Esmolol indirectly stimulates vagal nerve activity in endotoxemic pigs

Protocol Study for the Evaluation of Non-Opioid Balanced General Anaesthesia in Cardiac Surgery with Cardiopulmonary Bypass: A Randomised, Controlled, Multicentric Superiority Trial (OFACAR Study)

Opioid-free anaesthesia (OFA) is general anaesthesia based on the use of several non-opioid molecules that aim to have an analgesic effect, decrease the sympathetic response, decrease hormonal stress, and decrease the inflammatory response during surgery. Although this approach to anaesthesia is regularly used in clinical practice, it remains a novel approach. The literature on this anaesthesia modality finds a number of positive effects on cardiac, respiratory, and cognitive function but no randomised study evaluated these effects during cardiac surgery where there is a high incidence of postoperative complications. The main aim of the study is to compare OFA vs. standard balanced opioid general anaesthesia on the incidence of postoperative complications and the length of stay in intensive care and hospital. OFACAR is a multicentric, randomised, controlled, superiority, single-blind, two parallel-arm clinical trial in patients undergoing cardiac surgery with cardiopulmonary bypass. We compared a balanced general anaesthesia without opioids (OFA group) vs. a balanced opioid general anaesthesia with sufentanil (control group). One hundred and sixty patients will be enrolled in each treatment group. The primary endpoint is a composite one which corresponds to the occurrence of at least one of the postoperative complications, defined according to European standards within 30 days after surgery. Recruitment started in September 2019, and data collection is expected to end in November 2024.

The autonomic nervous system in septic shock and its role as a future therapeutic target: a narrative review

The autonomic nervous system (ANS) regulates the cardiovascular system. A growing body of experimental and clinical evidence confirms significant dysfunction of this regulation during sepsis and septic shock. Clinical guidelines do not currently include any evaluation of ANS function during the resuscitation phase of septic shock despite the fact that the severity and persistence of ANS dysfunction are correlated with worse clinical outcomes. In the critical care setting, the clinical use of ANS-related hemodynamic indices is currently limited to preliminary investigations trying to predict and anticipate imminent clinical deterioration. In this review, we discuss the evidence supporting the concept that, in septic shock, restoration of ANS-mediated control of the cardiovascular system or alleviation of the clinical consequences induced by its dysfunction (e.g., excessive tachycardia, etc.), may be an important therapeutic goal, in combination with traditional resuscitation targets. Recent studies, which have used standard and advanced monitoring methods and mathematical models to investigate the ANS-mediated mechanisms of physiological regulation, have shown the feasibility and importance of monitoring ANS hemodynamic indices at the bedside, based on the acquisition of simple signals, such as heart rate and arterial blood pressure fluctuations. During the early phase of septic shock, experimental and/or clinical studies have shown the efficacy of negative-chronotropic agents (i.e., beta-blockers or ivabradine) in controlling persistent tachycardia despite adequate resuscitation. Central α-2 agonists have been shown to prevent peripheral adrenergic receptor desensitization by reducing catecholamine exposure. Whether these new therapeutic approaches can safely improve clinical outcomes remains to be confirmed in larger clinical trials. New technological solutions are now available to non-invasively modulate ANS outflow, such as transcutaneous vagal stimulation, with initial pre-clinical studies showing promising results and paving the way for ANS modulation to be considered as a new potential therapeutic target in patients with septic shock.

Autonomic nervous system activity and the risk of nosocomial infection in critically ill patients with brain injury

PURPOSE

Nosocomial infection contributes to adverse outcome after brain injury. This study investigates whether autonomic nervous system activity is associated with a decreased host immune response in patients following stroke or traumatic brain injury (TBI).

METHODS

A prospective study was performed in adult patients with TBI or stroke who were admitted to the Intensive Care Unit of our tertiary university hospital between 2013 and 2016. Heart rate variability (HRV) was recorded daily and assessed for autonomic nervous system activity. Outcomes were nosocomial infections and immunosuppression, which was assessed ex vivo using whole blood stimulations with plasma of patients with infections, matched non-infected patients and healthy controls.

RESULTS

Out of 64 brain injured patients, 23 (36%) developed an infection during their hospital stay. The ability of brain injured patients to generate a host response to the bacterial endotoxin lipopolysaccharides (LPS) was diminished compared to healthy controls (p < 0.001). Patients who developed an infection yielded significantly lower TNF-α values (86 vs 192 pg/mL, p = 0.030) and a trend towards higher IL-10 values (122 vs 84 pg/mL, p = 0.071) following ex vivo whole blood stimulations when compared to patients not developing an infection. This decreased host immune response was associated with altered admission HRV values. Brain injured patients who developed an infection showed increased normalized high-frequency power compared to patients not developing an infection (0.54 vs 0.36, p = 0.033), whereas normalized low-frequency power was lower in infected patients (0.46 vs 0.64, p = 0.033).

CONCLUSION

Brain injured patients developing a nosocomial infection show parasympathetic predominance in the acute phase following brain injury, reflected by alterations in HRV, which parallels a decreased ability to generate an immune response to stimulation with LPS.