Accuracy of a New Low-flow Sidestream Capnography Technology in Newborns: A Pilot Study

Division of Newborn Medicine, Children's Hospital and Harvard Medical School, Boston, MA, USA.
Journal of Perinatology (Impact Factor: 2.07). 04/2002; 22(3):219-25. DOI: 10.1038/
Source: PubMed


To evaluate the accuracy of a new low-flow sidestream capnography technology and analyze components of the capnogram in mechanically ventilated newborns with and without pulmonary disease.
Twenty patients were prospectively identified. Eligible infants were mechanically ventilated and had an indwelling arterial catheter. Two groups were identified: newborns who were receiving mechanical ventilation for pulmonary diseases, and newborns who were receiving postoperative mechanical ventilation for nonpulmonary conditions. End-tidal CO(2) (PetCO(2)) was measured for 1-minute pre- and post-arterial blood sampling, and PetCO(2) and PaCO(2) were compared for each patient. Eight quantitative waveform parameters were also measured on all patients.
Newborns in the pulmonary group (n=13) (persistent pulmonary hypertension of the newborn/meconium aspiration syndrome, respiratory distress syndrome, pneumonia) and newborns in the control group (n=7) were matched for birth weight, gestational age, and postnatal age. PetCO(2)-PaCO2 Gradient values were higher in the pulmonary group (7.4+/-3.3 mm Hg) than controls (3.4+/-2.4 mm Hg). Four waveform parameters (ascending slope, alveolar angle, alpha angle, descending angle) were identified, which independently differentiated patients with pulmonary disease from controls.
Low-flow capnography with Microstream technology accurately measured alveolar CO(2) in newborns without pulmonary disease, as demonstrated by normal PetCO(2)-PaCO(2) gradients. The measured PetCO(2)-PaCO(2) gradient, as expected, was significantly higher in newborns with pulmonary disease. We also identified four quantitative waveform parameters that may be useful in differentiating between mechanically ventilated newborn patients with and without lung disease.

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Available from: David Zurakowski, Dec 13, 2013
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    • "Because of these prior studies most physicians agree that in the clinical setting of respiratory distress, EtCO2 monitoring is mostly useful in following the trend in ventilatory status and not as a specific correlate to blood gas pCO2.[23,28] However, knowing EtCO2 can serve as a direct corollary to blood gas pCO2 in patients without pulmonary disease[22,25,29], it raises the question of a possible threshold of pulmonary disease that until reached EtCO2 remains an accurate tool to assess blood gas pCO2. "
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    ABSTRACT: To investigate the correlation and level of agreement between end-tidal carbon dioxide (EtCO2) and blood gas pCO2 in non-intubated children with moderate to severe respiratory distress. Retrospective study of patients admitted to an intermediate care unit (InCU) at a tertiary care center over a 20-month period with moderate to severe respiratory distress secondary to asthma, bronchiolitis, or pneumonia. Patients with venous pCO2 (vpCO2) and EtCO2 measurements within 10 minutes of each other were eligible for inclusion. Patients with cardiac disease, chronic pulmonary disease, poor tissue perfusion, or metabolic abnormalities were excluded. Eighty EtCO2-vpCO2 paired values were available from 62 patients. The mean +/- SD for EtCO2 and vpCO2 was 35.7 +/- 10.1 mmHg and 39.4 +/- 10.9 mmHg respectively. EtCO2 and vpCO2 values were highly correlated (r = 0.90, p < 0.0001). The correlations for asthma, bronchiolitis and pneumonia were 0.74 (p < 0.0001), 0.83 (p = 0.0002) and 0.98 (p < 0.0001) respectively. The mean bias +/- SD between EtCO2 and vpCO2 was -3.68 +/- 4.70 mmHg. The 95% level of agreement ranged from -12.88 to +5.53 mmHg. EtCO2 was found to be more accurate when vpCO2 was 35 mmHg or lower. EtCO2 is correlated highly with vpCO2 in non-intubated pediatric patients with moderate to severe respiratory distress across respiratory illnesses. Although the level of agreement between the two methods precludes the overall replacement of blood gas evaluation, EtCO2 monitoring remains a useful, continuous, non-invasive measure in the management of non-intubated children with moderate to severe respiratory distress.
    BMC Pediatrics 02/2009; 9(1):20. DOI:10.1186/1471-2431-9-20 · 1.93 Impact Factor
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    • "In order to record and analyze instantaneous CO2 digitized waveforms, we chose the commercially available Oridion Microcap® CO2 portable bedside capnograph (Oridion Systems Ltd, Microcap®, model #CS-04178) [27]. It uses Microstream® Technology with low-flow, sidestream aspiration vs. traditional high-flow or mainstream monitors [28,29]. This monitor has a low sampling rate of 50 ml/min and an accuracy of EtCO2 readings of ± 2 mmHg in the range of 0–38 mmHg and ± 5% of the reading in the range of 39–99 mmHg, when steady state is reached. "
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    ABSTRACT: The objective was to determine the repeatability and stability of capnography interfaced with human exposure facility. Capnographic wave signals were obtained from five healthy volunteers exposed to particle-free, filtered air during two consecutive 5 min intervals, 10 min apart, within the open and then the sealed and operational human exposure facility (HEF). Using a customized setup comprised of the Oridion Microcap portable capnograph, DA converter and AD card, the signal was acquired and saved as an ASCII file for subsequent processing. The minute ventilation (VE), respiratory rate (RR) and expiratory tidal volume (VTE) were recorded before and after capnographic recording and then averaged. Each capnographic tracing was analyzed for acceptable waves. From each recorded interval, 8 to 19 acceptable waves were selected and measured. The following wave parameters were obtained: total length and length of phase II and III, slope of phase II and III, area under the curve and area under phase III. In addition, we recorded signal measures including the mean, standard deviation, mode, minimum, maximum--which equals end-tidal CO2 (EtCO2), zero-corrected maximum and true RMS. Statistical analysis using a paired t-test for means showed no statistically significant changes of any wave parameters and wave signal measures, corrected for RR and VTE, comparing the measures when the HEF was open vs. sealed and operational. The coefficients of variation of the zero-corrected and uncorrected EtCO2, phase II absolute difference, signal mean, standard deviation and RMS were less than 10% despite a sub-atmospheric barometric pressure, and slightly higher temperature and relative humidity within the HEF when operational. We showed that a customized setup for the acquisition and processing of the capnographic wave signal, interfaced with HEF was stable and repeatable. Thus, we expect that analysis of capnographic waves in controlled human air pollution exposure studies is a feasible tool for characterization of cardio-pulmonary effects of such exposures.
    BioMedical Engineering OnLine 02/2006; 5(1):54. DOI:10.1186/1475-925X-5-54 · 1.43 Impact Factor
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    ABSTRACT: Solunumsal komplikasyonlar anestezi komplikasyonlar›n›n önemli bölümünü oluflturur. Anestezi ve derlenme sürecinde ilk amac›m›z hastay› hipoksiden korumakt›r. Solunumsal kaynakl› anestezi kazalar›n›n % 85'inin ölümle ya da geri dönüflümü olmayan serebral lez- yonlarla seyrettii 1992'de aç›klanm›flt›r (1) . Puls oksimetre mükemmel bir hipoksi monitörü olmas›na ramen etyolojiyi tan›mlamayabilir. Kapnogram ise hipoksi ile sonuçlanabilecek durumlar› tan›mlayabilir. Puls oksimetre ve kapnograf›n birlikte kullan›lmas› anesteziye bal› komplikasyonlar›n % 93'den korumada yeterlidir. 1928'de Aiken ve Clark Kenedy volümetrik kapnografiyi literatürde ilk tan›mlayan kiflilerdir. Fowler 1948'de "tek solunumda nitrojen erisi"ni tan›mlam›flt›r. 1950'li y›llarda "infrared CO 2 meter" terimi kullan›lmaya bafllanm›fl ve yine bu y›llarda ilk kez Elam ve ark. insanda solu- numun ak›m profillerini ve kapnografiyi kaydetmifllerdir. 1957'de Smaulhout, Hollanda'da askeri hastanede çal›fl›rken kapnograf kullanarak 6000 hastan›n trasesinden elde ettii verile- ri 1967'de yay›nlam›flt›r. 1978'de Hollanda anestezi s›ras›nda standart monitorizasyon olarak kapnografiyi uygulayan ilk ülke olmufltur. 1986 ve daha sonra 1998'de yay›nlanan ASA'n›n temel monitorizasyon standartlar›nda solunum sistemi monitorizasyonunda kapnograf zorunlu hale getirilmifltir (2) .
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