Outcomes When Using Adjunct Dexmedetomidine with Propofol Sedation in Mechanically Ventilated Surgical Intensive Care Patients

Hemodynamic Effects of Ketamine Compared With Propofol or Dexmedetomidine as Continuous ICU Sedation

BACKGROUND

Ketamine has seen increased use for sedation in the intensive care unit. In contrast to propofol or dexmedetomidine, ketamine may provide a positive effect on hemodynamics.

OBJECTIVE

The objective of this study was to compare the development of clinically significant hypotension or bradycardia (ie, negative hemodynamic event) between critically ill adults receiving sedation with ketamine and either propofol or dexmedetomidine.

METHODS

This was a retrospective cohort study of adults admitted to an intensive care unit at an academic medical center between January 2016 and January 2021.

RESULTS

Patients in the ketamine group (n = 78) had significantly less clinically significant hypotension or bradycardia compared with those receiving propofol or dexmedetomidine (n = 156) (34.6% vs 63.5%; P < 0.001). Patients receiving ketamine also experienced smaller degree of hypotension observed by percent decrease in mean arterial pressure (25.3% [17.4] vs 33.8% [14.5]; P < 0.001) and absolute reduction in systolic blood pressure (26.5 [23.8] vs 42.0 [37.8] mm Hg; P < 0.001) and bradycardia (15.5 [24.3] vs 32.0 [23.0] reduction in beats per minute; P < 0.001). In multivariate logistic regression modeling, receipt of propofol or dexmedetomidine was the only independent predictor of a negative hemodynamic event (odds ratio [OR]: 3.3, 95% confidence interval [CI], 1.7 to 6.1; P < 0.001).

CONCLUSION AND RELEVANCE

Ketamine was associated with less clinically relevant hypotension or bradycardia when compared with propofol or dexmedetomidine, in addition to a smaller absolute decrease in hemodynamic parameters. The clinical significance of these findings requires further investigation.

A "Smart" Biosensor-Enabled Intravascular Catheter and Platform for Dynamic Delivery of Propofol to "Close the Loop" for Total Intravenous Anesthesia

BACKGROUND

Target-controlled infusion anesthesia is used worldwide to provide user-defined, stable, blood concentrations of propofol for sedation and anesthesia. The drug infusion is controlled by a microprocessor that uses population-based pharmacokinetic data and patient biometrics to estimate the required infusion rate to replace losses from the blood compartment due to drug distribution and metabolism. The objective of the research was to develop and validate a method to detect and quantify propofol levels in the blood, to improve the safety of propofol use, and to demonstrate a pathway for regulatory approval for its use in the USA.

METHODS

We conceptualized and prototyped a novel "smart" biosensor-enabled intravenous catheter capable of quantifying propofol at physiologic levels in the blood, in real time. The clinical embodiment of the platform is comprised of a "smart" biosensor-enabled catheter prototype, a signal generation/detection readout display, and a driving electronics software. The biosensor was validated in vitro using a variety of electrochemical methods in both static and flow systems with biofluids, including blood.

RESULTS

We present data demonstrating the experimental detection and quantification of propofol at sub-micromolar concentrations using this biosensor and method. Detection of the drug is rapid and stable with negligible biofouling due to the sensor coating. It shows a linear correlation with mass spectroscopy methods. An intuitive graphical user interface was developed to: (1) detect and quantify the propofol sensor signal, (2) determine the difference between targeted and actual propofol concentration, (3) communicate the variance in real time, and (4) use the output of the controller to drive drug delivery from an in-line syringe pump. The automated delivery and maintenance of propofol levels was demonstrated in a modeled benchtop "patient" applying the known pharmacokinetics of the drug using published algorithms.

CONCLUSIONS

We present a proof-of-concept and in vitro validation of accurate electrochemical quantification of propofol directly from the blood and the design and prototyping of a "smart," indwelling, biosensor-enabled catheter and demonstrate feedback hardware and software architecture permitting accurate measurement of propofol in blood in real time. The controller platform is shown to permit autonomous, "closed-loop" delivery of the drug and maintenance of user-defined propofol levels in a dynamic flow model.

A New ICU Delirium Prevention Bundle to Reduce the Incidence of Delirium: A Randomized Parallel Group Trial

Introduction

Although various preventive strategies have been advocated, delirium is common in critically ill patients and is associated with increased morbidity, mortality, and long-term adverse effects. The efficacy of a novel delirium prevention bundle in mechanically ventilated critically ill patients was investigated in this study.

Methods

In this randomized controlled trial, 50 mechanically ventilated adult patients in a tertiary care medical-surgical intensive care unit (ICU) were randomized to receive either delirium prevention bundle protocol or standard of care protocol. Delirium was assessed daily using the Confusion Assessment Method for the ICU (CAM-ICU) score by an independent investigator up to 28 days or death or discharge. The primary outcome was the incidence of new-onset delirium. Secondary outcomes were duration of mechanical ventilation, ICU length of stay (ICU-LOS), hospital LOS, and other adverse events.

Results

There was a 20% reduction in the incidence of delirium in the intervention group (36 vs 56%; p = 0.156). The 28-day mortality (28 vs 24%; p = 0.747), duration of mechanical ventilation (9 vs 12 days; p = 0.281), ICU-LOS (11 vs 12 days; p = 0.221), and hospital LOS (16 vs 20 days; p = 0.062) were similar between the groups.

Conclusion

Implementation of delirium prevention bundle does not reduce the incidence of delirium compared to standard of care protocol in mechanically ventilated critically ill patients.

How to cite this article

Malik AK, Baidya DK, Anand RK, Subramaniam R. A New ICU Delirium Prevention Bundle to Reduce the Incidence of Delirium: A Randomized Parallel Group Trial. Indian J Crit Care Med 2021;25(7):754–760.