The first arterial blood gas for an asthma patient in the ...

[stephzh]

The first arterial blood gas for an asthma patient in the emergency department reveals: pH 7.49; PaCO2 30; PaO2 82; SaO2 95; HCO3 24 on a nasal cannula 3 L/min.
 
  The patient's peak expiratory flow rate was 165 L/min, respiratory rate was 16 breaths/min, and pulse 106 beats/min. After continuous aerosolized albuterol over the past hour, the patient's cur-rent ABG results are as follows: pH 7.34; PaCO2 45; PaO2 49; SaO2 79; HCO3 25 on a high flow nasal cannula 15 L/min. The patient's peak expiratory flow rate is 95 L/min, respiratory rate 35 breaths/min, pulse 128 beats/min, and the patient is diaphoretic. The respiratory therapist should suggest which of the following at this time?
  a. Change to a nonrebreather mask.
  b. Begin continuous positive airway pressure.
  c. Intubate and initiate mechanical ventila-tion.
  d. Initiate noninvasive positive pressure ven-tilation.

Question 2

A 64-year-old female patient having an acute exacerbation of chronic obstructive pulmonary dis-ease (COPD) was admitted to the hospital yesterday.
 
  During rounds today the respiratory therapist finds the patient to be difficult to arouse and has the following physical findings: heart rate 102 beats/min, respiratory rate 23 breaths/min shallow and slightly labored, breath sounds are bilaterally decreased with rhonchi in both bases. The pa-tient has a frequent but weak cough. The respiratory therapist draws an ABG with the following results on a 2 L/min nasal cannula: pH 7.52, PaCO2 30 mm Hg, PaO2 45 mm Hg, SaO2 86, HCO3 24 m Eq/L. The most appropriate action is which of the following?
  a. Intubate and mechanically ventilate.
  b. Increase the nasal cannula to 4 L/min.
  c. Administer incentive spirometry.
  d. Begin noninvasive positive pressure venti-lation.

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Answer to Question 1

ANS: C
This patient's airway obstruction is worsening as evidenced by the deterioration in the patient's acid-base status, oxygenation status, and peak expiratory flow rate. The patient has also devel-oped tachycardia, tachypnea, and sweating. The critical values are partial pressure of oxygen in the arteries (PaO2), peak expiratory flow rate (PEFR), respiratory rate (RR), and pulse. This pa-tient is now in impending ventilatory failure and meets the standard criteria for instituting me-chanical ventilation (see Box 4-5). Changing oxygen delivery devices to a nonrebreather mask will not increase the fractional inspired oxygen (FIO2) delivered. Continuous positive airway pressure may address the patient's oxygenation problem; however, it will not help to improve the patient's increased work of breathing.

Answer to Question 2

ANS: B
It would be inappropriate to intubate or use noninvasive positive pressure ventilation (NPPV) on this patient at this time because the patient is able to move air, as evidence by the partial pressure of carbon dioxide (PaCO2) of 30 mm Hg in the arteries. This patient might benefit from lung ex-pansion therapy. However, she would not be able to cooperate to perform the incentive spirome-try properly because she is difficult to arouse. The patient would benefit from an increase in ox-ygen therapy by increasing the nasal cannula flow to 4 L/min since her partial pressure of oxygen in the arteries (PaO2) is 45 mm Hg on 2 L/min nasal cannula. When the 2 L/min is estimated to be approximately 28 oxygen the PaO2/FIO2 is 161. This is a critical value. This patient would also benefit from bronchial hygiene therapy to mobilize the retained secretions.

[stephzh]

Correct answers!

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