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Biomedical subjects

X Chanudet

Publications and source records attributed to X Chanudet.

At least 37 records · Page 2Linked to original sources
PubMed1993

Ambulatory monitoring of blood pressure in normal pregnancy.

The definition of hypertensive disorders in pregnancy is plagued by many difficulties, in part related to the limits of intermittent clinic readings of blood pressure. In order to better define the evolution of arterial blood pressure in normal subjects during normal pregnancy, casual and ambulatory (Spacelabs 90207, n = 22 or Diasys 200, n = 26) measurements of blood pressure were performed at gestational months 3, 6, and 9, in 48 normal women aged 18 to 39, both nulliparas (n = 19) and multiparas (n = 29). Ambulatory blood pressure levels were lowest in the first gestational trimester (24-hour mean: 104 +/- 8/63 +/- 6 mm Hg) and rose by a small increment during the last trimester (109 +/- 8/67 +/- 7 mm Hg at 8 months). Mean daytime ambulatory pressure was almost superimposable to clinic measurements at the three time points. A day-night variation in blood pressure level was detectable in all subjects at each recording. It is concluded that during normal pregnancy, ambulatory blood pressure levels were highest in the day and lowest at night at all gestational ages and increased only minimally before the ninth month. Reference values, as defined by the percentile distribution of daytime and nighttime systolic and diastolic blood pressure, may help define more precisely an alteration in the level and/or the circadian variation of arterial blood pressure during abnormal pregnancies.

Adult↗
PubMed1993

Active ambulatory blood pressures and urinary electrolytes in young male subjects with normal blood pressure or borderline hypertension.

OBJECTIVES: To examine the relationship between ambulatory blood pressure (ABP) and 24-h urinary electrolytes in young subjects with normal blood pressure or borderline hypertension. DESIGN: ABP shows a circadian profile. We question whether high- and low-level pressure spans might have a relationship with urinary salt output. METHODS: ABP was monitored by the SpaceLabs 5200 system in 182 young male subjects (aged 17-25 years) with normal or borderline office blood pressure. In all subjects, 24-h urinary sodium, potassium and chloride were measured. The mean values and SD of ABP during 24 h, or during the daytime (0900-2100 h) and night-time (2115-0845 h), were estimated. In addition, using a 'cumulative sum' method, 'active' (high-level) and 'passive' (low-level) spans of APB were identified in each subject. RESULTS: No relationship was found between 24-h urinary sodium, potassium or chloride and office systolic blood pressure. Also, no relationship was found between the electrolytes and mean value or SD of ABP during 24 h, daytime or night-time. In contrast, significant positive correlations were found between 24-h urinary sodium and active systolic and diastolic blood pressure. The present study suggests that the active blood pressure span is associated with salt intake in normal and borderline blood pressure groups.

Adult↗
PubMed1993

Fractal dimension of heart rate and blood pressure in healthy subjects and in diabetic subjects.

Beat-to-beat heart rate (HR) and blood pressure (BP) were measured by the Finapres system in 28 healthy subjects and 64 diabetic subjects. Autonomic controls in diabetic subjects were assessed by scoring 5 cardiovascular function tests (high score = abnormal control). The fractal dimension (FD) of HR (or SBP) was estimated as follows: Measuring the curve of 500 successive HRs with a rule of length L, one obtains N times L. The FD is the slope of the regression line of Log(N) versus Log(1/L) for different L. We found a lower FD of HR in diabetic subjects than in healthy subjects (1.35 +/- 0.10/1.44 +/- 0.09, p = 0.0002) and a similar FD of SBP in the 2 groups. In diabetic subjects, the FD of HR was negatively correlated with age (r = -0.27, p = 0.03), duration of diabetes (r = -0.33, p = 0.0078) and score of disautonomy (r = -0.43, p = 0.0007). So, heartbeat is more fractal in healthy status: a low fractal fluctuation is a sign of pathology.

Adult↗
PubMed1993

[Non-invasive ambulatory measurement of arterial pressure. Recommendations of the measurement group of the French Society of Arterial Hypertension].

Ambulatory blood pressure monitoring is being widely used now that relatively simple, reliable and well-tolerated, non-invasive blood pressure measuring devices have become available. The following recommendations are only to help physicians to use this technique in their daily practice: only use homologated devices; ambulatory monitoring should be performed during normal, everyday activities; at least one measurement of blood pressure should be taken every 1/4 hour during the day time (7 h-22 h) and every 1/2 hour during the night (22 h-7 h); the arm must be absolutely still and relaxed during the measurement; the function of the measuring device should be checked when the patient is fitted up and when the device is removed; data processing should provide at least: all values of blood pressure and heart rate, and their times of measurement, the mean values of systolic end diastolic blood pressure and heart rate during the day and during the night, the maximal and minimal systolic and diastolic blood pressure values, a chronogramme of the values. Reasonable indications of ambulatory blood pressure monitoring include: elimination of the "white coat" effect: to confirm the diagnosis of borderline hypertension; to demonstrate inversion of diurnal rhythm in severe hypertension; to demonstrate episodic hyper or hypotension; to confirm certain cases of toxaemia of pregnancy. It is also justified in the evaluation of antihypertension therapy, especially in cases of suspected drug resistance.

Ambulatory Care↗
PubMed1993

[Comparative evaluation of diabetic cardiac autonomic neuropathy by spectrum analysis and Ewing's tests].

METHODS: 62 diabetic patients of both sex (age: 46 +/- 16 yr, BMI: 26.1 +/- 4 kg/m2, casual blood pressure: 134 +/- 17/81 +/- 11 mmHg, mean age of diabetes: 11 +/- 9 yr) without cardiovascular medications were recruited. Autonomic involvement was based on the results from a battery of five cardiovascular tests as suggested by Ewing. The result of each test and a scoring system was considered. All patients underwent power spectral analysis (PSA) of digital blood pressure (BP) and RR intervals recorded in the recumbent position and after tilting with a Finapres monitor. The percentage of total power (0.025-0.4 Hz) computed in the low-frequency band (0.070-0.139 Hz) computed in the low-frequency band (0.070-0.139 Hz) was chosen as a sympathetic index (sigma Ind). Results of tests were correlated with sigma Ind. RESULTS: 24 patients (39%) have an autonomic involvement. The most affected tests are: the Valsalva maneuver (VAL): 16% RR response from lying to standing (LS): 25%, sustained handgrip (SHG): 30%, postural hypotension (PH); 57%, deep breathing (DB): 87%. Correlations coefficients of cardiovascular tests and sigma Ind are: VAL/sigma Ind (SBP tilt): r = 0.277, p = 0.029; Val/sigma Ind (DBP tilt): r = 0.318, p = 0.012; VAL/sigma Ind (RR tilt): ns. PH/Ind sigma (SBP tilt): r = 0.391, p = 0.0017; PH/sigma Ind (DBP tilt): r = -0.296, p = 0.019; PH/sigma Ind (RR tilt): r = -0.308, p = 0.015, DB/sigma Ind (SBP tilt): r = 0.417, p = 0.0007; DB/sigma Ind (DBP tilt): r = 0.361, p = 0.0039; DB/sigma Ind (RR tilt): ns. Results of LS and SHG show no correlation with Ind sigma. Correlations between global autonomic score (GAS) and sigma Ind during tilting have the following values: GAS/sigma Ind (SBP tilt): r = -0486, p = 0.0001; GAS/sigma Ind (DBP tilt): r = -0.385, p = 0.002; GAS/sigma Ind (RR tilt): r = -0.411, p = 0.0009. CONCLUSIONS: The so-called sympathetic index computed from PSA are well correlated with autonomic tests. They allow an early detection of sympathetic involvement in diabetics patients. These results are to consider while managing these subjects.

Autonomic Nervous System Diseases↗
PubMed1993

[Cardiovascular autonomic neuropathy and blood pressure variability in insulin-dependent diabetes].

The aim of this study was to analyse the role of cardiac autonomic neuropathy (CAN) in the changes of Blood-Pressure (BP) variability among insulin-dependent diabetics and to determine the relationship between BP variability and diabetic complications. Ambulatory BP monitoring was performed during 24 hours on 93 insulin-dependent diabetics and 77 normal subjects of similar age (Group 1). CAN was assessed by the cardiovascular autonomic function tests described by Ewing and the diabetics were divided in two groups: Group 2 including patients without CAN (n = 46) and Group 3 including patients with CAN (n = 47). The 24 h standard deviation (variability) and the day/night difference for systolic and diastolic BP were calculated for each subjects. Systolic and diastolic BP variability is more elevated in Group 3 than in the other groups during the diurnal period. Furthermore, the day/night difference of systolic and diastolic BP is lower in Group 3 compared to groups 2 and 3. Diabetic complications are also more frequently observed among diabetic patients with CAN (p < 0.001). So CAN seems to have two types of consequences on BP curve among diabetic patients: a decrease of day/night BP difference which can be responsible of relative hypertension during the night and an increase of BP variability. As frequency of diabetic retinopathy and nephropathy is more elevated among diabetic patients with CAN, it is possible that CAN plays a role in the occurrence of these complications. Therefore, a simple juxtaposition of these facts is also possible.

Adult↗
PubMed1993

[Is placebo necessary in a clinical trial on ambulatory blood pressure?].

Placebo has only a slight effect on ambulatory blood pressure (ABP). Some authors have suggested that the use of a placebo is not necessary in a study on the drugs effect on ABP. We demonstrate that even if placebo effect is small, the use of a placebo group is still necessary. Effects of one daily dose of 50 mg atenolol + 20 mg slow-released nifedipine (AN) were investigated. Patients with office DBP 90-110 mmHg received, in a double-blind protocol, either AN (group AN, n = 31) or a placebo (group P, n = 26). Ambulatory BP (ABP) and HR were measured (Spacelabs or Diasys systems) for 24 h before and one month after treatment. The 2 groups were comparable before treatment. After 1 month under treatment, ABP was significantly lower in the AN group, compared to the P group, and this over the whole day (p = 0.03 to p < 0.0001). The effect was the most important between 10-17 h (p < 0.0001). HR was significantly lower in the AN group during daytime (6-22 h), but not during the night (22-6 h). Over the whole group, placebo effect was not significant. However, ABP did decrease under placebo in subjects with high initial pressure. As a result, an analysis without data from the placebo group led to an overestimation of the effects of the drug.

Adult↗
PubMed1993

[Unusual complication of venous thrombosis of the upper limb: pulmonary hypertension].

Although less frequent than that of the lower limbs, venous thrombosis of the upper limbs may cause pulmonary embolism. This embolism is usually moderate and facilitated by the delay or absence of anticoagulant treatment. We report the case of a young man who had multiple and recurrent embolism consecutive to thrombosis of the axillary and subclavian veins and who rapidly developed pulmonary arterial hypertension on previously healthy lungs. There was no venous disease of the lower limb. After a more than 2 years' period, the pulmonary arterial hypertension is still moderate, but the patient remains under long-term antivitamin K therapy, this being the only available treatment capable of preventing a deterioration that would result in post-embolic cor pulmonale and ultimately require lung transplantation.

Adult↗
PubMed1992

Short-term representatives of daytime and night-time ambulatory blood pressures.

OBJECTIVE: To see whether measurements of ambulatory blood pressure during short-term daytime and night-time periods can represent complete daytime and night-time pressures accurately. DESIGN: Short-term measurements would be less uncomfortable for patients, easier to perform and could lead to fewer missing values, outliers or artefacts than full-day measurements, especially when repeated monitorings are required. METHOD: Ambulatory blood pressure was measured every 15 min for 24 h in 254 subjects with normal or borderline office blood pressure. Each pressure profile included at least 80 valid readings. Mean blood pressures for different 1-, 2-, 3-, 4-, 5- and 6-h spans were calculated and compared with mean daytime and night-time values using paired Student's t-test. RESULTS: One or two-hour spans of daytime blood pressure poorly represented mean daytime pressure. In contrast, 4-h readings, selected between 1000-2200 h represented daytime blood pressure with good accuracy. Over the total sample, 4-h mean blood pressure readings from 1000-2200 h differed from daytime readings by less than 2 mmHg and 2-h mean readings from 0300-0700 h differed from mean night-time readings by less than 1 mmHg. CONCLUSION: We suggest that 4-h measurements of ambulatory blood pressure during the daytime and 2-h measurements at night (with time spans selected as indicated as above) may be of value.

Adolescent↗
PubMed1992

Ambulatory blood pressure monitoring: a critical review of the current methods to handle outliers.

OBJECTIVES: To examine the methods to handle marginal readings in the analysis of ambulatory blood pressure. DESIGN: Data obtained from automatic ambulatory blood pressure monitoring include several 'outliers', i.e. readings at the frontier of physiologically acceptable ranges. Several methods have been used to handle these readings. We need to know whether using different methods to reject outliers leads to different results in the analysis of the data. If so, then it is important that a common method be used by different authors. METHODS: Ten reported methods to handle outliers were selected and applied to a large set of unpublished blood pressure profiles (Novacor Diasys system). We compared the effects of data rejection by these methods on the mean values and standard deviations (calculated over 24 h, daytime and night-time) of the remaining data. RESULTS: The different methods had quite different effects on the same data set. Depending on the method used, the discarded data varied from 1 to 17% of the total number of readings. Among the rejected data, readings that occurred in the daytime varied from 14 to 56%. Also, 'high-value' outliers varied from 1 to 60% of the rejected data. On average over the total sample, the rejection of outliers had only a small effect on the mean values of blood pressure. In contrast, it may strongly reduce the standard deviation of the readings. CONCLUSION: The study emphasized the need to use a common method to handle outliers in the analysis of ambulatory blood pressure data.

Adult↗
PubMed1992

[Chaotic aspect of heart rate and blood pressure in diabetic patients].

We applied a simplified version of the method suggested by Sugihara-May (Nature 1990: 344: 734-41) to study the control of heart rate (HR) in subjects with diabetes mellitus. The method aims to predict the future of an observation, if a series of observations on the same phenomenon is available. The method quantifies the fact that the series is predictable more or less longtime in the future. A random series is only shortly predictable in the future. HR and blood pressure were measured from beat to beat (by the Finapres system) for about 0.5 hours in 11 subjects with diabetes mellitus and normal blood pressure (group D) and in 10 controls subjects (group N). The subjects were sitting in a temperature-controlled quiet room, isolated from all external stimuli. The 2 groups were matched for age, and had the same weight and height. No difference was observed in mean-value and standard deviation (SD) of BP and HR between the 2 groups. Groups N/D: SBP = 112 +/- 11/123 +/- 11 mmHg, NS; DBP = 64 +/- 9/67 +/- 12 mmHg, NS; HR = 70 +/- 10/69 +/- 7 b/min, NS. Standard deviation of PAS = 5.5 +/- 1.6/5.7 +/- 1.9 mmHg, NS and SD of DBP = 3.5 +/- 0.9/3.4 +/- 1.2 mmHg, NS. The SD of HR (3.0 +/- 0.5/2.3 +/- 1.0 b/min in groups N/D) was somewhat lower in diabetics than in control subjects but the difference was not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1992

[Leg muscle bed syndrome: medical aspects of chronic forms].

Ninety two patients with lower leg pain of unknown cause underwent intramuscular pressure measurements by the needle technique described by Whitesides. Fifty four patients (59%) were found to have a chronic compartment syndrome. In these patients the intramuscular pressure was significantly increased at rest and after exercise as compared with normal subjects (13) and patients without the syndrome (38). Increased pressure at rest after exercise and a prolonged time for normalisation are the most commonly parameters in diagnosing chronic compartment syndrome. Tissue pressure measurement remains the basis of diagnosis for patients suffering from chronic compartment syndrome, indeed the clinical findings alone were found to be insufficient. Effective treatment consists of reduction of exertional activities or decompression by fasciotomy. The clinical results after fasciotomy were good and consistent with the findings of others.

Adult↗
PubMed1991

Atrial natriuretic factor and ambulatory blood pressure in young male subjects with normal or borderline office blood pressure.

Plasma levels of immuno-reactive atrial natriuretic factor (ANF) and ambulatory blood pressure were studied in 42 male subjects, aged 18 to 31 y, including 24 subjects with normal BP and 18 with borderline essential hypertension. ANF was measured in the morning (9 a.m.-12 a.m.), with the subjects in the supine and in the upright positions. Ambulatory BP was determined in all subjects every 15 minutes, for a whole 24 hour period. A scatter plot of office SBP or DBP versus upright or supine ANF suggested negative relationships (not significant). In contrast, the plasma ANF level was significantly correlated to ambulatory BP, especially to daytime BP (r = -0.52, p less than 0.001, between daytime SBP and upright ANF; r = -0.50, p less than 0.001, between daytime DBP and upright ANF). The data suggested that ANF is decreased in borderline hypertension, but the decrease can be evidenced only when BP is repeatedly determined to afford reliable data. An inhibition of the atrial release of ANF might be one possible mechanism contributing to the genesis of borderline essential hypertension.

Adult↗
PubMed1991

Ambulatory blood pressure in young subjects with familial history of hypertension.

Office blood pressure (BP), ambulatory blood pressure, (one determination every 15 min, over an entire 24 h span), were measured in 206 young male subjects, including 96 individuals having first degree familial history of hypertension (the F group) and 110 control subjects, matched for age, having no familial history of hypertension (the C group). In both groups, age ranged from 19 to 25 y. After a complete clinical and laboratory examination, all subjects were diagnosed as in good health. In particular, none had cardiac, renal or neurologic involvement. No subject received medication. Over the whole sample, 126 subjects had normal office BP and 80 had borderline office BP. No difference was found in office diastolic BP between the C and F groups. Office systolic BP was somewhat higher in the F group, when compared to the C group, but the difference was in the limit of statistical significance (0.05 less than p less than 0.10). In contrast, ambulatory systolic BP was significantly higher in the F group, when compared to the C group, the difference (0.05 less than p less than 0.001) occurred in daytime and at night. The above difference was more significant (p less than 0.02 to p less than 0.005) and persisted over larger time-spans when only subjects with normal office BP in the C and F groups are compared. In contrast, when restricted to the borderlines only, office and ambulatory BP was the same in subjects with and without familial history of hypertension.

Adult↗
PubMed1991

[Role of nocturnal hypertension in the deterioration of diabetic nephropathy].

UNLABELLED: Nocturnal hypertension (HTA), even a relative one, consequence of the change of the circadian pattern of blood pressure, may increase the whole day blood pressure in diabetic patients. MATERIALS AND METHODS: blood pressure has been measured every 15 minutes for 24 hours in 101 diabetic patients (43 insulin-dependent: type 1, 58 non insulin-dependent: type 2) by ambulatory blood pressure monitoring. 39 of them are hypertensive patients. Among these 101 patients, 19 have a nocturnal relative HTA corresponding in a lack or a negative difference between the diurn and the nocturn systolic or diastolic pressure (Group 1). The Group 2 is constituted by the 82 other patients; 24 hour-microalbuminuria was assayed by immunoturbidimetry for two days on end. RESULTS: patients of Group 1 were significantly older (p less than 0.01) than in the Group 2 (61 +/- 9 years vs 54 +/- 13 years). There was no significant change between the two Groups concerning the kind of diabetes (type 1 or type 2), the glycosylated hemoglobin and the frequency of degenerative complications. Microalbuminuria was significantly higher (p less than 0.01) in Group 1 (72 +/- 104 mg/24 h) than in Group 2 (20 +/- 30 mg/24 h). Both nervous dysautonomic cardiac failure and HTA treated were significantly higher in Group 1 than in Group 2, respectively (14/19 vs 28/82; p less than 0.01) and (15/19 vs 24/82; p less than 0.001). The causal blood pressure measurement was similar in the two Groups, but the whole day ambulatory blood pressure monitoring revealed a significant increase of the average of systolic (Group 1: 133 +/- 14 mmHg vs Group 2: 119 +/- 12 mmHg; p less than 0.001) and diastolic (Group 1: 81 +/- 12 mmHg vs Group 2: 75 +/- 8 mmHg; p less than 0.01) blood pressure during 24 hours. COMMENTS: the causal blood pressure measurement fails to appreciate the increase of the whole day blood pressure consequent to the suppression of nocturnal hypotension and sometimes to the occurrence of real nocturnal hypertension. This observation is probably in relation with the nervous dysautonomic cardiac failure and is associated with an increase of the microalbuminuria (patients with microalbuminuria greater than 30 mg/24 h--Group 1: 9/19 vs Group 2: 17/82; p less than 0.05). This situation can lead to an aggravation of degenerative complications. Such results should urge practitioners to assess the circadian pattern of blood pressure in diabetic patients more accurately.

Aged↗
PubMed1991

[Baroreflex and blood pressure variations in borderline hypertension of the young adult].

Blood pressure (BP) variability depends on external and internal factors. Among these, arterial baroreflex play an important role. The matter of this study is to assess the relationship between these two parameters in borderline hypertension (BL). Twenty six BL male hypertensive were recruited for the study, all gave informed consent. Age: 21 +/- 2 years, height: 177 +/- 8 cm, weight: 77 +/- 14 kg. An ambulatory BP monitoring was performed in each one using a Diasys (Novacor) recorder. Measurements were obtained each 15 minutes for 24 hours. Mean, standard deviation and variation coefficient (VC) of BP and heart rate (HR) were computed for 24 hours, daytime (9a.m.-7 p.m.), nighttime (11 p.m.-7 a.m.). Baroreflex sensitivity (BRS) was determined as the ratio of HR variation on systolic BP variation recorded with a Finapres device from the fourth phase of a Valsalva manoeuvre. Mean systolic and diastolic BP values for 24 hours, daytime and nighttime are: 129 +/- 11/73 +/- 13, 137 +/- 14/76 +/- 15, 114 +/- 11/69 +/- 12 mmHg. VC are: 12 +/- 3/15 +/- 3, 9 +/- 3/13 +/- 3, 10 +/- 3/13 +/- 4%. HR values are: 73 +/- 10, 84 +/- 14, 58 +/- 7 b/min, VC are: 24 +/- 5, 17 +/- 4, 17 +/- 7%. Index for BRS = 1.76 +/- 0.65%. There is no correlation between BRS and systolic BP or HR. BRS is correlated to the inverse of systolic daytime BP VC: r = -0.556, p = 0.003. There is no correlation with other parameters. This study provides evidence for a link between BRS and daytime BP variability in borderline hypertension.

Adult↗