Volatile Agents in Medical and Surgical Intensive Care Units: A Meta-Analysis of Randomized Clinical Trials

Weaning-associated interventions for ventilated intensive care patients: A scoping review

BACKGROUND

Mechanical ventilation is a core intervention in critical care, but may also lead to negative consequences. Therefore, ventilator weaning is crucial for patient recovery. Numerous weaning interventions have been investigated, but an overview of interventions to evaluate different foci on weaning research is still missing.

AIM

To provide an overview of interventions associated with ventilator weaning.

STUDY DESIGN

We conducted a scoping review. A systematic search of the Medline, CINAHL and Cochrane Library databases was carried out in May 2023. Interventions from studies or reviews that aimed to extubate or decannulate mechanically ventilated patients in intensive care units were included. Studies concerning children, outpatients or non-invasive ventilation were excluded. Screening and data extraction were conducted independently by three reviewers. Identified interventions were thematically analysed and clustered.

RESULTS

Of the 7175 records identified, 193 studies were included. A total of six clusters were formed: entitled enteral nutrition (three studies), tracheostomy (17 studies), physical treatment (13 studies), ventilation modes and settings (47 studies), intervention bundles (42 studies), and pharmacological interventions including analgesic agents (8 studies), sedative agents (53 studies) and other agents (15 studies).

CONCLUSIONS

Ventilator weaning is widely researched with a special focus on ventilation modes and pharmacological agents. Some aspects remain poorly researched or unaddressed (e.g. nutrition, delirium treatment, sleep promotion).

RELEVANCE TO CLINICAL PRACTICE

This review compiles studies on ventilator weaning interventions in thematic clusters, highlighting the need for multidisciplinary care and consideration of various interventions. Future research should combine different interventions and investigate their interconnection.

Sedaconda ACD-S for Sedation with Volatile Anaesthetics in Intensive Care: A NICE Medical Technologies Guidance

Intensive care unit (ICU) patients receive highly complex care and often require sedation as part of their management. ICU sedation has traditionally been delivered using intravenous (IV) agents due to the impractical use of anaesthetic machines in this setting, which are used to deliver volatile sedation. Sedaconda anaesthetic conserving device (ACD)-S (previously known as AnaConDa-S) is a device which allows for the delivery of volatile sedation via the majority of mechanical ventilators by being inserted in the breathing circuit where the heat and moisture exchanger is normally placed. The National Institute of Health and Care Excellence (NICE), as part of the Medical Technologies Evaluation Programme, considered the potential benefits of using Sedaconda ACD-S compared to standard IV sedation in ICU patients. Here we describe the evidence evaluation undertaken by NICE on this technology, supported by CEDAR. CEDAR considered the evidence present in 21 publications that compared the clinical outcomes of patients receiving Sedaconda ACD-S-delivered sedation and IV sedation, and critiqued the economic model provided by the manufacturer. Clinical expert input during the evaluation process was used extensively to ensure that the relevant clinical evidence was captured and that the economic model was suitable for the UK setting. Due to the uncertainty of the evidence, sensitivity analysis was carried out on the key economic inputs to ensure the reliability of the results. Economic modelling has shown that Sedaconda ACD-S-delivered isoflurane sedation is cost saving on a 30-day horizon compared to IV sedation by £3833.76 per adult patient and by £2837.41 per paediatric patient. Clinical evidence indicated that Sedaconda ACD-S-delivered isoflurane sedation is associated with faster patient wake-up times than standard of care. Consequently, NICE recommended Sedaconda ACD-S as an option for delivering sedation in the ICU setting, but noted that further research should inform whether Sedaconda ACD-S-delivered sedation is of benefit to any particular subgroup of patients.

Volatile versus propofol sedation after cardiac valve surgery: a single-center prospective randomized controlled trial

BACKGROUND

Optimal intensive care of patients undergoing valve surgery is a complex balancing act between sedation for monitoring and timely postoperative awakening. It remains unclear, if these requirements can be fulfilled by volatile sedations in intensive care medicine in an efficient manner. Therefore, this study aimed to assess the time to extubation and secondary the workload required.

METHODS

We conducted a prospective randomized single-center trial at a tertiary university hospital to evaluate the postoperative management of open valve surgery patients. The study was randomized with regard to the use of volatile sedation compared to propofol sedation. Sedation was discontinued 60 min after admission for critical postoperative monitoring.

RESULTS

We observed a significantly earlier extubation (91 ± 39 min vs. 167 ± 77 min; p < 0.001), eye-opening (86 ± 28 min vs. 151 ± 71 min; p < 0.001) and command compliance (93 ± 38 min vs. 164 ± 75 min; p < 0.001) using volatile sedation, which in turn was associated with a significantly increased workload of a median of 9:56 min (± 4:16 min) set-up time. We did not observe any differences in complications. Cardiopulmonary bypass time did not differ between the groups 101 (IQR 81; 113) versus 112 (IQR 79; 136) minutes p = 0.36.

CONCLUSIONS

Using volatile sedation is associated with few minutes additional workload in assembling and enables a significantly accelerated evaluation of vulnerable patient groups. Volatile sedation has considerable advantages and emerges as a safe sedation technique in our vulnerable study population.

TRIAL REGISTRATION

Clinical trials registration (NCT04958668) was completed on 1 July 2021.

Halogenated anesthetics vs intravenous hypnotics for short and long term sedation in the intensive care unit: A meta-analysis

OBJECTIVE

To comprehensively assess peer-reviewed studies using volatile (VA) or intravenous (i/v) anesthetics for sedation in intensive care units (ICUs), with the hypothesis that the type of sedation may have an impact on survival and other clinically relevant outcomes.

DESIGN

Systematic review and meta-analysis of randomized and non-randomized trials.

SETTING

ICUs.

PARTICIPANTS

Critically ill and postoperative patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Studies comparing VA versus i/v anesthetics used in the ICU settings were independently systematically searched. Finally, 15 studies (1520 patients of predominantly surgical profile needed VA sedation for less than 96h) were included. VA had no impact on all-cause mortality (very low quality of evidence, Odds Ratio=0.82 [0.60-1.12], p=0.20). However, VA were associated with a reduction in duration of mechanical ventilation (p=0.03) and increase in ventilator-free days (p<0.001). VA also reduced postoperative levels of cardiac troponin (24h), time to extubation (p<0.001) and awakening (p=0.04).

CONCLUSIONS

In this meta-analysis, volatile sedation vs propofol caused the increase in ventilator-free days, the reduction in the duration of mechanical ventilation, time to extubation and the troponin release in medical or surgical ICU patients, while in surgical ICU patients the time to awakening was shortened.

Inhaled Sedation with Volatile Anesthetics for Mechanically Ventilated Patients in Intensive Care Units: A Narrative Review

Inhaled sedation was recently approved in Europe as an alternative to intravenous sedative drugs for intensive care unit (ICU) sedation. The aim of this narrative review was to summarize the available data from the literature published between 2005 and 2023 in terms of the efficacy, safety, and potential clinical benefits of inhaled sedation for ICU mechanically ventilated patients. The results indicated that inhaled sedation reduces the time to extubation and weaning from mechanical ventilation and reduces opioid and muscle relaxant consumption, thereby possibly enhancing recovery. Several researchers have reported its potential cardio-protective, anti-inflammatory or bronchodilator properties, alongside its minimal metabolism by the liver and kidney. The reflection devices used with inhaled sedation may increase the instrumental dead space volume and could lead to hypercapnia if the ventilator settings are not optimal and the end tidal carbon dioxide is not monitored. The risk of air pollution can be prevented by the adequate scavenging of the expired gases. Minimizing atmospheric pollution can be achieved through the judicious use of the inhalation sedation for selected groups of ICU patients, where the benefits are maximized compared to intravenous sedation. Very rarely, inhaled sedation can induce malignant hyperthermia, which prompts urgent diagnosis and treatment by the ICU staff. Overall, there is growing evidence to support the benefits of inhaled sedation as an alternative for intravenous sedation in ICU mechanically ventilated patients. The indication and management of any side effects should be clearly set and protocolized by each ICU. More randomized controlled trials (RCTs) are still required to investigate whether inhaled sedation should be prioritized over the current practice of intravenous sedation.

Inhaled Sedation for Invasively Ventilated COVID-19 Patients: A Systematic Review

Background: Volatile anesthetics were used as sedative agents in COVID-19 (Coronavirus Disease 2019) invasively ventilated patients for their potentially beneficial pharmacological effects and due to the temporary shortages of intravenous agents during the pandemic crisis. Methods: Online databases (PubMed, EMBASE, The Cochrane Central Register of Controlled Trial) and the “clinicaltrials.gov” website were searched for studies reporting the use of isoflurane, sevoflurane or desflurane. Results: We identified three manuscripts describing the beneficial effects of isoflurane on 41 COVID-19 patients with acute respiratory distress syndrome (ARDS) in Germany (n = 2) and in the USA (n = 1), in terms of reduction in the use of opioids and other sedatives. We also found a case report of two patients with transient nephrogenic diabetes insipidus, which started after 6 and 8 days of sevoflurane sedation. We identified two randomized controlled trials (RCTs; 92 patients overall), two observational studies (238 patients) on the use of volatile anesthetics in COVID-19 patients that were completed but not yet published, and one RCT interrupted for a low recruitment ratio (19 patients) and thus not published. We also identified five ongoing RCTs on the use of inhaled sedation in ARDS, which are also likely to be recruiting COVID-19 patients and which have currently enrolled a total of >1643 patients. Conclusion: Isoflurane was the most frequently used volatile agent in COVID-19 patients and allowed a reduction in the use of other sedative and analgesic drugs. Randomized evidence is building up and will be useful to confirm or challenge these findings.

Intensive care nurses' experiences using volatile anaesthetics in the intensive care unit: An exploratory study

OBJECTIVE

To explore the experiences intensive care nurses have with volatile anaesthetics in the intensive care unit.

RESEARCH METHODOLOGY AND DESIGN

A qualitative exploratory and descriptive design was used. Data were collected in 2019 from individual interviews with nine intensive care nurses, who were recruited using purposive sampling. Data were analysed using systematic text condensation.

SETTING

The study was undertaken in two general intensive care units from different university hospitals in Norway where volatile anaesthetics were utilised.

FINDINGS

Three categories emerged from the data analysis: experiencing the benefits of volatile anaesthetics; coping with unfamiliarity in handling volatile anaesthetics; and meeting challenges related to volatile anaesthetics in practice.

CONCLUSION

The intensive care nurses had positive experiences related to administering volatile anaesthetics in the intensive care unit and responded positively to the prospect of using it more often. Because volatile anaesthetics were rarely used in their units, the participants felt uncertain regarding its use due to unfamiliarity. Collegial support and guidelines were perceived as pivotal in helping them cope with this uncertainty. The participants also experienced several challenges in using volatile anaesthetics in the intensive care unit, with ambient pollution being regarded as the main challenge.

Sedating Mechanically Ventilated COVID-19 Patients with Volatile Anesthetics: Insights on the Last-Minute Potential Weapons

Coronavirus Disease 2019 (COVID-19) has spread globally with the number of cases exceeding seventy million. Although trials on potential treatments of COVID-19 Acute Respiratory Distress Syndrome (ARDS) are promising, the introduction of an effective therapeutic intervention seems elusive. In this review, we explored the potential therapeutic role of volatile anesthetics during mechanical ventilation in the late stages of the disease. COVID-19 is thought to hit the human body via five major mechanisms: direct viral damage, immune overactivation, capillary thrombosis, loss of alveolar capillary membrane integrity, and decreased tissue oxygenation. The overproduction of pro-inflammatory cytokines will eventually lead to the accumulation of inflammatory cells in the lungs, which will lead to ARDS requiring mechanical ventilation. Respiratory failure resulting from ARDS is thought to be the most common cause of death in COVID-19. The literature suggests that these effects could be directly countered by using volatile anesthetics for sedation. These agents possess multiple properties that affect viral replication, immunity, and coagulation. They also have proven benefits at the molecular, cellular, and tissue levels. Based on the comprehensive understanding of the literature, short-term sedation with volatile anesthetics may be beneficial in severe stages of COVID-19 ARDS and trials to study their effects should be encouraged.

The Use of Volatile Anesthetics as Sedatives for Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) remains to pose a high morbidity and mortality without any targeted therapies. Sedation, usually given intravenously, is an important part of clinical practice in intensive care unit (ICU), and the effect of sedatives on patients’ outcomes has been studied intensively. Although volatile anesthetics are not routine sedatives in ICU, preclinical and clinical studies suggested their potential benefit in pulmonary pathophysiology. This review will summarize the current knowledge of ARDS and the role of volatile anesthetic sedation in this setting from both clinical and mechanistic standpoints. In addition, we will review the infrastructure to use volatile anesthetics.

Efficacy and safety of inhaled anaesthetic for postoperative sedation during mechanical ventilation in adult cardiac surgery patients: a systematic review and meta-analysis

The aim was to evaluate the efficacy and safety of volatile anaesthetic for postoperative sedation in adult cardiac surgery patients through a systematic review and meta-analysis. We retrieved randomized controlled trials from MEDLINE, EMBASE, CENTRAL, Web of Science, clinical trials registries, conference proceedings, and reference lists of included articles. Independent reviewers extracted data, including patient characteristics, type of intraoperative anaesthesia, inhaled anaesthetic used, comparator sedation, and outcomes of interest, using pre-piloted forms. We assessed risk of bias using the Cochrane Tool and evaluated the strength of the evidence using the GRADE approach. Eight studies enrolling 610 patients were included. Seven had a high and one a low risk of bias. The times to extubation after intensive care unit (ICU) admission and sedation discontinuation were, respectively, 76 [95% confidence interval (CI) -150 to - 2, I2=79%] and 74 min (95% CI - 126 to - 23, I2=96%) less in patients who were sedated using volatile anaesthetic. There was no difference in ICU or hospital length of stay. Patients who received volatile anaesthetic sedation had troponin concentrations that were 0.71 ng ml-1 (95% CI 0.23-1.2) lower than control patients. Reporting on other outcomes was varied and not suitable for meta-analysis. Volatile anaesthetic sedation may be associated with a shorter time to extubation after cardiac surgery but no change in ICU or hospital length of stay. It is associated with a significantly lower postoperative troponin concentration, but the impact of this on adverse cardiovascular outcomes is uncertain. Blinded randomized trials using intention-to-treat analysis are required. PROSPERO registry number: 2016:CRD42016033874. Available from http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42016033874.

Volatile sedation in the intensive care unit: A systematic review and meta-analysis

BACKGROUND

Volatile sedation in the intensive care unit (ICU) may reduce the number of adverse events and improve patient outcomes compared with intravenous (IV) sedation. We performed a systematic review and meta-analysis comparing the effects of volatile and IV sedation in adult ICU patients.

METHODS

We searched the PubMed, Embase, Cochrane Central Register, and Web of Science databases for all randomized trials comparing volatile sedation using an anesthetic-conserving device (ACD) with IV sedation in terms of awakening and extubation times, lengths of ICU and hospital stay, and pharmacologic end-organ effects.

RESULTS

Thirteen trials with a total of 1027 patients were included. Volatile sedation (sevoflurane or isoflurane) administered through an ACD shortened the awakening time [mean difference (MD), -80.0 minutes; 95% confidence intervals (95% CIs), -134.5 to -25.6; P = .004] and extubation time (MD, -196.0 minutes; 95% CIs, -305.2 to -86.8; P < .001) compared with IV sedation (midazolam or propofol). No differences in the lengths of ICU and hospital stay were noted between the 2 groups. In the analysis of cardiac effects of sedation from 5 studies, patients who received volatile sedation showed lower serum troponin levels 6 hours after ICU admission than patients who received IV sedation (P < .05). The effect size of troponin was largest between 12 and 24 hours after ICU admission (MD, -0.27 μg/L; 95% CIs, -0.44 to -0.09; P = .003).

CONCLUSION

Compared with IV sedation, volatile sedation administered through an ACD in the ICU shortened the awakening and extubation times. Considering the difference in serum troponin levels between both arms, volatile anesthetics might have a myocardial protective effect after cardiac surgery even at a subanesthetic dose. Because the included studies used small sample sizes with high heterogeneity, further large, high-quality prospective clinical trials are needed to confirm our findings.

The New MIRUS System for Short-Term Sedation in Postsurgical ICU Patients

OBJECTIVES

To evaluate the feasibility and safety of the MIRUS system (Pall International, Sarl, Fribourg, Switzerland) for sedation with sevoflurane for postsurgical ICU patients and to evaluate atmospheric pollution during sedation.

DESIGN

Prospective interventional study.

SETTING

Surgical ICU. February 2016 to December 2016.

PATIENTS

Postsurgical patients requiring ICU admission, mechanical ventilation, and sedation.

INTERVENTIONS

Sevoflurane was administered with the MIRUS system targeted to a Richmond Agitation Sedation Scale from -3 to -5 by adaptation of minimum alveolar concentration.

MEASUREMENTS AND MAIN RESULTS

Data collected included Richmond Agitation Sedation Scale, minimum alveolar concentration, inspired and expired sevoflurane fraction, wake-up times, duration of sedation, sevoflurane consumption, respiratory and hemodynamic data, Simplified Acute Physiology Score II, Sepsis-related Organ Failure Assessment, and laboratory data and biomarkers of organ injury. Atmospheric pollution was monitored at different sites: before sevoflurane delivery (baseline) and during sedation with the probe 15 cm up to the MIRUS system (S1) and 15 cm from the filter-Reflector group (S2). Sixty-two patients were enrolled in the study. No technical failure occurred. Median Richmond Agitation Sedation Scale was -4.5 (interquartile range, -5 to -3.6) with sevoflurane delivered at a median minimum alveolar concentration of 0.45% (interquartile range, 0.4-0.53) yielding a mean inspiratory and expiratory concentrations of 0.79% (SD, 0.24) and 0.76% (SD, 0.18), respectively. Median awakening time was 4 minutes (2.2-5 min). Median duration of sevoflurane administration was 3.33 hours (2.33-5.75 hr), range 1-19 hours with a mean consumption of 7.89 mL/hr (SD, 2.99). Hemodynamics remained stable over the study period, and no laboratory data indicated liver or kidney injury or dysfunction. Median sevoflurane room air concentration was 0.10 parts per million (interquartile range, 0.07-0.15), 0.17 parts per million (interquartile range, 0.14-0.27), and 0.15 parts per million (interquartile range, 0.07-0.19) at baseline, S1, and S2, respectively.

CONCLUSIONS

The MIRUS system is a promising and safe alternative for short-term sedation with sevoflurane of ICU patients. Atmospheric pollution is largely below the recommended thresholds (< 5 parts per million). Studies extended to more heterogeneous population of patients undergoing longer duration of sedation are needed to confirm these observations.

Therapeutic hypothermia and inhalation anesthesia in a patient with severe pneumococcal meningitis and secondary cardiac arrest

Therapeutic hypothermia was associated with increased mortality in patients with severe bacterial meningitis in a large randomized trial. It still remains a treatment strategy for comatose survivors of cardiac arrest. There are several potential advantages of inhalational anesthetics as long-term sedation agents compared to intravenous sedation, however, uncontrollable increases of intracranial pressure were observed in neurocritical patients. Here we present a patient with severe bacterial meningitis and secondary cardiac arrest where therapeutic hypothermia and inhalational anesthesia were successfully used. A 59-year old female with a history of a vestibular Schwannoma surgery on the left side was admitted with signs of meningitis. Within minutes after admission, she further deteriorated with respiratory arrest, followed by cardiac arrest. She remained comatose after return of spontaneous circulation. The standard treatment of severe meningitis (steroids, antibiotics, insertion of intracranial pressure probe and external ventricular drainage) along with therapeutic hypothermia and inhalational anesthesia were implemented. Intracranial pressure remained stable and daily neurological examination was possible without being confounded by concurrent sedation. She was discharged home without neurological sequelae after 27days. In selected patients with meningitis, therapeutic hypothermia may still present a treatment option, and the long-term use of inhalational anesthetics could be appropriate with concomitant intracranial pressure monitoring.