods: Twenty pigs were randomly assigned to Control group (n = 10), which received saline solution; or to Sildenafil group (n = 10), which received sildenafil orally (100 mg). After 30 minutes, both groups were submitted to endotoxemia with intravenous bacterial lipopolysaccharide endotoxin (LPS) infusion (4 g.kg-1 .h-1) for 180 minutes. We evaluated hemodynamic and oxygenation functions, and also lung histology and plasma cytokine (TNF␣, IL-1, IL6, and IL10) and troponin I response. Results: Significant hemodynamic alterations were observed after 30 minutes of LPS continuous infusion, mainly in pulmonary arterial pressure (from Baseline 19 ± 2 mmHg to LPS30 52 ± 4 mmHg, p < 0.05). There was also a significant decrease in PaO 2 /FiO 2 (from Baseline 411 ± 29 to LPS180 334 ± 49, p < 0.05). Pulmonary arterial pressure was significantly lower in the Sildenafil group (35 ± 4 mmHg at LPS30, p < 0.05). The Sildenafil group also presented lower values of systemic arterial pressure. Sildenafil maintained oxygenation with higher PaO 2 /FiO 2 and lower oxygen extraction rate than Control group but had no effect on intrapulmonary shunt. All cytokines and troponin increased after LPS infusion in both groups similarly.
Hemorrhagic shock (HS), a major cause of trauma-related mortality, is mainly treated by crystallo... more Hemorrhagic shock (HS), a major cause of trauma-related mortality, is mainly treated by crystalloid fluid administration, typically with lactated Ringer’s (LR). Despite beneficial hemodynamic effects, such as the restoration of mean arterial pressure (MAP), LR administration has major side effects, including organ damage due to edema. One strategy to avoid such effects is pre-hospitalization intravenous administration of the potent vasoconstrictor terlipressin, which can restore hemodynamic stability/homeostasis and has anti-inflammatory effects. Wistar rats were subjected to HS for 60 min, at a target MAP of 30–40 mmHg, thereafter being allocated to receive LR infusion at 3 times the volume of the blood withdrawn; at 2 times the volume, plus terlipressin (10 µg/100 g body weight); and at an equal volume, plus terlipressin (10 µg/100 g body weight). A control group comprised rats not subjected to HS and receiving no fluid resuscitation or treatment. At 15 min after fluid resuscitati...
Background Intravenous vancomycin is used to treat ventilator-associated pneumonia caused by meth... more Background Intravenous vancomycin is used to treat ventilator-associated pneumonia caused by methicillin-resistant Staphylococcus aureus, but achieves high rates of failure. Vancomycin nebulization may be efficient to provide high vancomycin lung tissue concentrations. The aim of this study was to compare lung tissue and serum concentrations of vancomycin administered intravenously and by aerosol in mechanically ventilated and anesthetized healthy piglets. Methods Twelve female piglets received a single intravenous dose of vancomycin (15 mg/kg) and were killed 1 (n = 6) or 12 h (n = 6) after the end of administration. Twelve piglets received a single nebulized dose of vancomycin (37.5 mg/kg) and were killed 1 (n = 6) or 12 h (n = 6) after the end of the aerosol administration. In each group, vancomycin lung tissue concentrations were assessed on postmortem lung specimens using high-performance liquid chromatography. Blood samples were collected for serum vancomycin concentration mea...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Objective To evaluate the ability and accuracy of aortic flow velocityetime integral variation (D... more Objective To evaluate the ability and accuracy of aortic flow velocityetime integral variation (DVTI) and peak aortic velocity variation (DVpeak) compared with pulse pressure variation (PPV) to predict fluid responsiveness in mechanically ventilated dogs. Study design Prospective clinical study. Animals A group of 50 mechanically ventilated dogs with spontaneous hypotension during orthopedic or oncologic surgery. Methods Investigations were performed in the surgery room. When mean arterial pressure (MAP) decreased to <65 mmHg, measurements were performed before and after a fluid challenge (lactated Ringer's solution 5 mL kg À1 over 15 minutes). Responders were defined as a change in stroke volume (SV; transesophageal Doppler) !15%. Data were analyzed using paired/unpaired t test or Man-neWhitney/Wilcoxon test when appropriate and receiver operating characteristics (ROC) curves; a p value <0.05 was considered statistically significant. Results After the fluid challenge, 35 (70%) of 50 dogs were responders with significant increases in SV and decreases in PPV; 15 dogs were nonresponders. DVTI and DVpeak correlated with a 15% increase in SV. The optimum cutoff value for PPV was 15.6% (sensitivity, 88%; specificity, 100%), that for DVTI was 10.65% (sensitivity, 65%; specificity, 100%) and that for DVpeak was 10.15% (sensitivity, 80%; specificity, 100%). The area under the ROC curve for PPV was (0.93 ± 0.08) and that for DVpeak was (0.89 ± 0.09), before fluid challenge. The gray zone area spread from 6.15% to 15.6% for PPV (18 dogs), 2.45% to 10.65% for DVTI (22 dogs) and 0.6% to 10.15% for DVpeak (25 dogs). Conclusions When using mechanical ventilation, DVTI and DVpeak predicted fluid responsiveness with the same ability as PPV, based on the area under the ROC curve analysis. However, PPV showed great accuracy demonstrated by a narrower gray zone that included fewer individuals. Clinical relevance DVTI and DVpeak can be used as indices of fluid responsiveness in anesthetized dogs.
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