Cardiac neuromodulation with acute intermittent hypoxia in rats with spinal cord injury

It is well recognized that the interruption in bulbospinal sympathetic projections is the main cause of cardiovascular instability in individuals and experimental animals with spinal cord injury (SCI). Whether interrupted bulbospinal sympathetic projections contribute to cardiac dysfunction directly (i.e. input to the heart) or indirectly (i.e. vascular influences that alter loading conditions on the heart) post-SCI remains unknown, as does the potential effect of SCI-induced alterations in parasympathetic control on heart function. We employed a sequential pharmacological blockade approach to bridge this knowledge gap and additionally examined whether acute intermittent hypoxia (AIH) is capable of neuromodulating the heart post-SCI. In two experiments, rats were given T3 contusion SCI and survived for 2 weeks. At 2 weeks post-SCI, rats were instrumented with left ventricular and arterial catheters to assess cardiovascular function in response to either a sequential pharmacological blockade targeting different sites of the autonomic neuraxis (experiment 1) or AIH (experiment 2). The findings from experiment 1 revealed that impaired direct sympathetic transmission to the heart underlies the majority of the SCI-induced reduction in heart function post-SCI. The findings from experiment 2 revealed that a single-session of AIH increased left ventricular pressure generation and arterial blood pressure immediately and up to 90 min post-AIH. Together, our findings demonstrate that disrupted bulbospinal sympathetic pathways contribute directly to the SCI-induced impairment in left ventricular function. We also show that a single session of AIH is capable of neuromodulating the heart post-SCI. KEY POINTS: The loss of sympathetic transmission to the heart is the main cause of reduced cardiac function in a rodent model of spinal cord injury (SCI). Parasympathetic control remains unaltered post-SCI and does not contribute to reduced cardiac function post-SCI. Acute intermittent hypoxia neuromodulates the heart and increases left ventricular pressure generating capacity.

Difficult airway management in a patient with severe mitral and tricuspid regurgitation, rapid atrial fibrillation, and moderate pulmonary hypertension: a case report

BACKGROUND

Given the prevalence of cardiovascular disease, encountering difficult airways in this patient population is quite common. The challenge for anesthesiologists lies not only in establishing the airway but also in managing the hemodynamic instability caused by sympathetic activation during intubation. The purpose of this report is to describe the anesthetic experience of this patient with severe mitral and tricuspid regurgitation, atrial fibrillation with rapid ventricular response, and moderate pulmonary hypertension with an anticipated difficult airway.

CASE PRESENTATION

This case report describes intubation with fibreoptic bronchoscopy after the induction of general anesthesia in a cardiac surgical patient diagnosed with severe mitral and tricuspid regurgitation, rapid atrial fibrillation, and moderate pulmonary hypertension who underwent mitral and tricuspid valve replacements. The patient had a history of difficult intubation. Therefore, having considered that the benefits of intubation after general anesthesia induction outweighed the risks of awake intubation, the choice of fibreoptic bronchoscopy-guided intubation was performed following general anesthesia induction. No adverse events occurred throughout the proceeding.

CONCLUSION

This case highlights the importance of considering both airway safety and maintaining hemodynamic stability when cardiac surgery patients encounter an anticipated difficult airway. Awake intubation is not the only option, and intubation after general anesthesia may be considered when the benefits are evaluated to outweigh the risks.

Vascular limitations in blood pressure regulation with age in women: Insights from exercise and acute cardioselective β-blockade

Younger women rely on altering cardiac output (Q ̇ $\dot{Q}$ ) to regulate blood pressure (BP). In contrast, older women rely more on altering vascular tone. However, evidence suggests that the ability to alter systemic vascular conductance (SVC) is diminished in older women. In the present study, cardioselective β-blockade was utilized to diminish the relative contribution ofQ ̇ $\dot{Q}$ to BP regulation and thereby evaluate age-related vascular limitations in women at rest and during large muscle dynamic exercise. Younger (n = 13, mean age 26.0 years) and older (n = 14, mean age 61.8 years) healthy women performed submaximal bouts of semi-recumbent cycling exercise at varying intensities while receiving an intravenous infusion of esmolol, a β1-antagonist, or saline control in a repeated-measures crossover design.Q ̇ $\dot{Q}$ was attenuated during esmolol infusion, with greater reductions during exercise (moderate, -1.0 (95% CI, -1.6 to -0.5) L/min, P < 0.001; heavy, -2.0 (95% CI, -2.6 to -1.5) L/min, P < 0.001) than seated rest (-0.5 (95% CI, -1.1 to 0.0) L/min, P = 0.048), and this reduction was not significantly different between age groups (P = 0.122). Older women exhibited a greater attenuation in mean arterial pressure (MAP) during esmolol (-7 (95% CI, -9 to -4) mmHg, P < 0.001) relative to younger women (-2 (95% CI, -5 to 0) mmHg, P = 0.071). These changes coincided with a greater reduction of SVC in the younger women during esmolol (-15 (95% CI, -20 to -10) mL/min/mmHg, P < 0.001) compared to older women (-3 (95% CI, -9 to 2) mL/min/mmHg, P = 0.242). Together, these findings provide evidence that older, postmenopausal women have a diminished ability to adjust SVC in order to regulate MAP.

The left ventricle increases contractility in response to baroreceptor unloading, which is sympathetically mediated in the anesthetized rat

Contemporary discussion of the baroreflex includes the efferent vascular-sympathetic and cardiovagal arms. Since sympathetic postganglionic neurons also innervate the left ventricle (LV), it is often assumed that the LV produces a sympathetically mediated increase in contractility during baroreceptor unloading, but this has not been characterized using a load-independent index of contractility. We aimed to determine 1) whether LV contractility increases in response to baroreceptor unloading and 2) whether such increases are mediated via the sympathetic or parasympathetic arm of the autonomic nervous system. Ten male Wistar rats were anesthetized (urethane) and instrumented with arterial and LV pressure-volume catheters to measure mean arterial pressure (MAP) and load-independent LV contractility [maximal rate of increase in pressure adjusted to end-diastolic volume (PAdP/dtmax)], respectively. Rats were placed in a servo-controlled lower-body negative pressure (LBNP) chamber to reduce MAP by 10% for 60 s to mechanically unload baroreceptors under control conditions. LBNP was repeated in each animal following infusions of cardiac autonomic blockers using esmolol (sympathetic), atropine (parasympathetic), and esmolol + atropine. Under control conditions, PAdP/dtmax increased during baroreceptor unloading (26 ± 6 vs. 31 ± 9 mmHg·s-1·μL-1, P = 0.031). During esmolol, there was no increase in LV contractility during baroreceptor unloading (11 ± 2 vs. 12 ± 2, P = 0.125); however, during atropine, there was an increase in LV contractility during baroreceptor unloading (26 ± 6 vs. 31 ± 9, P = 0.019). During combined esmolol and atropine, there was a small increase in contractility versus control (13 ± 3 vs. 15 ± 4, P = 0.046). Our results demonstrate that, in anesthetized rats, LV contractility increases in response to baroreceptor unloading, which is largely sympathetically mediated.NEW & NOTEWORTHY This study empirically demonstrates a sympathetically mediated increase in LV contractility in response to baroreceptor unloading using a load-independent index of cardiac contractility in the anesthetized rat.

Antiarrhythmic Drug Dosing in Children-Review of the Literature

Antiarrhythmic drugs represent a mainstay of pediatric arrhythmia treatment. However, official guidelines and consensus documents on this topic remain scarce. There are rather uniform recommendations for some medications (including adenosine, amiodarone, and esmolol), while there are only very broad dosage recommendations for others (such as sotalol or digoxin). To prevent potential uncertainties and even mistakes with regard to dosing, we summarized the published dosage recommendations for antiarrhythmic drugs in children. Because of the wide variations in availability, regulatory approval, and experience, we encourage centers to develop their own specific protocols for pediatric antiarrhythmic drug therapy.

Opioid-Free Anesthesia for Craniotomy

BACKGROUND

Perioperative opioids are problematic following craniotomy as they can impede neurological examination because of excessive sedation and mask surgical complications. Multimodal anesthetic techniques including nerve blocks have been used successfully to deliver opioid-free anesthesia in other surgical populations; however, no clinical data evaluating opioid-free anesthesia for craniotomy exists within the current body of literature.

MATERIALS AND METHODS

Six prospectively identified patients underwent supratentorial craniotomy at Emory University Hospital using a multimodal opioid-free anesthetic (OFA) technique consisting of preoperative scalp block, dexmedetomidine and intravenous acetaminophen. These opioid-free patients were matched by age, sex, incision length, and incision location to 18 retrospectively identified control patients who underwent craniotomy using conventional, opioid-based anesthetic techniques. Postoperative opioid consumption and pain scores were compared and analyzed for noninferiority.

RESULTS

Noninferiority of the OFA technique was demonstrated for opioid consumption at all measured intervals from postanesthesia care unit arrival to 24 hours postoperatively. Noninferiority was also demonstrated with respect to average postoperative pain scores from 0 to 12 hours, 0 to 24 hours, as well as length of postanesthesia care unit stay. Noninferiority was not shown for time to first rescue opioid postoperatively, pain scores for the 12 to 24 hours postoperative period, or time to emergence from anesthesia.

CONCLUSIONS

This pilot study demonstrates the feasibility of an OFA technique for patients undergoing supratentorial craniotomy and suggests that larger prospective randomized controlled trials are indicated to examine the role of multimodal anesthetic techniques for craniotomy.

Maintenance over Time of the Effect Produced by Esmolol on the Structure and Function of Coronary Arteries in Hypertensive Heart Diseases

We previously observed that esmolol treatment for 48 h reduced vascular lesions in spontaneously hypertensive rats (SHRs). Therefore, we investigated whether this beneficial effect is persistent after withdrawal. Fourteen-month-old SHRs (SHR-Es) were treated with esmolol (300 μg/kg/min) or a vehicle for 48 h. Two separate groups were also given identical treatment, but they were then monitored for a further 1 week and 1 month after drug withdrawal. We analyzed the geometry and composition of the coronary artery, vascular reactivity and plasma redox status. Esmolol significantly decreased wall thickness (medial layer thickness and cell count), external diameter and cross-sectional area of the artery, and this effect persisted 1 month after drug withdrawal. Esmolol significantly improved endothelium-dependent relaxation by ACh (10⁻⁹–10⁻⁴ mol/L); this effect persisted 1 week (10⁻⁹–10⁻⁴ mol/L) and 1 month (10⁻⁶–10⁻⁴ mol/L) after withdrawal. Esmolol reduced the contraction induced by 5-HT (3 × 10⁻⁸–3 × 10⁻⁵ mol/L), and this effect persisted 1 week after withdrawal (10⁻⁶–3 × 10⁻⁵ mol/L). Esmolol increased nitrates and reduced glutathione, and it decreased malondialdehyde and carbonyls; this enhancement was maintained 1 month after withdrawal. This study shows that the effect of esmolol on coronary remodeling is persistent after treatment withdrawal in SHRs, and the improvement in plasma oxidative status can be implicated in this effect.

Effect of Different Concentrations of Esmolol on Perioperative Hemodynamics and Analgesia in Patients Undergoing Colectomy: A Prospective, Randomized Controlled Study

Purpose

The aim of this study was to investigate the efficacy of esmolol on intraoperative hemodynamic and perioperative analgesic management.

Methods

Totally, 125 patients undergoing colectomy were randomly divided into three groups. Group S (saline group) was administered 0.75 mL/kg/h of normal saline for 5 min before anesthesia induction and maintenance of 0.25 mL/kg/h; Group E₁ and Group E₂ were administered 0.5 mg/kg and 1.0 mg/kg esmolol for 5 min before anesthesia induction, and maintained of 0.5 mg/kg/h and 2.0 mg/kg/h, respectively. Several parameters including indexes of hemodynamics variation (primary outcome), intra- and postoperative analgesic usage, and pain score were measured.

Results

Group E₁ and Group E₂ had significantly lower intubation response than Group S (P = 0.007, P = 0.001), and extubation response of Group E₂ was significantly lower than Group S (P = 0.007). The opioid consumption in Group E₁ and Group E₂ was significantly lower than in Group S intraoperatively (P = 0.020 and 0.007). The incidence of postoperative adverse reactions among the three groups was not statistically significant (P = 0.368 and 0.772).

Conclusion

Esmolol 0.5 mg/kg and 1.0 mg/kg infusion before intubation both can effectively inhibit the intubation response, while only maintenance with 2.0 mg/kg/h of esmolol can reduce the incidence of extubation response. At the same time, esmolol can decrease intraoperative opioid requirement without increasing the risk of adverse reactions.

Trial Registration

ChiCTR1900024538 and the date of registration was July 15, 2019 at http://www.chictr.org.cn.

Using Esterase Selectivity to Determine the In Vivo Duration of Systemic Availability and Abolish Systemic Side Effects of Topical β-Blockers

For disorders of the skin, eyes, ears, and respiratory tract, topical drugs, delivered directly to the target organ, are a therapeutic option. Compared with systemic oral therapy, the benefits of topical treatments include a faster onset of action, circumventing the liver first pass drug metabolism, and reducing systemic side effects. Nevertheless, some systemic absorption still occurs for many topical agents resulting in systemic side effects. One way to prevent these would be to develop drugs that are instantly degraded upon entry into the bloodstream by serum esterases. Because topical β-blockers are used in glaucoma and infantile hemeangioma and cause systemic side effects, the β-adrenoceptor system was used to test this hypothesis. Purified liver esterase reduced the apparent affinity of esmolol, an ester-containing β-blocker used in clinical emergencies, for the human β-adrenoceptors in a concentration and time-dependent manner. However, purified serum esterase had no effect on esmolol. Novel ester-containing β-blockers were synthesized and several were sensitive to both liver and serum esterases. Despite good in vitro affinity, one such compound, methyl 2-(3-chloro-4-(3-((2-(3-(3-chlorophenyl)ureido)ethyl)amino)-2-hydroxypropoxy)phenyl)acetate, had no effect on heart rate when injected intravenously into rats, even at 10 times the equipotent dose of esmolol and betaxolol that caused short and sustained reductions in heart rate, respectively. Thus, ester-based drugs, sensitive to serum esterases, offer a mechanism for developing topical agents that are truly devoid of systemic side effects. Furthermore, differential susceptibility to liver and serum esterases degradation may also allow the duration of systemic availability for other drugs to be fine-tuned.

Esmolol in the management of pre-hospital refractory ventricular fibrillation: A systematic review and meta-analysis

BACKGROUND

Esmolol has been proposed as a viable adjunctive therapy for pre-hospital refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT).

OBJECTIVES

We performed a systematic review and meta-analysis to assess the effectiveness of esmolol on pre-hospital refractory VF/pVT, compared with standard of care.

METHODS

MEDLINE, Embase, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched for eligible studies. Two investigators independently extracted relevant data and assessed the methodological quality of each included study using the ROBINS-I tool. The quality of evidence for summary estimates was assessed according to GRADE guidelines. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) for each outcome of interest were calculated.

RESULTS

The search yielded 3253 unique records, of which two studies were found to be in accordance with the research purpose, totaling 66 patients, of whom 33.3% (n = 22) received esmolol. Additional evidence was provided in the paper but was not relevant to the analysis and was therefore not included. Esmolol was likely associated with an increased rate of survival to discharge (RR 2.82, 95% CI 1.01-7.93, p = 0.05) (GRADE: Very low) and survival with favorable neurological outcome (RR 3.44, 95% CI 1.11-10.67, p = 0.03) (GRADE: Very low). Similar results were found for return of spontaneous circulation (ROSC) (RR 2.63, 95% CI 1.37-5.07, p = 0.004) (GRADE: Very low) and survival to intensive care unit (ICU)/hospital admission (RR 2.63, 95% CI 1.37-5.07, p = 0.004) (GRADE: Very low).

CONCLUSION

The effectiveness of esmolol for refractory VF/pVT remains unclear. Trial sequential analysis (TSA) indicates that the evidence is inconclusive and that further trials are required in order to reach a conclusion. Therefore, it is imperative to continue to accumulate evidence in order to obtain a higher level of scientific evidence.

Atrial Fibrillation in COVID-19: From Epidemiological Association to Pharmacological Implications

Coronavirus disease 2019 (COVID-19) outbreak is a public health emergency of international concerns because of a highly pathogenic human coronavirus (HCoV), actually named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite much emerging data about the epidemiological association between cardiovascular diseases and COVID-19, little is still known about atrial fibrillation and its optimal management in this clinical contest. The aim of our review is to describe the pharmacological interactions between cardiovascular drugs more commonly used in atrial fibrillation management and experimental COVID-19 therapies, based on EU and US summaries of product characteristics.

Esmolol inhibits inflammation and apoptosis in the intestinal tissue via the overexpression of NF-κB-p65 in the early stage sepsis rats

BACKGROUND/AIMS

Accumulating evidence reveals esmolol could protect the gut mucosa through the regulation of immune response and inflammation in patients with sepsis. However, its underlying mechanism is not fully understood.

MATERIALS AND METHODS

Diamine oxidase (DAO), intestinal fatty acid-binding protein (I-FABP), interleukin (IL)-6, and IL-10 in the plasma of rats were detected by ELISA assay. Western blotting was utilized to measure the expression levels of NF-kappa B-p65, Bcl-2, and cleaved caspase-3 in the intestinal tissues. The survival analysis was performed in each group.

RESULTS

The plasma levels of DAO and IL-10 levels were increased, whereas that of I-FABP and IL-6 were decreased in the sepsis rats after esmolol treatment, indicating that after the esmolol treatment, the intestinal inflammation and damages were remarkably reduced as compared to those in the normal saline treated sepsis rats. NF-κB-p65 and Bcl-2 were highly expressed, but cleaved caspase-3 showed lower expression in the esmolol treated groups. However, at the same time, we observed contrasting results in the normal saline treated group. Western blotting data indicated that the esmolol treatment inhibited the inflammation and apoptosis in the intestinal tissue due to the overexpression of NF-κB-p65 in the celiac sepsis rats. The survival analysis results indicate that the esmolol infusion should be used in the early stages sepsis rats.

CONCLUSION

Esmolol can suppress inflammation and apoptosis in the intestinal tissue via the overexpression of NF-kappa B-p65 in the early stage sepsis rats. kappa BEarly-stage use of esmolol might be an ideal treatment method for sepsis.

Left Ventricular Twist Is Augmented in Hypoxia by β1-Adrenergic-Dependent and β1-Adrenergic-Independent Factors, Without Evidence of Endocardial Dysfunction

BACKGROUND

Left ventricular (LV) twist mechanics are augmented with both acute and chronic hypoxemia. Although the underlying mechanisms remain unknown, sympathetic activation and a direct effect of hypoxemia on the myocardium have been proposed, the latter of which may produce subendocardial dysfunction that is masked by larger subepicardial torque. This study therefore sought to (1) determine the individual and combined influences of β₁-AR (β₁-adrenergic receptor) stimulation and peripheral O₂ saturation (Spo₂) on LV twist in acute and chronic hypoxia and (2) elucidate whether endocardial versus epicardial mechanics respond differently to hypoxia.

METHODS

Twelve males (27±4 years) were tested near sea level in acute hypoxia (Spo₂=82±4%) and following 3 to 6 days at 5050 m (high altitude; Spo₂=83±3%). In both settings, participants received infusions of β₁-AR blocker esmolol and volume-matched saline (double-blind, randomized). LV mechanics were assessed with 2-dimensional speckle-tracking echocardiography, and region-specific analysis to compare subendocardial and subepicardial mechanics.

RESULTS

At sea level, compared with baseline (14.8±3.0°) LV twist was reduced with esmolol (11.2±3.3°; P=0.007) and augmented during hypoxia (19.6±4.9°; P<0.001), whereas esmolol+hypoxia augmented twist compared with esmolol alone (16.5±3.3°; P<0.001). At 5050 m, LV twist was increased compared with sea level (19.5±5.4°; P=0.004), and reduced with esmolol (13.0±3.8°; P<0.001) and Spo₂ normalization (12.8±3.4°; P<0.001). Moreover, esmolol+normalized Spo₂ lowered twist further than esmolol alone (10.5±3.1°; P=0.036). There was no mechanics-derived evidence of endocardial dysfunction with hypoxia at sea level or high altitude.

CONCLUSIONS

These findings suggest LV twist is augmented in hypoxia via β₁-AR-dependent and β₁-AR-independent mechanisms (eg, α₁-AR stimulation), but does not appear to reflect endocardial dysfunction.

Esmolol Infusion Reduces Blood Loss and Opiate Consumption during Fertility Preserving Myomectomy

Objectives

The objective of this study is to evaluate the effect of esmolol-induced hypotensive anesthesia (EIHA) on intra-operative (IO) bleeding during open myomectomy.

Patients and Methods

Eighty-eight women were randomly divided into the study group received EIHA without uterine tourniquet and control group who received normotensive anesthesia with uterine tourniquet. EIHA was provided as priming dose of esmolol (0.5 mg.kg^-1) before the induction of anesthesia and esmolol infusion (0.05-0.3 mg.kg^-1.min^-1) to maintain mean arterial pressure at 60-70 mmHg that was stopped on completion of myomectomy. Fentanyl was used as IO analgesia (loading dose: 1.0 μg.kg^-1 then infusion of 0.2-0.4 μg.kg^-1.h^-1). All patients received 6% hydroxyethyl starch (HES; initially, 3 mL.kg^-1 over 5-10 minutes and supplemental doses according to requirements) and Lactated Ringer's solution (LR; 5 mL.kg^-1.h^-1). Trigger for blood transfusion was hemoglobin concentration (HBC) <7 g.dL^-1. Study outcomes included the extent of postoperative (PO) HBC deficit in relation to preoperative HBC, frequency of tourniquet application for the study patients, and total fentanyl consumption.

Results

EIHA significantly reduced blood pressure measures since laryngoscopy and tracheal intubation till the end of surgery in the study group compared to control group. Eight study patients (18.9%) required tourniquet application for control of bleeding; however, amount of IO blood loss; total field visibility score and PO HBC deficit were non significantly lower in the study group. EIHA allowed significant reduction of the IO amount of LR and additional amounts of HES infusions. Study patients group consumed significantly lower IO fentanyl doses with significantly longer duration till the 1^st PO request and the number of additional fentanyl, and lower numeric rating scale scores in study group compared to controls.

Conclusion

Open myomectomy under EIHA is feasible and safe and allows fertility-sparing with minimal risk of blood transfusion. The applied procedure of EIHA allowed blunting of pressor reflexes secondary to LIT, surgical stresses and extubation, and allowed reduction of IO and PO opioid doses.

Esmolol Compared with Amiodarone in the Treatment of Recent-Onset Atrial Fibrillation (RAF): An Emergency Medicine External Validity Study

BACKGROUND

Recent-onset atrial fibrillation (RAF) is the most frequent supraventricular dysrhythmia in emergency medicine. Severely compromised patients require acute treatment with injectable drugs OBJECTIVE: The main purpose of this external validity study was to compare the short-term efficacy of esmolol with that of amiodarone to treat severe RAF in an emergency setting.

METHODS

This retrospective survey was conducted in mobile intensive care units by analyzing patient records between 2002 and 2013. We included RAF with (one or more) severity factors including: clinical shock, angina pectoris, ST shift, and very rapid ventricular rate. A blind matching procedure was used to constitute esmolol group (n = 100) and amiodarone group (n = 200), with similar profiles for age, gender, initial blood pressure, heart rate, severity factors, and treatment delay. The main outcome measure was the percentage of patients with a ventricular rate control defined as heart frequency ≤ 100 beats/min. More stringent (rhythm control) and more humble indicators (20% heart rate reduction) were analyzed at from 10 to 120 min after treatment initiation.

RESULTS

Patient characteristics were comparable for both groups: age 66 ± 16 years, male 71%, treatment delay < 1 h 36%, 1-2 h 29%, > 2 h 35%, chest pain 61%, ST shift 62%, ventricular rate 154 ± 26 beats/min, and blood pressure 126/73 mm Hg. The superiority of esmolol was significant at 40 min (64% rate control with esmolol vs. 25% with amiodarone) and for all indicators from 10 to 120 min after treatment onset.

CONCLUSION

In "real life emergency medicine," esmolol is better than amiodarone in the treatment of RAF.

Adjunctive therapies during veno-venous extracorporeal membrane oxygenation

Veno-venous extracorporeal membrane oxygenation (VV ECMO) restores gas exchanges in severely hypoxemic patients. The need for adjunctive therapies usually originates either from refractory hypoxemia during ECMO (defined as the persistence of low blood oxygen levels despite extracorporeal support) or from the attempt to give a specific therapy for acute respiratory distress syndrome (ARDS). In this review, therapeutic strategies to treat refractory and persistent hypoxemia during ECMO are evaluated. In the second part, therapies that can be added on top of VV ECMO to address inflammation and altered vascular permeability in ARDS are examined. The therapies currently available often allow for an effective treatment of hypoxemia during ECMO. ARDS is still lacking a specific therapy, with low-grade evidence sustaining the majority of currently used drugs.

Short-Term Treatment with Esmolol Reverses Left Ventricular Hypertrophy in Adult Spontaneously Hypertensive Rats via Inhibition of Akt/NF-κB and NFATc4

Our group has previously demonstrated that short-term treatment with esmolol reduces left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHRs). The present study aimed to assess the molecular mechanisms related to this effect. Fourteen-month-old male SHR_s were treated intravenously with saline as vehicle (SHR) or esmolol (SHR-E) (300 μg/kg/min). Age-matched vehicle-treated male Wistar-Kyoto (WKY) rats served as controls. After 48 hours of treatment, the hearts were harvested and left ventricular tissue was separated and processed for Western blot analysis to determine the levels of Akt, NF-κB, NFATc4, Creb1, Serca2a, Erk1/2, and Sapk/Jnk. Biomarkers of oxidative stress, such as catalase, protein carbonyls, total thiols, and total antioxidant capacity were evaluated. Esmolol reversed the levels of p-NFATc4, p-Akt, and p-NF-κB in SHRs to the phospholevels of these proteins in WKY rats without modifying p-Erk1/2, p-Sapk/Jnk, p-Creb1, or Serca2a in SHR. Compared with SHR, esmolol increased catalase activity and reduced protein carbonyls without modifying total thiols or total antioxidant capacity. Short-term treatment with esmolol reverses LVH in aged SHRs by downregulation of Akt/NF-κB and NFATc4 activity. Esmolol treatment also increases catalase activity and reduces oxidative stress in SHRs with LVH.

Esmolol infusion versus propranolol infusion: effects on heart rate and blood pressure in healthy volunteers

Despite its widespread clinical use, the β1-adrenergic receptor antagonist esmolol hydrochloride is not commonly used in human physiology research, and the effective dose of esmolol (compared with the nonselective β-blocker propranolol) is unclear. In four separate studies we used cycle ergometry exercise and infusions of isoproterenol and epinephrine to test the heart rate (HR)-lowering effect of esmolol compared with propranolol and saline in healthy humans. In cohort 1, both esmolol (ΔHR 57 ± 6 beats/min) and propranolol (ΔHR 56 ± 7 beats/min) attenuated exercise tachycardia compared with saline (ΔHR 88 ± 17 beats/min). In cohort 2, we found that the HR response to exercise was similar at 5 min (ΔHR 57 ± 9 beats/min) and 60 min (ΔHR 55 ± 9 beats/min) after initiation of the esmolol maintenance infusion. In cohort 3, we confirmed that the HR-lowering effect of esmolol disappeared 45 min after termination of the maintenance infusion. In cohort 4, changes in femoral blood flow and hematological parameters in response to epinephrine infusion were not different between esmolol and saline infusion, indicating that our esmolol infusion paradigm does not block β2-receptors. Collectively, our data indicate that infusion of ~160 mg of esmolol (range 110-200 mg in the 5 min before exercise) acutely and selectively blocks β1-receptors in healthy humans. Additionally, β1-receptors remain blocked 60 min later if a maintenance infusion of ~0.2 mg·kg total body mass-1·min-1 continues. The current data lay the foundation for future studies to evaluate β1- vs. β2-receptor control of the circulation in humans.NEW & NOTEWORTHY We used cycle ergometry exercise and infusions of isoproterenol and epinephrine to test the heart rate-lowering effect of esmolol compared with propranolol and saline in healthy humans. Collectively, our data indicate that infusion of ~160 mg of esmolol (range 110-200 mg in the 5 min before exercise) acutely and selectively blocks β1-adrenergic receptors. These infusion parameters can be used in future experiments to evaluate β1- vs. β2-receptor control of the circulation in humans.

Early regression of coronary artery remodeling with esmolol and DDAH/ADMA pathway in hypertensive rats

Our preclinical study demonstrated that esmolol produces early regression of left ventricular hypertrophy in arterial hypertension. The aim of this study was to assess the effects of short-term esmolol therapy on the regression of left anterior descending artery remodeling in spontaneously hypertensive rats (SHRs), and to determine whether the asymmetric dimethylarginine (ADMA)/dimethylarginine dimethylaminohydrolase (DDAH) pathway, a regulator of nitric oxide (NO) bioavailability, accounted for this regression. Fourteen-month-old male SHRs were treated intravenously with vehicle (SHR, n=15) or esmolol (SHR-E, n=20) (300 μg kg^-1 min^-1). Age-matched, vehicle-treated male Wistar-Kyoto rats (WKY, n=15) served as controls. SHRs were also treated with nitroglycerin (SHR-N, n=5). After 48 h, the left anterior descending artery structure and morphology were assessed, and dose-response curves for 5-hydroxytryptamine (5-HT, 10^-9-3 × 10^-5 mol l^-1) were constructed. ADMA concentrations in plasma and left ventricle and DDAH activity in tissue were analyzed. Wall thickness and cross-sectional area were significantly lower after treatment with esmolol in SHR-E than in SHR. Media thickness and smooth muscle cell count were lower in SHR-E than in SHR. Esmolol induced a significant reduction in adventitial cell count in SHR-E. The area under the concentration-response curves was significantly higher in SHR than in SHR-E, as were the esmolol normalized coronary artery contracting responses to 5-HT. We found significantly lower ADMA levels and significantly higher DDAH activity in the ventricle in SHR-E than in SHR. The protective effect of esmolol on the regression of left anterior descending artery remodeling may be related to the reduction in ADMA levels.

β1-Blockade increases maximal apnea duration in elite breath-hold divers

We hypothesized that the cardioselective β₁-adrenoreceptor antagonist esmolol would improve maximal apnea duration in elite breath-hold divers. In elite national-level divers (n = 9), maximal apneas were performed in a randomized and counterbalanced order while receiving either iv esmolol (150 μg·kg^-1·min^-1) or volume-matched saline (placebo). During apnea, heart rate (ECG), beat-by-beat blood pressure, stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were measured (finger photoplethysmography). Myocardial oxygen consumption (MV̇o₂) was estimated from rate pressure product. Cerebral blood flow through the internal carotid (ICA) and vertebral arteries (VA) was assessed using Duplex ultrasound. Apnea duration improved in the esmolol trial when compared with placebo (356 ± 57 vs. 323 ± 61 s, P < 0.01) despite similar end-apnea peripheral oxyhemoglobin saturation (71.8 ± 10.3 vs. 74.9 ± 9.5%, P = 0.10). The HR response to apnea was reduced by esmolol at 10-30% of apnea duration, whereas MAP was unaffected. Esmolol reduced SV (main effect, P < 0.05) and CO (main effect; P < 0.05) and increased TPR (main effect, P < 0.05) throughout apnea. Esmolol also reduced MV̇o₂ throughout apnea (main effect, P < 0.05). Cerebral blood flow through the ICA and VA was unchanged by esmolol at baseline and the last 30 s of apnea; however, global cerebral blood flow was reduced in the esmolol trial at end-apnea (P < 0.05). Our findings demonstrate that, in elite breath-hold divers, apnea breakpoint is improved by β₁-blockade, likely owing to an improved total body oxygen sparring through increased centralization of blood volume (↑TPR) and reduced MV̇o₂NEW & NOTEWORTHY The governing bodies for international apnea competition, the Association Internationale pour le Développment de l'Apnée and La Confédération Mondaile des Activités Subaquatiques, have banned the use of β-blockers based on anecdotal reports that they improve apnea duration. Using a randomized placebo-controlled trial, we are the first to empirically confirm that β-blockade improves apnea duration. This improvement in apnea duration coincided with a reduced myocardial oxygen consumption.

Variable cost of ICU care, a micro-costing analysis

Intensive care unit (ICU) costs account for a great part of a hospital's expenses. The objective of the present study was to measure the patient-specific cost of ICU treatment, to identify the most important cost drivers in ICU and to examine the role of various contributing factors in cost configuration. A retrospective cost analysis of all ICU patients who were admitted during 2011 in a Greek General, seven-bed ICU and stayed for at least 24hours was performed, by applying bottom-up analysis. Data collected included demographics and the exact cost of every single material used for patients' care. Prices were yielded from the hospital's purchasing costs and from the national price list of the imaging and laboratory tests, which was provided by the Ministry of Health. A total of 138 patients were included. Variable cost per ICU day was €573.18. A substantial cost variation was found in the total costs obtained for individual patients (median: €3443, range: €243.70-€116,355). Medicines were responsible for more than half of the cost and antibiotics accounted for the largest part of it, followed by blood products and cardiovascular drugs. Medical cause of admission, severe illness and increased length of stay, mechanical ventilation and dialysis were the factors associated with cost escalation. ICU variable cost is patient-specific, varies according to each patient's needs and is influenced by several factors. The exact estimation of variable cost is a pre-requisite in order to control ICU expenses.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Antihypertensives

OBJECTIVE

Hypertension remains a common condition in pediatric cardiac intensive care. The physiologic effects of hypertension in this population are complex and are impacted by patient age, comorbidities, and primary cardiac disease. The objective of this study is to review current pharmacotherapies for the management of systemic hypertension in the pediatric cardiac ICU.

DATA SOURCES

Relevant literature to the treatment of systemic hypertension in children was included. Specific focus was given to literature studying the use of therapies in critically ill children and those with heart disease. Reference textbooks and drug packaging inserts were used for drug-specific pediatric guidelines.

STUDY SELECTION

A search of MEDLINE, PubMed, and the Cochrane Database was performed to find literature about the management of hypertension in children. Metaanalyses and pediatric-specific studies were primarily considered and cross-referenced. Pertinent adult studies were included.

DATA EXTRACTION

Once the studies for inclusion were finalized, priority for data extraction was given to pediatric-specific studies that focused on children with heart disease and critical illness.

CONCLUSIONS

Systemic hypertension is common, and there is significant heterogeneity in the patient population with critical heart disease. There are limited large, prospective analyses of safety and efficacy for pediatric drug antihypertensive agents. Despite patient heterogeneity, most pharmacotherapies are safe and efficacious.

Management of refractory hypoxemia during venovenous extracorporeal membrane oxygenation for ARDS

Venovenous extracorporeal membrane oxygenation (VV ECMO) in acute respiratory distress syndrome (ARDS) is currently a widely used therapeutic strategy. However, patients are often still hypoxemic despite complete ECMO support. The major determinants of peripheral oxygen saturation (SpO2) during VV ECMO are pump flow, degree of recirculation, patient's systemic venous return and its oxygen saturation, hemoglobin concentration and residual lung function. Current guidelines state that the support can be considered adequate when the patient's SpO2 is equal or greater than 80%, but a possible objection could be that such a value of O2-tension may be too low and may worsen the patient's prognosis. Moving from the pathophysiology of hypoxemia during VV ECMO, this review focuses on recirculation of blood and on the possible strategies to minimize it, on the pharmacologic modulation of intrapulmonary shunt and on the questions related to management of ECMO flow and the risks and benefits of permissive hypoxemic states. Transfusional strategy during VV ECMO, administration of neuromuscular blocking agents and sedatives, therapeutic hypothermia, and prone positioning is also reviewed. The potential advantages of β-blockers are discussed. Finally, transition from VV ECMO to venoarterial ECMO (VA ECMO) or a hybrid configuration is also examined.

Does the ADMA/DDAH/NO pathway modulate early regression of left ventricular hypertrophy with esmolol?

Hypertensive left ventricular hypertrophy (LVH) is a maladaptive response to chronic pressure overload and a strong independent risk factor for cardiovascular disease. Regression of LVH is associated with improved prognosis. Regression of LVH with antihypertensive therapy (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, calcium channel blockers, and diuretics) has been reported, although only after long-term treatment. Asymmetrical dimethylarginine (ADMA), the most potent endogenous NO synthase inhibitor, is emerging as an important cardiovascular risk factor in patients with arterial hypertension and LVH, and dimethylarginine dimethylaminohydrolase (DDAH) is the mechanism that most frequently leads to accumulation of ADMA (plasma ADMA is cleared in small part by renal excretion, although the bulk of ADMA is degraded by DDAH). Left ventricular mass is strongly modulated by the NO system. As an important inhibitor of the bioavailability of NO, ADMA is an underlying mechanism of LVH. Beta-blockers can induce regression of LVH and reduced plasma ADMA levels. Oxidative stress is increased in patients with LVH, and this in turn increases generation of ADMA. In a previous preclinical study of spontaneously hypertensive rats, we found that short-term treatment (48 h) with esmolol reverses early LVH, increases the bioavailability of NO, and improves antioxidant status in plasma. Therefore, we propose that the ADMA/DDAH/NO pathway could modulate early regression of LVH with esmolol.

Efficacy and Safety of Landiolol Compared to Amiodarone for the Management of Postoperative Atrial Fibrillation in Intensive Care Patients

OBJECTIVE

The authors assessed the efficacy and safety of landiolol, an ultra-short-acting beta-blocker, with those of amiodarone in the restoration of sinus rhythm for postoperative atrial fibrillation (POAF) in intensive care unit (ICU) patients.

DESIGN

A retrospective data analysis.

SETTING

Data were collected from patients admitted to the ICU in a single university hospital between 2012 and 2015.

PARTICIPANTS

Records of a total of 276 patients who developed POAF after ICU admission were collected from hospital records.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Treatment success was defined as restoration of sinus rhythm without concomitant therapy within 24 hours of treatment and lasting for more than an hour. The landiolol dosage was in the range of 0.7 µg/kg/min-to-2.5 µg/kg/min. The authors compared a total of 55 patients with POAF who received either landiolol (n = 32) or intravenous amiodarone (n = 23) in the ICU. The major findings were that the median time required for conversion to sinus rhythm was shorter in landiolol patients compared with amiodarone patients (75 v 150 min respectively, p = 0.0355). However, treatment success rates did not differ significantly after 24 hours (odds ratio 1.25, 95% confidence interval 0.17-9.09, p = 0.60). Adverse events with bradycardia leading to drug discontinuation were seen only in the patients receiving amiodarone (n = 3, p = 0.032).

CONCLUSIONS

Landiolol achieved swift and safe restoration of sinus rhythm in ICU patients with POAF and could be considered as a favorable drug choice over amiodarone in such patients.

Beta-blockers in septic shock: a review

In septic shock, high adrenergic stress is associated with cardiovascular and systemic adverse effects, which can negatively affect the results. Beta-adrenergic receptor block has been shown to be effective in controlling the disproportionate increase in heart rate, maintaining a favorable hemodynamic profile and apparently improving the efficiency of the cardiovascular system in order to maintain tissue perfusion. They have also been shown to modulate favorably catecholamine-induced immunosuppression and to decrease insulin resistance, protein catabolism, and proinflammatory cytokine expression associated with cardiovascular dysfunction. Selective beta-1 blockers appear to provide better results than non-selective blockers, even suggesting a positive impact on mortality. Future clinical trials are still needed to confirm these findings and define the scope of their benefits.

Effects of lidocaine and esmolol infusions on hemodynamic changes, analgesic requirement, and recovery in laparoscopic cholecystectomy operations

OBJECTIVE

We compared the effects of lidocaine and esmolol infusions on intraoperative hemodynamic changes, intraoperative and postoperative analgesic requirements, and recovery in laparoscopic cholecystectomy surgery.

METHODS

The first group (n=30) received IV lidocaine infusions at a rate of 1.5mg/kg/min and the second group (n=30) received IV esmolol infusions at a rate of 1mg/kg/min. Hemodynamic changes, intraoperative and postoperative analgesic requirements, and recovery characteristics were evaluated.

RESULTS

In the lidocaine group, systolic arterial blood pressures values were lower after the induction of anesthesia and at 20min following surgical incision (p<0.05). Awakening time was shorter in the esmolol group (p<0.001); Ramsay Sedation Scale scores at 10min after extubation were lower in the esmolol group (p<0.05). The modified Aldrete scores at all measurement time points during the recovery period were relatively lower in the lidocaine group (p<0.05). The time to attain a modified Aldrete score of ≥9 points was prolonged in the lidocaine group (p<0.01). Postoperative resting and dynamic VAS scores were higher in the lidocaine group at 10 and 20min after extubation (p<0.05, p<0.01, respectively). Analgesic supplements were less frequently required in the lidocaine group (p<0.01).

CONCLUSION

In laparoscopic cholecystectomies, lidocaine infusion had superiorities over esmolol infusions regarding the suppression of responses to tracheal extubation and postoperative need for additional analgesic agents in the long run, while esmolol was more advantageous with respect to rapid recovery from anesthesia, attenuation of early postoperative pain, and modified Aldrete recovery (MAR) scores and time to reach MAR score of 9 points.

Short-term esmolol improves coronary artery remodeling in spontaneously hypertensive rats through increased nitric oxide bioavailability and superoxide dismutase activity

The aim of this study was to assess the effects of short-term esmolol therapy on coronary artery structure and function and plasma oxidative stress in spontaneously hypertensive rats (SHR). For this purpose, 14-month-old male SHR were treated for 48 hours with esmolol (SHR-E, 300 μg/kg/min). Age-matched untreated male SHR and Wistar Kyoto rats (WKY) were used as hypertensive and normotensive controls, respectively. At the end of intervention we performed a histological study to analyze coronary artery wall width (WW), wall-to-lumen ratio (W/L), and media cross-sectional area (MCSA). Dose-response curves for acetylcholine (ACh) and sodium nitroprusside were constructed. We also assessed several plasma oxidative stress biomarkers, namely, superoxide scavenging activity (SOSA), nitrites, and total antioxidant capacity (TAC). We observed a significant reduction in WW (P < 0.001), W/L (P < 0.05), and MCSA (P < 0.01) and improved endothelium-dependent relaxation (AUC_SHR-E = 201.2 ± 33 versus AUC_SHR = 97.5 ± 21, P < 0.05) in SHR-E compared with untreated SHR; no differences were observed for WW, MCSA, and endothelium-dependent relaxation by ACh at higher concentrations (10⁻⁶ to 10⁻⁴ mol/l) for SHR-E with respect to WKY. SOSA (P < 0.001) and nitrite (P < 0.01) values were significantly higher in SHR-E than in untreated SHR; however, TAC did not increase after treatment with esmolol. Esmolol improves early coronary artery remodeling in SHR.

Autonomic modulation of repolarization instability in patients with heart failure prone to ventricular tachycardia

QT variability (QTV) signifies repolarization lability, and increased QTV is a risk predictor for sudden cardiac death. The aim of the present study was to investigate the role of autonomic nervous system activity on QTV. This study was performed in 29 subjects: 10 heart failure (HF) patients with spontaneous ventricular tachycardia [HFVT(+)], 10 HF patients without spontaneous VT [HFVT(-)], and 9 subjects with structurally normal hearts (HNorm). The beat-to-beat QT interval was measured on 3-min records of surface ECGs at baseline and during interventions (atrial pacing and esmolol, isoprenaline, and atropine infusion). Variability in QT intervals was expressed as the SD of all QT intervals (SDQT). The ratio of the SDQT to SD of RR intervals (SDRR) was calculated as an index of QTV normalized to heart rate variability. There was a trend toward a higher baseline SDQT-to-SDRR ratio in the HFVT(+) group compared with the HFVT(-) and HNorm groups (P = 0.09). SDQT increased significantly in the HFVT(+) and HFVT(-) groups compared with the HNorm group during fixed-rate atrial pacing (P = 0.008). Compared with baseline, isoprenaline infusion increased SDQT in HNorm subjects (P = 0.02) but not in HF patients. SDQT remained elevated in the HFVT(+) group relative to the HNorm group despite acute β-adrenoceptor blockade with esmolol (P = 0.02). In conclusion, patients with HF and spontaneous VT have larger fluctuations in beat-to-beat QT intervals. This appears to be a genuine effect that is not solely a consequence of heart rate variation. The effect of acute autonomic nervous system modulation on QTV appears to be limited in HF patients.