Midterm 2 Flashcards
A pt. w/ Kussmaul’s respirations most likely has?
Metabolic Acidosis
Which organ system maintains the normal lvl of HCO3- at 24mEq/L?
Renal System
An ABG result shows the pH to be 7.56 and the HCO3- to be 23 mEq/L. Which of the following is the most likely disorder?
Respiratory Alkalosis
When is the rate of gaseous diffusion across a biological membrane decreased?
The partial pressure gradient is low
What is the average thickness of the Type I alveolar cell?
0.1-0.5 microns
Based on the following ABG results, what is the most likely acid-base diagnosis?
pH 7.38, PCO2 21mmHg, HCO3- 11.7 mEq/L
Fully compensated metabolic acidosis
The affinity of Hb for carbon monxide (CO) is approximately how many times greater than its affinity for oxygen?
200 or greater
In order to assess the events occurring at the tissue level, especially tissue oxygenation, what parameter would you sample and measure?
Mixed venous blood
According to the Bohr effect, when the pH drops, what happens?
- The affinity of Hb for oxygen decreases
- The Hb saturation for a given PO2 falls
- The Hb saturation fo a given PO2 rises
1 &2
What is the term for the uppermost portion of the uprght lung?
Apex
What type of epithelium extends from the trachea to the respiratory bronchioles
pseudostratified ciliates columnar
According to the Henderson-Hasselbalch equation, the pH will be normal as long as the ratio of HCO3- to dissolved CO2 is which of the following?
20:1
In which of the condition will erythrocyte concentration of 2,-DPG be decreased
Banked blood
Causes of respiratory acidosis in pts with normal lungs include which of the following?
- neuromuscular disorders
- Spinal cord trauma
- Anesthesia
- Central nervous system
1,2,3 and 4
When does a state of alkalemia exist?
- The HCO3-/CO2 ratio exceeds 20:1
- The blood pH exceeds 7.45
- The blood PCO2 exceeds 54 mmHg
1 and 2
An area of the lungs has no ventilation but is normally perfused by the pulmonary circulation. Which of the following statements are correct?
- Blood exiting the pulmonary capillary will have a PO2 = 40 and a PCO2 = 46
- The area represents an alveolar shunt.
- The V/Q is 0
1,2, and 3
An ABG result shows pH of 7.35 of 30mmHg, and HCO3- of 18 mEq/L. What compensatory measure has the body taken to at least partially compensate for the acid-base disorder?
Blown off CO2
Compensation for respiratory alkalosis occurs through what?
Renal excretion of HCO3-
Carbon dioxide diffuses across the alveolar-capillary membrane about how many times faster than oxygen?
20
An increase in the H+ ion concenration of the [H+] of the blood due only to an increase in the arterial PCO2 (hypercapnia) best describes which?
Respiratory acidosis
As the amount of oxygen that dissolves in the plasma increases, what is it directly proportional to?
Its partial pressure
What is the primary chemical event in metabolic alkalosis?
Increase in blood HCO3- levels
What is the most common cause of respiratory alkalosis?
Hypoxemia
Primary metabolic alkalosis is associated with which of the following?
Gain of buffer base
What are the primary components of the upper airway?
Nose, oral cavity, and pharynx
What compensates for a metabolic alkalosis?
Hypoventilation
A decrease in the H+ ion concentration [H+] of the blood caused by a low PaCO2 best describes which of the following?
Respiratory alkalosis
What is the approximate normal level of CO2 production for an adult?
200ml/min
What affect does hyperventilation have on HCO3- recover in the kidneys?
Less H+ excretion, greater HCO3- loss
An area of the lung has no blood flow but is normally ventilated. Which of the following statements are true about this area?
- The alveolar gas is like air (PO2 = 150; PCO2 = 0)
- The area represents alveolar dead space
- The V/Q is elevated
1, 2, and 3
The lowest PO2 would normally be found in what location?
Cells
What is a normal response of the body to a failure in one component of the acid-base regulatory mechanism?
Compensation
What is the primary chemical event in respiratory acidosis?
Increase in blood CO2 levels
What is the most important component in the oxygen transport system?
Hb
Which airways compose the noncartilaginous airways? I. Subsegmental bronchi II. Bronchioles III. Terminal bronchioles IV. Respiratory bronchioles
II, III, and IV
At what lvl in the tracheobronchial tree are cilia completely absent?
Respiratory bronchioles
Which of the following are potential causes of respiator alkalosis?
- Anxiety
- Central nervous system depression
- Hypoxemia
- Pain
1, 3, and 4
In cm, what is the average diameter of the adult trachea?
2.0-2.5 cm
In acute respiratory acidosis, hat wouldyou expect the BE range to be?
+2 to -2 mEq/L (Normal range)
How does the total cross-sectional area of the tracheobronchial tree change from the trachea to the respiratory zone?
It increases steadily to the terminal bronchioles then increases significantly in the respiratory zone
The highest PCO2 levels are found in what location?
Cells
On what does the movement of gases between the lungs and the body tissues mainly depend?
Gaseous diffusion
A pt has a bicarbonate concentration of 36 mEq and PCO2 of 60mmHg. What is the approximate pH?
7.4
Which of the following accurately describes compensation for acid-base disorders?
Kidneys take hours to days to compensate for respiratory disorders
Which alveolar cells are considered to be te source of pulmonary surfactant?
Type II
Under normal physiologic circumstances, how many milliliters of oxygen are capable of combining wth 1g of Hb?
1.340mL
What type of epithelium is present in the pulmonary capillaries?
Simple Squamous cells
How many second generation bronchi would you find in a healthy adult tracheobronchial tree?
5
When using therapeutic agents that can cause methemoglobinemia, what is important to prevent adverse effects?
Frequent monitoring for methHb to weight the rsk against the benefit
In the face of uncompensated respiratory acidosis, which of the following blood gas abnormalities would you expect to encounter? 1. Decreased pH 2. Increased HCO3- 3. Increased PCO2 4 Increased pH
1 and 3
A pt has a pH of 7.49. What would this define?
Alkalos
The PAO2 depends on which of the following factors?
1. Ambient (atmospheric) pressure
2. Fractional concentration of inspired O2
3. Level of VA
Types of fuels burned (fat, protein, carbohydrate)
1,2,3 and 4
Which of the following would you expect to occur if ventilation to an area o the lung remained constant but perfusion to this same area decreased?
- The PACO2 should fall
- The PAO2 should fall
- The V/Q ratio should rise
1 and 3
Hypoxia is best defined as a condition in which what occurs?
Tissue oxygen delivery is inadequate to meet cellular needs
A pts has aP50 of 30mmHg. What does this indicate?
Decreased affinity of Hb for oxygen
What happens when hte temp. of the blood rises?
- The Hb sat. for a given PO2 falls
- The HbO2 curve shifts to the right
- The affinity of Hb for oxygen increases
1 and 2
In the presence of an acutely reduced arterial oxygen content (hypoxemia), normal oxygen delivery to the tissues can be maintained by which of the following?
Increasing the cardiac output
What does NOT increase the affinity of Hb for oxygen?
Increased temp.
Metabolic acidosis may be caused by:
- An increase in fixed (nonvolatile) acids
- An increase in blood carbon dioxide (CO2)
- Excessive loss of bicarbonate (HCO3)
1 and 3
How is the vast majority of oxygen carried in the blood?
Chemically combined with Hb
What must exist for gas to move between the alveolus and pulmonary capillary?
Diference in partial pressures (pressure grdient)
What is the effect of an elevated intracellular 2,3-DPG concentration?
Increases the availability of oxygen to the tissues
Compensation for metabolic acidosis occurs through which of the following?
Decrease in blood CO2 levels?
What type of epithelium composes 95% of the alveolar surface?
Type I (squamous pneumocyte)
A normal person breathing 100% oxygen at sea level would have PAO2 of about what level?
663mmHg
What is the highest PAO2 one could expect to observe in an individual breathing room air at sea level?
110 to 120 mmHg
Which of the following clinical findings would you expect in a fully compensated respiratory acidosis?
- Elevated HCO3-
- pH below 7.35
- pH between 7.35 and 7.39
- elevated PO2
1 and 3
Which organ system actually excretes H+ from the body?
Kidneys
With partially compensated respiratory alkalosis, which of the following blood gas abnormalities would you expect to encounter?
- Decreased pH
- Decreased HCO3-
- Decreased PCO2
- Increased pH
2, 3, and 4
What is the main compensatory mechanism for metabolic acidosis?
Hyperventilation
What is the primary factor that maintains the pressure gradient that drives oxygen from the capillaries into the interstitial spaces and into the cells?
Cellular consumption of oxygen
How many bronchopulmonary segments are located in the lower lobe of the right lung?
5
What is the normal arterial blood pH range?
7.35-7.45
What condition or treatment could cause iatrogenic respiratory alkalosis?
Mechanical hyperventilation
What is the normal range for BE?
+/- 2mEq/L
Respiratory causes of Respiratory Acidosis
- Acute upper airway obstruction
- Severe diffuse airway obstruction (acute or chronic)
- Massive pulmonary edema
Nonrespiratory causes of Respiratory Acidosis
- Drug overdose
- Spinal cord trauma
- Neuromuscular disease
- Head trauma
- Thoracic trauma
- Gross obesity
Causes of Respiratory Alkalosis
Hypoxemia
Pain
Anxiety
Can be accidentally induced by Pos. Pressure ventilation
Causes of Metabolic Acidosis by increase fixed acids
D.R.I.L.L
D.R.I.L.L.
Diabetic Ketoacidosis (e.g., diabetes/starvation)
Renal failure (distal tubules/retention of H+)
Ingestion of acids (e.g., methanol)
Lactic acidosis (shock/anaerobic metabolism)
Causes of Metabolic Acidosis by loss of base
Road.Hog.Police.Dept (R.H.P.D.)
Renal failure (proximal tubules/loss of HCO3)
Hyperalimentation
Pancreatic fistula
Diarrhea
Causes of Metabolic Alkalosis
H.N.P.D.S.E.
SPENHD
DEPN
- Hypokalemia or hypochloremia
- Nasogastric suction (loss of stomach acid)
- Persistent vomiting (loss of stomach acid)
- Diuretic therapy
- Steroid therapy
- Excessive administration of sodium bicarbonate