ACURÁCIA DOS MÉTODOS OSCILOMÉTRICO (PETMAP®) E DOPPLER PARA AFERIÇÃO INDIRETA DA PRESSÃO ARTERIAL EM CORDEIROS

A fisiologia neonatal possui peculiaridades inerentes à faixa etária. O objetivo do estudo foi monitorar a pressão arterial sistêmica de cordeiros durante o período neonatal. Foram usados 20 cordeiros da raça Ile de France, a partir do nascimento e aos sete, 14, 21, 28 e 35 dias de vida. Os parâmetros analisados foram: frequência cardíaca (FC), pressão arterial sistólica (PAS), diastólica (PAD) e média (PAM) pelo método oscilométrico petMAP®, e PAS com Doppler. Também foi realizada a pressão invasiva para validar os métodos indiretos obtendo a média de 101,52 ± 12,04 mmHg. As médias utilizando o petMAP® foram: FC (156,38 ± 37,46 bpm); PAD (63,80 ± 11,14 mmHg); PAM   (81,58 ± 11,83 mmHg); PAS (112,48 ±15,68 mmHg) e PAS (90,27 ± 12,11 mmHg) com Doppler. Houve diferença significativa na FC e pressão arterial entre os momentos analisados. Os métodos indiretos diferiram entre si em 12,30 mmHg (superestimação de 11%). Comparando com a invasiva, os dois métodos superestimaram os valores da PAS em 4% e 16%, respectivamente, para Doppler e petMAP®. Os resultados mostraram que o método Doppler estabeleceu boa relação com a invasiva, sendo útil para aferição da PAS. O método oscilométrico necessita de maiores estudos para sua utilização em pequenos ruminantes. Palavras-chave: Doppler; oscilométrico; ovinos; período neonatal; pressão arterial sistêmica

Efeitos da adrenomodulina no tratamento da hipertensão pulmonar induzida por microesferas em ovinos

Accumulating evidence suggests that pulmonary vasoconstriction drives many of the haemodynamic disorders found in acute pulmonary embolism (APE). Because adrenomedullin induces pulmonary vasodilation and increases myocardial inotropism, the use of this peptide could minimize the pulmonary hypertension secondary to APE and improve cardiac output. This study examined the effects of adrenomodullin in a sheep model of APE. Under ketamine/midazolam anaesthesia, variables were recorded in nonembolized sheep treated with physiological saline (Control) and in sheep with APE induced by intravenous injection of microspheres (500 mg) treated with either intravenous physiological saline (Emb) or adrenomedullin (50 ng/kg/min) (Emb+Adm) for 30 min (n = 8 per group). Plasma concentrations of cyclic adenosine (cAMP) and guanosine monophosphate (cGMP) were determined by enzyme immunoassay. Compared to values recorded 30 min after induction of APE, adrenomedullin significantly (P < 0.05) decreased pulmonary vascular resistance index by 26% and significantly increased cardiac index by 28% with no impact on mean pulmonary artery pressure. Adrenomedullin significantly lowered systemic mean arterial pressure and systemic vascular resistance index by 24% and 40%, respectively. While significant increases in cAMP concentrations were observed with adrenomedullin (P < 0.05), cGMP levels were unaltered. Adrenomedullin induces systemic and pulmonary vasodilation in a microsphere model of APE. However, an anti-hypertensive effect of adrenomedullin on the pulmonary circulation may be offset by increased CI. These findings suggest that intravenous adrenomedullin should be used cautiously for treating pulmonary hypertension because of a significant impact on systemic circulationA vasoconstrição pulmonar é responsável por grande parte dos distúrbios hemodinâmicos encontrados na embolia pulmonar aguda (EPA). A adrenomedulina, devido a sua ação vasodilatadora pulmonar e inotrópica positiva, poderia minimizar a hipertensão pulmonar e otimizar o índice cardíaco (IC) em indivíduos acometidos pela EPA. Objetivou-se avaliar os efeitos hemodinâmicos e respiratórios da adrenomedulina em um modelo de EPA induzida por microesferas em ovinos. Sob anestesia com cetamina/midazolam, mensuraram-se variáveis hemodinâmicas e respiratórias em ovelhas não embolizadas tratadas com solução salina fisiológica intravenosa (IV) (Controle) e em ovelhas com EPA induzida pela injeção IV de microesferas de silicone (500 mg), tratadas pela via IV com solução fisiológica (Emb) ou com adrenomedulina (50 ng/kg/min) (Emb+ADM) durante 30 min (n = 8 por grupo). As concentrações plasmáticas de monofosfato cíclico de adenosina (AMPc) e o monofosfato cíclico de guanosina (GMPc) foram determinadas por ensaio imunoenzimático. Comparado aos valores obtidos 30 min após da indução da EPA, a ADM diminuiu significativamente (P < 0,05) o índice de resistência vascular pulmonar em 26% e aumentou significativamente o IC em 28%, sem alterar a pressão média da artéria pulmonar. A adrenomedulina reduziu significativamente a pressão arterial média e o índice de resistência vascular sistêmica em 24% e 40%, respectivamente. Embora a concentração de AMPc tenha se elevado significativamente com a adrenomedulina (P < 0,05), os níveis de GMPc permaneceram inalterados. A adrenomedulina induz vasodilatação pulmonar e sistêmica na EPA induzida por microesferas em ovelhas. No entanto, o efeito anti-hipertensivo pulmonar da adrenomodulina foi prevenido pelo incremento do IC. A adrenomedulina IV deve ser empregada com cautela para o tratamento da hipertensão pulmonar secundária à EPA devido ao seu impacto sobre a circulação...Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

ACCURACY OF OSCILLOMETRIC (PETMAP™) AND DOPPLER METHODS TO INDIRECT MEASUREMENT OF BLOOD PRESSURE IN LAMBS

Neonatal physiology has peculiarities inherent to the age group. The objective of this study was to monitor the systemic arterial pressure in lambs during neonatal period. We used 20 Ile de France lambs, from birth and at 7, 14, 21, 28 and 35 days of life. The following parameters were analyzed: heart rate (HR), systolic (SBP), diastolic (DBP), and average blood pressure (ABP) by oscillometric method petMAP™, and SBP with Doppler. Invasive pressure validated indirect methods with the average 101.52 ± 12.04 mmHg. The averages with petMAP™ were as follows: HR (156.38 ± 37.46 bpm); DBP (63.80 ± 11.14 mmHg); ABP (81.58 ± 11.83 mmHg); SBP (112.48 ± 15.68 mmHg) and SBP by Dobler (90.27 ± 12.11 mmHg). There was significant difference in HR and blood pressure among the moments. Indirect methods differ between each other in 12.30 mmHg (overestimation   of 11%). Comparing with the invasive methods, both overestimated values of 4% and 16% in   PAS, respectively, for Doppler and petMAP™. The results showed that the Doppler method has established a good relationship with the invasive one being useful for gauging the SBP. The oscillometric method requires larger studies to be used in small ruminants. Keywords: Doppler; lamb; neonatal period; oscillometric; systemic blood pressure

Effects of different inspired oxygen fractions on sildenafil-induced pulmonary anti-hypertensive effects in a sheep model of acute pulmonary embolism

Aims: Sildenafil is a pulmonary anti-hypertensive agent whose action could be modified by different fractions of inspired oxygen (FiO(2)). We compared the effects of pure oxygen (FiO(2) &gt; 90%) or room air (21% FiO(2)) on the cardiopulmonary actions of sildenafil in sheep with acute pulmonary embolism (APE).Main methods: Forty anesthetized, mechanically ventilated sheep (34.9 +/- 5.4 kg), were randomly distributed into four groups (n = 4 per group): FiO(2) &gt; 90% without intervention; APE induced by microspheres with FiO(2) &gt; 90%, followed 30 min later by placebo (Emb(90)); or APE followed 30 min later by intravenous sildenafil (0.7 mg/kg over 30 min) with FiO(2) &gt; 90% (Emb + Sild(90)) or 21% FiO(2) (Emb + Sild(21)). Variables were recorded until 30 min after the end of treatment administration.Key findings: Microsphere injection increased (P &lt; 0.05) mean pulmonary artery pressure (MPAP) in all embolized groups (111-140% higher than that of baseline). Compared with values recorded 30 min after induction of APE (E-30), sildenafil induced greater decreases in MPAP in the Emb + Sil(90) group than in the Emb + Sil(21) group (23% and 14% lower than E-30, respectively). Hypotension (mean arterial pressure &lt;60 mm Hg) Hg) was precipitated by sildenafil due to systemic vasodilation in the Emb + Sil(21) group. Embolization lowered the PaO2/FiO(2) ratio and increased venous admixture, but sildenafil did not alter the oxygenation impairment induced by APE.Significance: Sildenafil induces a more consistent pulmonary anti-hypertensive effect and causes less interference with the systemic circulation with the concomitant use of pure oxygen than that with room air in the APE setting. (C) 2015 Elsevier Inc. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Adrenomedullin induces pulmonary vasodilation but does not attenuate pulmonary hypertension in a sheep model of acute pulmonary embolism

The pulmonary vasodilation induced by adrenomedullin may be beneficial in the acute pulmonary embolism (APE) setting. This study examined effects of adrenomedullin in sheep with microsphere-induced APE. Twenty four anesthetized, mechanically ventilated sheep were randomly assigned into 3 groups (n=8 per group): animals not subjected to any intervention (Sham), animals with APE induced by microspheres (500mg, intravenously) treated 30min later by intravenous physiological saline (Emb group) or intravenous adrenomedullin (50ng/kg/min) during 30min (Emb+Adm group). Plasma concentrations of cyclic adenosine (cAMP) and guanosine monophosphate (cGMP) were determined by enzyme immunoassay. Variables did not change over time in sham animals. In both embolized groups, microsphere injection significantly (P<0.05) increased pulmonary vascular resistance index (PVRI) and mean pulmonary artery pressure (MPAP) from baseline by 181% and 111-142%, respectively (% change in mean values). Adrenomedullin significantly decreased PVRI (18%-25%) and significantly increased cardiac index (22%-25%) from values recorded 30min after APE (E30), without modifying MPAP. Adrenomedullin decreased mean arterial pressure (18%-24%) and systemic vascular resistance index (32%-40%). Embolization significantly increased arterial-to-end tidal CO2 gradient, alveolar-to-arterial O2 gradient, and pulmonary shunt fraction from baseline, but these variables were unaffected by adrenomedullin. While adrenomedullin significantly increased plasma cAMP, cGMP levels were unaltered. Adrenomedullin induces systemic and pulmonary vasodilation, possibly via a cAMP mediated mechanism, without modifying the gas exchange impairment associated with APE. The pulmonary anti-hypertensive effect of adrenomedullin may be offset by increases in cardiac index.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP