C A S E S T U D Y The Use of Capnography and NPPV in Hypercapnic Respiratory Failure Jhaymie L. Cappiello, RRT RCP Duke University Medical Center, Durham, NC
A 73-year-old male with a complex history of COPD, hypertension and previous myocardial infarctions presented to the emergency
department in severe respiratory distress. The patient was placed on Noninvasive Positive Pressure Ventilation (NPPV) using a
Respironics BiPAP® Vision® Ventilatory Support System. To evaluate the adequacy of NPPV, End-Tidal C02 (ETC02) was continuously monitored via nasal cannula using the Respironics CO2SMO® Capnograph with the CAPNOSTAT® CO2 sensor in the sidestream mode. CLINICAL COURSE
The patient continued to improve. At 1135 with an RR of 28 and
an ETCO2 of 38 mmHg, the patient was removed from NPPV and
The patient presented to the emergency department at 0955 in
placed on a mask with 40% FIO2 (Figure 3).
severe respiratory distress. Although the patient was unable to
speak more than two words, he was alert and cooperative. The
patient received nebulized albuterol and atrovent with oxygen.
Initial vital signs at 1000 were: RR 36, HR 101, BP 168/73,
O2 saturation 95% on 8 L/min O2, and an End-Tidal CO2 (ETCO2)of 26 mmHg (Figure 1). The capnogram was indicative of alveolar
hypoventilation and an incomplete expiratory phase.
Patient monitoring with capnography was continued. Changes in
both the waveform and ETCO2 level were assessed. At 1205, the
vital signs were: RR 24, HR 96, BP 131/52, 95% saturation on
40% FIO2, and ETCO2 36 mmHg with no changes in waveform.
The patient was placed on 4 L/min of oxygen via nasal cannula and
90 minutes later was transferred to a general care monitored room.
DISCUSSION
of 87 mmHg. At 1005 the patient was placed on NPPV with an
Capnography depicts ETCO2 trends and enables alveolar
IPAP of 10 cm H2O, EPAP of 5 cm H2O, and a FIO2 of 0.40.
assessment in real time. In this case, the baseline ETCO2 -
At 1020, the respiratory rate had decreased to 30 and the ETCO2
PaCO2 was large, which is often indicative of a COPD patient.
had increased to 45 mmHg. The capnogram changed, revealing
With capnography, alveolar ventilation changes can be detected
a longer expiratory limb (Figure 2).
without the need for serial arterial blood gas draws. Additionally,
capnographic waveform analysis enables an accurate assessment
of alveolar progression. The combination of capnography with
NPPV can permit the rapid stabilization of the patient’s
respiratory condition and shorten the time needed for
The respiratory rate had further decreased to 28 by 1035 with an
ETCO2 of 43 mmHg and a full expiratory waveform. At 1105 the
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vital signs were: RR 22, HR 102, BP 121/88, 97% O
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on 40% O2, NPPV 10/5, and ETCO2 38 mmHg. At this point, thepatient was able to speak in complete sentences. An ABG revealed
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a pH of 7.34, a PaCO2 of 52 mmHg, and a PaO2 of 80 mmHg.
Fill the gaps using these key words and phrases from the text: worth 1. A ____________ drink has gas bubbles in it. Another word for this is 2. The ____________ is the place where you can buy and sell shares in 3. A ____________ is 3 months of the year. January to March is the first 4. A ____________ is a small amount of food you eat between meals. 5. If you say how much some