Symptomatic Supraventricular Tachycardia Resistant to Adenosine Therapy in a Patient with Chronic Theophylline Use

Theophylline is a potent adenosine receptor antagonist with indirect adrenergic effects that can lead to arrhythmias and metabolic abnormalities such as hypokalemia. Therapeutic toxicity cases have declined over the years mainly due to decreased recommended therapeutic doses and overall decreased usage of this medication due to newer available COPD treatment options. We present a clinical case of symptomatic supraventricular tachycardia resistant to adenosine therapy in a patient with theophylline use. This case highlights the importance of comprehensive medication review in acute settings to aid in identifying the underlying etiologies and initiating prompt treatments. It also signifies the importance of reviewing chronic medications in each outpatient visits to ensure continued indication for their use and be able to change them to newer agents per guidelines whenever possible.

Coronary artery spasm following dobutamine stress echocardiogram

A 53-year-old woman with atypical chest pain underwent a dobutamine stress echocardiogram (DSE) and developed a coronary spasm (CS) with severe pain and dramatic ST-segment elevation 9 min after dobutamine infusion was discontinued. The spasm resolved after sublingual nitroglycerin administration. The same-day coronary angiogram showed non-significant stenosis in the three coronary territories. Retrospectively, we found that the patient had vasospastic angina (VSA), a condition that has been strongly associated with the development of dobutamine-induced CS. Mechanisms of dobutamine-induced CS are not fully understood and include endothelial dysfunction leading to deficient nitric oxide-mediated coronary vasodilation in response to increased myocardial oxygen demand as well as imbalance between β1 and β2 adrenergic effects of dobutamine. Dobutamine-induced CS has also been much more frequently reported in patients from Asian descent with VSA. VSA should be systemically recognised in patients considered for DSE and, if present, other modalities of stress imaging should be discussed.

EFFECT OF A SINGLE TRANSCRANIAL STIMULATION ON THE RECOVERY OF SKI-RACERS

Aim. The article deals with assessing the effect of a single transcranial stimulation with impulse current on the recovery of ski-racers. Materials and methods. 18 skiers aged 20 ± 2 (skiers of the first rank or that of Candidate of Master of Sport) participated in the study. Skiing for 3 was used as a special load. To achieve the purpose of the study, we used the method of transcranial stimulation with impulse current after load. Results. During a single transcranial stimulation after a special load by the 20th minute, there is a statistically significant reduction of the urgent recovery of heart rate (HR), minute blood volume (MBV), the Robinson index (RI), the chronotropic index (CI). The time for the recovery of vegetative homeostasis also reduces. Conclusion. A single transcranial stimulation accelerates the recovery of the cardiovascular system in ski-racers by reducing the adrenergic effects of the autonomic nervous system. The efficiency of using transcranial stimulation is associated with individual-typological features of the vegetative regulation in athletes.

The Efficacy and Safety of Norepinephrine and Its Feasibility as a Replacement for Phenylephrine to Manage Maternal Hypotension during Elective Cesarean Delivery under Spinal Anesthesia

Maternal hypotension commonly occurs during spinal anesthesia for cesarean delivery, with a decrease of systemic vascular resistance recognized as a significant contributor. Accordingly, counteracting this effect with a vasopressor that constricts arterial vessels is appropriate, and the pure α-adrenergic receptor agonist phenylephrine is the current gold standard for treatment. However, phenylephrine is associated with dose-dependent reflex bradycardia and decreased cardiac output, which can endanger the mother and fetus in certain circumstances. In recent years, the older, traditional vasopressor norepinephrine has attracted increasing attention owing to its mild β-adrenergic effects in addition to its α-adrenergic effects. We search available literature for papers directly related to norepinephrine application in spinal anesthesia for elective cesarean delivery. Nine reports were found for norepinephrine use either alone or compared to phenylephrine. Results show that norepinephrine efficacy in rescuing maternal hypotension is similar to that of phenylephrine without obvious maternal or neonatal adverse outcomes, and with a lower incidence of bradycardia and greater cardiac output. In addition, either computer-controlled closed loop feedback infusion or manually-controlled variable-rate infusion of norepinephrine provides more precise blood pressure management than equipotent phenylephrine infusion or norepinephrine bolus. Thus, based on the limited available literature, norepinephrine appears to be a promising alternative to phenylephrine; however, before routine application begins, more favorable high-quality studies are warranted.

Vasopressors in critical illness

Vasopressors are used in various shock states to correct hypotension, aiming at restoring or improving organ and tissue perfusion. Vasopressor therapy may be associated with excessive vasoconstriction, but also metabolic and other side-effects. Hence, the ideal target for arterial pressure remains undetermined. Adrenergic agents remain the most commonly used vasopressor agents. Adrenergic agents increase arterial pressure through stimulation of alpha-adrenergic receptors. The effects of the different adrenergic agents differ mostly due to variable associated beta-adrenergic effects. Epinephrine and norepinephrine are strong and equipotent vasopressor agents. Their impact on outcome is as yet unanswered, but there is no sign that epinephrine might be associated with better outcomes. Accordingly, norepinephrine is the adrenergic agent of choice, especially in patients with cardiogenic shock. Vasopressin is a non-adrenergic vasopressor acting via V1 receptor stimulation, with weak vasopressor effects in normal conditions, but markedly increased vascular tone in shock states, especially in septic shock. Splanchnic vasoconstriction may occur. Arginine vasopressin at low doses appears to be a promising alternative to adrenergic agents, but its exact place is not yet well defined.