Postoperative orthostatic intolerance following fast-track unicompartmental knee arthroplasty: incidence and hemodynamics-a prospective observational cohort study.

BACKGROUND: Early postoperative mobilization is essential for early functional recovery but can be inhibited by postoperative orthostatic intolerance (OI). Postoperative OI is common after major surgery, such as total knee arthroplasty (TKA). However, limited data are available after less extensive surgery, such as unicompartmental knee arthroplasty (UKA). We, therefore, investigated the incidence of OI as well as cardiovascular and tissue oxygenation responses during early mobilization after UKA. METHODS: This prospective single-centre observational study included 32 patients undergoing primary UKA. Incidence of OI and cardiovascular and tissue oxygenation responses during mobilization were evaluated preoperatively, at 6 and 24 h after surgery. Perioperative fluid balance, bleeding, surgery duration, postoperative hemoglobin, pain during mobilization and opioid usage were recorded. RESULTS: During mobilization at 6 h after surgery, 4 (14%, 95%CI 4-33%) patients experienced OI; however, no patients terminated the mobilization procedure prematurely. Dizziness and feeling of heat were the most common symptoms. OI was associated with attenuated systolic and mean arterial blood pressure responses in the sitting position (all p < 0.05). At 24 h after surgery, 24 (75%) patients had already been discharged, including three of the four patients with early OI. Only five patients were available for measurements, two of whom experienced OI; one terminated the mobilization procedure due to intolerable symptoms. We observed no statistically significant differences in perioperative fluid balance, bleeding, surgery duration, postoperative hemoglobin, pain, or opioid usage between orthostatic intolerant and tolerant patients. CONCLUSIONS: The incidence of orthostatic intolerance after fast-track unicompartmental knee arthroplasty is low (~ 15%) and is associated with decreased orthostatic pressure responses. Compared to the previously described orthostatic intolerance incidence of ~ 40% following total knee arthroplasty, early orthostatic intolerance is uncommon after unicompartmental knee arthroplasty, suggesting a procedure-specific component. TRIAL REGISTRATION: Prospectively registered at ClinicalTrials.gov; registration number: NCT04195360, registration date: 13.12.2019.

Orthostatic intolerance after acute mild hypovolemia: incidence, pathophysiologic hemodynamics, and heart-rate variability analysis-a prospective observational cohort study.

PURPOSE: Early postoperative mobilization can be hindered by orthostatic intolerance (OI). Postoperative OI has multifactorial pathogenesis, possibly involving both postoperative hypovolemia and autonomic dysfunction. We aimed to investigate the effect of mild acute blood loss from blood donation simulating postoperative hypovolemia, on both autonomic function and OI, thus eliminating confounding perioperative factors such as inflammation, residual anesthesia, pain, and opioids. METHODS: This prospective observational cohort study included 26 blood donors. Continuous electrocardiogram data were collected during mobilization and night sleep, both before and after blood donation. A Valsalva maneuver and a standardized mobilization procedure were performed immediately before and after blood donation, during which cardiovascular and tissue oxygenation variables were continuously measured by LiDCOrapid™ and Massimo Root™, respectively. The incidence of OI, hemodynamic responses during mobilization and Valsalva maneuver, as well as heart rate variability (HRV) responses during mobilization and sleep were compared before and 15 min after blood donation. RESULTS: Prior to blood donation, no donors experienced OI during mobilization. After blood donation, 6/26 (23%; 95% CI, 9 to 44) donors experienced at least one OI symptom. Three out of 26 donors (12%; 95% CI, 2 to 30) terminated the mobilization procedure prematurely because of severe OI symptoms. Cardiovascular and cerebral tissue oxygenation responses were reduced in patients with severe OI. After blood loss, HRV indices of total autonomic power remained unchanged but increased sympathetic and decreased parasympathetic outflow was observed during mobilization, but also during sleep, indicating a prolonged autonomic effect of hypovolemia. CONCLUSION: We describe a specific hypovolemic component of postoperative OI, independent of postoperative autonomic dysfunction, inflammation, opioids, and pain. STUDY REGISTRATION: ClinicalTrials.gov (NCT04499664); registered 5 August 2020.

RéSUMé: OBJECTIF: La mobilisation postopératoire précoce peut être entravée par une intolérance orthostatique (IO). L'IO postopératoire a une pathogenèse multifactorielle, impliquant peut-être à la fois une hypovolémie postopératoire et un dysfonctionnement autonome. Notre objectif était d'étudier l'effet d'une légère perte de sang aiguë due au don de sang simulant une hypovolémie postopératoire, à la fois sur la fonction autonome et sur l'IO, éliminant ainsi les facteurs périopératoires confondants tels que l'inflammation, l'anesthésie résiduelle, la douleur et les opioïdes. MéTHODE: Cette étude de cohorte observationnelle prospective comprenait 26 personnes ayant donné leur sang. Des données d'électrocardiogramme continu ont été recueillies pendant la mobilisation et le sommeil nocturne, avant et après le don de sang. Une manœuvre de Valsalva et une procédure de mobilisation standardisée ont été réalisées immédiatement avant et après le don de sang, au cours desquelles les variables d'oxygénation cardiovasculaire et tissulaire ont été mesurées en continu avec les moniteurs LiDCOrapid™ et Massimo Root™, respectivement. L'incidence d'IO, les réponses hémodynamiques pendant la mobilisation et la manœuvre de Valsalva, ainsi que les réponses de variabilité de la fréquence cardiaque (VFC) pendant la mobilisation et le sommeil ont été comparées avant et 15 minutes après le don de sang. RéSULTATS: Avant le don de sang, aucune personne ayant fait un don de sang n'a ressenti d'IO pendant la mobilisation. Après le don de sang, 6/26 (23 %; IC 95 %, 9 à 44) des donneurs et donneuses ont manifesté au moins un symptôme d'IO. Trois personnes sur 26 (12 %; IC 95 %, 2 à 30) ont interrompu prématurément la procédure de mobilisation en raison de symptômes graves d'IO. Les réponses d'oxygénation des tissus cardiovasculaires et cérébraux ont été réduites chez les personnes atteintes d'IO sévère. Après la perte de sang, les indices de VFC de la puissance totale autonome sont demeurés inchangés, mais une augmentation du flux sympathique et une diminution du flux parasympathique ont été observées pendant la mobilisation, mais également pendant le sommeil, indiquant un effet autonome prolongé de l'hypovolémie. CONCLUSION: Nous décrivons une composante spécifique hypovolémique de l'IO postopératoire, indépendante du dysfonctionnement autonome postopératoire, de l'inflammation, des opioïdes et de la douleur. ENREGISTREMENT DE L'éTUDE: www.ClinicalTrials.gov (NCT04499664); enregistrée le 5 août 2020.

Prevalence and associated factors of postoperative orthostatic intolerance at University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia, 2022: cross sectional study.

BACKGROUND: Postoperative orthostatic intolerance is an inability to maintain an upright position because of symptoms of cerebral hypoperfusion. It is a common problem in the early postoperative period and hinders early mobilization, however, there is limited information about factors associated with it. Thus, the main aim of this study was to determine the prevalence and identify factors associated with postoperative orthostatic intolerance. METHOD: Hospital based cross-sectional study was conducted from April 08 to July 20, 2022, at University of Gondar comprehensive Specialized Hospital. A semi-structured questionnaire containing sociodemographic variables and perioperative factors related to anesthesia and surgery was used for data collection. The presence of postoperative orthostatic intolerance during the first ambulation was evaluated with a standardized symptom checklist which contains symptoms of orthostatic intolerance. Binary logistic regression analysis was performed to assess factors associated with postoperative orthostatic intolerance. In multivariable regression, variables with P-value < 0.05 were considered statistically significant. RESULT: A total of 420 patients were included in this study with a response rate of 99.06%. Postoperative orthostatic intolerance was experienced in 254 (60.5%) participants. Being female (AOR = 2.27; 95% CI = 1.06-4.86), low BMI (AOR = 0.79; 95% CI = 0.71-0.95), ASA II and above (AOR = 3.34; 95% CI = 1.34-8.28), low diastolic blood pressure (AOR = 0.82; 95% CI = 0.88-0.99), general anesthesia (AOR = 3.26, 95% CI = 1.31-8.12), high intraoperative blood lose (AOR = 0.93, 95% CI = 0.88-0.99), high postoperative fluid intake (AOR = 2.09, 95% CI = 1.23-3.55), pain before ambulation (AOR = 1.99, 95% CI = 1.28-3.11) and pain during ambulation (AOR = 1.82, 95% CI = 1.23-2.69) were the significant factors associated with orthostatic intolerance. CONCLUSION: Our study revealed that postoperative orthostatic intolerance was experienced in nearly two-thirds of participants. During the time of ambulation, assessing patients for the presence of orthostatic intolerance is necessary to reduce the adverse effects of postoperative OI. In addition, maintaining preoperative normotension, reducing intraoperative blood loss and optimizing postoperative pain control is recommended to reduce the risk of postoperative orthostatic intolerance.

Orthostatic Intolerance-Type Events Following Hip and Knee Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: Orthostatic intolerance (OI)-type events following hip and knee arthroplasty increase the risk of falls, hospital length of stay, and health-care costs. There is a limited understanding of the incidence of and risk factors for OI-type events in patients during the acute hospital stay. Our aim was to systematically review the incidence of and risk factors for OI-type events during the acute hospital stay following hip and knee arthroplasty. METHODS: A systematic review and meta-analysis of studies that investigated the incidence of and risk factors for OI-type events was undertaken. A comprehensive search was performed in MEDLINE, Embase, and CINAHL from their inception to October 2021. The methodological quality of identified studies was assessed using the modified version of the Quality in Prognosis Studies (QUIPS) tool. RESULTS: Twenty-one studies (14,055 patients) were included. The incidence was 2% to 52% for an OI event, 1% to 46% for orthostatic hypotension, and 0% to 18% for syncope/vasovagal events. Two studies reported female sex, high peak pain levels (>5 out of 10) during mobilization, postoperative use of gabapentin, and the absence of postoperative intravenous dexamethasone as risk factors. There was no consensus on the definition and assessment of an OI-type event. CONCLUSIONS: OI-type events are common during the acute hospital stay following hip and knee arthroplasty, and 4 risk factors have been reported for OI-type events. High-quality prospective cohort studies are required to systematically and reliably determine the incidence of and risk factors for OI-type events. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Orthostatic intolerance after fast-track knee arthroplasty: Incidence and hemodynamic pathophysiology.

BACKGROUND: Early postoperative mobilization can be hindered by orthostatic intolerance (OI) due to failed orthostatic cardiovascular regulation. The underlying mechanisms are not fully understood and specific data after total knee arthroplasty (TKA) are lacking. Therefore, we evaluated the incidence of OI and the cardiovascular response to mobilization in fast-track TKA. METHODS: This prospective observational cohort study included 45 patients scheduled for primary TKA in spinal anesthesia with a multimodal opioid-sparing analgesic regime. OI and the cardiovascular response to sitting and standing were evaluated with a standardized mobilization procedure preoperatively, and at 6 and 24 h postoperatively. Hemodynamic variables were measured non-invasively (LiDCO™ Rapid). Perioperative bleeding, fluid balance, surgery duration, postoperative hemoglobin, opioid use, and pain during mobilization were recorded. RESULTS: Eighteen (44%) and 8 (22%) patients demonstrated OI at 6 and 24 h after surgery, respectively. Four (10%) and 2 (5%) patients experienced severe OI and terminated the mobilization procedure prematurely. Dizziness was the most common OI symptom during mobilization at 6 h. OI was associated with decreased orthostatic responses in systolic, diastolic, mean arterial pressures, and heart rate (all p < .05), while severe OI patients demonstrated impaired diastolic, mean arterial pressures, heart rate, and cardiac output responses (all p < .05). No statistically significant differences in perioperative bleeding, fluid balance, surgery duration, postoperative hemoglobin, pain, or opioid use were observed between orthostatic tolerant and intolerant patients. CONCLUSION: Early postoperative OI is common following fast-track TKA. Pathophysiologic mechanisms include impaired orthostatic cardiovascular responses. The progression to severe OI symptoms appears to be primarily due to inadequate heart rate response.

Orthostatic intolerance: a handicap of aging or physical deconditioning?

Despite several studies that have been investigated physical inactivity and age-related effects on orthostatic tolerance, impaired hemodynamics and postural balance responses to orthostatic stress are incorrectly attributed to aging or sedentarism alone. The isolated effects from aging and sedentarism should be investigated through comparative studies between senior athletes and age-matched controls, and physical activity assessments on aging follow-up studies. On the other hand, bed rest and space flight studies mimic accelerated physical inactivity or disuse, which is not the same physiological decline provoked by aging alone. Thus, the elementary question is: could orthostatic intolerance be attributed to aging or physical inactivity? The main purpose of this review is to provide an overview of possible mechanisms underlying orthostatic tolerance contrasting the paradigm of aging and/or physical inactivity. The key points of this review are the following: (1) to counterpoint all relevant literature on physiological aspects of orthostatic tolerance; (2) to explore the mechanistic aspects underneath the cerebrovascular, cardiorespiratory, and postural determinants of orthostatic tolerance; and (3) examine non-pharmacological interventions with the potential to counterbalance the physical inactivity and aging effects. To date, the orthostatic intolerance cannot be attributed exclusively with aging since physical inactivity plays an important role in postural balance, neurovascular and cardiorespiratory responses to orthostatic stress. These physiological determinates should be interpreted within an integrative approach of orthostatic tolerance, that considers the interdependence between physiological systems in a closed-loop model. Based on this multisystem approach, acute and chronic countermeasures may combat aging and sedentarism effects on orthostatic tolerance.

Prospective Evaluation of Autonomic Dysfunction in Post-Acute Sequela of COVID-19.

BACKGROUND: Patients with post-acute sequela of COVID-19 (PASC) often report symptoms of orthostatic intolerance and autonomic dysfunction. Numerous case reports link postural orthostatic tachycardia syndrome (POTS) to PASC. No prospective analysis has been performed. OBJECTIVES: This study performed head-up tilt table (HUTT) testing in symptomatic patients with PASC to evaluate for orthostatic intolerance suggestive of autonomic dysfunction. METHODS: We performed a prospective, observational evaluation of patients with PASC complaining of poor exertional tolerance, tachycardia with minimal activity or positional change, and palpitations. Exclusion criteria included pregnancy, pre-PASC autonomic dysfunction or syncope, or another potential explanation of PASC symptoms. All subjects underwent HUTT. RESULTS: Twenty-four patients with the described PASC symptoms were included. HUTT was performed a mean of 5.8 ± 3.5 months after symptom onset. Twenty-three of the 24 had orthostatic intolerance on HUTT, with 4 demonstrating POTS, 15 provoked orthostatic intolerance (POI) after nitroglycerin, 3 neurocardiogenic syncope, and 1 orthostatic hypotension. Compared with those with POTS, patients with POI described significantly earlier improvement of symptoms. CONCLUSIONS: This prospective evaluation of HUTT in patients with PASC revealed orthostatic intolerance on HUTT suggestive of autonomic dysfunction in nearly all subjects. Those with POI may be further along the path of clinical recovery than those demonstrating POTS.

The impact of orthostatic intolerance on early ambulation following abdominal surgery in an enhanced recovery programme.

BACKGROUND: The prevalence of orthostatic intolerance on the day of surgery is more than 50% after abdominal surgery. The impact of orthostatic intolerance on ambulation on the day of surgery has been little studied. We investigated orthostatic intolerance and walking ability after colorectal and bariatric surgery in an enhanced recovery programme. METHODS: Eighty-two patients (colorectal: n = 46, bariatric n = 36) were included and analysed in this prospective study. Walk tests for 2 min (2-MWT) and 6 min (6-MWT) were performed before and 24 h after surgery, and 3 h after surgery for 2-MWT. Orthostatic intolerance characterised by presyncopal symptoms when rising was recorded at the same time points. Multivariate binary logistic regressions modelling the probability of orthostatic intolerance and walking inability were performed taking into account potential risk factors. RESULTS: Prevalence of orthostatic intolerance and walking inability was, respectively, 65% and 18% 3-hour after surgery. The day after surgery, patients' performance had greatly improved: approximately 20% of the patients experienced orthostatic intolerance, whilst only 5% of the patients were unable to walk. Adjusted binary logistic regressions demonstrated that age (p = .37), sex (p = .39), BMI (p = .74), duration of anaesthesia (p = .71) and type of surgery (p = .71) did not significantly influence walking ability. CONCLUSION: Our study confirms that orthostatic intolerance was frequent (~ 60%) 3-hour after abdominal surgery but prevented a 2-MWT only in ~20% of patients. No risk factors for orthostatic intolerance and walking inability were evidenced.

Orthostatic intolerance in post-concussion patients.

Orthostatic intolerance (OI) following pediatric concussion is not well understood. Assessing the prevalence of concussion-related OI and how it compares to non-concussion-related OI will improve care for patients suffering with these symptoms. OBJECTIVE: We set out to describe concussion-related OI in adolescence, with particular emphasis on time to recovery and differences from non-concussion-related OI (including male vs. female prevalence). Retrospective chart reviews were completed on post-concussion patients endorsing symptoms of OI. The patients' sex, sport history, previous concussions, time since injury, and recovery time were analyzed and compared between males and females as well as against general OI statistics. Thirty-nine pediatric patients, representing 8.7% of all new patients referred to a specialized concussion clinic over a 13-month interval, were included in the chart review. Mean age of onset was 15.0 ± 2.5 years and 18 (46%) were males. The median times from evaluation to symptom resolution were 120 days. Of 18 patients who completed head-up tilt table testing, 17 (94%) had orthostatic tachycardic response (>40 bpm heart rate increment). Post-concussive OI differs from other orthostatic intolerance etiologies, lacking a strong female predominance and exhibiting a shorter time course to recovery compared to other etiologies of OI (but longer recovery time compared to concussion patients in general). Clinical orthostatic vital signs may not be sensitive for diagnosing orthostatic intolerance in athletes, likely due to higher vagal tone and more efficient skeletal muscle pump.

Chronic Fatigue Syndrome and Cardiovascular Disease: JACC State-of-the-Art Review.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a medically unexplained illness characterized by severe fatigue limiting normal daily activities for at least 6 months accompanied by problems with unrefreshing sleep, exacerbation of symptoms following physical or mental efforts (postexertional malaise [PEM]), and either cognitive reports or physiological evidence of orthostatic intolerance in the form of either orthostatic tachycardia and/or hypocapnia. Although rarely considered to have cardiac dysfunction, ME/CFS patients frequently have reduced stroke volume with a significant inverse relation between cardiac output and PEM severity. Magnetic resonance imaging of ME/CFS patients compared with normal control subjects found significantly reduced stroke, end-systolic, and end-diastolic volumes together with reduced end-diastolic wall mass. Another cardiovascular abnormality is reduced nocturnal blood pressure assessed by 24-hour monitoring. Autonomic dysfunction is also frequently observed with postural orthostatic tachycardia and/or hypocapnia. Two consecutive cardiopulmonary stress tests may provide metabolic data substantiating PEM.

Orthostatic intolerance after bariatric surgery: A systematic review and meta-analysis.

There have been increased reports of orthostatic intolerance post-bariatric surgery. However, the prevalence, pathophysiology and long-term outcomes have not been well described. Therefore, we sought to summarize evidence of orthostatic intolerance after bariatric surgery. We conducted a systematic review using PubMed, Scopus, CINAHL, Cochrane Database of Systematic Reviews and the Cochrane Central Register of Controlled Trials (CENTRAL) to identify relevant articles from the date of inception until 1st April 2020. Study selection, data extraction and quality assessment of the included studies were performed independently by two reviewers. The findings of the included studies were narratively reported. When feasible, a meta-analysis was done to summarize the relevant results. We included 20 studies (n = 19 843 participants) reporting findings of 12 prospective cohort studies, 5 retrospective cohort studies, 2 cross-sectional studies and one randomized controlled trial. The 5-year cumulative incidence of orthostatic intolerance was 4.2% (one study). Common clinical presentations of orthostatic intolerance were lightheadedness, dizziness, syncope and palpitation. The pooled data suggested improvement in overall cardiac autonomic function (sympathetic and parasympathetic) post-bariatric surgery. In addition, a significant systolic blood pressure drop may reflect a reset of the balance between the sympathetic and parasympathetic nervous systems after weight loss in the pooled analysis. Existing literature on orthostatic intolerance post-bariatric surgeries was limited or of low quality, and larger studies are needed to know the true incidence of orthostatic intolerance post-bariatric surgeries and the pathophysiology. We found one study reporting the 5-years cumulative incidence of orthostatic intolerance post-bariatric surgeries as only 4.2%. This could challenge the idea of increased orthostatic intolerance prevalence post-bariatric surgeries. Registration The review protocol was registered at the International Prospective Register of Systemic Reviews PROSPERO (CRD42020170877).

Early Cerebral Hypoperfusion in Patients with Orthostatic Intolerance Without Tachycardia During Head-Up Tilt Test is Independent of Vasovagal Response.

BACKGROUND: Cerebral hypoperfusion before syncope has been shown in patients with chronic orthostatic intolerance (OI) without tachycardia, but it is unknown if an initial decrease of cerebral blood flow velocity (CBFv) could be related to the vasovagal response (VVR) to head-up tilt test (HUTT). OBJECTIVE: The objective of the study was to compare cardiovascular, cerebrovascular, and autonomic variables during HUTT in OI patients with or without a VVR. METHODS: We included 74 subjects (58% female, mean age 33 ± 12 years) who underwent a 30-min HUTT and were divided into three groups: OI with VVR positive (VVR+), OI without VVR negative (VVR-), and asymptomatic healthy subjects with negative HUTT (control group). Cardiovascular, cerebrovascular, and autonomic variables were assessed beat-to-beat during HUTT with a Task Force monitor and a trans-cranial Doppler. Mean values were evaluated at baseline and throughout the first 10 min of tilting. RESULTS: Cardiovascular variables were similar in the three groups. Systolic, diastolic, and mean CBFv were similar in VVR+ and VVR-, but both groups had lower CBFv than the control group. Systolic and diastolic CBFv decreased from baseline since min 1 in VVR+ and VVR- and since min 5 in the control group. The mean CBFv had a significant decrease since min 1 compared to baseline in all groups. Spectral indices of heart rate and blood pressure variability showed a similar autonomic response to HUTT in all groups. CONCLUSION: Patients with chronic OI without tachycardia have early postural cerebral hypoperfusion, regardless of the VVR during HUTT.

Delayed symptoms and orthostatic intolerance following peanut challenge.

BACKGROUND: Clinical reactions to Oral Food Challenge (OFC) in peanut-allergic individuals have been well-characterised, but rates and phenotypes of symptom recurrence beyond the first hour after objective symptoms are less well-characterised. OBJECTIVE: To evaluate the rate of new-onset symptoms occurring at least 1 h after stopping OFC in peanut-allergic children and adults undergoing peanut-OFC. METHODS: We prospectively collected data relating to adverse events following positive reactions at double-blind, placebo-controlled food challenges (DBPCFC) to peanut in children and adults evaluated for eligibility to participate in two clinical trials (NCT02149719, NCT02665793). The trials included people aged 8 to 45 with primary, IgE-mediated peanut allergy at DBPCFC. The challenge protocol included consumption of a light meal 1 h after reaction. RESULTS: A total of 121 participants (64 children, 57 adults) had immediate, objective symptoms at DBPCFC, 25 (17 children, 8 adults) with anaphylaxis. Thirty-three (27%) had progression or recurrence of symptoms ≥ 1 h after objective clinical reaction, of whom 8 developed anaphylaxis. In 23 cases, the onset of new symptoms was associated with consumption of a light meal. In eight cases, symptoms were limited to a symptomatic postural fall in blood pressure noted in preparation for discharge, without any other new features of an allergic reaction. CONCLUSIONS & CLINICAL RELEVANCE: Progressive or new-onset symptoms ≥1 h following initial allergic reaction at OFC are common and can include orthostatic hypotension. Recurrent symptoms may be temporally associated with food consumption.

Orthostatic Intolerance after Bariatric Surgery: a Systematic Review.

Predisposing factors of new-onset orthostatic intolerance (OI) after bariatric surgery (BS) are unknown. The purpose of this study is to summarize current existing data on new-onset OI after BS. Materials and methods were considered for a search of articles that were published by the 30th of July 2020. A systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and in line with the protocol agreed by all authors was conducted. Of the 604 initially identified articles, four studies were found to match the established criteria and were extracted for eligibility. 83.3% were female. Hypertension, type 2 diabetes mellitus, and obstructive sleep apnea syndrome were the most frequently reported comorbidities. Surgical intervention such as revision, conversion, or reversal was not documented in these studies. Awareness of this issue must be raised due to the possibility of reduced quality of life and the risk of syncope.

The Effect of Orthostatic Hypotension Detected Pre-Operatively on Post-Operative Outcome.

BACKGROUND: Exacerbation of or new onset orthostatic hypotension in perioperative patients can occur. There is complex underlying pathophysiology with further derailment likely caused by acute cardiovascular changes associated with surgery. The implications for post-operative recovery are unclear, particularly in frail and older patients. We retrospectively explored patient notes for evidence of post-operative orthostatic intolerance in relation to pre-operative orthostatic hypotension. METHODS: Supine and 1-minute and 3-minute standing blood pressure measures obtained from adult patients before mainly general, orthopedic or uro/gynecology surgery were compared to post-operative outcome, specifically, evidence in patient notes about falls, feeling dizzy/unsteady and/or fearful to stand. Orthostatic hypotension was defined as a 20 mmHg or more and/or 10 mmHg or more fall in systolic and diastolic blood pressure, respectively, within ~3 minutes of standing after lying supine for an electrocardiogram. RESULTS: Whilst all patients included had a 1-minute standing blood pressure assessment (N = 170), 3-minute assessment was performed less commonly (N = 113). Nevertheless, one-quarter (23.5%; N = 40) of 170 patients had pre-operative orthostatic hypotension. This was not clearly explained by cardiac or neurological disease or by common medications, but did occur more frequently in older patients and in those aged 65 years or more with higher clinical frailty scale scores. The COVID-19 pandemic reduced the number of patients progressing to surgery within the planned study timescale (N = 143/170; 84.1%). Nevertheless, patients with orthostatic hypotension stayed longer in hospital post-operatively and were more likely to have an episode of fall, unsteadiness and/or dizziness documented (un-prompted) in their notes. CONCLUSIONS: These data provide further impetus for research into modifiable perioperative risk factors associated with orthostatic hypotension. These risks are not confined to those with a pre-existing dysautonomia diagnosis.

Cardiac autonomic recovery following traditional and augmented remote ischemic preconditioning.

PURPOSE: While the possible ergogenic benefits of remote ischemic preconditioning (RIPC) make it an attractive training modality, the mechanisms of action remain unclear. Alterations in neural tone have been demonstrated in conjunction with circulatory occlusion, yet investigation of the autonomic nervous system following RIPC treatment has received little attention. We sought to characterize alterations in autonomic balance to both RIPC and augmented RIPC (RIPCaug) performed while cycling, using acute and sustained autonomic indices. METHODS: Thirteen participants (8M:5F) recorded baseline waking heart rate variability (HRV) for 5 days prior to treatment. Participants then completed control exercise (CON), RIPC, and RIPCaug interventions in a randomized cross-over design. Cardiovascular measurements were recorded immediately before and after each intervention at rest, and during an orthostatic challenge. Waking HRV was repeated the morning after each intervention. RESULTS: RIPC resulted in acutely reduced resting heart rates (HR) (∆ - 4 ± 6 bpm, P = 0.02) and suppressed HR 30 s following the orthostatic challenge compared to CON (64 ± 10 vs 74 ± 9 bpm, P = 0.003). RIPCaug yielded elevated HRs compared to CON and RIPC prior to (P = 0.003) and during the orthostatic challenge (P = 0.002). RIPCaug reduced LnSDNN (Baseline 4.39 ± 0.27; CON 4.44 ± 0.39; RIPC 4.41 ± 0.34; RIPCaug 4.22 ± 0.29, P = 0.02) and LnHfa power (Baseline 7.82 ± 0.54; CON 7.73 ± 1.11; RIPC 7.89 ± 0.78; RIPCaug 7.23 ± 0.87, P = 0.04) the morning after treatment compared to all other conditions. CONCLUSIONS: Our data suggest that RIPC may influence HR acutely, possibly through a reduction in cardiac sympathetic activity, and that RIPCaug reduces HRV through cardiac vagal withdrawal or increased cardiac sympathetic modulation, with alterations persisting until the following morning. These findings imply a dose-response relationship with potential for optimization of performance.

Risks of adverse events in patients with orthostatic intolerance undergoing surgery with general anesthesia.

INTRODUCTION: Orthostatic intolerance (OI) is a group of disorders characterized by symptoms that occur upon standing and resolve with recumbence. Although well established but not widely recognized, these diagnoses may create uncertainty for clinicians dealing with a patient affected by OI and requiring a surgical procedure. OBJECTIVES: To determine the rate of intra- and postoperative major adverse events in patients with OI undergoing surgery with general anesthesia. METHODS: The study was a retrospective study of patients with orthostatic intolerance who underwent surgery requiring general anesthesia from 1 January 2000 to 31 December 2018. RESULTS: A total 171 patients with OI underwent 190 surgeries. In patients with POTS and orthostatic-induced VVS, there were no major significant adverse events. There was one episode of AVNRT in a patient with POTS and one episode of bradycardia secondary to vasovagal reflex in a patient with orthostatic-induced VVS. Moreover, there were 13 (6.8%) episodes of postoperative hypotension. However, the majority of these episodes were related to bleeding, volume depletion or sepsis. All cases of hypotension responded well to appropriate therapy. In patients with OH, the rate of postoperative major adverse cardiac events was 4.7%, and the 30-day mortality rate was 6.1%. This is not significantly different from the calculated risk for patients without OH. There were no myocardial infarctions or deaths at 30 days in patients with POTS or orthostatic-induced VVS. CONCLUSION: Patients with OI may not experience higher rates of perioperative complications compared with patients without OI syndromes.

Symptom Score: A New Instrument to Assess Orthostatic Intolerance in Children and Adolescents.

OBJECTIVE: To develop an orthostatic intolerance symptom scoring system to assess orthostatic intolerance and then to compare the symptom score among different head-up tilt test responses. METHODS: 272 subjects (5-18 years) presenting with orthostatic intolerance symptoms finished questionnaire and head-up tilt test. According to head-up tilt test hemodynamic responses, the subjects were divided into head-up tilt test negative, vasovagal syncope, and postural tachycardia syndrome groups. RESULTS: We built up a symptom score according to the frequency of dizziness, headache, blurred vision, palpitations, chest discomfort, gastrointestinal symptoms, profuse perspiration, and syncope. The median score in postural tachycardia syndrome subjects was highest. A score of 2.5 for predicting vasovagal syncope yielded a sensitivity of 75.0% and specificity of 50.3%, a score of 5.5 for predicting postural tachycardia syndrome yielded a sensitivity of 69.7% and specificity of 72.0%. Furthermore, the median score in postural tachycardia syndrome subjects was significantly higher than that in head-up tilt test negative subjects with heart rate increment of 30-39 beats/min (P < .01). CONCLUSIONS: This suggests that the symptom score has some predictive value in head-up tilt test results, which can be served as a preliminary assessment instrument.

Screening for Orthostatic Intolerance in Symptomatic Children Presenting for Concussion Care.

Following concussion, children often experience nonspecific symptoms that overlap with those of other common pediatric conditions, including orthostatic intolerance (OI). The primary goal of this study was to evaluate OI in youth presenting for clinical care for concussion and reporting symptoms frequently observed in OI. Eighty-two of 114 patients aged 10 to 22 years endorsed symptoms based on 8 screening questions, and 24 of those 82 patients met criteria for OI based on an active standing test. No screening question generated clinically useful likelihood ratios for predicting OI. The prevalence of OI in this cohort is considerably higher than estimates in the general pediatric population, suggesting a link between concussion and OI. Future work is needed to evaluate the best method of testing for OI, the natural history of OI symptoms in youth with concussion, and the response to intervention in children with both concussion and OI.