The effects of body weight status on orthostatic intolerance and predisposition to noncardiac syncope

Development and Validation of a Novel Predictive Model for the Early Differentiation of Cardiac and Non-Cardiac Syncope

Background

The diagnosis of cardiac syncope remains a challenge. This study sought to develop and validate a diagnostic model for the early identification of individuals likely to have a cardiac cause.

Methods

877 syncope patients with a determined cause were retrospectively enrolled at a tertiary heart center. They were randomly divided into the training set and validation set at a 7:3 ratio. We analyzed the demographic information, medical history, laboratory tests, electrocardiogram, and echocardiogram by the least absolute shrinkage and selection operator (LASSO) regression for selection of key features. Then a multivariable logistic regression analysis was performed to identify independent predictors and construct a diagnostic model. The receiver operating characteristic curves, area under the curve (AUC), calibration curves, and decision curve analysis were used to evaluate the predictive accuracy and clinical value of this nomogram.

Results

Five independent predictors for cardiac syncope were selected: BMI (OR 1.088; 95% CI 1.022-1.158; P =0.008), chest symptoms preceding syncope (OR 5.251; 95% CI 3.326-8.288; P <0.001), logarithmic NT-proBNP (OR 1.463; 95% CI 1.240-1.727; P <0.001), left ventricular ejection fraction (OR 0.940; 95% CI 0.908-0.973; P <0.001), and abnormal electrocardiogram (OR 6.171; 95% CI 3.966-9.600; P <0.001). Subsequently, a nomogram based on a multivariate logistic regression model was developed and validated, yielding AUC of 0.873 (95% CI 0.845-0.902) and 0.856 (95% CI 0.809-0.903), respectively. The calibration curves showcased the nomogram's reasonable calibration, and the decision curve analysis demonstrated good clinical utility.

Conclusion

A diagnostic tool providing individualized probability predictions for cardiac syncope was developed and validated, which may potentially serve as an effective tool to facilitate early identification of such patients.

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.

Prevalence and factors associated with vasovagal reaction among whole blood donors in hospital Universiti Sains Malaysia

Adverse donor reactions (ADR) are common to occur during the blood donation process. The most common is vasovagal reactions (VVR) and it cause negative impact in the donor return rate. The aim of this study is to determine the prevalence of VVR among blood donors and to study its associated factors, at Hospital University Sains Malaysia (USM). This retrospective case-control study was conducted from June 2018, until June 2021. Data was extracted from the blood bank database system and from donor adverse reaction form. Donors who developed adverse donor reactions were chosen and without VVR were chosen at random as controls. A total of 159 donors, out of 35 134 donors were reported to have VVR which resulted in an overall prevalence of 0.45 %. Dizziness or mild VVR were the most frequently observed adverse reactions, accounting for approximately 87/159 (54.7 %) of all adverse reactions. Multiple logistic regression (MLR) analysis showed VVR were significantly associated with age, female gender, first-time donor, and 450 ml volume of blood collected. The prevalence of vasovagal reactions among blood donors in this study was low which was similar to a few previous studies. Although it was low, still it is very important to reduce risks to a minimum so that the donor return rate could be maintained. The information regarding its associated factors can be used to identify high-risk donors to prevent the incidence in the future.

İnsülin Duyarlılığı ve Vücut Kitle İndeksinin Ortostatik İntolerans Üzerine Etkileri

Amaç: Çalışmanın amacı insülin duyarlılığı ve antropometrik ölçümlerin ortostatik intolerans sendromları üzerindeki etkilerini değerlendirmektir. Yöntem: Retrospektif bir çalışmadır. 7-18 yaş arası senkop öyküsü ile başvuran hastalarda insülin duyarlılık indeksleri hesaplandı ve antropometrik ölçümlerine değerlendirildi. Hastalar head-up tilt test sonuçlarına göre test pozitif ve test negatif olarak gruplandırıldı. Ayrıca tilt testi pozitif olan hastalar vazodepresör vazovagal senkop (VVS), kardiyoinhibitör VVS, mikst VVS ve postural ortostatik taşikardi sendromu olmak üzere dört alt gruba ayrıldı. Bulgular: Çalışmaya toplam 509 hasta dahil edildi. Yaş ortalaması 13,45 ± 2,82 yıldı ve %64,4'ü kızdı. Tilt testi 214 hastada pozitif, 295 hastada negatifti. Tilt testi sonuçları ile 173 hastaya VVS ve 41 hastaya (%19) POTS tanısı konuldu. İnsülin duyarlılık indekslerine göre gruplar arasında istatistiksel olarak anlamlı fark yoktu. Antropometrik ölçümlerde boy, boy standart deviasyonu, vücut kitle indeksi (VKİ) standart deviasyonu ve VKİ persentili (sırasıyla p=0,008, p=0,02, p=0,036, p=0,03) açısından iki grup arasında anlamlı farklılık gözlendi. Sonuç: Çalışmamızda özellikle genç kızlarda düşük VKİ ve uzun boylu olmak vazovagal senkop ataklarına zemin hazırlayan faktörler iken, insülin duyarlılık indeksleri ile pozitif head-up tilt test sonucu arasında ilişki bulunmadı. Tekrarlayan senkoplara neden olan faktörlere ışık tutarak uygun tedavinin sağlanması hastaların yaşam kalitelerine katkı sağlayabilir.

Gastrocnemius Muscle Contraction and Its Role in Orthostatic Anti-Gravity Adjustment – The Effects of Body Mass Index

BACKGROUND: Obesity is a global concern with severe detrimental health and economic effect. Body mass index (BMI) is an inexpensive, non-invasive indicator for different diseases, and associated with abnormal weight. AIM: The aim of the study was to investigate the relationship between BMI and the contraction of gastrocnemius muscle (GM) and its possible role in peripheral muscle pump activity and pathogenesis of orthostatic intolerance. METHODS: One hundred and four volunteers (63 women and 41 men, mean age 39 ± 14 years) were divided into three subgroups according to their BMI values (with normal weight, overweight, and obesity). Changes in the transverse diameter and pennation angle of GM at rest and during maximal active plantar flexion (MAPF) were measured with multimodal ultrasound imaging. An active orthostatic test was performed and changes in systemic blood pressure and heart rate in supine position and active standing on the 1st, 5th, and 10th min were monitored. The results were statistically processed with alternative, variational, and correlational analysis. RESULTS: Patients with abnormal BMI were significantly older and had higher anthropometrical parameters compared to the subgroup with normal weight. They showed a significantly larger diameter and pennation angles at rest and during maximal active plantar flexion of GM bilaterally, which was more pronounced for the dominant right leg. However, the amount of changes in the GM diameter and pennation angles was similar in the different subgroups. CONCLUSION: The study showed that BMI affects predominantly the initial values of GM parameters at rest and MAPF without influence on its antigravity contractility associated with active straightening.

Differential Diagnosis Between Psychogenic Pseudosyncope and Vasovagal Syncope in Children: A Quantitative Scoring Model Based on Clinical Manifestations

The study was designed to explore a clinical manifestation-based quantitative scoring model to assist the differentiation between psychogenic pseudosyncope (PPS) and vasovagal syncope (VVS) in children. In this retrospective case-control study, the training set included 233 pediatric patients aged 5–17 years (183 children with VVS and 50 with PPS) and the validation set consisted of another 138 patients aged 5–15 years (100 children with VVS and 38 with PPS). In the training set study, the demographic characteristics and clinical presentation of patients were compared between PPS and VVS. The independent variables were analyzed by binary logistic regression, and the score for each variable was given according to the approximate values of odds ratio (OR) to develop a scoring model for distinguishing PPS and VVS. The cut-off scores and area under the curve (AUC) for differentiating PPS and VVS cases were calculated using receiver operating characteristic (ROC) curve. Then, the ability of the scoring model to differentiate PPS from VVS was validated by the true clinical diagnosis of PPS and VVS in the validation set. In the training set, there were 7 variables with significant differences between the PPS and VVS groups, including duration of loss of consciousness (DLOC) (p &lt; 0.01), daily frequency of attacks (p &lt; 0.01), BMI (p &lt; 0.01), 24-h average HR (p &lt; 0.01), upright posture (p &lt; 0.01), family history of syncope (p &lt; 0.05) and precursors (p &lt; 0.01). The binary regression analysis showed that upright posture, DLOC, daily frequency of attacks, and BMI were independent variables to distinguish between PPS and VVS. Based on the OR values of each independent variable, a score of 5 as the cut-off point for differentiating PPS from VVS yielded the sensitivity and specificity of 92.0% and 90.7%, respectively, and the AUC value was 0.965 (95% confidence interval: 0.945–0.986, p &lt; 0.01). The sensitivity, specificity, and accuracy of this scoring model in the external validation set to distinguish PPS from VVS were 73.7%, 93.0%, and 87.7%, respectively. Therefore, the clinical manifestation-based scoring model is a simple and efficient measure to distinguish between PPS and VVS.

Time in range, as an emerging metric of glycemic control, is associated with orthostatic blood pressure changes in type 2 diabetes

AIMS

To exlpore whether time in range(TIR) was associated with orthostatic blood pressure(BP) changes in type 2 diabetes(T2DM).

METHODS

A total of 342 T2DM patients were recruited. TIR was defined as the time percentage spent within the target range(3.9-10.0 mmol/L). Orthostatic hypotension(OH) and orthostatic hypertension(OHT) were defined as a decrease or an increase of at least 20 mmHg in SBP and/or 10 mmHg in DBP after standing for 3 min.

RESULTS

Compared with orthostatic normotension group, patients with OH or OHT showed lower levels of TIR (P < 0.001). The prevalences of OH and OHT both decreased with ascending TIR tertiles (OH, P < 0.001; OHT, P = 0.019), and both absolute SBP and DBP changes were negatively correlated with TIR (r = -0.171, -0.190, P < 0.05). After stratifying by BMI, only the prevalence of OH in the lower layer and the prevalence of OHT in the higher layer remained significant difference among tertiles of TIR. Multivariate logistics regression revealed that lower TIR and lower BMI were risk factors for OH, whereas lower TIR but higher BMI were risk factors for OHT.

CONCLUSIONS

We find a differential correlation dependent of BMI milieus between TIR and orthostatic BP status.

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).

Orthostatic Resiliency During Successive Hypoxic, Hypoxic Orthostatic Challenge: Successful vs. Unsuccessful Cardiovascular and Oxygenation Strategies

Introduction: Rapid environmental changes, such as successive hypoxic-hypoxic orthostatic challenges (SHHOC) occur in the aerospace environment, and the ability to remain orthostatically resilient (OR) relies upon orchestration of physiological counter-responses. Counter-responses adjusting for hypoxia may conflict with orthostatic responses, and a misorchestration can lead to orthostatic intolerance (OI). The goal of this study was to pinpoint specific cardiovascular and oxygenation factors associated with OR during a simulated SHHOC.

Methods: Thirty one men underwent a simulated SHHOC consisting of baseline (P0), normobaric hypoxia (Fi02 = 12%, P1), and max 60 s of hypoxic lower body negative pressure (LBNP, P2). Alongside anthropometric variables, non-invasive cardiovascular, central and peripheral tissue oxygenation parameters, were recorded. OI was defined as hemodynamic collapse during SHHOC. Comparison of anthropometric, cardiovascular, and oxygenation parameters between OR and OI was performed via Student’s t-test. Within groups, a repeated measures ANOVA test with Holm-Sidak post hoc test was performed. Performance diagnostics were performed to assess factors associated with OR/OI (sensitivity, specificity, positive predictive value PPV, and odd’s ratio OR).

Results: Only 9/31 were OR, and 22/31 were OI. OR had significantly greater body mass index (BMI), weight, peripheral Sp02, longer R-R Interval (RRI) and lower heart rate (HR) at P0. During P1 OR exhibited significantly higher cardiac index (CI), stroke volume index (SVI), and lower systemic vascular resistance index (SVRI) than OI. Both groups exhibited a significant decrease in cerebral oxygenation (TOIc) with an increase in cerebral deoxygenated hemoglobin (dHbc), while the OI group showed a significant decrease in cerebral oxygenated hemoglobin (02Hbc) and peripheral oxygenation (TOIp) with an increase in peripheral deoxygenated hemoglobin (dHbp). During P2, OR maintained significantly greater CI, systolic, mean, and diastolic pressure (SAP, MAP, DAP), with a shortened RRI compared to the OI group, while central and peripheral oxygenation were not different. Body weight and BMI both showed high sensitivity (0.95), low specificity (0.33), a PPV of 0.78, with an OR of 0.92, and 0.61. P0 RRI showed a sensitivity of 0.95, specificity of 0.22, PPV 0.75, and OR of 0.99. Delta SVI had the highest performance diagnostics during P1 (sensitivity 0.91, specificity 0.44, PPV 0.79, and OR 0.8). Delta SAP had the highest overall performance diagnostics for P2 (sensitivity 0.95, specificity 0.67, PPV 0.87, and OR 0.9).

Discussion: Maintaining OR during SHHOC is reliant upon greater BMI, body weight, longer RRI, and lower HR at baseline, while increasing CI and SVI, minimizing peripheral 02 utilization and decreasing SVRI during hypoxia. During hypoxic LBNP, the ability to remain OR is dependent upon maintaining SAP, via CI increases rather than SVRI. Cerebral oxygenation parameters, beyond 02Hbc during P1 did not differ between groups, suggesting that the during acute hypoxia, an increase in cerebral 02 consumption, coupled with increased peripheral 02 utilization does seem to play a role in OI risk during SHHOC. However, cardiovascular factors such as SVI are of more value in assessing OR/OI risk. The results can be used to implement effective aerospace crew physiological monitoring strategies.

Prospective analysis of syncope/pre-syncope in a tertiary paediatric orthopaedic fracture outpatient clinic

BACKGROUND

The incidence of vasovagal syncope (VVS) precipitated by medical procedures such as blood donation is quoted as between 0.13% and 4.17%. Vasovagal events have been observed to occur following cast removal at our paediatric orthopaedic clinic; however, there is no available information in the existing literature regarding incidence or risk factors. This study aims to identify the incidence and demographic traits of patients experiencing syncopal events following cast removal.

METHODS

Over a 12-month period, paediatric patients experiencing a syncopal or pre-syncopal event during an outpatient appointment for cast removal were prospectively enrolled into the study. Basic demographic data were recorded, as well as injury and procedure details and a description of the event. Statistical analysis as well as calculation of incidence of vasovagal events were performed.

RESULTS

A total of 6078 patients presented for cast removal in the 12-month period. Twenty syncopal or pre-syncopal events were recorded. Incidence was calculated as 0.32%. Mean patient age was 10.8 years. Male : female ratio was 2.3:1. Mean body mass index (BMI) was 20.08, with a trend for higher prevalence of males under the 50th BMI percentile-for-age. The mean time post-injury was 31.4 days. Ninety-five percent of patients were being treated for an upper limb injury and 30% had injuries that had been treated surgically. There were no associated secondary complications or injuries.

CONCLUSIONS

Incidence of VVS following cast removal is comparable to the values quoted in literature for other medical procedures. Demographic data of our cohort suggested that those who experienced VVS were predominantly young males of lower-than-average BMI.

Impact of body mass index on left atrial dimension in HOCM patients

Background

Substantial studies have demonstrated that left atrial (LA) enlargement was a robust predictor of atrial fibrillation (AF) and obesity was a modifiable risk factor for cardiovascular diseases. However, the role of body mass index (BMI) on LA dimension in hypertrophic obstructive cardiomyopathy (HOCM) remains unclear.

Methods

A total of 423 HOCM patients (average BMI 25.4 ± 3.4 kg/m²) were recruited for our study. Participants were stratified into three groups based on BMI: normal weight (BMI < 23 kg/m²), overweight (BMI 23–27.5 kg/m²), and obesity (BMI ≥ 27.5 kg/m²).

Results

Compared with normal weight, patients with obesity had significantly lower prevalence of syncope (p = 0.007) and moderate or severe mitral regurgitation (p = 0.014), and serum NT-proBNP (p = 0.004). Multiple linear regression analysis indicated that BMI (β = 0.328, p < 0.001), log NT-proBNP (β = 0.308, p < 0.001), presence of AF (β = 0.209, p = 0.001), and left ventricular diastolic diameter index (β = 0.142, p = 0.019) were independently related with LA diameter. However, BMI was not an independent predictor of the presence of AF on multivariable binary logistical regression analysis.

Conclusions

BMI was independently associated with LA diameter; however, it was not an independent predictor of prevalence of AF. These results suggest that BMI may promote incidence of AF through LA enlargement in HOCM.

Body mass index is a promising predictor of response to oral rehydration saline in children with vasovagal syncope

BACKGROUND

Vasovagal syncope (VVS) greatly impairs quality of life. The therapeutic efficacy of oral rehydration saline (ORS) for unselected VVS patients is not satisfactory due to the diverse mechanisms of the disease. Body mass index (BMI) was demonstrated to reflect blood volume to a certain extent. Therefore, the present study explored the capability of BMI to predict the therapeutic response of children with VVS to ORS treatment.

METHODS

Seventy-four children with VVS who visited the Syncope Unit of Pediatrics at Peking University First Hospital from November 2010 to June 2019 receiving ORS treatment were enrolled for this retrospective case-control study. A comparison of demographic, clinical, and hemodynamic characteristics was performed between responders and non-responders. The correlation between baseline BMI and response time was analyzed. To determine the value of baseline BMI in predicting the therapeutic efficacy of ORS in children with VVS, a receiver operating characteristic curve analysis was performed.

RESULTS

Fifty-two children were identified as responders, and the remaining 22 children were identified as non-responders. The baseline BMI of the responders was much lower than that of the non-responders (16.4 [15.5, 17.8] kg/m2vs. 20.7 ±e6 kg/m2, P < 0.001), and baseline BMI was positively correlated with response time in the head-up tilt test after adjusting for sex (r = 0.256, 95% confidence interval [CI]: 0.067-0.439, P = 0.029). The area under the receiver operating characteristic curve of baseline BMI was 0.818 (95% CI: 0.704-0.932, P < 0.001), and an optimal cut-off value of 18.9 kg/m2 yielded a sensitivity of 83% and a specificity of 73% to predict the efficacy of ORS in VVS.

CONCLUSION

Prior to treatment, baseline BMI is a promising predictor of response to ORS in children with VVS.

Orthostatic Hypotension and Novel Blood Pressure Associated Gene Variants in Older Adults: Data From the TILDA Study

Orthostatic hypotension (OH) is associated with increased risk of trauma and cardiovascular events. Recent studies have identified new genetic variants that influence orthostatic blood pressure (BP). The aim of this study was to investigate the associations of candidate gene loci with orthostatic BP responses in older adults. A total of 3,430 participants aged ≥50 years from The Irish Longitudinal Study on Ageing (TILDA) with BP measures and genetic data from 12 single-nucleotide polymorphism (SNP) linked to BP responses were analyzed. Orthostatic BP responses were recorded at each 10 s interval and were defined as OH (SBP drop ≥20 mmHg or DBP drop ≥10 mmHg) at the time-points 40, 90, and 110 s. We defined sustained OH (SOH) as a drop that exceeded consensus BP thresholds for OH at 40, 90, and 110 s after standing. Logistic regression analyses modeled associations between the candidate SNP alleles and OH. We report no significant associations between OH and measured SNPs after correction for multiple comparisons apart from the SNP rs5068 where proportion of the minor allele was significantly different between cases and controls for SOH 40 (p = .002). After adjustment for covariates in a logistic regression, those with the minor G allele (compared to the A allele) had a decreased incidence rate ratio (IRR) for SOH 40 (IRR 0.45, p = .001, 95% CI 0.29-0.72). Only one SNP linked with increased natriuretic peptide concentrations was associated with OH. These results suggest that genetic variants may have a weak impact on OH but needs verification in other population studies.

Risk factors and psychological impact of syncope in migraine patients

BACKGROUND

Migraine is associated with syncope. We investigated risk factors for syncope and burden of syncope in migraine patients.

METHODS

Participants were recruited from a headache clinic. All participants provided information on lifestyle, co-morbidity, syncope, headache and suicide, and completed the MIDAS and HADS questionnaires. Genetic data were available for a subset of participants. Risk of syncope in relation to participant's characteristics and migraine susceptibility loci, and risks of psychological disorders associated with syncope, were calculated using logistic regression.

RESULTS

Underweight, regular tea intake, diabetes mellitus, and migraine with aura were associated with increased syncope risks, with adjusted ORs of 1.76 (95% CI 1.03-3.03), 1.84 (95% CI 1.22-2.79), 4.70 (95% CI 1.58-13.95), and 1.78 (95% CI 1.03-3.10), respectively. Preliminary results showed that rs11172113 in LRP1 was associated with syncope risks. Comorbid syncope in migraine patients was associated with increased risks of depression (OR 1.95, 95% CI 1.18-3.22) and suicide attempt (OR 2.85, 95% CI 1.48-5.48).

CONCLUSION

Our study showed the potential roles of vascular risk factors in the association between migraine and syncope. Modifiable risk factors for syncope in patients with migraine include body mass index and tea intake. The debilitating psychological impact of co-morbid syncope in migraine patients warrants clinical attention of treating physicians.

Orthostatic intolerance in enhanced recovery laparoscopic colorectal resection

BACKGROUND

Orthostatic hypotension (OH) and intolerance (OI) are common findings in the early postoperative period after major surgery and may delay early mobilization. The mechanism of impaired orthostatic competence and OI symptoms is not fully understood, and specific data after colorectal surgery with well-defined perioperative care regimens and mobilization protocols are lacking. The aim of this study was to investigate the prevalence, possible risk factors and the impact of OI in patients undergoing elective minimal invasive colorectal cancer resection.

METHODS

A prospective single-centre study with an optimal enhanced recovery program and multimodal analgesic treatment. OI and OH were evaluated using a well-defined mobilization protocol preoperatively and 6 hour and 24 hour postoperatively.

RESULTS

A total of 100 patients were included in the data analysis. The overall median length of stay was 3 days (1-38). OI was observed in 53% of the patients 6 hour postoperatively and in 24% at 24 hour. OI at 6 hour postoperatively was associated with younger age, lower BMI, and female gender. At 24 hour postoperatively, female gender and ASA class >1 was associated with OI. Opioid consumption and intravenous fluid during the first 24 hour was not associated with OI. Postoperative complications were equally observed between patients with and without OI. Although not statistically significant, patients with OI at 24 hour postoperatively had prolonged LOS (mean 4.0 vs 7.5 days, P = 0.069) compared with patients without OI.

CONCLUSION

Postoperative orthostatic intolerance is a common problem during the first 24 hour following laparoscopic colorectal resection and may be followed by delayed recovery.

Pathophysiology of Noncardiac Syncope in Athletes

The most frequent cause of syncope in young athletes is noncardiac etiology. The mechanism of noncardiac syncope (NCS) in young athletes is neurally-mediated (reflex). NCS in athletes usually occurs either as orthostasis-induced, due to a gravity-mediated reduced venous return to the heart, or in the context of exercise. Exercise-related NCS typically occurs after the cessation of an exercise bout, while syncope occurring during exercise is highly indicative of the existence of a cardiac disorder. Postexercise NCS appears to result from hypotension due to impaired postexercise vasoconstriction, as well as from hypocapnia. The mechanisms of postexercise hypotension can be divided into obligatory (which are always present and include sympathoinhibition, histaminergic vasodilation, and downregulation of cardiovagal baroreflex) and situational (which include dehydration, hyperthermia and gravitational stress). Regarding postexercise hypocapnia, both hyperventilation during recovery from exercise and orthostasis-induced hypocapnia when recovery occurs in an upright posture can produce postexercise cerebral vasoconstriction. Athletes have been shown to exhibit differential orthostatic responses compared with nonathletes, involving augmented stroke volume and increased peripheral vasodilation in the former, with possibly lower propensity to orthostatic intolerance.