Initiation and Modification of Therapeutic Procedures Evaluate and Monitor Patient’s Objective and Subjective Response to Respiratory Care

 Includes basic noninvasive and invasive procedures, and assessment techniques the NBRC expects you to apply when evaluating a patient’s response to therapy  Techniques are also the foundation for you to independently modify therapeutic procedures, recommend modifications in the care plan, and determine the appropriateness of therapy.

Recommend and Review Chest Radiographs You should recommend a chest X-ray to  Locate lines, catheters, and tube position  Assess disease progression  Identify any pathologic lung or chest abnormalities On the NBRC Exam, X-ray findings are in the form of written interpretation.

Obtain a Blood Gas Sample Arterial blood gasses are obtained to:  Evaluate ventilation (PaCO2), acid-base (pH), and oxygenation (PaO2 and SaO2) status, including O2-carrying capacity (HbO2, total Hb, and abnormal Hb)  Monitor and assess the patient’s response to therapy and/or diagnostic tests and procedures  Monitor severity and progression of a documented disease process. You should know the proper procedure for obtaining arterial blood via arterial puncture, arterial lines (pulmonary and systemic), and capillary puncture. In the NBRC hospital you may be responsible for the insertion and care of arterial lines.

Perform Blood Gas and Co-Oximetry Analysis To ensure accurate and reliable results you must be familiar with procedures for:  Sample analysis  Sample and equipment troubleshooting  Equipment maintenance and calibration  Quality control measures

Interpret Blood Gas and CO- Oximetry Results Blood Gas Analysis  Assessing PaCO2 and BE can help you quickly identify if compensation is occuring  Compensation is occurring if both the PaCO2 and BE are abnormally high or low  If both are high the patient has either a compensated metabolic alkalosis, or compensated respiratory acidosis  If both are low, the patient has either a compensated metabolic acidosis or compensated respiratory alkalosis  If go in opposite directions then a combined acid-base disorder exists  pH determines primary disturbance and degree of compensation

Assessing Arterial Oxygenation PaO2 and SaO2 results must be compared against the FiO2 the patient is receiving when sample was taken. Two common formulas used are  The alveolar-arterial O2 tension gradient (PAO2 – PaO2)  Normal P(A-a)O2 difference on room air is about 5 – 10 torr  Normal P(A-a)O2 on 100% is about 25 – 65 torr  When the FiO2=1.0, every 100 torr of P(A-a)O2 corresponds to about 5% shunt  The ratio of PaO2 to FiO2 (PaO2/FiO2 or P/F ratio)  Normal P/F ratio exceeds 350 – 450  A P/F ratio < 300 indicates moderate disturbance of oxygenation (acute lung injury)  A P/F ratio < 200 indicates a severe disturbance consistent with ARDS  rule: If the PaO2 is 0.6, then there is a severe disturbance in oxygenation mainly due to shunting.

CO-Oximetry Results Interpretation  Elevated blood HbCO levels can be caused by exposure to tobacco smoke, faulty gas furnaces, auto exhaust, or smoky fires. In these situations pulse oximetry will read falsely high and should not be used to assess hypoxia.  Elevated methemoglobin may be hereditary or acquired through exposure to certain chemicals (nitrates, nitrites, chlorates, quinones, aminobenzenes, nitrobenzenes, or nitrotoluenes) or drugs (benzociaine, nitroglycerin, nitroprusside).  An SaO2 less the 85% indicates significant hypoxemia  If the sum of the abnormal hemoglobins exceeds 15%, the oxygen carrying capacity of the blood is severely diminished.  Elevated bilirubin levels will lead to falsely high total Hb, HbO2, and metHb levels.

Perform Pulse Oximetry Should be initially correlated with CO-oximetry analysis of baseline arterial sample. Help to ensure accuracy by correlating patient pulse rate with pulse oximeter data. Common source of error and false alarms with pulse oximetry is motion artifacts.  Below 90% indicates need for supplemental oxygen  Significant declines (>5%) during exercise or sleep are abnormal

Perform Capnography Remember to  Calibrate the monitor according to the manufacturer’s instructions  Connect the monitor to the patient’s airway and observe the CO2 waveform  Compare the monitor reading with current ABG values  In healthy individuals PETCO2 averages 1 – 5 torr less than PaCO2  Consistent, close correlation of results is needed if the monitor is to provides useful information regarding changes in ventilation  Know causes of sudden or gradual changes in results.

Measure and Record Vital Signs and Cardiac Rhythm and Evaluate Fluid Balance Monitor Cardiac Rhythm The most common dysrhythmias on the NBRC CRT exam include:  Lethal Rhythms  Asystole  Ventricular tachycardia  Ventricular fibrillation  Non-lethal Rhythms  Atrial fibrillation  Atrial flutter  Bradycardia  Tachycardia  Premature ventricular contractions

Perform and Interpret Results of Pulmonary Function Testing NBRC expects you to also be familiar with bronchoprovocation studies used to identify and assess airway responsiveness. Recommend a bronchial challenge test to  Differentiate asthma from chronic bronchitis  Quantify the severity of airway responsivenes  Screen individuals who may be at risk from environmental or occupational exposure to allergens  Indentify exercise-induced bronchospasm

Observe Changes in Sputum Characteristics NBRC expects you to relate the characteristics of the patient’s sputum to the need for specific diagnostic tests or treatments:  Mucopurulent or purulent sputum  Indicate infection  Recommend chest X-ray, gram stain and culture and sensitivity testing  Pink, watery, frothy sputum with signs / symptoms of heart failure  Indicative of acute pulmonary edema  Recommend high concentrations of oxygen, ideally with CPAP or BiPAP

Observe for Signs of Patient- Ventilator Asynchrony When a patient’s spontaneous respiratory efforts are no longer in synchrony with that of the ventilator. Most common manifestations include agitation and respiratory distress. Patient-related problems:  Partial or complete airway obstruction  Bronchospasm, pulmonary edema, pneumothorax, anxiety, pain Ventilator-related problems:  Inadequate or inappropriate settings

Monitor and Assess Airway Pressures  Peak Inspiratory Pressure (PIP)  Inspiratory pause (or Plateau) Pressure  NBRC hospital expects you to interpret changes or trends in PIP and Pplat over time.  Compliance  Airway resistance  Expiratory Pause Pressure  Mean Airway Pressure  Maximum Inspiratory and expiratory pressures (weaning readiness)

Measure FiO2 and/or Liter Flow All O2–delivery systems should be checked at least once per day. More frequent checks using a calibrated O2 analyzer should be performed on O2 systems that are:  Susceptible to variation in O2 concentration  Applied to patients with artificial airways  Delivering a heated gas mixture  Applied to patients who are clinically unstable or require an FiO2 of 0.50 or greater.

Common Errors to Avoid on the Exam  Do not perform an Allen test when drawing an ABG from the brachial artery site. There is not collateral circulation to assess for this artery.  Avoid placing O2 analyers distal to a heated humidifier in ventilator circuits; humidity and water vapor pressure may affect the analyzer’s readings.  Avoid performing a capillary blood test in a neonate less than 24 hours old  Avoid radial punctures for ABGs if the Allen is negative. Repeat the test on the opposite hand. If still negative, use the brachial artery.

More Common Errors to Avoid on the Exam  Avoid drawing blood from a distal port of a pulmonary catheter too fast or the balloon inflated since it may contaminate the sample with arterial blood.  Do not use pulse oximetry to asses oxygenation in a patient suspected of carbon monoxide (CO) poisoning due to smoke inhalation. The SpO2 will read falsely high. Recommend CO- oximetry instead.  Do not evaluate a patient’s minute ventilation alone. Always assess for proper VT and rate in conjunction with the minute ventilation  Do not use a capillary blood gas test to assess oxygenation status

Exam Sure Bets  Always target hemoglobin saturation above 90-92% in order to maintain proper tissue oxygenation.  Always use pressure monitor alarms for acutely ill patients receiving noninvasive positive pressure ventilation or those requiring long-term 24-hour support.  During volume control ventilation, an increase in set flow rate will cause an increase in the peak inspiratory pressure and vice versa. Manipulation of the flow will also affect inspiratory times and I:E ratios.  Always warm up the site for a capillary blood test before performing the puncture to allow for vasodilation and arterialization of the blood.

More Exam Sure Bets  The most efficient breathing pattern is slow, deep breathing  During A/C volume-cycled ventilation, changes in the tidal volume, rate, and flow will affect the I:E ratio.  A healthy adult patient receiving 100% O2 at sea level should have a PaO2 of about 650 torr.  When assessing changes on PIP during volume- controlled ventilation always evaluate the plateau pressure to determine if change in resistance or a change in compliance is the primary cause.  Always set the high/low CPAP/PEEP pressure alarms at + /- 3-5 cm H2O above and below set pressure.

More Exam Sure Bets  Always confirm SpO2 accuracy by correlating the heart rate, assessing pulse strength, and evaluating the SpO2 wave form.  When interpreting blood gases, always assess ventilation (pH, PaCO2) and oxygenation (PaO2, SaO2) separately.  Always perform an Allen test when drawing an ABG from the radial artery site.  Normal breath sounds heard at abnormal locations are always an abnormal finding.  Always use a chest radiograph (or bronchoscopic visualization) to confirm proper placement of an endotracheal tube; use bilateral breath sounds and a positive CO2 colorimetry reading only as a preliminary indicator of proper placement.

Reference: Certified Respiratory Therapist Exam Review Guide, Craig Scanlon, Albert Heuer, and Louis Sinopoli Jones and Bartlett Publishers