Dynamic cerebral autoregulation is preserved during orthostasis and intrathoracic pressure regulation in healthy subjects: A pilot study

Resistance breathing may restore cardiac output (CO) and cerebral blood flow (CBF) during hypovolemia. We assessed CBF and cerebral autoregulation (CA) during tilt, resistance breathing, and paced breathing in 10 healthy subjects. Blood velocities in the internal carotid artery (ICA), middle cerebral arteries (MCA, four subjects), and aorta were measured by Doppler ultrasound in 30° and 60° semi-recumbent positions. ICA blood flow and CO were calculated. Arterial blood pressure (ABP, Finometer), and end-tidal CO2 (ETCO2) were recorded. ICA blood flow response was assessed by mixed-models regression analysis. The synchronization index (SI) for the variable pairs ABP-ICA blood velocity, ABP-MCA velocities in 0.005-0.08 Hz frequency interval was calculated as a measure of CA. Passive tilting from 30° to 60° resulted in 12% decrease in CO (p = 0.001); ICA blood flow tended to fall (p = 0.04); Resistance breathing restored CO and ICA blood flow despite a 10% ETCO2 drop. ETCO2 and CO contributed to ICA blood flow variance (adjusted R2: 0.9, p < 0.0001). The median SI was low (<0.2) indicating intact CA, confirmed by surrogate date testing. The peak SI was transiently elevated during resistance breathing in the 60° position. Resistance breathing may transiently reduce CA efficiency. Paced breathing did not restore CO or ICA blood flow.

The Diagnosis of Granulomatosis With Polyangiitis When Serology and Biopsies are Negative

Objective

Granulomatosis with polyangiitis (GPA) is a potentially fatal condition which often manifests in the head and neck. Currently, diagnosis relies on antineutrophil cytoplasmic autoantibody (c-ANCA) serology and mucosal or renal biopsy. However, a significant proportion of patients with GPA limited to the head and neck are seronegative and biopsy negative. This study evaluates the role of clinical diagnosis of GPA in the absence of positive laboratory findings.

Study Design

Case series with chart review.

Setting

Academic Tertiary Medical Center.

Methods

This was a retrospective review of 143 patients treated in an outpatient otolaryngology clinic at a tertiary care hospital for known or suspected GPA from 1998 to 2021. Presenting symptoms, C-ANCA status at initial presentation, biopsy results, long-term serology results, and time to initiation of treatment were analyzed.

Results

Twenty-six of 143 (18.2%) patients were seronegative; only 3 of these patients (12%) had positive biopsies. Seventeen (73.9%) of these patients presented with nasal and sinus disease and 12 (52.2%) presented with airway involvement. Only 4 (17.4%) patients had renal involvement. Delay in treatment of patients with negative laboratory workup ranged from 0 months to 11 years. All patients who were seronegative and/or biopsy negative at presentation responded clinically to immunosuppressive therapy.

Conclusion

GPA cases are often limited to the upper respiratory tract, making diagnosis difficult, particularly in seronegative patients. These results suggest that, when GPA is suspected, despite negative serology, the diagnosis of GPA should be made on clinical grounds, and empiric therapy encouraged to prevent delay in treatment.

Nebulized isotonic saline improves voice production in Sjögren's syndrome

OBJECTIVE

This study examined the effects of a topical vocal fold hydration treatment on voice production over time.

STUDY DESIGN

Prospective, longitudinal, within-subjects A (baseline), B (treatment), A (withdrawal/reversal), B (treatment) experimental design.

METHODS

Eight individuals with primary Sjögren's syndrome (SS), an autoimmune disease causing laryngeal dryness, completed an 8-week A-B-A-B experiment. Participants performed twice-daily audio recordings of connected speech and sustained vowels and then rated vocal effort, mouth dryness, and throat dryness. Two-week treatment phases introduced twice-daily 9-mL doses of nebulized isotonic saline (0.9% Na(+)Cl(-)). Voice handicap and patient-based measures of SS disease severity were collected before and after each 2-week phase. Connected speech and sustained vowels were analyzed using the Cepstral Spectral Index of Dysphonia (CSID). Acoustic and patient-based ratings during each baseline and treatment phase were analyzed and compared.

RESULTS

Baseline CSID and patient-based ratings were in the mild-to-moderate range. CSID measures of voice severity improved by approximately 20% with nebulized saline treatment and worsened during treatment withdrawal. Posttreatment CSID values fell within the normal-to-mild range. Similar patterns were observed in patient-based ratings of vocal effort and dryness. CSID values and patient-based ratings correlated significantly (P < .05).

CONCLUSION

Nebulized isotonic saline improves voice production based on acoustic and patient-based ratings of voice severity. Future work should optimize topical vocal fold hydration treatment formulations, dose, and delivery methodologies for various patient populations. This study lays the groundwork for future topical vocal fold hydration treatment development to manage and possibly prevent dehydration-related voice disorders.

LEVEL OF EVIDENCE

2b.

Dysfunctional arteriovenous anastomoses in hands of systemic sclerosis patients with digital ulcers

OBJECTIVES

Previous studies indicate that the arteriovenous anastomoses (AVAs) and the arterioles with the nutritive flow are involved in the pathophysiologic process disturbing hand blood flow in systemic sclerosis (SSc). However, impact of different part of the microvascular system involved in digital ulcers (DU) is not well known. Here, we aimed to assess the vasomotor activity of the AVAs in the hands of patients with and without DU in SSc.

METHODS

Simultaneous recordings were made of laser Doppler flux in the finger pulp and thenar eminence, together with ipsilateral radial artery blood velocity and mean arterial blood pressure (MAP) in 22 non-smoking SSc patients and 13 aged-matched healthy controls.

RESULTS

AVA responses in the finger pulp to spontaneous vasoconstrictor nerve impulses were abolished in 64% of the SSc patients. Correlation and cross-spectra analysis showed positive correlation between blood flow changes and MAP changes, indicating a passive vascular bed in the SSc finger pulp with blood flow variations depending on short-term variability in MAP. Dysfunctional AVAs were identified in all the patients with a history of DU (n=8), while none of the patients with normal AVA function had episodes of DU (n=8) (p= 0.017).

CONCLUSIONS

We found that in SSc patients with DU there is a dysfunction of the AVAs of the finger pulp. This proof-of-concept study supports the notion that AVA dysfunction may play a critical role in SSc related DU. AVA dysfunction may be a part of autonomic dysfunction in SSc.

Hypothermia makes cerebral resistance index a poor prognostic tool in encephalopathic newborns

BACKGROUND

Severe neonatal encephalopathy (NE) of hypoxic-ischaemic origin may cause death or life-long disability. Acute encephalopathy may also affect cerebrovascular control. Pourcelot's cerebrovascular resistance index (RI) ≤0.55 was predictive of poor outcome in normothermic NE infants. Recent studies have questioned its predictive power during therapeutic hypothermia (HT).

OBJECTIVE

To assess the predictive power of RI during HT and after rewarming.

METHODS

45 infants with NE treated with HT for 72 h had their RI calculated during early (median 11 h) and late (median 62 h) cooling and after rewarming (median 89 h). Poor outcome was defined as death or abnormalities on day 10 magnetic resonance imaging shown to predict severe neuromotor disability.

RESULTS

RI ≤0.55 during cooling did not differentiate between good and poor outcome (late cooling, p = 0.08), but was powerful after rewarming (p = 0.004). RI ≤0.55 predicted true poor outcome in 43% (95% confidence interval (CI): 12, 80) during late cooling and in 100% (95% CI: 31, 100) after rewarming. RI >0.55 predicted good outcome in 86% (95% CI: 69, 95) during late cooling and in 89% (95% CI: 74, 96) after rewarming.

CONCLUSIONS

Low RI is not predictive of poor outcome during HT in NE infants, but regains the predictive power seen in normothermic infants after rewarming.

Respiratory variations in pulmonary and systemic blood flow in healthy humans

AIM

Cardiovascular oscillations are tightly coupled to respiration. Respiratory sinus arrhythmia (RSA) is an important part of heart rate variability with unknown function. Stroke volumes from the right (r-SV) and left (l-SV) side of the heart are assumed to vary differently with respiration, but have not previously been recorded non-invasively and simultaneously in humans. The present study introduces an improved technique for capturing respiratory variations in r-SV.

METHODS

Six young volunteers were investigated during spontaneous and metronome-paced breathing in the left lateral decubitus position. Heart rate (HR, from ECG), l-SV (from finger blood arterial pressure curve) and r-SV (pulsed ultrasound Doppler) were recorded. Left and right cardiac outputs (l-CO and r-CO) were calculated beat by beat from HR, l-SV and r-SV. Respiratory variations in cardiovascular variables and phase angles were estimated by spectral analysis at respiratory frequency (0.15-0.40 Hz).

RESULTS

The amplitude of respiratory variations in l-CO was 17% of r-CO (94% CI (6%, 35%), P=0.03). The amplitude of the respiratory variations in l-SV was not different from r-SV (74%, 94% CI (50%, 127%) non-significant). Increases in HR and r-SV were in phase with inspiration, while l-SV decreased during inspiration.

CONCLUSION

The amplitude of respiratory variations in l-CO is significantly smaller than in r-CO. Respiratory variations in HR and in l-SV are in inverse phase; thus, RSA buffers respiratory variations in l-SV. RSA plays an important role in reducing oscillations in systemic blood flow resulting from respiratory changes in venous return.

Nebulized isotonic saline versus water following a laryngeal desiccation challenge in classically trained sopranos

PURPOSE

To examine the effects of nebulized isotonic saline (IS) versus sterile water (SW) on self-perceived phonatory effort (PPE) and phonation threshold pressure (PTP) following a surface laryngeal dehydration challenge in classically trained sopranos.

METHOD

In a double-blind, within-subject crossover design, 34 sopranos breathed dry air (relative humidity < 1%) transorally for 15 min and then nebulized 3 mL of IS or SW, or experienced a no-treatment control condition over 3 consecutive weeks. PPE and PTP were measured every 15 min from baseline through 2 hr postdesiccation.

RESULTS

PPE increased significantly following the laryngeal desiccation challenge in all 3 treatment conditions (p < .01). After nebulization, PPE returned to baseline for the IS condition only. For the SW and control conditions, PPE remained above baseline during the 2 hr after desiccation. No statistically significant changes in PTP following laryngeal desiccation were observed, although values for the IS condition remained below baseline for nearly 2 hr after nebulization. PPE and PTP were not significantly correlated.

CONCLUSIONS

Following a laryngeal surface dehydration challenge, classically trained sopranos reported increased vocal effort that persisted for at least 2 hr. Compared with SW, nebulized IS showed promise as an effective way to remediate the adverse, self-perceived effects of laryngeal desiccation.

Stroke volume decreases during mild dynamic and static exercise in supine humans

AIM

The contributions of cardiac output (CO) and total peripheral resistance to changes in arterial blood pressure are debated and differ between dynamic and static exercise. We studied the role stroke volume (SV) has in mild supine exercise.

METHODS

We investigated 10 healthy, supine volunteers by continuous measurement of heart rate (HR), mean arterial blood pressure, SV (ultrasound Doppler) and femoral beat volume (ultrasound Doppler) during both dynamic mild leg exercise and static forearm exercise. This made it possible to study CO, femoral flow (FF) and both total and femoral peripheral resistance beat-by-beat.

RESULTS

During a countdown period immediately prior to exercise, HR and mean arterial pressure increased, while SV decreased. During mild supine exercise, SV decreased by 5-8%, and most of this was explained by increased mean arterial pressure. Dynamic leg exercise doubled femoral beat volume, while static hand grip decreased femoral beat volume by 18%. FF is tightly regulated according to metabolic demand during both dynamic leg exercise and static forearm exercise.

CONCLUSION

Our three major findings are, firstly, that SV decreases during both dynamic and static mild supine exercise due to an increase in mean arterial pressure. Secondly, femoral beat volume decreases during static hand grip, but FF is unchanged due to the increase in HR. Finally, anticipatory responses to exercise are apparent prior to both dynamic and static exercise. SV changes contribute to CO changes and should be included in studies of central haemodynamics during exercise.

The effects of three nebulized osmotic agents in the dry larynx

PURPOSE

This investigation examined the effects of nebulized hypertonic saline, isotonic saline (IS), and sterile (hypotonic) water on phonation threshold pressure (PTP) and self-perceived phonatory effort (PPE) following a surface laryngeal dehydration challenge.

METHOD

In a double-blind, randomized experimental trial, 60 vocally healthy women (n = 15 per group) underwent a laryngeal desiccation challenge involving oral breathing for 15 min using medical-grade dry air (RH<1%). Three of the four groups then received nebulized isotonic saline (0.9% NaCl), hypertonic saline (7% NaCl), or sterile (hypotonic) water, respectively; the 4th group served as a nontreatment control. PTP and PPE were estimated for high-pitched productions at baseline, immediately postdesiccation, and at 5, 20, 35, and 50 min postnebulization.

RESULTS

PTP increased significantly for all groups following the desiccation challenge. PTP values were, on average, 0.5 cm H(2)O greater immediately postdesiccation versus baseline. In contrast, PTP values did not change significantly following the administration of nebulized treatments, although a temporary trend toward a reduction in PTP was observed for the IS group. Unexpectedly, PPE ratings decreased significantly after the desiccation challenge. In general, PPE ratings were poorly correlated with PTP measures.

CONCLUSION

A laryngeal desiccation challenge (i.e., temporary exposure to extremely low relative humidity while breathing transorally) significantly increased PTP. Although interesting trends emerged, none of the nebulized treatments significantly enhanced recovery from the negative effects of desiccation on PTP. In light of very low correlations between PTP and PPE, serious questions are raised regarding presumed associations between these measures.

Respiratory sinus arrhythmia: opposite effects on systolic and mean arterial pressure in supine humans

1. Are arterial blood pressure fluctuations buffered or reinforced by respiratory sinus arrhythmia (RSA)? There is still considerable debate about this simple question. Different results have been obtained, triggering a discussion as to whether or not the baroreflexes are responsible for RSA. We suspected that the measurements of different aspects of arterial pressure (mean arterial pressure (MAP) and systolic pressure (SP)) can explain the conflicting results. 2. Simultaneous recordings of beat-to-beat MAP, SP, left cardiac stroke volume (SV, pulsed ultrasound Doppler), heart rate (HR) and respiration (RE) were obtained in 10 healthy young adults during spontaneous respiration. In order to eliminate HR variations at respiratory frequency we used propranolol and atropine administration in the supine and tilted positions. Respiration-synchronous variation in the recorded variables was quantified by spectral analysis of the recordings of each of these variables, and the phase relations between them were determined by cross-spectral analysis. 3. MAP fluctuations increased after removing heart rate variations in both supine and tilted position, whereas SP fluctuations decreased in the supine position and increased in the head-up tilted position. 4. RSA buffers respiration-synchronous fluctuations in MAP in both positions. However, fluctuations in SP were reinforced by RSA in the supine and buffered in the tilted position.

Acid-fast-positive Legionella pneumophila: a possible pitfall in the cytologic diagnosis of mycobacterial infection in pulmonary specimens

The acid-fast stain is commonly used in the rapid cytologic assessment of bronchoalveolar lavage (BAL) fluid to detect pulmonary mycobacterial infections, particularly in immunocompromised patients. The identification of acid-fast, rod-shaped organisms may be taken as presumptive evidence of such an infection, in the appropriate clinical setting. However, this determination is made less specific by the occasional acid-fast positivity of microorganisms other than mycobacteria. We report on the occurrence of a fatal pneumonia caused by acid-fast positive Legionella pneumophila detected by BAL. This is a potential pitfall in the rapid diagnosis of pulmonary mycobacterial infections.