Cerebrospinal fluid and arterial acid-base equilibria in spontaneously breathing third-trimester pregnant women.

BACKGROUND: Acid-base status in full-term pregnant women is characterised by hypocapnic alkalosis. Whether this respiratory alkalosis is primary or consequent to changes in CSF electrolytes is not clear. METHODS: We enrolled third-trimester pregnant women (pregnant group) and healthy, non-pregnant women of childbearing age (controls) undergoing spinal anaesthesia for Caesarean delivery and elective surgery, respectively. Electrolytes, strong ion difference (SID), partial pressure of carbon dioxide ( [Formula: see text] ), and pH were measured in simultaneously collected CSF and arterial blood samples. RESULTS: All pregnant women (20) were hypocapnic, whilst only four (30%) of the controls (13) had an arterial [Formula: see text] <4.7 kPa (P<0.001). The incidence of hypocapnic alkalosis was higher in the pregnant group (65% vs 8%; P=0.001). The CSF-to-plasma Pco2 difference was significantly higher in pregnant women (1.5 [0.3] vs 1.0 [0.4] kPa; P<0.001), mainly because of a decrease in arterial Pco2 (3.9 [0.3] vs 4.9 [0.5] kPa; P<0.001). Similarly, the CSF-to-plasma difference in SID was less negative in pregnant women (-7.8 [1.4] vs -11.4 [2.3] mM; P<0.001), mainly because of a decreased arterial SID (31.5 [1.2] vs 36.1 [1.9] mM; P<0.001). The major determinant of the reduced plasma SID of pregnant women was a relative increase in plasma chloride compared with sodium. CONCLUSIONS: Primary hypocapnic alkalosis characterises third-trimester pregnant women leading to chronic acid-base adaptations of CSF and plasma. The compensatory SID reduction, mainly sustained by an increase in chloride concentration, is more pronounced in plasma than in CSF, as the decrease in Pco2 is more marked in this compartment. CLINICAL TRIAL REGISTRATION: NCT03496311.

Cerebrospinal Fluid and Arterial Acid-Base Equilibrium of Spontaneously Breathing Patients with Aneurismal Subarachnoid Hemorrhage.

BACKGROUND: Hyperventilation resulting in hypocapnic alkalosis (HA) is frequently encountered in spontaneously breathing patients with acute cerebrovascular conditions. The underlying mechanisms of this respiratory response have not been fully elucidated. The present study describes, applying the physical-chemical approach, the acid-base characteristics of cerebrospinal fluid (CSF) and arterial plasma of spontaneously breathing patients with aneurismal subarachnoid hemorrhage (SAH) and compares these results with those of control patients. Moreover, it investigates the pathophysiologic mechanisms leading to HA in SAH. METHODS: Patients with SAH admitted to the neurological intensive care unit and patients (American Society of Anesthesiologists physical status of 1 and 2) undergoing elective surgery under spinal anesthesia were enrolled. CSF and arterial samples were collected simultaneously. Electrolytes, strong ion difference (SID), partial pressure of carbon dioxide (PCO2), weak noncarbonic acids (ATOT), and pH were measured in CSF and arterial blood samples. RESULTS: Twenty spontaneously breathing patients with SAH and 25 controls were enrolled. The CSF of patients with SAH, as compared with controls, was characterized by a lower SID (23.1 ± 2.3 vs. 26.5 ± 1.4 mmol/L, p < 0.001) and PCO2 (40 ± 4 vs. 46 ± 3 mm Hg, p < 0.001), whereas no differences in ATOT (1.2 ± 0.5 vs. 1.2 ± 0.2 mmol/L, p = 0.95) and pH (7.34 ± 0.06 vs. 7.35 ± 0.02, p = 0.69) were observed. The reduced CSF SID was mainly caused by a higher lactate concentration (3.3 ± 1.3 vs. 1.4 ± 0.2 mmol/L, p < 0.001). A linear association (r = 0.71, p < 0.001) was found between CSF SID and arterial PCO2. A higher proportion of patients with SAH were characterized by arterial HA, as compared with controls (40 vs. 4%, p = 0.003). A reduced CSF-to-plasma difference in PCO2 was observed in nonhyperventilating patients with SAH (0.4 ± 3.8 vs. 7.8 ± 3.7 mm Hg, p < 0.001). CONCLUSIONS: Patients with SAH have a reduction of CSF SID due to an increased lactate concentration. The resulting localized acidifying effect is compensated by CSF hypocapnia, yielding normal CSF pH values and resulting in a higher incidence of arterial HA.

Low noncarbonic buffer power amplifies acute respiratory acid-base disorders in patients with sepsis: an in vitro study.

Patients with sepsis have typically reduced concentrations of hemoglobin and albumin, the major components of noncarbonic buffer power (ß). This could expose patients to high pH variations during acid-base disorders. The objective of this study is to compare, in vitro, noncarbonic ß of patients with sepsis with that of healthy volunteers, and evaluate its distinct components. Whole blood and isolated plasma of 18 patients with sepsis and 18 controls were equilibrated with different CO2 mixtures. Blood gases, pH, and electrolytes were measured. Noncarbonic ß and noncarbonic ß due to variations in strong ion difference (ßSID) were calculated for whole blood. Noncarbonic ß and noncarbonic ß normalized for albumin concentrations (ßNORM) were calculated for isolated plasma. Representative values at pH = 7.40 were compared. Albumin proteoforms were evaluated via two-dimensional electrophoresis. Hemoglobin and albumin concentrations were significantly lower in patients with sepsis. Patients with sepsis had lower noncarbonic ß both of whole blood (22.0 ± 1.9 vs. 31.6 ± 2.1 mmol/L, P < 0.01) and plasma (0.5 ± 1.0 vs. 3.7 ± 0.8 mmol/L, P < 0.01). Noncarbonic ßSID was lower in patients (16.8 ± 1.9 vs. 24.4 ± 1.9 mmol/L, P < 0.01) and strongly correlated with hemoglobin concentration (r = 0.94, P < 0.01). Noncarbonic ßNORM was lower in patients [0.01 (-0.01 to 0.04) vs. 0.08 (0.06-0.09) mmol/g, P < 0.01]. Patients with sepsis and controls showed different amounts of albumin proteoforms. Patients with sepsis are exposed to higher pH variations for any given change in CO2 due to lower concentrations of noncarbonic buffers and, possibly, an altered buffering function of albumin. In both patients with sepsis and healthy controls, electrolyte shifts are the major buffering mechanism during respiratory acid-base disorders.NEW & NOTEWORTHY Patients with sepsis are poorly protected against acute respiratory acid-base derangements due to a lower noncarbonic buffer power, which is caused both by a reduction in the major noncarbonic buffers, i.e. hemoglobin and albumin, and by a reduced buffering capacity of albumin. Electrolyte shifts from and to the red blood cells determining acute variations in strong ion difference are the major buffering mechanism during acute respiratory acid-base disorders.

Homocysteine pathway and in vitro fertilization outcome.

A prospective study investigating whether levels of the homocysteine pathway are associated with pregnancy rate in in vitro fertilization (IVF). Prior to initiate treatments, women gave a blood sample to test serum and red blood cell (RBC) folates, homocysteine and vitamin B12. The main outcome was cumulative clinical pregnancy rate according to basal levels of serum and RBC folates, homocysteine and vitamin B12. Two-hundred-nine women were selected, of whom 56 achieved a clinical pregnancy (27%). Median [interquartile range] levels of RBC and serum folate in women who did and did not become pregnant were 328 and 263 ng/ml (p = 0.018) and 13.6 and 9.4 ng/ml (p = 0.001), respectively. The adjusted ORs (95%CI) of pregnancy in women with RBC and serum folate concentrations in the upper tertile of the distributions were 2.6 (1.4-5.1) and 1.9 (1.0-3.7), respectively. Women undergoing IVF treatments with higher levels of folate have a higher chance of clinical pregnancy.

Immunosuppressive drugs in whole blood: validation of a commercially available liquid chromatography/tandem mass spectrometry kit and comparison with immunochemical assays.

RATIONALE: In the determination of immunosuppressive drugs cyclosporine A (CSA), tacrolimus (TARO), sirolimus (SIRO), and everolimus (EVE) in whole blood there is an open debate about which is the best assay between immunochemistry and liquid chromatography/tandem mass spectrometry (LC/MS/MS). This work is aimed to explore this topic, focusing on the use of updated assays and the analysis of a large number of samples. METHODS: A certified in vitro diagnostic kit coupled with a medical device LC/MS/MS was validated and applied to the analysis of 1192 blood samples of patients treated with immunosuppressive drugs. The results were compared with those obtained by immunoassays. RESULTS: The LC/MS/MS approach was found to provide linear, stable, precise, and accurate results, with lower limits of quantification of 12.5, 1.1, 1.2, and 1.2 µg/L for CSA, TACRO, SIRO, and EVE, respectively. With this method 80 samples were analysed and reported within a single work shift. A correlation was observed between the LC/MS/MS and immunoassay data, with Spearman correlation coefficients of 0.980 (n = 260) for CSA, 0.836 for TACRO (n = 562), 0.898 for SIRO (n = 113), and 0.904 for EVE (n = 257). Passing-Bablock regression showed the presence of constant and proportional biases for most of the drugs. A Blond-Altman graph showed differences between the assays, with immunoassays generally overestimating the drugs. CONCLUSIONS: The LC/MS/MS certified kit was validated for the detection of immunosuppressant drugs in whole blood and it provided a high-throughput method that is consistent with the requirements of clinical laboratories. The comparison of patient data between LC/MS/MS and up-dated immunoassays shows that a significant discrepancy still exists, especially for CSA and SIRO, confirming the greater specificity associated with use of the LC/MS/MS assay Copyright © 2017 John Wiley & Sons, Ltd.

Folate, homocysteine and selected vitamins and minerals status in infertile women.

OBJECTIVES: Diet has been recognised as a crucial factor influencing fetal and maternal health. Adequate levels of substances such as homocysteine, folate and vitamin B12 have been associated with a higher rate of success in infertility treatments. Few data, however, are available on the average levels of micronutrients in the blood of reproductive-aged women, and specific values for adequate levels are not available. The aim of this cross-sectional study was to measure levels of folate, homocysteine and selected vitamins and minerals in women attending the infertility unit of an academic hospital for in vitro fertilisation (IVF). METHODS: Fasting venous blood samples were taken in the morning during routine screening before IVF in order to measure: serum folate, red blood cell (RBC) folate, total plasma homocysteine, vitamin B12, vitamin A, vitamin E, serum iron and serum ferritin. RESULTS: Among 269 women aged 37 ± 4 years, only 69% and 44% showed adequate levels of homocysteine and vitamin B12, respectively. Serum folate was appropriate in 78% of the study participants, but only a minority (12%) had a concentration of RBC folate regarded as optimal for the prevention of fetal neural tube defects. Serum levels of vitamin A, vitamin E, iron and ferritin were, however, appropriate in the vast majority of participants (>80%). CONCLUSION: Folate levels were largely inadequate among women attending an infertility clinic for IVF. Vitamin B12 levels were also found to be inadequate.

Reference range of serum calcitonin in pediatric population.

BACKGROUND: Children belonging to the multiple endocrine neoplasia type 2 (MEN 2) pedigree and carrying germline RET mutations are candidates for prophylactic thyroidectomy, the timing of which is based on the mutation-associated risk and the calcitonin (CT) levels. DESIGN: The aim of this study was to establish the reference range for serum CT in a pediatric population. The study included 2740 subjects (1339 females and 1401 males) ranging in age from 1 day to 16 years and undergoing blood testing for any medical condition not affecting serum CT. RESULTS: Overall, serum CT was undetectable in 61.5% of the samples and detectable in 38.5%. Detectable samples were more frequent in the first 2 years of life. Thereafter, undetectable samples became more frequent, particularly in females. Mean serum CT concentrations were higher in the first year of life (9.81 ± 8.8 pg/mL; range, 2.0-48.9 pg/mL) and the second year of life (4.56 ± 2.64 pg/mL; range, 2.0-14.7 pg/mL). A significant decrease of serum CT levels was observed thereafter (P < .001), and starting from the third year of life serum CT levels were similar to those found in adults. No gender difference was found in any age group. Based on these results, age-specific CT reference ranges are needed in the pediatric population, and especially in the first 2 years of life. CONCLUSIONS: This is the first study defining the reference range for serum CT in the pediatric population and large enough to be statistically meaningful. Our proposal may facilitate the process of decision making when dealing with gene carriers of MEN 2.

Interferon-ribavirin therapy induces serum antibodies determining 'rods and rings' pattern in hepatitis C patients.

A cytoplasmic antigen associated to inosine-5'-monophosphatedehydrogenase 2 eliciting specific antibodies (antirods and rings, RR) has been identified in patients with chronic hepatitis C who were exposed to pegylated interferon (PI) and ribavirin (RBV). The significance of anti-RR in these patients merits to be investigated. Sera from 88 chronic hepatitis C virus (HCV)-infected patients undergoing PI-RBV therapy were analysed for the presence of RR pattern by indirect immunofluorescence on HEp-2 substrate (Inova Diagnostics, San Diego, CA, USA). Anti-RR antibodies developed de novo in 32 patients independently of any demographic and virological feature, but with a significant association with cumulative exposure to PI-RBV (P = 0.0089; chi-square test). RR pattern was significantly more frequent in relapsers than in patients achieving sustained virological response (56% vs 30%; P = 0.0282, chi-square test). Anti-RR titre ranged from 1:80 to 1:1280, but significantly declined following treatment cessation. Anti-RR develop de novo in a substantial proportion of patients exposed to PI-RBV in relation to the duration of treatment exposure. Further investigations are necessary to unravel the mechanisms leading to the formation of these autoantibodies.