Question

Mr. S. is a retired 69-year-old county attorney who was on a buying trip with his wife for old, classic cars in the high, mountainous country of Colorado when he became extremely short of breath. His alarmed wife took him to a multispecialty medical clinic for evaluation. On admission to the clinic, Mr. S. was restless and dyspneic. His chest had an increased anteroposterior dimension.

Mr. S.'s history revealed a habit of smok­ing 2 packs of cigarettes a day for 45 years. Dur­ing the past few years, Mr. S. had noticed a cough each morning on arising. Recently, while working in his flower garden, he had to stop at times to catch his breath. Even while watching television, he had experienced dyspnea. Also, he indicated a weight loss over the last 2 months.

A chest radiograph was taken, and pul­monary function tests were done. The chest radiograph revealed a flat, low diaphragm with lung hyperinflation but clear fields. Pulmonary func­tion tests showed decreased tidal volume and vital capacity, increased total lung capacity, and prolonged forced expiratory volume.

Mr. S’s condition deteriated and he was admitted to the hospital. On assessment, his Pulse oximeter indicated a reading of 89%. The nurse is aware that the pulse oximeter value is important but she knows that it is limited because it only measures one component of oxygenation. In order to have a more accurate picture of Mr. S’s overall oxygenation status, the nurse must assess ABGs and pulse oximeter values in relations to the Oxyhemoglobin dissociation curve.

Mr. S’s condition deteriated and he was admitted to the hospital. On assessment, his Pulse oximeter indicated a reading of 89%. The nurse is aware that the pulse oximeter value is important but she knows that it is limited because it only measures one component of oxygenation. In order to have a more accurate picture of Mr. S’s overall oxygenation status, the nurse must assess ABGs and pulse oximeter values in relations to the Oxyhemoglobin dissociation curve. The ABG values were ph 7.30, pO₂ 80, pCO₂ 50, HCO3 26mEq/L.   

Mr. S was initially placed on nasal O2 @ 6 L and his pO2 was 76. As his condition declined, the nasal O2 administration was increased. Mr. S was later placed on a ventilator with positive pressure and PEEP. Which condition did it progress to? Justify your answer. (First Diagnosis was COPD, BUT NEED WHAT HE PROGRESSED INTO). Define P 50 and why is the value important?

Answer 1

Mr.s is progress to Hypoxemia
Because it indicate lowered blood oxygen content..Alkalosis or alkalemia is a term which refers to excessive amount of acid in the blood..if our blood acid levels are high it will distrub anyone health..Normal PH value 7.35 to 7.45 when PH level goes below 7.35 it is acidemia and above 7.45 it is alkalemia..When lungs are not function properly co2 builds up increased carbonic acid..This can affect the blood PH leads to acidosis..
   Due to hyperventilation co2 level will reduce..because of reduction of co2 causes theblood PH to become less acid..reduced co2 level and the acid level there will be excess acid in the blood..pco2 increased due to hypoventilation and decreased due to hyperventilation..If PH level below 7.35 and co2 level more than 45mmhg indicate respiratory acidosis..
Oxygen saturation can remain at 85% to 90% when po2 reaches low to 50 and 60mmhg..When it go above 70 patient will maintain oxygen saturation between 80-100%..patient with respiratory disease danger with low oxygen levels and high co2levels..
P50-oxygen tension at 50% hemoglobin saturation
The desirable p50 response to hypoxia,drugs and hemoglobin substitutes can alter the p50 value.so manipulating p50 when tissue oxygen delivery is under threat..so the p50 which best preserves mixed venous oxygen tensions is the appropriate defense of mitochondrial oxygenation..
Oxyhemoglobin dissociation curve:
   this having relationship between o2 tension of blood and oxygen saturation..p50 is the oxygen tension when hemoglobin is 50% saturated with o2..when hemoglobin-oxygen affinity increases,the oxyhemoglobin dissociation curve shifts to the left and decreases p50,when it go to right it increases p50..
when oxygen is not enough for the patient pco2 rises,PH falls and the curve shifts to the right..to find out the particular data it remains to be established that manipualtions of p50 in critical illness can improve gas exchange,tissue oxygenation or outcome.To get better evidence this p50 status important for routine quantification and consideration..