Norepinephrine or phenylephrine for the prevention of post-spinal hypotension after caesarean section: A double-blinded, randomized, controlled study of fetal heart rate and fetal cardiac output.

STUDY OBJECTIVE: Spinal anesthesia often causes hypotension, with consequent risk to the fetus. The use of vasopressor agents has been highly recommended for the prevention of spinal anesthesia-induced hypotension during caesarean delivery. Many studies have shown that norepinephrine can provide more stable maternal hemodynamics than phenylephrine. We therefore tested the hypothesis that norepinephrine preserves fetal circulation better than phenylephrine when used to treat maternal hypotension consequent to spinal anesthesia. DESIGN: Prospective, randomized, double-blinded study. SETTING: Operating room. PATIENTS: We recruited 223 parturients with uncomplicated singleton pregnancies who were scheduled for elective caesarean section under combined spinal-epidural anesthesia. INTERVENTIONS: The patients received prophylactic intravenous infusion of either 0.08 µg/kg/min norepinephrine or 0.5 µg/kg/min phenylephrine for prevention of spinal anesthesia-induced hypotension. MEASUREMENTS: Changes in fetal heart rate and fetal cardiac output before and after spinal anesthesia were measured using noninvasive Doppler ultrasound. MAIN RESULTS: 90 subjects who received norepinephrine infusion and 93 subjects who received phenylephrine infusion were ultimately analyzed in the present study. The effects of norepinephrine and phenylephrine on the change of fetal heart rate and fetal cardiac output at 3 and 6 min after spinal block were similar. Although there was a statistically significant decrease in fetal cardiac output at 6 min after subarachnoid block initiation in both the norepinephrine group (mean difference 0.02 L/min; 95% CI, 0-0.04 L/min; P = 0.03) and the phenylephrine group (mean difference 0.02 L/min; 95% CI, 0-0.04 L/min; P = 0.02), it remained within the normal range. CONCLUSIONS: Prophylactic infusion of comparable doses of phenylephrine or norepinephrine has similar effects on fetal heart rate and cardiac output changes after spinal anesthesia. Neither phenylephrine nor norepinephrine has meaningful detrimental effects on fetal circulation or neonatal outcomes.

Interleukin 8 targeted contrast echocardiography is effective to evaluate myocardial ischemia-reperfusion injury in the rabbits.

Interleukin 8 (IL-8) is an important pro-inflammatory cytokine that recruits neutrophil to the areas of inflammation and has been implicated in myocardial ischemia reperfusion injury (MIRI). This study aimed to apply IL-8 targeted myocardial contrast echocardiography (MCE) to evaluate MIRI in rabbits. MCE imaging with IL-8 targeted microbubbles (MBIL-8) and control microbubbles (MBc) was performed in 40 Japanese white rabbits after brief proximal left anterior descending (LAD) partial occlusion for 30 min and subsequent reperfusion for 30 min, 60 min, 120 min and 180 min. Electrocardiogram and regional wall motion were assessed during occlusion and reperfusion. MCE demonstrated that IL-8 level rapidly increased in reperfused myocardial tissue and reached the peak after 120 min of reperfusion and lasted to 180 min of reperfusion. ELISA showed that the tendency of MCE data to change with reperfusion time was the same as that of IL-8 content. Taken together, these results suggest that targeted MCE with IL-8 antibody provides a new approach to noninvasive evaluation of MIRI using ultrasound imaging techniques.

[Effects of wearing long-term Ortho-K contact lens on corneal thickness and corneal endothelium].

OBJECTIVE: The current study evaluated the response of the cornea to more than 3 years of Ortho-K CL wearing by investigating the changes of corneal thickness and corneal endothelium. METHODS: One hundred and thirty-two subjects were fitted with Ortho-K CL (Dk 100), which were worn overnight or daily for more than 3 years. Central and para-peripheral corneal thickness and corneal endothelium were measured before and during this period by using A scan pachymeter and non contact specular microscope. RESULTS: There were no significant changes in corneal thickness (P < 0.05) and corneal endothelial polymegathism and pleomorphism could not be found after long-term wearing of Ortho-K CL (overnight or daily wear). CONCLUSIONS: This study shows that high Dk Ortho-K CL used for scientific reshaping treatment only induces mild corneal response. Therefore, the Ortho-K CL can be worn safely for long-term control of myopia.