ABSTRACT
Aim:
The monitoring of oxygenation is essential for providing patient safety and optimal results. We aimed to determine brain oxygen saturation values in healthy, asphyctic and premature newborns and to compare cerebral oximeter and pulse oximeter values in the first 72 hours of life in neonatal intensive care units.
Methods:
This study was conducted at the neonatal intensive care unit (NICU) of Van Yüzüncü Yil University Research and Administration Hospital. Seventy-five neonatal infants were included in the study (28 asphyxia, 24 premature and 23 mature healthy infants for control group). All infants were studied within the first 72 hours of life. We used a Somanetics 5100C cerebral oximeter (INVOS cerebral/somatic oximeter, Troy, MI, USA). The oxygen saturation information was collected by a Nellcor N-560 pulse oximeter (Nellcor-Puriton Bennet Inc, Pleasanton, CA, USA).
Results:
In the asphyxia group, the cerebral oximeter average was 76.85 ± 14.1, the pulse oximeter average was 91.86 ± 5.9 and the heart rate average was 139.91 ± 22.3. Among the premature group, the cerebral oximeter average was 79.08 ± 9.04, the pulse oximeter average was 92.01 ± 5.3 and the heart rate average was 135.35 ± 17.03. In the control group, the cerebral oximeter average was 77.56 ± 7.6, the pulse oximeter average was 92.82 ± 3.8 and the heart rate average was 127.04 ± 19.7.
Conclusion:
Cerebral oximeter is a promising modality in bedside monitoring in neonatal intensive care units. It is complementary to pulse oximeter. It may be used routinely in neonatal intensive care units.
Keywords: Monitoring, newborn, neonatal intensive care unit
RESUMEN
Objetivo:
El monitoreo de la oxigenación es esencial para proporcionar seguridad y resultados óptimos al paciente. El objetivo de este trabajo fue determinar los valores de saturación de oxígeno cerebral en recién nacidos sanos, asfícticos, y prematuros, y comparar los valores del oxímetro cerebral y los valores del oxímetro de pulso en las primeras 72 horas de vida de los neonatos en las unidades de cuidados intensivos.
Métodos:
Este estudio fue realizado en la Unidad Neonatal de Cuidados Intensivos (UNCI) en el Hospital Universitario de Administración e Investigación Van Yüzüncü Yil. Setenta y cinco neonatos se incluyeron en el estudio (28 asfícticos, 24 prematuros, y 23 maduros sanos para el grupo control). Todos los recién nacidos fueron estudiados dentro de las primeras 72 horas de vida. Utilizamos un oxímetro cerebral Somanetics modelo Invos 5100C (oxímetro cerebral/somático INVOS, Troy, MI, USA). La información sobre la saturación de oxígeno fue recogida por un oxímetro de pulso Nellcor N-560 (Nellcor-Puriton Bennet Inc, Pleasanton, CA, USA).
Resultados:
En el grupo de asfixia, el promedio correspondiente al oxímetro cerebral fue ± 76.85 14.1, el promedio del oxímetro de pulso fue 91.86 ± 5.9, y el ritmo cardíaco promedio fue de 139.91 ± 22.3. En el grupo de prematuros, el oxímetro cerebral indicó un promedio de ± 79.08 9.04, el oxímetro de pulso señaló un promedio de 92.01 ± 5.3, y el promedio del ritmo cardíaco fue de ± 135.35 17.03. En el grupo control, el promedio del oxímetro cerebral fue 77.56 ± 7.6, el promedio del oxímetro de pulso fue 92.82 ± 3.8, y el ritmo cardíaco promedio fue de 127.04 ± 19.7.
Conclusión:
Oxímetro cerebral es una modalidad prometedora para el monitoreo de cabecera en las unidades de cuidados intensivos neonatales, y complementa la función del oxímetro de pulso. Puede utilizarse rutinariamente en las unidades de cuidados intensivos neonatales.
INTRODUCTION
The cerebral oximeter (CO) provides a direct method for measuring cerebral oxygen saturation. Pulse oximeter (PO) is a non-invasive, painless and reliable method for measuring oxygen saturation (SpO2) in blood (1). The PO value is affected by numerous factors. The area of measurement should be dry and clean with minimal movement. Dysrhythmia, shock, perfusion failure, abnormal pulsations, abnormal haemoglobin, use of vasoconstrictors, artefacts, dark skin, thick skin and excessively hairy skin may lead to incorrect results (1–6). Cerebral oximeter is a non-invasive technique based on near-infrared spectroscopy (NIRS), an optic technique similar to PO. Near-infrared spectroscopy uses infrared light and penetrates into live tissues and brain tissue. Near-infrared spectroscopy measures the infrared light absorbed through the tissue including pigments which allows continuous and non-invasive viewing of brain oxygenation (7). Pulsatile flow is not required for NIRS. Thus, it is useful in cardiopulmonary arrest and other non-pulsatile conditions (8).
We aimed to determine brain oxygen saturation values in healthy, asphyctic and premature newborns and to compare cerebral oximeter and pulse oximeter values in the first 72 hours of life in neonatal intensive care units.
SUBJECTS AND METHODS
This study was performed in the Neonatal Intensive Care Unit of Yüzüncü Yil University Faculty of Medicine Research and Practice Hospital between May 2008 and September 2009. The families consented to this study. Three families withdrew from the study and three patients were excluded because they did not satisfy the study criteria. Somanetics 5100C (INVOS cerebral/somatic oximeter, Troy, MI, USA) CO measure device was used in this study. Self-adhesive neonatal sensors were attached to the centre of the patients' foreheads. Data on SpO2 were collected by a Nellcor N-560 (Nellcor-Puriton Bennet Inc, Pleasanton, CA, USA) PO device. The probe of the device was placed onto the right wrist of the patients. Initial values of CO, PO and peak heart rate (PHR) were obtained and then every hour for 24 hours. A total of 25 values were recorded.
Seventy-five neonatal infants were included in the study (28 asphyxia, 24 premature and 23 mature healthy infants for control group). All infants were studied within the first 72 hours of life. The infants with respiratory distress syndrome, transient tachypnoea of the newborn, sepsis, septic shock, pneumonia, congenital infection, congenital heart disease, or congenital anomaly were excluded from the study. White blood cell count, haemoglobin, haematocrit, platelet count, creatinine kinase, creatinine kinase-MB, alanine transamin-ase, aspartate transaminase, lactate dehydrogenase, uric acid and C-reactive protein were analysed in serum. pH, partial pressure of carbon dioxide (pCO2), partial pressure of oxygen (pO2), bicarbonate (HCO3) and base deficit levels were analysed in blood gases.
The data were analysed by SPSS v 15.0 for Windows software. The analysis of variance (ANOVA) and Student's t-test were performed. A p-value < 0.05 was considered to indicate statistical significance. The study was approved by the Ethics Committee of the Faculty of Science, Yüzüncü Yil University.
RESULTS
All cases (n: 75) were included in the study in the initial first hour and then in the 72nd hour. Mean duration of inclusion was 30.6 (± 21.5) hours. Thirty patients were female (40%) and 45 patients were male (60%). The lowest infant weight was 1370 g, the highest was 4000 g, and the mean weight was 2622 (± 817) g. The youngest mother was 17 years and the oldest was 47 years. Mean age of mother was 29.4 (± 7.6) years. One patient was born at home (1.3%) and 74 were born at a hospital (98.7%). Twenty-six patients were delivered via vaginal delivery (34.7%) and 49 patients were delivered through Caesarean section (65.3%). The earliest born infant was 29 weeks of age; the latest born infant was 40 weeks old. Mean period of gestation was 36.13 (± 3.5) weeks. Demographic data of all patients are demonstrated in Table 1.
Table 1. Comparison of groups by their demographic characteristics.
| Parameters | Asphyxia group (n = 28) count (%) | Premature group (n = 24) count (%) | Control group (n = 23) count (%) | All groups (n = 75) count (%) | |
|---|---|---|---|---|---|
| Birth | |||||
| Home | 0 (0%) | 1 (4.2%) | 0 (0%) | 1 (1.3%) | |
| Hospital | 2 (100%) | 23 (95.8%) | 23 (100%) | 74 (98.7%) | |
| Delivery | |||||
| Vaginal | 12 (42.9%) | 5 (20.8%) | 9 (39.1%) | 26 (34.7%) | |
| Caesarean | 16 (57.1%) | 19 (79.2%) | 14 (60.9%) | 49 (65.3%) | |
| section | |||||
| Gender | |||||
| Female | 8 (28.6%) | 11 (45.8%) | 11 (47.8%) | 30 (40%) | |
| Male | 20 (71.4%) | 13 (54.2%) | 12 (52.2%) | 45 (60%) | |
| Mean study inclusion (hour) | 30.2 ±23.0 | 35.5 ±21.3 | 26.1 ±19.5 | 30.6 ±21.5 | |
| Mean weight (g) | 2847 ±818 | 1884 ±510 | 3117 ±488 | 2622 ±817 | |
| Mean mother's age (year) | 30.2 ±6.6 | 28.5 ±7.6 | 29.3 ±8.9 | 29.4 ±7.6 | |
| Mean pregnancy (week) | 37.0 ±3.8 | 32.7 ±2.0 | 38.5 ±0.5 | 36.1 ±3.5 | |
Patients were compared by mother's age, delivery week, Apgar score in the 1st minute, Apgar score in the 5th minute, body weight, white blood cell counts, haemoglobin levels, haematocrit levels, thrombocyte counts, uric acid, C-reactive protein, aspartate transaminase, alanine transaminase, lactate dehydrogenase, creatinine kinase, creatinine kinase-MB, pH, pCO2, pO2, HCO3 and base deficits. These conditions are shown in Table 2.
Table 2. Comparison of groups by their mean parameters.
| Parameters | Asphyxia group | Premature group | Control group |
|---|---|---|---|
| Mother's age (year) | 30.2 | 28.5 | 29.3 |
| Pregnancy (week) | 37.0a | 32.7c | 38.5b |
| Apgar score at 1st minute | 3.32a | 5.86 | 6.83 |
| Apgar score at 5th minute | 5.42 | 8.32c | 5.42b |
| Weight | 2847a | 1884 | 3117b |
| White blood cell count | 22594.64a | 13022.08 | 14303.04b |
| Haemoglobin level | 16.55 | 17.04 | 17.44 |
| Haematocrit level | 50.68 | 51.21 | 52.66 |
| Platelet count | 220071.43 | 211833.33 | 239347.83 |
| C-reactive protein | 6.47a | 3.00 | 3.00b |
| Uric acid | 8.665a | 5.891 | 5.091b |
| Aspartate transaminase | 186.64a | 42.75 | 60.83b |
| Alanine transaminase | 73.89a | 11.74 | 16.61b |
| Lactate dehydrogenase | 2684.89a | 986.38 | 982.74b |
| Creatinine kinase | 2622.68a | 273.29c | 514.61b |
| Creatinine kinase-MB | 623.82a | 68.04 | 64.52b |
| pH | 7.26a | 7.37 | 7.38b |
| pCO2 | 36.79a | 31.67 | 29.35b |
| pO2 | 73.36 | 66.08 | 72.91b |
| HCO3 | 16.55a | 18.33 | 16.54b |
| Base deficit | -10.11a | -5.13 | -6.17b |
A significant difference was noted when the asphyxia group and premature group were compared to each other (p < 0.05)
A significant difference was noted when the asphyxia group and control group were compared to
A significant difference was noted when the premature group and control group were compared to each other (p < 0.05)
pCO2: partial pressure of carbon dioxide, pO2: partial pressure of oxygen, HCO3: bicarbonate
In the asphyxia group, the mean value for CO was 76.85 ± 14.1, mean value for PO was 91.86 ± 5.9 and mean PHR was 139.91 ± 22.3. In the premature group, mean value for CO was 79.08 ± 9.04, mean value for PO was 92.01 ±5.3, and mean PHR was 135.35 ± 17.03. In the control group, mean value for CO was 77.56 ± 7.6, mean value for PO was 92.82 ± 3.8 and mean PHR was 127.04 ± 19.7.
In statistical analysis, PO values were significantly low and PHR values were significantly high in the asphyxia group compared to the control group. Cerebral oximeter values were slightly low in the asphyxia group and no significant differences were found (p > 0.05). The CO value was significantly different in the asphyxia and premature groups (p < 0.05). For PO values, no significant differences were recorded (p > 0.05) in the asphyxia and premature groups. The PHR value was significantly different in the asphyxia and premature groups (p < 0.05). As the result of correlation analysis: moderate correlation was determined between CO and PO, and this correlation was significant. A negative and poor correlation was found between CO and PHR. There was a non-significant relationship between PHR and PO.
DISCUSSION
Cerebral oximeter is a non-invasive optic technique based on NIRS which allows continuous and synchronous monitoring of the oxygen saturation of cerebral tissue (7, 9, 10). Cerebral oximeter is a promising modality in neonatal intensive care units (11).
Today, the central nervous system imaging techniques are quite advanced. These imaging techniques have advanced in identifying neurological, anatomical and structural anomalies. However, in the central nervous system functions, screenings are not at the desired level. In today, the standard of care monitoring is based on maintaining intraoperative and postoperative blood pressure to ensure proper cerebral perfusion and cerebral oxygenation. However, cerebral oxygenation may be inadequate even if proper blood pressure is sustained (12).
Cerebral oximeter measurement is the only non-invasive method for simple interventions in the continuous monitoring of cerebral blood oxygen saturation and for improving cerebral oxygen deficiencies. Clinical studies showed that CO usage improved results and decreased neurological complications and reduced hospital costs. Near-infrared spectroscopy is a promising technique as a clinical device for bedside measurements of cerebral blood flow and as a cerebral imaging approach revealing structure and function (13). Correlations were observed between NIRS and SpO2 during the graded hypoxia recorded in voluntary individuals (9). The first controlled study of CO was performed in 2006 by Rais-Bahrami et al (13). In this study, veno-venous extracorporeal membrane oxygenization was compared to cerebral venous oxygen saturation measured in neonatal infants. The CO value was found to be between 30% and 100% for neonatal infants in this system (13). According to observations, PO and CO values were correlated. One parameter increased or decreased as the other one increased or decreased.
A lot of CO devices have performed for normal oxygen saturation values. Weiss et al (14) using NIRO 300 (Hamamatsu Photonics), found a mean CO value of 60.5% ± 11.5%. Misra et al (15), using INVOS 3100, recorded a mean CO value of 67.2% ± 8.4%. Yoshitani et al (16), using INVOS 4100 and NIRO 300, found a mean CO value of 66% ± 8% and 66% ± 7%, respectively. In a study of 31 infants, Aldrich et al (17) detected the mean value of CO measured within 30 minutes after delivery as 22–73%. Schwartz et al (18) determined the mean value of CO in 18 healthy adults subjects as 68% ± 5%. On the other hand, Grubhofer et al (19) measured the mean CO values in the first three days of newborn premature infants as 54–65.7%, 61.9–82.3% and 67.8– 80.1%, respectively. Isobe et al (20) determined CO as 67– 74% when SpO2 was above 95%.
In our study, mean value for CO was 76.85 ± 14.1, mean value for PO was 91.86 ± 5.9, and mean PHR was 139.91 ± 22.3 in the asphyxia group. The mean value for CO was 79.08 ± 9.04, mean value for PO was 92.01 ± 5.3 and mean PHR was 135.35 ± 17.03 in the premature group. Mean value for CO was 77.56 ±7.6, mean value for PO was 92.82 ± 3.8 and mean PHR was 127.04 ± 19.7 in the control group. According to the literature, our values were slightly higher. This may be explained by the younger age of our patients which allowed for easier penetration of infrared light into the brain tissue due to the thin skin.
In our study, PO values were significantly low in the asphyxia group and PHR values were significantly high compared to the control group. However, CO values were slightly low in the asphyxia group and no significant differences were found (p > 0.05).
When the asphyxia and the control groups were compared, no significant difference was found between PHR, PO and CO. This might be because patients in the asphyxia group were connected to a mechanical ventilator or put on support oxygen.
There was moderate correlation between CO and PO. This correlation was significant. A negative and poor correlation was found between CO and PHR. A poor relationship existed between PHR and PO. This relationship was not significant.
In summary, CO seems to assist in restoring decrease in brain-oxygen flow. It may be helpful in the clinical management of asphyctic infants. Cerebral oximeter is a promising modality in the bedside monitoring in neonatal intensive care units. It is complementary to PO and may be used routinely in neonatal intensive care units.
REFERENCES
- 1.Popovich DM, Richiuso N, Danek G. Pediatric health care providers' knowledge of pulse oximetry. J Pediatr Nurs. 2004;30:14–20. [PubMed] [Google Scholar]
- 2.Barker SJ, Tremper KK, Hyatt J. Effects of methemoglobinemia on pulse oximetry and mixed venous oximetry. Anesthesiology. 1989;70:112–117. doi: 10.1097/00000542-198901000-00021. [DOI] [PubMed] [Google Scholar]
- 3.Hanning CD, Alexander-Williams JM. Pulse oximetry: a practical review. BMJ. 1995;311:367–370. doi: 10.1136/bmj.311.7001.367. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Ralston AC, Webb RK, Runciman WB. Potential errors in pulse oximetry. III: effects of interferences, dyes, dyshaemoglobins and other pigments. Anaesthesia. 1991;46:291–295. doi: 10.1111/j.1365-2044.1991.tb11501.x. [DOI] [PubMed] [Google Scholar]
- 5.Sendak MJ, Harris AP, Donham RT. Accuracy of pulse oximetry during arterial oxyhemoglobin desaturation in dogs. Anesthesiology. 1988;68:111–114. doi: 10.1097/00000542-198801000-00018. [DOI] [PubMed] [Google Scholar]
- 6.Salyer JW. Neonatal and pediatric pulse oximetry. Respir Care. 2003;48:386–396. [PubMed] [Google Scholar]
- 7.Owen-Reece H, Smith M, Elwell CE, Goldstone JC. Near infrared spectroscopy. Br J Anaesth. 1999;82:418–426. doi: 10.1093/bja/82.3.418. [DOI] [PubMed] [Google Scholar]
- 8.Tobias JD. Cerebral oximetry monitoring provides early warning of hypercyanotic spells in an infant with tetralogy of Fallot. J Intensive Care Med. 2007;22:118–120. doi: 10.1177/0885066606297966. [DOI] [PubMed] [Google Scholar]
- 9.Pollard V, Prough DS, DeMelo AE, Deyo DJ, Uchida T, Stoddart HF. Validation in volunteers of a near-infrared spectroscope for monitoring brain oxygenation in vivo. Anesth Analg. 1996;82:269–277. doi: 10.1097/00000539-199602000-00010. [DOI] [PubMed] [Google Scholar]
- 10.Cooper CE, Elwell CE, Meek JH, Matcher SJ, Wyatt JS, Cope M, et al. The noninvasive measurement of absolute cerebral deoxyhemoglobin concentration and mean optical path length in the neonatal brain by second derivative near infrared spectroscopy. Pediatr Res. 1996;39:32–38. doi: 10.1203/00006450-199601000-00005. [DOI] [PubMed] [Google Scholar]
- 11.Benni PB, Chen B, Dykes FD, Wagoner SF, Heard M, Tanner AJ, et al. Validation of the CAS neonatal NIRS system by monitoring vv-ECMO patients: preliminary results. Adv Exp Med Biol. 2005;566:195–201. doi: 10.1007/0-387-26206-7_27. [DOI] [PubMed] [Google Scholar]
- 12.Edmonds HL, Jr, Ganzel BL, Austin EH., 3rd Cerebral oximetry for cardiac and vascular surgery. Semin Cardiothorac Vasc Anesth. 2004;8:147–166. doi: 10.1177/108925320400800208. [DOI] [PubMed] [Google Scholar]
- 13.Rais-Bahrami K, Rivera O, Short BL. Validation of a noninvasive neonatal optical cerebral oximeter in veno-venous ECMO patients with a cephalad catheter. J Perinatol. 2006;26:628–635. doi: 10.1038/sj.jp.7211573. [DOI] [PubMed] [Google Scholar]
- 14.Weiss M, Dullenkopf A, Kolarova A, Chulz G, Frey B, Baenziger O. Near-infrared spectroscopic cerebral oxygenation reading in neonates and infants is associated with central venous oxygen saturation. Paediatr Anaesth. 2005;15:102–109. doi: 10.1111/j.1460-9592.2005.01404.x. [DOI] [PubMed] [Google Scholar]
- 15.Misra M, Stark J, Dujovny M, Widman R, Ausman JI. Transcranial cerebral oximetry in random normal subjects. Neurol Res. 1998;20:137–141. doi: 10.1080/01616412.1998.11740496. [DOI] [PubMed] [Google Scholar]
- 16.Yoshitani K, Kawaguchi M, Tatsumi K, Kitaguchi K, Furuya H. A comparison of the INVOS 4100 and the NIRO 300 near-infrared spectrophotometers. Anesth Analg. 2002;94:586–590. doi: 10.1097/00000539-200203000-00020. [DOI] [PubMed] [Google Scholar]
- 17.Aldrich CJ, D'Antona D, Wyatt JS, Spencer JA, Peebles DM, Reynolds EO. Fetal cerebral oxygenation measured by near-infrared spectroscopy shortly before birth and acid-base status at birth. Obstet Gynecol. 1994;84:861–866. [PubMed] [Google Scholar]
- 18.Schwarz G, Litscher G, Kleinert R, Jobstmann R. Cerebral oximetry in dead subjects. J Neurosurg Anesthesiol. 1996;8:189–193. doi: 10.1097/00008506-199607000-00001. [DOI] [PubMed] [Google Scholar]
- 19.Grubhofer G, Tonninger W, Keznickl P, Skyllouriotis P, Ehrlich M, Hiesmayr M, et al. A comparison of the monitors INVOS 3100 and NIRO 500 in detecting changes in cerebral oxygenation. Acta Anaesthesiol Scand. 1999;43:470–475. doi: 10.1034/j.1399-6576.1999.430417.x. [DOI] [PubMed] [Google Scholar]
- 20.Isobe K, Kusaka T, Fujikawa Y, Okubo K, Nagano K, Yasuda S, et al. Measurement of cerebral oxygenation in neonates after vaginal delivery and Caesarean section using full-spectrum near infrared spectroscopy. Comp Biochem Physiol A Mol Integr Physio. 2002;132:133–138. doi: 10.1016/s1095-6433(01)00539-6. [DOI] [PubMed] [Google Scholar]