terms of mechanical ventilation 9th edition

16.The first arterial blood gas for an asthma patient in the emergency department reveals: pH 7.49; partial pressure of carbon dioxide (PCO2) 30; partial pressure of oxygen (PO2) 82; oxygen saturation (SO2) 95%; bicarbonate (HCO3-) 24 on a nasal cannula 3 L/min. The patient’s peak expiratory flow rate was 165 L/min, respiratory rate was 16, and pulse 106. After continuous aerosolized albuterol over the last hour patient’scurrent arterial blood gas results are as follows: pH 7.34; PCO2 45; PO2 49; SO2 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, pulse 128, 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 ventilation. d.Initiate noninvasive positive pressure ventilation. 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 developed 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 patient is now in impending ventilatory failure and meets the standard criteria for instituting mechanical 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. DIF: 3 REF: pg. 54 17.A patient seen in the emergency department exhibits paralysis of the lower extremities that is getting progressively worse. Vital capacity is 6 mL/kg, maximum inspiratory pressure (MIP) is -17 cm H2O, and oxygen saturation measured by pulse oximeter (SpO2) is 89%. Arterial blood gases (ABGs) are pending. The physician suspects Guillain-Barré syndrome. The most appropriate action at this time is which of the following? a.Intubate and mechanically ventilate. b.Place patient on a nonrebreather mask. c.Initiate continuous positive airway pressure. d.Initiate noninvasive positive pressure ventilation. ANS: A This patient’s maximum inspiratory rate (MIP) and vital capacity (VC) measurements are both critical. Since that patient has a progressive neuromuscular disease with these critical values and a below normal pulse oximetry reading, this patient should be intubated and mechanically ventilated before the patient develops an acute situation. Placing the patient on a non-rebreathing mask or initiating continuous positive airway pressure (CPAP) will not address the fact that the neuromuscular disease is now beginning to affect this patient’s ventilator muscle strength. Since protection of the airway may become an issue, invasive ventilation would be the most appropriate action. DIF: 3 REF: pg. 52| pg. 53 18.Which of the following values are indicative of acute respiratory failure and the need for ventilatory support? 1.Maximum inspiratory pressure (MIP) = -38 cm H2O 2.Vital capacity (VC) = 650 mL for a 70 kg male 3.Alveolar-to-arterial partial pressure of oxygen [P(A-a)O2] = 150 on 100% oxygen 4.Maximum expiratory pressure (MEP) = 25 cm H2O a.1 and 2 only b.2 and 4 only c.1 and 3 only d.3 and 4 only ANS: B The critical values for the parameters listed are: maximum inspiratory pressure (MIP) -20 to 0, vital capacity (VC) < 10 to 15 mL/kg ideal body weight (IBW), alveolar to arterial partial pressure [P(A-a)O2 ] > 450 on O2, and maximum expiratory pressure (MEP) < 40 cm H2O. DIF: 2 REF: pg. 52; Tables 4-2 and 4-3 19.The disorders that cause respiratory failure due to increased work of breathing include which of the following? 1.Myasthenia gravis 2.Cardiogenic pulmonary edema 3.Interstitial pulmonary fibrosis 4.Amyotrophic lateral sclerosis a.1 and 2 only b.2 and 3 only c.3 and 4 only d.1 and 4 only ANS: B Myasthenia gravis and amyotrophic lateral sclerosis are two neuromuscular disorders that cause respiratory failure through muscle weakness and paralysis. Both cardiogenic pulmonary edema and interstitial pulmonary fibrosis cause respiratory failure through increased work of breathing. DIF: 1 REF: pg. 53 20.A 52-year-old male with a medical history of congestive heart failure and hypertension arrives in the emergency department because of an acute onset of dyspnea. The patient has pink frothy secretions at the mouth. A rapid physical assessment reveals a pulse of 128, respiratory rate 28 breaths/min and labored, and blood pressure 82/56 mm Hg. Bilateral coarse crackles are heard in the lung bases. Arterial blood gas results on a 12 L/min nonrebreather mask are: pH 7.32, partial pressure of carbon dioxide (PaCO2) 49 mm Hg, partial pressure of oxygen (PaO2) 50 mm Hg, arterial oxygen saturation (SaO2) 74%. The most appropriate immediate action for this patient is which of the following? a.Intubation and mechanical ventilation b.Increase flow to the nonrebreather mask c.Continuous positive airway pressure via mask d.Nasotracheal suctioning and a high flow nasal cannula ANS: A This patient is hypoxemic with a nonrebreather mask and is also unable to move a sufficient amount of air. This is evidenced by the patient’s partial pressure of oxygen in the arteries (PaO2) of 50 mm Hg and partial pressure of carbon dioxide in the arteries (PaCO2) of 49 mm Hg. Three out of the four oxygenation criteria are below the critical values. The pink frothy sputum is cardiogenic pulmonary edema and the hypotension is caused by cardiogenic shock. This is a medical emergency requiring intubation, mechanical ventilation, and positive-end-expiratory pressure (PEEP). Increasing the flow of oxygen to the nonrebreather, continuous positive airway pressure (CPAP) via mask, nasotracheal suctioning and a high flow nasal cannula will not reverse this patient’s oxygenation or ventilation