Use of propofol and other nonbenzodiazepine sedatives in the intensive care unit

Effects of adding low-dose esketamine to sufentanil and propofol sedation during cervical conization: a single-centre, randomized controlled trial

BACKGROUND

Cervical conization is a brief but painful procedure that can be performed under sufficient sedation with propofol and opioids. However, this sedation approach comes with a high risk of sedation-related adverse events (SRAEs). Esketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, causes less cardiorespiratory depression than opioids. The aim of this study was to assess the efficacy and safety of adding a low dose of esketamine to propofol and sufentanil sedation as an opioid-reduced regimen.

METHODS

A total of 122 consecutive patients with ASA I-II, body mass index < 30, and STOP-BANG score < 3 who underwent cervical conization were enrolled and randomly divided into Group S and Group ES. Using a closed-loop target-controlled infusion (TCI) pump with a target bispectral index (BIS) value of 60 ± 5, patients in Group S were sedated with 0.2 mcg·kg-1 sufentanil and propofol, while patients in Group ES were sedated with 0.15 mg·kg-1 esketamine, 0.1 mcg·kg-1 sufentanil and propofol. The primary outcome was the incidence and severity of SRAEs, while the secondary outcomes included effectiveness of sedation, awakening time, psychotomimetic side effects, postoperative pain, postoperative nausea and vomiting, and patient and gynaecologist satisfaction.

RESULTS

Data from 120 patients were analysed. The incidence of composite SRAEs was significantly higher in Group S than in Group ES (85.0% vs. 56.7%, P < 0.05). Furthermore, the severity of SRAEs was higher in Group S than in Group ES (P < 0.001). There were no significant differences in the effectiveness of sedation, awakening time, psychotomimetic side effects, postoperative pain, postoperative nausea and vomiting, or patient and gynaecologist satisfaction between the two groups.

CONCLUSION

Adding low-dose esketamine to propofol and sufentanil sedation reduces the incidence and severity of SRAEs in patients undergoing cervical conization, with equal sedation efficacy, recovery quality, and no additional psychomimetic side effects.

TRIAL REGISTRATION

ChiCTR2000040457 , 28/11/2020.

Disturbance of Key Cellular Subproteomes upon Propofol Treatment Is Associated with Increased Permeability of the Blood-Brain Barrier

Background: Propofol is a short-acting anesthetic, which is often used for induction and maintenance of general anesthesia, sedation for mechanically ventilated adults and procedural sedation. Several side effects of propofol are known and a substantial number of patients suffer from post-operative delirium after propofol application. In this study, we analyzed the effect of propofol on the function and protein expression profile on a proteome-wide scale. Methods: We cultured human brain microvascular endothelial cells in absence and presence of propofol and analyzed the permeability of the blood-brain barrier (BBB) by fluorescein passage and protein abundance on a proteome-wide scale by mass spectrometry. Results: Propofol interfered with the function of the blood-brain barrier. This was not due to decreased adhesion of propofol-treated human brain microvascular endothelial cells. The proteomic analysis revealed that some key pathways in these cells were disturbed, such as oxygen metabolism, DNA damage recognition and response to stress. Conclusions: Propofol has strong effects on protein expression which could explain several side effects of propofol.

Effectiveness of virtual reality immersion on procedure-related pain and anxiety in outpatient pain clinic: an exploratory randomized controlled trial

Background

The study investigated virtual reality (VR) immersion in alleviating procedure-related pain in patients with chronic pain undergoing fluoroscopy-guided minimally-invasive intervention in a prone position at an outpatient clinic.

Methods

In this prospective randomized controlled study, 38 patients undergoing lumbar sympathetic ganglion block were randomized into either the VR or the control group. In the VR group, procedure-related pain was controlled via infiltration of local anesthetics while watching a 30-minute VR hypnotic program. In the control group, the skin infiltration alone was used, with the VR device switched off. The primary endpoint was an 11-point score on the numerical rating scale, indicating procedure-related pain. Patients’ satisfaction with pain control, anxiety levels, the need for additional local anesthetics during the procedure, hemodynamic stability, and any adverse events were assessed.

Results

Procedure-related pain was significantly lower in the VR group (3.7 ± 1.4) than in the control group (5.5 ± 1.7; P = 0.002). Post-procedural anxiety was lower in the VR group than in the control group (P = 0.025), with a significant reduction from pre-procedural anxiety (P < 0.001). Although patients’ satisfaction did not differ significantly (P = 0.158) between the groups, a higher number of patients required additional local anesthetics in the control group (n = 13) than in the VR group (n = 4; P = 0.001). No severe adverse events occurred in either group during the study.

Conclusions

VR immersion can be safely used as a novel adjunct to reduce procedural pain and anxiety during fluoroscopic pain intervention.

Antiviral Efficacy of the Anesthetic Propofol against Dengue Virus Infection and Cellular Inflammation

Propofol, 2,6-diisopropylphenol, is a short-acting intravenous sedative agent used in adults and children. Current studies show its various antimicrobial as well as anti-inflammatory effects. Dengue virus (DENV) is an emerging infectious pathogen transmitted by mosquitoes that causes mild dengue fever and progressive severe dengue diseases. In the absence of safe vaccines and antiviral agents, adjuvant treatments and supportive care are generally administered. This study investigated the antiviral effects of propofol against DENV infection and cellular inflammation by using an in vitro cell model. Treatment with propofol significantly inhibited DENV release 24 h postinfection in BHK-21 cells. Furthermore, it also blocked viral protein expression independent of the translational blockade. Propofol neither caused inhibitory effects on endosomal acidification nor prevented dsRNA replication. Either the proinflammatory TNF-α or the antiviral STAT1 signaling was reduced by propofol treatment. These results provide evidence to show the potential antiviral effects of the sedative propofol against DENV infection and cellular inflammation.

Use of BRASS in sedated critically-ill patients as a predictable mortality factor: BRASS-ICU

Objectives: To demonstrate that a BRASS score≥ 3 at admission of intubated, ventilated and sedated patients is predictive of mortalityMethods: we have realized an Observational prospective multicenter study.All Major patients without neurological history, admitted to ICU for a non-neurological cause, sedated and admitted under mechanical ventilation were included.Results: One hundred and ten patients were included, the BRASS score as well as the FOUR and RASS scores were collected.At day 28, patients with a BRASS score ≥ 3 had an excess mortality (OR 3.29 - CI 95% [1.42-7.63], p = 0.005) as well as day 90 (OR 2.65 - CI 95% [1.19-5.88], p = 0.02), without impact on the delirium measured by CAM-ICU (OR 1.8 - CI 95% [0.68-4.77], p = 0.023). After adjustment with SAPS II, FOUR and RASS, difference in mortality was not any more different.It is also noted that patients with BRASS ≥ 3 are more sedated (RASS: -5 [-5 - -5] vs -4 [-5 - -3], p < 0.0001) and more comatose (FOUR: 2 [1-4] vs 6 [4-9], p < 0.0001), and have higher doses of midazolam (10 mg/h [5-15] vs 7.5 mg/h [5-10], p = 0.02) and sufentanil (20 μg/h [15-22.5] vs 10 [10-12.5], p = 0.01).Conclusions: The early alteration of brainstem reflexes measured by the BRASS score was not independently predictable in terms of mortality in the non-neurological ICU patients, admitted under sedation and mechanical ventilation.Trial registration: ClinicalTrials.gov Identifier: NCT03835091,Registered 8 February 2019 - prospectively registered, https://clinicaltrials.gov/ct2/show/NCT03835091.

Effect-site concentration of remifentanil for preventing propofol injection pain during induction of balanced anesthesia

Background

Despite various strategies designed for preventing pain from propofol injection, it is still common and distressing to the patients. The purpose of the present study was to investigate the adequate effect-site concentration (Ce) of remifentanil to prevent pain due to propofol injection.

Methods

A total of 160 adults scheduled for elective surgery were randomly assigned to one of four groups receiving normal saline (group S) or remifentanil at a Ce of 2 (group R2), 3 (group R3), or 4 ng/ml (group R4), administered via target-controlled infusion, followed by the injection of 2 mg/kg of propofol (delivered with 1% lipid propofol). The severity and incidence of injection pain were assessed on a four-point scale.

Results

The incidence of propofol injection pain was significantly lower in group R2, R3, or R4 than in group S (30%, 5%, or 2.5% vs. 70%, respectively). Moreover, the intensity of the pain was lesser in group R2, R3, or R4 than in group S. However, the incidence or severity of injection was not different between groups R3 and R4.

Conclusions

During the induction of balanced anesthesia using propofol injection, pretreatment with remifentanil at a target Ce of 3 ng/ml effectively reduced propofol injection pain in adults.

Virtual Reality Distraction during Endoscopic Urologic Surgery under Spinal Anesthesia: A Randomized Controlled Trial

Sedation protocols during spinal anesthesia often involve sedative drugs associated with complications. We investigated whether virtual reality (VR) distraction could be applied during endoscopic urologic surgery under spinal anesthesia and yield better satisfaction than pharmacologic sedation. VR distraction without sedative was compared with pharmacologic sedation using repeat doses of midazolam 1–2 mg every 30 min during urologic surgery under spinal anesthesia. We compared the satisfaction of patients, surgeons, and anesthesiologists, as rated on a 5-point prespecified verbal rating scale. Two surgeons and two anesthesiologists rated the scale and an overall score was reported after discussion. Thirty-seven patients were randomized to a VR group (n = 18) or a sedation group (n = 19). The anesthesiologist’s satisfaction score was significantly higher in the VR group than in the sedation group (median (interquartile range) 5 (5–5) vs. 4 (4–5), p = 0.005). The likelihood of both patients and anesthesiologists being extremely satisfied was significantly higher in the VR group than in the sedation group. Agreement between the scores for surgeons and those for anesthesiologists was very good (kappa = 0.874 and 0.944, respectively). The incidence of apnea was significantly lower in the VR group than in the sedation group (n = 1, 5.6% vs. n = 7, 36.8%, p = 0.042). The present findings suggest that VR distraction is better than drug sedation with midazolam in terms of patient’s and anesthesiologist’s satisfaction and avoiding the respiratory side effects of midazolam during endoscopic urologic surgery under spinal anesthesia.

Intraoperative Awareness and Recall: A Comparative Study of Dexmedetomidine and Propofol in Cardiac Surgery

Background Awareness during general anesthesia is undesired and unanticipated patient wakefulness during surgery or recall of intraoperative events. Incidence of awareness in patients undergoing cardiac surgery is significantly higher than the overall incidence of 1% during general surgery. Awareness during cardiac surgery can be prevented by a number of methods. One such method is the supplemental, intraoperative use of sedative agents. Propofol, a bisubstituted phenol, is an intravenous general anesthetic that has been shown to reduce the incidence of awareness. Dexmedetomidine-an alpha₂-adrenergic agonist with anxiolytic, opioid, and general anesthetic-sparing properties-is being considered for maintaining intraoperative depth of anesthesia. The purpose of this study was to evaluate the effect of dexmedetomidine on depth of anesthesia and to compare it with the effect of propofol in cardiac surgery. Methods This was a prospective, randomized, double-blind study conducted in a tertiary-care hospital. Sixty patients with American Society of Anesthesiologists (ASA) physical status I-III planned for elective open heart surgery were randomized into two groups of 30 patients each. Each patient of the dexmedetomidine group received an initial loading dose of dexmedetomidine at 1 mcg kg^-1 over 10 minutes followed by infusion at the rate of 0.2-0.6 mcg kg^-1 hr^-1. Patients of the propofol group received propofol infusion at the rate of 0.25^-1 mg kg^-1 hr^-1. An identical technique-of standard general anesthesia and routine physiological monitoring-was used in both groups. Bispectral scores were recorded at predetermined intervals during surgery and the target bispectral index (BIS) was kept at 50±10. The patients were assessed for awareness and recall 24 hours after tracheal extubation using the Brice Questionnaire. Results Intraoperative BIS scores remained within the target range in both groups; however, the BIS scores showed variable trends between the groups and were significantly lower in the dexmedetomidine group (p < 0.001). None of the patients in either group had recall of intraoperative events. Conclusion Administration of dexmedetomidine was as effective in reducing awareness and recall in cardiac surgery compared to propofol. Thus, dexmedetomidine can be used as an alternative sedative agent to prevent awareness and recall in cardiac surgery.

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.

Antipsychotic-Induced Neuroleptic Malignant Syndrome After Cardiac Surgery

We report a case of neuroleptic malignant syndrome (NMS) in a postoperative cardiac surgery patient after the administration of typical and atypical antipsychotics for the treatment of delirium. On postoperative day 8, the patient's temperature peaked at 40.6°C. Agitation, rigidity, elevation in creatine kinase, and leukocytosis were associated findings. NMS was suspected on postoperative day 10. All antipsychotics were discontinued; dantrolene infusions and fluid therapy were initiated. After 2 days of NMS treatment, the patient's symptoms resolved. The temporal relationship between discontinuation of all antipsychotics, initiation of dantrolene, and clinical improvement supports the diagnosis of antipsychotic-induced NMS.

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.

Assessment and Management of Delirium in Older Adults in the Emergency Department: Literature Review to Inform Development of a Novel Clinical Protocol

Delirium occurs frequently in older patients in the emergency department (ED), is underrecognized, and has potentially serious consequences. Despite its seriousness, delirium is frequently missed by emergency providers, and patients with unrecognized delirium are often discharged from the ED. Even when it is appropriately recognized, managing delirium in older adults poses a significant challenge for ED providers. Geriatric delirium is typically caused by the interaction of multiple factors, including several that are commonly missed: pain, urinary retention, constipation, dehydration, and polypharmacy. Appropriate management includes nonpharmacological management with medication intervention reserved for emergencies. We have developed a new, comprehensive, evidence-based protocol for diagnosis/recognition, management, and disposition of geriatric delirium patients in the ED with a focus on identifying and treating commonly missed contributing causes.

The impact of dexmedetomidine infusion in sparing morphine consumption in off-pump coronary artery bypass grafting

PURPOSE

Recovery from off-pump coronary artery bypass (OPCAB) has been reported to be more advantageous than conventional coronary artery bypass grafting with regard to both hospital and intensive care unit length of stay. Dexmedetomidine is a selective α-2 agonist that has been used successfully as an adjunct to narcotics in adult and pediatric cardiac surgery. The aim of this study was to assess the effect of dexmedetomidine on the recovery, total narcotic consumption, and total hospital and intensive care unit length of stay in patients undergoing OPCAB.

METHODS

The recovery, hospital and intensive care unit length of stay, as well as total morphine consumption of patients receiving dexmedetomidine infusion (0.5 µg/kg/h; dexmedetomidine group), after induction of general anesthesia, were compared with those receiving placebo (saline group).

RESULTS

The duration of intubation of patients in the dexmedetomidine group was significantly shorter than in the control group (289 ± 44 minutes in the dexmedetomidine group vs 530 ± 119 minutes in the control group). The total hospital and intensive care unit length of stay were significantly shorter in the dexmedetomidine group (P < .05). Also, total fentanyl and morphine consumptions were lower in the dexmedetomidine group than in the control group (P < .05).

CONCLUSION

Our study showed that dexmedetomidine might be an effective adjuvant in reducing both total hospital and intensive care unit length of stay in patients undergoing OPCAB. Dexmedetomidine might play a role in reducing total morphine and fentanyl consumption in OPCAB.

Clinical and critical care concerns in severely ill obese patient

The incidence of obesity has acquired an epidemic proportion throughout the globe. As a result, increasing number of obese patients is being presented to critical care units for various indications. The attending intensivist has to face numerous challenges during management of such patients. Almost all the organ systems are affected by the impact of obesity either directly or indirectly. The degree of obesity and its prolong duration are the main factors which determine the harmful effect of obesity on human body. The present article reviews few of the important clinical and critical care concerns in critically ill obese patients.

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.

The role of the emergency pharmacist in trauma resuscitation

The clinical pharmacist in the emergency department is now commonly incorporated as a member of the emergency department trauma team. As such, the emergency pharmacist needs to have detailed knowledge of the pharmacotherapy of resuscitation and be able to apply the skills needed to function as a valuable member of this team. In addition to the traditional skills of the discipline of clinical pharmacy, the emergency pharmacist must be familiar with the intricacies of treating life-threatening injuries in an emergent setting and be able to anticipate the direction of the patient's care. The ability to provide valuable pharmacological interventions throughout the resuscitation and stabilization process requires familiarity with the process of resuscitation, including rapid sequence induction, analgesia and sedation, seizure prophylaxis, appropriate antibiotic and tetanus prophylaxis, intracranial pressure control, hemodynamic stabilization, and any other specific drug therapy that the clinical situation demands. This article discusses the aforementioned pharmacotherapeutic topics and describes the role of the Emergency Pharmacist on the ED trauma team.

Cardiovascular manifestations of sedatives and analgesics in the critical care unit

There are numerous sedatives and analgesics used in critical care medicine today; these medications are used on critically ill patients, many of whom have heart disease, including coronary artery disease or congestive heart failure. The purpose of this review is to recognize the effects of these medications on the heart. Studies that evaluated the effects of sedatives and analgesics on normal individuals or on those with heart disease were reviewed. Current choices for sustained sedation in the critically ill include the benzodiazepines, morphine, propofol, and etomidate. Each of these medications has their particular advantages and disadvantages. Benzodiazepines provide the greatest amnesia and cardiovascular safety but they can cause significant hypotension in the hemodynamically unstable patient. Morphine provides analgesia and cardioprotective activity after ischemia, although the large observational study CRUSADE showed increased mortality rate in those patients with non-ST segment elevation myocardial infarction who received morphine. Propofol is the most easily titratable drug with cardioprotective features, but its use must be accompanied with great attention to possible development of propofol infusion syndrome, which is a deadly disease, especially in patients with head injury and those with septic shock receiving vasopressors. Etomidate has a rapid onset effect and short period of action with great hemodynamic stability even in patients with shock and hypovolemia, but the incidence of adrenal insufficiency during infusion, not bolus doses, may cause deterioration in the circulatory stability. In conclusion, the sedatives and analgesics mentioned here have characteristics that give them a cardiovascular safety profile useful in critically ill patients. However, use of these drugs on an individual basis is dependent on each agent's safety and efficacy.

Propofol infusion syndrome: an overview of a perplexing disease

Propofol (2, 6-diisopropylphenol) is a potent intravenous hypnotic agent that is widely used in adults and children for sedation and the induction and maintenance of anaesthesia. Propofol has gained popularity for its rapid onset and rapid recovery even after prolonged use, and for the neuroprotection conferred. However, a review of the literature reveals multiple instances in which prolonged propofol administration (>48 hours) at high doses (>4 mg/kg/h) may cause a rare, but frequently fatal complication known as propofol infusion syndrome (PRIS). PRIS is characterized by metabolic acidosis, rhabdomyolysis of both skeletal and cardiac muscle, arrhythmias (bradycardia, atrial fibrillation, ventricular and supraventricular tachycardia, bundle branch block and asystole), myocardial failure, renal failure, hepatomegaly and death. PRIS has been described as an 'all or none' syndrome with sudden onset and probable death. The literature does not provide evidence of degrees of symptoms, nor of mildness or severity of signs in the clinical course of the syndrome. Recently, a fatal case of PRIS at a low infusion rate (1.9-2.6 mg/kg/h) has been reported. Common laboratory and instrumental findings in PRIS are myoglobinuria, downsloping ST-segment elevation, an increase in plasma creatine kinase, troponin I, potassium, creatinine, azotaemia, malonylcarnitine and C5-acylcarnitine, whereas in the mitochondrial respiratory electron transport chain, the activity of complex IV and cytochrome oxidase ratio is reduced. Propofol should be used with caution for sedation in critically ill children and adults, as well as for long-term anesthesia in otherwise healthy patients, and doses exceeding 4-5 mg/kg/h for long periods (>48 h) should be avoided. If PRIS is suspected, propofol must be stopped immediately and cardiocirculatory stabilization and correction of metabolic acidosis initiated. So, PRIS must be kept in mind as a rare, but highly lethal, complication of propofol use, not necessarily confined to its prolonged use. Furthermore, the safe dosage of propofol may need re-evaluation, and new studies are needed.

Traumatic brain injury: an integrated clinical case presentation and literature review part II: the continuum of care

The following paper continues the presentation of a case scenario outlining the assessment, interventions and outcome of a person who sustained multiple trauma with a focus on traumatic brain injury (TBI). Part I explored assessment and initial management of the patient from pre-hospital care through to the emergency department and operating theatre. Part II describes the intensive care period as an integral component of the continuum of care. Key issues in the case are presented sequentially with relevant theory integrated and applied to the clinical case throughout the discussion with a focus on the complex physiological, psychological, and spiritual needs of the patient and their family.

Medical management of cerebral edema

✓Cerebral edema is frequently encountered in clinical practice in critically ill patients with acute brain injury from diverse origins and is a major cause of increased morbidity and death in this subset of patients. The consequences of cerebral edema can be lethal and include cerebral ischemia from compromised regional or global cerebral blood flow (CBF) and intracranial compartmental shifts due to intracranial pressure gradients that result in compression of vital brain structures. The overall goal of medical management of cerebral edema is to maintain regional and global CBF to meet the metabolic requirements of the brain and prevent secondary neuronal injury from cerebral ischemia. Medical management of cerebral edema involves using a systematic and algorithmic approach, from general measures (optimal head and neck positioning for facilitating intracranial venous outflow, avoidance of dehydration and systemic hypotension, and maintenance of normothermia) to specific therapeutic interventions (controlled hyperventilation, administration of corticosteroids and diuretics, osmotherapy, and pharmacological cerebral metabolic suppression). This article reviews and highlights the medical management of cerebral edema based on pathophysiological principles in acute brain injury.

Addition of dexmedetomidine to standard sedation regimens after cardiac surgery: an outcomes analysis

STUDY OBJECTIVE

To characterize inpatient use of intravenous sedatives in the real-world setting, and to evaluate clinical and economic outcomes when dexmedetomidine was used with midazolam and propofol for select cardiovascular procedures.

DESIGN

12-month retrospective analysis.

DATA SOURCE

An administrative claims database of operational data from a nationally representative sample of 250 medical and surgical hospitals.

PATIENTS

Patients who received midazolam plus propofol (9996 patients) or dexmedetomidine, midazolam, plus propofol (356 patients) after cardiac valve or vessel surgery.

MEASUREMENTS AND MAIN RESULTS

The source of patient demographics (e.g., age, sex, Charlson Comorbidity Index) and outcomes (e.g., charges, length of stay, mortality rate) was the hospital billing claim form. Patients in the dexmedetomidine-midazolam-propofol cohort tended to be younger and male and to have fewer comorbidities than those midazolam-propofol cohort. The primary outcomes for the three-drug cohort showed significant reductions in total charges/patient (approximately $18,000, p<0.05), total hospital length of stay (0.6 days, p<0.0001), days in the intensive care unit or cardiac care unit (3.87 days, p<0.0001), and mortality (2%, p=0.0142). Although pharmacy charges were higher (approximately $4000/patient), lower charges for the intensive care or cardiac care unit, operating room, room and board, and respiratory services were observed in the dexmedetomidinemidazolam-propofol cohort compared with the two-drug cohort. Also, mechanical ventilation was shorter by approximately 0.5 day in the three-drug cohort (p<0.01).

CONCLUSION

These initial findings of a real-world assessment of dexmedetomidine use with other agents suggest favorable clinical and economic outcomes. Further research through randomized clinical trials of dexmedetomidine is warranted to better understand its optimum patient population, dosage, and the causality of the results, and to confirm the potential clinical and economic benefits observed in our patients.

Economic evaluation of sustained sedation/analgesia in the intensive care unit

Lorazepam, midazolam, propofol and opioids are the primary agents that are used for sustained sedation and analgesia of critically ill patients. The choice of agent depends on safety profiles, expected outcomes, cost, patient characteristics and clinical experience. Few studies have comparatively evaluated the sedatives in terms of cost. Many factors, aside from drug costs, influence the total cost of sedation in the intensive care unit. This article reviews the cost parameters of intensive care unit sedation that are specific to the characteristics of commonly used sedatives and analgesics, evaluates economic studies and cost models, summarises alternative methods of sedation and analgesia, and provides practical recommendations for methods of cost containment, including daily sedation interruption, sedation monitoring and protocol implementation.

General versus spinal anesthesia with different forms of sedation in patients undergoing radical retropubic prostatectomy: Results of a prospective, randomized study

AIM

To assess the impact of spinal anesthesia (SpA) combined with three different forms of conscious sedation on intraoperative and postoperative outcome in patients undergoing radical retropubic prostatectomy (RRP) for organ confined prostate cancer (pCa).

METHODS

A total of 121 consecutive patients with pCa undergoing RRP were randomized into four groups. They were randomized as follows: group 1 (general anesthesia: 34 patients), group 2 (lumbar 2 to lumbar 3 interspace SpA with diazepam as sedative agent: 28), group 3 (SpA with propofol: 30), and group 4 (SpA with midazolam: 29). Intraoperative and perioperative parameters were collected.

RESULTS

The present study showed that muscle relaxation throughout RRP was not different in the four groups; bleeding was significantly (P = 0.04) lower with SpA, regardless of the form of sedation. Group 3 patients reported the best postoperative oxygen saturation percentage by pulse oximetry and sedation score (P = 0.02; d.f. = 3 and P < 0.0001; d.f. = 3, respectively), the shortest waiting time in the postoperative holding area (P < 0.001; d.f. = 3), the lowest pain on postoperative day 1 (P = 0.0004; d.f. = 3), and the highest frequency of first flatus passage (P = 0.0001; d.f. = 3). A higher number of group 4 patients were able to carry out unassisted ambulation (P < 0.0001; d.f. = 3).

CONCLUSIONS

Conscious sedation coupled with SpA is a safe, reliable and effective procedure for patients undergoing RRP. The use of propofol as sedative agent offers several advantages both over other types of conscious sedation and general anesthesia.

Excitatory and inhibitory actions of isoflurane in bovine chromaffin cells

Isoflurane, a halogenated volatile anesthetic, is thought to produce anesthesia by depressing CNS function. Many anesthetics, including isoflurane, are thought to modulate and/or directly activate GABA(A) receptors. Chromaffin cells are known to express functional GABA(A) receptors. We previously showed that activation of the GABA(A) receptors, with specific agonists, leads to cellular excitation resulting from the depolarized anion equilibrium potential. In this study, our goal was to determine whether isoflurane mimicked this response and to explore the functional consequences of this activation. Furthermore, we sought to study the actions of isoflurane on nicotinic acetylcholine receptors (nAChRs) as they mediate the "sympathetic drive" in these cells. For these studies the Ca(2+)-indicator dye fura-2 was used to assay [Ca(2+)](i). Amperometric measurements were used to assay catecholamine release. We show that bovine adrenal chromaffin cells were excited by isoflurane at clinically relevant concentrations. Isoflurane directly activated GABA(A) receptors found in chromaffin cells, which depolarized the cells and elevated [Ca(2+)](i). Application of isoflurane directly to the chromaffin cells elicited catecholamine secretion from these cells. At the same time, isoflurane suppressed activation of nAChRs, which presumably blocks "sympathetic drive" to the chromaffin cells. These latter results may help explain why isoflurane produces the hypotension observed clinically.

Repeated dexmedetomidine infusions, a postoperative living-donor liver transplantation patient

Here we report on a postoperative living-donor liver transplantation (LDLT) patient who received nightly infusions of dexmedetomidine (DEX), a specific alpha2-adrenergic receptor agonist, to treat agitation and insomnia during an intensive care unit stay. The infusion rate was adjusted according to the Ramsay sedation score. The actual plasma concentrations were higher than the values predicted by RugLoop software package simulation 9 h after the DEX infusion. However, all of the measurements were within the therapeutic range for DEX. Thus, DEX infusion could be safely used in the postoperative LDLT patient by employing a simple consciousness scale.

Sedation and comfort issues in the ventilated infant and child

Intubated infants and children require optimal sedation and comfort measures. Key elements that ensure the provision of quality care for these patients include the use of pain, comfort, and sedation assessment tools; pharmacologic and nonpharmacologic strategies; and the inclusion of the patient and parents as part of the team. This article describes approaches for using sedation and ensuring comfort in these patients. Application of research and the education of team members and the patient and family are crucial aspects of care and are also discussed.

Sedation, analgesia, and neuromuscular blockade in sepsis: An evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for sedation, analgesia, and neuromuscular blockade in sepsis that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

There is no preferred sedative or analgesic agent for use in the critically ill septic patient during mechanical ventilation. Protocols should be utilized for administration of sedation with predefined sedation scale targets. Either intermittent bolus sedation or continuous infusion sedation to predetermined end points with daily interruption/lightening of continuous infusion sedation with awakening and re-titration, if necessary, are recommended. Neuromuscular blockade should be avoided if possible and, if used continuously, requires twitch monitoring.

Etomidate elevates intracellular calcium levels and promotes catecholamine secretion in bovine chromaffin cells

Etomidate, an intravenous imidazole general anaesthetic, is thought to produce anaesthesia by modulating or activating ionotropic Cl(-)-permeable GABA(A) receptors. Chromaffin cells are known to express functional GABA(A) receptors with properties similar to their neuronal counterparts. We have shown that activation of the GABA(A) receptors, with specific GABA(A) agonists, leads to cellular excitation. Our goal was to determine whether etomidate mimicked this response and to explore the functional consequences of this activation. Imaging experiments with the Ca(2+)-indicator dye fura-2 were used to assay [Ca(2+)](i). Bovine adrenal chromaffin cells were superfused with a variety of GABA(A)-selective drugs to determine their effects on [Ca(2+)](i). Amperometric measurements were used to assay catecholamine release in real-time. We show that bovine adrenal chromaffin cells were excited by etomidate at clinically relevant concentrations. Etomidate directly activated GABA(A) receptors found in chromaffin cells thereby elevating [Ca(2+)](i). The effects of etomidate were mimicked by the specific GABA(A) agonist muscimol and blocked by the specific antagonist bicuculline. Our data show that low concentrations of etomidate modulated GABA(A) receptor activation by muscimol. Blockade of voltage-dependent Ca(2+) channels prevented the elevation of [Ca(2+)](i) by GABA. Application of etomidate directly to the chromaffin cells elicited robust catecholamine secretion from these cells. The data indicate that clinically relevant concentrations of etomidate can directly activate GABA(A) receptors, which, due to the positive anion equilibrium potential, depolarizes chromaffin cells. This depolarization activates voltage-dependent Ca(2+) channels thereby stimulating catecholamine release. Our data suggest that circulating catecholamine levels may be elevated after etomidate application.

Clinical management of cardiogenic shock associated with prolonged propofol infusion

This case report details the development of cardiogenic shock after craniotomy in a patient sedated with a propofol infusion. The patient survived with the assistance of extracorporeal membrane oxygenation. A literature review summarizes the syndrome of cardiogenic shock associated with prolonged propofol infusion. This is the first report of survival in this syndrome resuiting from mechanical circulatory support.

Cardiovascular and parasympathetic effects of dexmedetomidine in healthy subjects

We evaluated the cardiovascular effects of intravenously (i.v.) and buccally administered dexmedetomidine, a selective α2-adrenoceptor agonist. Six healthy male subjects were studied unmedicated and after 2 µg/kg i.v. or buccal doses of dexmedetomidine, using repeated recordings of ECG and blood pressure. Cardiac parasympathetic activity was estimated by measurements of high-frequency (HF) heart rate variability. Intravenous, but not buccal, dexmedetomidine raised systolic blood pressure by 11 ± 5 mmHg (mean ± SEM) and diastolic by 16 ± 3 mmHg (maxima at 10 min). Later on, both i.v., and buccal dexmedetomidine produced a very similar hypotensive effect: on average, [Formula: see text]10 mmHg reductions in systolic and diastolic pressure at 3 h. Intravenous dosing was followed by a decline in heart rate (–11 ± 2 beats/min) accompanied by a trend toward enhanced HF variability (maximal effect at 10 min), which probably reflected baroreflex-mediated parasympathetic efferent neuronal activation. Buccal dexmedetomidine increased significantly the HF variability (maximum at 45 min) without influencing heart rate. We conclude that dexmedetomidine, when administered by a method that avoids concentration peaks, e.g., buccal dosing, can be used to produce a prolonged augmentation of cardiac parasympathetic efferent neuronal activity.Key words: dexmedetomidine, parasympathetic nervous system, heart rate, blood pressure.

Bioavailability of dexmedetomidine after extravascular doses in healthy subjects

AIM

To determine the absolute bioavailability of extravascularly administered dexmedetomidine, a novel a2-adrenoceptor agonist, in healthy subjects.

METHODS

Single 2 microg x kg-1 doses of dexmedetomidine were given intravenously, intramuscularly, perorally and buccally (where the solution is not swallowed) to 12 healthy male subjects. The drug concentration-time data were analysed using linear one-compartment (buccal and peroral data), or two-compartment modelling (intravenous data), or noncompartmental methods (intramuscular data).

RESULTS

Mean (95% CI) absolute bioavailability after peroral, buccal and intramuscular administration was 16% (12-20%), 82% (73-92%) and 104% (96-112%), respectively.

CONCLUSION

Dexmedetomidine is well absorbed systemically through the oral mucosa, and therefore buccal dosing may provide an effective, noninvasive route to administer the drug.

Sedation in neurointensive care: advances in understanding and practice

PURPOSE OF REVIEW

To evaluate the rationale and the pharmacologic options for sedating neurointensive care patients.

RECENT FINDINGS

Sedation is a fundamental element in the neurointensive care unit. Even if the sedative strategy in the neurointensive care unit shares the same general aims with intensive care, the characteristics of the patients in the neurointensive care unit pose other unique challenges and some specific indications. The primary aim of neurointensive care is to maintain adequate cerebral perfusion pressure, to control intracranial pressure, and to maintain an adequate mean arterial pressure. Reducing the brain's metabolic demand is an important treatment strategy, and analgesic and sedative agents are used to prevent undesirable increases in intracranial pressure. There are many different pharmacologic agents available, each with distinct advantages and disadvantages.

SUMMARY

The pharmacokinetic and pharmacologic effects of the available sedatives used in neurointensive care patients are reviewed.