Does the stressed patient with chronic fatigue syndrome hyperventilate?

Respiratory dysfunction in persistent somatic symptoms: A systematic review of observational studies

OBJECTIVE

This systematic review aims to analyze the existing literature investigating respiratory functioning in people with Persistent Somatic Symptoms (PSS) compared to healthy controls, to identify patterns of respiratory disturbances by symptom or syndrome, and describe any respiratory outcomes consistent across diagnoses.

METHODS

A systematic review following PRISMA guidelines was conducted. A comprehensive search was carried out across five databases (PubMed (NCBI), PsycArticles (Ovid), Web of Science (Core Collection), Embase, and Scopus) using two customised search strings for persistent somatic symptoms and objective respiratory parameters. Title/abstract screening and data extraction were carried out independently by two reviewers. The modified Newcastle-Ottawa Scale was used for quality assessment of the studies. Studies investigating baseline respiratory functioning in adult patients with PSS compared to healthy controls, using at least one objective respiratory were included.

RESULTS

18 studies met the inclusion criteria for the review, with a pooled sample size of n = 3245. Chronic pain conditions were found to be the most prevalent subset of diagnoses of interest, comprising six of the studies. 10 studies included measures of lung capacity, flow and/or volume, nine studies reported measures of ventilation, and four studies investigated respiratory muscle functioning. 13 of the included studies reported significant differences in at least one objective respiratory measure between groups (at rest). Scores on self-reported measures of dysnpea and breathlessness were higher in patients compared to healthy controls, while objective respiratory outcomes were varied.

CONCLUSION

The current systematic review is consistent with previous literature suggesting more pronounced experiences of breathlessness in patients with PSS, and significant disparities between reported dyspnea and objective respiratory outcomes. Research investigating the uncoupling between subjective and objective respiratory outcomes is needed to understand the mechanisms behind breathing disturbances in PSS.

Physiological assessment of orthostatic intolerance in chronic fatigue syndrome

BACKGROUND

Orthostatic intolerance-OI is common in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-ME/CFS. We used a 10-min passive vertical lean test as orthostatic challenge-OC and measured changes in vitals and end tidal CO2 (eTCO2). An abnormal physiologic response to OC was identified in 60% of the 63 patients evaluated from one to three times over several years. Hypocapnia, either resting or induced by OC, was the most frequent abnormality, followed by postural orthostatic tachycardia.

OBJECTIVE

Evaluate the physiologic response of patients with ME/CFS to a standardized OC.

DESIGN

Respiratory and heart rate, blood pressure and eTCO2 were recorded twice at the end of 10-min supine rest and then every minute during the 10-min lean. Hypocapnia was eTCO2 ≤ 32 mmHg. Orthostatic tachycardia was heart rate increase ≥ 30 beats per minute compared with resting or ≥ 120 BPM. Orthostatic hypotension was decreased systolic pressure ≥ 20 mmHg from baseline. Tachypnea was respiratory rate of  ≥ 20 breaths per minute-either supine or leaning. Questionnaire data on symptom severity, quality of life and mood were collected at visit #2.

PATIENTS

63 consecutive patients fulfilling the 1994 case definition for CFS underwent lean testing at first visit and then annually at visit 2 (n = 48) and 3 (n = 29).

MEASURES

Supine hypocapnia; orthostatic tachycardia, hypocapnia or hypotension.

RESULTS

The majority of ME/CFS patients (60.3%, 38/63) had an abnormality detected during a lean test at any visit (51%, 50% and 45% at visits 1, 2 and 3, respectively). Hypocapnia at rest or induced by OC was more common and more likely to persist than postural orthostatic tachycardia. Anxiety scores did not differ between those with and without hypocapnia.

CONCLUSIONS

The 10-min lean test is useful in evaluation of OI in patients with ME/CFS. The most frequent abnormality, hypocapnia, would be missed without capnography.

Use of Cardiopulmonary Stress Testing for Patients With Unexplained Dyspnea Post-Coronavirus Disease

Objectives

The authors used cardiopulmonary exercise testing (CPET) to define unexplained dyspnea in patients with post-acute sequelae of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection (PASC). We assessed participants for criteria to diagnose myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Background

Approximately 20% of patients who recover from coronavirus disease (COVID) remain symptomatic. This syndrome is named PASC. Its etiology is unclear. Dyspnea is a frequent symptom.

Methods

The authors performed CPET and symptom assessment for ME/CFS in 41 patients with PASC 8.9 ± 3.3 months after COVID. All patients had normal pulmonary function tests, chest X-ray, and chest computed tomography scans. Peak oxygen consumption (peak VO₂), slope of minute ventilation to CO₂ production (VE/VCO₂ slope), and end tidal pressure of CO₂ (PetCO₂) were measured. Ventilatory patterns were reviewed with dysfunctional breathing defined as rapid erratic breathing.

Results

Eighteen men and 23 women (average age: 45 ± 13 years) were studied. Left ventricular ejection fraction was 59% ± 9%. Peak VO₂ averaged 20.3 ± 7 mL/kg/min (77% ± 21% predicted VO₂). VE/VCO₂ slope was 30 ± 7. PetCO₂ at rest was 33.5 ± 4.5 mm Hg. Twenty-four patients (58.5%) had a peak VO₂ <80% predicted. All patients with peak VO₂ <80% had a circulatory limitation to exercise. Fifteen of 17 patients with normal peak VO₂ had ventilatory abnormalities including peak respiratory rate >55 (n = 3) or dysfunctional breathing (n = 12). For the whole cohort, 88% of patients (n = 36) had ventilatory abnormalities with dysfunctional breathing (n = 26), increased VE/VCO₂ (n = 17), and/or hypocapnia PetCO₂ <35 (n = 25). Nineteen patients (46%) met criteria for ME/CFS.

Conclusions

Circulatory impairment, abnormal ventilatory pattern, and ME/CFS are common in patients with PASC. The dysfunctional breathing, resting hypocapnia, and ME/CFS may contribute to symptoms. CPET is a valuable tool to assess these patients.

Hyperventilation in patients with chronic fatigue syndrome: the role of coping strategies

Hyperventilation has been suggested as a concomitant and possible maintaining factor that may contribute to the symptom pattern of chronic fatigue syndrome (CFS). Because patients accepting the illness and trying to live with it seem to have a better prognosis than patients chronically fighting it, we investigated breathing behavior during different coping response sets towards the illness in patients with CFS (N=30, CDC criteria). Patients imagined a relaxation script (baseline), a script describing a coping response of hostile resistance, and a script depicting acceptance of the illness and its (future) consequences. During each imagery trial, end-tidal PCO2 (Handheld Capnograph, Oridion) was measured. After each trial, patients filled out a symptom checklist. Results showed low resting values of PetCO2 overall, while only imagery of hostile resistance triggered a decrease and deficient recovery of PetCO2. Also, more hyperventilation complaints and complaints of other origin were reported during hostile resistance imagery compared with acceptance and relaxation. In conclusion, hostile resistance seems to trigger both physiological and symptom perception processes contributing to the clinical picture of CFS.

Psychological profile and ventilatory response to inspiratory resistive loading

The purpose of this study was to explore the contribution of psychological state to both the ventilatory response and the intensity of dyspnea experienced after the addition of small inspiratory loads to breathing. We hypothesized that patients with either a specific psychiatric diagnosis or a specific psychological trait will associate a greater degree of dyspnea with a loaded breathing task than will control subjects. To insure the inclusion of persons with relevant psychological profiles, we recruited both subjects enrolled in the Chronic Fatigue Center and normal control subjects. In all, 52 subjects inspired first through a small (1.34 cm H(2)O/L/s) and second through a moderate (3.54 cm H(2)O/L/s) inspiratory resistive load (IRL). Ventilation was monitored throughout the 5-min sessions. Dyspnea was quantified with the Borg scale at specified times during the protocol. Standard psychological tests were administered. We found that subjects could be divided into two groups. One, the "responders," reported Borg scores higher than those of the second, or "nonresponder" group, at all times during the protocol. By contrast, there was no difference between groups with respect to ventilation. Responders had higher scores on tests of depression (the Center for Epidemiological Study depression scale) than did nonresponders. We conclude that the variability observed in subjective responses to IRL is explained, in part, by differences in psychological state.

Presence of hyperventilation in patients with asthma-like symptoms but negative asthma test responses: provocation with voluntary hyperventilation and mental stress

BACKGROUND

A group of patients reporting asthma-like symptoms but with negative asthma tests has been identified.

OBJECTIVE

The objective of this study was to determine whether hyperventilation might explain these symptoms and whether the tests could be used as diagnostic tools.

METHODS

A hyperventilation provocation test (HVPT), a mental stress test, and the Word Color Conflict Test (WCCT) were performed on 10 patients with asthma-like symptoms, 10 patients with asthma, and 10 healthy subjects. End-tidal PCO 2 (PETCO2) was recorded 10 minutes after the HVPT and during the WCCT. Blood pressure, heart rate, and respiratory rate were also studied. The Nijmegen symptom questionnaire was used in the assessment of symptoms.

RESULTS

After the HVPT, the PETCO2 values recovered most slowly in the study group, the difference being significant compared with the healthy group (P <.01). During the WCCT, the study group had the lowest PETCO2 values at the 10- and 15-minute measurements, the difference again being significant compared with the healthy group (P <.05). The study group more often experienced symptoms before the test than the group with asthma (P <.05) and the healthy group (P <.001). The study group recognized significantly more symptoms previously experienced during the HVPT than the group with asthma (P <.05) and the healthy group (P <.01) and during the WCCT than the healthy group (P <.05). The study group showed a negative correlation between the PETCO2 level and the number of symptoms after the HVPT at 8 (r = -0-72; P <.05) and 10 minutes (r = -0.76; P <.05) and after the WCCT (r = -0.59; P <.05). Blood pressure, heart rate, and respiratory rate showed small differences between the groups.

CONCLUSION

Patients with asthma-like symptoms may experience hyperventilation when provoked. Mental stress might be 1 trigger factor. The HVPT and WCCT can be used as diagnostic instruments.