Suxamethonium and critical illness polyneuropathy

Suxamethonium-Induced Hyperkalemia: A Short Review of Causes and Recommendations for Clinical Applications

After the introduction of suxamethonium in 1953, cases of cardiac arrest during induction of anesthesia were recorded. In the following years, hyperkalemia was identified as the cause, and the connection to acetylcholine receptor modulation as the underlying molecular mechanism was made. Activation of the acetylcholine receptor with suxamethonium, acetylcholine, or choline causes an efflux of potassium to the extracellular space. However, certain pathological conditions cause acetylcholine receptor proliferation and the emergence of immature receptors capable of a larger potassium efflux to the bloodstream. These pathologic conditions include upper and lower neuron injuries, major burns, trauma, immobility, muscle tumors, muscular dystrophy, and prolonged critical illness. The latter is more important and relevant than ever due to the increasing number of COVID-19 patients requiring prolonged respiratory support and consequent immobilization. Suxamethonium can be used safely in the vast majority of patients. Still, reports of lethal hyperkalemic responses to suxamethonium continue to emerge. This review serves as a reminder of the pathophysiology behind extensive potassium release. Proficiency in the use of suxamethonium includes identification of patients at risk, and selection of an alternative neuromuscular blocking agent is imperative.

Copper and anesthesia: clinical relevance and management of copper related disorders

Recent research has implicated abnormal copper homeostasis in the underlying pathophysiology of several clinically important disorders, some of which may be encountered by the anesthetist in daily clinical practice. The purpose of this narrative review is to summarize the physiology and pharmacology of copper, the clinical implications of abnormal copper metabolism, and the subsequent influence of altered copper homeostasis on anesthetic management.

[Changes in kaliemia following rapid sequence induction with succinylcholine in critically ill patients]

OBJECTIVE

Evaluate the changes in potassium following rapid sequence induction with succinylcholine in critically ill-patients and determine whether hospital length of stay could influence the succinylcholine-induced hyperkaliemia.

STUDY DESIGN

Prospective and observational study.

PATIENTS AND METHODS

After approval by our local ethical committee, we prospectively included 36 patients admitted from more than 24hours in ICU and who required succinylcholine for rapid tracheal intubation (1mg/kg). Serum potassium was measured before, 5 and 30min after succinylcholine. The incidence of life-threatening hyperkaliemia (≥6.5mmol/L) was noted.

RESULTS

We could observe significant and transient increase in serum potassium (median increase of 0.45 [0.20-0.80] mmol/L at five minutes). A significant relationship was observed between the ICU length of stay and arterial potassium increase (r=0.37, P<0.05). From the ROC curve, a threshold of 12 days had an 86% sensitivity and 69% specificity in discriminating patients in whom the potassium increase was more than 1.5mmol/L.

CONCLUSION

Induction with succinylcholine is followed by significant but transient hyperkaliema. The ICU length of stay before giving succinylcholine could influence significantly the amplitude of potassium increase.

Critical illness neuromuscular syndromes

Critical illness neuromyopathy (CINM) is the most common peripheral neuromuscular disorder encountered in the ICU. Bilateral diffuse weakness predominant in the proximal part of the limbs after improvement of the acute phase of the critical illness is highly suggestive of CINM. Although muscle and peripheral nerve are often involved in combination, muscle involvement alone is increasingly identified on electrophysiologic investigation, including direct muscle stimulation. Respiratory weakness results in delayed weaning and prolonged mechanical ventilation. Besides muscle immobilization and prolonged sepsis-induced multiorgan failure, which are risk factors for CINM, hyperglycemia and use of corticosteroids might have a deleterious effect on the neuromuscular system in critically ill patients.

Hyperkalemia and cardiac arrest following succinylcholine administration in a 16-year-old boy with acute nonlymphoblastic leukemia and sepsis

OBJECTIVES

To report a case of potentially lethal hyperkalemia related to succinylcholine administration.

DESIGN

Case report.

SETTING

A 13-bed pediatric intensive care unit in a tertiary level, university-based children's hospital.

PATIENT

A 16-yr-old boy treated in the intensive care unit due to Klebsiella pneumoniae sepsis, which developed after chemotherapy for nonlymphoblastic leukemia.

INTERVENTIONS

After admission to the intensive care unit, the patient required intubation (uneventful under ketamine and succinylcholine) and mechanical ventilation. On the 15th day of therapy, when his respiratory variables improved significantly, he was extubated. His cardiac rhythm, respiratory rate, arterial blood pressure, and hemoglobin oxygen saturation were continuously monitored. Several hours later, however, he required reintubation due to respiratory insufficiency. For intubation, precurarization with pancuronium, ketamine, propofol, and succinylcholine was used.

MEASUREMENTS AND MAIN RESULTS

Before and immediately after reintubation, serum potassium levels were measured. Two minutes after intubation, premature ventricular contractions, ventricular fibrillation, bradycardia, and finally cardiac arrest were recognized. An increase of serum potassium from 3.19 to 8.64 mmol/L was observed in arterial blood. The patient was immediately resuscitated with chest compressions, intravenous adrenaline, atropine, lidocaine, and sodium bicarbonate. Potassium values normalized within 30 mins. Further treatment in the intensive care unit was uneventful, and the patient was weaned from mechanical ventilation and discharged to a hematology clinic. At present his mental and physical state is satisfactory.

CONCLUSIONS

Succinylcholine may cause dangerous arrhythmias in septic and immobilized children. The alternative nondepolarizing agents should be used in such cases.

Airway Management in Critical Illness

Airway management in the ICU can be complicated due to many factors including the limited physiologic reserve of the patient. As a consequence, the likelihood of difficult mask ventilation and intubation increases. The incidence of failed airways and of cardiac arrest related to airway instrumentation in the ICU is much higher than that of elective intubations performed in the operating room. A thorough working knowledge of the devices available for the management of the difficult airway and recommended rescue strategies is paramount in avoiding bad patient outcomes. In this review, we will provide a conceptual framework for airway assessment, with an emphasis on assessment of the patient with limited cervical spine movement or injury and of morbidly obese patients. Furthermore, we will review the devices that are available for airway management in the ICU, and discuss controversies surrounding interventions like cricoid pressure and the use of muscle relaxants in the critically ill patient. Finally, strategies for the safe extubation of patients with known difficult airways will be provided.

Critical Illness Neuromuscular Syndromes

Critical illness neuromyopathy (CINM) is the most common peripheral neuromuscular disorder encountered in the ICU. Bilateral diffuse weakness predominant in the proximal part of the limbs after improvement of the acute phase of the critical illness is highly suggestive of CINM. Although muscle and peripheral nerve often are involved in combination, muscle involvement alone increasingly is identified on electrophysiological investigation, including direct muscle stimulation. Respiratory muscles also are involved, and CINM may cause delayed weaning and prolonged MV. Besides muscle immobilization and prolonged sepsis-induced multiple organ failure, which are both strong contributors to CINM, hyperglycemia and use of corticosteroids also might have a deleterious effect on the neuromuscular system in critically ill patients.

Paresis following mechanical ventilation

PURPOSE OF REVIEW

To review the medical literature on neuromuscular abnormalities acquired in the intensive care unit (ICU), particularly after mechanical ventilation, focusing on the most recent advances in this field.

RECENT FINDING

Using a simple bedside muscle strength score, significant clinical weakness is detected in one fourth of patients awakening in ICU after more than 1 week of mechanical ventilation. Weakness is associated with a longer time on mechanical ventilation, although the exact relationship between limb and respiratory neuromuscular involvement remains unclear. Muscle involvement is often combined with axonal involvement and can predominate or occur in isolation in some patients. Although prolonged severe weakness is unusual, milder abnormalities may persist for several months after discharge. In addition to severity and duration of initial organ failures, both neuromuscular inactivity and use of corticosteroids make an independent contribution of the neuromuscular abnormalities. Conversely, strict glycemic control may prevent neuromuscular abnormalities, although this needs to be confirmed in general ICU patients.

SUMMARY

Avoiding complete neuromuscular inactivity, using corticosteroids with greater discernment, and closely monitoring blood glucose levels might be worthwhile avenues for research in prevention of neuromuscular abnormalities acquired in the most severely ill ICU patients. Investigations of the severity of the respiratory neuromuscular involvement are also warranted.

Critical illness polyneuropathy

Critical illness polyneuropathy (CIP) is a syndrome that was first extensively described in the early 1980s, mainly in patients with failure to wean from mechanical ventilation. The syndrome is further characterized by limb muscle weakness, usually more pronounced distally than proximally, and is often accompanied by atrophy. The facial musculature is often strikingly spared. Reduced or absent deep-tendon reflexes and loss of peripheral sensation to light touch and pin prick often accompany the syndrome. Involvement of the phrenic nerve has been shown to further contribute to delayed weaning from the ventilator in many patients. The electrophysiologic studies are consistent with a predominantly motor and, often to a lesser extent, sensory axonal polyneuropathy. The incidence of CIP is high, with often more than 50% of patients in major medical and surgical critical care units suffering from the syndrome. The systemic inflammatory response syndrome (SIRS) is strongly associated with CIP and, among the multiorgan failure often seen in SIRS, CIP is thought to represent a neurologic manifestation of SIRS. The neurologic effects of SIRS are thought to be mediated by released mediators like cytokines and free radicals, affecting the microcirculation of the central and peripheral nervous system. Examination of the peripheral nervous system is often unreliable, and the only way to establish a definitive diagnosis is by performing electrophysiologic studies. Morbidity and mortality rates are high. If the underlying problem causing sepsis and/or SIRS can be treated successfully, full recovery from CIP can occur. This recovery often occurs in a matter of weeks in milder cases and in months in more severe cases. Knowledge of CIP is essential for intensivists and other specialists who care for critically ill patients. This review summarizes the current available literature on this topic.

Critical illness polyneuropathy

Critical illness polyneuropathy is a self-limited acute axonal neuropathy that develops during treatment of severely ill patients and remits spontaneously once the critical condition is under control. Clinical manifestations include muscle weakness and atrophy, delayed weaning from the respirator, and prolongation of the mobilization phase. The pathogenesis is not understood in detail but most authors assume that the inflammatory cascade that mediates the systemic inflammatory response and multiple organ failure play a pivotal role. This review summarizes current knowledge of this common neuropathic complication during intensive care treatment.

Management of the septic patient in the operating room

Sepsis, severe sepsis, and septic shock represent the spectrum of physiological response to a variety of infecting pathogens. Multiple-organ dysfunction may result from widespread activation of inflammatory and antiinflammatory mechanisms. Intensive multiorgan support, effective antibiotic therapy, and eradication of the inciting source remain the cornerstones in the care of septic patients. Perioperative planning and management need to ensure the continuation of such care in addition to providing for the requirements of the given surgical procedure.