Effect of saline infusion for the maintenance of blood volume on pulmonary gas exchange during temporary abdominal aortic occlusion

We analyzed the effects of saline infusion for the maintenance of blood volume on pulmonary gas exchange in ischemia-reperfusion syndrome during temporary abdominal aortic occlusion in dogs. We studied 20 adult mongrel dogs weighing 12 to 23 kg divided into two groups: ischemia-reperfusion group (IRG, N = 10) and IRG submitted to saline infusion for the maintenance of mean pulmonary arterial wedge pressure between 10 and 20 mmHg (IRG-SS, N = 10). All animals were anesthetized and maintained on spontaneous ventilation. After obtaining baseline measurements, occlusion of the supraceliac aorta was performed by the inflation of a Fogarty catheter. After 60 min of ischemia, the balloon was deflated and the animals were observed for another 60 min of reperfusion. The measurements were made at 10 and 45 min of ischemia, and 5, 30, and 60 min of reperfusion. Pulmonary gas exchange was impaired in the IRG-SS group as demonstrated by the increase of the alveolar-arterial oxygen difference (21 ± 14 in IRG-SS vs 11 ± 8 in IRG after 60 min of reperfusion, P = 0.004 in IRG-SS in relation to baseline values) and the decrease of oxygen partial pressure in arterial blood (58 ± 15 in IRG-SS vs 76 ± 15 in IRG after 60 min of reperfusion, P = 0.001 in IRG-SS in relation to baseline values), which was correlated with the highest degree of pulmonary edema in morphometric analysis (0.16 ± 0.06 in IRG-SS vs 0.09 ± 0.04 in IRG, P = 0.03 between groups). There was also a smaller ventilatory compensation of metabolic acidosis after the reperfusion. We conclude that infusion of normal saline worsened the gas exchange induced by pulmonary reperfusion injury in this experimental model.

Effects of almitrine on the ventilatory control, breathing pattern and maximal exercise tolerance in hypoxemic patients with chronic obstructive pulmonary disease

Almitrine bismesylate improves arterial blood gases in patients with chronic obstructive pulmonary disease (COPD), but side effects such as increase of ventilatory drive and dyspnea have been reported in some studies. We studied 18 COPD patients (mean age=59.1 years; mean FEV1=0.921; mean PaO2=58.6mmHg) in a double-blind randomized study using placebo or almitrine 50 mh twice a day by mouth, for 60 days. In contrast to the placebo group, 40 per cent of the patients in the almitrine group presented a significant increase in PaO2 and a decrease in P(A-a))2>=5mmHg during submaximal exercise after 60 days of treatment. Ventilatory drive and the breathing pattern were measured at rest and during submaximal exercise. Both goups showed high levels of ventilatory drive and atachypneic breathing pattern before drug tratment and no modification was found 30 and 60 days after treatment. Metabolis, cardiovascular and ventilatory variables were studied during an incremental to maximum exercise symptom-limited test (cycloergometry). Maximal VO2 ranged from 46 to 52 per cent and heart rate from 76 to 78 per cent in relation to the predicted values. The percent ratio of ventilation at maximal exercise to maximal voluntary ventilation at rest ranged from 86 to 94 per cent. These results show that the reduction of ventilatory capacity was the main factor decreasing the aerobic performance of our COPD patients. Maximal exercise tolerance (VO2 max) did not change after almitrine treatment. Negative factors like an increase in neuromuscular drive did not occur, and positive factors like an increase in PaO2 and oxygen transport had no critical influence on exercise performance in our ventilatory-limited COPD patients.

Correlation between arterial oxygen and carbon dioxide levels and response to almitrine bismesylate in normal dogs

The objectives of this study were: 1) to test the action of small doses of almitrine bismesylate (0.004 mg/Kg body weight/min) on the arterial blood gases and on pulmonary and systemic circulation during hypoventilation under controlled mechanical ventilation; and 2) to investigate possible correlations between arterial blood. O2 and CO3 levels and the response to the drug. Twenty one dogs divided into two groups were studied under controlled ventilation in a double-blind fashion: hypoventilation + placebo (HP) (seven dogs); hypoventilation + almitrine (HA) (fourteen dogs). The results showed no significant variations of the gas ex-change and hemodynamic varibles in the HP group. In the HP group, during almitrine bismesylate infusion, despite the lack of variation in the pulmonary ventilation, the PaO2 increased from 46.1 torr to 51.7 torr, the PaCO2 decreased from 61.9 torr to 57.7 torr. There were no significant variations of hemodynamic variables in the HA group. Thus we conclude that the drug improved arterial blood gases (PaO2 increased) with small increase in alveolar ventilation (PaCO2 decreased) despite the lack of changes in pulmonary ventilation, and that the drug has action on the arterial PO2 potentiated by hypoxemia and hypercapnia

Gas exchange during differential mechanical ventilation after unilateral lung injury induced by hydrochloric acid: experimental study in dogs

In order to test gas exchange in lungs with unilateral injury, when mechanical ventilation is needed, three groups (G-I, G-II, G-III) of seven dogs each were studied. Injury was induced in the left lung by injecting 0,lN, 1.0 ml per kg of body weight of hydrochloric acid, pH = 2.00. For groups I and II a conventional volumetric artificial ventilator was used. G-I was the control group. In group II a bilateral positive end-expiratory pressure (PEEP) was introduced during the last phase (phase 3) of the experiment, and in group III, a prototype of a volume cycled ventilator, with separated bellows, was used delivering tidal volumes separately to each lung through a Carlens' tube. In G-III, PEEP was introduced only to the injured lung in the last phase of the experiment. Phase l (Fl), basal phase, was similar in the three groups; phase 2 (F2) was the period after instillation of hydrochloric acid and phase 3 was the period after a 5 cmH2O bilateral PEEP was used in G-II, and a selective PEEP to the left lung was used in G-III. In each phase of the experiment, hemodynamic and gas exchange variables were obtained. Our results allowed the following conclusions: the differential lung ventilation technique maintained the alveolar ventilation of the dogs and the differential lung ventilation with unilateral PEEP was better for gas exchange (phase 3) than the conventional ventilation with bilateral PEEP (CPPB).

Ventilacao mecanica. / Mechanical ventilation

Um tema ainda sob discussao na literatura mundial e a ventilacao de alta frequencia.A ausencia de relatos sobre este tema em nossa literatura nos estimulou a revisar a ventilacao mecanica habitual, hoje denominada tradicional, e a ventilacao de alta frequencia. Abordamos o desenvolvimento historico do suporte mecanico da ventilacao tradicional e de alta frequencia, a terminologia empregada em relacao as diversas tecnicas utilizadas, com sua repercussoes pulmonares e hemodinamicas

Cintigrafia de ventilacao pulmonar por aerossol em diversas patologias pulmonares. / Lung inhalation scintigraphy with radioactive aerosols in several pulmonary diseases

Salienta-se a importancia da cintigrafia de ventilacao pulmonar com acido dietileno-tetramino-pentacetico ligado ao tecnecio 99m atraves de um sistema produtor de aerossol, ao lado da classica cintigrafia de perfusao com macroagregado de albumina marcado com tecnecio 99m, como meio diagnostico em diversas patologias pulmonares.Sao apresentados os aspectos da cintigrafia de ventilacao-perfusao em 15 individuos sem doenca pulmonar, fumantes e nao-fumantes. As caracteristicas destas cintigrafias sao tambem discutidas em 34 pacientes com diversas patologias pulmonares cancer de pulmao, doenca pulmonar obstrutiva cronica. Conclui-se que devido a qualidade das imagens obtidas, facil procedimento, inocuidade, baixo custo, alem de acrescentar informacoes aos metodos convencionais, a associacao das cintigrafias pulmonares de ventilacao e de perfurasao representa meio diagnostico de valia em diversas patologias pulmonares

E a pressão de capilar pulmonar expressão de átrio esquerdo na vigência de respiração mecânica com pressão positiva expiratória? / Is pulmonary capillary wedge pressure expression of left atrium pressure during mechanical respiration with positive pressure ventilation?

As pressoes do atrio esquerdo e do capilar pulmonar foram medidas concomitantemente em 4 caes submetidos a respiracao mecanica com pressao positiva (PPE).Foram estudadas as relacoes entre estes valores (pressao de atrio esquerdo e pressao de capilar pulmonar, nivel de PPE e pressao de capilar pulmonar; nivel de PPE e pressao de atrio esquerdo), obtendo-se correlacoes positivas significativas; rs = 0,91; rs = 0,62 e rs = 0,74, respectivamente. Conclui-se que os valores da pressao de capilar pulmonar refletem fielmente os valores da pressao do atrio esquerdo, mesmo na vigencia de respiracao mecanica com pressao positiva expiratoria ate 15 cmH1O

Tratamento da asma bronquica, no periodo intercrises, em adultos. / Treatment of bronchial asthma, during intercrisis in adults

Num estudo multicentrico abrangendo 14 Servicos de Pneumologia e Alergia, 142 pacientes portadores de asma extrinseca receberam, durante quatro meses, l mg de cetotifeno a cada 12 horas, por via oral.Neste periodo foi observada uma diminuicao estatisticamente significante na frequencia dos episodios de falta de ar, bem como a sua duracao e intensidade. Observou-se tambem uma diminuicao no uso de medicacao sintomatica concomitante, particularmente dos broncodilatadores e corticosteroides.Vinte e um por cento dos pacientes apresentaram efeitos colaterais, na maioria das vezes de pequena intensidade, a mais frequente queixa tendo sido sonolencia. No computo geral, 73% dos pacientes se beneficiaram com o uso do cetotifeno no tratamento profilatico da asma bronquica, sendo que em 50% dos pacientes os sintomas desapareceram ou se tornaram minimos

Estudo da associacao trimetropim/sulfametoxipirazina no tatamento das pneumonias. / Study of trimethoprim/sulfamethoxypyrazine association in the treatment of pneumonia.

Os autores estudaram 24 pacientes com pneumonia, usando uma associacao Trimetroprim 250mg/Sulfametoxipirazina 200mg(+) na posologia de 2 capsulas no 1o. dia e 1 capsula ao dia por 9 dias, completando dez dias de tratamento. Obtiveram bons e otimos resultados em 91,7% dos pacientes tratados,notando-se apenas um paciente com problemas passageiros de tolerabilidade, que nao impediram que terminasse o tratamento. Concluem que esta associacao e uma opcao valida para o tratamento de infeccoes respiratorias.}