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Pulmonary artery catherization
valsalva maneuver
squeezes blood out of pumonary circulation reduces vascular diameter, increases PVR
left ventricular failure:
blood dams up in pulmonary vessels, distending them and reducing PVR
bronchial systemic venous blood drains directly into thw what?
pulmonary veigns
bronchial blood flow is only what of the cardiac output? which means that the anatomical shunt from this source is usually less than what?
1 to 2 %... it's less than 2%
the lower resistance in the pulmonary circulation is implied by the fact that it's pressures are what even though it receives the same cardiac output ast the systemic circulation
the resistance to blood flow in the pulmonary circulation is approximately what as it is in the systemic circulation
one tenth
pulmonary venous pressure is nearly equal to left atrial pressure, which is essentially equal to what
left ventricular end-diastolic pressure
the pressure inside the filled ventricle just before it contracts. this so-called filling pressure is also known as the what?
left ventricle's preload
the what accurately reflects changes in left atrial pressure because the stationary fluid column inside the catheter is functionally extended from the catherter's tip to the left atrium? for this reason, the what is commonly used as a clinical indidcator of left ventricular funtion
blood drawn from the proximal channel is a mixture of what blood?
superior and inferior vena cava venous
A thoroughly mixed venous blood sample reflecting the true average of the body's venous oxygen content must be obtained from the what, through the catherter's what channel
pulmonary artery and the distal channel
the amount of blood the heart pumps each minute can be clinically measured with a pulmonary artery catheter via what technique?
a pulmonary vascular resistance (PVR) of 1.2 mm Hg (l/min) is equivalent to what
a pressure gradient of 18.2 mm Hg is needed to drive 1 L/min of blood through the systemic circulation )(compared with 1.2 mm Hg in the pulmonary circulation). this pressure converts to approximately what
in a rising left atrial pressure due to inadequate left ventricular pumping action the elevated what is reflected back throughout the pulmonary veins, capillaries, and arteries, dilationg them and doing what to there vascular resistance?
LAP it decrases their vascular resistance
naturally occurring humoral substances in the body produce vasodilattion by stimulating the production of this so-called endothelium-derived relaxing factor (EDRF) endogenous substances include what?
acetylcholine, bradykinin, histamine, thrombin, serotonin, atp (adenosine triphosphate) and some prostaglandins.
nitric oxide inhalation has been especially beneficial in treating who? with persistent pulmonary hypertension of who
infants and the newborns
the most important chemical factor causing pulmonary vasoconstriction is what
low alveolar oxygen pressure or alveolar hypoxia
A PA02 of less than 70 mm Hg usually elicits this effect, known as what
hypoxic pulmonary vasoconstriction
high Pa02 (hyperoxia) has what effect on normal pulmonary circulation, probably because pulmonary vessels in normal lungs have what muscle ton and their vasodilating ability is what?
little, little, and minimal
in people who have hypoxia, improved oxygenation significantly does what?
dilates pulmonary vessels and dramatically decreases pvr
at a normal PaO2 arterial pHmust decrease below what to cause a significant increase in what?
7.25 and PVR
hpv is inhibited by various mediators present in the blood that cause vasodilation, such as the endothelial-derivved substances what and what?
nitric oxide and prostacyclin
hpv is also inhibited by drugs that block what? or stimulate what
aspha-adrenergic, beta-adrenergic receptors
hpv is inhibited by what 3 things?
increased left atrial pressure high alveolar pressure and high blood PH
the hpv response is often diminished in patients surfering from acute lung injuries such as?
burn and smoke inhalation, sepsis, and acute respiratory distress syndrome
some of these alternative vasodilators, which are inhaled as aerosols, includingg what?
prostacyclin (PGI2) sildenafil (viagra), nitroprusside, and nitroglycerin
in zone I, alveoli are ventilated but have no blood flow, which constitutes alveolar what?
arterial pr3essures always exceeds what pressures? even in the uppermost apical lung regions, and zone I
alveolar, does not exist
certain respiratory maneuvers such as what can momentarily raise alveolar pressures above arterial pressure creating what zone conditions in gravity-independent lung regions
exhaling against a closed glottis, blowing a trumpet or coughing
the only force tending to move fluid into the capillary is the blood's what pressure of approx what mm Hg
oncotic and 28mm Hg
pulmonary edema is the accumulation of fluid in the interstitial spaces between capillaries and alveoli. causes of pulmonary edema include what 4 things?
1. increased hydrostatic pressure
2. increased capillary permeability
3. decreased plasma oncotic pressure
4.insufficient lymphatic drainage
a common cause of hydrostatic pulmonary edema is what?
Left ventricular failure.
coronary artery disease may reduce blood flow to the what ventricular muscle, reducing the effectiveness of its pumping action
over administration of intravenous (IV) fluids may create what with similar results.
hypervolemia or fluid overload
this type of edema is associated with a high pcwp, and is called what?
cardiogenic pulmonary edema
acute lung injuries that damage the alveolar capillary membrane may increase the membrane's what to fluids and cause pulmonary edema
this kind of edema is often called what two types of pulmonary edema
highpermeability and noncardiac
causes of alveolar capillary membrane injury include severe infections such as what?
pneumonia, endotoxins of sepsis, oxygen toxicity, ARDS and inhaled noxious substances
the rario of alveolar CO2 excretion to blood oxygen uptake is called the what and it's value is normally approximatel
respiratory exchange ratio..... 0.8 (r=vco2/vo2=200/250=0.8
a normal PAO2 for a person breathing room air at sea level, with a PaCO2 equal to 40 mm Hg and an R equal to 0.8 is approx what mm Hg this is shown as follows
PAO2=0.2093 (760-47) - ((40 x 1.25
100 mm Hg
the rate of gas diffusion in the lung is iversely proportional to its molecular weight and directly proportional to what?
its molecular weight and directly proportional to its solubility
because oxygen is a lighter molecule, it diffuses through a what 1.17 times faster than CO2
gas medium
carbon dioxide is approx. how much more soluble than oxygen?
alveolar capillary membrane defects limits what diffusion long before they limit CO2 diffusion?
exercise immediately exposes the diffusion abnormality problem because it shortens the blood's transit time through the capillary, preventing oxygen equilibrium. thus patients with thickened alveolar capillary membranes are most likely to show what?
evidence of oxygen diffusion impairment during exercise
oxygen diffusion rate through the alveolar capillary membrane is normally what?
perfusion limited
If oxygen equilibrium between the alveolus and capillary never occurs because of thickened membranes, oxygen transfer is then truly what?
In such an instance it is the alveolar capillary membrane, not what that influences the oxygen transfer rate
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