Ultrasound Evaluation of Gastric Emptying Time in Healthy Term Neonates after Formula Feeding.

BACKGROUND: The current American Society of Anesthesiologists fasting guideline for formula-fed infants in the periprocedural setting is 6 h. Prolonged fasting in very young infants is associated with an increased risk for hypoglycemia and dehydration as well as patient discomfort and patient/parental dissatisfaction. This study aimed to determine the time to gastric emptying in healthy neonates after formula feeding by serially evaluating the gastric antrum with ultrasound. The authors hypothesized that gastric emptying times in formula-fed neonates are significantly shorter than the current 6 h fasting recommendation. METHODS: After institutional review board approval and written informed parental consent, ultrasound examination was performed in healthy full-term neonates before and after formula feeding at 15-min intervals until return to baseline. Ultrasound images of the gastric antrum were measured to obtain cross-sectional areas, which were then used to estimate gastric antral volumes. RESULTS: Forty-six of 48 recruited neonates were included in the final analysis. Gastric emptying times ranged from 45 to 150 min and averaged 92.9 min (95% CI, 80.2 to 105.7 min; 99% CI, 76.0 to 109.8 min) in the overall study group. No significant differences were found in times to gastric emptying between male and female neonates (male: mean, 93.3 [95% CI, 82.4 to 104.2 min]; female: mean, 92.6 [95% CI, 82.0 to 103.2 min]; P = 0.930) or those delivered by vaginal versus cesarean routes (vaginal: mean, 93.9 [95% CI, 81.7 to 106.1 min]; cesarean: mean, 92.2 [95% CI, 82.5 to 101.9 min]; P = 0.819). CONCLUSIONS: These results demonstrate that gastric emptying times are substantially less than the current fasting guideline of 6 h for formula-fed, healthy term neonates.

Aquaporin-4 gene variant independently associated with oedema after intracerebral haemorrhage.

INTRODUCTION: Aquaporin-4 (AQP4) is the prominent water-channel protein in the brain playing a critical role in controlling cell water content. After intracerebral haemorrhage (ICH), perihematomal oedema (PHE) formation leads to a rapid increase in intracranial pressure (ICP) after the initial bleed. We sought to investigate the effect of a common genomic variant in the AQP4 gene on PHE formation after ICH. METHODS: We reviewed the literature and identified a candidate polymorphism in AQP4 genes previously reported in Genome Wide Association Studies (GWAS). Between February 2009 and March 2011, 128 patients consented to genetic testing and were genotyped for single nucleotide polymorphism (SNP) on the AQP4 gene. Genomic DNA was extracted from buccal swabs using MasterAmp extraction kits (Epicentre, Madison, WI, USA). DNA extracted from buffy coats of whole blood samples was amplified via PCR. Linear regression with log-transformed ICH + PHE volume as the response variable was used to determine the association of SNP controlled for admission variables age, GCS, infratentorial location, hypertension, systolic blood pressure (SBP), blood urea nitrogen (BUN), glucose and alkaline phosphatase. RESULTS: Nine of 128 patients had the minor allele for SNP rs1058427. Presence of the minor allele was significant in the model (P = 0.021), and associated with an increase of 88% in ICH + PHE volume (ß = 0.632, exp(ß) = 1.88) after controlling for admission variables. The only other significant variables included in the model was GCS (P < 0.001). CONCLUSION: The establishment of an independent association between rs1054827 and ICH + PHE volume provides evidence implicating the AQP4 gene in haematoma and oedema formation after ICH. Further investigation is needed to characterise this link.

Volume-dependent effect of perihaematomal oedema on outcome for spontaneous intracerebral haemorrhages.

INTRODUCTION: It is still unknown whether subsequent perihaematomal oedema (PHE) formation further increases the odds of an unfavourable outcome. METHODS: Demographic, clinical, radiographic and outcome data were prospectively collected in a single large academic centre. A multiple logistic regression model was then developed to determine the effect of admission oedema volume on outcome. RESULTS: 133 patients were analysed in this study. While there was no significant association between relative PHE volume and discharge outcome (p=0.713), a strong relationship was observed between absolute PHE volume and discharge outcome (p=0.009). In a multivariate model incorporating known predictors of outcome, as well as other factors found to be significant in our univariate analysis, absolute PHE volume remained a significant predictor of poor outcome only in patients with intracerebral haemorrhage (ICH) volumes ≤30 cm(3) (OR 1.123, 95% CI 1.021 to 1.273, p=0.034). An increase in absolute PHE volume of 10 cm(3) in these patients was found to increase the odds of poor outcome on discharge by a factor of 3.19. CONCLUSIONS: Our findings suggest that the effect of absolute PHE volume on functional outcome following ICH is dependent on haematoma size, with only patients with smaller haemorrhages exhibiting poorer outcome with worse PHE. Further studies are needed to define the precise role of PHE in driving outcome following ICH.