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For centuries, temperature measurement deficiencies attributable to biological barriers and low thermo-conductivity (k) have precluded accurate surface-based fever assessment. At this stage of the pandemic, infection detection in children (who due to immature immune system may not effectively respond to vaccines) is critical because children can be readily infected and also become a large mutation reservoir. We reveal hitherto-unrecognized worldwide body temperature measurements (T°), in children and adults, over tissue typified by low-k similar to wood that may reach 6.8°C in thermal variability, hampering thereby COVID-19 control. Brain-eyelid thermal tunnels’ (BTT) integration of low-k and high-k regions creating a thermal pathway for undisturbed heat transmission from hypothalamus to high-k skin eliminates current shortcomings and makes the brain indispensable for defeating COVID-19 given that brain thermoregulatory signals are not limited by mutations. Anatomo-histologic, emissive, physiologic, and thermometric bench-to-bedside studies characterized and overcome biophysical limitations of thermometry through high-k eyelid-enabled brain temperature measurements in children and adults. BTT eyelid features fat-free skin (~900 µm) and unique light emission through a blood/fat configuration in the underlying tunnel. Contrarily, forehead features variable and thick dermis (2000–2500 µm) and variable fat layers (1100–2800 µm) resulting in variable low-k as well as temperatures 1.97 °C lower than BTT temperature (BTT°). Highest emission present in only ~3.1% of forehead averaged 1.08±0.49 °C (mean±SD) less than BTT° (p=0.008). Environmental and biological impacts during fanning revealed thermal imaging limitations for COVID-19 screening. Comparison of paired measurements for 100 pediatric patients showed that in the children subgroup above 37°C, BTT° exceeded body core temperature (Core°) in 60/72 patients; the average difference in the 72 patients was 0.62±0.7°C (p

Essential to management of pandemics, noninvasive thermometry has been hampered by inaccuracies and inconsistencies, due to measurements on low thermal conductivity (k) surfaces we show here, which have precluded effective assessment of febrile states for centuries. Discovery of brain-eyelid thermal tunnels (BTT) identified undisturbed thermal transmission from brain. We here report a series of integrated anatomic, histologic, thermal emissive, thermal physiologic and thermometric studies designed to identify, characterize and overcome the biophysical limitations of surface thermometry as currently used worldwide to control COVID-19, which primarily relies on non-contact forehead thermometry. However, the forehead has thick and variable dermis (~2000 µm to ~2500 µm) and fat layers (~1100 µm to ~2800 µm) resulting in low-k insulation equivalent to wood. During thermal emission, the highest skin temperature at forehead, present in only ~3.1% of forehead, averaged 1.07±0.49°C (mean±SD) less than over BTT (p=0.008, two-tailed paired t-test). Thermometric studies (without correction factor) revealed 1.97°C higher temperature at BTT site (BTT°) than forehead. Facial fanning caused 3.5°C reduction in forehead temperature, which do not compromise BTT site, attributable to impact on non-BTT surface sites by highly variable surface vasculature. Cerebral hemisphere dominance studies uncovered higher BTT° in the dominant side (P

We herein performed a series of brain/core temperature discordance studies in setting of brain excitation and depression to assess whether noninvasive temperature measurement at highly transmissive eyelid skin overlying newly discovered brain-eyelid thermal tunnel (BTT°) is specific for brain as opposed to core temperature (Core°). BTT°-Core° was determined during hypothermic cardiopulmonary bypass (CPB), seizures induced during electroconvulsive therapy (ECT), pharmacologic depression by sedation and anesthesia, sleep, stroke, brain trauma, and exercise in hot environmental chamber. During brain-core decoupling BTT° follows brain neuronal activity. BTT°-Core° varied dramatically due to extreme changes during CPB. During ECT, BTT° ipsilateral to induced seizure increased from 36.38±0.4°C pre-seizure to 36.69°±0.3°C at two minute post-seizure (p

Fat is recognized as low thermoconductivity (k) tissue and barrier for thermal transmission. We here identify and characterize morphologically, radiologically, and thermo-physically fat-enabled bilateral integrated blood/fat/skin thermal pathways, referred as Brain-eyelid Thermal Tunnels (BTT), that enable undisturbed thermal transmission between brain and uniquely radiant high-k skin in the right and left eyelids. We elucidated cranial "aberrancies", justified the facial "death triangle" and uncovered perihypothalamic thermoregulatory-sensory triunal inherent to brain thermal homeostasis that revealed thermal communication among brain, heart, and environment. Our results introduce the first evidence for a brain↔surface thermo-physical pathway and biological thermal waveguide. Said transmission was documented by an isolated beam of emission at the ipsilateral BTT terminus. We showed brain thermal transfer via BTT during neurosurgery by comparison of noninvasive temperature measurement at the BTT site (BTT°) to direct temperature measurement in brain parenchyma (Parenchyma°) in open craniotomy (BTT° - Parenchyma° = 0.012±0.2°C, p=0.91), as opposed to 0.45°C difference between BTT° and core temperature. This indicates that BTT° provides an accurate noninvasive method for measuring human brain temperature unimpeded by the body's thermal barrier through transorbital thermo-physical configurations.

The aim of this study was to analyze risk factors and outcomes of vasoplegia after cardiac surgery based on our experience with almost 2000 cardiac operations performed at our institution.We retrospectively analyzed patients who underwent cardiac surgery with cardiopulmonary bypass (CPB) between 2011 and 2013. Data were available for a total of 1992 patients. We defined vasoplegia as hypotension with persistently low systemic vascular resistance (800 dyn/s/cm) and preserved Cardiac Index (2.5).The rate of vasoplegia in our cohort was 20.3% (n = 405). The incidences of mild, moderate, and severe vasoplegia were 13.2, 5.7, and 1.5%, respectively. Factors that increased risk of vasoplegia included valve operations, heart transplants, dialysis-dependent renal failure, age65, diuretic therapy, and recent myocardial infarction. B blocker therapy was protective against vasoplegia.Vasoplegic syndrome is still a frequently occurring adverse event following cardiac surgery. In high risk patients for vasoplegia, it may be sensible to proceed with preoperative volume loading (instead of diuresis), initiation of low dose vasopressin therapy if needed, and attempting to up titrate beta-blocker therapy.

Background Whether there is a cardiac surgical patient population that does not incur harm from blood conservation is unknown. This study aimed to identify patient characteristics associated with patients who safely tolerate blood conservation. Methods We conducted a retrospective review of consecutive patients undergoing isolated coronary artery bypass graft surgery or isolated aortic valve replacement, or concomitant coronary artery bypass graft surgery and aortic valve replacement between 2011 and 2016, during which blood conservation intervention took place. Logistic regression derived from the preintervention cohort was applied to the postintervention cohort to identify patient characteristics associated with those predicted to be transfused in the preintervention era but were not in the postintervention era. Results In this series of 2,701 adult patients undergoing cardiac operations, blood conservation intervention in 2014 led to a 52% reduction in red blood cell transfusion. Between preintervention and postintervention cohorts, there was no significant difference in the measured outcomes. A regression model derived from the preintervention cohort was applied to the postintervention cohort to identify predictors of cohort that do not derive benefit from liberal transfusion. This model demonstrated such patient characteristics to be age more than 75 years (odds ratio [OR] 1.71, 95% confidence interval [CI]: 1.09 to 2.68, p = 0.033), body mass index less than 30 kg/m2 (OR 1.5, 95% CI: 1.02 to 2.20, p = 0.044), lowest intraoperative hematocrit between 22 and 25 (OR 1.77, 95% CI: 1.16 to 2.68, p Conclusions Blood conservation can successfully yield reduction in perioperative blood product use, with associated decrease in the risk of postoperative renal failure. A select patient population who may tolerate blood conservation safely was identified, and that may guide a targeted blood conservation effort.

The pathophysiology of myocardial injury that results from cardiac ischemia and reperfusion (I/R) is incompletely understood. Experimental evidence from murine models indicates that innate immune mechanisms including complement activation via the classical and lectin pathways are crucial. Whether factor B (fB), a component of the alternative complement pathway required for amplification of complement cascade activation, participates in the pathophysiology of myocardial I/R injury has not been addressed. We induced regional myocardial I/R injury by transient coronary ligation in WT C57BL/6 mice, a manipulation that resulted in marked myocardial necrosis associated with activation of fB protein and myocardial deposition of C3 activation products. In contrast, in fB-/- mice, the same procedure resulted in significantly reduced myocardial necrosis (% ventricular tissue necrotic; fB-/- mice, 20 ± 4%; WT mice, 45 ± 3%; P < 0.05) and diminished deposition of C3 activation products in the myocardial tissue (fB-/- mice, 0 ± 0%; WT mice, 31 ± 6%; P

t d p t l ACCORDING TO THE American Heart Association 2010 update, more than 5.7 million people in the United States uffer from heart failure.1-3 The prevalence of heart failure in the United States has been rising with the aging population. The annual number of heart failure–related hospitalizations has risen to more than 1 million and has resulted in combined direct and indirect costs approximating $40 billion.1,2 Despite adancements in the pharmacologic management of heart failure, ortality rates have remained relatively unchanged. After a iagnosis of heart failure, the 1-year mortality rate is 20%,1 and nce a patient has American College of Cardiology/American eart Association stage D heart failure (ie, end-stage heart ailure), the 2-year mortality rate approaches 75%.4 Although ardiac transplantation has excellent results for the treatment of nd-stage heart failure, this option is limited severely by the umber of available donor organs, with the annual number of eart transplants having plateaued at approximately 2,300 over he last 15 years. In 1991, since the landmark Randomized valuation of Mechanical Assistance of Chronic Heart Failure REMATCH) trial showed improved 1and 2-year survival ates in the mechanical circulatory support group versus the edical management group,5 left ventricular assist devices (LVADs) have taken a more prominent role in the management of heart failure. Since 2006 when the Interagency Registry for Mechanically Assisted Circulatory Support started collecting data on mechanical circulatory support devices, more than 3,000 primary adult LVADs have been implanted.6 Parides et al7 estimated that between 20,000 and 60,000 patients could enefit from LVAD therapy annually.

The impact of 17β-oestradiol (E2) exposure on autonomic control of orthostasis in young women is unclear. We tested the hypothesis that autonomic cardiovascular regulation is more sensitive to E2 exposure in women with low orthostatic tolerance. Women underwent an initial maximal lower body negative pressure (LBNP) test to place them into a low (LT, n = 7, 22 ± 1 years old, body mass index 22 ± 1 kg m(-2)) or a high orthostatic tolerance group (HT, n = 7, 22 ± 1 years old, body mass index 24 ± 1 kg m(-2)). We then suppressed endogenous reproductive hormone production using a gonadotrophin-releasing hormone antagonist (GnRHant) for 10 days, with E2 administration during the last 7 days of GnRHant. We measured R-R interval and beat-by-beat blood pressure during the modified Oxford protocol, and changes in heart rate, blood pressure and forearm vascular resistance (FVR) during submaximal LBNP. During submaximal LBNP, FVR increased in HT (ANOVA P 0.05), and stroke volume was lower in LT relative to HT at all levels of LBNP (P < 0.05). Compared with GnRHant, E2 administration shifted FVR lower in LT (ANOVA P < 0.05), with no effect in HT. Administration of E2 increased baroreflex control of heart rate (derived from the modified Oxford protocol) in LT (GnRHant 10.7 ± 2.5 ms mmHg(-1) vs. E2 16.1 ± 2.4 ms mmHg(-1), P < 0.05) but not in HT (GnRHant 13.4 ± 1.9 ms mmHg(-1) vs. E2 15.3 ± 2.4 ms mmHg(-1), n.s.). In conclusion, blunted peripheral vasoconstriction and lower stroke volume contribute to compromised orthostatic tolerance in women; this inability to vasoconstrict is further exacerbated by exposure to E2. Furthermore, E2 administration increases baroreflex-mediated heart rate responses to orthostasis in low orthostatic tolerant women, which is likely to be a compensatory mechanism for the blunted peripheral vascular resistance and lower central volume.

Ventricular fibrillation is common after aortic cross-clamp release in patients undergoing open-heart surgeries. The aim of the study was to evaluate the efficacy of the prophylactic administration of 150 mg amiodarone by way of the pump 2 min before release of aortic cross-clamp in preventing ventricular fibrillation.The present study is a prospective, randomized, controlled and blinded study performed at a teaching university hospital where 120 patients undergoing coronary bypass graft surgery were randomly assigned to three groups. Each group received either 150 mg of amiodarone or 100 mg lidocaine or isotonic saline by way of pump 2 min before release of the aortic cross-clamp. The frequency of occurrence of ventricular fibrillation and the subsequent required defibrillation counter shocks were determined in all groups.The frequency of occurrence of ventricular fibrillation was significantly higher in both the amiodarone (48%) and the control group (45%) as compared with the lidocaine group (20%) with no statistically significant difference between the amiodarone and the control groups. Furthermore, when ventricular fibrillation occurred, the percentage of patients requiring defibrillation counter shocks was significantly higher in both the amiodarone (58%) and control (61%) groups as compared with the lidocaine group (13%) with no difference between the amiodarone and the control groups, despite a significant decrease in the defibrillation counter shocks energy requirements in the amiodarone group.The present study showed no difference between amiodarone (150 mg) and placebo in preventing ventricular fibrillation after release of aortic cross-clamp. In addition, the use of lidocaine was able to reduce the incidence of ventricular fibrillation as compared with both amiodarone and placebo.

Patients who have valvular heart disease coming for surgery presentmany challenges to the anesthesiologist. Over the past three decades therehas been a persistent improvement in our understanding of the pathophys-iology of valvular heart disease and in the surgical techniques for correctingit. With the development of efficient and safe noninvasive monitoring of car-diac function, new surgical techniques, better designs of prosthetic valves,and with the development of useful guidelines for choosing the proper tim-ing of surgical intervention, patients who have valvular disease with varyingphysiology can be encountered in the perioperative period. The periopera-tive physician has to be aware of the varying effects of hemodynamic vari-ables on this subpopulation of patients. In general, the goal in stenoticlesions is to enhance forward flow, whereas in regurgitant lesions the goalis to decrease regurgitant flow. The timing for surgery has also undergonesignificant changes. Now it is no longer necessary or even advisable to delaysurgery until advanced symptoms are present; thus surgery is timed earliertoday than it was even a decade ago. On the other hand, many, but notall patients who have advanced disease, once considered inoperable, arenow often helped substantially by valve surgery [1]. According to the Amer-ican College of Cardiology/American Heart Association (ACC/AHA)guidelines, severe valvular disease is considered a major clinical predictorof cardiac risk, and should lead to consideration of delay or cancellationof elective noncardiac surgery and consideration of echocardiography,cardiac catheterization, or possible valve surgery [2]. The five variables indealing with valvular heart diseases are: (1) preload, (2) afterload, (3)myocardial contractility, (4) heart rate, and (5) rhythm. The goals of anes-thesia for each valvular disease are described below in terms of these fivevariables. The monitoring for patients who have any of the valvular

Use of ultrasound in the acute care setting has become more common in recent years. However, it still remains underutilized in the perioperative management of critical patients. In this review, we aim to increase the awareness of ultrasound as an important diagnostic modality that can be used in the perioperative period to improve patient care. Our main focus will be in describing the diagnostic uses of ultrasound to identify cardiac, pulmonary, airway and vascular diseases commonly encountered in acute care settings.We find that ultrasound can be used in a quick fashion to assess a haemodynamically unstable patient. Protocols are available to use ultrasound as a part of cardiopulmonary resuscitation. Ultrasound can help in deciding fluid vs. pressor treatment by evaluating the inferior vena cava and other cardiac structures.Lung ultrasound can not only help in diagnosing pneumothoracies and effusions but also look at lung recruitment and diaphragmatic movement, hence can aid in deciding extubation strategies. This modality can be utilized for confirmation of endotracheal tube.Recent interest in axillary vein cannulation with ultrasound guidance has gained some momentum.This article covers the recent developments and literature available on point of care ultrasound and its utilization in the perioperative period. We have not covered some other important uses of ultrasound such as abdominal examination looking at the aorta and other abdominal organs. This was beyond the scope of this article.

Rapid detection of hemostatic defects presents a challenge for the anesthesiologist who must balance anesthetic and surgical considerations for maintaining adequate platelet and coagulant factors, while keeping allogenic blood exposure to a minimum. The Clot Signature Analyzer®, a point-of-care device capable of rapid response and easy interpretation is described here. Its applicability in two obstetrical patients with platelet dysfunction is discusssed.

This article reviews the current state of knowledge of the pathophysiology, diagnosis, and treatment of acute coronary syndrome outside and during the perioperative period. It highlights some aspects of relevance for the anesthesiologist caring for these patients. Perioperative modalities for the management of patients suffering from this syndrome, the major guidelines and the evidence behind them, and possible avenues for future research is explored.

The objective of this study was to determine the relationship between systemic vascular resistance (SVR), fingerear photoplethysmographic measurements in 14 adult patients undergoing coronary artery bypass grafting (CABG).Patients were monitored with photoplethysmographs of the finger and ear and continuous cardiac output (QT) via thermodilution catheter. The relationship between SVR, finger plethysmographic amplitude, width and ear plethysmographic amplitude, width was assessed with linear regression.The finger plethysmographic amplitude had a low correlation r value = -0.15, while finger plethysmographic width had a better correlation r value = 0.56. The correlation between SVR and ear plethysmographic amplitude and width were -0.24 and 0.62 respectively. Using receiver operating characteristic analysis the ear plethysmographic width had both better sensitivity and specificity than the finger plethysmographic width in identifying high and low SVR. Using a multiple regression analysis, SVR was estimated from the pulse oximeter waveforms: SVR calculated = 27.27 + (3978.53 x Ear pulse oximeter width) - (8.91 x Ear pulse oximeter area) + (1986.3 x Finger pulse oximeter width). Bland-Altman analysis was used the bias was 29.8 dynes s cm(-5), standard deviation was 587.3, upper and lower limit of agreement were 1204.45, and -1144.8 dynes s cm(-5) respectively.The data indicate that pulse width of finger and ear plethysmographic tracing are more sensitive to changes in SVR than the other indices. An appreciation of changes in pulse width may provide valuable evidence with respect to changes in peripheral vascular tone.