Elisabeth Krampl

Blood gases in pregnancy at sea level and at high altitude

Objective 1. To measure blood gases and minute ventilation in healthy women with normal pregnancies, compare with non‐pregnant women both at sea level and at high altitude; 2. to relate the results at altitude with duration of residence there.

Pregnancy at high altitude: a hyperviscosity state

Background.  Pregnancy at high altitude has been associated with intrauterine growth restriction and preeclampsia. These conditions, at sea level, have been linked to increased hematocrit and blood viscosity. The aim of this study was to investigate the effect of high altitude on maternal hemorheology.

Maternal cardiac function during pregnancy at high altitude

Objective  To investigate the maternal cardiovascular adaptation in pregnancy at high altitude, compared with that at sea level.

Psychological Reactions in Women Undergoing Fetal Magnetic Resonance Imaging

OBJECTIVE: To investigate womens psychological reactions when undergoing fetal magnetic resonance imaging (MRI), and to estimate whether certain groups, based on clinical and sociodemographic variables, differ in their subjective experiences with fetal MRI and in their anxiety levels related to the scanning procedure. METHODS: This study is a prospective cohort investigation of 62 women before and immediately after fetal MRI. Anxiety levels and subjective experiences were measured by questionnaires. Groups based on clinical and sociodemographic variables were compared with regard to anxiety levels and to the scores on the Prescan and Postscan Imaging Distress Questionnaire. RESULTS: Anxiety scores before fetal MRI were 8.8 points higher than those of the female, nonclinical, norm population (P<.001). The severity of the referral diagnosis showed a linearly increasing effect on anxiety level before MRI (weighted linear term: F1,59=5.325, P=.025). Magnetic resonance imaging was experienced as unpleasant by 33.9% (95% confidence interval [CI] 21.2–46.6%) and as hardly bearable by 4.8% (95% CI 0–17.5%) of the women. Physical restraint (49.9%, 95% CI 37.4–62.4%), noise level (53.2%, 95% CI 40.7–65.7%), anxiety for the infant (53.2%, 95% CI 40.7–65.7%), and the duration of the examination (51.6%, 95% CI 39.1–64.1%) were major distressing factors. CONCLUSION: Women who undergo fetal magnetic resonance imaging experience considerable distress, especially those with poor fetal prognoses. Ongoing technical developments, such as a reduction of noise, shortening the duration of the MRI, and a more comfortable position in open MRI machines, may have the potential to improve the subjective experiences of women during fetal MRI. LEVEL OF EVIDENCE: III

Maternal plasma glucose at high altitude

Objective To compare plasma glucose in pregnant women living at very high altitude; pregnant women living at sea level; non‐pregnant women living at very high altitude; and non‐pregnant women living at sea level.

Haemorheological adaptation during pregnancy in a Latin American population

Abstract: Objective: To investigate haemorheological changes during pregnancy in a Latin American population and compare to previously published data from Caucasian populations. Design: Cross‐sectional study. Population: 75 pregnant women at 10–36 wk of gestation and 17 non‐pregnant female controls in Lima, Peru. All the women and their ancestors for three generations were born and lived at sea level. Methods: Viscosity, haematocrit and plasma fibrinogen, albumin and total protein concentrations were determined in blood samples obtained after an overnight period of fasting. Results: At 10 wk of gestation, total protein concentration and plasma viscosity were above non‐pregnant levels by about 15% and subsequently decreased linearly with gestation. Fibrinogen concentration was increased in the first trimester; it then decreased to a nadir at about 20 wk and subsequently increased. Albumin concentration decreased linearly with gestation. Haematocrit decreased from pre‐pregnancy levels at 10 wk to a nadir at about 26 wk. Blood viscosity increased in the first trimester and then decreased with gestation to a nadir at about 26 wk. Conclusion: In the first trimester of pregnancy blood and plasma viscosity are increased and they subsequently fall with advancing gestation. Plasma viscosity reflects the changes in total protein concentration, and blood viscosity is dependent on the interplay of changes in plasma viscosity and haematocrit.

Maternal electrolyte and liver function changes during pregnancy at high altitude

BACKGROUND High-altitude (HA) hypoxia leads to profound cardiovascular, respiratory and electrolyte changes, and pregnancy at HA has been associated with increased incidence of preeclampsia and intrauterine growth restriction. OBJECTIVE To examine the effect of high altitude on maternal serum electrolytes and liver enzymes. DESIGN Cross-sectional study of 77 pregnant women at 6-40 weeks of gestation resident at HA (4370 m above sea level) and 80 at sea level (SL) and 13 and 15 nonpregnant women at each altitude, respectively. Serum electrolytes (sodium, potassium, calcium and phosphate), creatinine, bilirubin and liver enzymes (alkaline phosphatase (ALP), aspartate transaminase (AST) and gamma-glutamyl transferase (gamma-GT)) were measured. RESULTS Pregnancy at HA, compared to SL, was associated with higher serum osmolality (0.4%), sodium (0.7%), creatinine (14%) and phosphate (5%) concentrations and lower potassium (10%) concentration. Calcium and albumin-corrected calcium concentrations were higher at HA compared to SL in nonpregnant women (8%), with no difference in pregnant women. AST, gamma-GT and ALP concentrations were not significantly different between HA and SL, neither in pregnant nor in nonpregnant women. AST and gamma-GT were lower in pregnant compared to nonpregnant women (30%) at HA, whereas the difference was not significant at SL. Total bilirubin concentrations were higher at HA compared to SL by about 25% both in pregnant and in nonpregnant women, the difference reaching statistical significance only in the pregnant group. CONCLUSIONS Pregnancy at HA is associated with increased osmolality, sodium, creatinine, calcium, phosphate and total bilirubin concentrations. Liver enzyme activities are similar to SL.

Can aneroid sphygmomanometers be used at altitude

Mercury-independent devices are increasingly being used in clinical practice as mercury will soon be removed from clinical use as a result of environmental, health and safety concerns. The aim of this study was to evaluate the accuracy of a portable aneroid device in an adult population at high altitude by following the part of the protocol of the British Hypertension Society regarding comparison between device and observer. We examined 10 subjects in Cerro de Pasco, Peru, which is situated 4370 m above sea level. The aneroid device was initially calibrated at both high altitude and at sea level to ensure optimal function. Validation of the device was undertaken at high altitude by connecting it in parallel to two mercury sphygmomanometers. Eleven sequential same-arm measurements were taken from each subject by two trained observers, alternating between mercury sphygmomanometry and the aneroid device. Simultaneous mercury readings were also recorded for additional analysis. During calibration, all 60 comparisons between the aneroid and mercury sphygmomanometers were within 3 mm Hg both at sea level and at high altitude. At validation, the device achieved an A grade for both systolic and diastolic pressures and also fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The mean and standard deviation for systolic and diastolic pressures, respectively, were −1.32 (4.3) mm Hg and 3.7 (4.7) mm Hg in sequential analysis and −0.7 (2.6) mm Hg and −3.3 (2.7) mm Hg in simultaneous analysis. We conclude that the Riester-Exacta portable aneroid device can be recommended for use in an adult population at high altitude.