Subjects with obstructive pulmonary disease tend to be chronically vasodilated

Abstract

1. In 12 unselected outpatients with chronic obstructive pulmonary disease and six controls, arterial pH, PaO2, PaCO2 and oxygen saturation (SaO2), forced expiratory volume in 1.0 s (FEV1.0) and vital capacity were measured. Subjects were grouped into those with or without obstruction based on the Tiffenau index. The Baseline Dyspnoea Index was employed to objectify the severity of dyspnoea and the Borg index to evaluate the subjective sensation. Blood pressure was measured with a sphygmomanometer; calf arterial flow both at rest and during reactive hyperaemia with a plethysmograph. Basal and minimal resistance were calculated.2.FEV1.0 was 26% lower in patients with obstruction than in controls, and was also lower in patients with moderate-to-severe obstruction compared with those with mild or no obstruction. Arterial flow (75% greater in the patients with obstruction) progressively increased with increasing severity of obstruction, being 54% higher in those with mild obstruction than in those with no obstruction (P<0.001), and 28% higher in moderate-severe than in mild obstruction (P<0.005). In multiple regressions, F correlated inversely with FEV1.0, PaO2 and SaO2, and directly with PaCO2. Basal resistance correlated positively with FEV1.0, SaO2 and the Tiffenau index, and inversely with PaCO2 (r=-0.52, P=0.02). Minimal resistance was significantly lower in obstructed than in non-obstructed subjects. Both basal and minimal resistance progressively decreased, although insignificantly, with worsening bronchial obstruction. PaCO2 did not correlate with any haemodynamic parameter. Borg index correlated indirectly with FEV1.0 and basal resistance directly with arterial flow.3. Patients with chronic obstructive pulmonary disease therefore tend to show chronic vasodilatation depending on hypoxia rather than PaCO2. Other mechanisms could be involved in this phenomenon. The Borg index is a good indicator of oxygen desaturation and vasodilatation.

Cytochrome P-450 epoxygenase products contribute to attenuated vasoconstriction after chronic hypoxia

“…Altered responsiveness to vasoconstrictor stimuli persists on restoration of normoxic conditions (7), which demonstrates that the consequences of long-term exposure to hypoxia are distinct from vasodilation resulting from acute exposure to this stimulus (19). In addition, prolonged arterial hypoxemia in humans is associated with persistent vasodilation of the forearm circulation and blunted constriction in response to lower body negative pressure (4,22), which indicates that obstructive pulmonary diseases may also result in attenuated vasoconstriction. Our laboratory has recently shown (8,9) that attenuated agonistinduced and myogenic vasoconstriction following prolonged hypoxic exposure is associated with persistent endothelium-dependent vascular smooth muscle (VSM) cell hyperpolarization and decreased intracellular Ca 2ϩ concentration ([Ca 2ϩ ] i ).…”

Slower rise of exhaled breath temperature in chronic obstructive pulmonary disease

“…Clinical features that are typical of COPD, such as hypoxia, hypercapnia and pulmonary hypertension, may also influence peripheral haemodynamics. However, although some studies have investigated systemic blood flow in COPD patients [4], the airway circulation and its affect on heat transfer across the bronchial wall has not yet been elucidated.…”

Hypnotic Hallucination of Body Heating Modifies Splanchnic Circulation: Haemodynamic and Ultrasonographic Pilot Study in Normal Volunteers

“…Splanchnic vasodilation was proven by a statistically significant and biologically relevant increase in superior mesenteric artery flow. According to our previous results (Casiglia et al, 2006), peripheral flow also increased, demonstrating that the mesenteric flow rise must be viewed in the frame of systemic vasodilation rather than of blood diversion from body periphery to the abdomen (Casiglia et al, 1998a(Casiglia et al, , 1998b. The paradigm of hypnotic body heating therefore reminds that of hyperthyroidism, where vasodilation occurring both in splanchnic and systemic districts is characterized by an increase of circulating blood mass and of flow velocity secondary to opening of arterial-venous shunts (Fazio, Palmieri, Lombardi & Biondi, 2004;Perko, Perko, Just, Secher, & Schroeder, 1996).…”