Propofol. An overview of its pharmacology and a review of its clinical efficacy in intensive care sedation

A comprehensive analysis of propofol abuse, addiction and neuropharmacological aspects: an updated review

This review aims to assess the existing studies on propofol, a relatively new intravenous anesthetic, related to its abuse and addictive potential and to explain the neurobiological and neuropharmacological aspects of propofol addiction. Several neurobiological factors related to complex processes in the brain influence propofol abuse and addiction. In this review, we assessed the literature regarding propofol abuse and addiction, including both experimental and clinical studies. We selected articles from animal studies, case reports, clinical trials, meta-analyses, narrative reviews, and systematic reviews to extract all relevant crucial quantitative data with a measure of neurobiological and neuropharmacological aspects. Thus, the main goal of this study was to investigate the current literature and discuss the association between the central nervous system and propofol abuse and addiction in the context of addictive behavior. Current data suggest that propofol has a strong addictive potential and produces prominent addiction in both animals and humans. Thus, medical practitioners should exercise caution with propofol use, and we argue that this drug should be added to the list of controlled substances.

Parameters Predictive of Propofol-Associated Acute Pancreatitis in Critically Ill Patients with COVID-19 Pneumonia: A Retrospective Cohort Study

BACKGROUND

Propofol, a commonly used agent for short- and long-term sedation, is associated with acute pancreatitis. The main indirect mechanism of propofol-associated acute pancreatitis is by inducing hypertriglyceridemia. Patients with severe coronavirus disease 2019 (COVID-19) pneumonia often require prolonged mechanical ventilation and sedation. We examined the incidence rate of acute pancreatitis among critically ill adults with COVID-19 pneumonia on mechanical ventilation receiving propofol. In addition, we attempted to determine cutoff levels of serum triglycerides and doses of propofol that are predictive of propofol-associated acute pancreatitis.

METHODS

This was a multicenter retrospective cohort study using a large dataset of hospitalized patients with COVID-19. The collected data included the number of days on propofol, cumulative doses of propofol, peak levels of serum triglycerides, serum lipase levels, and abdominal imaging findings. We used receiver-operating characteristic analysis in conjunction with Youden's index to identify the optimal thresholds for propofol administration parameters and levels of triglycerides that would provide maximal sensitivity and specificity for predicting acute pancreatitis.

RESULTS

Out of 499 critically ill patients with COVID-19 pneumonia, 154 met the inclusion criteria. Six (4%) patients had suspected acute pancreatitis based on elevated serum lipase levels. Cutoff values greater than 688 mg/dL for peak level of triglycerides, 4.5 days on propofol, 3007 mg/day for average daily propofol dose, and 24 113 mg for cumulative propofol dose were associated with high risk of suspected acute pancreatitis. The negative predictive values for suspected acute pancreatitis using these cutoffs ranged from 98% to 100%.

CONCLUSIONS

Propofol use in critically ill COVID-19 patients is associated with a low incidence rate of acute pancreatitis. We identified cutoff values for serum triglycerides and cumulative propofol dose that are linked to higher risk of propofol-associated pancreatitis. More research is needed to examine the true incidence of propofol-associated pancreatitis and help develop optimal cutoff values for certain parameters to help guide safe propofol administration.

INhaled Sedation versus Propofol in REspiratory failure in the Intensive Care Unit (INSPiRE-ICU1): protocol for a randomised, controlled trial

INTRODUCTION

Sedation in mechanically ventilated adults in the intensive care unit (ICU) is commonly achieved with intravenous infusions of propofol, dexmedetomidine or benzodiazepines. Significant limitations associated with each can impact their usage. Inhaled isoflurane has potential benefit for ICU sedation due to its safety record, sedation profile, lack of metabolism and accumulation, and fast wake-up time. Administration in the ICU has historically been restricted by the lack of a safe and effective delivery system for the ICU. The Sedaconda Anaesthetic Conserving Device-S (Sedaconda ACD-S) has enabled the delivery of inhaled volatile anaesthetics for sedation with standard ICU ventilators, but it has not yet been rigorously evaluated in the USA. We aim to evaluate the efficacy and safety of inhaled isoflurane delivered via the Sedaconda ACD-S compared with intravenous propofol for sedation of mechanically ventilated ICU adults in USA hospitals.

METHODS AND ANALYSIS

INhaled Sedation versus Propofol in REspiratory failure in the ICU (INSPiRE-ICU1) is a phase 3, multicentre, randomised, controlled, open-label, assessor-blinded trial that aims to enrol 235 critically ill adults in 14 hospitals across the USA. Eligible patients are randomised in a 1.5:1 ratio for a treatment duration of up to 48 (±6) hours or extubation, whichever occurs first, with primary follow-up period of 30 days and additional follow-up to 6 months. Primary outcome is percentage of time at target sedation range. Key secondary outcomes include use of opioids during treatment, spontaneous breathing efforts during treatment, wake-up time at end of treatment and cognitive recovery after treatment.

ETHICS AND DISSEMINATION

Trial protocol has been approved by US Food and Drug Administration (FDA) and central (Advarra SSU00208265) or local institutional review boards ((IRB), Cleveland Clinic IRB FWA 00005367, Tufts HS IRB 20221969, Houston Methodist IRB PRO00035247, Mayo Clinic IRB Mod22-001084-08, University of Chicago IRB21-1917-AM011 and Intermountain IRB 033175). Results will be presented at scientific conferences, submitted for publication, and provided to the FDA.

TRIAL REGISTRATION NUMBER

NCT05312385.

Dental treatments under sedation-analgesia in patients who are unable to collaborate: a prospective observational study

Background

Excessive fear of dental procedures leads to disruptive behavior during dental examinations and treatments. Dental examinations and treatments of these patients usually require additional techniques, such as sedation. The most commonly used techniques are inhalation of nitrous oxide, infusion of propofol with fentanyl, and premedication and infusion of midazolam.

Methods

A prospective observational epidemiological study was conducted on patients who required sedoanalgesia techniques for dental exploration and procedures. The reasons for the inability of patients to cooperate (excessive fear or intellectual disability), age, sex, weight, systemic pathology, oral pathology, treatment performed, time of intervention, anesthetic technique performed, and occurrence of complications were recorded.

Results

In total, 218 patients were studied. Sixty-five patients came for fear of dental treatment and 153 for presenting with a diagnosis of intellectual disability and not collaborating in the treatment with local anesthesia. The average age of all patients was 30.54 ± 17.30 years. The most frequent oral pathologies found in patients with excessive fear were tartar (6.8%) and wisdom teeth (6.4%), followed by missing teeth (5%). In patients with disabilities, a combination of tartar and cavities appeared most frequently (41.3%), followed by cavities (15.6%). The most frequently used sedoanalgesia technique was the infusion of propofol with fentanyl in both groups of patients, followed by nitrous oxide.

Conclusion

The combination of propofol and fentanyl was the most frequently used alternative in patients who were unable to collaborate because of intellectual disability or carry out longer or more complex treatments. Inhaled nitrous oxide and midazolam were the sedative techniques of choice for simpler oral treatments, such as tartrectomies, shallow obturations, and shorter interventions, or in younger patients.

Efficacy and safety of ciprofol versus propofol for induction and maintenance of general anesthesia: a systematic review and meta-analysis

BACKGROUND

Propofol has been the gold standard for anesthesia induction and maintenance due to its rapid onset and favorable pharmacokinetic properties. However, the search for alternative agents with improved safety and efficacy has led to the emergence of ciprofol (HSK3486), a structural analog of propofol. This systematic review and meta-analysis aim to comprehensively assess the safety and efficacy of ciprofol compared to propofol for anesthesia induction and maintenance in adult patients undergoing surgical procedures.

METHODS

This study included only double-arm RCTs in which participants were aged eighteen or older undergoing surgery. For the statistical analysis of the extracted data, we employed RevMan 5.4.1.

RESULTS

Ciprofol demonstrated a promising trend of higher anesthesiologists' satisfaction during the induction phase (MD 0.14, 95%, CI - 0.28 to 0.56, p = 0.51), whereas Propofol was favored during maintenance. Propofol also exhibited advantages with a shorter time to successful anesthesia induction (MD 0.08 min, 95% CI 0.00 to 0.15, p = 0.04), and quicker attainment of full alertness (MD 0.11 min, 95% CI - 1.29 to 1.52, p = 0.87), suggesting its efficiency in clinical practice. Importantly, there were no significant disparities in the success rate of anesthesia.

CONCLUSION

Both ciprofol and propofol demonstrate comparable efficacy and safety for anesthesia induction and maintenance in adult patients undergoing surgery. While propofol provides a faster onset of induction, ciprofol exhibits advantages in terms of pain management. Clinicians should consider these findings when selecting anesthetic agents, and tailoring choices to individual patient needs and clinical scenarios.

Remimazolam versus propofol for sedation in gastrointestinal endoscopy and colonoscopy within elderly patients: a meta-analysis of randomized controlled trials

PURPOSE

Propofol has become the sedative of choice for endoscopy and colonoscopy. However, it has shown associations with various adverse effects, specifically in the geriatric population. In contrast, remimazolam is a novel benzodiazepine, demonstrating a superior clinical safety profile. Hence, this systematic review and meta-analysis aims to clarify the efficacy and safety of remimazolam versus propofol in elderly patients (≥ 60 years) undergoing gastrointestinal endoscopic and colonoscopy procedures.

METHODS

Electronic databases including PubMed, Cochrane Library, ScienceDirect, and Google Scholar were explored from inception till January 7, 2024. The Cochrane Risk of Bias Tool for Randomized Controlled Trials (RoB-2) was utilized to evaluate the quality of each included study reported in this meta-analysis.

RESULTS

Seven randomized control trials were included, resulting in the pooling of 1,466 patients (remimazolam: 731 patients; propofol: 735 patients). Propofol demonstrated a significantly lower time to loss of consciousness (P < 0.00001, 4 studies, 784 patients) and a greater sedation success after first dose (P = 0.05, 5 studies, 1,271 patients). Remimazolam reported a significantly lower risk of bradycardia (P = 0.02, 5 studies, 1,323 patients), hypoxemia (P < 0.00001, 6 studies, 1,389 patients), and pain on injection site (P < 0.00001, 5 studies, 1,184 patients). No statistically significant differences in sedation time, number of supplemental doses, procedural parameters, and other adverse outcomes were reported.

CONCLUSION

As per the results of our analyses, propofol demonstrated comparatively superior efficacy, however, remimazolam demonstrated comparatively superior safety. The debatable evidence generated from this meta-analysis may not currently be powerful enough to advocate for the use of remimazolam in elderly patients undergoing gastrointestinal procedures; hence, further comprehensive studies are necessary in order to arrive at a robust conclusion.

Effect of Propofol on Heart Rate and Its Coupling to Cortical Slow Waves in Humans

BACKGROUND

Propofol causes significant cardiovascular depression and a slowing of neurophysiological activity. However, literature on its effect on the heart rate remains mixed, and it is not known whether cortical slow waves are related to cardiac activity in propofol anesthesia.

METHODS

The authors performed a secondary analysis of electrocardiographic and electroencephalographic data collected as part of a previously published study where n = 16 healthy volunteers underwent a slow infusion of propofol up to an estimated effect-site concentration of 4 µg/ml. Heart rate, heart rate variability, and individual slow electroencephalographic waves were extracted for each subject. Timing between slow-wave start and the preceding R-wave was tested against a uniform random surrogate. Heart rate data were further examined as a post hoc analysis in n = 96 members of an American Society of Anesthesiologists Physical Status II/III older clinical population collected as part of the AlphaMax trial.

RESULTS

The slow propofol infusion increased the heart rate in a dose-dependent manner (mean ± SD, increase of +4.2 ± 1.5 beats/min/[μg ml-1]; P < 0.001). The effect was smaller but still significant in the older clinical population. In healthy volunteers, propofol decreased the electrocardiogram R-wave amplitude (median [25th to 75th percentile], decrease of -83 [-245 to -28] μV; P < 0.001). Heart rate variability showed a loss of high-frequency parasympathetic activity. Individual cortical slow waves were coupled to the heartbeat. Heartbeat incidence peaked about 450 ms before slow-wave onset, and mean slow-wave frequency correlated with mean heart rate.

CONCLUSIONS

The authors observed a robust increase in heart rate with increasing propofol concentrations in healthy volunteers and patients. This was likely due to decreased parasympathetic cardioinhibition. Similar to non-rapid eye movement sleep, cortical slow waves are coupled to the cardiac rhythm, perhaps due to a common brainstem generator.

EDITOR’S PERSPECTIVE

Remimazolam versus propofol for procedural sedation: a meta-analysis of randomized controlled trials

Background

To improve patient tolerability and satisfaction as well as minimize complications, procedural sedation has been widely used. Propofol is the most widely used agent for induction of anesthesia and sedation by anesthesiologists. With a different mechanism compared to propofol, remimazolam is a new short-acting GABA-A receptor agonist. It is an ester-based benzodiazepine. This meta-analysis aims to clarify the efficacy and safety of remimazolam versus propofol for procedure sedation.

Methods

Electronic databases were searched for randomized controlled trials (RCTs) comparing efficacy or safety of remimazolam versus propofol. Meta-analysis were conducted using RStudio with "metafor" package with random-effects model.

Results

A total of twelve RCTs were included in the meta-analysis. The pooled results demonstrated that patients with remimazolam for procedural sedation had lower risk of bradycardia (OR 0.28, 95% CI [0.14-0.57]), hypotension (OR 0.26, 95% CI [0.22-0.32]), and respiratory depression (OR 0.22, 95% CI [0.14-0.36]). There was no difference in the risk of developing postoperative nausea and vomiting (PONV) (OR 0.65, 95% CI [0.15-2.79]) and dizziness (OR 0.93, 95% CI [0.53-1.61]) between the remimazolam and propofol groups. Using remimazolam for procedural sedation is significantly associated with less injection pain compared to propofol (OR 0.06, 95% CI [0.03-0.13]). Regarding the sedation efficacy, there was no difference in sedation success rate or time to loss of consciousness, recover and discharge between the remimazolam and the propofol groups.

Conclusions

Based on our meta-analysis, patients receiving procedural sedation with remimazolam had lower risk of bradycardia, hypotension, respiratory depression and injection pain compared with propofol. On the other hand, there was no difference in sedation success rate, risk of PONV, dizziness, time to LOC, recovery and discharge between these two sedatives.

PROSPERO registration number

CRD42022362950.

The Missing Piece? A Case for Microglia's Prominent Role in the Therapeutic Action of Anesthetics, Ketamine, and Psychedelics

There is much excitement surrounding recent research of promising, mechanistically novel psychotherapeutics - psychedelic, anesthetic, and dissociative agents - as they have demonstrated surprising efficacy in treating central nervous system (CNS) disorders, such as mood disorders and addiction. However, the mechanisms by which these drugs provide such profound psychological benefits are still to be fully elucidated. Microglia, the CNS's resident innate immune cells, are emerging as a cellular target for psychiatric disorders because of their critical role in regulating neuroplasticity and the inflammatory environment of the brain. The following paper is a review of recent literature surrounding these neuropharmacological therapies and their demonstrated or hypothesized interactions with microglia. Through investigating the mechanism of action of psychedelics, such as psilocybin and lysergic acid diethylamide, ketamine, and propofol, we demonstrate a largely under-investigated role for microglia in much of the emerging research surrounding these pharmacological agents. Among others, we detail sigma-1 receptors, serotonergic and γ-aminobutyric acid signalling, and tryptophan metabolism as pathways through which these agents modulate microglial phagocytic activity and inflammatory mediator release, inducing their therapeutic effects. The current review includes a discussion on future directions in the field of microglial pharmacology and covers bidirectional implications of microglia and these novel pharmacological agents in aging and age-related disease, glial cell heterogeneity, and state-of-the-art methodologies in microglial research.

Analgesia and sedation in critically ill pediatric patients: an update from the recent guidelines and point of view

In the last decades, the advancement of knowledge in analgesia and sedation for critically ill pediatric patients has been conspicuous and relevant. Many recommendations have changed to ensure patients' comfort during their intensive care unit (ICU) stay and prevent and treat sedation-related complications, as well as improve functional recovery and clinical outcomes. The key aspects of the analgosedation management in pediatrics have been recently reviewed in two consensus-based documents. However, there remains a lot to be researched and understood. With this narrative review and authors' point of view, we aimed to summarize the new insights presented in these two documents to facilitate their interpretation and application in clinical practice, as well as to outline research priorities in the field.    Conclusion: With this narrative review and authors' point of view, we aimed to summarize the new insights presented in these two documents to facilitate their interpretation and application in clinical practice, as well as to outline research priorities in the field. What is Known: • Critically ill pediatric patients receiving intensive care required analgesia and sedation to attenuate painful and stressful stimuli. •Optimal management of analgosedation is a challenge often burdened with complications such as tolerance, iatrogenic withdrawal syndrome, delirium, and possible adverse outcomes. What is New: •The new insights on the analgosedation treatment for critically ill pediatric patients delineated in the recent guidelines are summarized to identify strategies for changes in clinical practice. •Research gaps and potential for quality improvement projects are also highlighted.

Continuous Flow Synthesis of Propofol

Herein, we report a continuous flow process for the synthesis of 2,6-diisopropylphenol—also known as Propofol—a short-acting intravenous anesthesia, widely used in intensive care medicine to provide sedation and hypnosis. The synthesis is based on a two-step procedure: a double Friedel–Crafts alkylation followed by a decarboxylation step, both under continuous flow.

Sedation Effects Produced by a Ciprofol Initial Infusion or Bolus Dose Followed by Continuous Maintenance Infusion in Healthy Subjects: A Phase 1 Trial

Introduction

The effects of continuous infusions of ciprofol on its pharmacodynamic and pharmacokinetic properties and safety profiles in healthy Chinese subjects were evaluated.

Methods

In this open-label, randomized, two-way cross-over study, subjects received initial doses of continuous ciprofol/propofol as an infusion for 30 min in part 1 (n = 8) and a bolus dose in part 2 (n = 8) followed by maintenance infusions for a total of 4 h in part 1 and 12 h in part 2. Each subject participated in both parts with a washout time of at least 40 h.

Results

The safety and tolerability parameters of ciprofol were similar to those of propofol, and all treatment-emergent adverse events were mild. The incidences of injection pain and respiratory depression in subjects given ciprofol were lower than those receiving propofol. The pharmacokinetic parameters C_max, t_max, t_1/2, λz and MRT for ciprofol and propofol were similar, while CL, V_d and V_ss were statistically significantly different. Pharmacodynamic parameters including the Richmond Agitation Sedation Scale and bispectral index profiles of ciprofol were similar to those of propofol.

Conclusion

Ciprofol has potential for clinical application for continuous intravenous infusion to maintain sedation for 12 h with the same safety, tolerability and efficacy as propofol.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01914-4.

Propofol maintains Th17/Treg cell balance and reduces inflammation in rats with traumatic brain injury via the miR‑145‑3p/NFATc2/NF‑κB axis

Propofol is a commonly used intravenous anesthetic. The aim of the study was to examine the mechanism of propofol in traumatic brain injury (TBI) by regulating interleukin (IL)‑17 activity and maintaining the Th17/Treg balance. A rat model with moderate TBI was established using the weight‑drop method. Rats with TBI were regularly injected with propofol and their brain injuries were monitored. The peripheral blood of rats was collected to measure the Th17/Treg ratio. MicroRNA (miR)‑145‑3p expression was detected in the brain tissues of rats and antagomiR‑145‑3p was injected into the lateral ventricles of their brains to verify the effect of miR‑145‑3p on brain injury. The downstream target of miR‑145‑3p was predicted. The targeting relationship between miR‑145‑3p and nuclear factor of activated T cells c2 (NFATc2) was confirmed. NFATC2 expression and phosphorylation of NF‑κB pathway‑related proteins were measured. Propofol alleviated brain injury in rats with TBI and maintained the Th17/Treg balance. Propofol upregulated miR‑145‑3p expression in rat brains, while the inhibition of miR‑145‑3p reversed the effect of propofol on brain injury. A binding relationship was observed between miR‑145‑3p and NFATc2. Furthermore, propofol decreased the phosphorylation of p65 and IκBα, and inhibited activation of the NF‑κB pathway in the brains of rats with TBI. In conclusion, propofol maintained Th17/Treg balance and reduced inflammation in the rats with TBI via the miR‑145‑3p/NFATc2/NF‑κB axis.

Effect of combinations of morphine, dexmedetomidine and maropitant on the electroencephalogram in response to acute electrical stimulation in anaesthetized dogs

This study was conducted to compare the efficacy of combinations of morphine, dexmedetomidine and maropitant in preventing the changes in electroencephalographic (EEG) indices of nociception in anaesthetized dogs subjected to a noxious electrical stimulus. In a crossover study, eight healthy adult dogs were randomly allocated to four groups: Mor: morphine 0.6 mg/kg; Dex + Mor: morphine 0.3 mg/kg + dexmedetomidine 5 μg/kg; Maro + Mor: morphine 0.3 mg/kg + maropitant 1 mg/kg; and Dex + Maro + Mor: morphine 0.2 mg/kg + dexmedetomidine 3 μg/kg + maropitant 0.7 mg/kg. Following intramuscular administration of test drugs in a minimal anaesthesia model, a supramaximal electrical stimulus (50 V at 50 Hz for 2 s) was applied and the EEG data were recorded. There were significant increases (p < .05) in the poststimulus median frequency (F50) only in groups Mor and Maro + Mor. Dex + Mor group had a significantly lower change in F50 and F95 compared to all other treatment groups. There was no correlation of the changes in EEG frequencies with blood plasma concentration of the drugs during and after noxious stimulation. Combination of dexmedetomidine and morphine was most effective in abolishing the changes in EEG indices in response to a noxious stimulus indicating a supra-additive interaction between these two drugs.

Emergence Delirium in Perioperative Pediatric Care: A Review of Current Evidence and New Directions

Emergence delirium (ED) is defined as psychomotor agitation and delirium that typically occurs within 45 min from emergence of anesthesia. Preoperative patient conditions such as anxiety and confusion are risk factors for the development of postoperative ED. Common signs of ED are general non-purposeful resistive movements such as kicking, pulling, flailing as well as lack of eye contact and general lack of awareness of surroundings. The use of volatile anesthetics (VA) is contributory, while the use of total intravenous anesthetic techniques (TIVA) may help to reduce the incidence of emergence delirium. Furthermore, various pharmacologic strategies and alternatively non-pharmacologic strategies have been demonstrated to further diminish its occurrence. The objective of this manuscript is to provide a comprehensive review of anesthetic considerations for pediatric ED and to provide an update on techniques that have been found to be effective in reducing the overall risk of developing postoperative ED in pediatric patients.

Effects of propofol on ischemia-reperfusion and traumatic brain injury

Oxidative stress exacerbates brain damage following ischemia-reperfusion and traumatic brain injury (TBI). Management of TBI and critically ill patients commonly involves use of propofol, a sedation medication that acts as a general anesthetic with inherent antioxidant properties. Here we review available evidence from animal model systems and clinical studies that propofol protects against ischemia-reperfusion injury. However, evidence of propofol toxicity in humans exists and manifests as a rare complication, "propofol infusion syndrome" (PRIS). Evidence in animal models suggests that brain injury induces expression of the p75 neurotrophin receptor (p75NTR), which is associated with proapoptotic signaling. p75NTR-mediated apoptosis of neurons is further exacerbated by propofol's superinduction of p75NTR and concomitant inhibition of neurotrophin processing. Propofol is toxic to neurons but not astrocytes, a type of glial cell. Evidence suggests that propofol protects astrocytes from oxidative stress and stimulates astroglial-mediated protection of neurons. One may speculate that in brain injury patients under sedation/anesthesia, propofol provides brain tissue protection or aids in recovery by enhancing astrocyte function. Nevertheless, our understanding of neurologic recovery versus long-term neurological sequelae leading to neurodegeneration is poor, and it is also conceivable that propofol plays a partial as yet unrecognized role in long-term impairment of the injured brain.

A novel understanding of postoperative complications: In vitro study of the impact of propofol on epigenetic modifications in cholinergic genes

Background

Propofol is a widely used anaesthetic drug with advantageous operating conditions and recovery profile. However, propofol could have long term effects on neuronal cells and is associated with post-operative delirium (POD). In this context, one of the contributing factors to the pathogenesis of POD is a reduction of cholinesterase activity. Accordingly, we investigated the effects of propofol on the methylation, expression and activity of cholinergic genes and proteins in an in-vitro model.

Results

We found that propofol indeed reduced the activity of AChE / BChE in our in-vitro model, without affecting the protein levels. Furthermore, we could show that propofol reduced the methylation of a repressor region of the CHRNA7 gene without changing the secretion of pro–or anti-inflammatory cytokines. Lastly, propofol changed the expression patterns of genes responsible for maintaining the epigenetic status of the cell and accordingly reduced the tri-methylation of H3 K27.

Conclusion

In conclusion we found a possible functional link between propofol treatment and POD, due to a reduced cholinergic activity. In addition to this, propofol changed the expression of different maintenance genes of the epigenome that also affected histone methylation. Thus, propofol treatment may also induce strong, long lasting changes in the brain by potentially altering the epigenetic landscape.

Hypnosis for cingulate-mediated analgesia and disease treatment

Hypnosis is a technique that induces changes in perceptual experience through response to specific suggestions. By means of functional neuroimaging, a large body of clinical and experimental studies has shown that hypnotic processes modify internal (self-awareness) as well as external (environmental awareness) brain networks. Objective quantifications of this kind permit the characterization of cerebral changes after hypnotic induction and its uses in the clinical setting. Hypnosedation is one such application, as it combines hypnosis with local anesthesia in patients undergoing surgery. The power of this technique lies in the avoidance of general anesthesia and its potential complications that emerge during and after surgery. Hypnosedation is associated with improved intraoperative comfort and reduced perioperative anxiety and pain. It ensures a faster recovery of the patient and diminishes the intraoperative requirements for sedative or analgesic drugs. Mechanisms underlying the modulation of pain perception under hypnotic conditions involve cortical and subcortical areas, mainly the anterior cingulate and prefrontal cortices as well as the basal ganglia and thalami. In that respect, hypnosis-induced analgesia is an effective and highly cost-effective alternative to sedation during surgery and symptom management.

Clinical Pharmacokinetics and Pharmacodynamics of Propofol

Propofol is an intravenous hypnotic drug that is used for induction and maintenance of sedation and general anaesthesia. It exerts its effects through potentiation of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) at the GABAA receptor, and has gained widespread use due to its favourable drug effect profile. The main adverse effects are disturbances in cardiopulmonary physiology. Due to its narrow therapeutic margin, propofol should only be administered by practitioners trained and experienced in providing general anaesthesia. Many pharmacokinetic (PK) and pharmacodynamic (PD) models for propofol exist. Some are used to inform drug dosing guidelines, and some are also implemented in so-called target-controlled infusion devices, to calculate the infusion rates required for user-defined target plasma or effect-site concentrations. Most of the models were designed for use in a specific and well-defined patient category. However, models applicable in a more general population have recently been developed and published. The most recent example is the general purpose propofol model developed by Eleveld and colleagues. Retrospective predictive performance evaluations show that this model performs as well as, or even better than, PK models developed for specific populations, such as adults, children or the obese; however, prospective evaluation of the model is still required. Propofol undergoes extensive PK and PD interactions with both other hypnotic drugs and opioids. PD interactions are the most clinically significant, and, with other hypnotics, tend to be additive, whereas interactions with opioids tend to be highly synergistic. Response surface modelling provides a tool to gain understanding and explore these complex interactions. Visual displays illustrating the effect of these interactions in real time can aid clinicians in optimal drug dosing while minimizing adverse effects. In this review, we provide an overview of the PK and PD of propofol in order to refresh readers' knowledge of its clinical applications, while discussing the main avenues of research where significant recent advances have been made.

Effects of propofol anesthesia versus sevoflurane anesthesia on postoperative pain after radical gastrectomy: a randomized controlled trial

Purpose

After a radical gastrectomy, patients may experience severe pain. Some studies have reported that the use of propofol significantly reduced postoperative pain, while others have argued that this effect was not significant. Thus, we aimed to assess whether anesthesia with propofol could help to reduce pain after an open radical gastrectomy procedure.

Patients and methods

Sixty patients who were scheduled to undergo a laparotomy for radical gastrectomy were randomly assigned to either the propofol or sevoflurane group (n=30 each). A target-controlled infusion of propofol or inhalation of sevoflurane, titrated to bispectral index of 40–60, was maintained. All patients were administered a standardized multimodal analgesic plan, including intraoperative dexmedetomidine, dexamethasone, and postoperative flurbiprofen axetil, as well as patient-controlled fentanyl. Hemodynamics, pain scores, fentanyl consumption, adverse events, and the incidence of chronic pain 1 month and 3 months following hospital discharge were recorded.

Results

The intensity of postoperative pain was relatively low to moderate in all the patients. The propofol group showed lower pain scores, at rest and while coughing, up to 48 h postoperatively compared to the sevoflurane group (P<0.05). Cumulative fentanyl consumption 0–24 h after surgery was lower for the propofol group (364.4 ± 139.1 vs. 529.3 ± 237.9 µg; P=0.002). However, for fentanyl consumption 0–48 h, the difference between the two groups was not significant (710.9 ± 312.8 vs. 850.9 ± 292.0 µg; P=0.078). There were no differences in the incidences of adverse events or chronic pain between the groups.

Conclusions

Overall, the multimodal analgesic approach reduced postoperative pain after an open radical gastrectomy procedure in all patients anesthetized with either propofol or sevoflurane. Furthermore, our results indicated better analgesic outcome for the propofol group, especially in the early postoperative period.

Cardiogenic Shock: Recent Developments and Significant Knowledge Gaps

PURPOSE OF REVIEW

Patients with cardiogenic shock (CS) continue to have high rates of morbidity and mortality. We aimed to describe current principles in the management of CS including coronary revascularization, medical management, mechanical circulatory support, and supportive care.

RECENT FINDINGS

Revascularization is still recommended, but trials have not found a benefit in the revascularization of nonculprit artery lesions. New mechanical circulatory support options are available, but optimal use remains uncertain. Overall improvement in outcomes appears to have plateaued. There remain substantial knowledge gaps about the management of CS. The ideal timing and selection criteria for mechanical support remain under-developed. There has been little systematic study to inform medical management or supportive care of this patient population. A more expansive research focus is necessary to improve the care of CS.

Clonidine for sedation in the critically ill: a systematic review and meta-analysis

Background

This systematic review and meta-analysis investigates the efficacy and safety of clonidine as a sedative in critically ill patients requiring invasive mechanical ventilation.

Methods

We performed a comprehensive search of MEDLINE, EMBASE, CINAHL and the Cochrane trial registry. We identified RCTs that compared clonidine to any non-clonidine regimen in critically ill patients, excluding neonates, requiring mechanical ventilation. The GRADE method was used to assess certainty of evidence.

Results

We included eight RCTs (n = 642 patients). In seven of the trials clonidine was used for adjunctive rather than stand-alone sedation. There was no difference in the duration of mechanical ventilation (mean difference (MD) 0.05 days, 95% confidence interval (CI) = -0.65 to 0.75, I² = 86%, moderate certainty), ICU mortality (relative risk (RR) 0.98, 95% CI = 0.51 to 1.90, I² = 0%, low certainty), or ICU length of stay (MD 0.04 days, 95% CI = -0.46 to 0.53, I² = 16%, moderate certainty), with clonidine. There was a significant reduction in the total dose of narcotics (standard mean difference (SMD) -0.26, 95% CI = -0.50 to -0.02, I² = 0%, moderate certainty) with clonidine use. Clonidine was associated with increased incidence of clinically significant hypotension (RR 3.11, 95% CI = 1.64 to 5.87, I² = 0%, moderate certainty).

Conclusions

Until further RCTs are performed, data remains insufficient to support the routine use of clonidine as a sedative in the mechanically ventilated population. Clonidine may act as a narcotic-sparing agent, albeit with an increased risk of clinically significant hypotension.

Adverse Drug Reactions in the Intensive Care Unit

Adverse drug reactions (ADRs) are undesirable effects of medications used in normal doses [1]. ADRs can occur during treatment in an intensive care unit (ICU) or result in ICU admissions. A meta-analysis of 4139 studies suggests the incidence of ADRs among hospitalized patients is 17% [2]. Because of underreporting and misdiagnosis, the incidence of ADRs may be much higher and has been reported to be as high as 36% [3]. Critically ill patients are at especially high risk because of medical complexity, numerous high-alert medications, complex and often challenging drug dosing and medication regimens, and opportunity for error related to the distractions of the ICU environment [4]. Table 1 summarizes the ADRs included in this chapter.

Comparative evaluation of midazolam, dexmedetomidine, and propofol as Intensive Care Unit sedatives in postoperative electively ventilated eclamptic patients

Background and Aims:

Eclampsia is a common hypertensive disorder of pregnancy and treatment often includes termination of pregnancy with elective postoperative mechanical ventilation. The present study was aimed to compare midazolam, propofol, and dexmedetomidine for sedation and antihypertensive requirements of such patients admitted to Intensive Care Unit (ICU) after termination of pregnancy.

Material and Methods:

A total of ninety eclamptic patients administered general anesthesia for the termination of pregnancy through cesarean section and who also required postoperative ventilation were taken up for the study and were randomly allocated into three groups. All patients received MgSO4 (loading dose, 4 g intravenous) following first seizure episode followed by a continuous infusion for next 24 h. Midazolam group (GrM) received 0.05 mg/kg loading dose of midazolam, followed by infusion of 0.05–0.3 mg/kg/h, propofol group (GrP) received 1 mg/kg loading dose of propofol followed by infusion of 2–8 mg/kg/h, and dexmedetomidine group (GrD) received dexmedetomidine loading dose at 1 mcg/kg followed by infusion of 0.2–1.2 mcg/kg/h. Postoperatively, patients were assessed for hemodynamic stability, requirement of antihypertensive and analgesics, duration of sedation and stop sedation-discharge, and total time spent in the ICU.

Results:

Mean heart rate and mean arterial pressure recorded at different time intervals were lowest in GrD. Nearly 70% (n = 21) patients in the GrM required antihypertensive, 50% (n = 15) in GrP, and 36.6% (n = 11) in the GrD (P < 0.05). Duration of stop sedation-discharge from ICU was least in GrD. A number of patients demanding additional analgesics was also least in GrD.

Conclusion:

Sedation with dexmedetomidine produced better hemodynamic stability in eclamptic patients, and there was a significant reduction in requirement of additional analgesics (P = 0.035) and antihypertensive (P = 0.004). Total duration of ICU stay was also less in this group of patients.

Physicochemical compatibility and emulsion stability of propofol with commonly used analgesics and sedatives in an intensive care unit

Objectives

The purpose of this study was the determination of the physicochemical compatibility and emulsion stability of propofol with other sedatives and analgesics (clonidine hydrochloride, dexmedetomidine, 4-hydroxybutyric acid, (S)-ketamine, lormetazepam, midazolam hydrochloride, piritramide, remifentanil hydrochloride and sufentanil citrate) that are frequently administered together intravenously.

Methods

Drugs were mixed with propofol and stored without light protection at room temperature. Samples were taken at 10 points of time over 7 days. The physical stability and emulsion stability in particular were analysed by visual and microscopical inspection and by measurement of the pH value, zeta potential and globule size distribution. In addition, high-performance liquid chromatography and mass spectrometry were used to identify chemical incompatibilities.

Results

4-Hydroxybutyric acid, midazolam hydrochloride, piritramide and remifentanil hydrochloride are physically incompatible when mixed with propofol. The reason for this is the development of an increased fraction of oil droplets >5 µm leading to a higher risk of emboli. Moreover, propofol is chemically incompatible with remifentanil. The sorption of propofol to the rubber stopper of the syringe was another detectable incompatibility.

Conclusions

Propofol should not be administered with 4-hydroxybutyric acid, remifentanil hydrochloride, midazolam hydrochloride and piritramide through the same intravenous line. Based on the risk of sorption to the rubber material, propofol should be used with caution. A drug loss might occur that leads to an underdosing of the patient requiring a dose adjustment to avoid any adverse consequences. As a result of this study, the drug safety in intensive care units could be optimised.

Propofol administration improves neurological function associated with inhibition of pro-inflammatory cytokines in adult rats after traumatic brain injury

BACKGROUND

Neurological deficits following traumatic brain injury (TBI) result in dramatic impacts on the survivors, but the effect of propofol and associated mechanism are waiting to be determined.

METHODS

Adult male Sprague-Dawley rats were randomly assigned into Sham, TBI, TBI+Intralipid and TBI+Propofol group. Modified Feeney method was adopted to generate TBI model from free hammer fall injury, and animals in TBI+Propofol group were immediately treated with propofol administration for 2hours after TBI, rats after TBI without propofol treatment was used as injury control, intralipid as vehicle in propofol was injected in TBI+intralipid group. Then, neurological severity scores (NSS) were evaluated at 1, 3, 7 and 14days. Moreover, the expressions of IL-1β, IL-6 and TNF-α mRNA and protein were examined using quantitative real time-polymerase chain reaction and Western blot, immunohistochemical staining was used to localize cytokines.

RESULTS

The NSS increased greatly in the rats induced by TBI, while propofol could effectively decreased NSS, confirming the neuroprotective effect of propofol. Moreover, the mRNA expressions of IL-1β, IL-6 and TNF-α, at 1, 3, 7days after operation (dpo), were significantly augmented in the injured cortex, compared with sham one. But there was no difference between TBI and TBI+Intralipid group, but markedly decreased after propofol treatment. Additionally, the protein level of IL-1β, IL-6 and TNF-α in four groups determined by Western blot and immunohistochemistry showed the similar change with mRNA expression.

CONCLUSION

Propofol treatment could elicit a robust neuroprotective response, resulting in significant neurological function improvement for TBI rats, which was independent with intralipid. The underlying molecular mechanism may be partially associated with an inhibition of pro-inflammatory cytokines.

The relationship between sedative drug utilization and outcomes in critically ill patients undergoing mechanical ventilation

OBJECTIVES

The objectives of this study were to describe current sedative drug utilization patterns in critically ill patients undergoing mechanical ventilation (MV) in intensive care units (ICUs) in Japanese hospitals and to elucidate the relationship of these utilization patterns with patient clinical outcomes.

METHOD

Analysis of hospital claims data derived from the Quality Indicator/Improvement Project identified 12,395 critically ill adult patients who had undergone MV while hospitalized in the ICUs of 114 Japanese hospitals and had been discharged between April 2008 and March 2010. Descriptive statistics were calculated for the daily utilization of sedative drugs, opioids, and muscle relaxants in this patient sample, and the relationship between drug utilization and patient outcomes using Cox proportional hazards analysis were examined.

RESULTS

Of the 12,395 patients included in the analysis, 7300 (58.9 %), 580 (4.7 %), and 671 (5.4 %) received sedative drugs, opioids, and muscle relaxants, respectively, for ≥2 days after intubation. Compared to the other patient groups, there was a higher proportion of males in the group given sedative drugs and the patients were significantly younger (P < 0.001). Propofol was the most frequently used sedative drug, followed by benzodiazepines, barbiturates, and dexmedetomidine. The mortality rate was lower and ventilator weaning was earlier among patients who received only propofol than among those who received only benzodiazepines. Muscle relaxants were associated with increased duration of MV.

CONCLUSIONS

This is the first study based on a large-scale analysis in Japan to elucidate sedative drug utilization patterns and their relationship with outcomes in critically ill patients. The most commonly used sedative was propofol, which was associated with favorable patient outcomes. Further prospective research must be conducted to discern effective sedative drug utilization.

Bronchoscopist-directed Continuous Propofol Infusion for Targeting Moderate Sedation During Endobronchial Ultrasound Bronchoscopy: A Practical and Effective Protocol

BACKGROUND

Propofol use for sedation during routine flexible bronchoscopy is expanding. However, there are concerns over propofol's reliability in targeting moderate sedation during more complex and lengthy procedures, such as endobronchial ultrasound (EBUS) bronchoscopy. Its delivery by continuous infusion, which provides a steady sedation effect, may be a practical model for achieving reliable outcomes in this setting.

METHODS

We tested a continuous propofol infusion protocol targeting moderate sedation for EBUS bronchoscopy. A fixed loading rate of 125 mcg/kg/min and initial maintenance rate of 75 mcg/kg/min were used. Sedation assessments were performed every 2.5 minutes. The infusion was adjusted by a nurse under the direction of the bronchoscopist to maintain moderate sedation, normal vital signs, and patient comfort. Prospectively collected data from the first 31 patients using the protocol were analyzed.

RESULTS

A mix of EBUS types was performed in a fellowship training environment. Median procedure duration was 51 minutes (interquartile range, 41 to 75 min). Ninety-four percent of total bronchoscopy time was spent in moderate sedation, whereas only 1.9% was occupied by agitation-related delays. Average propofol dose per case was 0.07 mg/kg/min (±0.020), and infusion adjustments were required once every 8 minutes. Sampling goals were met in all patients, and diagnostic and nodal staging accuracies were 90% and 91%, respectively. All tumor specimens sent for genetics were sufficient for analysis. There were no major procedure-related complications.

CONCLUSION

Bronchoscopist-directed continuous propofol infusion is effective and practical for reliably and safely targeting moderate sedation during EBUS bronchoscopy, without sacrificing the breadth and accuracy of the procedure.

Conscious Intravenous Sedation in Dentistry: A Review of Current Therapy

Several sedation options are used to minimize pain, anxiety, and discomfort during oral surgery procedures. Minimizing or eliminating pain and anxiety for dental care is the primary goal for conscious sedation. Intravenous conscious sedation is a drug-induced depression of consciousness during which patients respond purposefully to verbal commands. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate as well as cardiovascular function. Patients must retain their protective airway reflexes, and respond to and understand verbal communication. The drugs and techniques used must therefore carry a broad margin of safety.

Tolerance and Withdrawal Issues with Sedatives in the Intensive Care Unit

Prolonged use of sedative medications continues to be a concern for critical care practitioners, with potential adverse effects including tolerance and withdrawal. The amount of sedatives required in critically ill patients can be lessened and tolerance delayed with the use of pain and/or sedation scales to reach the desired effect. The current recommendation for prolonged sedation is to wean patients from the medications over several days to reduce the risk of drug withdrawal. It is important to identify patients at risk for iatrogenic withdrawal and create a treatment strategy.

Clonidine for sedation in the critically ill: a systematic review and meta-analysis (protocol)

BACKGROUND

Management and choice of sedation is important during critical illness in order to reduce patient suffering and to facilitate the delivery of care. Unfortunately, medications traditionally used for sedation in the intensive care unit (ICU) such as benzodiazepines and propofol are associated with significant unwanted effects. Clonidine is an alpha-2 selective adrenergic agonist that may have a role in optimizing current sedation practices in the pediatric and adult critically ill populations by potentially minimizing exposure to other sedative agents.

METHODS/DESIGN

We will search MEDLINE, EMBASE, CINAHL, ACPJC, the Cochrane trial registry, World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), and clinicaltrials.gov for eligible observational studies and randomized controlled trials investigating the use of clonidine as an adjunctive or stand-alone sedative agent in patients requiring invasive mechanical ventilation. Our primary outcome is the duration of mechanical ventilation. Secondary outcomes include the following, listed by priority: duration of sedation infusions, dose of sedation used, level of sedation, incidence of withdrawal from other sedatives, delirium incidence, ICU and hospital length of stay, use and duration of non-invasive ventilation, and all-cause ICU and hospital mortality. We will also capture unwanted effects potentially associated with clonidine administration such as clinically significant hypotension or bradycardia, clonidine withdrawal, self-extubation, and the accidental removal of central intravenous lines and arterial lines. We will not apply any publication date, language, or journal restrictions. Two reviewers will independently screen and identify eligible studies using predefined eligibility criteria and then review full reports of all potentially relevant citations. A third reviewer will resolve disagreements if consensus cannot be achieved. We will use Review Manager (RevMan) to pool effect estimates from included studies across outcomes. We will present the results as relative risk (RR) with 95 % confidence intervals (CI) for dichotomous outcomes and as mean difference (MD) or standardized mean difference (SMD) for continuous outcomes with 95 % CI. We will assess the quality of evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

DISCUSSION

The aim of this systematic review is to summarize the evidence on the efficacy and safety of clonidine as a sedative agent in the critically ill population.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015019365.

Propofol: a review of its role in pediatric anesthesia and sedation

Propofol is an intravenous agent used commonly for the induction and maintenance of anesthesia, procedural, and critical care sedation in children. The mechanisms of action on the central nervous system involve interactions at various neurotransmitter receptors, especially the gamma-aminobutyric acid A receptor. Approved for use in the USA by the Food and Drug Administration in 1989, its use for induction of anesthesia in children less than 3 years of age still remains off-label. Despite its wide use in pediatric anesthesia, there is conflicting literature about its safety and serious adverse effects in particular subsets of children. Particularly as children are not "little adults", in this review, we emphasize the maturational aspects of propofol pharmacokinetics. Despite the myriad of propofol pharmacokinetic-pharmacodynamic studies and the ability to use allometrical scaling to smooth out differences due to size and age, there is no optimal model that can be used in target controlled infusion pumps for providing closed loop total intravenous anesthesia in children. As the commercial formulation of propofol is a nutrient-rich emulsion, the risk for bacterial contamination exists despite the Food and Drug Administration mandating addition of antimicrobial preservative, calling for manufacturers' directions to discard open vials after 6 h. While propofol has advantages over inhalation anesthesia such as less postoperative nausea and emergence delirium in children, pain on injection remains a problem even with newer formulations. Propofol is known to depress mitochondrial function by its action as an uncoupling agent in oxidative phosphorylation. This has implications for children with mitochondrial diseases and the occurrence of propofol-related infusion syndrome, a rare but seriously life-threatening complication of propofol. At the time of this review, there is no direct evidence in humans for propofol-induced neurotoxicity to the infant brain; however, current concerns of neuroapoptosis in developing brains induced by propofol persist and continue to be a focus of research.

The Effects of Nitroglycerine on Pain Control During the Propofol Injection; a Controlled, Double-Blinded, Randomized Clinical Trial

Background:

The use of Propofol often results in pain upon injection, which is sometimes very distressing for patients. Many patients report some degree of pain or discomfort on injection with propofol. Injection-induced pain during induction of anesthesia can result in patient's discomfort.

Objectives:

This study was performed to evaluate the effects of nitroglycerine on pain severity in patients undergoing propofol injection.

Patients and Methods:

In this double-blind randomized clinical trial, 100 patients with ASA class I and II undergoing anesthesia with propofol injection were selected for the study from 2012 to 2013 in Imam Reza training hospital. Patients were randomly assigned to case and control groups and received either 20 μg of nitroglycerine or normal saline as placebo. The severity of injection pain was assessed using a four-point scale. An anesthesiologist observed hemodynamic and local adverse effects.

Results:

The pain severity in nitroglycerine group was significantly lower compared with the placebo group (P < 0.0001). Moreover, the local adverse reactions were observed only in three patients in the placebo group while no patient in the drug group experienced adverse effects (P = 0.242). The systolic blood pressure showed no significant difference between two groups before and after the induction of anesthesia but the diastolic blood pressure and the heart rate was significantly different between study groups.

Conclusions:

Nitroglycerine may be a safe and effective adjuvant therapeutic for pain reduction in patients under propofol injection. Hence, its use for reduction of propofol injection-induced pain is recommended.

Locomotor stimulation by acute propofol administration in rats: Role of the nitrergic system

BACKGROUND

The addictive potential of propofol has been scientifically discussed. Drugs' psychostimulant properties that can be assessed via measurements of locomotor activity are linked to their addictive properties. No studies that have investigated the effects of propofol on locomotor activity have been reported to date. The present study sought to investigate the effects and possible mechanisms of action of propofol on locomotor activity in rats.

METHODS

Adult male albino Wistar rats (250-330g) were used as subjects. The locomotor activities of the rats were recorded for 30min immediately following intraperitoneal administration of propofol (20 and 40mg/kg), saline or vehicle (n=8 for each group). NG-nitro arginine methyl ester (l-NAME, 15-60mg/kg), a nitric oxide (NO) synthase inhibitor, and haloperidol (0.125-5mg/kg), a non-specific dopamine receptor antagonist, were also administered to other groups of rats 30min prior to the propofol (40mg/kg) injections, and locomotor activity was recorded for 30min immediately after propofol administration (n=8 for each group).

RESULTS

Propofol produced significant increases in the locomotor activities of the rats in the first 5min of the observation period [F(2,21)=9.052; p<0.001]. l-NAME [F(4,35)=3.112; p=0.02] but not haloperidol [F(4,35)=2.440; p=0.067] pretreatment blocked the propofol-induced locomotor hyperactivity. l-NAME did not cause any significant change in locomotor activity in naïve rats [F(2,21)=0.569; p=0.57].

CONCLUSIONS

Our results suggest that propofol might cause a short-term induction of locomotor activity in rats and that this effect might be related to nitrergic but not dopaminergic mechanisms.

Comparison of serum triglyceride levels with propofol in long chain triglyceride and propofol in medium and long chain triglyceride after short term anesthesia in pediatric patients

BACKGROUND

Significant increase in serum triglyceride (ST) concentration have been described in adult population after prolonged administration of propofol formulation containing long chain triglyceride (LCT). Though, medium chain triglyceride-LCT (MCT-LCT) propofol when compared with LCT propofol for long-term sedation in adults resulted in identical triglyceride levels, the elimination of triglyceride was faster in patients administered MCT-LCT propofol.

MATERIALS AND METHODS

A total of 40 children were randomized into two groups of 20 each; Group I were induced with 1% LCT propofol (3 mg/kg) and Group II with 1% medium and LCT propofol and maintained with descalating dose of 20.15 and 10 mg/kg/h at 10 min intervals. Blood samples for ST concentration were obtained before induction of anesthesia, at the end of propofol infusion and 4 h after terminating propofol infusion.

RESULTS

ST levels were raised significantly above the basal values in both the groups but the rise was significantly higher in Group I (P < 0.05). Four hours after stopping propofol infusion the triglyceride levels were similar to the basal values in Group II, whereas in Group I the values were significantly greater than the baseline (P < 0.05) as well as those of Group II (P < 0.05). No clinically significant adverse effect of hypertriglyceridemia was observed.

CONCLUSION

Even short term anesthesia with LCT and MCT-LCT propofol (1%) leads to elevated ST levels. The increase in ST levels is less with MCT-LCT propofol and elimination of triglyceride is also rapid after terminating MCT-LCT propofol infusion.

SEDASYS(®), airway, oxygenation, and ventilation: anticipating and managing the challenges

In May 2013, the FDA (Federal Drug Administration) approved SEDASYS(®), a device that enables non-anesthesia physicians to provide mild-to-moderate sedation to patients undergoing colonoscopy and esophagogastroduodenoscopy. SEDASYS(®) is the first among the devices being built to provide computer-assisted personalized sedation. Although the intention of this approval is to cut the anesthesia related expenses, it is likely to create new challenges to the users-both clinical and administrative-that might even increase the cost. Deep sedation is required frequently for a successful completion of the procedure, which poses unforeseen challenges. The present review aims to provide clear information to the users regarding pre-procedure assessment, possible sedation related complications and management options.

Cisatracurium pretreatment with tourniquet reduces propofol injection pain: a double-blind randomized controlled trial

OBJECTIVES

To investigate the efficacy of pretreatment with cisatracurium for prevention of pain associated with propofol injection, and compare its efficacy with that of lidocaine.

METHODS

Patients undergoing general anaesthesia were randomized to receive normal saline (control group), lidocaine (0.5 mg/kg), 0.03 mg/kg cisatracurium or 0.15 mg/kg cisatracurium. All drugs were administered into the largest dorsal vein of the hand with venous occlusion for 30 s, followed by propofol (0.5 mg/kg). Pain was evaluated using a four-point scale.

RESULTS

The incidence and severity of pain was significantly lower in the lidocaine and 0.15 mg/kg cisatracurium groups than the control and 0.03 mg/kg cisatracurium groups (n = 50/group). There was no significant difference between the lidocaine and 0.15 mg/kg cisatracurium groups in the incidence and severity of pain.

CONCLUSIONS

0.15 mg/kg cisatracurium effectively decreases the incidence and severity of pain induced by propofol injection without any significant complications.

Impact of deep sedation on the accuracy of hepatic and portal venous pressure measurements in patients with cirrhosis

BACKGROUND & AIMS

Measurement of the hepatic venous pressure gradient (HVPG) offers valuable prognostic information in patients with cirrhosis. In specific circumstances, (children, agitated patients, TIPS placement) deep sedation is required. This study aims to assess the impact of deep sedation on the accuracy of hepatic/portal pressure measurements.

METHODS

Forty-four patients were included. Measurements of baseline HVPG (n = 30), HVPG response to i.v. propranolol (n = 11), portal pressure gradient (PPG) after TIPS (n = 27) and of cardio-pulmonary pressures (n = 25) were obtained in awake conditions and under deep sedation with propofol and remifentanil.

RESULTS

During deep sedation, a marked oscillation within respiratory cycle was observed in abdominal pressures. End-expiratory sedated HVPG showed a better agreement with awake HVPG (intra-class correlation coefficient - ICC 0.864) than end-inspiratory HVPG (ICC 0.796). However, in almost half of the patients both values differed by more than 10%. Accuracy was not improved by using mean HVPG along the respiratory cycle. Similarly, changes in HVPG caused by propranolol while under sedation had a poor agreement to those obtained in awake conditions. Indeed, about a half of patients were misclassified according to the 10% HVPG reduction target. After TIPS, PPG values obtained under sedation were significantly different to awake PPG, usually underestimating the awake value. The systemic hemodynamic changes induced by sedation were not associated to a greater variability of PPG/HVPG measurements.

CONCLUSION

Deep sedation with propofol and remifentanil adds substantial variability and uncertainty to HVPG/PPG measurements. This must be considered when using these values to estimate prognosis, or targeting HVPG/PPG reductions.

Neurologic manifestations of acute liver failure

Fulminant hepatic failure presents with a hepatic encephalopathy and may progress to coma and often brain death from cerebral edema. This natural progression in severe cases contributes to early mortality, but outcome can be good if liver transplantation is appropriately timed and increased intracranial pressure (ICP) is managed. Neurologists and neurosurgeons have become more involved in these very challenging patients and are often asked to rapidly identify patients who are at risk of cerebral edema, to carefully select the patient population who will benefit from invasive ICP monitoring, to judge the correct time to start monitoring, to participate in treatment of cerebral edema, and to manage complications such as intracranial hemorrhage or seizures. This chapter summarizes the current multidisciplinary approach to fulminant hepatic failure and how to best bridge patients to emergency liver transplantation.

Low-Dose Remifentanil Infusion during Ventilator Weaning and Tracheal Extubation in Postoperative Intensive Care Unit Patients Sedated with Propofol-Remifentanil: A Randomised Clinical Trial

Discontinuation of sedatives for ventilator weaning and extubation can be associated with hyperdynamic responses, including hypertension and tachycardia. We examined the effects of a maintained low dose of remifentanil infusion on cardiovascular responses and coughing during extubation in postoperative intensive care unit patients sedated with propofol-remifentanil.

Fifty patients who required mechanical ventilation after major abdominal surgery were randomised into remifentanil group (n=25) or control group (n=25). Sedation during mechanical ventilation was maintained with remifentanil and propofol via a target-controlled infusion system. These drugs were titrated to the target sedation range, bispectral index values of 60 to 75 and Richmond Agitation Sedation Scale values of −3 to −2. When weaning was initiated, propofol was stopped in both groups. In the control group, remifentanil infusion was also stopped; in the remifentanil group, remifentanil infusion was maintained until extubation at a target effect site concentration of 1.0 ng/ml. Extubation was performed if the patient's respiratory, haemodynamic states were stable and if the patient was able to follow commands. Heart rate, mean arterial pressure and cough severity were evaluated.

The mean arterial pressure, heart rate and cough severity did not differ between the two groups during extubation. The time from stopping of propofol infusion to extubation was significantly longer in the remifentanil group compared to that in the control group (P=0.020).

Maintaining a low-dose remifentanil infusion during ventilator weaning delayed tracheal extubation without any differences in haemodynamic changes or coughing in postoperative intensive care unit patients.