A 36-year-old female patient with a history of asthma is admitted ...

[Bernana]

A 36-year-old female patient with a history of asthma is admitted to the ICU from the emergen-cy department. Her respirations are 30, very labored, with accessory muscle use and bilateral in-spiratory and expiratory wheezing.
 
  There is bilateral hyperresonance during chest percussion. A blood gas taken in the ICU after 1 hour of continuous aerosolized albuterol (15 mg) reveals: pH 7.38, partial pressure of carbon di-oxide (PaCO2) 42 mm Hg, partial pressure of oxygen (PaO2) 53 mm Hg, oxygen saturation (SaO2) 88, bicarbonate (HCO3) 25 mEq/L with nasal cannula 6 L/min. The patient is 5'5 and weighs 135 lb. The most appropriate action at this time is which of the following?
  a. Continue current therapy with 20 mg al-buterol and reassess in 1 hour.
  b. Noninvasive positive pressure ventilation (NPPV) with bilevel positive airway pres-sure (bilevel PAP), f = 12, inspiratory pos-itive airway pressure (IPAP) 28 cm H2O, expiratory positive airway pressure (EPAP) 3 cm H2O, fractional inspired ox-ygen (FIO2) 0.30
  c. Intubate, use pressure-controlled continu-ous mandatory ventilation (PC-CMV), f = 8, peak inspiratory pressure (PIP) 28 cm H2O, TI 0.75 seconds, positive end-expiratory pressure (PEEP) 3 cm H2O, FIO2 1.0
  d. Intubate, use volume-controlled continu-ous mandatory ventilation (VC-CMV), f = 12, tidal volume (VT) 600 mL, PF 40 L/min, PEEP 5 cm H2O, FIO2 0.60

Question 2

During mechanical ventilation, a patient with a closed head injury develops the Cushing re-sponse. This may be immediately managed by using which of the following?
 
  a. Pressure-controlled continuous mandatory ventilation (PC-CMV) with positive end- expiratory pressure (PEEP)
  b. Sedation and paralysis
  c. Permissive hypercapnia
  d. Iatrogenic hyperventilation

[makaylafy]

Answer to Question 1

ANS: C
The assessment and arterial blood gases (ABG) for this patient reveal impending respiratory fail-ure. This patient should be intubated and may possibly require sedation and paralysis, depending on the ability to ventilate with synchrony. Therefore, continuation of the current therapy is not appropriate. Noninvasive positive pressure ventilation (NPPV) is not appropriate with asthma pa-tients who are in respiratory failure and may be unable to provide airway protection. The settings for the volume-controlled continuous mandatory ventilation (VC-CMV) are not appropriate be-cause the tidal volume is set too high, the frequency too low, and the peak flow too low. This would not allow enough time for exhalation and may cause barotrauma. The pressure-controlled continuous mandatory ventilation (PC-CMV) mode will allow for more control over the pres-sures. The short expiratory time will allow time for exhalation that will decrease the likelihood of hyperexpansion of the lungs.

Answer to Question 2

ANS: D
The Cushing response is the normal response to acute increases in intracranial pressure (ICP). This includes hypertension with bradycardia. Iatrogenic hyperventilation, although controversial, is recommended when there is acute uncontrolled increased ICP. The partial pressure of carbon di-oxide in the arteries (PaCO2) should be maintained between 25 and 30 mm Hg or titrated to the ICP if it is being monitored. This is a temporary solution and should be gradually reversed within 24-48 hours, allowing acid-base balance to restore itself. The use of pressure-controlled continu-ous mandatory ventilation (PC-CMV) and positive end-expiratory pressure (PEEP) can increase ICP further. Sedation and paralysis should only be used in extreme cases when the ventilator and patient are asynchronous (usually with severe asthma). Permissive hypercapnia may result in fur-ther increases in ICP.

[Bernana]

TYSM

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