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Pediatrics International (2015) 57, 186–188
doi: 10.1111/ped.12553
Brief Report
Expiratory CO2 as the first sign of successful ventilation during neonatal resuscitation Hiroshi Mizumoto, Yoichi Iki, Sumie Yamashita and Daisuke Hata Department of Pediatrics, Tazuke Kofukai, Medical Research Institute, Kitano Hospital, Osaka, Japan Abstract
Three-lead electrocardiography and expired CO2 monitoring were used during positive pressure ventilation of seven non-intubated newborns (gestational age, 31–37 weeks; birthweight, 1503–2885 g). In all cases, adequate CO2 (>15 mmHg) was detected prior to the achievement of stable heart rate (>100 beats/min). The delay between detection of adequate CO2 and improvement of bradycardia ranged from 8 to 73 s (median, 15 s). Inadequate expired CO2 during positive pressure ventilation indicates airway obstruction or poor aeration of the newborn lungs. Thus, positive expiratory CO2 can be the first recognizable sign of successful ventilation during neonatal resuscitation.
Key words electrocardiogram, expiratory carbon dioxide, neonatal resuscitation, positive pressure ventilation.
Adequate ventilation of the lungs is critical for successful cardiopulmonary resuscitation of asphyxiated newborns. Effective positive pressure ventilation (PPV) improves vital signs and chest movement during inspiration, but it is often difficult to visualize chest rise immediately after birth.1 Therefore, clinical assessment of effective PPV can be challenging if vital signs remain unimproved. We previously reported that electrocardiography (ECG) is superior to pulse oximetry (PO) in the determination of heart rate.2 In addition, colorimetric CO2 monitoring can assess airway patency during PPV.3 To our knowledge, only a few studies have evaluated the relationship between positive expiratory CO2 (ECO2) and improvement in heart rate during neonatal resuscitation.4 Since 2011, we have used ECG, PO, and ECO2 monitor during resuscitation of high-risk newborns, and hypothesized that positive ECO2 is the first recognizable sign of successful ventilation. The aim of this study was to verify this hypothesis.
TL-273T; Nihon Kohden, Tokyo, Japan) to the right palm of the newborn, while another member attached three ECG leads (model Vitrode V; Nihon Kohden) to the chest. An ECO2 monitor (model TG-920P; Nihon Kohden) was applied between the mask and the flow-inflating resuscitation bag. The three monitors were connected to a multi-parameter instrument (Cardiolife model TEC-8300; Nihon Kohden). Resuscitation was performed according to the recently published guidelines.5 Data were recorded for at least 3 min. The three monitors continuously collected tracings, and data were analyzed after resuscitation (Fig. 1). Interventions were verbally announced and recorded. ECO2 >15 mmHg was regarded as adequate because domestically available colorimetric ECO2 detectors (Mini StatCO2, MPI, Tokyo, Japan; and PediCap, Covidien, Tokyo, Japan) show distinguishable color changes in response to this level.
Results Methods This study was performed at Kitano Hospital, between February 2013 and January 2014 and was approved by the Ethics Committee of Kitano Hospital. We obtained parental consent for data publication after birth. At least three individuals (pediatricians and nurses) were present at each delivery with high risk of neonatal apnea. These factors included preterm delivery, low estimated birthweight, non-reassuring fetal heart rate, and meconium-stained amniotic fluid. Immediately after birth, one member applied a PO (model
Correspondence: Hiroshi Mizumoto, MD, 2-4-20 Ohgimachi, Kita-ku, Osaka 530-8480, Japan. Email: [email protected] Received 27 August 2014; revised 24 October 2014; accepted 26 November 2014.
© 2015 Japan Pediatric Society
The PPV was performed in seven of 15 cases, which were reviewed in this study (Table 1, Fig. 2). Gestational age and birthweight ranged from 31 to 37 weeks (median, 36 weeks) and 1503 to 2885 g (median, 2316 g), respectively. All newborns had apnea and bradycardia (heart rate, 100 beats/min. The delay between the detection of adequate ECO2 and stable heart rate (>100 beats/min) was 8–73 s
Expiratory CO2 during PPV
187
Fig. 1 Monitor tracing of patient 7 between 130 and 210 s after birth. ECG, electrocardiography; HR, heart rate; PO, pulse oximetry (average for the subsequent 10 s); PPV, positive pressure ventilation. ○, Expiratory carbon dioxide (ECO2) >15 mmHg continuously detected for 10 s. - -, reliable wave not detected.
(median, 15 s). In patient 3, heart rate increased to >100 beats/ min only transiently before adequate ECO2 was detected continuously.
Discussion In the present study all seven newborns had adequate ECO2 prior to the achievement of stable heart rate (>100 beats/min); thus positive ECO2 can be the first sign of successful ventilation during neonatal resuscitation. Capnography is the most reliable method to assess the insertion of endotracheal tube after intubation and during patient transport. Leone et al. noted the usefulness of colorimetric CO2 detector during PPV as an indicator of patent airway in premature infants before endotracheal intubation.3 Furthermore, Finer et al. reported that CO2 colorimetry can detect airway obstruction during PPV in infants immediately after birth.6 Recently, Hooper et al. reported their animal experiment suggesting that initial low ECO2 is more likely to reflect poor lung aeration rather than over-ventilation during the immediate newborn period.4 They also showed that ECO2 increased above 10 mmHg approximately 28 s before heart rate increased above 100 beats/min in 10 preterm infants.
In the present study, we used capnography with waveform recordings, which may be more objective and reproducible than ECO2 colorimetry. In addition, we simultaneously recorded heart rate continuously on ECG, which clarified the relationship between ECO2 detection and the improvement of bradycardia. It seemed that in some cases (patients 2 and 5), the partial improvement of heart rate within 15 mmHg to bradycardia† PPV ECO2>15 mmHg HR > 100 PPV to recognized (s) started detected (s) HR >100 ECO2>15 mmHg (s) beats/min beats/min (s) (s) detected (s) 20 28 30 75 80 96 93
23 32 35 77 83 123 128
26 58 134 88 95 145 175
3 26 99 11 12 22 47
40 68 156 132 103 218 190
14 10 22 44 8 73 15
†HR
Pediatrics International (2015) 57, 186–188
doi: 10.1111/ped.12553
Brief Report
Expiratory CO2 as the first sign of successful ventilation during neonatal resuscitation Hiroshi Mizumoto, Yoichi Iki, Sumie Yamashita and Daisuke Hata Department of Pediatrics, Tazuke Kofukai, Medical Research Institute, Kitano Hospital, Osaka, Japan Abstract
Three-lead electrocardiography and expired CO2 monitoring were used during positive pressure ventilation of seven non-intubated newborns (gestational age, 31–37 weeks; birthweight, 1503–2885 g). In all cases, adequate CO2 (>15 mmHg) was detected prior to the achievement of stable heart rate (>100 beats/min). The delay between detection of adequate CO2 and improvement of bradycardia ranged from 8 to 73 s (median, 15 s). Inadequate expired CO2 during positive pressure ventilation indicates airway obstruction or poor aeration of the newborn lungs. Thus, positive expiratory CO2 can be the first recognizable sign of successful ventilation during neonatal resuscitation.
Key words electrocardiogram, expiratory carbon dioxide, neonatal resuscitation, positive pressure ventilation.
Adequate ventilation of the lungs is critical for successful cardiopulmonary resuscitation of asphyxiated newborns. Effective positive pressure ventilation (PPV) improves vital signs and chest movement during inspiration, but it is often difficult to visualize chest rise immediately after birth.1 Therefore, clinical assessment of effective PPV can be challenging if vital signs remain unimproved. We previously reported that electrocardiography (ECG) is superior to pulse oximetry (PO) in the determination of heart rate.2 In addition, colorimetric CO2 monitoring can assess airway patency during PPV.3 To our knowledge, only a few studies have evaluated the relationship between positive expiratory CO2 (ECO2) and improvement in heart rate during neonatal resuscitation.4 Since 2011, we have used ECG, PO, and ECO2 monitor during resuscitation of high-risk newborns, and hypothesized that positive ECO2 is the first recognizable sign of successful ventilation. The aim of this study was to verify this hypothesis.
TL-273T; Nihon Kohden, Tokyo, Japan) to the right palm of the newborn, while another member attached three ECG leads (model Vitrode V; Nihon Kohden) to the chest. An ECO2 monitor (model TG-920P; Nihon Kohden) was applied between the mask and the flow-inflating resuscitation bag. The three monitors were connected to a multi-parameter instrument (Cardiolife model TEC-8300; Nihon Kohden). Resuscitation was performed according to the recently published guidelines.5 Data were recorded for at least 3 min. The three monitors continuously collected tracings, and data were analyzed after resuscitation (Fig. 1). Interventions were verbally announced and recorded. ECO2 >15 mmHg was regarded as adequate because domestically available colorimetric ECO2 detectors (Mini StatCO2, MPI, Tokyo, Japan; and PediCap, Covidien, Tokyo, Japan) show distinguishable color changes in response to this level.
Results Methods This study was performed at Kitano Hospital, between February 2013 and January 2014 and was approved by the Ethics Committee of Kitano Hospital. We obtained parental consent for data publication after birth. At least three individuals (pediatricians and nurses) were present at each delivery with high risk of neonatal apnea. These factors included preterm delivery, low estimated birthweight, non-reassuring fetal heart rate, and meconium-stained amniotic fluid. Immediately after birth, one member applied a PO (model
Correspondence: Hiroshi Mizumoto, MD, 2-4-20 Ohgimachi, Kita-ku, Osaka 530-8480, Japan. Email: [email protected] Received 27 August 2014; revised 24 October 2014; accepted 26 November 2014.
© 2015 Japan Pediatric Society
The PPV was performed in seven of 15 cases, which were reviewed in this study (Table 1, Fig. 2). Gestational age and birthweight ranged from 31 to 37 weeks (median, 36 weeks) and 1503 to 2885 g (median, 2316 g), respectively. All newborns had apnea and bradycardia (heart rate, 100 beats/min. The delay between the detection of adequate ECO2 and stable heart rate (>100 beats/min) was 8–73 s
Expiratory CO2 during PPV
187
Fig. 1 Monitor tracing of patient 7 between 130 and 210 s after birth. ECG, electrocardiography; HR, heart rate; PO, pulse oximetry (average for the subsequent 10 s); PPV, positive pressure ventilation. ○, Expiratory carbon dioxide (ECO2) >15 mmHg continuously detected for 10 s. - -, reliable wave not detected.
(median, 15 s). In patient 3, heart rate increased to >100 beats/ min only transiently before adequate ECO2 was detected continuously.
Discussion In the present study all seven newborns had adequate ECO2 prior to the achievement of stable heart rate (>100 beats/min); thus positive ECO2 can be the first sign of successful ventilation during neonatal resuscitation. Capnography is the most reliable method to assess the insertion of endotracheal tube after intubation and during patient transport. Leone et al. noted the usefulness of colorimetric CO2 detector during PPV as an indicator of patent airway in premature infants before endotracheal intubation.3 Furthermore, Finer et al. reported that CO2 colorimetry can detect airway obstruction during PPV in infants immediately after birth.6 Recently, Hooper et al. reported their animal experiment suggesting that initial low ECO2 is more likely to reflect poor lung aeration rather than over-ventilation during the immediate newborn period.4 They also showed that ECO2 increased above 10 mmHg approximately 28 s before heart rate increased above 100 beats/min in 10 preterm infants.
In the present study, we used capnography with waveform recordings, which may be more objective and reproducible than ECO2 colorimetry. In addition, we simultaneously recorded heart rate continuously on ECG, which clarified the relationship between ECO2 detection and the improvement of bradycardia. It seemed that in some cases (patients 2 and 5), the partial improvement of heart rate within 15 mmHg to bradycardia† PPV ECO2>15 mmHg HR > 100 PPV to recognized (s) started detected (s) HR >100 ECO2>15 mmHg (s) beats/min beats/min (s) (s) detected (s) 20 28 30 75 80 96 93
23 32 35 77 83 123 128
26 58 134 88 95 145 175
3 26 99 11 12 22 47
40 68 156 132 103 218 190
14 10 22 44 8 73 15
†HR
