Major Depressive Disorder and Chronic Fatigue Syndrome Show Characteristic Heart Rate Variability Profiles Reflecting Autonomic Dysregulations: Differentiation by Linear Discriminant Analysis.

Major depressive disorder (MDD) and chronic fatigue syndrome (CFS) have overlapping symptoms, and differentiation is important to administer the proper treatment. The present study aimed to assess the usefulness of heart rate variability (HRV) indices. Frequency-domain HRV indices, including high-frequency (HF) and low-frequency (LF) components, their sum (LF+HF), and their ratio (LF/HF), were measured in a three-behavioral-state paradigm composed of initial rest (Rest), task load (Task), and post-task rest (After) periods to examine autonomic regulation. It was found that HF was low at Rest in both disorders, but was lower in MDD than in CFS. LF and LF+HF at Rest were low only in MDD. Attenuated responses of LF, HF, LF+HF, and LF/HF to task load and an excessive increase in HF at After were found in both disorders. The results indicate that an overall HRV reduction at Rest may support a diagnosis of MDD. HF reduction was found in CFS, but with a lesser severity. Response disturbances of HRV to Task were observed in both disorders, and would suggest the presence of CFS when the baseline HRV has not been reduced. Linear discriminant analysis using HRV indices was able to differentiate MDD from CFS, with a sensitivity and specificity of 91.8% and 100%, respectively. HRV indices in MDD and CFS show both common and different profiles, and can be useful for the differential diagnosis.

Is the Effect of the COVID-19 Vaccine on Heart Rate Variability Permanent?

Background and Objectives: The risk of autonomic dysfunction with COVID-19 vaccines used worldwide in the COVID-19 pandemic remains a topic of debate. Heart rate variability has a number of parameters that can be used to assess autonomic nervous system dynamics. The aim of this study was to investigate the effect of a COVID-19 vaccine (Pfizer-BioNTech) on heart rate variability and autonomic nervous system parameters, and the duration of the effect. Materials and Methods: A total of 75 healthy individuals who visited an outpatient clinic to receive the COVID-19 vaccination were included in this prospective observational study. Heart rate variability parameters were measured before vaccination and on days 2 and 10 after vaccination. SDNN, rMSSD and pNN50 values were evaluated for time series analyses, and LF, HF, and LF/HV values for frequency-dependent analyses. Results: The SDNN and rMSDD values declined significantly on day 2 after vaccination, while the pNN50 and LF/HF values increased significantly on day 10. The values at pre-vaccination and at day 10 were comparable. The pNN50 and LF/HF values declined significantly on day 2 and increased significantly on day 10. The values at pre-vaccination and at day 10 were comparable. Conclusions: This study showed that the decline in HRV observed with COVID-19 vaccination was temporary, and that the Pfizer-BioNTech COVID-19 vaccination did not cause permanent autonomic dysfunction.

Identification of major depression patients using machine learning models based on heart rate variability during sleep stages for pre-hospital screening.

With the COVID-19 pandemic causing challenges in hospital admissions globally, the role of home health monitoring in aiding the diagnosis of mental health disorders has become increasingly important. This paper proposes an interpretable machine learning solution to optimise initial screening for major depressive disorder (MDD) in both male and female patients. The data is from the Stanford Technical Analysis and Sleep Genome Study (STAGES). We analyzed 5-min short-term electrocardiogram (ECG) signals during nighttime sleep stages of 40 MDD patients and 40 healthy controls, with a 1:1 gender ratio. After preprocessing, we calculated the time-frequency parameters of heart rate variability (HRV) based on the ECG signals and used common machine learning algorithms for classification, along with feature importance analysis for global decision analysis. Ultimately, the Bayesian optimised extremely randomized trees classifier (BO-ERTC) showed the best performance on this dataset (accuracy 86.32%, specificity 86.49%, sensitivity 85.85%, F1-score 0.86). By using feature importance analysis on the cases confirmed by BO-ERTC, we found that gender is one of the most important factors affecting the prediction of the model, which should not be overlooked in our assisted diagnosis. This method can be embedded in portable ECG monitoring systems and is consistent with the literature results.

Parasympathetic autonomic dysfunction is more often evidenced than sympathetic autonomic dysfunction in fluctuating and polymorphic symptoms of "long-COVID" patients.

Several disabling symptoms potentially related to dysautonomia have been reported in "long-COVID" patients. Unfortunately, these symptoms are often nonspecific, and autonomic nervous system explorations are rarely performed in these patients. This study aimed to evaluate prospectively a cohort of long-COVID patients presenting severe disabling and non-relapsing symptoms of potential dysautonomia and to identify sensitive tests. Autonomic function was assessed by clinical examination, the Schirmer test; sudomotor evaluation, orthostatic blood pressure (BP) variation, 24-h ambulatory BP monitoring for sympathetic evaluation, and heart rate variation during orthostatism, deep breathing and Valsalva maneuvers for parasympathetic evaluation. Test results were considered abnormal if they reached the lower thresholds defined in publications and in our department. We also compared mean values for autonomic function tests between patients and age-matched controls. Sixteen patients (median age 37 years [31-43 years], 15 women) were included in this study and referred 14.5 months (median) [12.0-16.5 months] after initial infection. Nine had at least one positive SARS-CoV-2 RT-PCR or serology result. Symptoms after SARS-CoV-2 infection were severe, fluctuating and disabling with effort intolerance. Six patients (37.5%) had one or several abnormal test results, affecting the parasympathetic cardiac function in five of them (31%). Mean Valsalva score was significantly lower in patients than in controls. In this cohort of severely disabled long-COVID patients, 37.5% of them had at least one abnormal test result showing a possible contribution of dysautonomia to these nonspecific symptoms. Interestingly, mean values of the Valsalva test were significantly lower in patients than in control subjects, suggesting that normal values thresholds might not be appropriate in this population.

Racial Differences in Blood Pressure and Autonomic Recovery Following Acute Supramaximal Exercise in Women.

Despite the growing popularity of high-intensity anaerobic exercise, little is known about the acute effects of this form of exercise on cardiovascular hemodynamics or autonomic modulation, which might provide insight into the individual assessment of responses to training load. The purpose of this study was to compare blood pressure and autonomic recovery following repeated bouts of acute supramaximal exercise in Black and White women. A convenience sample of twelve White and eight Black young, healthy women were recruited for this study and completed two consecutive bouts of supramaximal exercise on the cycle ergometer with 30 min of recovery in between. Brachial and central aortic blood pressures were assessed by tonometry (SphygmoCor Xcel) at rest and 15-min and 30-min following each exercise bout. Central aortic blood pressure was estimated using brachial pressure waveforms and customized software. Autonomic modulation was measured in a subset of ten participants by heart-rate variability and baroreflex sensitivity. Brachial mean arterial pressure and diastolic blood pressure were significantly higher in Blacks compared to Whites across time (race effect, p = 0.043 and p = 0.049, respectively). Very-low-frequency and low-frequency bands of heart rate variability, which are associated with sympathovagal balance and vasomotor tone, were 22.5% and 24.9% lower, respectively, in Blacks compared to Whites (race effect, p = 0.045 and p = 0.006, respectively). In conclusion, the preliminary findings of racial differences in blood pressure and autonomic recovery following supramaximal exercise warrant further investigations of tailored exercise prescriptions for Blacks and Whites.

Accuracy of Self-Injection Locking Radar System for Vital Signs Detection During the COVID-19 Pandemic at a Hospital in Taiwan: Measuring Vital Signs Accurately with SIL Radar for Hospital Healthcare.

BACKGROUND Self-injection locking (SIL) radar uses continuous-wave radar and an injection-locked oscillator-based frequency discriminator that receives and demodulates radar signals remotely to monitor vital signs. This study aimed to compare SIL radar with traditional electrocardiogram (ECG) measurements to monitor respiratory rate (RR) and heartbeat rate (HR) during the COVID-19 pandemic at a single hospital in Taiwan. MATERIAL AND METHODS We recruited 31 hospital staff members (16 males and 15 females) for respiratory rates (RR) and heartbeat rates (HR) detection. Data acquisition with the SIL radar and traditional ECG was performed simultaneously, and the accuracy of the measurements was evaluated using Bland-Altman analysis. RESULTS To analyze the results, participates were divided into 2 groups (individual subject and multiple subjects) by gender (male and female), or 4 groups (underweight, normal weight, overweight, and obesity) by body mass index (BMI). The results were analyzed using mean bias errors (MBE) and limits of agreement (LOA) with a 95% confidence interval. Bland-Altman plots were utilized to illustrate the difference between the SIL radar and ECG monitor. In all BMI groups, results of RR were more accurate than HR, with a smaller MBE. Furthermore, RR and HR measurements of the male groups were more accurate than those of the female groups. CONCLUSIONS We demonstrated that non-contact SIL radar could be used to accurately measure HR and RR for hospital healthcare during the COVID-19 pandemic.

Pre-pandemic autonomic function as a predictor of the COVID clinical course in young adults.

Long coronavirus disease (COVID) is emerging as a common clinical entity in the current era. Autonomic dysfunction is one of the frequently reported post-COVID complications. We hypothesize a bi-directional relationship between the autonomic function and the COVID course. This postulation has been inadequately addressed in the literature. A retrospective cohort (pre and post-comparison) study was conducted on 30 young adults whose pre-COVID autonomic function test results were available. They were divided into case and control groups based on whether they tested reverse transcription polymerase chain reaction positive for COVID-19. Autonomic function tests were performed in both the case and control groups. COVID infection in healthy young adults shifts the sympatho-vagal balance from the pre-disease state. Postural orthostatic tachycardia syndrome was present in 35% of the COVID-affected group. COVID course parameters were found to be associated with parasympathetic reactivity and the baroreflex function. Baseline autonomic function (parasympathetic reactivity represented by Δ heart rate changes during deep breathing and 30:15 ratio during lying-to-standing test) was also associated with the COVID course, the post-COVID symptoms and the post-COVID autonomic function profile. Additionally, multiple regression analysis found that the baseline parasympathetic reactivity was a very important determinant of the clinical course of COVID, the post-COVID symptoms and the post-COVID autonomic profile. Sympatho-vagal balance shifts to parasympathetic withdrawal with sympathetic predominance due to COVID infection in healthy young adults. There is a bi-directional relationship between the autonomic function and the COVID course.

Surgical management of tension pneumomediastinum in mechanically ventilated coronavirus disease 2019 patients.

INTRODUCTION: Tension pneumomediastinum is an increasingly common condition since the COVID-19 pandemic's onset. It is a life-threatening complication with severe hemodynamic instability that is refractory to catecholamines. Surgical decompression with drainage is the key point of treatment. Various surgical procedures are reported in the literature, but no cohesive approach has yet been developed. AIM: The aim was to present the available options for surgical treatment of tension pneumomediastinum, as well as the post-interventional results. MATERIALS AND METHODS: Nine cervical mediastinotomies were performed on intensive-care unit (ICU) patients who developed a tension pneumomediastinum during mechanical ventilation. The age and sex of patients, surgical complications, pre- and post-intervention basic hemodynamic parameters, as well as oxygen saturation levels, were recorded and analyzed. RESULTS: The mean age of patients was 62±16 years (6 males and 3 females). No postoperative surgical complications were recorded. The average preoperative systolic blood pressure was 91±12 mmHg, the heart rate was 104±8 bpm, and the oxygen saturation level was 89±6%, while the short-term postoperative values changed to 105±6 mmHg, 101±4 bpm, and 94±5%, respectively. There was no long-term survival benefit, with a mortality rate of 100%. CONCLUSIONS: Cervical mediastinotomy is the operative method of choice in the presence of tension pneumomediastinum allowing an effective decompression of the mediastinal structures and improving the condition of the affected patients without improving the survival rate.

Resting heart rate is a population-level biomarker of cardiorespiratory fitness: The Fenland Study.

INTRODUCTION: Few large studies have evaluated the relationship between resting heart rate (RHR) and cardiorespiratory fitness. Here we examine cross-sectional and longitudinal relationships between RHR and fitness, explore factors that influence these relationships, and demonstrate the utility of RHR for remote population monitoring. METHODS: In cross-sectional analyses (The UK Fenland Study: 5,722 women, 5,143 men, aged 29-65y), we measured RHR (beats per min, bpm) while seated, supine, and during sleep. Fitness was estimated as maximal oxygen consumption (ml⋅min-1⋅kg-1) from an exercise test. Associations between RHR and fitness were evaluated while adjusting for age, sex, adiposity, and physical activity. In longitudinal analyses (6,589 participant subsample), we re-assessed RHR and fitness after a median of 6 years and evaluated the association between within-person change in RHR and fitness. During the coronavirus disease-2019 pandemic, we used a smartphone application to remotely and serially measure RHR (1,914 participant subsample, August 2020 to April 2021) and examined differences in RHR dynamics by pre-pandemic fitness level. RESULTS: Mean RHR while seated, supine, and during sleep was 67, 64, and 57 bpm. Age-adjusted associations (beta coefficients) between RHR and fitness were -0.26, -0.29, and -0.21 ml⋅kg-1⋅beat-1 in women and -0.27, -0.31, and -0.19 ml⋅kg-1⋅beat-1 in men. Adjustment for adiposity and physical activity attenuated the RHR-to-fitness relationship by 10% and 50%, respectively. Longitudinally, a 1-bpm increase in supine RHR was associated with a 0.23 ml⋅min-1⋅kg-1 decrease in fitness. During the pandemic, RHR increased in those with low pre-pandemic fitness but was stable in others. CONCLUSIONS: RHR is a valid population-level biomarker of cardiorespiratory fitness. Physical activity and adiposity attenuate the relationship between RHR and fitness.

Autonomic dysfunction in COVID-19 patients receiving mechanical ventilation: A cross-sectional study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) can damage cardiac tissue by increasing troponin levels and inducing arrhythmias, myocarditis, and acute coronary syndrome. OBJECTIVES: To analyze the impact of COVID-19 on cardiac autonomic control in mechanically ventilated intensive care unit (ICU) patients. DESIGN AND SETTING: This cross-sectional analytical study of ICU patients of both sexes receiving mechanical ventilation was conducted in a tertiary hospital. METHODS: Patients were divided into COVID-19-positive (COVID(+)) and COVID-19-negative (COVID(-)) groups. Clinical data were collected and heart rate variability (HRV) records obtained using a heart rate monitor. RESULTS: The study sample comprised 82 subjects: 36 (44%) in the COVID(-) group (58.3% female; median age, 64.5 years) and 46 (56%) in the COVID(+) group (39.1% females; median age, 57.5 years). The HRV indices were lower than the reference values. An intergroup comparison identified no statistically significant differences in the mean normal-to-normal (NN) interval, standard deviation of the NN interval, or root mean square of successive differences in NN intervals. The COVID(+) group had an increased low frequency (P = 0.05), reduced high frequency (P = 0.045), and increased low frequency/high frequency (LF/HF) ratio (P = 0.048). There was a weak positive correlation between LF/HF and length of stay in the COVID(+) group. CONCLUSION: Patients who received mechanical ventilation had lower overall HRV indices. COVID(+) patients who received mechanical ventilation had lower vagal HRV components. These findings likely indicate clinical applicability, as autonomic control impairments are associated with a greater risk of cardiac death.

A Nonrandomized Trial of the Effects of Passive Simulated Jogging on Short-Term Heart Rate Variability in Type 2 Diabetic Subjects.

Background: Diabetes mellitus has reached global epidemic proportions, with type 2 diabetes (T2DM) comprising more than 90% of all subjects with diabetes. Cardiovascular autonomic neuropathy (CAN) frequently occurs in T2DM. Heart rate variability (HRV) reflects a neural balance between the sympathetic and parasympathetic autonomic nervous systems (ANS) and a marker of CAN. Reduced HRV has been shown in T2DM and improved by physical activity and exercise. External addition of pulses to the circulation, as accomplished by a passive simulated jogging device (JD), restores HRV in nondiseased sedentary subjects after a single session. We hypothesized that application of JD for a longer period (7 days) might improve HRV in T2DM participants. Methods: We performed a nonrandomized study on ten T2DM subjects (age range 44-73 yrs) who were recruited and asked to use a physical activity intervention, a passive simulated jogging device (JD) for 7 days. JD moves the feet in a repetitive and alternating manner; the upward movement of the pedal is followed by a downward movement of the forefoot tapping against a semirigid bumper to simulate the tapping of feet against the ground during jogging. Heart rate variability (HRV) analysis was performed using an electrocardiogram in each subject in seated posture on day 1 (baseline, BL), after seven days of JD (JD7), and seven days after discontinuation of JD (Post-JD). Time domain variables were computed, viz., standard deviation of all normal RR intervals (SDNN), standard deviation of the delta of all RR intervals (SDΔNN), and the square root of the mean of the sum of the squares of differences between adjacent RR intervals (RMSSD). Frequency domain measures were determined using a standard Fast Fourier spectral analysis, as well as the parameters of the Poincaré plots (SD1 and SD2). Results: Seven days of JD significantly increased SDNN, SDΔNN, RMSSD, and both SD1 and SD2 from baseline values. The latter parameters remained increased Post-JD. JD did not modify the frequency domain measures of HRV. Conclusion: A passive simulated jogging device increased the time domain and Poincaré variables of HRV in T2DM. This intervention provided effortless physical activity as a novel method to harness the beneficial effects of passive physical activity for improving HRV in T2DM subjects.

Postural Orthostatic Tachycardia Syndrome After COVID-19: A Systematic Review of Therapeutic Interventions.

ABSTRACT: Postural orthostatic tachycardia syndrome (POTS) is a clinical syndrome of inappropriate increase in heart rate on standing that has been recently also associated with Coronavirus Disease 2019 (COVID-19) as part of the postacute sequelae of COVID-19 (PASC) or long-COVID. We herein aimed to systematically review reported cases of POTS after COVID-19 and determine the characteristics of the subjects, the diagnostic approach used, and the treatment strategies. We searched the literature according to the following criteria: (1) diagnosis of POTS according to standard definition; (2) timely association with a probable or definite diagnosis of COVID-19; and (3) a description of the individual subject(s). We identified 21 reports meeting criteria between March 2020 and September 2022, including 68 subjects (51 females and 17 males, 3:1 ratio) with a mean age of 34 ± 12 years, with reports deriving from the United States, Norway, Sweden, Israel, Ireland, United Kingdom, Singapore, and Japan. Most cases had mild COVID-19 symptoms. The most common POTS symptoms were palpitations, chest pain, lightheadedness, and debilitating fatigue. The diagnosis was established by means of head-up tilt table or active stand test. Nonpharmacologic treatments (fluids, sodium intake, and compression stockings) were virtually always used, but largely ineffective. Subjects received different treatments, the most common being beta-adrenergic blockers (ie, propranolol), mineral corticosteroids (ie, fludrocortisone), midodrine, and ivabradine. Symptoms tended to improve over time, but most patients remained symptomatic for several months. In conclusion, POTS after COVID-19 is a clinical condition affecting young individuals, and disproportionately young women, occurring as part of PASC-long-COVID, often debilitating, which can be easily diagnosed with a thorough clinical assessment and measuring changes in orthostatic heart rate and blood pressure. POTS after COVID-19 seems to be poorly responsive to nonpharmacological treatments but with symptoms improving with pharmacological interventions. Given the limited data available, additional research is urgently needed with respect to its epidemiology, pathophysiology, and treatments.

Atrial Fibrillation Occurring During Acute Hospitalization: A Scientific Statement From the American Heart Association.

Acute atrial fibrillation is defined as atrial fibrillation detected in the setting of acute care or acute illness; atrial fibrillation may be detected or managed for the first time during acute hospitalization for another condition. Atrial fibrillation after cardiothoracic surgery is a distinct type of acute atrial fibrillation. Acute atrial fibrillation is associated with high risk of long-term atrial fibrillation recurrence, warranting clinical attention during acute hospitalization and over long-term follow-up. A framework of substrates and triggers can be useful for evaluating and managing acute atrial fibrillation. Acute management requires a multipronged approach with interdisciplinary care collaboration, tailoring treatments to the patient's underlying substrate and acute condition. Key components of acute management include identification and treatment of triggers, selection and implementation of rate/rhythm control, and management of anticoagulation. Acute rate or rhythm control strategy should be individualized with consideration of the patient's capacity to tolerate rapid rates or atrioventricular dyssynchrony, and the patient's ability to tolerate the risk of the therapeutic strategy. Given the high risks of atrial fibrillation recurrence in patients with acute atrial fibrillation, clinical follow-up and heart rhythm monitoring are warranted. Long-term management is guided by patient substrate, with implications for intensity of heart rhythm monitoring, anticoagulation, and considerations for rhythm management strategies. Overall management of acute atrial fibrillation addresses substrates and triggers. The 3As of acute management are acute triggers, atrial fibrillation rate/rhythm management, and anticoagulation. The 2As and 2Ms of long-term management include monitoring of heart rhythm and modification of lifestyle and risk factors, in addition to considerations for atrial fibrillation rate/rhythm management and anticoagulation. Several gaps in knowledge related to acute atrial fibrillation exist and warrant future research.

Management of Psychiatric Conditions in Patients With Comorbid Postural Orthostatic Tachycardia Syndrome: A Literature Review and Case Vignette.

Importance: Disorders of the autonomic nervous system are relatively common and have a significant impact on quality of life, offer very subtle diagnostic clues, and often mimic other disease processes, including certain psychiatric disorders. Pharmacologic treatment for psychiatric conditions in this group of patients can also be complicated by the pathophysiology of the various syndromes. Postural orthostatic tachycardia syndrome (POTS) is the final common pathway of a heterogenous group of underlying disorders that display similar characteristics.Observations: The current literature regarding the association between POTS and psychiatric conditions was reviewed. The literature showed an increased prevalence of mild/moderate depression and sleep disturbance in this population. Also, when psychiatric disorders occur in patients with POTS, clinicians may face challenges with regard to selecting appropriate psychopharmacologic interventions.Conclusions and Relevance: This review provides an evidence-based approach to treating common psychiatric conditions in those who suffer from POTS, with a particular emphasis on side effects that may worsen the associated symptoms. A list of the classes of psychopharmacologic treatment with a focus on adverse effects on heart rate and blood pressure is included, as is a case vignette of a patient with complex comorbid psychiatric conditions. It is of significant value to highlight the complexities associated with POTS; to raise awareness of the disorder, particularly in the context of psychiatric comorbidities; and to disseminate evidence-based information to aid clinicians in making informed medication choices with their patients.

Continuous monitoring is superior to manual measurements in detecting vital sign deviations in patients with COVID-19.

BACKGROUND: Patients admitted to the emergency care setting with COVID-19-infection can suffer from sudden clinical deterioration, but the extent of deviating vital signs in this group is still unclear. Wireless technology monitors patient vital signs continuously and might detect deviations earlier than intermittent measurements. The aim of this study was to determine frequency and duration of vital sign deviations using continuous monitoring compared to manual measurements. A secondary analysis was to compare deviations in patients admitted to ICU or having fatal outcome vs. those that were not. METHODS: Two wireless sensors continuously monitored (CM) respiratory rate (RR), heart rate (HR), and peripheral arterial oxygen saturation (SpO2 ). Frequency and duration of vital sign deviations were compared with point measurements performed by clinical staff according to regional guidelines, the National Early Warning Score (NEWS). RESULTS: SpO2 < 92% for more than 60 min was detected in 92% of the patients with CM vs. 40% with NEWS (p < .00001). RR > 24 breaths per minute for more than 5 min were detected in 70% with CM vs. 33% using NEWS (p = .0001). HR ≥ 111 for more than 60 min was seen in 51% with CM and 22% with NEWS (p = .0002). Patients admitted to ICU or having fatal outcome had longer durations of RR > 24 brpm (p = .01), RR > 21 brpm (p = .01), SpO2 < 80% (p = .01), and SpO2 < 85% (p = .02) compared to patients that were not. CONCLUSION: Episodes of desaturation and tachypnea in hospitalized patients with COVID-19 infection are common and often not detected by routine measurements.

Assessing capacities and resilience of health services during the COVID-19 pandemic: Lessons learned from use of rapid key informant surveys.

This article is part of the Research Topic: 'Health Systems Recovery in the Context of COVID-19 and Protracted Conflict.' Problem: Many countries lacked rapid and nimble data systems to track health service capacities to respond to COVID-19. They struggled to assess and monitor rapidly evolving service disruptions, health workforce capacities, health products availability, community needs and perspectives, and mitigation responses to maintain essential health services. Method: Building on established methodologies, the World Health Organization developed a suite of methods and tools to support countries to rapidly fill data gaps and guide decision-making during COVID-19. The tools included: (1) a national "pulse" survey on service disruptions and bottlenecks; (2) a phone-based facility survey on frontline service capacities; and (3) a phone-based community survey on demand-side challenges and health needs. Use: Three national pulse surveys revealed persisting service disruptions throughout 2020-2021 (97 countries responded to all three rounds). Results guided mitigation strategies and operational plans at country level, and informed investments and delivery of essential supplies at global level. Facility and community surveys in 22 countries found similar disruptions and limited frontline service capacities at a more granular level. Findings informed key actions to improve service delivery and responsiveness from local to national levels. Lessons learned: The rapid key informant surveys provided a low-resource way to collect action-oriented health services data to inform response and recovery from local to global levels. The approach fostered country ownership, stronger data capacities, and integration into operational planning. The surveys are being evaluated to inform integration into country data systems to bolster routine health services monitoring and serve as health services alert functions for the future.

Autonomic heart rate modulation in patients with coronavirus disease 2019 in mechanical ventilation.

BACKGROUND: Patients with coronavirus disease 2019 on automatic mechanical ventilation have greater heart rate modulation with greater parasympathetic modulation. OBJECTIVE: To analyze the autonomic modulation of heart rate in critically ill patients with coronavirus disease 2019 on invasive mechanical ventilation. METHODS: A cross-section study was carried out with 36 individuals divided into two groups. The control group included patients of both genders, in orotracheal intubation with invasive mechanical ventilation under controlled assisted mode, hospitalized in the intensive care unit for another 24 h. In the non-COVID group, patients diagnosed with coronavirus disease 2019 in the same condition mentioned in the control group. RESULTS: There was a significant increase in heart rate variability (standard deviation of all normal RR intervals recorded at an interval of time; p=0.001; triangular interpolation histogram of RR intervals; p=0.048; and SD2; p=0.014) in the coronavirus disease group compared to the non-COVID group. Successively, the parameters that demonstrate parasympathetic modulation are shown to be higher in the group of patients with coronavirus disease 2019 (root mean square of the square of differences between adjacent normal RR intervals in an interval of time; p<0.001; pNN50; p<0.001; SD1; p=0.002; and high frequency; p=0.022). CONCLUSIONS: There was a greater autonomic modulation of heart rate with a greater parasympathetic modulation in patients with coronavirus disease 2019 on mechanical ventilation.

Inverse association between blood pressure and pulse oximetry accuracy: an observational study in patients with suspected or confirmed COVID-19 infection.

BACKGROUND: Pulse oximeters are a standard non-invasive tool to measure blood oxygen levels, and are used in multiple healthcare settings. It is important to understand the factors affecting their accuracy to be able to use them optimally and safely. This analysis aimed to explore the association of the measurement error of pulse oximeters with systolic BP, diastolic BP and heart rate (HR) within ranges of values commonly observed in clinical practice. METHODS: The study design was a retrospective observational study of all patients admitted to a large teaching hospital with suspected or confirmed COVID-19 infection from February 2020 to December 2021. Data on systolic and diastolic BPs and HR levels were available from the same time period as the pulse oximetry measurements. RESULTS: Data were available for 3420 patients with 5927 observations of blood oxygen saturations as measured by pulse oximetry and ABG sampling within 30 min. The difference in oxygen saturation using the paired pulse oximetry and arterial oxygen saturation difference measurements was inversely associated with systolic BP, increasing by 0.02% with each mm Hg decrease in systolic BP (95% CI 0.00% to 0.03%) over a range of 80-180 mm Hg. Inverse associations were also observed between the error for oxygen saturation as measured by pulse oximetry and with both diastolic BP (+0.03%; 95% CI 0.00% to 0.05%) and HR (+0.04%; 95% CI 0.02% to 0.06% for each unit decrease in the HR). CONCLUSIONS: Care needs to be taken in interpreting pulse oximetry measurements in patients with lower systolic and diastolic BPs, and HRs, as oxygen saturation is overestimated as BP and HR decrease. Confirmation of the oxygen saturation with an ABG may be appropriate in some clinical scenarios.

Association of Heart Rate Variability with Pulmonary Function Impairment and Symptomatology Post-COVID-19 Hospitalization.

The persistence of symptoms beyond three months after COVID-19 infection, often referred to as post-COVID-19 condition (PCC), is commonly experienced. It is hypothesized that PCC results from autonomic dysfunction with decreased vagal nerve activity, which can be indexed by low heart rate variability (HRV). The aim of this study was to assess the association of HRV upon admission with pulmonary function impairment and the number of reported symptoms beyond three months after initial hospitalization for COVID-19 between February and December 2020. Follow-up took place three to five months after discharge and included pulmonary function tests and the assessment of persistent symptoms. HRV analysis was performed on one 10 s electrocardiogram obtained upon admission. Analyses were performed using multivariable and multinomial logistic regression models. Among 171 patients who received follow-up, and with an electrocardiogram at admission, decreased diffusion capacity of the lung for carbon monoxide (DLCO) (41%) was most frequently found. After a median of 119 days (IQR 101-141), 81% of the participants reported at least one symptom. HRV was not associated with pulmonary function impairment or persistent symptoms three to five months after hospitalization for COVID-19.