Background The hallmark of sickle cell disease (SCD) is erythrocyte sickling during deoxygenation... more Background The hallmark of sickle cell disease (SCD) is erythrocyte sickling during deoxygenation of the abnormal hemoglobin S (HbS). When HbS is deoxygenated, it aggregates into polymers, resulting in distortion of the erythrocyte structure, producing microvascular thrombosis and ischemia. The transgenic SAD mouse produces three types of human hemoglobin: S, Antilles, and D-Punjab (HbSAD) and provides an animal model for SCD. We studied the effects of nitric oxide (NO) breathing at various doses and time regimens in the presence of severe hypoxia (6% oxygen) using the SAD mouse model. Methods Age- and sex-matched control and SAD mice were exposed to 6% oxygen breathing in an environmental chamber and assessed for survival up to 1 h. Animals received different inhaled NO concentrations before and/or during hypoxia. Blood was obtained to evaluate the oxyhemoglobin dissociation curve and measure methemoglobinemia. Results Pretreatment by breathing NO at 20 ppm by volume in air for 30 ...
We study the effect on Intralipid on pulmonary circulation. A 10% infusion of Intralipid was admi... more We study the effect on Intralipid on pulmonary circulation. A 10% infusion of Intralipid was administered at a dose of 0.5/kg in 14 isolated rabbit lungs in which constant blood flow infusion was carried out principally in zone 3. The liquid filtration rate (LFR) and the mean pressure of the pulmonary artery were measured. A constant increase of mean pressure of the pulmonary artery was observed following the infusion (from 12.32 +/- 3.66 cm of H2O to 39.92 +/- 07.68 cmH2O (p < 0.01) which was associated to a significant increase in the rate of liquid filtration (from 0.018 +/- 0.01 g/min to 0.198 +/- 0.04 g/min; p < 0.01). The administration of Intralipid produces a statistically significant increase of mean pressure of the pulmonary artery and the rate of liquid filtration. This is probably caused by vasoconstriction due to metabolic changes produced by Intralipid on pulmonary circulation.
Background Adjuvant regional anesthesia is often selected for patients or procedures with high ri... more Background Adjuvant regional anesthesia is often selected for patients or procedures with high risk of pulmonary complications after general anesthesia. The benefit of adjuvant regional anesthesia to reduce postoperative pulmonary complications remains uncertain. In a prospective observational multicenter study, patients scheduled for non-cardiothoracic surgery with at least one postoperative pulmonary complication surprisingly received adjuvant regional anesthesia more frequently than those with no complications. We hypothesized that, after adjusting for surgical and patient complexity variables, the incidence of postoperative pulmonary complications would not be associated with adjuvant regional anesthesia. Methods We performed a secondary analysis of a prospective observational multicenter study including 1202 American Society of Anesthesiologists physical status 3 patients undergoing non-cardiothoracic surgery. Patients were classified as receiving either adjuvant regional anest...
We tested the importance of aerobic metabolism to human running speed directly by altering inspir... more We tested the importance of aerobic metabolism to human running speed directly by altering inspired oxygen concentrations and comparing the maximal speeds attained at different rates of oxygen uptake. Under both normoxic (20.93% O2) and hypoxic (13.00% O2) conditions, four fit adult men completed 15 all-out sprints lasting from 15 to 180 s as well as progressive, discontinuous treadmill tests to determine maximal oxygen uptake and the metabolic cost of steady-state running. Maximal aerobic power was lower by 30% (1.00 ± 0.15 vs. 0.77 ± 0.12 ml O2 ⋅ kg−1 ⋅ s−1) and sprinting rates of oxygen uptake by 12–25% under hypoxic vs. normoxic conditions while the metabolic cost of submaximal running was the same. Despite reductions in the aerobic energy available for sprinting under hypoxic conditions, our subjects were able to run just as fast for sprints of up to 60 s and nearly as fast for sprints of up to 120 s. This was possible because rates of anaerobic energy release, estimated from o...
Acta physiologica, pharmacologica et therapeutica latinoamericana : organo de la Asociacion Latinoamericana de Ciencias Fisiologicas y [de] la Asociacion Latinoamericana de Farmacologia, 1992
The contribution of cyclo-oxygenase and 5-lipoxygenase metabolites on hemodynamics and oedema for... more The contribution of cyclo-oxygenase and 5-lipoxygenase metabolites on hemodynamics and oedema formation was investigated in 21 isolated rabbit lungs after a 10 min Oleic Acid (OA) infusion, by recording the changes on Fluid Filtration Rate (FFR) and Pulmonary Artery Pressure (PAP). Lungs (n = 7) were pre-treated with indomethacin (cyclo-oxygenase inhibitor) 50 min prior to OA or with Diethylcarbamazine (5-lipoxygenase inhibitor) (n = 7) or not pre-treated at all (control group, n = 7). The FFR in the indomethacin group was significantly greater than in the control and Diethylcarbamazine (DEC) groups 12 min after OA (7.6 +/- 2.3 mg.min-1 vs. 2.3 +/- 0.8 mg.min-1 and 0.96 +/- 0.8 mg.min-1 respectively) (P < 0.01). The FFR in the control lungs 20 min after OA was significantly greater than the corresponding DEC value (4.2 +/- 0.5 mg.min-1 vs. 1.6 +/- 1.0 mg.min-1) (P < 0.01). Mean Pulmonary Artery Pressure (MPAP) increased both in control and indomethacin groups (16.0 +/- 2.0 Tor...
Perioperative management of a patient with ischemic heart disease with coexisting abdominal aorti... more Perioperative management of a patient with ischemic heart disease with coexisting abdominal aortic aneurysm and pheochromocytoma creates a difficult management dilemma, and surgical intervention in these patients carries a significant risk. The state of catecholamine excess and various other coexisting factors can lead to simultaneous occurrence of abdominal aortic aneurysm and pheocromocytoma. The purpose of this report is to present an integrated approach to the management of concomitant abdominal aortic aneurysm and pheochromocytoma, where a combined surgical approach in addressing these two lesions was preferable due to patient comorbidities and surgical implications without significant complication.
The effects of hypothermic perfusion have been studied by using different perfusates in 24 isolat... more The effects of hypothermic perfusion have been studied by using different perfusates in 24 isolated rabbit lung preparations, divided into three groups: G1, perfused with blood (hematocrit of 10%) and G2 and G3, perfused with erythrocyte-free plasma plus 6% protein in saline. In both G1 and G2 groups left atrial pressures were kept below airway pressure (Zone II conditions), and in G3 it was higher than airway pressure (Zone III conditions). Perfusate flow, pulmonary artery pressure, pulmonary vascular resistance, left atrial pressure, fluid filtration rate, colloid osmotic pressure and temperature were not different (p > 0.1) between G1 and G2 at the beginning of the experiments. Lowering perfusate temperature from 38 degrees C to 28 degrees C produced a significant increase in pulmonary artery pressure and pulmonary vascular resistance in G1 but they decreased in G2 lungs (p < 0.05). Fluid filtration rate increased in both groups during hypothermia. These responses were not ...
Abdominal compartment syndrome can result from many different causes. We present a case where thi... more Abdominal compartment syndrome can result from many different causes. We present a case where this dangerous syndrome occurred in the operating room during a transurethral resection of a bladder tumor. It was initially recognized by an elevation in the peak inspiratory pressure. We report the typical physiologic changes that occur with this syndrome and its treatment options.
Background The hallmark of sickle cell disease (SCD) is erythrocyte sickling during deoxygenation... more Background The hallmark of sickle cell disease (SCD) is erythrocyte sickling during deoxygenation of the abnormal hemoglobin S (HbS). When HbS is deoxygenated, it aggregates into polymers, resulting in distortion of the erythrocyte structure, producing microvascular thrombosis and ischemia. The transgenic SAD mouse produces three types of human hemoglobin: S, Antilles, and D-Punjab (HbSAD) and provides an animal model for SCD. We studied the effects of nitric oxide (NO) breathing at various doses and time regimens in the presence of severe hypoxia (6% oxygen) using the SAD mouse model. Methods Age- and sex-matched control and SAD mice were exposed to 6% oxygen breathing in an environmental chamber and assessed for survival up to 1 h. Animals received different inhaled NO concentrations before and/or during hypoxia. Blood was obtained to evaluate the oxyhemoglobin dissociation curve and measure methemoglobinemia. Results Pretreatment by breathing NO at 20 ppm by volume in air for 30 ...
We study the effect on Intralipid on pulmonary circulation. A 10% infusion of Intralipid was admi... more We study the effect on Intralipid on pulmonary circulation. A 10% infusion of Intralipid was administered at a dose of 0.5/kg in 14 isolated rabbit lungs in which constant blood flow infusion was carried out principally in zone 3. The liquid filtration rate (LFR) and the mean pressure of the pulmonary artery were measured. A constant increase of mean pressure of the pulmonary artery was observed following the infusion (from 12.32 +/- 3.66 cm of H2O to 39.92 +/- 07.68 cmH2O (p < 0.01) which was associated to a significant increase in the rate of liquid filtration (from 0.018 +/- 0.01 g/min to 0.198 +/- 0.04 g/min; p < 0.01). The administration of Intralipid produces a statistically significant increase of mean pressure of the pulmonary artery and the rate of liquid filtration. This is probably caused by vasoconstriction due to metabolic changes produced by Intralipid on pulmonary circulation.
Background Adjuvant regional anesthesia is often selected for patients or procedures with high ri... more Background Adjuvant regional anesthesia is often selected for patients or procedures with high risk of pulmonary complications after general anesthesia. The benefit of adjuvant regional anesthesia to reduce postoperative pulmonary complications remains uncertain. In a prospective observational multicenter study, patients scheduled for non-cardiothoracic surgery with at least one postoperative pulmonary complication surprisingly received adjuvant regional anesthesia more frequently than those with no complications. We hypothesized that, after adjusting for surgical and patient complexity variables, the incidence of postoperative pulmonary complications would not be associated with adjuvant regional anesthesia. Methods We performed a secondary analysis of a prospective observational multicenter study including 1202 American Society of Anesthesiologists physical status 3 patients undergoing non-cardiothoracic surgery. Patients were classified as receiving either adjuvant regional anest...
We tested the importance of aerobic metabolism to human running speed directly by altering inspir... more We tested the importance of aerobic metabolism to human running speed directly by altering inspired oxygen concentrations and comparing the maximal speeds attained at different rates of oxygen uptake. Under both normoxic (20.93% O2) and hypoxic (13.00% O2) conditions, four fit adult men completed 15 all-out sprints lasting from 15 to 180 s as well as progressive, discontinuous treadmill tests to determine maximal oxygen uptake and the metabolic cost of steady-state running. Maximal aerobic power was lower by 30% (1.00 ± 0.15 vs. 0.77 ± 0.12 ml O2 ⋅ kg−1 ⋅ s−1) and sprinting rates of oxygen uptake by 12–25% under hypoxic vs. normoxic conditions while the metabolic cost of submaximal running was the same. Despite reductions in the aerobic energy available for sprinting under hypoxic conditions, our subjects were able to run just as fast for sprints of up to 60 s and nearly as fast for sprints of up to 120 s. This was possible because rates of anaerobic energy release, estimated from o...
Acta physiologica, pharmacologica et therapeutica latinoamericana : organo de la Asociacion Latinoamericana de Ciencias Fisiologicas y [de] la Asociacion Latinoamericana de Farmacologia, 1992
The contribution of cyclo-oxygenase and 5-lipoxygenase metabolites on hemodynamics and oedema for... more The contribution of cyclo-oxygenase and 5-lipoxygenase metabolites on hemodynamics and oedema formation was investigated in 21 isolated rabbit lungs after a 10 min Oleic Acid (OA) infusion, by recording the changes on Fluid Filtration Rate (FFR) and Pulmonary Artery Pressure (PAP). Lungs (n = 7) were pre-treated with indomethacin (cyclo-oxygenase inhibitor) 50 min prior to OA or with Diethylcarbamazine (5-lipoxygenase inhibitor) (n = 7) or not pre-treated at all (control group, n = 7). The FFR in the indomethacin group was significantly greater than in the control and Diethylcarbamazine (DEC) groups 12 min after OA (7.6 +/- 2.3 mg.min-1 vs. 2.3 +/- 0.8 mg.min-1 and 0.96 +/- 0.8 mg.min-1 respectively) (P < 0.01). The FFR in the control lungs 20 min after OA was significantly greater than the corresponding DEC value (4.2 +/- 0.5 mg.min-1 vs. 1.6 +/- 1.0 mg.min-1) (P < 0.01). Mean Pulmonary Artery Pressure (MPAP) increased both in control and indomethacin groups (16.0 +/- 2.0 Tor...
Perioperative management of a patient with ischemic heart disease with coexisting abdominal aorti... more Perioperative management of a patient with ischemic heart disease with coexisting abdominal aortic aneurysm and pheochromocytoma creates a difficult management dilemma, and surgical intervention in these patients carries a significant risk. The state of catecholamine excess and various other coexisting factors can lead to simultaneous occurrence of abdominal aortic aneurysm and pheocromocytoma. The purpose of this report is to present an integrated approach to the management of concomitant abdominal aortic aneurysm and pheochromocytoma, where a combined surgical approach in addressing these two lesions was preferable due to patient comorbidities and surgical implications without significant complication.
The effects of hypothermic perfusion have been studied by using different perfusates in 24 isolat... more The effects of hypothermic perfusion have been studied by using different perfusates in 24 isolated rabbit lung preparations, divided into three groups: G1, perfused with blood (hematocrit of 10%) and G2 and G3, perfused with erythrocyte-free plasma plus 6% protein in saline. In both G1 and G2 groups left atrial pressures were kept below airway pressure (Zone II conditions), and in G3 it was higher than airway pressure (Zone III conditions). Perfusate flow, pulmonary artery pressure, pulmonary vascular resistance, left atrial pressure, fluid filtration rate, colloid osmotic pressure and temperature were not different (p > 0.1) between G1 and G2 at the beginning of the experiments. Lowering perfusate temperature from 38 degrees C to 28 degrees C produced a significant increase in pulmonary artery pressure and pulmonary vascular resistance in G1 but they decreased in G2 lungs (p < 0.05). Fluid filtration rate increased in both groups during hypothermia. These responses were not ...
Abdominal compartment syndrome can result from many different causes. We present a case where thi... more Abdominal compartment syndrome can result from many different causes. We present a case where this dangerous syndrome occurred in the operating room during a transurethral resection of a bladder tumor. It was initially recognized by an elevation in the peak inspiratory pressure. We report the typical physiologic changes that occur with this syndrome and its treatment options.
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Papers by Ricardo martinez-ruiz