Blood Gas Sampling, Analysis, Monitoring,

and InterpretationCRT 7%RRT 6%

The respiratory therapist has just completed an uneventful bronchodilator treatment for a male patient admitted to the hospital after collapsing during a marathon race. The patient suddenly complains of difficulty breathing and chest pain. His heart rate increases from 70 to 115 bpm and he is tachypneic. To further evaluate this patient the therapist should immediately institute:A. Mechanical ventilationB. End tidal CO2 monitoringC. Shunt assessmentD. CPAP therapy at 100%

A 38-week gestation neonate has the following capillary blood gas results:

pH 7.34PCO2 47 torrPO2 43 torrHCO3- 24mEq/L

Which of the following should the respiratory therapist recommend?A. An oxyhood with 50% oxygenB. Mechanical ventilationC. CPAP with nasal prongs at 5 cmH2OD. No therapy is indicated at this time

An arterial blood gas was drawn in the surgical intensive care unit and the syringe was left on the counter for the lab tech to take to the lab. Forty minutes later, the results are recorded as follows?:

pH 7.48PaCO2 24 torrPaO2 100 torrHCO3- 25 mEq/L

Based on these results the respiratory therapist should recommend:A. Institute mechanical ventilationB. Begin bi-level ventilation at an IPAP of 20 cmH2O

and EPAP of 8 CmH2OC. Repeat the arterial blood gasD. Recalibration of the blood gas machine

The following data is available on a recently admitted patient:

HR 88/minRR 18 bpmSaO2 91%A-a gradient 175 torrBS coarse ralesBP 137/88

Based on this information the respiratory therapist should suggest:A. Oxygen therapyB. Mechanical ventilationC. Noninvasive PPVD. Nothing until more information is obtained

During pulmonary rounds in the intensive care unit, the respiratory therapist decides to perform an optimal PEEP study on a patient. The following data is recorded:

Which PEEP level provides optimum benefit for this patient?A. 10 cmH2OB. 15 cmH2OC. 20 cmH2OD. 25 cmH2O

PEEP level

PaO2 C(a-v)O2

HR

0900 10 cmH2O

70 torr 5 cmH2O

88 bpm

0930 15 cmH2O

85 torr 5 cmH2O

78 bpm

1000 20 cmH2O

93 torr 7 cmH2O

89 bpm

1030 25 cmH2O

100 torr 10 cmH2O

95 bpm

To increase a low PaO21. Increase FiO2 by 5-10% (up to 60%)2. Increase PEEP by 2-5 cmH2OUntil:3. Acceptable oxygenation is achieved, or4. Unacceptable side-effects occur

1. ↓ compliance2. ↓ cardiac function3. Barotrauma4. ↑ C(a-v)O2

O Closed head injury or low BP: Increase FiO2 instead of PEEP. Keep pressures low!

A 30-year-old-male patient is receiving volume control ventilation due to complications of a surgical procedure to drain a lung abscess. The patient weighs 98 kg (215 lb) and is 6 feet (185 cm) tall. His ventilator settings are: SIMV mode, Vt 830 mL, set f 14 bpm, total f 15 bpm, FiO2 0.4. Arterial blood gases drawn after thirty minutes show the following:

pH 7.46PaCO2 32 torrPaO2 90 torrHCO3- 21 mEq/L

Which of the following should the respiratory therapist recommend at this time?A. Maintain current settingsB. Administration of bicarbonateC. Add mechanical dead spaceD. Decrease frequency

To normalize a low PaCO2

O Decrease respiratory rateO Decrease tidal volumeO Increase deadspace

O Target PaCO2 for closed head injury patients should be 25-30 torr

A 74 kg (163 lb) male patient has been on volume control ventilation for the past four days at the following settings: A/C mode, Vt 700 mL, set f 10 bpm, total f 10 bpm, FiO2 0.6. The most recent arterial blood gas data is recorded as follows:

pH 7.34PaO2 61 torrPaCO2 52 torr HCO3- 28 mEq/L

Which of the following should the respiratory therapist recommend?1. Increase frequency to 14 bpm2. Switch to SIMV mode3. Increase FiO2 0.654. Add 5 cmH2O of pressure support

A. 1 and 4B. 2, 3, and 4C. 1 and 3D. 2 and 4

To normalize a high PaCO2

O Decrease or remove deadspaceO Increase tidal volumeO Increase the respiratory rate

A 24-year-old male patient is in the Emergency Department after being involved in a motor cycle accident. It is estimated the patient is 5 foot 10 inches (178 cm) tall and weighs 80 kg (176 lb). After a quick bedside assessment the patient is intubated and placed on volume control ventilation at the following settings: SIMV mode, f 10 bpm, Vt 770 mL, FiO2 0.6, PEEP 10 cmH2O. After twenty minutes his arterial blood gas shows the following results:

pH 7.39PaO2 51 torrPaCO2 36 torr HCO3- 24 mEq/L

Which of the following should the respiratory therapist recommend?A. Increase tidal volume to 800 mLB. Switch to assist control modeC. Increase the FiO2 to 0.7D. Increase PEEP to 15 cmH2O

A 65 kg (143 lb) female patient is in the surgical intensive care unit after surgery to relieve a sub-arachnoid hemorrhage. She is on volume cycled ventilation at the following settings: A/C mode, set f 12 bpm, total f 12 bpm, Vt 800 mL, FiO2 0.4. Available arterial blood gas information is recorded as:

pH 7.34PaO2 85 torrPaCO2 46 torr HCO3- 22 mEq/L

After reviewing the data the respiratory therapist should recommend:A. Increase the tidal volumeB. Increase the frequencyC. Add PEEPD. Add mechanical dead space

While performing quality control procedures on a blood gas machine, it is determined that the PCO2 electrode has a mean value of 32 torr. The next three control run values are recorded as 31 torr, 37 torr, and 34 torr. Which of the following would best explain these results?A. In controlB. Out of controlC. Random errorD. Displaying a trend