Question

Auto Injury : A Case Study in Acid-Base Balance

Mr. Wilson , a 60-year-old male, was on his way home from work after snowing all day. Mr. Wilson slide on the icy street through a red light where he was hit by an oncoming truck. The other driver suffered only minor bruises and cuts, Mr. Wilson demonstrated labored breathing and severe chest pain. Mr. Wilson was in the trauma centers ER in less than 2 mins. Mr. Wilson had experienced blunt trauma from the impact of the steering wheel after the airbag failed to deploy.

Mr. Wilson examination revealed, blurred vision, dizziness, headache, nausea, muscle weakness, hypoventilation, and a feeling of mental confusion. A Ct scan revealed bilateral fractures in the fourth, fifth, and six ribs and a possible hemothorax. An ECG revealed signs of ventricular arrhythmias. The values following values were taken from the results of an arterial blood gas (ABG) and urinalysis (UA).

Aterial Blood Gas (ABG)     High or Low

pH:                  7.1                        Low

P_co2:                          58                         High

bicarbonate:    33 mEq/L             High          

Urinalysis (UA)

pH:                  3.7                        Low

Short Answer Questions

1. Define the following terms contained in this case:
   1. Bilateral
   2. Hypoventilation
   3. Hemothorax
   4. Arrhythmias

2. What are the normal ranges for the measurements listed in the blood and urine tests?

3. Explain how Mr. Wilson’s rib fractures are related to the suspected hemothorax.

4. Mr. Wilsons’s P_CO2 is elevated. Under normal conditions, what would be the PRIMARY mechanism that his body would use to reduce the amount of P_CO2 in the blood? Why is this mechanism not working in this case?

5. Describe how the high P_CO2 and low pH in Mr. Wilson’s blood are related in this case.

6. Describe how the high bicarbonate in Mr. Wilson’s blood is related to the low pH in his urine.

7. What type of intervention might the doctors and nurses initiate in order to address the hemothorax? Explain how this intervention will lead to changes in P_CO2 and blood pH.

Answer 1

1.bilateral - involving both sides

hypoventilation - slow breathing due to accumlation of co2

Hemothorax - presence of blood in the pleural cavity

Arrhythmias-abnormal ecg waves

2.normal abg values

PH of blood - 7.35 to 7.45

Pco2 - 35 to 45 mmhg

Bicarbonate - 22 to 27 meq/l

Normal urine ph - 4.5 to 8

3.the ribfracture may damage lungs or intercostal blood vessels causing hemothorax.

4.increase in pco2 cause hyperventilation increasing respiratory rate and balence this.its the primary mechanism.

In this case hyperventilation not possible due to rib fracture.