Propofol infusion syndrome: an overview of a perplexing disease

Anesthetic Management of a Patient With Acute Necrotizing Encephalopathy Type 1

Acute necrotizing encephalopathy (ANE) is a progressive neurodegenerative condition that often arises after exposure to a variety of viruses and systemic infections, including influenza and SARS-CoV-2. It typically presents with developmental delay, seizures, dysarthria, and ataxia. Acute necrotizing encephalopathy type 1 (ANE1) is recurrent, and familial cases have been associated with mutations in the RAN-binding protein 2 (RanBP2) gene. The disease shares symptomatic and pathological resemblance with mitochondrial metabolic disorders. In this case report, we present the anesthetic management of a seven-year-old boy with ANE1 who underwent total hip reconstruction. Literature on the anesthetic management of such patients is sparse, and we discuss the patient's perioperative anesthetic management, including medications, monitoring, and care, along with a literature review.

ICU patient-on-a-chip emulating orchestration of mast cells and cerebral organoids in neuroinflammation

Propofol and midazolam are the current standard of care for prolonged sedation in Intensive Care Units (ICUs). However, the effects and mechanism of these sedatives in brain tissue are unclear. Herein, the development of an ICU patient-on-a-chip platform to elucidate those effects is reported. The humanized neural tissue compartment combines mast cells differentiated from human induced pluripotent stem cells (hiPSCs) with cerebral organoids in a three-dimensional (3D) matrix, which is covered with a membrane populated with human cerebral microvascular endothelial cells (hCMEC/D3) that separates the tissue chamber from the vascular lumen, where sedatives were infused for four days to evaluate neurotoxicity and cell-mediated immune responses. Subsequent to propofol administration, gene expressions of CD40 and TNF-α in mast cells, AIF1 in microglia and GFAP/S100B/OLIG2/MBP in macroglia were elevated, as well as NOS2, CD80, CD40, CD68, IL6 and TNF-α mediated proinflammation is noted in cerebral organoids, which resulted in higher expressions of GJB1, GABA-A and NMDAR1 in the tissue construct of the platform. Besides, midazolam administration stimulated expression of CD40 and CD203c+ reactivated mast cell proliferation and compromised BBB permeability and decreased TEER values with higher barrier disruption, whereas increased populations of CD11b+ microglia, higher expressions of GFAP/DLG4/GJB1 and GABA-A-/NMDAR1- identities, as well as glutamate related neurotoxicity and IL1B, IFNG, IFNA1, IL6 genes mediated proinflammation, resulting in increased apoptotic zones are observed in cerebral organoids. These results suggest that different sedatives cause variations in cell type activation that modulate different pathways related to neuroinflammation and neurotoxicity in the ICU patient-on-chip platform.

Case report: Successful treatment of hyperkalemia during general anesthesia in a domestic cat

Objective

This study aimed to describe the successful identification and treatment of severe hyperkalemia, cardiac arrhythmia, rhabdomyolysis, and acute kidney injury (AKI) in a domestic cat that underwent general anesthesia for abdominal exploratory surgery. The definitive underlying cause remains unknown; however, a reaction to propofol is suspected.

Case summary

A 6-month-old intact male domestic short-hair cat underwent general anesthesia and developed severe intraoperative rhabdomyolysis, hyperkalemia, ventricular fibrillation, and AKI during surgery despite a documented mild hypokalemia and normal creatinine before inducing anesthesia. Propofol was administered as part of the anesthetic protocol. The patient was resuscitated successfully and responded well to advanced medical intervention. The hyperkalemia and AKI were resolved within less than 24 h from surgery and rhabdomyolysis was resolved at the time of recheck 5 days later.

New or unique information provided

While previously suspected in dogs, to the authors' knowledge, propofol-related infusion syndrome (PRIS) has not been reported in domestic cats. Veterinary professionals should be aware that drug-induced intraoperative rhabdomyolysis and hyperkalemia can develop unexpectedly and should remain a differential for acute cardiac arrhythmias or cardiac arrest and AKI.

Neuroinflammation and status epilepticus: a narrative review unraveling a complex interplay

Status epilepticus (SE) is a medical emergency resulting from the failure of the mechanisms involved in seizure termination or from the initiation of pathways involved in abnormally prolonged seizures, potentially leading to long-term consequences, including neuronal death and impaired neuronal networks. It can eventually evolve to refractory status epilepticus (RSE), in which the administration of a benzodiazepine and another anti-seizure medications (ASMs) had been ineffective, and super-refractory status epilepticus (SRSE), which persists for more than 24 h after the administration of general anesthesia. Objective of the present review is to highlight the link between inflammation and SE. Several preclinical and clinical studies have shown that neuroinflammation can contribute to seizure onset and recurrence by increasing neuronal excitability. Notably, microglia and astrocytes can promote neuroinflammation and seizure susceptibility. In fact, inflammatory mediators released by glial cells might enhance neuronal excitation and cause drug resistance and seizure recurrence. Understanding the molecular mechanisms of neuroinflammation could be crucial for improving SE treatment, wich is currently mainly addressed with benzodiazepines and eventually phenytoin, valproic acid, or levetiracetam. IL-1β signal blockade with Anakinra has shown promising results in avoiding seizure recurrence and generalization in inflammatory refractory epilepsy. Inhibiting the IL-1β converting enzyme (ICE)/caspase-1 is also being investigated as a possible target for managing drug-resistant epilepsies. Targeting the ATP-P2X7R signal, which activates the NLRP3 inflammasome and triggers inflammatory molecule release, is another avenue of research. Interestingly, astaxanthin has shown promise in attenuating neuroinflammation in SE by inhibiting the ATP-P2X7R signal. Furthermore, IL-6 blockade using tocilizumab has been effective in RSE and in reducing seizures in patients with febrile infection-related epilepsy syndrome (FIRES). Other potential approaches include the ketogenic diet, which may modulate pro-inflammatory cytokine production, and the use of cannabidiol (CBD), which has demonstrated antiepileptic, neuroprotective, and anti-inflammatory properties, and targeting HMGB1-TLR4 axis. Clinical experience with anti-cytokine agents such as Anakinra and Tocilizumab in SE is currently limited, although promising. Nonetheless, Etanercept and Rituximab have shown efficacy only in specific etiologies of SE, such as autoimmune encephalitis. Overall, targeting inflammatory pathways and cytokines shows potential as an innovative therapeutic option for drug-resistant epilepsies and SE, providing the chance of directly addressing its underlying mechanisms, rather than solely focusing on symptom control.

Safety and efficacy of ciprofol vs propofol for sedation in intensive care unit patients with mechanical ventilation: a multi-center, open label, randomized, phase 2 trial

Background:

Ciprofol (HSK3486; Haisco Pharmaceutical Group Co., Ltd., Chengdu, China), developed as a novel 2,6-disubstituted phenol derivative showed similar tolerability and efficacy characteristics as propofol when applicated as continuous intravenous infusion for 12 h maintenance sedation in a previous phase 1 trial. The phase 2 trial was designed to investigate the safety, efficacy, and pharmacokinetic characteristics of ciprofol for sedation of patients undergoing mechanical ventilation.

Methods:

In this multicenter, open label, randomized, propofol positive-controlled, phase 2 trial, 39 Chinese intensive care unit patients receiving mechanical ventilation were enrolled and randomly assigned to a ciprofol or propofol group in a 2:1 ratio. The ciprofol infusion was started with a loading infusion of 0.1–0.2 mg/kg for 0.5–5.0 min, followed by an initial maintenance infusion rate of 0.30 mg·kg⁻¹·h⁻¹, which could be adjusted to an infusion rate of 0.06 to 0.80 mg·kg⁻¹·h⁻¹, whereas for propofol the loading infusion dose was 0.5–1.0 mg/kg for 0.5–5.0 min, followed by an initial maintenance infusion rate of 1.50 mg·kg⁻¹·h⁻¹, which could be adjusted to 0.30–4.00 mg·kg⁻¹·h⁻¹ to achieve −2 to +1 Richmond Agitation-Sedation Scale sedation within 6–24 h of drug administration.

Results:

Of the 39 enrolled patients, 36 completed the trial. The median (min, max) of the average time to sedation compliance values for ciprofol and propofol were 60.0 (52.6, 60.0) min and 60.0 (55.2, 60.0) min, with median difference of 0.00 (95% confidence interval: 0.00, 0.00). In total, 29 (74.4%) patients comprising 18 (69.2%) in the ciprofol and 11 (84.6%) in the propofol group experienced 86 treatment emergent adverse events (TEAEs), the majority being of severity grade 1 or 2. Drug- and sedation-related TEAEs were hypotension (7.7% vs. 23.1%, P = 0.310) and sinus bradycardia (3.8% vs. 7.7%, P = 1.000) in the ciprofol and propofol groups, respectively. The plasma concentration-time curves for ciprofol and propofol were similar.

Conclusions:

ciprofol is comparable to propofol with good tolerance and efficacy for sedation of Chinese intensive care unit patients undergoing mechanical ventilation in the present study setting.

Trial registration:

ClinicalTrials.gov, NCT04147416.

Principles of Pharmacotherapy of Seizures and Status Epilepticus

Status epilepticus is a neurological emergency with an outcome that is highly associated with the initial pharmacotherapy management that must be administered in a timely fashion. Beyond first-line therapy of status epilepticus, treatment is not guided by robust evidence. Optimal pharmacotherapy selection for individual patients is essential in the management of seizures and status epilepticus with careful evaluation of pharmacokinetic and pharmacodynamic factors. With the addition of newer antiseizure agents to the market, understanding their role in the management of status epilepticus is critical. Etiology-guided therapy should be considered in certain patients with drug-induced seizures, alcohol withdrawal, or autoimmune encephalitis. Some patient populations warrant special consideration, such as pediatric, pregnant, elderly, and the critically ill. Seizure prophylaxis is indicated in select patients with acute neurological injury and should be limited to the acute postinjury period.

Potentially Inappropriate Prescriptions in Heart Failure with Reduced Ejection Fraction (PIP-HFrEF)

Heart failure (HF) is a chronic debilitating and potentially life-threatening condition. Heart Failure patients are usually at high risk of polypharmacy and consequently, potentially inappropriate prescribing leading to poor clinical outcomes. Based on the published literature, a comprehensive HF-specific prescribing review tool is compiled to avoid medications that may cause HF or harm HF patients and to optimize the prescribing practice of HF guideline-directed medical therapies. Recommendations are made in line with the last versions of ESC guidelines, ESC position papers, scientific evidence, and experts' opinions.

Clinical and economic impact of the use of dexmedetomidine for sedation in the intensive care unit compared to propofol

Background Despite the advantages of dexmedetomidine (DEX) over propofol (PRO) including minimal respiratory depression and the potential for preventing and/or treating intensive care unit (ICU) delirium, PRO has been the preferred agent due to its lower cost. However, the acquisition cost of DEX has considerably decreased as a generic version of DEX has recently become available. Objective To evaluate clinical and economic outcomes of DEX-based sedation compared to PRO in the ICU. Setting A retrospective cohort study of 86 ICU patients who received either DEX or PRO for a period ≥ 12 h. Method Patients were matched by age, sex, and Sequential Organ Failure Assessment scores in a 1:1 ratio. Main outcome measure Clinical outcomes included the duration of mechanical ventilation (MV), ICU and hospital length of stay (LOS), and requirements of concomitant sedatives and opioids. Economic outcomes included the ICU and hospital costs as well as the cost of sedatives or combined sedatives and opioids per patient. Results There were no significant differences in ICU and hospital LOS and time on MV in both groups (median ICU LOS 7 [DEX] vs. 9 [PRO] days, p = 0.07; median hospital LOS 12 [DEX] vs. 14 [PRO] days, p = 0.261; median time of MV 144 [DEX] vs. 158 [PRO] hours, p = 0.176). DEX-based sedation compared to PRO was associated with similar ICU and hospital costs (US$ 67,561 vs. 78,429, p = 0.39; US$ 71,923 vs. 71,084, p = 0.1). Conclusion The clinical outcomes and economic impact associated with DEX- and PRO-based sedation were similar.

Propofol Infusion Syndrome in the Postoperative Period of a Kidney Transplant

Sedation during medical procedures poses a risk to any patient, and the use of specific anesthetic agents should be carefully considered to avoid adverse outcomes. We report on a patient with propofol infusion syndrome diagnosed during the post-operative period of a renal transplant. A 58-year-old female on chronic hemodialysis due to end stage kidney disease secondary to microscopic polyangiitis underwent kidney transplant from a deceased donor. Anesthetic induction was performed with fentanyl, propofol, and cisatracurium, and maintained with continuous propofol infusion. In the recovery room, the patient developed somnolence, tachypnea, and thoracoabdominal dissociation secondary to residual neuromuscular block. An arterial-blood gas test indicated acidemia, high pCO₂, low HCO₃, and mildly increased serum lactate. The patient remained hemodynamically stable, on volume-controlled ventilation, with sedation by continuous propofol infusion. Blood gas tests revealed persistent acidemia without tissue hypoperfusion. Doppler ultrasound of the renal graft reported adequate blood flow and serum triglycerides were elevated. A diagnosis of propofol infusion syndrome was made, and infusion ceased. A decrease in serum lactate levels was observed, with normalization 4 h later. This case highlights the importance of considering adverse effects of anesthetic agents as the cause of post-operative complications when prolonged sedation is required.

Effects of Propofol on Cellular Bioenergetics in Human Skeletal Muscle Cells

OBJECTIVES

Propofol may adversely affect the function of mitochondria and the clinical features of propofol infusion syndrome suggest that this may be linked to propofol-related bioenergetic failure. We aimed to assess the effect of therapeutic propofol concentrations on energy metabolism in human skeletal muscle cells.

DESIGN

In vitro study on human skeletal muscle cells.

SETTINGS

University research laboratories.

SUBJECTS

Patients undergoing hip surgery and healthy volunteers.

INTERVENTIONS

Vastus lateralis biopsies were processed to obtain cultured myotubes, which were exposed to a range of 1-10 μg/mL propofol for 96 hours.

MEASUREMENTS AND MAIN RESULTS

Extracellular flux analysis was used to measure global mitochondrial functional indices, glycolysis, fatty acid oxidation, and the functional capacities of individual complexes of electron transfer chain. In addition, we used [1-C]palmitate to measure fatty acid oxidation and spectrophotometry to assess activities of individual electron transfer chain complexes II-IV. Although cell survival and basal oxygen consumption rate were only affected by 10 μg/mL of propofol, concentrations as low as 1 μg/mL reduced spare electron transfer chain capacity. Uncoupling effects of propofol were mild, and not dependent on concentration. There was no inhibition of any respiratory complexes with low dose propofol, but we found a profound inhibition of fatty acid oxidation. Addition of extra fatty acids into the media counteracted the propofol effects on electron transfer chain, suggesting inhibition of fatty acid oxidation as the causative mechanism of reduced spare electron transfer chain capacity. Whether these metabolic in vitro changes are observable in other organs and at the whole-body level remains to be investigated.

CONCLUSIONS

Concentrations of propofol seen in plasma of sedated patients in ICU cause a significant inhibition of fatty acid oxidation in human skeletal muscle cells and reduce spare capacity of electron transfer chain in mitochondria.

A case report of multiple anesthesia for pediatric surgery: 80 anesthesia applications in a period of 6 years

Background

The side and adverse effects of anesthesia and its neurotoxicity to children have become major concerns of anesthesiologists in recent years.

Currently, no clinical trials have provided clear evidence indicating the suitable minimum age for a patient’s first anesthetic application, importance of anesthesia duration, number of anesthetic applications or interval between two consecutive anesthesia applications.

A very rare case concerning the side, adverse and neurotoxic effects of multiple anesthesia in a child is presented.

Case presentation

A case of a 9-year-old child who received 80 applications of anesthesia in 6 years because of corrosive esophagitis is presented. The commonly used anesthetic agents were propofol, fentanyl, rocuronium and sevoflurane.

Conclusion

In our case, there were no permanent side or adverse effects due to multiple anesthesia. The minimal psychological and scholastic problems of our case were tied to frequent hospitalization by the pediatric psychiatry consultation.

Psychotropic drug therapy in patients in the intensive care unit - usage, adverse effects, and drug interactions: a review

Managing psychological problems in patients admitted to intensive care unit (ICU) is a big challenge, requiring pharmacological interventions. On the other hand, these patients are more prone to side effects and drug interactions associated with psychotropic drugs use. Benzodiazepines (BZDs), antidepressants, and antipsychotics are commonly used in critically ill patients. Therefore, their therapeutic effects and adverse events are discussed in this study. Different studies have shown that non-BZD drugs are preferred to BZDs for agitation and pain management, but antipsychotic agents are not recommended. Also, it is better not to start antidepressants until the patient has fully recovered. However, further investigations are required for the use of psychotropic drugs in ICUs.

Clinical use of plasma lactate concentration. Part 1: Physiology, pathophysiology, and measurement

OBJECTIVE

To review the current literature with respect to the physiology, pathophysiology, and measurement of lactate.

DATA SOURCES

Data were sourced from veterinary and human clinical trials, retrospective studies, experimental studies, and review articles. Articles were retrieved without date restrictions and were sourced primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection.

HUMAN AND VETERINARY DATA SYNTHESIS

Lactate is an important energy storage molecule, the production of which preserves cellular energy production and mitigates the acidosis from ATP hydrolysis. Although the most common cause of hyperlactatemia is inadequate tissue oxygen delivery, hyperlactatemia can, and does occur in the face of apparently adequate oxygen supply. At a cellular level, the pathogenesis of hyperlactatemia varies widely depending on the underlying cause. Microcirculatory dysfunction, mitochondrial dysfunction, and epinephrine-mediated stimulation of Na⁺ -K⁺ -ATPase pumps are likely important contributors to hyperlactatemia in critically ill patients. Ultimately, hyperlactatemia is a marker of altered cellular bioenergetics.

CONCLUSION

The etiology of hyperlactatemia is complex and multifactorial. Understanding the relevant pathophysiology is helpful when characterizing hyperlactatemia in clinical patients.

Propofol Infusion Syndrome: Efficacy of a Prospective Screening Protocol

Propofol infusion syndrome (PIS) is a potentially lethal complication of propofol marked by rhabdomyolysis, metabolic acidosis, and cardiac arrhythmias or collapse. The objective of this study was to determine the effectiveness of a prospective screening protocol to prevent PIS. All trauma patients admitted who received propofol as a continuous infusion were prospectively screened from November 1, 2013 to December 31, 2015. Variables studied included demographics, injury severity, laboratory values, infusion rates, and mortality. Serum creatine phosphokinase (CPK) and lactate were drawn daily. Propofol was stopped for a positive screen defined as an increase in CPK to greater than 5000 IU/L or lactate greater than 4 mmol/L. Positive and negative cohorts were compared. Two hundred and twenty-five patients met the inclusion criteria and 12 patients (5.3%) had propofol stopped because of elevated CPK. No differences were identified in demographics, transfusions, injury severity, hospital length of stay, or propofol dose. The positive screened group had longer intensive care unit length of stay (20 vs 13 days; P = 0.002) and increased vent days (14.5 vs 10 days; P = 0.008). Max serum osmolality (334 vs 305 mosm/kg; P = 0.049) and max serum CPK (6782 vs 1058 IU/L; P < 0.0001) were higher in the positive cohort. No cases of PIS occurred, and mortality (16.7 vs 15.5%; P = 0.999) was not different between the cohorts. The screening protocol was effective in eliminating PIS. Serial CPK evaluations provided an effective screening tool and serum lactate can be dropped from screening.

Pediatric refractory and super-refractory status epilepticus

PURPOSE

To summarize the available evidence related to pediatric refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE), with emphasis on epidemiology, etiologies, therapeutic approaches, and clinical outcomes.

METHODS

Narrative review of the medical literature using MEDLINE database.

RESULTS

RSE is defined as status epilepticus (SE) that fails to respond to adequately used first- and second-line antiepileptic drugs. SRSE occurs when SE persist for 24 h or more after administration of anesthesia, or recurs after its withdrawal. RSE and SRSE represent complex neurological emergencies associated with long-term neurological dysfunction and high mortality. Challenges in management arise as the underlying etiology is not always promptly recognized and therapeutic options become limited with prolonged seizures. Treatment decisions mainly rely on case series or experts' opinions. The comparative effectiveness of different treatment strategies has not been evaluated in large prospective series or randomized clinical trials. Continuous infusion of anesthetic agents is the most common treatment for RSE and SRSE, although many questions on optimal dosing and rate of administration remain unanswered. The use of non-pharmacological therapies is documented in case series or reports with low level of evidence. In addition to neurological complications resulting from prolonged seizures, children with RSE/SRSE often develop systemic complications associated with polypharmacy and prolonged hospital stay.

CONCLUSION

RSE and SRSE are neurological emergencies with limited therapeutic options. Multi-national collaborative efforts are desirable to evaluate the safety and efficacy of current RSE/SRSE therapies, and potentially impact patients' outcomes.

Anatomical and Physiological Differences between Children and Adults Relevant to Traumatic Brain Injury and the Implications for Clinical Assessment and Care

General and central nervous system anatomy and physiology in children is different to that of adults and this is relevant to traumatic brain injury (TBI) and spinal cord injury. The controversies and uncertainties in adult neurotrauma are magnified by these differences, the lack of normative data for children, the scarcity of pediatric studies, and inappropriate generalization from adult studies. Cerebral metabolism develops rapidly in the early years, driven by cortical development, synaptogenesis, and rapid myelination, followed by equally dramatic changes in baseline and stimulated cerebral blood flow. Therefore, adult values for cerebral hemodynamics do not apply to children, and children cannot be easily approached as a homogenous group, especially given the marked changes between birth and age 8. Their cranial and spinal anatomy undergoes many changes, from the presence and disappearance of the fontanels, the presence and closure of cranial sutures, the thickness and pliability of the cranium, anatomy of the vertebra, and the maturity of the cervical ligaments and muscles. Moreover, their systemic anatomy changes over time. The head is relatively large in young children, the airway is easily compromised, the chest is poorly protected, the abdominal organs are large. Physiology changes—blood volume is small by comparison, hypothermia develops easily, intracranial pressure (ICP) is lower, and blood pressure normograms are considerably different at different ages, with potentially important implications for cerebral perfusion pressure (CPP) thresholds. Mechanisms and pathologies also differ—diffuse injuries are common in accidental injury, and growing fractures, non-accidental injury and spinal cord injury without radiographic abnormality are unique to the pediatric population. Despite these clear differences and the vulnerability of children, the amount of pediatric-specific data in TBI is surprisingly weak. There are no robust guidelines for even basics aspects of care in children, such as ICP and CPP management. This is particularly alarming given that TBI is a leading cause of death in children. To address this, there is an urgent need for pediatric-specific clinical research. If this goal is to be achieved, any clinician or researcher interested in pediatric neurotrauma must be familiar with its unique pathophysiological characteristics.

Principles of Burn Pain Management

This article describes pathophysiology of burn injury-related pain and the basic principles of burn pain management. The focus is on concepts of perioperative and periprocedural pain management with extensive discussion of opioid-based analgesia, including patient-controlled analgesia, challenges of effective opioid therapy in opioid-tolerant patients, and opioid-induced hyperalgesia. The principles of multimodal pain management are discussed, including the importance of psychological counseling, perioperative interventional pain procedures, and alternative pain management options. A brief synopsis of the principles of outpatient pain management is provided.

A Review of Agents for Palliative Sedation/Continuous Deep Sedation: Pharmacology and Practical Applications

Continuous deep sedation at the end of life is a specific form of palliative sedation requiring a care plan that essentially places and maintains the patient in an unresponsive state because their symptoms are refractory to any other interventions. Because this application is uncommon, many providers may lack practical experience in this specialized area and resources they can access are outdated, nonspecific, and/or not comprehensive. The purpose of this review is to provide an evidence- and experience-based reference that specifically addresses those medications and regimens and their practical applications for this very narrow, but vital, aspect of hospice care. Patient goals in a hospital and hospice environments are different, so the manner in which widely used sedatives are dosed and applied can differ greatly as well. Parameters applied in end-of-life care that are based on experience and a thorough understanding of the pharmacology of those medications will differ from those applied in an intensive care unit or other medical environments. By recognizing these different goals and applying well-founded regimens geared specifically for end-of-life sedation, we can address our patients' symptoms in a more timely and efficacious manner.

In vivo study of hepatic oxidative stress and mitochondrial function in rabbits with severe hypotension after propofol prolonged infusion

In humans, prolonged sedations with propofol or using high doses have been associated with propofol infusion syndrome. The main objective of this study was to evaluate the effects of prolonged high-dose administration of a specific propofol emulsion (Propofol Lipuro) and an improved lipid formulation (SMOFlipid) in liver mitochondrial bioenergetics and oxidative stress of rabbits, comparatively to a saline control. Twenty-one male New Zealand white rabbits were randomly allocated in three groups that were continuously treated for 20 h. Each group of seven animals received separately: NaCl 0.9 % (saline), SMOFlipid (lipid-based emulsion without propofol) and Lipuro 2 % (propofol lipid emulsion). An intravenous propofol bolus of 20 mg kg⁻¹ was given to the propofol Lipuro group to allow blind orotracheal intubation and mechanical ventilation. Anesthesia was maintained using infusion rates of: 20, 30, 40, 50 and 60 mg kg⁻¹ h⁻¹, according to the clinical scale of anesthetic depth and the index of consciousness values. The SMOFlipid and saline groups received the same infusion rate as the propofol Lipuro group, which were infused during 20 consecutive hours. At the end, the animals were euthanized, livers collected and mitochondria isolated by standard differential centrifugation. Mitochondrial respiration, membrane potential, swelling and oxidative stress were evaluated. Data were processed using one-way ANOVA (p < 0.05). The animals revealed a significant decrease in cardiovascular parameters showing bradycardia and severe hypotension. No statistical differences were observed when using pyruvate as substrate, however, when using succinate as respiratory substrate, significant decrease in ADP-stimulated respiration rate was observed for SMOFlipid group (p = 0.002). Lipid peroxides (p < 0.01) and protein carbonyls (p = 0.01) showed a statistically significant difference between propofol Lipuro and the SMOFlipid groups. These results suggest that lipid-based emulsions can be involved in the regulation of different pathways that ultimately lead to a decrease of state 3 mitochondrial respiration rate. The infusion of propofol Lipuro during prolonged periods, in addition to marked hypotension and hypoperfusion, also showed to have higher anti-oxidant activity and lower impairment of the mitochondrial function comparatively to the improved lipid formulation, SMOFlipid, using the rabbit as animal model.

Propofol Enhances Hemoglobin-Induced Cytotoxicity in Neurons

BACKGROUND

It has been increasingly suggested that propofol protects against hypoxic-/ischemic-induced neuronal injury. As evidenced by hemorrhage-induced stroke, hemorrhage into the brain may also cause brain damage. Whether propofol protects against hemorrhage-induced brain damage remains unknown. Therefore, in this study, we investigated the effects of propofol on hemoglobin-induced cytotoxicity in cultured mouse cortical neurons.

METHODS

Neurons were prepared from the cortex of embryonic 15-day-old mice. Hemoglobin was used to induce cytotoxicity in the neurons. The neurons were then treated with propofol for 4 hours. Cytotoxicity was determined by lactate dehydrogenase release assay. Caspase-3 activation was examined by Western blot analysis. Finally, the free radical scavenger U83836E was used to examine the potential involvement of oxidative stress in propofol's effects on hemoglobin-induced cytotoxicity.

RESULTS

We found that treatment with hemoglobin induced cytotoxicity in the neurons. Propofol enhanced hemoglobin-induced cytotoxicity. Specifically, there was a significant difference in the amount of lactate dehydrogenase release between hemoglobin plus saline (19.84% ± 5.38%) and hemoglobin plus propofol (35.79% ± 4.41%) in mouse cortical neurons (P = 0.00058, Wilcoxon Mann-Whitney U test, n = 8 in the control group or the treatment group). U83836E did not attenuate the enhancing effects of propofol on hemoglobin-induced cytotoxicity in the neurons, and propofol did not significantly affect caspase-3 activation induced by hemoglobin. These data suggested that caspase-3 activation and oxidative stress might not be the underlying mechanisms by which propofol enhanced hemoglobin-induced cytotoxicity. Moreover, these data suggested that the neuroprotective effects of propofol would be dependent on the condition of the brain injury, which will need to be confirmed in future studies.

CONCLUSIONS

These results from our current proof-of-concept study should promote more research in vitro and in vivo to develop better anesthesia care for patients with hemorrhagic stroke.

Propofol Infusion Syndrome in Refractory Status Epilepticus: A Case Report and Topical Review

Propofol infusion syndrome (PRIS) is a fatal complication when doses of propofol administration exceed 4 mg/kg/h for more than 48 hours. Propofol overdosage is not uncommon in patients with refractory status epilepticus (RSE). We describe a case of refractory status epilepticus complicated by propofol infusion syndrome and collect from 5 databases all reports of refractory status epilepticus cases that were treated by propofol and developed the syndrome and outline whether refractory status epilepticus treatment with propofol is standardized according to international recommendations, compare it with alternative medications, and discuss how this syndrome can be treated and prevented. A total of 21 patients who developed this syndrome reported arrhythmia in all cases (100%), rhabdomyolysis in 9 cases (42%), lactic acidosis in 13 cases (62%), renal failure in 8 cases (38%), lipemia in 7 cases (33%), and elevated hepatic enzymes in 6 cases (28%). 13 patients died (66%). Propofol is still given in a dosage higher than what is internationally recommended, and new treatment modalities such as renal replacement therapy, blood exchange, and extracorporeal membrane oxygenation seem to be promising. In conclusion, propofol should be carefully titrated, the maximal infusion rate needs to be reassessed, and combination of different sedative agents may be considered.

Potentially diagnostic electron paramagnetic resonance spectra elucidate the underlying mechanism of mitochondrial dysfunction in the deoxyguanosine kinase deficient rat model of a genetic mitochondrial DNA depletion syndrome

A novel rat model for a well-characterized human mitochondrial disease, mitochondrial DNA depletion syndrome with associated deoxyguanosine kinase (DGUOK) deficiency, is described. The rat model recapitulates the pathologic and biochemical signatures of the human disease. The application of electron paramagnetic (spin) resonance (EPR) spectroscopy to the identification and characterization of respiratory chain abnormalities in the mitochondria from freshly frozen tissue of the mitochondrial disease model rat is introduced. EPR is shown to be a sensitive technique for detecting mitochondrial functional abnormalities in situ and, here, is particularly useful in characterizing the redox state changes and oxidative stress that can result from depressed expression and/or diminished specific activity of the distinct respiratory chain complexes. As EPR requires no sample preparation or non-physiological reagents, it provides information on the status of the mitochondrion as it was in the functioning state. On its own, this information is of use in identifying respiratory chain dysfunction; in conjunction with other techniques, the information from EPR shows how the respiratory chain is affected at the molecular level by the dysfunction. It is proposed that EPR has a role in mechanistic pathophysiological studies of mitochondrial disease and could be used to study the impact of new treatment modalities or as an additional diagnostic tool.

Pharmacogenetics and anaesthetic drugs: Implications for perioperative practice

Pharmacogenetics seeks to elucidate the variations in individual's genetic sequences in order to better understand the differences seen in pharmacokinetics, drug metabolism, and efficacy between patients. This area of research is rapidly accelerating, aided by the use of novel and more economical molecular technologies. A substantial evidence base is being generated with the hopes that in the future it may be used to generate personalised treatment regimens in order to improve patient comfort and safety and reduce incidences of morbidity and mortality. Anaesthetics is an area of particular interest in this field, with previous research leading to better informed practice, specifically with regards to pseudocholinesterase deficiency and malignant hyperthermia. In this review, recent pharmacogenetic data pertaining to anaesthetic drugs will be presented and possible future applications and implications for practice will be discussed.

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Pharmacogenetic variations in anaesthetic drugs affect enzymes, transport proteins and drug receptors.

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Genotyping may provide more clues as to aetiology of conditions related to usage of anaesthetic drugs e.g. propofol infusion syndrome.

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Improved and more economical molecular technology will lead to increase in quantity of pharmacogenetic data.

Comparison of dexmedetomidine versus propofol for sedation in mechanically ventilated patients after cardiovascular surgery

Many cardiovascular surgeries are fast-tracked to extubation and require short-term sedation. Dexmedetomidine and propofol have very different mechanisms of action and pharmacokinetic profiles that make them attractive sedative agents in this patient population. Recently, there has been increased use of dexmedetomidine in the intensive care unit (ICU), but few studies exist or have been published directly comparing both agents in this setting. We conducted a retrospective cohort study with patients admitted to the ICU after cardiovascular surgery from January through June 2011. Adult patients who underwent coronary artery bypass and/or cardiac valve surgery received either dexmedetomidine or propofol continuous infusion for short-term sedation after cardiovascular surgery. The primary end point was time (hours) on mechanical ventilation after surgery. Secondary end points included ICU length of stay (LOS), hospital LOS, incidence of delirium, and requirement of a second sedative agent. A total of 352 patients met study inclusion criteria, with 33 enrolled in the dexmedetomidine group and 319 in the propofol group. Time on mechanical ventilation was shorter in the dexmedetomidine group (7.4 hours vs. 12.9 hours, P = .042). No difference was seen in ICU or hospital LOS. The need for a second sedative agent to achieve optimal sedation (24% vs. 27%, P = .737) and incidence of delirium (9% vs. 7.5%, P = .747) were similar between both groups. Sedation with dexmedetomidine resulted in a significant reduction in time on mechanical ventilation. However, no difference was seen in ICU or hospital LOS, incidence of delirium, or mortality.

PRIS may be diagnosed before ICU period for patients undergoing cardiopulmonary bypass

There are many published articles on the clinical manifestations of propofol-related infusion syndrome (PRIS), but they are not the same in each case.(1)Moreover, PRIS is only encountered infrequently and, therefore, it may create a diagnostic challenge. Nearly all of the published articles on PRIS are related to the use of long-term (> 48 hour) propofol infusion with a dose range of at least 4-5 mg/kg/h. In this case, not only a short duration, but also a low-dose propofol administration seems to induce PRIS. A 73-year-old male patient under cardiopulmonary bypass (CPB) suffered from some clinical symptoms of PRIS, such as hyperlactatemia and persistent low metabolic acidosis which promptly resolved on the discontinuation of propofol. Therefore, we suggest that any propofol administration (bolus or infusion) may result in such clinical symptoms, which may be the earliest indicators of PRIS. When those symptoms are observed on propofol administration during cardiopulmonary bypass (CPB), the perfusionist must alert both the anaesthesiologist and the surgeon to stop the propofol in order to prevent the patient from further adverse effects of PRIS.

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.

Intravenous hypnotic regimens in patients with liver disease; a review article

CONTEXT

The liver as an important organ in the body has many essential functions in physiological processes. One of the major activities of liver is drug metabolism. Hepatic dysfunction affecting hepatic physiological activities, especially drug metabolism can cause many problems during anesthesia and administration of different drugs to patients.

EVIDENCE ACQUISITION

Studies on hepatic disorders and hypnotic anesthetics prescribed in hepatic disorders were included in this review. For this purpose, reliable databases were used.

RESULTS

Anesthesia should be performed with caution in patients with hepatic dysfunction and drugs with long half-life should be avoided in these patients.

CONCLUSIONS

A review of the literature on the use of hypnotic drugs in patients with liver dysfunction showed that some hypnotic drugs used during anesthesia could be safely used in patients with impaired liver function. In these patients, certain drugs should be used with caution.

Use of propofol for short duration procedures in children with long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) or trifunctional protein (TFP) deficiencies

The medication propofol, commonly used for anesthesia, has been avoided in patients with mitochondrial fatty acid oxidation disorders (FAODs) due to concerns that it contains long-chain fatty acids (LCFAs), and because of reports of severe side effects in some critically ill patients receiving high-dose propofol infusions that mimic some of the symptoms regularly found in FAOD patients. In this secondary analysis, we examined the outcomes of 8 children with long-chain 3-hydroxyacyl CoA dehydrogenase (LCHAD) deficiency or trifunctional protein (TFP) deficiency who were repeatedly sedated for an electroretinogram (ERG) as part of a longitudinal study of the progression of chorioretinopathy commonly found in this population. A total of 39 sedated ERG procedures were completed using propofol for sedation. The propofol dosing, estimated total energy needs of the subject, and inpatient dietary intake recording were completed in 32 of these procedures. The LCFAs in the propofol provided approximately 1.0% of the average total daily energy needs. The sedation with propofol resulted in no adverse side effects and was safely used in this short duration procedure.

Neuromuscular complications of critical illness

Patients admitted to intensive care units (ICUs) suffer from a wide range of neurological disorders. Some develop within the ICU rendering weakness and difficulty in weaning patients from ventilator support. ICUAW, or ICU acquired weakness, is a broad term that includes several more specific neuromuscular problems. After exclusion of other causes of weakness, ICUAW includes critical illness polyneuropathy (CIP), first described by Charles Bolton, critical illness myopathy (CIM), and disorders of neuromuscular junction transmission. This chapter reviews the clinical, electrophysiological, and pathological features of these conditions and provides clinicians with approaches toward diagnosing and investigating ICUAW.

Is propofol a friend or a foe of the pediatric intensivist? Description of propofol use in a PICU*

OBJECTIVE

The primary objective is to describe the practice patterns of nonprocedural propofol use in a single-center referral PICU. The secondary objective is to describe the rate of concordance of propofol use with the PICU local practice of a maximum mean rate of 4 mg/kg/hr and a maximum duration of 24 hours and to assess for signs and symptoms of propofol infusion syndrome.

DESIGN

Retrospective descriptive cohort study.

SETTING

PICU of a tertiary care teaching hospital and referral hospital for the Western Canada.

PATIENTS

Children 1 month to 17 years old who received a nonprocedural propofol infusion between January 1, 2009, and December 31, 2009.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred twenty-three infusions (representing 210 unique patients) were included in the study. The median average infusion rate (interquartile range) including boluses was 2.7 mg/kg/hr (1.9-3.6 mg/kg/hr), and the mean infusion duration (SD) was 10.3 hours (6.7 hr). Eighty-seven percent and 98% of infusions were concordant with PICU intensivists self-reported practice maximum rate and duration, respectively. No cases of propofol-related infusion syndrome or deaths associated with propofol infusions were identified.

CONCLUSIONS

The use of propofol infusions was in concordance with PICU local practice, and propofol infusion syndrome did not developed in patients. In agreement with previous recommendations, propofol infusions in the PICU appear to be safe when limiting doses to 4 mg/kg/hr and for less than 24 hours; however, appropriate monitoring of adverse effects is still warranted due to absence of robust evidence.

Propofol infusion syndrome: a lethal condition in critically injured patients eliminated by a simple screening protocol

Propofol infusion syndrome (PIS) is defined by arrhythmia, rhabdomyolysis, lactic acidosis, and unrecognized leads to death. We sought to determine the incidence of PIS in trauma patients and evaluate the efficacy of a prospective screening protocol in this patient population.

MATERIALS AND METHODS

In Phase I of the before-and-after study (1st January, 2005-31st December, 2005), trauma patients who received propofol were evaluated. Records were reviewed for demographics, injury severity, propofol time, dose, and rates, laboratory values, and adverse events. Patients were identified with PIS based on two of the following criteria: (1) cardiac arrhythmia/collapse, (2) metabolic acidosis, (3) rhabdomyolysis, and (4) acute kidney injury. Phase II (1st January, 2006-31st December, 2011) consisted of a prospective screening protocol (elevated lactate or creatine phosphokinase (CPK)) to identify patients at risk for PIS.

RESULTS

207 patients were identified in Phase I. 6 (2.9%) developed PIS with a 50% mortality. No differences were seen in age, gender, or mechanism. PIS patients were more injured (median ISS 44 vs 26, p=0.04; median head AIS 5 vs 4, p=0.003) and received more propofol (median 50,350 vs 9770 mg, p=0.001) with longer infusion times (413 vs 65 h, p=0.001). Sodium, creatinine, and CPK levels were higher in those that developed PIS (160 vs 145 mmol/L, p=0.001; 4.3 vs 1.1mg/dL, p=0.005; 59,871 vs 520 U/L; p=0.002). Pre-screening PIS incidence was 2.9% (6/207), but after screening (January 2006) the incidence dropped to 0.19% (2/1038, p<0.001).

CONCLUSIONS

PIS is a morbid and lethal entity associated with sedation of critically injured patients. A simple screening procedure utilizing serum CPK (<5000 U/L) can essentially eliminate the development of PIS.

Anesthetic considerations in patients with mitochondrial defects

Mitochondrial disease, once thought to be a rare clinical entity, is now recognized as an important cause of a wide range of neurologic, cardiac, muscle, and endocrine disorders . The incidence of disorders of the respiratory chain alone is estimated to be about 1 per 4-5000 live births, similar to that of more well-known neurologic diseases . High-energy requiring tissues are uniquely dependent on the energy delivered by mitochondria and therefore have the lowest threshold for displaying symptoms of mitochondrial disease. Thus, mitochondrial dysfunction most commonly affects function of the central nervous system, the heart and the muscular system . Mutations in mitochondrial proteins cause striking clinical features in those tissues types, including encephalopathies, seizures, cerebellar ataxias, cardiomyopathies, myopathies, as well as gastrointestinal and hepatic disease. Our knowledge of the contribution of mitochondria in causing disease or influencing aging is expanding rapidly . As diagnosis and treatment improve for children with mitochondrial diseases, it has become increasingly common for them to undergo surgeries for their long-term care. In addition, often a muscle biopsy or other tests needing anesthesia are required for diagnosis. Mitochondrial disease represents probably hundreds of different defects, both genetic and environmental in origin, and is thus difficult to characterize. The specter of possible delayed complications in patients caused by inhibition of metabolism by anesthetics, by remaining in a biochemically stressed state such as fasting/catabolism, or by prolonged exposure to pain is a constant worry to physicians caring for these patients. Here, we review the considerations when caring for a patient with mitochondrial disease.

Propofol infusion syndrome in refractory status epilepticus

BACKGROUND AND PURPOSE

Propofol is used for treating refractory status epilepticus, which has high rate of mortality. Propofol infusion syndrome is a rare but often fatal syndrome, characterized by lactic acidosis, lipidemia, and cardiac failure, associated with propofol infusion over prolonged periods of time. We investigated the clinical factors that characterize propofol infusion syndrome to know the risk of them in refractory status epilepticus.

METHODS

This retrospective observation study was conducted in Samsung medical center from Jan. 2005 to Dec. 2009. Thirty two patients (19 males, 13 females, aged between 16 and 64 years), with refractory status epilepsy were included. Their clinical findings and treatment outcomes were evaluated retrospectively. We divided our patients into established status epilepticus (ESE) and refractory status epilepticus (RSE). And then the patients with RSE was further subdivided into propofol treatment group (RSE-P) and the other anesthetics treatment group (RSE-O). We analyzed the clinical characteristics by comparison of the groups.

RESULTS

There were significant differences of hypotension and lipid change between ESE and RSE (p<0.05). However, there was no significant difference between RSE-P and RSE-O groups. The hospital days were longer in RSE than in ESE (p=0.012) and treatment outcome was also worse in RSE than in ESE (p=0.007) but there were no significant differences of hospital stays and treatment outcome between RSE-P and RSE-O.

CONCLUSIONS

RSE is very critical disease with high mortality, which may show as many clinical changes as propofol infusion syndrome. Therefore propofol infusion syndrome might be considered as one of the clinical manifestations of RSE.

Cellular exposure to muscle relaxants and propofol could lead to genomic instability in vitro

Anesthesia is widely used in several medical settings and accepted as safe. However, there is some evidence that anesthetic agents can induce genomic changes leading to neural degeneration or apoptosis. Although chromosomal changes have not been observed in vivo, this is most likely due to DNA repair mechanisms, apoptosis, or cellular senescence. Potential chromosomal alterations after exposure to common anesthetic agents may be relevant in patients with genomic instability syndromes or with aggressive treatment of malignancies. In this study, the P388 murine B cells were cultured in vitro, and spectral karyotyping (SKY) was utilized to uncover genome-wide changes. Clinically relevant doses of cisatracurium and propofol increased structural and numerical chromosomal instability. These results may be relevant in patients with underlying chromosomal instability syndromes or concurrently being exposed to chemotherapeutic agents. Future studies may include utilization of stimulated peripheral blood lymphocytes to further confirm the significance of these results.

Anesthesia with propofol induces insulin resistance systemically in skeletal and cardiac muscles and liver of rats

Hyperglycemia together with hepatic and muscle insulin resistance are common features in critically ill patients, and these changes are associated with enhanced inflammatory response, increased susceptibility to infection, muscle wasting, and worsened prognosis. Tight blood glucose control by intensive insulin treatment may reduce the morbidity and mortality in intensive care units. Although some anesthetics have been shown to cause insulin resistance, it remains unknown how and in which tissues insulin resistance is induced by anesthetics. Moreover, the effects of propofol, a clinically relevant intravenous anesthetic, also used in the intensive care unit for sedation, on insulin sensitivity have not yet been investigated. Euglycemic hyperinsulinemic clamp study was performed in rats anesthetized with propofol and conscious unrestrained rats. To evaluate glucose uptake in tissues and hepatic glucose output [(3)H]glucose and 2-deoxy[(14)C]glucose were infused during the clamp study. Anesthesia with propofol induced a marked whole-body insulin resistance compared with conscious rats, as reflected by significantly decreased glucose infusion rate to maintain euglycemia. Insulin-stimulated tissue glucose uptake was decreased in skeletal muscle and heart, and hepatic glucose output was increased in propofol anesthetized rats. Anesthesia with propofol induces systemic insulin resistance along with decreases in insulin-stimulated glucose uptake in skeletal and heart muscle and attenuation of the insulin-mediated suppression of hepatic glucose output in rats.

Sedation for critically ill or injured adults in the intensive care unit: a shifting paradigm

As most critically ill or injured patients will require some degree of sedation, the goal of this paper was to comprehensively review the literature associated with use of sedative agents in the intensive care unit (ICU). The first and selected latter portions of this article present a narrative overview of the shifting paradigm in ICU sedation practices, indications for uninterrupted or prolonged ICU sedation, and the pharmacology of sedative agents. In the second portion, we conducted a structured, although not entirely systematic, review of the available evidence associated with use of alternative sedative agents in critically ill or injured adults. Data sources for this review were derived by searching OVID MEDLINE and PubMed from their first available date until May 2012 for relevant randomized controlled trials (RCTs), systematic reviews and/or meta-analyses and economic evaluations. Advances in the technology of mechanical ventilation have permitted clinicians to limit the use of sedation among the critically ill through daily sedative interruptions or other means. These practices have been reported to result in improved mortality, a decreased length of ICU and hospital stay and a lower risk of drug-associated delirium. However, in some cases, prolonged or uninterrupted sedation may still be indicated, such as when patients develop intracranial hypertension following traumatic brain injury. The pharmacokinetics of sedative agents have clinical importance and may be altered by critical illness or injury, co-morbid conditions and/or drug-drug interactions. Although use of validated sedation scales to monitor depth of sedation is likely to reduce adverse events, they have no utility for patients receiving neuromuscular receptor blocking agents. Depth of sedation monitoring devices such as the Bispectral Index (BIS©) also have limitations. Among existing RCTs, no sedative agent has been reported to improve the risk of mortality among the critically ill or injured. Moreover, although propofol may be associated with a shorter time to tracheal extubation and recovery from sedation than midazolam, the risk of hypertriglyceridaemia and hypotension is higher with propofol. Despite dexmedetomidine being linked with a lower risk of drug-associated delirium than alternative sedative agents, this drug increases risk of bradycardia and hypotension. Among adults with severe traumatic brain injury, there are insufficient data to suggest that any single sedative agent decreases the risk of subsequent poor neurological outcomes or mortality. The lack of examination of confounders, including the type of healthcare system in which the investigation was conducted, is a major limitation of existing pharmacoeconomic analyses, which likely limits generalizability of their results.

Nonanesthesiologist-administered propofol sedation for colonoscopy is safe and effective: a prospective Spanish study over 1000 consecutive exams

BACKGROUND AND STUDY AIMS

Propofol is increasingly being used in sedated colonoscopy. This paper assesses the safety and efficacy of nonanesthesiologist-administered propofol in a large series of colonoscopies.

PATIENTS AND METHODS

A prospective registry of consecutive American Society of Anesthetics (ASA) class I and II outpatients undergoing colonoscopy was carried out. Propofol, administered by a nurse under an endoscopist's supervision, was the sole sedative agent used.

RESULTS

Of the 1000 patients (563 women/437 men, mean age 57, range 8-89 years) included in the study, 57.4% showed ASA I and 42.6% ASA II characteristics. The cecal intubation rate was 96.9%. 48.2% of the procedures were for therapeutic purposes. The mean propofol dose was 177 mg (range 50-590 mg). Doses correlated inversely with patient age (r=-0.38; P<0.001) and were lower in ASA II patients (P<0.001) and in diagnostic (rather than therapeutic) exams (P<0.001). The average recovery time (from extracting the colonoscope to patient discharge) was 18.6 min (range 4-75) and longer in ASA II patients (P=0.05). A pulse oximetry saturation of less than 90% and a decrease in systolic blood pressure of more than 20 mmHg were observed in 24 (2.4%) and 385 (35.8%) patients, respectively. Both events were more frequent in patients older than 65 years (P<0.05); the latter was more common in ASA II patients.

CONCLUSION

Colonoscopy under endoscopist-controlled propofol sedation in low-risk patients is safe and effective, allowing for a complete exploration, although patients at least 65 years old and/or classified as ASA II are more likely to present a decrease in blood pressure and have a prolonged recovery time.

Pediatric palliative sedation therapy with propofol: recommendations based on experience in children with terminal cancer

BACKGROUND

The use of propofol for palliative sedation of children is not well documented.

OBJECTIVE

Here we describe our experience with the use of propofol palliative sedation therapy (PST) to alleviate intractable end-of-life suffering in three pediatric oncology patients, and propose an algorithm for the selection of such candidates for PST.

PATIENTS AND METHODS

We identified inpatients who had received propofol PST within 20 days of death at our institution between 2003 and 2010. Their medical records were reviewed for indicators of pain, suffering, and sedation from 48 hours before PST to the time of death. We also tabulated consumption of opioids and other symptom management medications, pain scores, and adverse events of propofol, and reviewed clinical notes for descriptors of suffering and/or palliation.

RESULTS

Three of 192 (1.6%) inpatients (aged 6-15 years) received propofol PST at the end of life. Consumption of opioids and other supportive medications decreased during PST in two cases. In the third case, pain scores remained high and sedation was the only effective comfort measure. Clinical notes suggested improved comfort and rest in all patients. Propofol infusions were continued until the time of death.

CONCLUSIONS

Our experience demonstrates that propofol PST is a useful palliative option for pediatric patients experiencing intractable suffering at the end of life. We describe an algorithm that can be used to identify such children who are candidates for PST.

Lipid metabolism disturbances and AMPK activation in prolonged propofol-sedated rabbits under mechanical ventilation

AIM

To explore the mechanisms underlying the propofol infusion syndrome (PRIS), a potentially fatal complication during prolonged propofol infusion.

METHODS

Male rabbits under mechanical ventilation through endotracheal intubation were divided into 3 groups (n=6 for each) that were sedated with 1% propofol (Group P), isoflurane (Group I) or isoflurane while receiving 10% intralipid (Group II), respectively. Blood biochemical parameters were collected at 0, 6, 12, 18, 24 and 30-36 h after the initiation of treatments. The hearts were removed out immediately after the experiments, and the level of tumor necrosis factor (TNF)-α in the hearts were studied using immunohistochemistry. AMP-activated protein kinase (AMPK) and phospho-AMPK in the hearts were assessed using Western blotting.

RESULTS

The mortality rate was 50% in Group P, and 0% in Groups I and II. The serum lipids and liver function indices in Group P were significantly increased, but moderately increased in Group II. Significant decreases in these indices were found in Groups I. All the groups showed dramatically increased release of creatine kinase (CK). Intense positive staining of TNF-α was found in all the heart samples in Group P, but only weak and neglectful staining was found in the hearts from Group II and Group I, respectively. AMPK phosphorylation was significantly increased in the hearts of Group P.

CONCLUSION

Continuous infusion of large dose of propofol in rabbits undergoing prolonged mechanical ventilation causes hyperlipidemia, liver dysfunction, increased CK levels, AMPK activation and myocardial injury. The imbalance between energy demand and utilization may contribute to PRIS.