Table 2.
Studies in infants with birth asphyxia documenting brain pHi measured by 31P MRS (based on [4, 5, 33, 36, 38, 151, 154, 157])
| Reference | n | GA at birth (weeks) | Age when studies | Mean brain pHi | Localization |
|---|---|---|---|---|---|
| Cady et al. [157] | 7 (3 birth asphyxia) | 33–40 | 42 h–26 days | 7.2 (SD 0.1)a | Surface coil |
| One infant studies on 5 occasions (on day 26: brain pHi = 7.4) | |||||
| Hope et al. 1984 [36] | 10 | 38–41 | 8 h–27 days (obtained in 3–6 times in each infant) | 7.17 ± 0.1 at time of lowest PCr/Pi (mean age 113 h: 16 h–9 days) | Surface coil |
| Hamilton et al. [151] | 27 Echodensities seen on USS (13 birth asphyxia) | Median 40 (27–42) | Median 3 days (8 h–23 days) | “Tended to be raised.” Values from 19 of the infants were above the regression line for normal infants; 6 were above the 95 % CI | Surface coil |
| Laptook et al. [154] | 1 | 36 | 1.5, 8, 15 days, 9 months | 7.3–7.4 | Surface coil |
| 5 | 38 ± 2 | Within first 2 weeks after birth | 7.14 (±0.12) Significantly different from the normal infants when other 31P metabolites showed no difference | ||
| Azzopardi et al. [33] | 61 (all infants) | 27–42 | 3 days (0–23) | 7.14 ± 0.27 (n = 61) | Surface coil |
| 40 infants with asphyxia | 40 (31–42) | 3 days (1–10) | 7.16 ± 0.19 (n = 36) | ||
| Martin et al. [38] | 23 | Median 40 (36.9–41.9) | Median 3 days (NNS 1—severe) | 7.21 (±0.16) | Volume localized (ISIS) |
| Median 5.5 days (NNS 2—moderate) | 7.09 (±0.04) | ||||
| Median 3 days (NNS 3—mild) | 7.10 (±0.08) | ||||
| Robertson et al. [4] | 43 | Median 39.5 (36–42) | 77 examinations: 25 within 2 weeks age 16 between 2 and 4 weeks | At time of lowest PCr/Pi (within first 2 weeks of age) | Volume localized (CSI) |
| 25 between 4 and 30 weeks | 7.23 (±0.07)—abnormal outcome group | ||||
| 11 when >30 weeks old | 7.08 (±0.04)—normal outcome group | ||||
| Robertson et al. [5] | 78 | 39.5 (SD 1.6) (36–42) | 151 examinations within the first year after birth. 50 infants studies within 2 weeks of age | At time of lowest PCr/Pi (within first 2 weeks of age) | Volume localized (ISIS) |
| 35 (+ 43 presented above) | 7.28 (±0.15)—23 infants with severe outcome or died | ||||
| 7.11 (±0.09)—normal outcome group |
NNS neonatal score, NNS1 severe NE, NNS 2 moderate NE, NNS 3 mild NE, GA gestational age, PNA postnatal age
aThe pHi was taken from a heterogeneous group of infants including infants with congenital muscular dystrophy and with meningitis. The author noted there was no evidence of intracellular acidosis in infants with birth asphyxia and stated that the pHi was similar in infants with birth asphyxia to those without. On close examination, however, infants with birth asphyxia tended to have a more alkaline pHi