Pulmonary arterial hypertension – clinical profile and diagnosis
Simon Stewart in A Clinician's Guide to Pulmonary Arterial Hypertension, 2008
Clinical profile It is important to remember that the key underlying haemodynamic factor in any form of PH is the increase in the pulmonary vascular resistance in response to the remodelled pulmonary circulation. The primary driver of this pathological process, therefore, is largely clinically silent until the response is manifested by changes (both acute and chronic) in right ventricular function. As such, without treatment, to relieve chronic PAH, particularly in its severest form, patients typically develop progressive right ventricular hypertrophy, dilatation, and associated right ventricular dysfunction – see Figure 4.1.62-65 Without appropriate treatment, therefore, the right ventricle progressively fails, eventually resulting in death. As indicated, many of the pathological changes associated with PAH may not produce significant and readily indentifiable symptoms until the disease has progressed significantly (i.e. when right heart failure has developed as a consequence of increased pulmonary vascular resistance). In addition, the clinical profile of PAH may also be obscured by the underlying disease state (e.g. systemic sclerosis), particularly where other factors have a detrimental effect on exercise tolerance.
Critical care and emergency surgery
Stephen Brennan in FRCS General Surgery Viva Topics and Revision Notes, 2017
Diagnostic laparoscopy is safe and effective when used in pregnancy. Several studies have shown that pregnant patients may undergo laparoscopic surgery safely during any trimester without any appreciated increased risk to the mother or foetus. Systemic inflammatory response syndrome differs from sepsis in that sepsis is SIRS with a documented infection. Septic shock is sepsis with refractory arterial hypotension and/or need for inotropes despite adequate fluid resuscitation. The physiological changes occurring in patients with severe sepsis and septic shock are myriad and include changes that are clearly detrimental such as decreased contractility of the left and right ventricle, increased venous capacitance, increased pulmonary vascular resistance, and capillary leak. A damage control laparotomy (DCL) is a laparotomy performed usually for trauma where the primary aim is to control haemorrhage and limit sepsis in the first instance. The central nervous system degeneration, trauma, or neoplasms may affect the hypothalamic regulatory centre.
Physiology and Pollutant Damage to Vascular Perfusion: Changes in the Sympathetic Nervous System Function
William J. Rea, Kalpana Patel in Reversibility of Chronic Disease and Hypersensitivity, Volume 3, 2015
Pollutant damage to the physiology of the peripheral vessels and heart is widespread and must be dealt with in order to ensure good myocardial and vascular function. Vascular perfusion generated from the heart pump and peripheral resistance is the most important physiological function of the vascular tree. Perfusion is signicant because it delivers oxygen and other nutrients both directly and indirectly to all cells and because it removes waste. Oxygen is essential for both the normal electrical activity and pumping efciency. The amount of oxygen that vascular perfusion delivers to an area determines both tissue function and dysfunction. As long as there is a balance between pumping and vascular resistance, good homeostasis occurs with no arrhythmias or heart failure. Chemical sensitivity does not exacerbate the imbalance initially, but as the chemical sensitivity progresses, the heart and peripheral vascular involvement increases the sensitivity.
Hemodynamic Changes of Adenosine Diphosphate, Adenosine Triphosphate, and Thrombin in Relation to Their Platelet-Aggregating Activity
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 1971
J. Swedenborg, G. Taylor, P. Olsson
ADP and ATP were infused into the systemic and pulmonary circulation of dogs. Thrombin was infused into the pulmonary circulation. All the agents caused a decreased platelet count. ADP and ATP caused an increase in cardiac output. Pulmonary vascular resistance as well as total peripheral vascular resistance were decreased. Thrombin caused an increase in pulmonary vascular resistance and a decrease in total peripheral vascular resistance.
Vascular Pressure-Flow Analysis in Normal and Hypoxemic Spontaneously Hypertensive Rats
Published in Clinical and Experimental Hypertension. Part A: Theory and Practice, 1982
Gerald M. Walsh, Alfonso J. Tobia
The pressure-flowurelationship of the autoperfused subclavian vascular bed was compared in Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) after spinal cord transection. Studies were performed under normoxemic and hypoxemic conditions. In adult SHR, vascular resistance was greater relative to WKY under both conditions. In young (8 week old) SHR vascular resistance was consistently greater over a wide range of perfusion pressures compared to young WKY rats when blood oxygen content was normal. Vascular resistance was not different between young SHR and WKY when the animals were hypoxemic. The results demonstrated that elevated vascular resistance in adult SHR was independent of oxygen availability and supraspinal nerve function; however, in young SHR elevated vascular resistance was dependent upon oxygen availability, although independent of supraspinal nerve function.
Response to Nitric Oxide during Adult Cardiac Surgery
Published in Journal of Investigative Surgery, 2002
Alann R. Solina, Steven H. Ginsberg, Denes Papp, Enrique J. Pantin, John Denny, Ilankeeran Ghandivel, Tyrone J. Krause
Pulmonary hypertension is associated with significant morbidity and mortality in adult cardiac surgery patients. Inhaled nitric oxide is known to be a selective pulmonary vasodilator in this setting. However, it is not known which cardiac surgery patients benefit most from nitric oxide therapy. This study sought to prospectively determine whether a patient's baseline pulmonary vascular resistance could be used to predict responsiveness to inhaled nitric oxide therapy. Subjects were 30 consecutive cardiac surgery patients with pulmonary hypertension immediately prior to induction of anesthesia. There were 2 study groups: Group 1 ( n = 15) had an initial pulmonary vascular resistance between 125 and 300 dyn-s/cm 5 , while group 2 ( n = 15) had an initial pulmonary vascular resistance of greater than 300 dyn-s/cm 5 . Both groups were empirically treated with inhaled nitric oxide (30 ppm) upon separation from bypass. The conduct of anesthesia, surgery, and cardiopulmonary bypass were controlled. A therapeutic algorithm dictated the use of vasoactive substances for all patients. Heart rate, mean arterial pressure, pulmonary vascular resistance, peripheral vascular resistance, cardiac index, and right ventricular ejection fraction were monitored throughout the operative experience. Patients with a higher initial pulmonary vascular resistance had a significantly greater percent reduction in pulmonary vascular resistance after the initiation of nitric oxide therapy. This study suggests that pulmonary vascular resistance is more dramatically affected by inhaled nitric oxide in cardiac surgery patients with a greater degree of pulmonary hypertension.
Related Knowledge Centers
- Cardiac Output
- Blood
- Circulatory System
- Vasodilation
- Vasoconstriction
- Total Peripheral Resistance