Opioids and Mechanical Ventilation

Bayesian analysis of a systematic review of early versus late tracheostomy in ICU patients

Background

A recent systematic review and meta-analysis of RCTs of early vs late tracheostomy in mechanically ventilated patients suggest that early tracheostomy reduces the duration of ICU stay and mechanical ventilation, but does not reduce short-term mortality or ventilator-associated pneumonia (VAP). Meta-analysis of randomised trials is typically performed using a frequentist approach, and although reporting confidence intervals, interpretation is usually based on statistical significance. To provide a robust basis for clinical decision-making, we completed the search used from the previous review and analysed the data using Bayesian methods to estimate posterior probabilities of the effect of early tracheostomy on clinical outcomes.

Methods

The search was completed for RCTS comparing early vs late tracheostomy in the databases PubMed, EMBASE, and Cochrane library in June 2022. Effect estimates and 95% confidence intervals were calculated for the outcomes short-term mortality, VAP, duration of ICU stay, and mechanical ventilation. A Bayesian meta-analysis was performed with uninformative priors. Risk ratios (RRs) and standardised mean differences (SMDs) with 95% credible intervals were reported alongside posterior probabilities for any benefit (RR<1; SMD<0), a small benefit (number needed to treat, 200; SMD<–0.5), or modest benefit (number needed to treat, 100; SMD<–1).

Results

Nineteen RCTs with 3508 patients were included. Comparing patients with early vs late tracheostomy, the posterior probabilities for any benefit, small benefit, and modest benefit, respectively, were: 99%, 99%, and 99% for short-term mortality; 94%, 78%, and 51% for VAP; 97%, 43%, and 1% for duration of mechanical ventilation; and 97%, 75%, and 27% and for length of ICU stay.

Conclusions

Bayesian meta-analysis suggests a high probability that early tracheostomy compared with delayed tracheostomy has at least some benefit across all clinical outcomes considered.

Editor's Choice-The cardiovascular implications of sedatives in the cardiac intensive care unit

Patients admitted to the cardiac intensive care unit frequently develop multi-organ system dysfunction associated with their cardiac disease. In many cases, invasive mechanical ventilation is required, which often necessitates sedation for patient-ventilator synchrony, reduction of work of breathing, and patient comfort. In this paper, we describe the use of common sedatives available in the endotracheally intubated critically ill patient and emphasize the clinical and cardiovascular effects. We review γ-aminobutyric acid agonists such as etomidate, benzodiazepines, and propofol, the centrally acting α₂-agonist dexmedetomidine, and the N-methyl-D-aspartate receptor antagonist ketamine. Additionally, we outline the use of opioids and their role in potentiating other sedatives. We note that some sedatives are associated with increased delirium rates, and emphasize that judicious strategies minimizing sedative use are associated with decreases in morbidity and mortality. We also discuss standardized sedation assessment scales and highlight the importance of sedation weaning. Finally, we offer recommendations for sedation use during therapeutic hypothermia, and discuss the use of adjuvant neuromuscular blocking agents.

Optimal effect-site concentration of remifentanil for inhibiting response to laryngeal mask airway removal during emergence

PURPOSE

This randomized, controlled, double-blind study was designed to determine the optimal dose of remifentanil for preventing complications associated with the removal of a laryngeal mask airway (LMA) without delaying emergence.

MATERIALS AND METHODS

This study randomly assigned 128 patients to remifentanil effect-site concentrations (Ce) of 0 ng/mL (group R0), 0.5 ng/mL (group R0.5), 1.0 ng/mL (group R1.0), and 1.5 ng/mL (group R1.5) during emergence. The emergence and recovery profiles were recorded. Adverse events such as coughing, airway obstruction, breath-holding, agitation, desaturation, nausea, and vomiting were also evaluated.

RESULTS

The number of patients with respiratory complications such as coughing and breath-holding was significantly lower in the R1.0 and R1.5 groups than in the R0 group (p<0.05). Emergence agitation also decreased in the R1.0 and R1.5 groups (p<0.0083). The time to LMA removal was significantly longer in the R1.5 group than in the other groups (p<0.05).

CONCLUSION

Maintaining a remifentanil Ce of 1.0 ng/mL during emergence may suppress adverse events such as coughing, breath-holding, and agitation following the removal of LMA without delayed awakening.

Effect-site concentration of remifentanil to prevent cough after laryngomicrosurgery

OBJECTIVES/HYPOTHESIS

The aim of this study was to discover the optimal effect-site concentration of remifentanil for cough prevention that does not delay awakening or cause respiratory depression during emergence from anesthesia with propofol and remifentanil in laryngomicrosurgery patients.

STUDY DESIGN

Prospective, randomized, controlled trial.

METHODS

One hundred five patients were randomly assigned to maintain an effect-site concentration (Ce) of remifentanil at a predetermined value of 1 (R1), 1.5 (R1.5), and 2 (R2) ng/mL during emergence. The incidence and grade (0, no coughing; 1, single cough; 2, more than one episode of nonsustained coughing; 3, sustained and repetitive coughing with head lift) of cough, emergence time, blood pressure (MAP), heart rate (HR), spontaneous respiratory rate, oxygen saturation, and postoperative nausea and vomiting (PONV) were recorded during emergence and recovery.

RESULTS

The total number of patients with coughing during emergence was lower in groups R1.5 and R2 than in group R1. The cough grade during tracheal extubation was lower in groups R1.5 and R2 than in group R1. In group R2, emergence time was longer and postanesthesia care unit score was lower than in groups R1 and R1.5. Also in group R2, transient hypoventilation and PONV were more frequent compared to group R1. There were no differences in MAP and HR among the three groups during emergence and recovery.

CONCLUSIONS

Maintenance of remifentanil at Ce 1.5 and 2 ng/mL suppressed coughing without serious adverse events during emergence from anesthesia with propofol and remifentanil in patients undergoing laryngomicrosurgery.