Asphyxia and blood gases

[billyvega]

what about the parameter for diagnosis asphyxia in the newborn, the arterial blood gases mean as an important score

[Stefan Johansson]

Dear billyvega,

do you mean how base deficit could be used as a predictive factor of encephalopathy?

Could the two articles/abstracts below be of interest?

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Threshold of metabolic acidosis associated with neonatal encephalopathy in the term newborn.

Wayenberg JL.

J Matern Fetal Neonatal Med. 2005 Dec;18(6):381-5.

OBJECTIVE: To determine the threshold of metabolic acidosis associated with neonatal encephalopathy (NE) in the term newborn.

METHODS: Term patients were included on the basis of abnormal hemodynamic, respiratory or neurological signs still persisting 30 min after birth. Base deficit (BD30) was measured in arterial blood between the 30th and the 45th min of life and correlated with the occurrence of NE during the first days of life using receiver operating characteristics (ROC) methodology.

RESULTS: Moderate or severe NE occurred in 26% of patients whose BD30 was higher than 10 mmol/L and in 79% of patients whose BD30 was higher than 18 mmol/L. No infants developed moderate or severe NE when BD30 was less than 10 mmol/L. The apex of ROC curve related to moderate or severe NE corresponds to a BD30 of 14 mmol/L. At this threshold, the sensitivity of BD30 is 73.2% and the specificity 82%.

CONCLUSION: The threshold of metabolic acidosis that provides the best combination of sensitivity and specificity in relation to the occurrence of moderate or severe NE was a BD30 higher than 14 mmol/L. Significant birth asphyxia should be considered if BD30 exceeds 10 mmol/L.

Combination of early perinatal factors to identify near-term and term neonates for neuroprotection.

Talati AJ, Yang W, Yolton K, Korones SB, Bada HS.

J Perinatol. 2005 Apr;25(4):245-50.

OBJECTIVE: To determine early predictors of abnormal outcome at > or =24 months' age in neonates at risk for hypoxic-ischemic brain injury.

STUDY DESIGN: A prospective cohort study with developmental follow-up of > or =24 months. Infants were selected based on risk factors, and neurologic outcome was determined. Variables affecting the outcome were evaluated with univariate and multivariate methods, and a scoring system was devised to predict adverse outcome.

RESULTS: A total of 41 infants born > or =35 weeks' gestational age with possibility of hypoxic-ischemic insult were enrolled. In all, 39 (95%) had known outcomes, of whom 17 (48%) had an abnormal neurologic outcome, including five deaths. The variables within the first hour of life correlating with the adverse outcome were 1- and 5-minute Apgar scores, intubation in the delivery room and cord/initial base-deficit > or =20 mmol/l. A scoring system was derived based on significant variables, and a score > or =5 had a 90% positive predictive value for abnormal outcome. Seizures, multiorgan failure and abnormal imaging studies were also significantly associated with abnormal outcome.

CONCLUSIONS: The proposed scoring system, being highly predictive of outcome at 24 months' age, may be potentially useful in selecting subjects for preventive or therapeutic interventions to prevent or minimize neurologic morbidity due to hypoxic brain injury.

[Guest]

Does anyone have any experience with other asphyxia markers ?

[Guest sjbrott]

Is anyone trying hypothermia, systemic or cranial, to minimize the effects of HIE? Candidates for this form of therapy must first be placed on aEEG to determine if any brain activity is present. Sustained cranial or systemic hypothermia needs to be initiated by 6 hours from birth to be effective.

[Guest galaxy_7]

he asks on diagnosis, not prediction nor mangement .. i guess the american academy of gynacology and obstetrics in conjoint statment with the APP states a good parameter of diagnosing perinatal ischaemai/hypoxia

1) cord blood PH less than 7.

2) apgar score less than 3 for more than 5 mints

3) multiple organ involvement

4) focal neurological signs as coma convulsion

i guess you can further read this in the issue of clinics of north america pertinent to neonatology in 2004

[hehady]

Abnormalities in early aEEG (within 3 hours of birth) can be a useful adjunt to blood gas abnormalities (sepcifically a base deficit > 10 mEq/L) in umbilical or early arterial blood sample and clinical evidence (Apgar score at 5 minutes < 5; delayed first brith, antenatal evidence (Abnormalities in FHR tracing).

[Stefan Johansson]

Is anyone trying hypothermia, systemic or cranial, to minimize the effects of HIE? Candidates for this form of therapy must first be placed on aEEG to determine if any brain activity is present. Sustained cranial or systemic hypothermia needs to be initiated by 6 hours from birth to be effective.

Hypothermia is a hot issue right now, so I copied sjbrott's message to a separate thread.

Discuss hypothermia here : http://99nicu.org/forum/showthread.php?t=126

[Marta Muresan]

Does anyone have any experience with other asphyxia markers ?

Yes. Cerebral US is a good marker. Please read my artile about it.Sorry for the late response.

PREDICTIVE VALUE OF CRANIAL ULTRASOUND IN HIPOXIC ISCHEMIC NEONATAL ENCEPHALOPATY

Marta Muresan*,

*Clinica Obstetrica Ginecologie II, "Dominic Stanca" Cluj-Napoca- sectia Nou-Nascuti

Abstract: The relation of neonatal US abnormalities to neurologic outcome was examined in a prospectively followed cohort of 42 neonates with hipoxic-ischemic neonatal encephalopaty (HI-NE). The study group had consisted of 30 asphyxiated neonate with abnormal ultrasonograms and their neurological outcome was compared to the outcome of 12 asphyxiated infants without US abnormalities (control group). We used van Wezel Meijler`s score system to grade the intensity of parenchymal echogenicity. The results shown that the frequency of abnormal outcome in the study group (83%) was significantly different (for p<0,01) than that in patients with normal US scans (8%). US examination had a high sensitivity (94%), specificity (92%), 85% accuracy and 83% positive predictive value for neurologic outcome in infants with HI-NE. A high positive predicting value of bad prognosis had severe, generalized diffuse PHYE (sever brain edema) (90%), hyperechogenicity in BGTL, in the brainstem and in the subcortical region (100%). Less frequent abnormal outcome was predicted by parenchymal echodensities (76%) than by cystic lesions (86%), and by ventricle size (70%) compared with parenchymal abnormalities (79%), differences were significant (p<0,05). We describe a new pattern of hypoxic-ischemic US abnormality, periventricular pseudocyst, which appears in severe asphyxiated term infants, in the area of previous hyperechogenicity of external angle of lateral ventricles and had a poor outcome. Highest degree of echogenicity of parenchyma carried the highest predictive value for neurologic impairment (gr.2 intensity PHYE 90% versus 64% gr.2 PHYE). We conclude that US could identify the risk of abnormal neurologic development in infants with HI-NE, with high sensitivity and specificity. Grading of parenchymal hyperechogenicity could serve as a prognostic criterion in HI-NE as well as the location and extension of echodensities.