The Valsalva maneuver and response revisited

Valsalva maneuver pressure recovery time is prolonged following spinal cord injury with correlations to autonomically-influenced secondary complications

PURPOSE

This work's purpose was to quantify rapid sympathetic activation in individuals with spinal cord injury (SCI), and to identify associated correlations with symptoms of orthostatic hypotension and common autonomically mediated secondary medical complications.

METHODS

This work was a cross-sectional study of individuals with SCI and uninjured individuals. Symptoms of orthostatic hypotension were recorded using the Composite Autonomic Symptom Score (COMPASS)-31 and Autonomic Dysfunction following SCI (ADFSCI) survey. Histories of secondary complications of SCI were gathered. Rapid sympathetic activation was assessed using pressure recovery time of Valsalva maneuver. Stepwise multiple linear regression models identified contributions to secondary medical complication burden.

RESULTS

In total, 48 individuals (24 with SCI, 24 uninjured) underwent testing, with symptoms of orthostatic hypotension higher in those with SCI (COMPASS-31, 3.3 versus 0.6, p < 0.01; ADFSCI, 21.2 versus. 3.2, p < 0.01). Pressure recovery time was prolonged after SCI (7.0 s versus. 1.7 s, p < 0.01), though poorly correlated with orthostatic symptom severity. Neurological level of injury after SCI influenced pressure recovery time, with higher injury levels associated with more prolonged time. Stepwise multiple linear regression models identified pressure recovery time as the primary explanation for variance in number of urinary tract infections (34%), histories of hospitalizations (12%), and cumulative secondary medical complication burden (24%). In all conditions except time for bowel program, pressure recovery time outperformed current clinical tools for assessing such risk.

CONCLUSIONS

SCI is associated with impaired rapid sympathetic activation, demonstrated here by prolonged pressure recovery time. Prolonged pressure recovery time after SCI predicts higher risk for autonomically mediated secondary complications, serving as a viable index for more "autonomically complete" injury.

Preeclamptic heart failure - perioperative concerns and management: a narrative review

Preeclampsia is an important cause of heart failure during pregnancy and the postpartum period. The aim of this review is to elucidate the pathophysiology and clinical features of preeclamptic heart failure and describe the medical and anesthetic management of these high-risk parturients. This article reviews the current evidence base regarding preeclamptic heart failure and its pathophysiology, types, and clinical features. We also describe the medical and anesthetic management of these patients during the peripartum period. Heart failure due to preeclampsia can present as either systolic or diastolic dysfunction. The management strategies of systolic heart failure include dietary salt restriction, diuresis, and cautious use of beta-blockers and vasodilators. Diuretics are the mainstay in the treatment of diastolic heart failure. In the absence of obstetric indications, vaginal delivery is the safest mode of delivery in these high-risk patients, and the use of an early labor epidural for analgesia is recommended. These patients would require increased invasive monitoring during labor and vaginal delivery. Neuraxial and general anesthesia have been used successfully for cesarean section in these patients but require crucial modifications of the standard technique. Uterotonic drugs have significant cardiovascular and pulmonary effects, and a clear understanding of these is essential during the management of these patients. Preeclamptics with heart failure require individualized peripartum care, as cardiac decompensation is an important risk factor for maternal and neonatal morbidity and mortality. These high-risk parturients benefit from timely multidisciplinary team inputs and collaborated management.

Thoracocervicofacial Purpura as a Presenting Symptom of Seizure Disorder: A Case Report

Introduction

Postictal thoracocervicofacial purpura (PTP) is a rare clinical sign after a seizure episode and may be the only objective sign seen in patients who are unaware of their own seizure disorder. Moreover, it can be the only reason a patient seeks medical care after a seizure activity.

Case Presentation

Herein, we report a 23-year-old, living alone and not known to have any medical illnesses, who presented to our emergency department complaining of asymptomatic purpuric facial rash extending to his neck and upper chest that started suddenly when he woke up that morning. Tongue and distal lateral thigh erosions were also noticed during physical examination, as well as conjunctival hemorrhage. In addition, the patient stated that he experienced similar prior episode of purpuric rash over the face, and disappeared uneventfully within 2 weeks. Blood work was remarkable for elevated urine creatinine (21,692 mg/L) and creatine kinase (1,207 mg/L). Given his clinical features and initial laboratory results, a diagnosis of PTP was made.

Conclusion

Patients who present with petechial rash over the chest, neck, malar area along with conjunctival hemorrhage as an only complaint should be suspected to have or evaluated for seizure disorder.

Synchronized wearables for the detection of haemodynamic states via electrocardiography and multispectral photoplethysmography

Cardiovascular health is typically monitored by measuring blood pressure. Here we describe a wireless on-skin system consisting of synchronized sensors for chest electrocardiography and peripheral multispectral photoplethysmography for the continuous monitoring of metrics related to vascular resistance, cardiac output and blood-pressure regulation. We used data from the sensors to train a support-vector-machine model for the classification of haemodynamic states (resulting from exposure to heat or cold, physical exercise, breath holding, performing the Valsalva manoeuvre or from vasopressor administration during post-operative hypotension) that independently affect blood pressure, cardiac output and vascular resistance. The model classified the haemodynamic states on the basis of an unseen subset of sensor data for 10 healthy individuals, 20 patients with hypertension undergoing haemodynamic stimuli and 15 patients recovering from cardiac surgery, with an average precision of 0.878 and an overall area under the receiver operating characteristic curve of 0.958. The multinodal sensor system may provide clinically actionable insights into haemodynamic states for use in the management of cardiovascular disease.

The Impact of Transcutaneous Spinal Cord Stimulation on Autonomic Regulation after Spinal Cord Injury: A randomized crossover trial

Importance

Individuals with spinal cord injury (SCI) have significant autonomic nervous system dysfunction. However, despite recent findings postulated to support that spinal cord stimulation improves dynamic autonomic regulation, limited scope of previous testing means the true effects remain unknown.

Objective

To determine whether transcutaneous spinal cord stimulation improves dynamic autonomic regulation after SCI.

Design

Single-blinded, randomized crossover trial with matched cohorts.

Setting

Academic autonomic physiology laboratory.

Participants

Two pairs of well-matched individuals with and without high-thoracic, complete SCI.

Interventions

Sub-motor threshold transcutaneous spinal cord stimulation delivered at T10-T11 using 120Hz, 30Hz, and 30Hz with 5kHz carrier frequency at separate autonomic testing sessions.

Main Outcomes and Measures

Baseline autonomic regulation was characterized with tests of above injury level sympathoexcitation (Valsalva's maneuver), sympathoinhibition (progressive doses of bolus intravenous phenylephrine), and below level sympathoexcitation (foot cold pressor test). At three subsequent visits, this testing battery was repeated with the addition of spinal cord stimulation at each frequency. Changes in autonomic regulation for each frequency were then analyzed relative to baseline testing for each individual and within matched cohorts.

Results

Uninjured controls demonstrated no autonomic deficits at baseline and had no changes with any frequency of stimulation. Contrasting this, and as expected, individuals with SCI had baseline autonomic dysfunction. In a frequency-dependent manner, spinal cord stimulation enhanced sympathoexcitatory responses, normalizing previously impaired Valsalva's maneuvers. However, stimulation exacerbated already impaired sympathoinhibitory responses, resulting in significantly greater mean arterial pressure increases with the same phenylephrine doses compared to baseline. Impaired sympathoexcitatory response below the level of injury were also further exacerbated with spinal cord stimulation. At baseline, neither individual with SCI demonstrated autonomic dysreflexia with the noxious foot cold pressor test; the addition of stimulation led to a dysreflexic response in every trial, with greater relative hypertension and bradycardia indicating no improvement in autonomic regulation.

Conclusions and Relevance

Transcutaneous spinal cord stimulation does not improve autonomic regulation after SCI, and instead likely generates tonic, frequency-dependent sympathoexcitation which may lower the threshold for autonomic dysreflexia.

Splanchnic Nerve Modulation Effects on Surrogate Measures of Venous Capacitance

Background Splanchnic nerve modulation (SNM) is an emerging procedure to reduce cardiac filling pressures in heart failure. Although the main contributor to reduction in cardiac preload is thought to be increased venous capacitance in the splanchnic circulation, supporting evidence is limited. We examined changes in venous capacitance surrogates pre- and post-SNM. Methods and Results This is a prespecified analysis of a prospective, open-label, single-arm interventional study evaluating the effects of percutaneous SNM with ropivacaine in chronic heart failure with elevated filling pressures at rest and with exercise. Patients underwent cardiopulmonary exercise testing with invasive hemodynamic assessment pre- and post-SNM. Blood pressure changes with modified Valsalva maneuver and hemoconcentration, pre- and post-SNM were compared using a repeated measures model. Inferior vena cava diameter and collapsibility (>50% decrease in size with inspiration), and presence of bendopnea pre- and post-SNM were also compared. Fifteen patients undergoing SNM (age 58 years, 47% women, 93% with left ventricular ejection fraction ≤35%) were included. After SNM, changes in systolic blood pressure during Valsalva (peak-to-trough) were greater (41 versus 48 mm Hg, P=0.025). Exercise-induced hemoconcentration was unchanged (0.63 versus 0.43 g/dL, P=0.115). Inferior vena cava diameter was reduced (1.59 versus 1.30 cm, P=0.034) with higher collapsibility (33% versus 73%, P=0.014). Bendopnea was less (47% versus 13%, P=0.025). Conclusions SNM resulted in increased venous capacitance, associated decreased cardiac preload, and decreased bendopnea. Minimally invasive measures of venous capacitance could serve as markers of successful SNM. Long-term effects of SNM on venous capacitance warrant further investigation for heart failure management. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03453151.

Use of Valsalva Maneuver to Detect Late-Onset Delayed Orthostatic Hypotension

BACKGROUND

Standard autonomic testing includes a 10-minute head-up tilt table test to detect orthostatic hypotension. Although this test can detect delayed orthostatic hypotension (dOH) between 3 and 10 minutes of standing, it cannot detect late-onset dOH after 10 minutes of standing.

METHODS

To determine whether Valsalva maneuver responses can identify patients who would require prolonged head-up tilt table test to diagnose late-onset dOH; patients with immediate orthostatic hypotension (onset <3 minutes; n=176), early-onset dOH (onset between 3 and 10 minutes; n=68), and late-onset dOH (onset >10 minutes; n=32) were retrospectively compared with controls (n=114) with normal head-up tilt table test and composite autonomic scoring scale score of 0.

RESULTS

Changes in baseline systolic blood pressure at late phase 2 (∆SBPVM2), heart rate difference between baseline and phase 3 (∆HRVM3), and Valsalva ratio were lower and pressure recovery time (PRT) at phase 4 was longer in late-onset dOH patients than in controls. Differences in PRT and ∆HRVM3 remained significant after correcting for age. A PRT ≥2.14 s and ∆HRVM3 ≤15 bpm distinguished late-onset dOH from age- and sex-matched controls. Patients with longer PRT (relative risk ratio, 2.189 [1.579-3.036]) and lower ∆HRVM3 (relative risk ratio, 0.897 [0.847-0.951]) were more likely to have late-onset dOH. Patients with longer PRT (relative risk ratio, 1.075 [1.012-1.133]) were more likely to have early-onset than late-onset dOH.

CONCLUSIONS

Long PRT and short ∆HRVM3 can help to identify patients who require prolonged head-up tilt table test to diagnose late-onset dOH.

The Role of Transcranial Doppler in Detecting Patent Foramen Ovale

Air embolic signals detected in the intracranial arteries using transcranial Doppler after intravenous injection of agitated saline bubbles indicate right-to-left cardiac shunting. They prove that emboli from venous sites can bypass the lungs and flow to the intracranial arteries. The Valsalva maneuver immediately after an intravenous injection of agitated saline bubbles helps the air bubbles pass through the shunt. If the air embolic signal appears in the intracranial arteries without the Valsalva maneuver, the shunting is highly significant to the etiology of embolism. Transcranial Doppler to detect air embolic signals after intravenous injection of agitated saline bubbles may not be mandatory to diagnose and treat patent foramen ovale; however, as with echocardiography, transcranial Doppler is considered a noninvasive, convenient, and low-cost investigation. The test should be helpful to confirm the significance of the corresponding patent foramen ovale.

Deep breathing alleviates propofol-induced pain: a prospective, randomized, single-blind study

PURPOSE

Propofol is commonly used to induce general anesthesia; however, the pain caused during propofol injection is a disadvantage. This study aimed to assess whether deep breathing attenuates propofol injection pain.

METHODS

This prospective, single-blind, randomized controlled study included 200 patients who were scheduled to undergo elective surgery under general anesthesia and randomly and equally divided them into group D and group C. The observers were not blinded to the pain-relieving modality, but each patient was blinded. Group D patients were requested to repeatedly take deep breaths throughout general anesthesia induction with propofol. Group C patients were requested to breathe in the usual manner. The intensity of propofol injection pain was evaluated using the visual analog scale (VAS). Furthermore, we recorded the patients' pain expressions, including grimace or hand-withdrawal, and the recalled pain measured using a VAS in the post-anesthetic care units (PACU).

RESULTS

Compared with patients in group C, those in group D showed significantly reduced VAS scores for propofol injection pain (20 [interquartile range (IQR): 0-48] vs. 37 [IQR 9-65], P = 0.017) and recalled pain in the PACU (16 [IQR 0-32] vs. 26 [IQR 0.5-51], P = 0.031). Further, the grimace incidence was significantly lower in group D (18%) than in group C (45%) (P < 0.001). There was no significant difference in the incidence of pain at induction, recalled pain, or hand-withdrawal.

CONCLUSIONS

Deep breathing could be an easy, safe, and inexpensive method for reducing pain during propofol injection.

Valsalva-derived Measures and Phenylephrine Test in Patients With Heart Failure With Reduced Ejection Fraction Receiving Comprehensive Neurohormonal Blockade Drug Therapy: A 5-year Event-free Survival Analysis

BACKGROUND

To assess the relationships between Valsalva- and phenylephrine test-derived measures and outcome in patients with heart failure with reduced ejection fraction (HFrEF) receiving comprehensive neurohormonal blockade pharmacotherapy.

METHODS AND RESULTS

Data from 56 patients with HFrEF (mean left ventricle ejection fraction of 32 ± 6%) subjected to Valsalva and phenylephrine tests were analyzed retrospectively. Baroreflex-related (Valsalva-ratio and blood pressure-RR interval slope from phase IV) and non-baroreflex-related measures (systolic blood pressure rise in phase IV [ΔSBP_{PHASE_IV}], and pulse amplitude ratio [PAR]) were calculated from Valsalva. Short-term outcomes (HF-related hospitalization, implantable cardioverter-defibrillator shock or all-cause death within 24 months from examination) and long-term outcomes (implantable cardioverter-defibrillator shock or all-cause death within 60 months) were analyzed. The end point occurred in 16 and 18 patients, for the short- and long-term outcomes, respectively. A low ΔSBP_{PHASE_IV} identified patients at risk in the long term, as evidenced by a low vs high ΔSBP_{PHASE_IV} comparison (square-wave response patients assigned to low ΔSBP_{PHASE_IV} group, P = .002), and Cox model (hazard ratio 0.91, 95% confidence interval 0.86-0.96, P < .001), and tended to identify patients at risk in the short term outcome (hazard ratio 0.95, 95% confidence interval 0.91-1.00, P = .055). There was a tendency toward a higher event-free survival in the low PAR group (low vs high PAR; hazard ratio 0.44, 95% CI 0.17-1.18, P = .104).

CONCLUSIONS

Non-baroreflex-related measures obtained from Valsalva-namely, ΔSBP_{PHASE_IV} and PAR-might carry prognostic value in patients with HFrEF receiving neurohormonal blockade pharmacotherapy.

Obstetric Anesthesia and Heart Disease: Practical Clinical Considerations

Maternal morbidity and mortality as a result of cardiac disease is increasing in the United States. Safe management of pregnancy in women with heart disease requires appropriate anesthetic, cardiac, and obstetric care. The anesthesiologist should risk stratify pregnant patients based upon cardiac disease etiology and severity in order to determine the appropriate type of hospital and location within the hospital for delivery and anesthetic management. Increased intrapartum hemodynamic monitoring may be necessary and neuraxial analgesia and anesthesia is typically appropriate. The anesthesiologist should anticipate obstetric and cardiac emergencies such as emergency cesarean delivery, postpartum hemorrhage, and peripartum arrhythmias. This clinical review answers practical questions for the obstetric anesthesiologist and the nonsubspecialist anesthesiologist who regularly practices obstetric anesthesiology.

Team-Based Care of Women With Cardiovascular Disease From Pre-Conception Through Pregnancy and Postpartum: JACC Focus Seminar 1/5

The specialty of cardio-obstetrics has emerged in response to the rising rates of maternal morbidity and mortality related to cardiovascular disease (CVD) during pregnancy. Women of childbearing age with or at risk for CVD should receive appropriate counseling regarding maternal and fetal risks of pregnancy, medical optimization, and contraception advice. A multidisciplinary cardio-obstetrics team should ensure appropriate monitoring during pregnancy, plan for labor and delivery, and ensure close follow-up during the postpartum period when CVD complications remain common. The hemodynamic changes throughout pregnancy and during labor and delivery should be considered with respect to the individual cardiac disease of the patient. The fourth trimester refers to the 12 weeks after delivery and is a key time to address contraception, mental health, cardiovascular risk factors, and identify any potential postpartum complications. Women with adverse pregnancy outcomes are at increased risk of long-term CVD and should receive appropriate education and longitudinal follow-up.

Supraventricular Tachycardia

The term paroxysmal supraventricular tachycardia encompasses a heterogeneous group of arrhythmias with different electrophysiologic characteristics. Knowledge of the mechanism of each supraventricular tachycardia is important in determining management in the office, at the bedside, and in the electrophysiology laboratory. Paroxysmal supraventricular tachycardias have an abrupt onset and offset, typically initiating and terminating with premature atrial ectopic beats. In the acute setting, both vagal maneuvers and pharmacologic therapy can be effective in arrhythmia termination. Catheter ablation has revolutionized therapy for many supraventricular tachycardias, and newer techniques have significantly improved ablation efficacy and decreased periprocedural complications and procedure times.

Attenuation of Splanchnic Autotransfusion Following Noninvasive Ultrasound Renal Denervation: A Novel Marker of Procedural Success

BACKGROUND

Renal denervation has no validated marker of procedural success. We hypothesized that successful renal denervation would reduce renal sympathetic nerve signaling demonstrated by attenuation of α-1-adrenoceptor-mediated autotransfusion during the Valsalva maneuver.

METHODS AND RESULTS

In this substudy of the Wave IV Study: Phase II Randomized Sham Controlled Study of Renal Denervation for Subjects With Uncontrolled Hypertension, we enrolled 23 subjects with resistant hypertension. They were randomized either to bilateral renal denervation using therapeutic levels of ultrasound energy (n=12) or sham application of diagnostic ultrasound (n=11). Within-group changes in autonomic parameters, office and ambulatory blood pressure were compared between baseline and 6 months in a double-blind manner. There was significant office blood pressure reduction in both treatment (16.1±27.3 mm Hg, P<0.05) and sham groups (27.9±15.0 mm Hg, P<0.01) because of which the study was discontinued prematurely. However, during the late phase II (Iii) of Valsalva maneuver, renal denervation resulted in substantial and significant reduction in mean arterial pressure (21.8±25.2 mm Hg, P<0.05) with no significant changes in the sham group. Moreover, there were significant reductions in heart rate in the actively treated group at rest (6.0±11.5 beats per minute, P<0.05) and during postural changes (supine 7.2±8.4 beats per minute, P<0.05, sit up 12.7±16.7 beats per minute, P<0.05), which were not observed in the sham group.

CONCLUSIONS

Blood pressure reduction per se is not necessarily a marker of successful renal nerve ablation. Reduction in splanchnic autotransfusion following renal denervation has not been previously demonstrated and denotes attenuation of (renal) sympathetic efferent activity and could serve as a marker of procedural success.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02029885.

The Valsalva manoeuvre versus tourniquet for venipuncture

BACKGROUND

During ultrasound-guided cannulation, venous filling is required for venipuncture. Tourniquet with an elastic tube at the axilla is the most common method to induce venous stasis for cannulation of the deep veins of the arm. Although effective, this method might be associated with short- and long-term complications. Valsalva manoeuvre has been used to produce venous filling in other extrathoracic veins. The aim of this observational study is to demonstrate the effect of Valsalva manoeuvre in respect of the elastic tourniquet on venous distention during echography-guided cannulation of the deep veins of the arm.

METHOD

Sixty-nine patients scheduled for cannulation of basilic or brachial vein were prospectively observed. Vein diameters were recorded at rest and after 10 s of Valsalva or tourniquet placement.

RESULTS

The mean difference between basilic vein diameters during tourniquet and Valsalva manoeuvre was 0.006 mm (95% confidence interval = -inf, 0.09) with a standard deviation of 0.5 mm (95% confidence interval = 0.5, 0.7; p > 0.01). The mean difference between brachial vein diameters during tourniquet and Valsalva manoeuvre was 0.04 mm (95% confidence interval = -0.23, 0.15) with a standard deviation of 0.8 mm (95% confidence interval = 0.7, 0.9; p > 0.01).

DISCUSSION

This increase in cross-sectional basilic and brachial vein diameters was not different to that obtained with the elastic tube tourniquet.

Effect of the Valsalva Maneuver on the Second Heart Sound

The Valsalva maneuver should be incorporated into the routine of auscultation even when a murmur is absent. Valsalva release affects the second heart sound. It is particularly helpful during detailed, non-perfunctory auscultation in patients with bundle branch block.

Intraoperative Valsalva maneuver: a narrative review

The Valsalva maneuver (VM) involves expiratory effort against a closed mouth and/or glottis in the sitting or supine position with the increased intraoral and intrathoracic pressure raised to 40 mmHg for 15-20 sec after which the pressure is suddenly released and the breathing restored to normal. Complex cardiovascular and other physiologic changes occur during the VM. The VM has been used for diagnostic and therapeutic reasons as well as intraoperatively during specific surgical procedures. Although the VM is usually safe, rare complications have been reported. This review examines the published literature surrounding the VM and explores the physiologic changes that occur during its performance. Attempts have been made to understand its intraoperative uses and complications and how these can be prevented.

Influence of a Commercial Antithrombotic Filter on the Caval Blood Flow During Neutra and Valsalva Maneuver

Anticoagulants are the treatment of choice for pulmonary embolism. When these fail or are contraindicated, vena cava filters are effective devices for preventing clots from the legs from migrating to the lung. Many uncertainties exist when a filter is inserted, especially during physiological activity such as normal breathing and the Valsalva maneuver. These activities are often connected with filter migration and vena cava damage due to the various related vein geometrical configurations. In this work, we analyzed the response of the vena cava during normal breathing and Valsalva maneuver, for a healthy vena cava and after insertion of a commercial Günther-Tulip® filter. Validated computational fluid dynamics (CFD) and patient specific data are used for analyzing blood flow inside the vena cava during these maneuvers. While during normal breathing, the vena cava flow can be considered almost stationary with a very low pressure gradient, during Valsalva the extravascular pressure compresses the vena cava resulting in a drastic reduction of the vein section, a global flow decrease through the cava but increasing the velocity magnitude. This change in the section is altered by the presence of the filter which forces the section of the vena cava before the renal veins to keep open. The effect of the presence of the filter is investigated during these maneuvers showing changes in wall shear stress and velocity patterns.

Cardiorespiratory Regulation in Migraine. Results in Children and Adolescents and Review of the Literature

To investigate autonomic regulation in juvenile migraine we studied 70 children and adolescents with migraine during the headache-free period and 81 healthy controls by cardiorespiratory function tests. Heart rate variability was analysed with time and frequency domain indices during spontaneous breathing at rest and during metronomic breathing. Changes of heart rate and blood pressure were studied during tilt-table test, active standing, Valsalva manoeuvre and sustained handgrip. We found significant differences in metronomic breathing, tilt-table test and Valsalva manoeuvre. We interpret our findings and results reported in the literature as pointing to a restricted ability of the system to rest, which supports therapies intending to further this ability. In autonomic tests, hyperreactivity in juvenile migraineurs changes to hyporeactivity and passive coping in adults. This might be explained by disturbances of raphe nuclei and the periaqueductal grey. It corresponds to psychological findings in juvenile migraineurs reporting hypersensitivity and repressed aggression and claiming learned helplessness.

Hemodynamic responses during and after multiple sets of stretching exercises performed with and without the Valsalva maneuver

OBJECTIVE

This study investigated the acute hemodynamic responses to multiple sets of passive stretching exercises performed with and without the Valsalva maneuver.

METHODS

Fifteen healthy men aged 21 to 29 years with poor flexibility performed stretching protocols comprising 10 sets of maximal passive unilateral hip flexion, sustained for 30 seconds with equal intervals between sets. Protocols without and with the Valsalva maneuver were applied in a random counterbalanced order, separated by 48-hour intervals. Hemodynamic responses were measured by photoplethysmography pre-exercise, during the stretching sets, and post-exercise.

RESULTS

The effects of stretching sets on systolic and diastolic blood pressure were cumulative until the fourth set in protocols performed with and without the Valsalva maneuver. The heart rate and rate pressure product increased in both protocols, but no additive effect was observed due to the number of sets. Hemodynamic responses were always higher when stretching was performed with the Valsalva maneuver, causing an additional elevation in the rate pressure product.

CONCLUSIONS

Multiple sets of unilateral hip flexion stretching significantly increased blood pressure, heart rate, and rate pressure product values. A cumulative effect of the number of sets occurred only for systolic and diastolic blood pressure, at least in the initial sets of the stretching protocols. The performance of the Valsalva maneuver intensified all hemodynamic responses, which resulted in significant increases in cardiac work during stretching exercises.

Doppler ultrasonography measurement of hepatic hemodynamics during Valsalva maneuver: healthy volunteer study

Purpose:

The aim of our study was to assess the hemodynamic change of liver during the Valsalva maneuver using Doppler ultrasonography.

Methods:

Thirty healthy men volunteers were enrolled (mean age, 25.5±3.64 years). The diameter, minimal and maximal velocities, and volume flow of intrahepatic inferior vena cava (IVC), middle hepatic vein (MHV), and right main portal vein (RMPV) was measured during both rest and Valsalva maneuver. These changes were compared using paired t-test.

Results:

The mean diameters (cm) of the intrahepatic IVC at rest and Valsalva maneuver were 1.94±0.40 versus 0.56±0.66 (P<0.001). The mean diameter (cm), minimal velocity (cm/sec), maximal velocity (cm/sec), and volume flow (mL/min) of MHV at rest and Valsalva maneuver were 0.60±0.15 versus 0.38±0.20 (P<0.001), -7.98±5.47 versus 25.74±13.13 (P<0.001), 21.34±6.89 versus 35.12±19.95 (P=0.002), and 106.94±97.65 versus 153.90±151.80 (P=0.014), respectively. Those of RMPV at rest and Valsalva maneuver were 0.78±0.21 versus 0.76±0.20 (P=0.485), 20.21±8.22 versus 18.73±7.43 (P=0.351), 26.79±8.85 versus 24.93±9.91 (P=0.275), and 391.52±265.63 versus 378.43±239.36 (P=0.315), respectively.

Conclusion:

The blood flow velocity and volume flow of MHV increased significantly during Valsalva maneuver. These findings suggest that hepatic vein might play an important role to maintain venous return to the heart during the maneuver.

Proposal intensity adequacy of expiratory effort and heart rate behavior during the valsalva maneuver in preadolescents

Background

When performing the Valsalva maneuver (VM), adults and preadolescents produce the same expiratory resistance values.

Objective

To analyze heart rate (HR) in preadolescents performing VM, and propose a new method for selecting expiratory resistance.

Method

The maximal expiratory pressure (MEP) was measured in 45 sedentary children aged 9-12 years who subsequently performed VM for 20 s using an expiratory pressure of 60%, 70%, or 80% of MEP. HR was measured before, during, and after VM. These procedures were repeated 30 days later, and the data collected in the sessions (E1, E2) were analyzed and compared in periods before, during (0-10 and 10-20 s), and after VM using nonparametric tests.

Results

All 45 participants adequately performed VM in E1 and E2 at 60% of MEP. However, only 38 (84.4%) and 25 (55.5%) of the participants performed the maneuver at 70% and 80% of MEP, respectively. The HR delta measured during 0-10 s and 10-20 s significantly increased as the expiratory effort increased, indicating an effective cardiac autonomic response during VM. However, our findings suggest the VM should not be performed at these intensities.

Conclusion

HR increased with all effort intensities tested during VM. However, 60% of MEP was the only level of expiratory resistance that all participants could use to perform VM. Therefore, 60% of MEP may be the optimal expiratory resistance that should be used in clinical practice.

The Valsalva maneuver can misdiagnose 'normal' as 'pseudonormal': a word of caution for an echocardiographic evaluation of diastolic function

OBJECTIVES

To identify differences in cardiac hemodynamic changes between the Valsalva maneuver and nitroglycerin (NTG) administration.

METHODS

Fifty-three subjects (37 men, 43 ± 12 years) with normal cardiac function [left ventricular ejection fraction ≥55%, early to late mitral inflow velocity ratio (E/A) ≥1, left atrial volume index ≤34 ml/m(2) and early diastolic mitral annulus velocity (E') ≥8 cm/s] were enrolled. Doppler parameters were determined at rest, during the Valsalva maneuver and after NTG administration.

RESULTS

Decreased E, A and E/A were observed both during the Valsalva maneuver and after NTG administration (p < 0.0001 for all). However, the reduction in E (ΔEValsalva: -30 ± 16 cm/s vs. ΔENTG: -17 ± 17 cm/s) and E/A (ΔE/AValsalva: -0.37 ± 0.28 vs. ΔE/ANTG: -0.19 ± 0.25) and the prolongation of the deceleration time (DT) of E (ΔDTValsalva: 105 ± 74 ms vs. ΔDTNTG: 83 ± 63 ms) were more prominent during the Valsalva maneuver than with NTG administration (p < 0.0001 for all). Particularly, a greater decrease in E' was observed during the Valsalva maneuver (ΔE'Valsalva: -3 ± 2 cm/s vs. ΔE'NTG: -2 ± 2 cm/s, p < 0.0001). Eighteen subjects (34%) showed ΔE/A ≥0.5 during the Valsalva maneuver; thus, they were mislabeled as 'pseudonormal', while only 3 subjects (6%) showed ΔE/A ≥0.5 after NTG administration.

CONCLUSIONS

The Valsalva maneuver not only decreases preload but also affects myocardial performance, thus, its use can result in the mislabeling of normal subjects as pseudonormal.

Olfactory Hallucinations without Clinical Motor Activity: A Comparison of Unirhinal with Birhinal Phantosmia

Olfactory hallucinations without subsequent myoclonic activity have not been well characterized or understood. Herein we describe, in a retrospective study, two major forms of olfactory hallucinations labeled phantosmias: one, unirhinal, the other, birhinal. To describe these disorders we performed several procedures to elucidate similarities and differences between these processes. From 1272, patients evaluated for taste and smell dysfunction at The Taste and Smell Clinic, Washington, DC with clinical history, neurological and otolaryngological examinations, evaluations of taste and smell function, EEG and neuroradiological studies 40 exhibited cyclic unirhinal phantosmia (CUP) usually without hyposmia whereas 88 exhibited non-cyclic birhinal phantosmia with associated symptomology (BPAS) with hyposmia. Patients with CUP developed phantosmia spontaneously or after laughing, coughing or shouting initially with spontaneous inhibition and subsequently with Valsalva maneuvers, sleep or nasal water inhalation; they had frequent EEG changes usually ipsilateral sharp waves. Patients with BPAS developed phantosmia secondary to several clinical events usually after hyposmia onset with few EEG changes; their phantosmia could not be initiated or inhibited by any physiological maneuver. CUP is uncommonly encountered and represents a newly defined clinical syndrome. BPAS is commonly encountered, has been observed previously but has not been clearly defined. Mechanisms responsible for phantosmia in each group were related to decreased gamma-aminobutyric acid (GABA) activity in specific brain regions. Treatment which activated brain GABA inhibited phantosmia in both groups.

The identification of right-to-left shunts using contrast transcranial Doppler ultrasound: performance and interpretation modalities, and absence of a significant side difference of cardiac micro-emboli

Cardiac and extracardiac right-to-left shunts can be identified by transesophageal echocardiography (TEE) as well as by transcranial Doppler ultrasound (TCD) using contrast agents that do not pass the lungs. Currently, the appropriate performance of a Valsalva manoeuvre (VM) to provoke the shunt, the use of different contrast agents and the classification of the TCD results are still under debate. In this study, we looked also at possible side effects of provoked cardiac micro-emboli in the left and right hemisphere. Seventy-one patients were investigated by both TEE and bilateral TCD of the middle cerebral arteries. The following protocol was applied in a randomized way: (1) Echovist-300 without VM; (2) Echovist-300, VM for 5 seconds starting 5 seconds after the beginning of contrast injection; (3) repetitive short VMs in between 2 and 13 seconds after the beginning of Echovist-300 injection; and (4) repetitive short VMs in between 2 and 13 seconds after the beginning of agitated saline injection. Only if one of the tests (2-4) was negative, this particular negative test was repeated. Use of Echovist-300, but not of saline yielded 100% sensitivity in the detection of TEE-proven shunts. The repetitive VM was slightly superior to the conventional VM. Introduction of a threshold of two or even three microbubbles produced less falsely positive TCD results in comparison to the TEE. There was no difference in microbubbles. TCD using Echovist-300 is a sensitive method to identify TEE-proven cardiac right-to-left shunts. Repetitive VM is an alternative to conventional VM.

Perioperative assessment of diastolic dysfunction

Assessment of diastolic function should be a component of a comprehensive perioperative transesophageal echocardiographic examination. Abnormal diastolic function exists in >50% of patients presenting for cardiac and high-risk noncardiac surgery, and has been shown to be an independent predictor of adverse postoperative outcome. Normalcy of systolic function in 50% of patients with congestive heart failure implicates diastolic dysfunction as the probable etiology. Comprehensive evaluation of diastolic function requires the use of various, load-dependent Doppler techniques This is further complicated by the additional effects of dehydration and anesthetic drugs on myocardial relaxation and compliance as assessed by these Doppler measures. The availability of more sophisticated Doppler techniques, e.g., Doppler tissue imaging and flow propagation velocity, makes it possible to interrogate left ventricular diastolic function with greater precision, analyze specific stages of diastole, and to differentiate abnormalities of relaxation from compliance. Additionally, various Doppler-derived ratios can be used to estimate left ventricular filling pressures. The varying hemodynamic environment of the operating room mandates modification of the diagnostic algorithms used for ambulatory cardiac patients when left ventricular diastolic function is evaluated with transesophageal echocardiography in anesthetized surgical patients.

Digital optical tomography system for dynamic breast imaging

Diffuse optical tomography has shown promising results as a tool for breast cancer screening and monitoring response to chemotherapy. Dynamic imaging of the transient response of the breast to an external stimulus, such as pressure or a respiratory maneuver, can provide additional information that can be used to detect tumors. We present a new digital continuous-wave optical tomography system designed to simultaneously image both breasts at fast frame rates and with a large number of sources and detectors. The system uses a master-slave digital signal processor-based detection architecture to achieve a dynamic range of 160 dB and a frame rate of 1.7 Hz with 32 sources, 64 detectors, and 4 wavelengths per breast. Included is a preliminary study of one healthy patient and two breast cancer patients showing the ability to identify an invasive carcinoma based on the hemodynamic response to a breath hold.

Postural change alters autonomic responses to breath-holding

OBJECTIVE

We used breath-holding during inspiration as a model to study the effect of pulmonary stretch on sympathetic nerve activity.

METHODS

Twelve healthy subjects (7 females, 5 males; 19-27 years) were tested while they performed an inspiratory breath-hold, both supine and during a 60 degrees head-up tilt (HUT 60). Heart rate (HR), mean arterial blood pressure (MAP), respiration, muscle sympathetic nerve activity (MSNA), oxygen saturation (SaO(2)) and end tidal carbon dioxide (ETCO(2)) were recorded. Cardiac output (CO) and total peripheral resistance (TPR) were calculated.

RESULTS

While breath-holding, ETCO(2) increased significantly from 41 +/- 2 to 60 +/- 2 Torr during supine (p < 0.05) and 38 +/- 2 Torr to 58 +/- 2 during HUT60 (p < 0.05); SaO(2) decreased from 98 +/- 1.5% to 95 +/- 1.4% supine, and from 97 +/- 1.5% to 94 +/- 1.7% during HUT60 (p = NS). MSNA showed three distinctive phases, a quiescent phase due to pulmonary stretch associated with decreased MAP, HR, CO, and TPR; a second phase of baroreflex-mediated elevated MSNA which was associated with recovery of MAP and HR only during HUT60; CO and peripheral resistance returned to baseline while supine and HUT60; a third phase of further increased MSNA activity related to hypercapnia and associated with increased TPR.

INTERPRETATION

Breath-holding results in initial reductions of MSNA, MAP, and HR by the pulmonary stretch reflex followed by increased sympathetic activity related to the arterial baroreflex and chemoreflex.

The Valsalva maneuver in Chagas disease patients without cardiopathy

OBJECTIVES

To perform a meta-analysis of studies using the Valsalva ratio (VR) in Chagas disease (ChD) patients without cardiopathy in comparison to control subjects in order to determine if vagal heart modulation is impaired in early forms of ChD.

METHODS

The medical literature was systematically searched and reviewed for cross-sectional studies in humans in which the Valsalva maneuver was used to evaluate the autonomic modulation of the heart in ChD patients without cardiopathy. The Hedges g statistic (software Medcalc v.9.4.0.0) was used to combine the results of all studies through the calculation of the summary standardized mean difference (SMD): the mean VR in controls minus the mean VR in ChD patients, divided by the pooled and adjusted standard deviation. The sample size necessary to detect this SMD with 80% of power was calculated using the G*Power software v.3.0.

RESULTS

The meta-analysis included 396 patients in 7 studies. Summary mean VRs were 1.87 +/- 0.39 ms in controls versus 1.74 +/- 0.40 ms in ChD without cardiopathy, leading to a statistically significant summary SMD of -0.310 (95% CI -0.513 to -0.106). Considering the summary SMD of -0.31, an alpha error of 0.05 and a 1:1 ratio of ChD and control patients, the estimated total sample size for a study with 80% power was 330 patients.

INTERPRETATION

ChD patients without cardiopathy have reduced VR values compared to healthy controls, indicating early vagal dysfunction. Most previous studies could not detect this impairment due to small study samples and insufficient statistical power.

Teaching cardiac autonomic function dynamics employing the Valsalva (Valsalva-Weber) maneuver

In this report, a brief history of the Valsalva (Valsalva-Weber) maneuver is outlined, followed by an explanation on the use of this approach for the evaluation of cardiac autonomic function based on underlying heart rate changes. The most important methodological and interpretative aspects of the Valsalva-Weber maneuver are critically updated, and some guidelines are established for simple application of the maneuver in a teaching or research laboratory setting. These include the hemodynamic and cardiac autonomic mechanisms involved, technical aspects such as the intensity and duration of the expiratory straining, frequency of maneuver sessions, training and posture of the individuals tested, different time- and grade change-dependent indexes of heart interval variation, and clinical application of the maneuver.

Humming Is as Effective as Valsalva’s Maneuver and Trendelenburg’s Position for Ultrasonographic Visualization of the Jugular Venous System and Common Femoral Veins

STUDY OBJECTIVE

The purpose of this study is to compare ultrasonographic visualization of the jugular and common femoral veins by using a novel technique (humming) and 2 conventional techniques (Valsalva's maneuver and Trendelenburg's position). The Valsalva's maneuver and Trendelenburg's position are common methods for producing venous distention, aiding ultrasonographically guided identification and cannulation of the jugular and common femoral veins. We hypothesize that humming is as effective as either Valsalva's maneuver or Trendelenburg's position for distention and ultrasonographic visualization of these procedurally important blood vessels. Herein, we investigate a new method of venous distension that may aid in the placement of central venous catheters by ultrasonographic guidance.

METHODS

Healthy, normal volunteers aged 28 to 67 years were enrolled. Each subject's internal jugular, external jugular, and common femoral veins were measured in cross-section by ultrasonograph during rest (baseline), humming, Valsalva's maneuver, and Trendelenburg's position. Three measurements were recorded per observation in each position. Subjects were used as their own controls, and measurements were normalized to percentage increase in diameter during each maneuver or position for later comparison.

RESULTS

The study population consisted of 7 subjects, with a mean age of 47 years. Cross-sectional area was calculated for each vessel in 3 groups: baseline/control, Valsalva, Trendelenburg, and humming. The mean percentage change (+/-SD) relative to baseline cross-sectional area of the jugular vessels for each subject were external jugular vein: humming 134%+/-25% (95% confidence interval [CI] 124.9% to 146.9%), Valsalva 136%+/-23% (95% CI 121.3% to 147.5%), Trendelenburg 137%+/-32% (95% CI 120.7% to 156.9%); internal jugular vein: humming 137%+/-27% (95% CI 119.4% to 148.2%), Valsalva 139%+/-24% (95% CI 122.4% to 148.7%), Trendelenburg 141%+/-35% (95% CI 116.5% to 156.5%); common femoral vein: humming 131%+/-15% (95% CI 120.4% to 139.1%), Valsalva 139%+/-18% (95% CI 127.9% to 150.4%), Trendelenburg 132%+/-24% (95% CI 113.3% to 142.9%).

CONCLUSION

All 3 maneuvers distended the external jugular, internal jugular, and common femoral veins compared to baseline. There was no important difference in magnitude of cross-sectional area between any of the 3 maneuvers when compared with one another. Humming shares many physiologic similarities to Valsalva's maneuver and may be more familiar and easier to perform during procedures such as ultrasonographically guided central venous catheter placement and insertion of external jugular intravenous catheters.

Mechanisms of Cough Syncope as Evaluated by Valsalva Maneuver

Successful treatment of cough syncope depends on the correction of various pathogenetic mechanisms among different patients. The valsalva maneuver (VM), which elicits hemodynamic responses mimicking coughs, has potential for investigating the individual pathogenesis of cough syncope. Eighteen consecutive patients suffering from cough-induced syncope were examined. All patients were asked to cough and to perform VM several times under continuous cerebral blood-flow velocity and blood pressure (BP) monitoring by transcranial Doppler and finger plethysmography. Eight patients demonstrated abnormal VM characterized by the absent BP overshoot following the relief of straining. Patients demonstrating abnormal VM had delayed BP recovery after cough (median, 16.4; range, 8.7-25.6 seconds) compared to those demonstrating normal VM (2.6, 1.3-3.8 seconds, p < 0.001). Seven of the 10 patients exhibiting normal BP overshoot during VM had stenotic arterial lesions in the cerebral or coronary circulation, whereas only one of the eight patients demonstrating absent BP overshoot had coronary artery disease (70% vs. 12.5%, p = 0.025). Other clinical profiles, body mass index, frequency of obstructive pulmonary disease and valsalva ratio did not differ between patients featuring normal and absent BP overshoot. In conclusion, the pathogenesis of cough syncope could be different between patients with normal and abnormal VM responses. Patients who had no BP overshoot during VM sustained prolonged hypotension after cough. The VM helps in discriminating among pathogenic mechanisms and guiding investigation and treatment for cough syncope patients.

Central hemodynamics during lung recruitment maneuvers at hypovolemia, normovolemia and hypervolemia. A study by echocardiography and continuous pulmonary artery flow measurements in lung-injured pigs

OBJECTIVE

The impact of lung-recruitment maneuvers on heart function at different volemic levels has not been studied in detail. We therefore investigated the effect on central hemodynamics of lung recruitment maneuvers at hypovolemia, normovolemia and hypervolemia in experimental lung injury.

DESIGN

Randomized, controlled, cross-over experimental study.

SETTING

Animal laboratory at a university hospital.

PARTICIPANTS

Eleven anesthetized and lung-lavaged pigs.

INTERVENTION

The animals were randomized to 10-s lung recruitment maneuvers followed by 30-s maneuvers (40 cm H(2)O airway pressure) or vice versa, performed under hypovolemia, normovolemia and hypervolemia.

MEASUREMENTS AND MAIN RESULTS

Left-ventricular end-diastolic diameter and cardiac output were measured before, during, and 1 min and 5 min after the lung recruitment maneuver and left-ventricular eccentricity index was calculated for before and during the maneuver. Cardiac output and left-ventricular end-diastolic diameter (within parentheses) decreased significantly during both the 10-s and 30-s lung recruitment maneuvers at hypovolemia, by a mean of 89% (35) and 92% (33), at normovolemia by 75% (33) and 86% (32), and at hypervolemia by 56% (32) and 64% (43), respectively. At hypovolemia, cardiac output was increased above baseline 1-5 min following the 30-s maneuver. Left-ventricular eccentricity index increased significantly during the maneuver, indicating right ventricular dysfunction.

CONCLUSIONS

In this animal lung injury model, lung recruitment maneuvers significantly decreased left-ventricular end-diastolic volume and cardiac output at hypovolemia. Hypervolemia did partly counteract this compromise. In addition, a marked right-ventricular dysfunction during the maneuver was found.

Single heartbeat cardiac tagging for the evaluation of transient phenomena

Many cardiac abnormalities are of a transient nature, creating a beat-to-beat variation in myocardial function. This work presents the cardiac imaging technique for the measurement of regional function during transient cardiac phenomena. All information necessary for the reconstruction of a cine loop is acquired within a single heartbeat, avoiding the temporal blurring introduced by segmented imaging due to the assumption of cardiac cycle periodicity. This method incorporates a gradient-optimized, high-efficiency EPI-SSFP sequence and TSENSE parallel imaging. For acquisitions with readout resolutions of 128,160, 192, and 256 points, the technique produced images with average temporal resolution of 35, 39, 43, and 52 ms and average spatial resolutions of 2.65, 2.12, 1.77, and 1.32 mm in the readout direction, respectively, and 2.88 and 2.08 mm in the phase encode direction for acceleration rates of 3 and 4, respectively. Local apparent strains in the single slice and measurements of ventricular end-systolic and end-diastolic areas were used as quantitative measures to validate the single heartbeat technique. To demonstrate the utility of the sequence, movie loops were acquired for multiple heartbeats in non-breath-held acquisitions as well as during a Valsalva maneuver. A heartbeat-interleaved acquisition allowed for the reconstruction of nonaccelerated images from R contiguous heartbeats. Images reconstructed from such data displayed tag blurring and reduced tag persistence due to motion and inter-heartbeat variability. Images acquired during the Valsalva maneuver demonstrated apparent beat-to-beat variability, visible both in the images and as changing strain patterns and ventricular volumes.

Design and implementation of dynamic near-infrared optical tomographic imaging instrumentation for simultaneous dual-breast measurements

Dynamic near-infrared optical tomographic measurement instrumentation capable of simultaneous bilateral breast imaging, having a capability of four source wavelengths and 32 source-detector fibers for each breast, is described. The system records dynamic optical data simultaneously from both breasts, while verifying proper optical fiber contact with the tissue through implementation of automatic schemes for evaluating data integrity. Factors influencing system complexity and performance are discussed, and experimental measurements are provided to demonstrate the repeatability of the instrumentation. Considerations in experimental design are presented, as well as techniques for avoiding undesirable measurement artifacts, given the high sensitivity and dynamic range (1:10(9)) of the system. We present exemplary clinical results comparing the measured physiologic response of a healthy individual and of a subject with breast cancer to a Valsalva maneuver.

Effects of thoracic blood volume on Valsalva maneuver

The Valsalva maneuver (VM) is frequently used to test autonomic function. However, the VM is also affected by changes in blood volume and blood volume redistribution. We hypothesized that even a standardized VM may produce a wide range of thoracic blood volume shifts. Larger blood volume shifts in some normovolemic individuals may be sufficient to induce decreases in blood pressure (BP) that preclude autonomic restoration of BP in phase II of the VM. To test this hypothesis, we studied 17 healthy volunteers aged 15-22 yr. All had similar vasoconstrictor responses when supine and upright and normal blood volume measurements. We assessed changes in thoracic blood volume by impedance plethysmography before and during the VM performed while subjects were supine. In some subjects, large decreases in BP were produced by thoracic hypovolemia. The maximum fractional decrease in BP correlated well (r(2) = 0.64; P < 0.001) with thoracic hypovolemia and with systolic BP at the end of phase II of the VM (r(2) = 0.67; P < 0.001). The BP overshoot in phase IV of the VM was uncorrelated to phase II changes, which suggests intact autonomic vasoconstriction. We conclude that the BP decrease during the VM is related to a variable decrease in thoracic blood volume that may be sufficient to preclude pressure recovery during phase II even with normal resting peripheral vasoconstriction. The VM depends on vascular as well as autonomic activation, which broadens its utility but complicates its analysis.

Tachycardia during the valsalva maneuver: a sign of normal diastolic filling pressures

Alteration of the loading conditions during the Valsalva maneuver is a helpful ancillary method in the noninvasive assessment of diastolic filling of the heart by Doppler echocardiography. When tachycardia is induced by the maneuver, mitral inflow velocity curves may become uninterpretable because of E velocity (the initial early diastolic velocity on the transmitral flow velocity curve) and A velocity (the velocity at atrial contraction on the transmitral flow velocity curve) wave fusion. To determine the clinical significance of the E velocity and A velocity wave fusion, our study assessed the relation between the heart rate response induced by the Valsalva maneuver and the left ventricular filling pressures measured during cardiac catheterization. In all, 77 patients performed the maneuver during continuous hemodynamic and electrocardiographic monitoring. The ratio between the baseline R-R interval and the shortest R-R interval during the maneuver was calculated. A ratio value higher than 1.1 was predictive of a pre-A pressure of less than 18 mm Hg (94% positive predictive value). Reflex tachycardia during the Valsalva maneuver and subsequent fusion of the E velocity and A velocity waves on the mitral velocity curves is a sign of normal left ventricular filling pressures.

Measures of cardiovascular autonomic regulation derived from spontaneous methods and the Valsalva maneuver

The response of heart rate to a given change of systolic blood pressure is a fundamental characteristic of the cardiovascular system. The assessment of baroreflex gain (BRS) as an index of baroreflex function is based on the quantification of RR interval changes related to blood pressure changes. The spontaneous sequence and cross spectral methods describe baroreflex gain derived from spontaneous fluctuations of these parameters, yielding the up sequence and down sequence BRS and the alfa index. Phase IV of the Valsalva maneuver is also used to calculate cardiac vagal baroreflex gain. In this study, we compared the two spontaneous methods and the Valsalva maneuver in assessing baroreflex gain in 56 healthy volunteers. The BRS values calculated from different methods were as follows: up sequence BRS 12 +/- 8.6 ms/mm Hg, down sequence BRS 10 +/- 6.1 ms/mm Hg, low frequency alfa index 12.1 +/- 8.2 ms/mm Hg, Valsalva BRS 9.7 +/- 7.2 ms/mm Hg. We found close relationship between baroreflex gain derived from up and down sequences (R = 0.91, p < 0.001), down sequence BRS and low frequency alfa index (R = 0.81, p < 0.001); significant correlation between up sequence BRS and low frequency alfa index (R = 0.65, p < 0.001), the Valsalva-derived BRS and down sequence BRS (R = 0.37, p = 0.043), but no correlation between the Valsalva BRS and up sequence BRS, the Valsalva BRS and low frequency alfa index. BRS values calculated by different methods decreased with increasing age. There was no influence of age on mean arterial blood pressure elevation in late phase II of the Valsalva maneuver, nor any indication that the Valsalva BRS was related to the MAP changes. We concluded that all of these methods are useful in calculating baroreflex gain, but owing to the differences in underlying physiological mechanisms, they are not necessarily in correlation with each other.

Optimizing the technique of contrast transcranial Doppler ultrasound in the detection of right-to-left shunts

BACKGROUND AND PURPOSE

A cardiac right-to-left shunt (RLS) can be identified by transesophageal echocardiography and transcranial Doppler ultrasound (TCD) with contrast agents and a Valsalva maneuver (VM) as a provocation procedure. This article applies the modalities of these tests detailed in previous studies to a large patient cohort and compares 2 contrast agents (saline and Echovist-300).

METHODS

Eighty-one patients were investigated by both transesophageal echocardiography and bilateral TCD of the middle cerebral arteries. The following protocol with injections of 10 mL agitated saline was applied in a randomized way: (1) no VM, (2) VM for 5 seconds starting 5 seconds after the beginning of contrast injection, and (3) repetition of the test with VM if the first test with VM was negative. The VM was performed for 5 seconds starting exactly 5 seconds after the beginning of saline injection. Thereafter, the same protocol was repeated with 10 mL Echovist-300 instead of saline.

RESULTS

Thirty-one patients had a cardiac RLS. The Echovist-300 investigation disclosed all these 31 shunts, but saline disclosed only 29 of them. Twenty-two had an RLS only in at least 1 of the above TCD tests, some of them even with a considerable shunt volume.

CONCLUSIONS

Contrast TCD performed with Echovist-300 but not with saline yields a 100% sensitivity to identify transesophageal echocardiography-proven cardiac RLSs. The TCD test should be repeated if negative the first time. This article gives detailed information for the optimization of the contrast TCD technique. Extracardiac shunts detected only during contrast TCD can have a considerable shunt volume and may allow for paradoxical embolism.

Impaired autonomic control of heart interval changes to Valsalva manoeuvre in Chagas' disease without overt manifestation

BACKGROUND

In the apparent indeterminate form of Chagas' disease, which lacks any overt clinical, electrocardiographic, and radiological manifestations of organ damage, lesions of the intrinsic autonomic innervation of heart are not striking features and evidences for cardiac autonomic dysfunction are elusive and conflicting.

OBJECTIVE

To evaluate the cardiac autonomic modulation based on Valsalva manoeuvre-associated heart interval variation in Chagas' disease subjects with apparent indeterminate form.

SUBJECTS AND METHODS

We examined 36 outpatient volunteers aged 15-51 years old (median: 36.5), in comparison with 52 healthy control individuals aged 17-49 years old (median: 29) (p<0.001). Each subject sequentially performed in the supine position three to four manoeuvres at an intra-oral pressure of 40 mm Hg during 20 s, under continuous DII lead electrocardiographic registration, and rate- and time-dependent indices of Valsalva manoeuvre-associated R-R interval variation were obtained. The t-test or the Mann-Whitney test was employed to compare the data between the groups.

RESULTS

No correlation was found between every index and age for the control group (p=0.39-0.71). The chagasic group presented similar basal to phase IV median increment (relative bradycardia) (23.7% vs. 22.7%; p = 0.63) and smaller basal to phase III median decrement of R-R interval (relative tachycardia) (-31.7% vs. - 35%; p=0.02) in comparison to the control group, respectively. The median Valsalva ratio showed a tendency for reduction in chagasics (1.78 vs. 1.90; p = 0.08). Prolonged median time (14.2 vs. 10.3 s; p < 0.001) and slowed median velocity (5.1%/s vs. 8.9%/s; p < 0.001) of the phases III-IV bradycardia were also observed in chagasic group. The majority (58.3%) of the chagasics presented exclusively at least one depressed, and 8.3% presented at least one enhanced index of rate- and/or time-dependent heart interval responses beyond the 25th or 75th control percentiles, and 27.8% presented at least one depressed and other enhanced index, while 5.6% showed all indices within the control interquartile range. All the indices outside the 25th or 75th control percentiles were noted in 13.9% of chagasics.

CONCLUSION

Chagas' disease subjects without overt manifestations presented variable and subtle depression and less frequent enhancement or normality of the rate- and time-dependent tachycardia and bradycardia reflex responses related to Valsalva manoeuvre, which demonstrates distinct patterns of finely disturbed cardiac sinus parasympathetic and sympathetic modulation, probably due to inflammatory or autoimmunological damage of intrinsic innervation and/or to autoantibodies-induced derangement in neurotransmitter receptors.

The effects of the simulated Valsalva maneuver, liver compression, and/or Trendelenburg position on the cross-sectional area of the internal jugular vein in infants and young children

We calculated the effects of the simulated Valsalva (V), liver (L) compression, and Trendelenburg (T) position on the cross-sectional area (CSA) of the right internal jugular vein by using planimetry (Aloka ultrasound machine) in 84 infants and young children. Eight combinations of positions and interventions were studied for each patient, with the patient supine, in the T position, during the simulated V maneuver, with L compression and a combination of maneuvers. Data were analyzed by using Friedman's chi(2) test and Wilcoxon's signed rank test. An increase of >25% in the CSA of the internal jugular vein was considered significant. In infants, the maximal mean increase achieved with the combination of all 3 maneuvers was only 17.4% +/- 16.1%. As a single maneuver, the simulated V was the most effective (11.6% +/- 11.5%). In children, the combination of all 3 maneuvers performed simultaneously produced a mean 65.9% (SD +/- 44.7%) increase in the CSA, which was larger than the increase by all other maneuvers alone or in a single combination (Friedman's test, P < 0.001 and Wilcoxon's test, P < 0.002). As a single maneuver, V produced the most increase (40.4% +/- 32.2%) compared with L compression (14.3% +/- 18.9%) or T position (24.3% +/- 27.1%).

IMPLICATIONS

The combinations of simulated Valsalva, liver compression, and Trendelenburg maneuvers produce the maximal mean increase in the size of the internal jugular vein in infants and young children, with the Valsalva maneuver being the most effective single maneuver. This increase is significant in young children, but negligible in infants.