Transfusion of packed red blood cells reduces selenium levels and increases lipid peroxidation in an in vivo ovine model.

BACKGROUND: Oxidative stress from surgery or critically illness has been shown to adversely contribute to morbidity and mortality. Recent studies record that oxidative stress is heightened following packed red blood cell (PRBC) transfusions and that products of oxidative stress accumulate as the PRBC ages. However, there are no studies that investigate if transfusion of aged PRBC actually increases the recipient's oxidative stress profile more than fresh PRBC. OBJECTIVE: To compare the effect of fresh vs aged PRBC transfusions on the recipient's oxidative stress using an ovine model. MATERIALS AND METHODS: Male sheep were transfused with either fresh (n = 6) or aged (n = 6) ovine PRBC, and serial blood samples taken. Plasma samples were analysed for lipid peroxidation using the thiobarbituric acid reactive substances (TBARS) assay. This served as an indicator of oxidative injury. Antioxidant function and trace element levels were also measured. RESULTS: Like human PRBC, the ovine PRBC had negligible selenium levels. Irrespective of age, PRBC transfusion was associated with reduced selenium levels and antioxidant function, which correlated with increased markers of lipid peroxidation. CONCLUSION: Transfusion of selenium poor PRBC can dilute selenium levels and compromise glutathione peroxidase antioxidant activity and thereby allow lipid peroxidation. As there was no evidence that aged PRBC induced more severe oxidative injury this suggests that selenium dilution is a key underlying mechanism. Further studies are needed to assess the impact of transfusion-related oxidative stress in massive transfusions.

Stored blood transfusion induces transient pulmonary arterial hypertension without impairing coagulation in an ovine model of nontraumatic haemorrhage.

BACKGROUND AND OBJECTIVES: Transfusion of blood products in particular older products is associated with patient morbidity. Previously, we demonstrated a higher incidence of acute lung injury in lipopolysaccharide-treated sheep transfused with stored blood products. As transfusion following haemorrhage is more common, we aimed to determine whether a 'first hit' of isolated haemorrhage would precipitate similar detrimental effects following transfusion and also disrupt haemostasis. MATERIALS AND METHODS: Anaesthetized sheep had 33% of their total blood volume collected into Leukotrap bags (Pall Medical), which were processed into packed red blood cells and cross-matched for transfusion into other sheep. After 30 mins, the sheep were resuscitated with either: fresh (<5 days old) or stored (35-42 days old) ovine blood followed by 4% albumin to replacement volume, albumin alone or normal saline alone and monitored for 4 h. RESULTS: The first hit of haemorrhage precipitated substantial decreases in mean arterial pressure however haemostasis was preserved. Transfusion of stored ovine blood induced (1) transient pulmonary arterial hypertension but no oedema and (2) reduced fibrinogen levels more than fresh blood, but neither induced coagulopathy. Thus, transfusion of stored blood affected pulmonary function even in the absence of overt organ injury. CONCLUSION: The fact that stored blood transfusions: (1) did not induce acute lung injury in contrast to previous lipopolysaccharide-primed animal models identifies the 'first hit' as an important determinant of the severity of transfusion-mediated injury; (2) impaired pulmonary dynamics verifies the sensitivity and vulnerability of the pulmonary system to injury.

Comparison of a supra-sternal cardiac output monitor (USCOM) with the pulmonary artery catheter.

BACKGROUND: Cardiac output (CO) cannot reliably be estimated by clinical examination. We aimed to measure the agreement between CO measurements using a supra-sternal Doppler monitor (USCOM, Coffs Harbour, Australia) and the pulmonary artery catheter (PAC). METHODS: The study was conducted in the intensive care unit of a tertiary teaching hospital. All patients with PAC in situ were eligible. Simultaneous CO readings were taken when clinically indicated. Investigators and clinicians were blinded to each other's results. The CO values used were the mean of three consecutive supra-sternal Doppler readings for patients with a sinus rhythm and seven for atrial fibrillation, and the mean of three thermodilution curves with acceptable form and values within 10% of each other for the PAC. Agreement was measured using both the paired t-test to calculate bias and limits of agreement and the intraclass correlation (ICC) coefficient. RESULTS: Ninety-four subjects were enrolled. From 89 subjects, 250 paired comparisons were obtained. USCOM monitor readings were unobtainable in five patients. Mean supra-sternal Doppler CO was 5.5 litre min(-1). Bias was -0.09 litre min(-1) and levels of agreement were +/- 2.92 litre min(-1) when compared with PAC. ICC was 0.46 (95% CI 0.36-0.56), and mean percentage difference was 19 (IQR 6-31)%. CONCLUSIONS: In our subjects, there was poor agreement between CO measurements done with the supra-sternal Doppler monitor and PAC.

Comparison of uterine concentrations of ethinyl estradiol and etonogestrel after use of a contraceptive vaginal ring and an oral contraceptive.

OBJECTIVE: To compare uterine tissue concentrations of ethinyl estradiol (EE) and etonogestrel (ENG) after one cycle of use of a contraceptive vaginal ring (NuvaRing; NV Organon, Oss, The Netherlands) or a combined oral contraceptive (COC). DESIGN: Randomized, open-label, pharmacokinetic study. SETTING: Obstetrics and gynecology unit. PATIENT(S): Eight premenopausal women about to undergo hysterectomy but otherwise healthy. INTERVENTION(S): One cycle (17-21 days) of NuvaRing or COC treatment that ended with surgical hysterectomy. MAIN OUTCOME MEASURE(S): Tissue concentrations of EE and ENG in uterine tissue samples taken from the upper myometrium and mid-myometrium, the cervical region, and the endometrium. RESULT(S): In both groups, concentrations of EE and ENG were similar in uterine tissue taken from the upper myometrium and mid-myometrium and the cervical region. However, compared with the COC group, concentrations of both hormones were markedly lower in tissue samples from the endometrium of women who had been treated with NuvaRing. CONCLUSION(S): Vaginal administration of hormones with NuvaRing did not produce elevated uterine concentrations of EE and ENG, compared with an oral contraceptive.

Efficacy and safety of a contraceptive vaginal ring (NuvaRing) compared with a combined oral contraceptive: a 1-year randomized trial.

This open-label, randomized, Phase III study compared the efficacy and tolerability of and compliance with NuvaRing, a combined contraceptive vaginal ring releasing 15 microg of ethinylestradiol (EE) and 120 microg of etonogestrel daily, with those of and with a combined oral contraceptive (COC) containing 150 microg of levonorgestrel (LNG) and 30 microg of EE. Subjects received NuvaRing or a COC for 13 cycles (3 weeks of ring/pill treatment followed by a 1-week ring-/pill-free period). A total of 1030 subjects (NuvaRing, n=512; COC, n=518) was randomized and started treatment (intent-to-treat [ITT] population). The percentage of women in the ITT population who completed the trial was 70.9% for the NuvaRing group and 71.2% for the COC group. Five in-treatment pregnancies occurred in each group, giving Pearl indices of 1.23 for NuvaRing and 1.19 for the COC. Compliance with both treatments was excellent and both were well tolerated. In conclusion, NuvaRing has comparable efficacy and tolerability with a COC containing 150 microg of LNG and 30 microg of EE and does not require daily dosing.

Follicular growth during contraceptive pill or vaginal ring treatment depends on the day of ovulation in the pretreatment cycle.

BACKGROUND: The aim of this study was to investigate whether the day of ovulation and the duration of a pretreatment cycle were related to the degree of follicular growth during subsequent contraceptive treatment. METHODS: This randomized, open-label study was performed in 40 healthy female volunteers, who were randomized by a computer-generated list after stratification for the ovulation day in a pretreatment cycle. They received two cycles of NuvaRing (21 subjects) or a combined oral contraceptive (COC) containing 30 microg ethinylestradiol and 150 microg levonorgestrel (19 subjects). Follicular diameter and serum hormone concentrations (FSH, LH, 17beta-estradiol, progesterone) were measured every third day. Data from treatment day 20 onwards were used for analysis. RESULTS: In the NuvaRing users, subjects with short cycles and early ovulations in the pretreatment cycle developed larger follicles during treatment than subjects with longer cycles and late ovulations. In the COC users, subjects with early ovulations in the pretreatment cycle developed larger follicles during treatment. CONCLUSIONS: The degree of follicular growth during treatment with a combined hormonal contraceptive is influenced by the duration of the pretreatment cycle and particularly by the duration of the follicular phase.

Ovarian function with the contraceptive vaginal ring or an oral contraceptive: a randomized study.

BACKGROUND: The effects on ovarian function of the combined contraceptive vaginal ring NuvaRing and a combined oral contraceptive (COC) were compared. METHODS: This randomized, open-label study was performed in 40 healthy female volunteers, who were randomized by a computer-generated list after stratification for the ovulation day in a pretreatment cycle. They received two cycles of NuvaRing (21 subjects) or a COC (30 microg ethinylestradiol and 150 microg levonorgestrel, 19 subjects). NuvaRing was started on cycle day 5, COC on cycle day 1. Follicular diameter, endometrial thickness and FSH, LH, 17beta-estradiol (E2) and progesterone concentrations were determined. RESULTS: The median maximum follicular diameter (maxFD) was < or =11 mm during treatment. In the first treatment cycle the maxFD was lower in the COC than in the NuvaRing group, due to the different starting procedures. MaxFD were not different in the second treatment cycle. In both groups, E2 and progesterone levels remained low during treatment. Ovulations did not occur. CONCLUSIONS: In both groups, ovarian activity was adequately suppressed. Due to the different starting procedures, lower ovarian activity was observed in the COC group in the first treatment cycle. In the second cycle, ovarian suppression was comparable with NuvaRing and COC treatment.

Efficacy, cycle control, and user acceptability of a novel combined contraceptive vaginal ring.

OBJECTIVE: To assess the contraceptive efficacy, cycle control, tolerability, and user acceptability of a novel combined contraceptive vaginal ring for up to 13 cycles. METHODS: Healthy women requesting contraception were enrolled in this 1-year multicenter study. Each ring released 120 microg of etonogestrel and 15 microg of ethinylestradiol daily, and was used for 3 weeks followed by a 1-week ring-free period. RESULTS: A total of 2322 women started treatment and so formed the intent-to-treat population. Subjects were followed for 23,298 cycles, equivalent to 1786 woman-years. Compliance was good with 85.6% of cycles in full compliance with specified criteria. In the intent-to-treat population, 21 pregnancies occurred, giving a Pearl Index of 1.18 (95% confidence interval 0.73, 1.80). Eleven of the pregnancies were attributable to noncompliance; the Pearl Index for the per-protocol population was 0.77 (95% confidence interval 0.37, 1.40). The mean incidence of withdrawal bleeding was 98.5% in all cycles. Irregular bleeding occurred in 5.5% of all cycles, and in most women, early or late withdrawal bleeding was restricted to spotting. The ring was well tolerated with a low incidence of adverse events; only 2.5% of all discontinuations were device related. The ring was easy to insert and remove and did not interfere with intercourse. Eighty-five percent of women were satisfied with the ring, and 90% would recommend its use to others. CONCLUSION: The ring is an effective contraceptive with excellent cycle control that is convenient, well tolerated, and highly acceptable to users.

Ovarian function with a novel combined contraceptive vaginal ring.

BACKGROUND: NuvaRing is a combined contraceptive vaginal ring designed for 3 weeks continuous use followed by a 1 week ring-free period. The present study evaluated ovarian function in women who were instructed to either adhere to, or deviate from, the recommended regimen of use. METHODS: In this open-label, randomized study, 45 women aged between 18 and 35 years used NuvaRing for one cycle in which the ring was used according to the recommended regimen. Women in group A (n = 15) then continued with a 'normal' 3 week period of ring use after which the restoration of ovarian function-i.e. the time to ovulation-for each woman was determined by daily vaginal ultrasound and serum hormone levels. For women in group B (n = 15), the second cycle consisted of only 3 consecutive days of ring use, after which each woman was monitored until ovulation. Women in group C (n = 15) were not permitted to start a second 'normal' cycle until a follicle with a diameter of 13 mm was observed by vaginal ultrasound; subsequently, the development of these follicles during the second cycle of ring use was monitored daily. RESULTS: Irrespective of the length of the second cycle, 3 weeks (group A) versus 3 days (group B), a new cohort of follicles needed to be recruited and the time to ovulation after ring removal was similar (19 versus 17 days). The median time needed to develop a follicle up to 13 mm in diameter (group C) was 11 days (range 8-21 days); none of the women ovulated after insertion of the second ring. CONCLUSION: NuvaRing is a highly effective, reversible method of hormonal contraception. Ovulation, at least until the stage of a 13 mm dominant follicle, is prevented and as little as 3 consecutive days of NuvaRing use interferes with follicle growth.