Leg Blood Pressure Research Articles

Cervical Aortic Arch with a New Twist

We report a case of cervical aortic arch (CAA) with unusual tortuosity in the mid thoracic descending aorta. The presentation of this case involving a 6-year-old girl with CAA reinforces clinical clues and associations. She was referred for catheterization to evaluate prominent right sided neck pulsations attributed to mild coarctation of the aorta with inability to image a normal aorta on an echocardiogram. At examination, the girl had intermittent arm–leg blood pressure discrepancies (e.g., right arm, 115/76; right leg, 98/67). When sitting, she had hyperdynamic neck pulsations in the right neck and a continuous murmur louder than a typical venous hum. Her small stature, dysmorphic features, and hypernasal speech were not shared by her twin brother. Chest X-ray did not confirm arch laterality or rib notching. Probable abnormal aortic arch development was diagnosed, and suspicion of velocardiofacial syndrome was supported with genetic testing, which confirmed 22q11 deletion. At catheterization, a patent foramen ovale facilitated catheter entry into the left ventricle. After left ventricular injection, the elongated ascending aorta with the right aortic arch and cervical extent plus the characteristic origin of the arch vessels was identified (Figs.1 and 2) [3]. Unique to this case was the ‘‘twist’’ seen in the mid thoracic descending aorta to the right of the spine before the aorta took a retroesophageal course and crossed to descend on the left. There was a mild gradient between the left ventricle (112/0, 10) and femoral artery (100/70; mean, 98). However, no discrete area of obstruction in the course of the aorta was identified. The congenital anomaly of CAA characterized by the cervical extent of the aortic arch with the apex positioned in the neck above the clavicle was first reported in 1914. Approximately 150 cases have been reported to date [1–3]. One proposal is that CAA develops during weeks 4 to 6 of fetal life from abnormal persistence of the third arch with involution of the left fourth arch, which locates the aortic arch to a more cervical position. This explanation also allows for the expected separate origins of the carotid arteries. There is no true innominate artery, and the last vessel off the aorta is the subclavian artery arising from the descending aorta contralateral to the arch. This is the pattern of CAA identified in patients with 22q11.2 deletion [1]. Clinically unifying to the diagnosis of the cervical aortic arch is the recognition of prominent pulsations in the neck and a cardiac murmur. Our patient should be followed for symptoms of vascular ring, aortic arch obstruction, aortic aneurysm, and anticipation of problems related to her confirmed 22q11.2 deletion. The unusual tortuosity of the aorta may be a new finding in the CAA complex.

Baroreflex and Muscle Metaboreflex

During heavy exercise, the arterial baroreflex and the reflexes evoked by the activation of those afferent nerve endings in the working skeletal muscles that are sensitive to metabolic changes (the so-called muscle metaboreflex) are hypothesized to be activated and, moreover, to interact in ways that lead to the modulation of the primary cardiovascular reflex responses. For the past few years, our group has been investigating the interaction between the arterial baroreflex and the muscle metaboreflex. We have focused our efforts in identifying the effects of muscle metaboreflex activation on the arterial baroreflex regulation of the cardiovascular hemodynamics and muscle sympathetic nerve activity (MSNA) in humans. In a series of studies, we have found that during muscle metaboreflex activation, dynamic carotid baroreflex responses are modulated, as exemplified by the augmentation of the MSNA, leg vascular conductance and blood pressure responses to carotid baroreflex unloading and the shorter suppression period of MSNA, diminished vasodilation, and reduced blood pressure response to carotid baroreflex stimulation. Furthermore, we have found that the modification of the arterial baroreflex-mediated beat-to-beat control of MSNA, which is seen during activation of the muscle metaboreflex (i.e., resetting and an increase in sensitivity), could be a consequence of the alteration in the arterial baroreflex control of both the occurrence and strength of the MSNA burst. In addition, we have demonstrated that the arterial baroreflex beat-to-beat control of MSNA is time-dependently modulated during isometric exercise. We suggest that the modulation of arterial baroreflex function during the activation of muscle metaboreflex is one of the mechanisms for increasing, or maintaining, blood pressure at the required pressure and thereby contributes to the regulation of the cardiovascular system during exercise.

Takayasu’s arteritis

Takayasu's arteritis is a rare disease that causes arterial inflammation with resulting stenosis or aneurysm of affected vessels. It primarily affects young females and has a predilection for the aorta, its primary branches, and the pulmonary arteries. Patients may present with symptoms of organ ischemia, such as stroke or claudication, or with signs of arterial stenosis, such as absent pulses or asymmetric blood pressures. Most patients require chronic immunosuppressive therapy to control inflammation. The foundation of therapy is glucocorticoids, which are often used in combination with other immunosuppressive agents, such as methotrexate, azathioprine, or mycophenolate mofetil. The goal of systemic therapy is to induce and maintain disease remission, often defined as the absence of new arterial lesions, lack of systemic symptoms, and ability to taper prednisone to less than 10 mg/d. Promising results have been seen with the use of agents directed against tumor necrosis factor in patients who have failed to maintain remission with standard therapies. Revascularization procedures such as percutaneous transluminal angioplasty (PTA) or bypass grafting are reserved for patients who have critical organ ischemia or severe extremity claudication. Bypass grafting has a lower restenosis rate than PTA and is the preferred method of restoring blood flow to affected organs. Frequent laboratory testing is recommended to monitor for drug toxicity and signs of disease relapse. At each clinic visit, physicians should auscultate for bruits over primary arterial branches and evaluate for asymmetry between arm and leg blood pressures. Biannual radiographic imaging with magnetic resonance or CT angiography is helpful to examine for evidence of new aortic aneurysms or arterial stenoses.

Exercise Evaluation of Upper- versus Lower-Extremity Blood Pressure Gradients in Pediatric and Young-Adult Participants

The aim of this study was to provide a normal reference for arm-leg blood pressure gradients in normal pediatric and young-adult patients before and after exercise. We assessed 216 normal participants by physical or echocardiographic exam, maximally tested using the James Cycle Protocol, with arm and leg blood pressures taken pre- and postexercise. Arm-leg gradients significantly increased from -5 mmHg at rest to 4, 2, and 1 mmHg 1, 3, and 4 min postexercise (p < .05). There was a small, statistically significant increase in arm-leg blood pressure with exercise, which is probably clinically insignificant. These data serve as a normal reference.

Exercise performance and blood pressure responses in children after stenting of aortic coarctation

Background The impact on cardiopulmonary function after endovascular stenting of an aortic arch obstruction is not well defined. We sought to determine in children following stenting whether they had normal cardiopulmonary responses to exercise and 24-h blood pressure (BP) monitoring. Methods Children after arch stenting without clinical evidence of persistent resting obstruction underwent a standard Bruce treadmill exercise test, echocardiographic arch flow assessment at rest and at peak exercise and 24-h ambulatory BP monitoring. Results There were 5 males (42%) and 7 females. Age at stent implantation was 14 ± 4 years and time from implantation to this study 2.5 ± 2.1 years. Mean arm systolic blood pressure at rest was 123 ± 12 mm Hg and at peak exercise 184 ± 31 mm Hg, with a mean arm to leg blood pressure gradient of 6 mm Hg (range − 6 to 68 mm Hg) and 33 mm Hg (range − 6 to 150 mm Hg), respectively. Left ventricular (LV) mass/height 3 index was 30.0 ± 6.7 with 5 children above the normal range. All children but 1 had a normal exercise endurance and heart rate response, with a maximal oxygen consumption and anaerobic threshold of 85 ± 20% and 99 ± 11% predicted normal, respectively. Four children had significant systolic hypertension, two diastolic hypertension and four a loss of the normal nocturnal BP reduction on 24-h recordings. Echocardiographic BP gradients do not correlate with non-invasive BP gradients. Resting and peak exercise BP and echocardiographic Doppler gradients did not identify children with abnormal 24-h BP monitoring. Conclusion Children with stented arch obstructions have normal exercise performance and the majority minimal increases in BP gradients at peak exercise. LV hypertrophy occurs commonly, but does not correlate with either residual arch gradients or abnormal 24-h BP measurements.

Passive Leg Movements and Passive Cycling Do Not Alter Arterial Leg Blood Flow in Subjects With Spinal Cord Injury

Subjects with a spinal cord injury (SCI) are at increased risk for cardiovascular disease-related secondary complications, such as pressure ulcers and attenuated wound healing. It has been suggested that passive exercise enhances blood flow via mechanical pump effects or reflex activation. The purpose of this study was to assess the effects of passive leg movements and passive cycling on the arterial circulation in subjects with SCI. Eight men with motor complete SCI and 8 male control subjects participated. Echo Doppler measurements were obtained to measure leg blood flow at rest, during and after 10 minutes of standardized passive leg movements, and during and after 20 minutes of passive leg cycling. Blood pressure was measured continuously, and total vascular resistance and leg vascular resistance were calculated. In both groups, no changes in leg blood flow, vascular resistance, or blood pressure were observed during or after the 2 interventions. The results of the study demonstrate that passive leg movements and passive cycling do not alter the arterial peripheral circulation in subjects with SCI or control subjects. Although the results do not support the use of passive movements or exercise for the prevention of cardiovascular disease-related secondary complications, physical therapists should not be dissuaded from using these techniques to address musculoskeletal concerns.

The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents

The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents

Variability of four limb blood pressure in normal neonates

Aims: To assess the variation in blood pressure (BP) between limbs in normal neonates. To assess whether comparison of arm and leg BP in neonates is reproducible enough to allow...

Dose-Dependent Effect of Caffeine on Reducing Leg Muscle Pain During Cycling

1513 PURPOSE: This double-blind, within-subjects experiment examined the effects of ingesting two doses of caffeine on perceptions of leg muscle pain and blood pressure during moderate intensity cycling exercise. METHODS: Low caffeine consuming college-aged males (N = 12) ingested one of two doses of caffeine (5 mg•kg−1 or 10 mg•kg−1 body weight) or placebo and 1 h later completed 30 min of moderate intensity cycling exercise (60% VO2peak). The order of drug administration was counterbalanced. Resting blood pressure and heart rate were recorded immediately before and 1 h after drug administration. Perceptions of leg muscle pain as well as work rate, blood pressure, heart rate, and oxygen uptake (VO2) were recorded during exercise. RESULTS: Caffeine increased resting systolic pressure in a dose-dependent fashion but these blood pressure effects were not maintained during exercise. Caffeine had a significant linear, dose-response effect on leg muscle pain ratings [F (2, 22) = 14.06, pp < .0001, eta2 = .56]. The mean pain intensity scores during exercise after ingesting 10 mg•kg−1 body weight caffeine, 5 mg•kg−1 body weight caffeine, and placebo were 2.1 ± 1.4, 2.6 ± 1.5, and 3.5 ± 1.7, respectively. CONCLUSION: Caffeine ingestion has dose-response effects on reducing leg muscle pain during exercise and these effects do not depend on caffeine-induced increases in systolic blood pressure during exercise.

Dose-dependent effect of caffeine on reducing leg muscle pain during cycling exercise is unrelated to systolic blood pressure

This double-blind, within-subjects experiment examined the effects of ingesting two doses of caffeine on perceptions of leg muscle pain and blood pressure during moderate intensity cycling exercise. Low caffeine consuming college-aged males ( N=12) ingested one of two doses of caffeine (5 or 10 mg·kg −1 body weight) or placebo and 1 h later completed 30 min of moderate intensity cycling exercise (60% V ̇ O 2 peak ). The order of drug administration was counter-balanced. Resting blood pressure and heart rate were recorded immediately before and 1 h after drug administration. Perceptions of leg muscle pain as well as work rate, blood pressure, heart rate, and oxygen uptake ( V ̇ O 2 ) were recorded during exercise. Caffeine increased resting systolic pressure in a dose-dependent fashion but these blood pressure effects were not maintained during exercise. Caffeine had a significant linear effect on leg muscle pain ratings [ F(2,22)=14.06; P<0.0001; η 2=0.56]. The mean (±SD) pain intensity scores during exercise after ingesting 10 mg·kg −1 body weight caffeine, 5 mg·kg −1 body weight caffeine, and placebo were 2.1±1.4, 2.6±1.5, and 3.5±1.7, respectively. The results support the conclusion that caffeine ingestion has a dose–response effect on reducing leg muscle pain during exercise and that these effects do not depend on caffeine-induced increases in systolic blood pressure during exercise.

Takayasu’s arteritis with bilateral renal artery stenosis: Unilateral kissing balloon angioplasty

Takayasu’s arteritis is a systemic non-specific vasculitis artery and bilateral stenosis at main renal arteries (Fig. 1). In primarily affecting the walls of large vessels. Renal arterial stenosis may be bilateral and usually seen with coexisting aortic involvement [1]. Percutaneous transluminal renal balloon angioplasty (PTRBA) is successful in up to 90% of cases and blood pressure control is achieved in approximately 68%. PTRA alone or supported with stent implantation has also been helpful in patients with suboptimal results after PTRBA and for managing recurrent restenosis [2]. Renal arterial bifurcational stenosis can be dilated by the kissing balloons technique, thus rendering difficult vascular surgery unnecessary [3]. In this article, a case with Takayasu arteritis that received the kissing balloon technique for a bifurcational renal artery stenosis was reported. An eleven-year-old girl was admitted to our clinic with complaints of malaise, headache, and exercise intolerance and diminished weight gain since she was four. Her physical examination showed right arm blood pressure of 110/70 mmHg, right leg blood pressure of 230/110 mm Hg. Her left radial, brachial and carotid pulses were not palpable and the pulses that belong to the lower extremities were palpable bilaterally. All laboratory findings were normal. Angiographic examination revealed narrowing of the right subclavian artery, bilateral carotid arteries, total occlusion of the left subclavian artery, normal left and right coronary arteries and minimal aortic insufficiency (Fig. 1). There was no stenosis at the pulmonary arteries. Aortography showed a bifurcational stenosis at an upper segment of the right renal

Quantification of leg edema in hypertensive patients treated with lercanidipine or amlodipine

To compare changes in leg volume and blood pressure by two different calcium antagonist - lercanidipine versus amlodipine - in hypertensive patients. Postmenopausal hypertensive patients (systolic blood pressure 150-179 or diastolic blood pressure 95/109 mmHg) were included. After 2-week single-blind placebo run-in, patients were randomized to 8 weeks of double-blind treatment with either 10 mg/day lercanidipine (N= 48) or 5 mg/day amlodipine (N= 44), with dosages doubling to 20 mg/day lercanidipine and 10 mg/day amlodipine after 4 weeks. Leg volume was measured by water displacement volumetry at baseline and after 4 and 8 weeks of treatment. The presence of edema was assessed by physicians and patients. Sitting blood pressure was recorded before leg volume measurements. A total of 77 patients (41 lercanidipine and 36 amlodipine) were included in the per protocol analysis. Leg volume increase from baseline to the end of 8-weeks of treatment was significantly greater in the amlodipine group (60.4 ± 8.6 ml) than in the lercanidipine group (5.3 ± 8.1 ml, p<0.001). The percentage of patients with evidence of edema (33.3% vs 9.8%, p=0.011) and with symptoms of leg swelling (63.9% vs 22%, p<0.001) was also greater on amodipine compared to lercanidipine. A positive correlation was found between the leg water displacement volume and the presence of edema or complaints of edema symptoms (p<0.001). Both drugs were effective in reducing blood pressure, and no correlation was found between blood pressure change and leg volume change in either group. Leg volume quantification with a water displacement technique demonstrated that leg volume increase and clinical edema of lercanidipine is significantly less than that of amlodipine, despite no significant differences in the antihypertensive effect.

Blood pressure changes in the leg on standing.

Normotensive and hypertensive patients develop peripheral arterial disease. The authors hypothesized that significant changes in lower extremity blood pressures occur upon standing, which could play a role in the pathogenesis of peripheral arterial disease. Forty-one subjects had blood pressure measurements performed in the arm and ankle in the supine and standing positions. The data show a marked increase in leg blood pressure on assuming the standing position, with mean increases of 65 mm Hg in systolic and 62 mm Hg in diastolic blood pressure in the lower extremities, compared with the arm on standing. In addition, the changes in diastolic pressure in the leg on standing were significantly correlated to height (r=0.47; p<0.002). These data reveal a previously unappreciated aspect of blood pressure, namely a large increase in lower extremity blood pressure values on standing, which may predispose to peripheral arterial disease.

The measurement of blood pressure and the detection of hypertension in children and adolescents.

Despite the publication of several expert committee guidelines for the measurement of blood pressure (BP) and the diagnosis of hypertension in children and adolescents, it was our perception and clinical experience that there still appeared to be a general lack of standardisation of BP measurement techniques and little consensus on the criteria for diagnosing hypertension. To investigate this further, we have conducted a postal survey of consultant-grade paediatricians who were members of the British Paediatric Association (BPA). A total of 1500 questionnaires were sent out and 708 analysable replies were received (47.1%). This showed that 68.6% of paediatricians routinely measured BP, at least on one occasion, in children or adolescents attending their outpatient clinics, 17.7% started at or soon after birth, 12.3% started at the age of 1 year, 20.0% at 3 years, 12.0% from 7 years of age and 3.5% from the age of 13. Only 60.5% reported that they had a choice of four or more different cuff sizes in their clinic. Forty-one percent of respondents reported that the BP was always or sometimes measured by nurses. Fifty-one percent of respondents measured diastolic BP at the phase of muffling of sound (Korotkoff phase IV), 31.9% used the disappearance of sound (phase V) whilst 15.9% claimed that they measured both end-points. The criteria for diagnosing a child as being hypertensive varied greatly; 17.9% reported that they responded to the systolic BP alone, 13.5% to the diastolic BP alone, 65.9% relied on both pressures, and 2.7% responded to either the systolic or diastolic pressure if it was raised. Furthermore, 12.9% diagnosed hypertension if the BP exceeded the 90th percentile in relation to age and 41.8% used the 95th percentile. However 45.3% of respondents employed a higher dividing line. In hospitalised children, leg blood pressures were measured routinely by 30.3%, although a further 44.0% would do so if aortic coarctation or other vascular diseases were suspected. Despite considerable variation in clinical practice, techniques and criteria, only 11.4% of clinicians would manage the patients themselves, with the remainder referring the child on to the appropriate specialist. The survey suggests a general lack of standardisation of BP measurement techniques and little consensus on the criteria for diagnosing hypertension amongst paediatricians. Simplified, shortened and updated guidelines on hypertension in paediatric practice and research are needed.

EFFECT OF HYPERPNEA ON LEG BLOOD FLOW

We have previously reported that leg VO2 and blood flow decreased with respiratory muscle loading and increased with respiratory unloading during maximal exercise but not during submaximal exercise in highly fit cyclists. We hypothesized that the normal hyperpnea of heavy exercise and its associated work of breathing is sufficient by itself to elicit sympatho-excitatory reflex effects from the respiratory muscles and decrease leg blood flow in subjects of moderate fitness levels. Five healthy subjects (age: 27 ± 2 yrs, VO2maz: 45.9 ± 1.4 ml/kg/min) performed eight randomized upright, single leg knee extension exercise (KE) at a work rate of 14.2 ± 0.8% of VO2maz. Subjects mimicked ventilation (VE) > 80% VEmaz (83.4 ± 5.3%) for all trials while hypocapnia was prevented. Breathing frequency, tidal volume, and inspiratory time was maintained constant under both normal (N; esophageal pressure (Pes) 19.1 ± 2.4 cmH2O) and inspiratory loaded breathing trials (via mesh screens) (L; Pes:123.8 ± 3.5% N). Leg blood velocity (MBV; via Doppler sonography) and blood pressure were measured continuously. KE exercise increased MBV approximately 2x resting levels. MBV was not significantly different, however between KE (23.0 ± 3.4 cm/s), KE+N (23.5 ± 3.6 cm/s) and KE+L (22.5 ± 3.7 cm/s). No significant difference was noted in heart rate between conditions although VO2 increased by 36 ± 3% with increased VE. In summary, we postulate that even with ventilatory work of 80% VEmaz under normal or loaded conditions, the respiratory system makes insufficient demands for VO2 and cardiac output to require any cardiovascular adjustment and is too small to activate sympathetic vasoconstrictor efferent output in moderately fit subjects. Support from American Heart Association, Parker B. Francis Foundation

Skeletal muscle perfusion in electrically induced dynamic exercise in humans

Leg blood flow, blood pressure and metabolic responses were evaluated in six men during incremental one-legged dynamic knee extension exercise tests (no load exercise-40 W); one performed with voluntary contractions (VOL) and one with electrically induced contractions (EMS). Pulmonary oxygen uptake was the same in both exercise modes, but the ventilatory coefficient was 2-5 L per L O2 higher in EMS than VOL (P < 0.05). Heart rate and mean arterial pressure were slightly higher with EMS than VOL at all exercise intensities reaching 138 (EMS) and 126 bpm (VOL), as well as 148 (EMS) and 137 mmHg (VOL) at 40 W, respectively (P < 0.05). Leg blood flow, oxygen uptake and conductance were similar in the two exercise modes. At 40 W, mean muscle blood flow was close to 200 (range: 165-220) mL 100 g-1 min-1, mean peak muscle oxygen uptake reached 230 mL kg-1 min-1, and mean conductance became as high as around 45 mL min-1 mmHg-1, and normalized for muscle size and arterial pressure it approached 100 mL min-1 100 g-1 100 mmHg-1. Lactate and ammonia efflux from the leg were higher with EMS than with VOL and the difference became larger with increasing exercise intensity (P < 0.05). Muscle glucose uptake was the same in each exercise mode. Femoral venous K+ concentration increased with exercise intensity and was higher with EMS than with VOL, reaching 5.1 (EMS) and 4.7 mmol L-1 (VOL) at 40 W (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Balloon angioplasty of native coarctation of the aorta: Midterm follow-up and prognostic factors

OBJECTIVES, This retrospective analysis was designed to examine the intermediate and long-term effects of balloon angioplasty for native coarctation of the aorta and to determine whether any factors are predictive of outcome. Balloon angioplasty for native coarctation of the aorta is controversial. Concerns exist over lack of long-term follow-up and possible formation of aneurysms. The role of transverse arch and isthmus hypoplasia after balloon dilation is unknown. Included in the study were all patients 3 days to 29 years old (mean age 4.6 years) referred for possible balloon dilation to the pediatric cardiac catheterization laboratory with evidence of a discrete coarctation of the aorta. The hemodynamic data, angiograms and clinical records of 102 patients were examined, with follow-up data from 2 to 117 months (median 36.2) available in 92 patients. Immediate success with balloon angioplasty was achieved in 93 (91.2%) of the 102 patients. Seventy-one patients (77.2%) with intermediate follow-up data (range 12 to 117 months) available are asymptomatic and normotensive, with insignificant arm to leg blood pressure gradients (< or = 20 mm Hg). Twenty-one patients (22.8%) with an initial successful result developed an increase in gradient 2 at 86 months after angioplasty, requiring reintervention in 18. Follow-up > 72 months is available in 17 patients, 16 of whom are normotensive and have not required additional intervention. No additional intervention was needed in 88.4% of older children and infants > 7 months old. Ten of the 13 surviving neonates who initially had a successful dilation required reangioplasty or operation 14 days to 10 months (median 4.6 months) after angioplasty. Transverse arch hypoplasia had minimal effect on follow-up blood pressure gradient, whereas isthmic hypoplasia was associated with reintervention in 50%. A small aneurysm was noted in 2 (1.9%) of 102 patients. Balloon angioplasty of native aortic coarctation is effective in infants and older children. In neonates, balloon angioplasty provides effective palliation only. Aneurysm formation is rare; however, lifetime follow-up is warranted.

External Abdominal Aortic Compression: A Study of a Resuscitation Manoeuvre for Postpartum Haemorrhage

External aortic compression is an emergency manoeuvre proposed to reduce postpartum haemorrhage and permit time for resuscitation and control of bleeding. To assess this technique, a prospective study was performed on twenty normal non-bleeding parturients. The abdominal aorta was compressed by firm pressure with a closed fist just above the umbilicus. Leg and arm arterial blood pressures were measured and femoral artery pulsation felt before, during and after compression. Leg blood pressure was completely obliterated in 55% and significantly reduced (P < 0.01) in a further 10% of subjects. All of these subjects with reduced or absent leg blood pressure also had obliteration of the femoral pulse with compression. Systemic arterial blood pressure was not significantly elevated by successful aortic occlusion. Discomfort with the manoeuvre was significantly increased (P < 0.05) in the group of subjects that had successful aortic occlusion. It is recommended that external aortic compression be considered in severe life-threatening postpartum haemorrhage, particularly during stabilisation or transport of the patient. This simple manoeuvre may be used as an adjunct to other measures and could prove of benefit, especially in locations or situations where advanced medical assistance is geographically or temporally removed.

Arm and leg blood pressures — are they really so different in newborns?

Controversy still exists over differences between upper and lower limb blood pressures (BP) in neonates. We measured upper arm and calf systolic (S) and diastolic (D) BP and heart rate (HR) using 2 Dinamap 847 instruments simultaneously every half minute for several measurement periods of 5–10 min. Nine healthy term newborns were studied in active (AS) and quiet (QS) sleep on post-natal days 1 and 5. The results were examined using unbalanced analyses of variance. Arm SBP was 62.3 ± 1.6 mmHg and DBP 35.5 ± 1.0 mmHg on day 1 in AS and QS. Calf values were not significantly different but were slightly higher (by 2–3 mmHg) in AS. Arm SBP and DBP rose by 8.5 and 5 mmHg, respectively, between days 1 and 5 but calf pressures rose less. Calf SBP and DBP were significantly lower (by 4.6 and 3.4 mmHg, respectively) than the arm values in QS on day 5. Arm SBP and DBP were dependent on post-natal age but not on sleep state while calf SBP and DBP and HR were dependent on both. Mean HR rose with age from 114 to 117.6 bpm in QS and from 118.6 to 122.4 bpm in AS. Our non-invasive BP measurements were similar to available invasive data. We postulate that differences in arm and calf vasoreactivity account for the different dependence on sleep state and for the unequal changes in arm and calf BE from days 1 to 5.

Maternal and fetal effects of the supine and pelvic tilt positions in late pregnancy

Material and fetal cardiovascular effects of position change were assessed in 20 women in late pregnancy. On changing from the left lateral to the supine position, there was a 45% reduction in leg blood flow, measured by strain gauge plethysmography. Arterial resistance, measured with Doppler ultrasound in the femoral, brachial and uterine arteries, remained unchanged, confirming the absence of compensatory vasoconstriction. There was no change in blood pressure (BP) in the leg, indicating no significant aortic compression, but a rise in maternal heart rate in the supine position suggested the presence of inferior vena cava (IVC) compression. Neither the left or the right pelvic-tilt position was associated with a significant change in leg blood flow or maternal heart rate compared to the supine position. A possible ‘sluice’ effect in the placental circulation was not confirmed, as fetal heart rate and umbilical Doppler resistance did not change in any position. In the absence of active vasoconstriction and significant aortic compression, IVC compression is the likely cause of the decrease in leg blood flow, and also of the previously demonstrated decrease in uterine blood flow. Leg BP and Doppler ultrasound measurements of uterine artery resistance may not be adequate measures of the effect of posture on uteroplacental perfusion.