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Biomedical subjects

J Sandoval

Publications and source records attributed to J Sandoval.

At least 73 records · Page 4Linked to original sources
PubMed1980

Behavior of the pulmonary circulation in the grossly obese patient. Pathogenesis of pulmonary arterial hypertension at an altitude of 2,240 meters.

Twenty persons living at an altitude of 2,240 meters were studied in order to examine the relative roles of passive and active factors in the genesis of pulmonary arterial hypertension in obesity (overweight, 75 +/- 39 percent). Pulmonary arterial hypertension was present in 80 percent (16) of the patients (mean pulmonary arterial systolic pressure, 45 +/- 17 mm Hg). In 95 percent (19) of the 20 patients, resistance to pulmonary flow at the end of diastole was increased (estimated mean pulmonary arteriolar resistance, 210 +/- 144 dynes.sec.cm-5; mean pulmonary arterial diastolic-pulmonary wedge pressure gradient 7.86 +/- 1.40 mm Hg). The mean arterial oxygen pressure was 50 +/- 9 mm Hg, the arterial carbon dioxide tension was 37 +/- 6 mm Hg and the arterial pH was 7.42 +/- 0.08. Since the pulmonary arterial systolic pressure has been reasonably predicted (r = 0.91; P < 0.001), it would appear that the compliance of the elastic pulmonary arteries in obese patients follows a normal pattern. The behavior of the right ventricular end-diastolic pressure at rest (mean change, 4.6 mm Hg; P < 0.001) and of the pulmonary wedge pressure (mean change, 4.7 mm Hg; P < 0.001) during passive lifting of the legs was indirect evidence of the increase in pulmonary blood volume. The presence of an abnormal resistance to pulmonary blood flow at the end of diastole is suggestive of a decrease in the distention of the pulmonary microcirculation. The pulmonary arterial diastolic-pulmonary wedge pressure gradient and the pulmonary arterial diastolic pressure were related to arterial oxygen unsaturation (r = 0.70; P < 0.05) but not to the concentration of hydrogen ions; thus hypercapnic acidemia appears as a secondary factor in the genesis of pulmonary arterial hypertension at high atitudes. The explanation could be the relative hyperventilation of high altitudes, with a compensatory metabolic alkalosis. The increased pulmonary blood volume and the alveolar hypoxia are the main causes in the pathogenesis of pulmonary arterial hypertension in the grossly obese patient at this altitude.

Altitude↗
PubMed1976

Current medical practice and hyperactive children.

An extensive questionnaire was completed by 48 physicians, detailing the medical and behavioral information they collect in forming a diagnosis of conditions that have hyperactive behavior as a symptom. Results indicate that diagnoses are made primarily on the basis of behavioral indicators, and indicators and information from the child's personal medical history, rather than from other data collected during the physical exam.

Attitude of Health Personnel↗
PubMed1976

Hyperactive children and the efficacy of psychoactive drugs as a treatment intervention.

Characteristics of hyperactive children, including speculation in regard to etiology, are reviewed. Drug effects studies and drug treatment of hyperactive behavior are examined, and unresolved issues are discussed. Conclusions indicate that individual differences in hyperative children should form the basis for treatment planning, rather than simply treating groups of children under the rubric "hyperactivity."

Amphetamines↗
PubMedDate not supplied

[Pulmonary thromboendarterectomy as a treatment of chronic pulmonary arterial hypertension secondary to unresolved pulmonary thromboembolism. A preliminary report].

This is a preliminary report of our initial experience with thromboendarterectomy in the treatment of four patients with chronic major-vessel thromboembolic pulmonary hypertension. Before surgery, these patients all had severe pulmonary hypertension and cor pulmonale as well as significant abnormalities in lung function (mechanics and gas exchange). They were in class III-IV (NYHA). One of our patients died immediately after the procedure as a result of major bleeding. The remaining three surviving patients have shown a remarkable improvement in both, pulmonary hemodynamics and lung function which has been translated in an also significant improvement in their clinical condition. Although there is still a significant risk involved with this procedure, the thromboendarterectomy represents a reasonable and useful therapeutic approach for selected patients with this deadly form of chronic pulmonary hypertension in which other forms of treatment have proved to be unsuccessful.

Adult↗
PubMedDate not supplied

[The effect of gelfoam embolism in vascular conduction and critical pressure in the isolated canine lobe].

Pulmonary pressure-flow curves, hemodynamic and blood gas parameters in West's zone II condition were obtained in nine isolated in situ left lower lobes (LLL) before (condition A), and after 15, 30 and 60 minutes of lobar gelfoam embolization (GE) (condition B) in order to know the natural history of this model. After GE a decrease in PaO2 and lobar O2 were noticed (p less than 0.05). Vascular conductance (p less than 0.001) and lobar blood flow decreased (p less than 0.05), accompanied by a significant increase in the inflow (p less than 0.01) and in the mean closing pressures (p less than 0.01). These parameters did not change during the time of observation at condition B. Nor the cardiac output or the minimal closing pressure changed in relation to condition A. LLL angiographic findings showed evidence of arterial occlusion and the pattern of obstruction was not homogeneous. Lobes histology showed occluded arteries of more than 300 micrometers of diameter. We concluded that in this canine model of increased pulmonary vascular resistance, pulmonary vascular conductance and mean closing pressure change, remain stable during 60 minutes after GE allowing us to know the natural history of the preparation. Condition than allow to perform and evaluate other interventions on lung vascular mechanics in the experimental setting of pulmonary embolization.

Animals↗
PubMedDate not supplied

[Effect of dopamine on lung vascular mechanics. Its study in the isolated canine lobe model embolized with gel foam].

After inducing an increase in pulmonary vascular resistance (Rp) in an isolated in situ lobe (LAIS) embolized with gelfoam (GE), the effect of dopamine infused at 12 mcg/kg/min in eight mongrel dogs was evaluated. We studied the rectilinear pressure-flow (QL/PL) relationship, the hemodynamic and blood gas before (condition A), 15 minutes later GE (condition B) and after dopamine infusion (condition C). After GE a decrease in QL and an increase in inflow (PL) and mean critical closing pressures (PLi) were noticed (p less than 0.01). Also decrease in pulmonary vascular conductance (1/Rp) was noted. At condition C a rise in QL and PL were noticed (p less than 0.01), but 1/Rp and PLi did not change. We concluded that dopamine in the LAIS with increased Rp at the used doses does not have vasoactive action for those vessels responsible for the phenomenons where flow resistance or mean critical closing pressure occurs.

Animals↗
PubMedDate not supplied

[Effects of venous segment pressure on the critical closure pressure, in the isolated lung lobe from dogs in situ].

In an isolated in situ canine left lower lobe preparation we studied the influence of the distal vascular compartment or venous pressure (PV) on the pressure of arterial vascular segment at zero flow or minimal critical closing pressure (MCCP), while alveolar pressure was held constant and below MCCP. The MCCP-PV curve showed an independent segment when PV was less than 8 mmHg. Above this value (that we define as PV), an slope of 1.08 was found. Our findings indicate that MCCP is not MCCP if PV greater than 8 mmHg (it is MCCP). Because MCCP is higher than alveolar pressure, MCCP must be the back pressure for flow. This finding is not in disagreement with the new concept regarding that MCCP is the back pressure for flow and not alveolar pressure in West's zone II condition.

Animals↗
PubMedDate not supplied

[Effects of the chest wall and air volume on the perivascular pressure of the arterial segment. Study of the isolated canine lobule].

Ten isolated in situ canine left lower lobes (LLL) were studied in West zone II condition. In four dogs (group I) the chest wall surrounding the LLL was surgically removed, in the remaining dogs (group II) this procedure was not done. After basal parameters were obtained, minimal critical pressure (MCCP) was recorded and the influence of increasing alveolar pressure (PA) from o to 20 mmHg was noted. For group I lobes, PA value did not influence MCCP measurements, thus an independent relation between the pressures was found (delta MCCP/delta PA = 0). For group II lobes, when PA less than 6.8 +/- 2.1 mmHg also a delta MCCP/delta PA +/- was noted. Above this PA (PA1) a slope of 0.25 +/- 0.04 was documented for the delta MCCP/delta PA relationship. On the basis of our findings we conclude that MCCP is independent form PA. However if this relationship is studied in the isolated in situ LLL, at open chest with the condition of integrity of the chest wall when PA1 is applied the changes in MCCP are the result of the effect of lung inflation on the chest wall resulting in changes of the extravascular compliance (of the arterial segment) and is not due to a direct influence of PA on MCCP.

Animals↗
PubMedDate not supplied

[Use of blood oxygen partial pressure in the right atrium in the calculation of intrapulmonary shunt].

In order to assess the usefulness of blood samples taken from the right atrium (RA) in the calculation of intrapulmonary shunt (Qs/Qt), we correlated the values of Qs/Qt obtained through RA sampling with those obtained form a simultaneous sample of blood from the pulmonary artery (PA). The study was done in six mongrel dogs (15 to 23 Kg) who were anesthetized and artificially ventilated. The Qs/Qt measurements were repeated at different levels of cardiac output (CO). Changes in CO were elicited by both mechanical (A-V fistula) and pharmacological (Hydralazine) means. Besides the Qs/Qt correlation we also correlated the oxygen-hemoglobin saturation (Sat %) and oxygen tension (PvO2) values between the two sites of mixed venous sampling. The correlations of the different parameters between RA and PA samples we obtained were as follows: Qs/Qt r = 0.93 (p less than 0.001); Sat % r = 0.87 (p less than 0.001); and for PvO2 r = 0.91 (p less than 0.001). The significant correlations of these parameters were maintained independent of the CO level. We conclude that in our model a sample of blood obtained from the RA is useful for the calculation of Qs/Qt.

Animals↗