These results are consistent with those of Daoud et al; however, two comments on Pv02, which was not measured in the previously cited study, should be made: (1) since a fall in Pv02 appears to contribute significantly to the HPV response magnitude, the hyperkinetic heart syndrome restoring normal Pv02 may have played a role in the impairment of the HPV mechanism even in the presence of hypoxemia; and (2) although many factors led to a raised cardiac output, the rise was exactly adjusted to maintain a normal Pv02. naturalbreastenhancementpill.com
In two patients, almitrine bismesylate was infused at a dose of 0.25 mg/kg/h. This drug is known to increase pulmonary arterial pressure and PVR- and to decrease Va/Q mismatching in obstructive pulmonary disease. This was designed to find out if the hemodynamic abnormalities and the impaired gas exchange were due to an alteration in the pulmonary circulation. Breathing a hypoxic mixture could have been dangerous in these patients. After 15 minutes of infusion, hemodynamic variables and gas exchange parameters had not changed from baseline values, although the plasma levels of almitrine bismesylate were within potent values (73 mg/ml and 81 mg/ml, respectively). This suggested that the dilated pulmonary anastomoses aiid the vessels of the ventilated pulmonary areas were unable to react to a vasoconstrictive stimulus. The absence of improvement in gas exchange was consistent with the mechanism of action of this drug because the perfused and ventilated units of the present patients lungs were fairly homogeneous (log SD = 0.47 and 0.45, respectively, which is close to the normal value).
In conclusion, although severe breathlessness and hypoxemia are unusual in patients suffering from cirrhosis of the liver in the absence of cardiorespiratory disease, the gas exchange abnormalities are primarily related to an alteration in the pulmonary circulation. This was indicated by the fall in the PVR and the increased true shunt. The normal regulating mechanisms of the microcirculation and of pulmonary vascular tone may thus be impaired in cirrhosis of the liver, possibly via an alteration of humoral mediation.
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