ArticlePloS one2018
Hypocapnic cerebral hypoperfusion: A biomarker of orthostatic intolerance.
Article in PloS one, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT04271878 (Hypercapnia and Orthostatic Tolerance in Postural Orthostatic Tachycardia Syndrome), which is not on this map. Cited by 28 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Hypercapnia and Orthostatic Tolerance in Postural Orthostatic Tachycardia Syndrome
Who cites it
28 citing papers in PubMed, 2 syntheses or guidelines pooled it.
- Mapping cerebral blood flow in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and orthostatic intolerance: insights from a systematic review.Journal of translational medicine · 2025Pooled it
- Is there a relationship between hypocapnia and tachycardia in postural orthostatic tachycardia syndrome (POTS)? A systematic review.Clinical autonomic research : official journal of the Clinical Autonomic Research Society · 2023Pooled it
- Article
- Assessment of internal consistency reliability and concurrent validity of PROMISJournal of patient-reported outcomes · 2026Article
- Stroke volume reduction impairs cerebrovascular regulation through ETCOClinical autonomic research : official journal of the Clinical Autonomic Research Society · 2026Article
- Hypermobile Ehlers-Danlos Syndrome: Cerebrovascular, Autonomic and Neuropathic Features.American journal of medicine open · 2025Article
- Role of Central Sensitization Syndrome in Patients With Autonomic Symptoms.Neurology. Clinical practice · 2025Article
- Cerebral Blood Flow in Orthostatic Intolerance.Journal of the American Heart Association · 2025Review
- Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky Syndrome.Frontiers in neurology · 2025Article
- Cerebral blood flow and end-tidal CONeurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology · 2024Article
- Physiological Targets for Orthostatic Hypotension: Improving Nonpharmacological Interventions in Patients with Orthostatic Cerebral Hypoperfusion.Applied psychophysiology and biofeedback · 2024Article
- Reduced Stroke Volume and Brain Perfusion Drive Postural Hyperventilation in Postural Orthostatic Tachycardia Syndrome.JACC. Basic to translational science · 2024Article
- Is it time to move beyond blood pressure and heart rate during head-up tilt testing?Clinical autonomic research : official journal of the Clinical Autonomic Research Society · 2024Article
- Mismatch between subjective and objective dysautonomia.Scientific reports · 2024Article
- Orthostatic intolerance with tachycardia (postural tachycardia syndrome) and without (hypocapnic cerebral hypoperfusion) represent a spectrum of the same disorder.Frontiers in neurology · 2024Article
- Worsening Symptoms Is Associated with Larger Cerebral Blood Flow Abnormalities during Tilt-Testing in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).Medicina (Kaunas, Lithuania) · 2023Article
- Comparison of a 20 degree and 70 degree tilt test in adolescent myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients.Frontiers in pediatrics · 2023Article
- Long-Haul COVID Patients: Prevalence of POTS Are Reduced but Cerebral Blood Flow Abnormalities Remain Abnormal with Longer Disease Duration.Healthcare (Basel, Switzerland) · 2022Article
- Orthostatic Intolerance in Long-Haul COVID after SARS-CoV-2: A Case-Control Comparison with Post-EBV and Insidious-Onset Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients.Healthcare (Basel, Switzerland) · 2022Article
- Qpack-a Python package for QASAT-quantitative scale for grading cerebral blood flow, autonomic testing, and skin biopsies.Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology · 2022Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
1 author.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The objective of the study was to identify markers of hypocapnic cerebral hypoperfusion (HYCH) in patients with orthostatic intolerance (OI) without tachycardia and without orthostatic hypotension. This single center, retrospective study included OI patients referred for autonomic evaluation with the 10 min tilt test. Heart rate, end-tidal CO2 (ET-CO2), blood pressure, and cerebral blood flow velocity (CBFv) from middle cerebral artery were monitored. HYCH was defined by: (1) Symptoms of OI; (2) Orthostatic hypocapnia (low ET-CO2); (3) Abnormal decline in orthostatic CBFv due to hypocapnia; 4) Absence of tachycardia, orthostatic hypotension, or other causes of low CBFv or hypocapnia. Sixteen subjects met HYCH criteria (15/1 women/men, age 38.5±8.0 years) and were matched by age and gender to postural tachycardia patients (POTS, n = 16) and healthy controls (n = 16). During the tilt, CBFv decreased more in HYCH (-22.4±7.7%, p<0.0001) and POTS (-19.0±10.3%, p<0.0001) compared to controls (-3.0±5.0%). Orthostatic ET-CO2 was lower in HYCH (26.4±4.2 (mmHg), p<0.0001) and POTS (28.6±4.3, p<0.0001) compared to controls (36.9 ± 2.1 mmHg). Orthostatic heart rate was normal in HYCH (89.0±10.9 (BPM), p<0.08) and controls (80.8 ±11.2), but was higher in POTS (123.7±11.2, p<0.0001). Blood pressure was normal and similar in all groups. It is concluded that both HYCH and POTS patients have comparable decrease in CBFv which is due to vasoconstrictive effect of hypocapnia. Blood flow velocity monitoring can provide an objective biomarker for HYCH in OI patients without tachycardia.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.