Current Opinion in Critical Care最新文献

Purpose of review: This narrative review summarizes the evidence for the most commonly used intra-cardiac arrest adjunctive medications and routes of administration and discusses promising new therapies from preclinical animal models.

Recent findings: Large trials on the administration of calcium as well as the combination of vasopressin and glucocorticoids during cardiac arrest have been published. Calcium administration during cardiopulmonary resuscitation does not improve outcomes and might cause harm. Vasopressin and glucocorticoid administration during cardiopulmonary resuscitation improve the chance of return of spontaneous circulation but has uncertain effects on survival. We identified a total of seven ongoing clinical trials investigating the potential role of bicarbonate, of vasopressin and glucocorticoids, and of intravenous versus intraosseous vascular access. Several medications such as levosimendan and inhaled nitric oxide show promise in preclinical studies, and clinical trials are either planned or actively recruiting.

Summary: Large trials on intra-cardiac arrest administration of calcium and vasopressin with glucocorticoids have been performed. Several trials are ongoing that will provide valuable insights into the potential benefit of other intra-cardiac arrest medications such as bicarbonate as well as the potential benefit of intravenous or intraosseous vascular access.

Purpose of review: In the current review, we aim to highlight the evolving evidence on using diaphragm neurostimulation to develop lung and diaphragm protective mechanical ventilation.

Recent findings: Positive-pressure ventilation (PPV) causes stress and strain to the lungs which leads to ventilator-induced lung injury (VILI). In addition, PPV is frequently associated with sedatives that induce excessive diaphragm unloading which contributes to ventilator-induced diaphragmatic dysfunction (VIDD). The nonvolitional diaphragmatic contractions entrained by diaphragm neurostimulation generate negative pressure ventilation, which may be a beneficial alternative or complement to PPV. Although well established as a permanent treatment of central apnea syndromes, temporary diaphragm neurostimulation rapidly evolves to prevent and treat VILI and VIDD. Experimental and small clinical studies report comprehensive data showing that diaphragm neurostimulation has the potential to mitigate VIDD and to decrease the stress and strain applied to the lungs.

Summary: Scientific interest in temporary diaphragm neurostimulation has dramatically evolved in the last few years. Despite a solid physiological rationale and promising preliminary findings confirming a beneficial effect on the diaphragm and lungs, more studies and further technological advances will be needed to establish optimal standardized settings and lead to clinical implementation and improved outcomes.

Purpose of review: To summarize current data regarding the prevalence, risk factors, consequences, assessment and treatment of dyspnea in critically ill patients receiving invasive mechanical ventilation.

Recent findings: In intubated patients, dyspnea is frequent, perceived as intense, and associated with unfavorable outcomes such as immediate and unbearable distress (e.g. fear of dying), prolonged weaning, and delayed severe psychological consequences ( i.e. posttraumatic stress disorders). In noncommunicative patients, dyspnea is named respiratory-related brain suffering (RRBS) and can be detected using dyspnea observations scales. Before initiating pharmacological treatments, nonpharmacological interventions may be tried as they are efficient to alleviate dyspnea.

Summary: As opposed to pain, dyspnea has often been overlooked in terms of detection and management, resulting in its significant underestimation in daily practice. When it is diagnosed, dyspnea can be relieved through straightforward interventions, such as adjusting ventilator settings. Assessing dyspnea in patients undergoing invasive mechanically ventilated may be challenging, especially in noncommunicative patients (RRBS). Implementing a systematic dyspnea assessment in routine, akin to pain, could serve as a first step to reduce RRBS and prevent potential severe psychological consequences. In addition to pharmacological treatments like opioids, a promising approach is to modulate both the sensory (air on the face, trigeminal nerve stimulation) and the affective (relaxing music, hypnosis, directed empathy) components of dyspnea.

Purpose of review: To summarize basic physiological concepts of breathing effort and outline various methods for monitoring effort of inspiratory and expiratory muscles.

Recent findings: Esophageal pressure (Pes) measurement is the reference standard for respiratory muscle effort quantification, but various noninvasive screening tools have been proposed. Expiratory occlusion pressures (P0.1 and Pocc) could inform about low and high effort and the resulting lung stress, with Pocc outperforming P0.1 in identifying high effort. The pressure muscle index during an inspiratory hold could unveil inspiratory muscle effort, however obtaining a reliable inspiratory plateau can be difficult. Surface electromyography has the potential for inspiratory effort estimation, yet this is technically challenging for real-time assessment. Expiratory muscle activation is common in the critically ill warranting their assessment, that is, via gastric pressure monitoring. Expiratory muscle activation also impacts inspiratory effort interpretation which could result in both under- and overestimation of the resulting lung stress. There is likely a future role for machine learning applications to automate breathing effort monitoring at the bedside.

Summary: Different tools are available for monitoring the respiratory muscles' effort during mechanical ventilation - from noninvasive screening tools to more invasive quantification methods. This could facilitate a lung and respiratory muscle-protective ventilation approach.

Purpose of review: Mechanical ventilation may have adverse effects on diaphragm and lung function. Lung- and diaphragm-protective ventilation is an approach that challenges the clinician to facilitate physiological respiratory efforts, while maintaining minimal lung stress and strain. Here, we discuss the latest advances in monitoring and interventions to achieve lung- and diaphragm protective ventilation.

Recent findings: Noninvasive ventilator maneuvers (P0.1, airway occlusion pressure, pressure-muscle index) can accurately detect low and excessive respiratory efforts and high lung stress. Additional monitoring techniques include esophageal manometry, ultrasound, electrical activity of the diaphragm, and electrical impedance tomography. Recent trials demonstrate that a systematic approach to titrating inspiratory support and sedation facilitates lung- and diaphragm protective ventilation. Titration of positive-end expiratory pressure and, if available, veno-venous extracorporeal membrane oxygenation sweep gas flow may further modulate neural respiratory drive and effort to facilitate lung- and diaphragm protective ventilation.

Summary: Achieving lung- and diaphragm-protective ventilation may require more than a single intervention; it demands a comprehensive understanding of the (neuro)physiology of breathing and mechanical ventilation, along with the application of a series of interventions under close monitoring. We suggest a bedside-approach to achieve lung- and diaphragm protective ventilation targets.

Purposes of review: Critically ill patients frequently require mechanical ventilation and often receive sedation to control pain, reduce anxiety, and facilitate patient-ventilator interactions. Weaning from mechanical ventilation is intertwined with sedation management. In this review, we analyze the current evidence for sedation management during ventilatory weaning, including level of sedation, timing of sedation weaning, analgesic and sedative choices, and sedation management in acute respiratory distress syndrome (ARDS).

Recent findings: Despite a large body of evidence from the past 20 years regarding the importance of light sedation and paired spontaneous awakening and spontaneous breathing trials (SATs/SBTs) to promote ventilator weaning, recent studies show that implementation of these strategies lag in practice. The recent WEAN SAFE trial highlights the delay between meeting weaning criteria and first weaning attempt, with level of sedation predicting both delays and weaning failure. Recent studies show that targeted interventions around evidence-based practices for sedation weaning improve outcomes, though long-term sustainability remains a challenge.

Summary: Light or no sedation strategies that prioritize analgesia prior to sedatives along with paired SATs/SBTs promote ventilator liberation. Dexmedetomidine may have a role in weaning for agitated patients. Further investigation is needed into optimal sedation management for patients with ARDS.

Purpose of review: Recent experimental and clinical studies have suggested that spontaneous effort can potentially injure the lungs. This review summarizes the harmful effects of spontaneous breathing on the lungs during mechanical ventilation in ARDS and suggests potential strategies to minimize spontaneous breathing-induced lung injury.

Recent findings: Recent clinical and experimental studies have shown that vigorous spontaneous breathing during mechanical ventilation can potentially injure the lungs due to high transpulmonary pressure, the Pendelluft phenomenon, increased pulmonary perfusion, and patient-ventilator asynchrony. A definitive approach to minimize spontaneous breathing-induced lung injury is the systemic use of neuromuscular blocking agents; however, there is a risk of muscle atrophy. Alternatively, partial paralysis, bilateral phrenic nerve blockade, and sedatives may be useful for decreasing force generation from the diaphragm while maintaining muscle function. A higher positive end-expiratory pressure (PEEP) and prone positioning may reduce force generation from the diaphragm by decreasing neuromechanical efficiency.

Summary: Several potential strategies, including neuromuscular blockade, partial paralysis, phrenic nerve blockade, sedatives, PEEP, and prone positioning, could be useful to minimize spontaneous breathing-induced lung injury.

Purpose of review: Postextubation respiratory support treatment approaches, indications, and subgroups of patients with different responses to those therapies are rapidly changing. Planning optimal therapy in terms of choosing devices, timing of application and selecting settings with the goal of minimizing extubation failure is becoming a challenge. This review aims to analyze all the available evidence from a clinical point of view, trying to facilitate decision making at the bedside.

Recent findings: There is evidence for high flow nasal cannula support in patients at low risk of extubation failure. Noninvasive ventilation based strategies should be prioritized in patients at very high risk, who are obese or are hypercapnic at the end of a spontaneous breathing trial. Patients not included in the previous groups merit a tailored decision based on more variables.Optimizing the timing of therapy can include facilitation of extubation by transitioning to noninvasive respiratory support or prolonging a planned preventive therapy according to clinical condition.

Summary: Planning postextubatin respiratory support must consider the risk for failing and the presence of some clinical conditions favoring noninvasive ventilation.Extubation can be safely accelerated by modifying screening criteria and spontaneous breathing trial settings, but there is room to increase the role of postextubation noninvasive respiratory support for this indication, always keeping in mind the dangers of delaying a needed intubation.

Purpose of review: Guidelines recommend systematic performance of a spontaneous breathing trial (SBT) before extubation in ICUs, the objective being to reduce the risk of reintubation. In theory, a more challenging SBT performed with a T-piece may further reduce the risk of reintubation, whereas a less challenging SBT performed with pressure-support ventilation (PSV) may hasten extubation.

Recent findings: Recent findings show that a more challenging SBT with a T-piece or for a prolonged duration do not help to reduce the risk of reintubation. In contrast, a less challenging SBT with PSV is easier to pass than a T-piece, and may hasten extubation without increased risk of reintubation. Although SBT with PSV and additional positive end-expiratory pressure is indeed a less challenging SBT, further studies are needed to generalize such an easy trial in daily practice. Earlier screening for a first SBT may also decrease time to extubation without increased risk of reintubation. Lastly, reconnection to the ventilator for a short period after successful SBT facilitates recovery from the SBT-induced alveolar derecruitment.

Summary: Several recent clinical trials have improved assessment of the most adequate way to perform SBT before extubation.

Purpose of review: Past observational studies have reported the association between patient-ventilator asynchronies and poor clinical outcomes, namely longer duration of mechanical ventilation and higher mortality. But causality has remained undetermined. During the era of lung and diaphragm protective ventilation, should we revolutionize our clinical practice to detect and treat dyssynchrony?

Recent findings: Clinicians' ability to recognize asynchronies is typically low. Automatized softwares based on artificial intelligence have been trained to largely outperform human eyesight and are close to be implemented at the bedside. There is growing evidence that in susceptible patients, dyssynchrony may lead to ventilation-induced lung injury (or patient self-inflicted lung injury) and that clusters of such dyssynchronous events have the highest association with poor outcomes. Dyssynchrony may also be associated with harm indirectly when it reflects over-assistance or over-sedation. However, the occurrence of reverse triggering by means of low inspiratory efforts during passive ventilation may prevent diaphragm dysfunction and atrophy and be beneficial.

Summary: Most recent evidence on the topic suggests that synchrony between the patient and the mechanical ventilator is a critical element for protecting lung and diaphragm during the time of invasive mechanical ventilation or may reflect inadequate settings or sedation. Therefore, it is a complex situation, and clinical trials are still needed to test the effectiveness of keeping patient-ventilator interaction synchronous on clinical outcomes.