End-Tidal Carbon Dioxide Monitoring
6. The graduate nurse is caring for an intubated infant receiving mechanical ventilation. The nurse preceptor is educating the graduate nurse on setting up equipment for continuous ETCO2 monitoring. What statement by the graduate nurse indicates that the teaching was effective?
"Sidestream analyzers use a sampling line connected to a T-piece adaptor at the ET tube opening." Rationale: Sidestream capnometers (diverted to a monitor) use a sampling line that attaches to a T-piece adapter at the ET or tracheostomy tube opening, which allows continuous aspiration of tidal airway gas for analysis of carbon dioxide. Connecting the capnograph into a wall outlet and attaching the cable to the monitor should happen after calibration is completed. Monitor alarms should be set according to the practitioner's orders or child's developmental level to include respiratory rate, apnea default, and high and low ETCO2 levels. A gradual increase in the waveform plateau level indicates increasing ETCO2 levels and would not be a normal finding.
8. The nurse is caring for an intubated adolescent receiving mechanical ventilation. The family member asks the nurse about the ETCO2 value and waveform on the monitor. What would be the best response by the nurse?
A. "It is important to monitor the carbon dioxide to make sure the breathing tube is in the right place." Rationale: Monitoring ETCO2 is useful in confirming ET tube placement, detecting inadvertent esophageal intubation, and detecting life-threatening conditions, such as displacement of the ET tube, impending ventilatory failure, and circulatory failure. Capnography may be used as an adjunct to pulse oximetry and clinical assessment to detect hypoventilation and apnea early in children undergoing procedural sedation and anesthesia. ETCO2 monitoring may be used to evaluate the effectiveness of chest compressions with a goal of an ETCO2 value of 10 to 15 mm Hg in children. When capnography is used and CPR is not being performed, the normal ETCO2 value is 35-45 mm Hg.
7. The nurse is caring for an intubated infant receiving mechanical ventilation. During an assessment, the nurse notices that the waveform has suddenly dropped and that there is a sudden decrease in the ETCO2 level to near zero. What is the nurse's first step?
Assess the child's respiratory status and notify the practitioner. Rationale: A sudden drop in the waveform to baseline or near zero indicates that no respirations are present and can occur with a pulmonary embolus because there is a significant change in the ventilation-to-perfusion ratio. It is important that the nurse notify the practitioner so interventions can be implemented immediately. Oral suctioning may clear excess secretions in the mouth and decrease the risk of infection but would not be a priority in this situation. Increasing the amount of oxygen would not be beneficial if there is a ventilation-to-perfusion mismatch caused by a pulmonary embolus.
1. The nurse is caring for an intubated child receiving mechanical ventilation. The ETCO2 begins to slowly rise from 42 to 54 mm Hg. What intervention would be the most appropriate?
Assess the child's work of breathing and breath sounds. Rationale: The nurse should always first assess the child when there is any change in vital signs. The additional assessment data can be shared with the practitioner to provide more complete data about any changes in the child's condition (e.g., absent breath sounds, diminished on one side). Most likely, the nurse will be asked to draw a sample for blood gas analysis to compare the PaCO2 to previous values and assess the child's condition based on laboratory work as well. The nurse should still document the change in the child's record, but intervening later may not be a good choice in this situation.
9. A child has been orally intubated by the practitioner. After connecting the ETCO2 monitor to the ET tube, the nurse observes that the capnograph waveform is suddenly decreased, and the ETCO2 level is 17 mm Hg despite manual ventilations with a bag device. What should the nurse suspect?
Esophageal intubation Rationale: A low ETCO2 level with a sudden decrease in waveform despite manual ventilations through a bag device following intubation typically indicates an inadvertent esophageal intubation. Metabolic acidosis would cause a gradual decrease in ETCO2 with a normal waveform. Intubation in the right mainstem bronchus would not cause a decrease in ETCO2. Neuromuscular blockade would cause an increased ETCO2.
10. While caring for an intubated adolescent receiving mechanical ventilation, the nurse notices that the capnograph waveform is elevated above the baseline. What should the nurse suspect?
Incomplete exhalation Rationale: An elevated capnograph waveform above the baseline typically indicates rebreathing, which may result from incomplete inhalation or exhalation or excessive dead space in the ventilator circuit. A pulmonary embolus would result in a sudden decrease in ETCO2 and waveform to or below the baseline, at around zero. Hyperthermia would result in a gradual increase of the waveform plateau level.
3. The nurse is caring for an intubated child receiving mechanical ventilation. During an assessment, the nurse observes that the ETCO2 has slowly risen from 42 to 53 mm Hg. The child's capnograph shows a gradual increase in the trends graph. Which intervention is the most appropriate?
Intervening to decrease the carbon dioxide Rationale: Intervening to decrease the carbon dioxide is the most appropriate next step. The child needs more gas exchange with each breath, which would decrease the carbon dioxide. Although suctioning the mouth would decrease the incidence of infection, secretions might be obstructing the ET tube and may increase carbon dioxide, so suctioning and clearing the secretions in the ET tube would be more appropriate. Decreasing the rate on the ventilator allows for fewer breaths to be delivered to the child, thereby increasing the carbon dioxide. Administering a paralytic would cause the child to not breathe over the ventilator rate, which would lead to increased carbon dioxide levels.
4. During the assessment of an intubated child receiving mechanical ventilation, the nurse notices that the child has become more agitated, and the ETCO2 has suddenly decreased from 38 to 22 mm Hg with a decrease in the waveform. What would be the most likely cause?
The child is biting the ET tube. Rationale: A sudden decrease in ETCO2 to a lower value with a decreased waveform often indicates malposition of the ET tube or a partial obstruction of the tube, such as the child biting it. A pulmonary embolus can also cause a sudden drop in ETCO2 but the value would be around zero and the waveform would be the baseline or lower, indicating no respirations are present. Hypovolemia would cause a gradual decrease in ETCO2 with a normal waveform. Sepsis would cause a gradual increase in ETCO2with a normal waveform.
2. While caring for an intubated child on a ventilator, the nurse observes that the ETCO2 has slowly risen from 42 to 55 mm Hg. The child's capnograph shows a gradual increase in the trends graph. What do these findings indicate?
The child is being hypoventilated. Rationale: The child is retaining carbon dioxide, which is causing a slow rise in the trends. If the child were being hyperventilated, the trends would slowly decrease rather than increase. Impending circulatory arrest and pulmonary embolism would cause an exponential decline in graph trends rather than an increase.
5. An adolescent is intubated for a decrease in level of consciousness. The capnograph shows a loss of plateau and decreased ETCO2. What reportable condition is associated with that waveform?
The adolescent is experiencing bronchospasm. Rationale: A bronchospasm limits expiration; therefore, the capnograph would show a loss of plateau and a low ETCO2 level or "shark fin" appearance. A humped or camel configuration may indicate changes in the ET tube's position; the tube touching the carina would cause this waveform. If the tube became dislodged, the nurse would see a poor plateau or a flat waveform. A downward slope of the plateau indicates an inadequate seal around the ET tube.
