Effects of Fentanyl and S(+)-ketamine on Cerebral Hemodynamics, Gastrointestinal Motility, and Need of Vasopressors in Patients With Intracranial Pathologies

Ketamine analgo-sedation for mechanically ventilated critically ill adults: A rapid practice guideline from the Saudi Critical Care Society and the Scandinavian Society of Anesthesiology and Intensive Care Medicine

BACKGROUND

This Rapid Practice Guideline (RPG) aimed to provide evidence-based recommendations for ketamine analgo-sedation (monotherapy and adjunct) versus non-ketamine sedatives or usual care in adult intensive care unit (ICU) patients on invasive mechanical ventilation (iMV) and to identify knowledge gaps for future research.

METHODS

The RPG panel comprised 23 multinational multidisciplinary panelists, including a patient representative. An up-to-date systematic review and meta-analysis constituted the evidence base. The Grading Recommendations, Assessment, Development, and Evaluation approach, and the evidence-to-decision framework were used to assess the certainty of evidence and to move from evidence to decision/recommendation. The panel provided input on the balance of the desirable and undesirable effects, certainty of evidence, patients' values and preferences, costs, resources, equity, feasibility, acceptability, and research priorities.

RESULTS

Data from 17 randomized clinical trials (n = 898) and nine observational studies (n = 1934) were included. There was considerable uncertainty about the desirable and undesirable effects of ketamine monotherapy for analgo-sedation. The evidence was very low certainty and downgraded for risk of bias, indirectness, and inconsistency. Uncertainty or variability in values and preferences were identified. Costs, resources, equity, and acceptability were considered varied. Adjunctive ketamine therapy had no effect on mortality (within 28 days) (relative risk [RR] 0.99; 95% confidence interval [CI] 0.76 to 1.27; low certainty), and may slightly reduce iMV duration (days) (mean difference [MD] -0.05 days; 95% CI -0.07 to -0.03; low certainty), and uncertain effect on the cumulative dose of opioids (mcg/kg/h morphine equivalent) (MD -11.6; 95% CI -20.4 to -2.7; very low certainty). Uncertain desirable effects (cumulative dose of sedatives and vasopressors) and undesirable effects (adverse event rate, delirium, arrhythmia, hepatotoxicity, hypersalivation, use of physical restraints) were also identified. A possibility of important uncertainty or variability in patient-important outcomes led to a balanced effect that favored neither the intervention nor the comparison. Cost, resources, and equity were considered varied.

CONCLUSION

The RPG panel provided two conditional recommendations and suggested (1) against using ketamine as monotherapy analgo-sedation in critically ill adults on iMV when other analgo-sedatives are available; and (2) using ketamine as an adjunct to non-ketamine usual care sedatives (e.g., opioids, propofol, dexmedetomidine) or continuing with non-ketamine usual care sedatives alone. Large-scale trials should provide additional evidence.

Ketamine for Critically Ill Patients with Severe Acute Brain Injury: A Systematic Review with Meta-analysis and Trial Sequential Analysis of Randomized Clinical Trials

BACKGROUND

Patients with severe acute brain injury have a high risk of a poor clinical outcome due to primary and secondary brain injury. Ketamine reportedly inhibits cortical spreading depolarization, an electrophysiological phenomenon that has been associated with secondary brain injury, making ketamine potentially attractive for patients with severe acute brain injury. The aim of this systematic review is to explore the current literature regarding ketamine for patients with severe acute brain injury.

METHODS

We systematically searched international databases for randomized clinical trials comparing ketamine by any regimen versus placebo, no intervention, or any control drug for patients with severe acute brain injury. Two authors independently reviewed and selected trials for inclusion, extracted data, assessed risk of bias, and performed analysis using Review Manager and Trial Sequential Analysis. Evidence certainty was assessed using Grading of Recommendations Assessment, Development and Evaluation. The primary outcomes were the proportion of participants with an unfavorable functional outcome, the proportion of participants with one or more serious adverse events, and quality of life.

RESULTS

We identified five randomized trials comparing ketamine versus sufentanil, fentanyl, other sedatives, or saline (total N = 149 participants). All outcomes were at overall high risk of bias. The proportions of participants with one or more serious adverse events did not differ between ketamine and sufentanil or fentanyl (relative risk 1.45, 95% confidence interval 0.81-2.58; very low certainty). Trial sequential analysis showed that further trials are needed.

CONCLUSIONS

The level of evidence regarding the effects of ketamine on functional outcome and serious adverse events in patients with severe acute brain injury is very low. Ketamine may markedly, modestly, or not at all affect these outcomes. Large randomized clinical trials at low risk of bias are needed.

Influence of Intravenous S-Ketamine on the Pharmacokinetics of Oral Morphine in Healthy Volunteers

BACKGROUND

Subanesthetic ketamine may reduce perioperative consumption of opioids. We studied whether intravenous S-ketamine alters the pharmacokinetics of oral morphine in healthy volunteers.

METHODS

In this paired, randomized, double-blind, crossover trial, 12 participants under a 2-hour intravenous S-ketamine (0.57 mg/kg/h) or placebo infusion received oral morphine (0.2 mg/kg) at 30 minutes. Plasma concentrations of ketamine, morphine, and their major metabolites were quantified for 24 hours. The primary end point was area under the curve (AUC) 0-24 of morphine. Other pharmacokinetic variables for morphine and its metabolites were studied as secondary end points. The data were analyzed as between-phase comparisons for each participant using Wilcoxon matched-pairs signed-rank tests ( tmax ) or paired t -tests on log-transformed variables (other variables).

RESULTS

While the AUC 0-24 was similar between the 2 phases, S-ketamine reduced the AUC 0-1.5 of oral morphine by 69% (ratio to control, 0.31; 90% confidence interval [CI], 0.15-0.65; P = .0171) and increased its tmax from 0.5 (range, 0.50-1.5) to 1.0 hour (range, 0.50-4.0; P = .010). The AUC 0-1.5 of morphine-6-glucuronide (M6G) was reduced by 84% (0.16; 90% CI, 0.07-0.37; P = .0025) and maximum plasma concentration ( Cmax ) by 43% (0.57; 90% CI, 0.40-0.81; P = .0155), while its tmax was increased from 1.5 (range, 1.0-2.0) to 4.0 (range, 1.0-8.0; P = .0094) hours by S-ketamine. Similarly, the AUC 0-1.5 of morphine-3-glucuronide (M3G) was reduced by 85% (0.15; 90% CI, 0.05-0.43; P = .0083), and tmax increased from 1.0 (range, 0.5-1.5) to 4.0 hours (range, 1.0-8.0; P = .0063). In addition, the M6G-to-morphine and M3G-to-morphine metabolic AUC ratios were decreased by 47% (0.53; 90% CI, 0.39-0.71; P = .0033) and 52% (0.48; 90% CI, 0.27-0.85; P = .0043) during 0 to 1.5 hours and by 15% (0.85; 90% CI, 0.78-0.92; P = .0057) and 10% (0.90; 90% CI, 0.83-0.98; P = .0468) during 0 to 24 hours, respectively. One participant was excluded from the analyses due to vomiting in the S-ketamine phase.

CONCLUSIONS

Intravenous S-ketamine inhibited the metabolism of oral morphine and delayed its absorption, resulting in a net reduction in the exposure to morphine during the first 1.5 hours. Intravenous S-ketamine may delay the absorption and impair the efficacy of orally administered analgesics and other drugs.

The Impact of Sedative Choice on Intracranial and Systemic Physiology in Moderate to Severe Traumatic Brain Injury: A Scoping Review

Although sedative use is near-ubiquitous in the acute management of moderate to severe traumatic brain injury (m-sTBI), the evidence base for these agents is undefined. This review summarizes the evidence for analgosedative agent use in the intensive care unit management of m-sTBI. Clinical studies of sedative and analgosedative agents currently utilized in adult m-sTBI management (propofol, ketamine, benzodiazepines, opioids, and alpha-2 agonists) were identified and assessed for relevance and methodological quality. The primary outcome was the effect of the analgosedative agent on intracranial pressure (ICP). Secondary outcomes included intracranial hemodynamic and metabolic parameters, systemic hemodynamic parameters, measures of therapeutic intensity, and clinical outcomes. Of 594 articles identified, 61 met methodological review criteria, and 40 were included in the qualitative summary; of these, 33 were prospective studies, 18 were randomized controlled trials, and 8 were blinded. There was consistent evidence for the efficacy of sedative agents in the management of m-sTBI and raised ICP, but the overall quality of the evidence was poor, consisting of small studies (median sample size, 23.5) of variable methodological quality. Propofol and midazolam achieve the goals of sedation without notable differences in efficacy or safety, although high-dose propofol may disrupt cerebral autoregulation. Dexmedetomidine and propofol/ dexmedetomidine combination may cause clinically significant hypotension. Dexmedetomidine was effective to achieve a target sedation score. De novo opioid boluses were associated with increased ICP and reduced cerebral perfusion pressure. Ketamine bolus and infusions were not associated with increased ICP and may reduce the incidence of cortical spreading depolarization events. In conclusion, there is a paucity of high-quality evidence to inform the optimal use of analgosedative agents in the management of m-sTBI, inferring significant scope for further research.

Pharmacotherapy optimization for rapid sequence intubation in the emergency department

PURPOSE

Rapid-sequence intubation (RSI) is the process of administering a sedative and neuromuscular blocking agent (NMBA) in rapid succession to facilitate endotracheal intubation. It is the most common and preferred method for intubation of patients presenting to the emergency department (ED). The selection and use of medications to facilitate RSI is critical for success. The purpose of this review is to describe pharmacotherapies used during the RSI process, discuss current clinical controversies in RSI medication selection, and review pharmacotherapy considerations for alternative intubation methods.

SUMMARY

There are several steps to the intubation process requiring medication considerations, including pretreatment, induction, paralysis, and post-intubation sedation and analgesia. Pretreatment medications include atropine, lidocaine, and fentanyl; but use of these agents in clinical practice has fallen out of favor as there is limited evidence for their use outside of select clinical scenarios. There are several options for induction agents, though etomidate and ketamine are the most used due to their more favorable hemodynamic profiles. Currently there is retrospective evidence that etomidate may produce less hypotension than ketamine in patients presenting with shock or sepsis. Succinylcholine and rocuronium are the preferred neuromuscular blocking agents, and the literature suggests minimal differences between succinylcholine and high dose rocuronium in first-pass success rates. Selection between the two is based on patient specific factors, half-life and adverse effect profiles. Finally, medication-assisted preoxygenation and awake intubation are less common methods for intubation in the ED but require different considerations for medication use.

AREAS FOR FUTURE RESEARCH

The optimal selection, dosing, and administration of RSI medications is complicated, and further research is needed in several areas. Additional prospective studies are needed to determine optimal induction agent selection and dosing in patients presenting with shock or sepsis. Controversy exists over optimal medication administration order (paralytic first vs induction first) and medication dosing in obese patients, but there is insufficient evidence to significantly alter current practices regarding medication dosing and administration. Further research examining awareness with paralysis during RSI is needed before definitive and widespread practice changes to medication use during RSI can be made.

Acute Effects of Ketamine on Intracranial Pressure in Children With Severe Traumatic Brain Injury

OBJECTIVES

The acute cerebral physiologic effects of ketamine in children have been incompletely described. We assessed the acute effects of ketamine on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in children with severe traumatic brain injury (TBI).

DESIGN

In this retrospective observational study, patients received bolus doses of ketamine for sedation or as a treatment for ICP crisis (ICP > 20 mm Hg for > 5 min). Administration times were synchronized with ICP and CPP recordings at 1-minute intervals logged in an automated database within the electronic health record. ICP and CPP were each averaged in epochs following drug administration and compared with baseline values. Age-based CPP thresholds were subtracted from CPP recordings and compared with baseline values. Trends in ICP and CPP over time were assessed using generalized least squares regression.

SETTING

A 30-bed tertiary care children's hospital PICU.

PATIENTS

Children with severe TBI who underwent ICP monitoring.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We analyzed data from 33 patients, ages 1 month to 16 years, 22 of whom received bolus doses of ketamine, with 127 doses analyzed. Demographics, patient, and injury characteristics were similar between patients who did versus did not receive ketamine boluses. In analysis of the subset of ketamine doses used only for sedation, there was no significant difference in ICP or CPP from baseline. Eighteen ketamine doses were given during ICP crises in 11 patients. ICP decreased following these doses and threshold-subtracted CPP rose.

CONCLUSIONS

In this retrospective, exploratory study, ICP did not increase following ketamine administration. In the setting of a guidelines-based protocol, ketamine was associated with a reduction in ICP during ICP crises. If these findings are reproduced in a larger study, ketamine may warrant consideration as a treatment for intracranial hypertension in children with severe TBI.

Protecting the injured central nervous system: Do anesthesia or hypothermia ameliorate secondary injury?

Traumatic injury to the central nervous system (CNS) and stroke initiate a cascade of processes that expand the area of tissue loss. The current review considers recent studies demonstrating that the induction of an anesthetic state or cooling the affected tissue (hypothermia) soon after injury can have a therapeutic effect. We first provide an overview of the neurobiological processes that fuel tissue loss after traumatic brain injury (TBI), spinal cord injury (SCI) and stroke. We then examine the rehabilitative effectiveness of therapeutic anesthesia across a variety of drug categories through a systematic review of papers in the PubMed database. We also review the therapeutic benefits hypothermia, another treatment that quells neural activity. We conclude by considering factors related to the safety, efficacy and timing of treatment, as well as the mechanisms of action. Clinical implications are also discussed.

Co-administration of Ketamine in Pediatric Patients with Neurologic Conditions at Risk for Intracranial Hypertension

BACKGROUND

Ketamine has traditionally been avoided as an induction agent for tracheal intubation in patients with neurologic conditions at risk for intracranial hypertension due to conflicting data in the literature. The objective of this study was to evaluate and compare the effects of ketamine versus other medications as the primary induction agent on peri-intubation neurologic, hemodynamic and respiratory associated events in pediatric patients with neurologic conditions at risk for intracranial hypertension.

METHODS

This retrospective observational study enrolled patients < 18 years of age at risk for intracranial hypertension who were admitted to a quaternary children's hospital between 2015 and 2020. Associated events included neurologic, hemodynamic and respiratory outcomes comparing primary induction agents of ketamine versus non-ketamine for tracheal intubation.

RESULTS

Of 143 children, 70 received ketamine as the primary induction agent prior to tracheal intubation. Subsequently after tracheal intubation, all the patients received adjunct analgesic and sedative medications (fentanyl, midazolam, and/or propofol) at doses that were inadequate to induce general anesthesia but would keep them comfortable for further diagnostic workup. There were no significant differences between associated neurologic events in the ketamine versus non-ketamine groups (p = 0.42). This included obtaining an emergent computed tomography scan (p = 0.28), an emergent trip to the operating room within 5 h of tracheal intubation (p = 0.6), and the need for hypertonic saline administration within 15 min of induction drug administration for tracheal intubation (p = 0.51). There were two patients who had clinical and imaging evidence of herniation, which was not more adversely affected by ketamine compared with other medications (p = 0.49). Of the 143 patients, 23 had pre-intubation and post-intubation intracranial pressure values recorded; 11 received ketamine, and 3 of these patients had intracranial hypertension that resolved or improved, whereas the remaining 8 children had intracranial pressure within the normal range that was not exacerbated by ketamine. There were no significant differences in overall associated hemodynamic or respiratory events during tracheal intubation and no 24-h mortality in either group.

CONCLUSIONS

The administration of ketamine as the primary induction agent prior to tracheal intubation in combination with other agents after tracheal intubation in children at risk for intracranial hypertension was not associated with an increased risk of peri-intubation associated neurologic, hemodynamic or respiratory events compared with those who received other induction agents.

Advantages of ketamine in pediatric anesthesia

Although ketamine is primarily used for induction and maintenance of general anesthesia, it also presents sedative, amnestic, anesthetics, analgesic, antihyperalgesia, neuroprotective, anti-inflammatory, immunomodulant, and antidepressant effects. Its unique pharmacodynamics and pharmacokinetic properties allow the use of ketamine in various clinical settings including sedation, ambulatory anesthesia, and intensive care practices. It has also adopted to manage acute and chronic pain management. Clinically, ketamine produces dissociative sedation, analgesia, and amnesia while maintaining laryngeal reflexes, with respiratory and cardiovascular stability. Notably, it does not cause respiratory depression, maintaining both the hypercapnic reflex and the residual functional capacity with a moderate bronchodilation effect. In the pediatric population, ketamine can be administered through practically all routes, making it an advantageous drug for the sedation required setting such as placement of difficult vascular access and in uncooperative and oppositional children. Consequently, ketamine is indicated in prehospital induction of anesthesia, induction of anesthesia in potentially hemodynamic unstable patients, and in patients at risk of bronchospasm. Even more, ketamine does not increase intracranial pressure, and it can be safely used also in patients with traumatic brain injuries. This article is aimed to provide a brief and practical summary of the role of ketamine in the pediatric field.

Ketamine Boluses Are Associated with a Reduction in Intracranial Pressure and an Increase in Cerebral Perfusion Pressure: A Retrospective Observational Study of Patients with Severe Traumatic Brain Injury

Background

Increased intracranial pressure (ICP) and hypotension have long been shown to lead to worse outcomes in the severe traumatic brain injury (TBI) population. Adequate sedation is a fundamental principle in TBI care, and ketamine is an attractive option for sedation since it does not commonly cause systemic hypotension, whereas most other sedative medications do. We evaluated the effects of ketamine boluses on both ICP and cerebral perfusion pressure (CPP) in patients with severe TBI and refractory ICP.

Methods

We conducted a retrospective review of all patients admitted to the neurointensive care unit at a single tertiary referral center who had a severe traumatic brain injury with indwelling intracranial pressure monitors. We identified those patients with refractory intracranial pressure who received boluses of ketamine. We defined refractory as any sustained ICP greater than 20 mmHg after the patient was adequately sedated, serum Na was at goal, and CO₂ was maintained between 35 and 40 mmHg. The primary outcome was a reduction in ICP with a subsequent increase in CPP.

Results

The patient cohort consisted of 44 patients with a median age of 30 years and a median presenting Glasgow Coma Scale (GCS) of 5. The median reduction in ICP after administration of a ketamine bolus was −3.5 mmHg (IQR −9 to +1), and the postketamine ICP was significantly different from baseline (p < 0.001). Ketamine boluses led to an increase in CPP by 2 mmHg (IQR −5 to +12), which was also significantly different from baseline (p < 0.001).

Conclusion

In this single-institution study of patients with severe traumatic brain injury, ketamine boluses were associated with a reduction in ICP and an increase in CPP. This was a retrospective review of 43 patients and is therefore limited in nature, but further randomized controlled trials should be performed to confirm the findings.

Ketamine in Acute Brain Injury: Current Opinion Following Cerebral Circulation and Electrical Activity

The use of ketamine in patients with TBI has often been argued due to its possible deleterious effects on cerebral circulation and perfusion. Early studies suggested that ketamine could increase intracranial pressure, decreasing cerebral perfusion pressure and thereby reducing oxygen supply to the damaged cerebral cortex. Some recent studies have refuted these conclusions relating to the role of ketamine, especially in patients with TBI, showing that ketamine should be the first-choice drug in this type of patient at induction. Our narrative review collects evidence on ketamine’s use in patients with TBI. Databases were examined for studies in which ketamine had been used in acute traumatic brain injury (TBI). The outcomes considered in this narrative review were: mortality of patients with TBI; impact on intracranial pressure and cerebral perfusion pressure; blood pressure and heart rate values; depolarization rate; and preserved neurological functions. 11 recent studies passed inclusion and exclusion criteria and were included in this review. Despite all the benefits reported in the literature, the use of ketamine in patients with brain injury still appears to be limited. A slight increase in intracranial pressure was found in only two studies, while two smaller studies showed a reduction in intracranial pressure after ketamine administration. There was no evidence of harm from the ketamine’s use in patients with TBI.

Efficacy and safety of ketamine in mechanically ventilated intensive care unit patients: a scoping review

Objectives: Mechanically ventilated patients account for about one-third of all admissions to the intensive care unit (ICU). Ketamine has been conditionally recommended to aid with analgesia in such patients, with low quality of evidence available to support this recommendation. We aimed to perform a narrative scoping review of the current knowledge of the use of ketamine, with a specific focus on mechanically ventilated ICU patients. Methods: We searched MEDLINE and EMBASE for relevant articles. Bibliographies of retrieved articles were examined for references of potential relevance. We included studies that described the use of ketamine for postoperative and emergency department management of pain and in the critically unwell, mechanically ventilated population. Results: There are few randomised controlled trials evaluating ketamine's utility in the ICU. The evidence is predominantly retrospective and observational in nature and the results are heterogeneous. Available evidence is summarised in a descriptive manner, with a division made between high dose and low dose ketamine. Ketamine's pharmacology and use as an analgesic agent outside of the ICU is briefly discussed, followed by evidence for use in the ICU setting, with particular emphasis on analgesia, sedation and intubation. Finally, data on adverse effects including delirium, coma, haemodynamic adverse effects, raised intracranial pressure, hypersalivation and laryngospasm are presented. Conclusions: Ketamine is used in mechanically ventilated ICU patients with several potentially positive clinical effects. However, it has a significant side effect profile, which may limit its use in these patients. The role of low dose ketamine infusion in mechanically ventilated ICU patients is not well studied and requires investigation in high quality, prospective randomised trials.

Impact of Ketamine on Analgosedative Consumption in Critically Ill Patients: A Systematic Review and Meta-Analysis

Objective:

The aim of this study was to synthesize evidence available on continuous infusion ketamine versus nonketamine regimens for analgosedation in critically ill patients.

Data sources

A search of MEDLINE, EMBASE, CINAHL, CDSR, and ClinicalTrials.gov was performed from database establishment to November 2021 using the following search terms: critical care, ICU, ketamine, sedation, and anesthesia. All studies included the primary outcome of interest: daily opioid and/or sedative consumption.

Study selection and data extraction

Relevant human studies were considered. Randomized controlled trials (RCT), quasi-experimental studies, and observational cohort studies were eligible. Two reviewers independently screened articles, extracted data, and appraised studies using the Cochrane RoB and ROBINS-I tools.

Data synthesis

A total of 13 RCTs, 5 retrospective, and 1 prospective cohort study were included (2255 participants). The primary analysis of six RCTs demonstrated reduced opioid consumption with ketamine regimens (n = 494 participants, −13.19 µg kg⁻¹ h⁻¹ morphine equivalents, 95% CI −22.10 to −4.28, P = 0.004). No significant difference was observed in sedative consumption, duration of mechanical ventilation (MV), ICU or hospital length of stay (LOS), intracranial pressure, and mortality. Small sample size of studies may have limited ability to detect true differences between groups.

Relevance to patient care and clinical practice

This meta-analysis examining ketamine use in critically ill patients is the first restricting analysis to RCTs and includes up-to-date publication of trials. Findings may guide clinicians in consideration and dosing of ketamine for multimodal analgosedation.

Conclusion

Results suggest ketamine as an adjunct analgosedative has the potential to reduce opioid exposure in postoperative and MV patients in the ICU. More RCTs are required before recommending routine use of ketamine in select populations.

Analgesia in the Neurosurgical Intensive Care Unit

Acute pain in neurosurgical patients is an important issue. Opioids are the most used for pain treatment in the neurosurgical ICU. Potential side effects of opioid use such as oversedation, respiratory depression, hypercapnia, worsening intracranial pressure, nausea, and vomiting may be problems and could interfere with neurologic assessment. Consequently, reducing opioids and use of non-opioid analgesics and adjuvants (N-methyl-D-aspartate antagonists, α2 -adrenergic agonists, anticonvulsants, corticosteroids), as well as non-pharmacological therapies were introduced as a part of a multimodal regimen. Local and regional anesthesia is effective in opioid reduction during the early postoperative period. Among non-opioid agents, acetaminophen and non-steroidal anti-inflammatory drugs are used frequently. Adverse events associated with opioid use in neurosurgical patients are discussed. Larger controlled studies are needed to find optimal pain management tailored to neurologically impaired neurosurgical patients.

Low-dose fentanyl reduces pain perception, muscle sympathetic nerve activity responses, and blood pressure responses during the cold pressor test

Our knowledge about how low-dose (analgesic) fentanyl affects autonomic cardiovascular regulation is primarily limited to animal experiments. Notably, it is unknown if low-dose fentanyl influences human autonomic cardiovascular responses during painful stimuli in humans. Therefore, we tested the hypothesis that low-dose fentanyl reduces perceived pain and subsequent sympathetic and cardiovascular responses in humans during an experimental noxious stimulus. Twenty-three adults (10 females/13 males; 27 ± 7 yr; 26 ± 3 kg·m^-2, means ± SD) completed this randomized, crossover, placebo-controlled trial during two laboratory visits. During each visit, participants completed a cold pressor test (CPT; hand in ∼0.4°C ice bath for 2 min) before and 5 min after drug/placebo administration (75 μg fentanyl or saline). We compared pain perception (100-mm visual analog scale), muscle sympathetic nerve activity (MSNA; microneurography, 11 paired recordings), and beat-to-beat blood pressure (BP; photoplethysmography) between trials (at both pre- and postdrug/placebo timepoints) using paired, two-tailed t tests. Before drug/placebo administration, perceived pain (P = 0.8287), ΔMSNA burst frequency (P = 0.7587), and Δmean BP (P = 0.8649) during the CPT were not different between trials. After the drug/placebo administration, fentanyl attenuated perceived pain (36 vs. 66 mm, P < 0.0001), ΔMSNA burst frequency (9 vs. 17 bursts/min, P = 0.0054), and Δmean BP (7 vs. 13 mmHg, P = 0.0174) during the CPT compared with placebo. Fentanyl-induced reductions in pain perception and Δmean BP were moderately related (r = 0.40, P = 0.0641). These data provide valuable information regarding how low-dose fentanyl reduces autonomic cardiovascular responses during an experimental painful stimulus.

Ketamine for critically ill patients with severe acute brain injury: Protocol for a systematic review with meta-analysis and Trial Sequential Analysis of randomised clinical trials

INTRODUCTION

Intensive care for patients with severe acute brain injury aims both to treat the immediate consequences of the injury and to prevent and treat secondary brain injury to ensure a good functional outcome. Sedation may be used to facilitate mechanical ventilation, for treating agitation, and for controlling intracranial pressure. Ketamine is an N-methyl-D-aspartate receptor antagonist with sedative, analgesic, and potentially neuroprotective properties. We describe a protocol for a systematic review of randomised clinical trials assessing the beneficial and harmful effects of ketamine for patients with severe acute brain injury.

METHODS AND ANALYSIS

We will systematically search international databases for randomised clinical trials, including CENTRAL, MEDLINE, Embase, and trial registries. Two authors will independently review and select trials for inclusion, and extract data. We will compare ketamine by any regimen versus placebo, no intervention, or other sedatives or analgesics for patients with severe acute brain injury. The primary outcomes will be functional outcome at maximal follow up, quality of life, and serious adverse events. We will also assess secondary and exploratory outcomes. The extracted data will be analysed using Review Manager and Trials Sequential Analysis. Evidence certainty will be graded using GRADE.

ETHICS AND DISSEMINATION

The results of the systematic review will be disseminated through peer-reviewed publication. With the review, we hope to inform future randomised clinical trials and improve clinical practice.

PROSPERO NO

CRD42021210447.

Ketamine as an Anesthetic for Patients with Acute Brain Injury: A Systematic Review

For years, the use of ketamine as an anesthetic to patients suffering from acute brain injury has been debated because of its possible deleterious effects on the cerebral circulation and thus on the cerebral perfusion. Early studies suggested that ketamine could increase the intracranial pressure thus lowering the cerebral perfusion and hence reduce the oxygen supply to the injured brain. However, more recent studies are less conclusive and might even indicate that patients with acute brain injury could benefit from ketamine sedation. This systematic review summarizes the evidence regarding the use of ketamine in patients suffering from traumatic brain injury. Databases were searched for studies using ketamine in acute brain injury. Outcomes of interest were mortality, intracranial pressure, cerebral perfusion pressure, blood pressure, heart rate, spreading depolarizations, and neurological function. In total 11 studies were included. The overall level of evidence concerning the use of ketamine in brain injury is low. Only two studies found a small increase in intracranial pressure, while two small studies found decreased levels of intracranial pressure following ketamine administration. We found no evidence of harm during ketamine use in patients suffering from acute brain injury.

Brain Herniation and Intracranial Hypertension

This article introduces the basic concepts of intracranial physiology and pressure dynamics. It also includes discussion of signs and symptoms and examination and radiographic findings of patients with acute cerebral herniation as a result of increased as well as decreased intracranial pressure. Current best practices regarding medical and surgical treatments and approaches to management of intracranial hypertension as well as future directions are reviewed. Lastly, there is discussion of some of the implications of critical medical illness (sepsis, liver failure, and renal failure) and treatments thereof on causation or worsening of cerebral edema, intracranial hypertension, and cerebral herniation.

Sedation, Analgesia, and Paralysis in COVID-19 Patients in the Setting of Drug Shortages

The rapid spread of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has led to a global pandemic. The 2019 coronavirus disease (COVID-19) presents with a spectrum of symptoms ranging from mild to critical illness requiring intensive care unit (ICU) admission. Acute respiratory distress syndrome is a major complication in patients with severe COVID-19 disease. Currently, there are no recognized pharmacological therapies for COVID-19. However, a large number of COVID-19 patients require respiratory support, with a high percentage requiring invasive ventilation. The rapid spread of the infection has led to a surge in the rate of hospitalizations and ICU admissions, which created a challenge to public health, research, and medical communities. The high demand for several therapies, including sedatives, analgesics, and paralytics, that are often utilized in the care of COVID-19 patients requiring mechanical ventilation, has created pressure on the supply chain resulting in shortages in these critical medications. This has led clinicians to develop conservation strategies and explore alternative therapies for sedation, analgesia, and paralysis in COVID-19 patients. Several of these alternative approaches have demonstrated acceptable levels of sedation, analgesia, and paralysis in different settings but they are not commonly used in the ICU. Additionally, they have unique pharmaceutical properties, limitations, and adverse effects. This narrative review summarizes the literature on alternative drug therapies for the management of sedation, analgesia, and paralysis in COVID-19 patients. Also, this document serves as a resource for clinicians in current and future respiratory illness pandemics in the setting of drug shortages.

Non-opioid analgesics as adjuvants to opioid for pain management in adult patients in the ICU: A systematic review and meta-analysis

PURPOSE

To identify the impact of non-opioid analgesics as adjuvants to opioid on opioid consumption and its side effects, as well as the analgesic effectiveness in adult patients in the ICU.

METHODS

Only randomized clinical trials using non-opioid analgesics for analgesia in the ICU were included. Pooled analyses with 95% CI were determined.

RESULTS

Twelve studies (mainly surgical and Guillain-Barre syndrome patients) were included. Non-opioid analgesics as adjuvants to opioid were associated with a significant reduction in the consumption of opioids when compared with opioid use alone at Day 1 (MD -15.40; 95% CI -22.41 to -8.39; P < .001) and Day 2 (MD -22.93; 95% CI -27.70 to -18.16; P < .001). Non-opioid analgesics as adjuvants to opioid were associated with a significantly lower incidence of nausea and vomiting when compared with opioid use alone (RR 0.46; 95% CI 0.30 to 0.68; P < .001). Non-opioid analgesics as adjuvants to opioid significantly decreased the pain score at Day 1 (MD -0.68; 95% CI -1.28 to -0.08; P = .03) and Day 2 (MD -1.36; 95% CI -2.47 to -0.24; P = .02).

CONCLUSIONS

Non-opioid analgesics as adjuvants to opioid reduced the consumption and the side effects of opioids in adult surgical and Guillain-Barre syndrome patients in the ICU.

TRIAL REVIEW REGISTRATION

PROSPERO international prospective register of systematic reviews on January 23, 2017, registration number CRD42017055768.

Head Trauma

Head trauma is a common cause of significant morbidity and mortality in dogs and cats. Traumatic brain injury may occur after head trauma. Understanding the pathophysiology of primary and secondary injury after head trauma is essential for management. This article reviews the pathophysiology of head trauma, patient assessment and diagnostics, and treatment recommendations.

Analgosedation of adult patients with elevated intracranial pressure : Survey of current clinical practice in Austria

BACKGROUND

Analgesia and sedation are key items in intensive care. Recently published S3 guidelines specifically address treatment of patients with elevated intracranial pressure.

METHODS

The Austrian Society of Anesthesiology, Resuscitation and Intensive Care Medicine carried out an online survey of neurointensive care units in Austria in order to evaluate the current state of practice in the areas of analgosedation and delirium management in this high-risk patient group.

RESULTS

The response rate was 88%. Induction of anesthesia in patients with elevated intracranial pressure is carried out with propofol/fentanyl/rocuronium in >80% of the intensive care units (ICU), 60% use midazolam, 33.3% use esketamine, 13.3% use barbiturates and 6.7% use etomidate. For maintenance of analgosedation up to 72 h, propofol is used by 80% of the ICUs, followed by remifentanil (46.7%), sufentanil (40%) and fentanyl (6.7%). For long-term sedation, 86.7% of ICUs use midazolam, 73.3% sufentanil and 73.3% esketamine. For sedation periods longer than 7 days, 21.4% of ICUs use propofol. Reasons for discontinuing propofol are signs of rhabdomyolysis (92.9%), green urine, elevated liver enzymes (71.4% each) and elevated triglycerides (57.1%). Muscle relaxants are only used during invasive procedures. Inducing a barbiturate coma is rated as a last resort by 53.3% of respondents. The monitoring methods used are bispectral index (BIS™, 61.5% of ICUs), somatosensory-evoked potentials (SSEP, 53.8%), processed electroencephalography (EEG, 38.5%), intraparenchymal partial pressure of oxygen (pO₂, 38.5%) and microdialysis (23.1%). Sedation and analgesia are scored using the Richmond agitation and sedation score (RASS, 86.7%), sedation agitation scale (SAS, 6.7%) or numeric rating scale (NRS, 50%) and behavioral pain scale (BPS, 42.9%), visual analogue scale (VAS), critical care pain observation tool (CCPOT, each 14.3%) and verbal rating scale (VRS, 7.1%). Delirium monitoring is done using the confusion assessment method for intensive care units (CAM-ICU, 46.2%) and intensive care delirium screening checklist (ICDSC, 7.7%). Of the ICUs 46.2% do not carry out delirium monitoring.

CONCLUSION

We found good general compliance with the recommendations of the current S3 guidelines. Room for improvement exists in monitoring and the use of scores to detect delirium.

Continuous Infusion Antiepileptic Medications for Refractory Status Epilepticus: A Review for Nurses

Status epilepticus requires treatment with emergent initial therapy with a benzodiazepine and urgent control therapy with an additional antiepileptic drug (AED) to terminate clinical and/or electrographic seizure activity. However, nearly one-third of patients will prove refractory to the aforementioned therapies and are prone to a higher degree of neuronal injury, resistance to pharmacotherapy, and death. Current guidelines for refractory status epilepticus (RSE) recommend initiating a continuous intravenous (CIV) anesthetic over bolus dosing with a different AED. Continuous intravenous agents most commonly used for this indication include midazolam, propofol, and pentobarbital, but ketamine is an alternative option. Comparative studies illustrating the optimal agent are lacking, and selection is often based on adverse effect profiles and patient-specific factors. In addition, dosing and titration are largely based on small studies and expert opinion with continuous electroencephalogram monitoring used to guide intensity and duration of treatment. Nonetheless, the doses required to halt seizure activity are likely to produce profound adverse effects that clinicians should anticipate and combat. The purpose of this review was to summarize the available RSE literature focusing on CIV midazolam, pentobarbital, propofol, and ketamine, and to serve as a primer for nurses providing care to these patients.

Ketamine: 50 Years of Modulating the Mind

Ketamine was introduced into clinical practice in the 1960s and continues to be both clinically useful and scientifically fascinating. With considerably diverse molecular targets and neurophysiological properties, ketamine’s effects on the central nervous system remain incompletely understood. Investigators have leveraged the unique characteristics of ketamine to explore the invariant, fundamental mechanisms of anesthetic action. Emerging evidence indicates that ketamine-mediated anesthesia may occur via disruption of corticocortical information transfer in a frontal-to-parietal (“top down”) distribution. This proposed mechanism of general anesthesia has since been demonstrated with anesthetics in other pharmacological classes as well. Ketamine remains invaluable to the fields of anesthesiology and critical care medicine, in large part due to its ability to maintain cardiorespiratory stability while providing effective sedation and analgesia. Furthermore, there may be an emerging role for ketamine in treatment of refractory depression and Post-Traumatic Stress Disorder. In this article, we review the history of ketamine, its pharmacology, putative mechanisms of action and current clinical applications.

Fentanyl and Midazolam Are Ineffective in Reducing Episodic Intracranial Hypertension in Severe Pediatric Traumatic Brain Injury

OBJECTIVE

To evaluate the clinical effectiveness of bolus-dose fentanyl and midazolam to treat episodic intracranial hypertension in children with severe traumatic brain injury.

DESIGN

Retrospective cohort.

SETTING

PICU in a university-affiliated children's hospital level I trauma center.

PATIENTS

Thirty-one children 0-18 years of age with severe traumatic brain injury (Glasgow Coma Scale score of ≤ 8) who received bolus doses of fentanyl and/or midazolam for treatment of episodic intracranial hypertension.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The area under the curve from high-resolution intracranial pressure-time plots was calculated to represent cumulative intracranial hypertension exposure: area under the curve for intracranial pressure above 20 mm Hg (area under the curve-intracranial hypertension) was calculated in 15-minute epochs before and after administration of fentanyl and/or midazolam for the treatment of episodic intracranial hypertension. Our primary outcome measure, the difference between predrug and postdrug administration epochs (Δarea under the curve-intracranial hypertension), was calculated for all occurrences. We examined potential covariates including age, injury severity, mechanism, and time after injury; time after injury correlated with Δarea under the curve-intracranial hypertension. In a mixed-effects model, with patient as a random effect, drug/dose combination as a fixed effect, and time after injury as a covariate, intracranial hypertension increased after administration of fentanyl and/or midazolam (overall aggregate mean Δarea under the curve-intracranial hypertension = +17 mm Hg × min, 95% CI, 0-34 mm Hg × min; p = 0.04). The mean Δarea under the curve-intracranial hypertension increased significantly after administration of high-dose fentanyl (p = 0.02), low-dose midazolam (p = 0.006), and high-dose fentanyl plus low-dose midazolam (0.007). Secondary analysis using age-dependent thresholds showed no significant impact on cerebral perfusion pressure deficit (mean Δarea under the curve-cerebral perfusion pressure).

CONCLUSIONS

Bolus dosing of fentanyl and midazolam fails to reduce the intracranial hypertension burden when administered for episodic intracranial hypertension. Paradoxically, we observed an overall increase in intracranial hypertension burden following drug administration, even after accounting for within-subject effects and time after injury. Future work is needed to confirm these findings in a prospective study design.

Ketamine for analgosedation in critically ill patients

PURPOSE

The purpose of this narrative review is to provide practical and useful guidance for clinicians considering the use of intravenous ketamine for its analgosedative properties in adult, critically ill patients.

METHODS

MEDLINE was searched from inception until January 2016. Articles related to the pharmacological properties of ketamine were retrieved. Information pertaining to pharmacology, pharmacokinetics, dosing regimens, adverse effects, and outcomes was obtained from relevant studies.

RESULTS

Although the primary mechanism for ketamine's pharmacological effects is N-methyl-d-aspartate blockade, there are several potential mechanisms of action. It has a very large volume of distribution due to its lipophilicity, which can lead to drug accumulation with sustained infusions. Ketamine has several advantages compared with conventional sedatives such as preserving pharyngeal and laryngeal protective reflexes, lowering airway resistance, increasing lung compliance, and being less likely to produce respiratory depression. It causes sympathetic stimulation, which is also unlike other sedatives and analgesics. There are psychotomimetic effects, which are a concern in terms of delirium. Dosing and monitoring recommendations are provided.

CONCLUSIONS

Ketamine has a unique pharmacological profile compared with more traditional agents such as opioids, which makes it an appealing alternative agent for analgosedation in the intensive care unit setting.

The Future of Intensive Care Unit Sedation: A Report of Continuous Infusion Ketamine as an Alternative Sedative Agent

This report describes a patient case utilizing a nontraditional sedative, continuous infusion ketamine, as an alternative agent for intensive care unit (ICU) sedation. A 27-year-old female presented for neurosurgical management of a coup contrecoup injury, left temporal fracture, epidural hemorrhage (EDH), and temporal contusion leading to sustained mechanical ventilation. The patient experienced profound agitation during mechanical ventilation and developed adverse effects with all traditional sedatives: benzodiazepines, dexmedetomidine, opioids, and propofol. Ketamine was titrated to effect and eliminated the need for other agents. This led to successful ventilator weaning, extubation, and transition of care. Given the unique side effect profile of ketamine, it is imperative that information is disseminated on potential utilization of this agent. More information is needed regarding dosing, monitoring, and long-term effects of utilizing ketamine as a continuous ICU sedative, but given the analgesia, anesthesia, and cardiopulmonary stability, future utilization of this medication for this indication seems promising.

Ketamine for Analgosedation in the Intensive Care Unit: A Systematic Review

OBJECTIVE

To evaluate the evidence for the use of intravenous ketamine for analgosedation in the intensive care unit.

METHODS

MEDLINE and EMBASE were queried from inception until July 2015. Search terms used included ketamine, intensive care, and critical care. The search retrieved 584 articles to be screened for inclusion. The intent was to include randomized controlled studies using sustained intravenous infusions (>24 hours) of ketamine in the critically ill patients.

RESULTS

One trial evaluated opioid consumption as an outcome in postoperative critically ill patients who were randomized to ketamine or saline infusions. The mean cumulative morphine consumption at 48 hours was significantly lower in the ketamine group (58 ± 35 mg) compared to the morphine-only group (80 ± 37 mg; P < .05). Other trials showed the potential safety of ketamine in terms of cerebral hemodynamics in patients with traumatic brain injury, improved gastrointestinal motility, and decreased vasopressor requirements. The observational study and case reports suggest that ketamine is safe and effective and may have a role in patients who are refractory to other therapies.

CONCLUSION

Ketamine use may decrease analgesic consumption in the intensive care unit. Additional trials are needed to further delineate the role of ketamine for analgosedation.

Remifentanil, ketamine, and fospropofol: a review of alterative continuous infusion agents for sedation in the critically ill

Sedation and analgesia are integral aspects in the care of critically ill patients admitted to the intensive care unit. In recent years, many of the commonly used sedative agents in the United States have experienced manufacturing and sterility issues leading to decreased availability. In addition, current practice has shifted to providing lighter levels of sedation as clinicians have gained a better understanding of the consequences of prolonged deep sedation. Benzodiazepines have fallen out of favor due to findings including increased delirium and duration of mechanical ventilation. Alterations in end-organ function in critically ill patients may also lead to varied responses to commonly used sedatives. With numerous factors impacting choice of sedation in the intensive care unit, fospropofol, ketamine, and remifentanil have been considered potential alternatives to standard therapy. The purpose of this review was to discuss strategies for the safe and effective use of fospropofol, ketamine, and remifentanil for continuous intravenous sedation in critically ill patients.

The effect of ketamine on intracranial and cerebral perfusion pressure and health outcomes: a systematic review

STUDY OBJECTIVE

We synthesize the available evidence on the effect of ketamine on intracranial and cerebral perfusion pressures, neurologic outcomes, ICU length of stay, and mortality.

METHODS

We developed a systematic search strategy and applied it to 6 electronic reference databases. We completed a gray literature search and searched medical journals as well as the bibliographies of relevant articles. We included randomized and nonrandomized prospective studies that compared the effect of ketamine with another intravenous sedative in intubated patients and reported at least 1 outcome of interest. Two authors independently performed title, abstract, and full-text reviews, and abstracted data from all studies, using standardized forms. Data from randomized controlled trials and prospective studies were synthesized in a qualitative manner because the study designs, patient populations, reported outcomes, and follow-up periods were heterogeneous. We used the Jadad score and Cochrane Risk of Bias tool to assess study quality.

RESULTS

We retrieved 4,896 titles, of which 10 studies met our inclusion criteria, reporting data on 953 patients. One study was deemed at low risk of bias in all quality assessment domains. All others were at high risk in at least 1 domain. Two of 8 studies reported small reductions in intracranial pressure within 10 minutes of ketamine administration, and 2 studies reported an increase. None of the studies reported significant differences in cerebral perfusion pressure, neurologic outcomes, ICU length of stay, or mortality.

CONCLUSION

According to the available literature, the use of ketamine in critically ill patients does not appear to adversely affect patient outcomes.

Ketamine does not increase intracranial pressure compared with opioids: meta-analysis of randomized controlled trials

BACKGROUND

Ketamine is traditionally avoided in sedation management of patients with risk of intracranial hypertension. However, results from many clinical trials contradict this concern. We critically analyzed the published data of the effects of ketamine on intracranial pressure (ICP) and other cerebral hemodynamics to determine whether ketamine was safe for patients with hemodynamic instability and brain injuries.

METHODS

We systematically searched the online databases of PubMed, Medline, Embase, Current Controlled Trials, and Cochrane Central (last search performed on January 15, 2014). Trial characteristics and outcomes were independently extracted by two assessors (Xin Wang, Xibing Ding). For continuous data, mean differences (MD) were formulated. If the P value of the chi-square test was >0.10 or I(2) <50%, a fixed-effects model was used; otherwise, the random effects model was adopted.

RESULTS

Five trials (n = 198) met the inclusion criteria. Using ICP levels within the first 24 h of ketamine administration as the main outcome, the use of ketamine leads to the same ICP levels as opioids [MD = 1.94; 95% confidence interval (95% CI), -2.35, 6.23; P = 0.38]. There were no significant differences in mean arterial pressure values between the two groups (MD = 0.99; 95% CI, -2.24, 4.22; P = 0.55). Ketamine administration was also comparable with opioids in the maintenance of cerebral perfusion pressure (MD = -1.07; 95% CI, -7.95, 5.8; P = 0.76).

CONCLUSIONS

The results of this study suggest that ketamine does not increase ICP compared with opioids. Ketamine provides good maintenance of hemodynamic status. Clinical application of ketamine should not be discouraged on the basis of ICP-related concerns.

Palliative care in the ICU: relief of pain, dyspnea, and thirst--a report from the IPAL-ICU Advisory Board

PURPOSE

Pain, dyspnea, and thirst are three of the most prevalent, intense, and distressing symptoms of intensive care unit (ICU) patients. In this report, the interdisciplinary Advisory Board of the Improving Palliative Care in the ICU (IPAL-ICU) Project brings together expertise in both critical care and palliative care along with current information to address challenges in assessment and management.

METHODS

We conducted a comprehensive review of literature focusing on intensive care and palliative care research related to palliation of pain, dyspnea, and thirst.

RESULTS

Evidence-based methods to assess pain are the enlarged 0-10 Numeric Rating Scale (NRS) for ICU patients able to self-report and the Critical Care Pain Observation Tool or Behavior Pain Scale for patients who cannot report symptoms verbally or non-verbally. The Respiratory Distress Observation Scale is the only known behavioral scale for assessment of dyspnea, and thirst is evaluated by patient self-report using an 0-10 NRS. Opioids remain the mainstay for pain management, and all available intravenous opioids, when titrated to similar pain intensity end points, are equally effective. Dyspnea is treated (with or without invasive or noninvasive mechanical ventilation) by optimizing the underlying etiological condition, patient positioning and, sometimes, supplemental oxygen. Several oral interventions are recommended to alleviate thirst. Systematized improvement efforts addressing symptom management and assessment can be implemented in ICUs.

CONCLUSIONS

Relief of symptom distress is a key component of critical care for all ICU patients, regardless of condition or prognosis. Evidence-based approaches for assessment and treatment together with well-designed work systems can help ensure comfort and related favorable outcomes for the critically ill.

A standardized rapid sequence intubation protocol facilitates airway management in critically injured patients

BACKGROUND

In the emergency department (ED) of a teaching hospital, rapid sequence intubation (RSI) is performed by physicians with a wide range of experience. A variety of medications have been used for RSI, with potential for inadequate or excessive dosing as well as complications including hypotension and the need for redosing. We hypothesized that the use of a standardized RSI medication protocol has facilitated endotracheal intubation requiring less medication redosing and less medication-related hypotension.

METHODS

An RSI medication protocol (ketamine 2 mg/kg intravenously administered and rocuronium 1 mg/kg intravenously administered, or succinylcholine 1.5 mg/kg intravenously administered) was implemented for all trauma patients undergoing ED intubation at a Level I trauma center. We retrospectively reviewed patients for the 1-year period before (PRE) and after (KET) the protocol was instituted. Data collected included age, sex, Injury Severity Score (ISS), Abbreviated Injury Scale (AIS) score of the head/face, AIS score of the chest, RSI drugs, need for redosing, time to intubation, indication for RSI, and number of RSI attempts.

RESULTS

During the study period, 439 patients met inclusion criteria; 266 without protocol (PRE) and 173 with protocol (KET). Patients were severely injured with a mean ISS of 24 and median AIS score of the head/face of 3. Dosing in the KET group was appropriate with a mean dose of 1.9-mg/kg ketamine administered. Compliance after KET introduction approached 90%. Fifteen patients in the PRE group required redosing of medication versus three in the KET group (p < 0.05, χ). For patients younger than 14 years, (26 in PRE and 10 in KET), 2 patients in the PRE group required redosing and none in the KET group (not significant). In all patients, mean time from drug administration to intubation decreased from 4 minutes to 3 minutes.

CONCLUSION

A standardized medication protocol simplifies RSI and allows efficient airway management of critically injured trauma patients in the ED of a teaching hospital. Incorporation of ketamine avoids potential complications of other commonly used RSI medications.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Brain damages in ketamine addicts as revealed by magnetic resonance imaging

Ketamine, a known antagonist of N-methyl-D-aspartic (NMDA) glutamate receptors, had been used as an anesthetic particularly for pediatric or for cardiac patients. Unfortunately, ketamine has become an abusive drug in many parts of the world while chronic and prolonged usage led to damages of many organs including the brain. However, no studies on possible damages in the brains induced by chronic ketamine abuse have been documented in the human via neuroimaging. This paper described for the first time via employing magnetic resonance imaging (MRI) the changes in ketamine addicts of 0.5–12 years and illustrated the possible brain regions susceptible to ketamine abuse. Twenty-one ketamine addicts were recruited and the results showed that the lesions in the brains of ketamine addicts were located in many regions which appeared 2–4 years after ketamine addiction. Cortical atrophy was usually evident in the frontal, parietal or occipital cortices of addicts. Such study confirmed that many brain regions in the human were susceptible to chronic ketamine injury and presented a diffuse effect of ketamine on the brain which might differ from other central nervous system (CNS) drugs, such as cocaine, heroin, and methamphetamine.

Rapid sequence intubation medication therapies: a review in light of recent drug shortages

Rapid sequence intubation is a stepwise process developed to assist health care providers in placing emergent artificial airways for patients requiring assisted ventilation. This practice includes routine administration of sedative and neuromuscular blocking agent (NMBA) medications for patient comfort during endotracheal tube placement. Members of the multidisciplinary team should be well educated about the various medications used during this process to ensure safe medication practices in an emergent situation. Recent drug shortages have forced many health care professionals to use alternative medications with which they are less familiar. The intent of this review is to familiarize health care providers with the pharmacology and adverse effect profiles of alternative sedative and NMBA medications used in emergent airway placement in light of recent drug shortages.

Management of intracerebral pressure in the neurosciences critical care unit

Management of intracranial pressure in neurocritical care remains a potentially valuable target for improvements in therapy and patient outcomes. Surrogate markers of increased intracranial pressure, invasive monitors, and standard therapy, as well as promising new approaches to improve cerebral compliance are discussed, and a current review of the literature addressing this metric in neuroscience critical care is provided.

The emerging use of ketamine for anesthesia and sedation in traumatic brain injuries

Traditionally, the use of ketamine for patients with traumatic brain injuries is contraindicated due to the concern of increasing intracranial pressure (ICP). These concerns, however, originated from early studies and case reports that were inadequately controlled and designed. Recently, the concern of using ketamine in these patients has been challenged by a number of published studies demonstrating that the use of ketamine was safe in these patients. This article reviews the current literature in regards to using ketamine in patients with traumatic brain injuries in different clinical settings associated with anesthesia, as well as reviews the potential mechanisms underlying the neuroprotective effects of ketamine. Studies examining the use of ketamine for induction, maintenance, and sedation in patients with TBI have had promising results. The use of ketamine in a controlled ventilation setting and in combination with other sedative agents has demonstrated no increase in ICP. The role of ketamine as a neuroprotective agent in humans remains inconclusive and adequately powered; randomized controlled trials performed in patients undergoing surgery for traumatic brain injury are necessary.

Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit

OBJECTIVE

To revise the "Clinical Practice Guidelines for the Sustained Use of Sedatives and Analgesics in the Critically Ill Adult" published in Critical Care Medicine in 2002.

METHODS

The American College of Critical Care Medicine assembled a 20-person, multidisciplinary, multi-institutional task force with expertise in guideline development, pain, agitation and sedation, delirium management, and associated outcomes in adult critically ill patients. The task force, divided into four subcommittees, collaborated over 6 yr in person, via teleconferences, and via electronic communication. Subcommittees were responsible for developing relevant clinical questions, using the Grading of Recommendations Assessment, Development and Evaluation method (http://www.gradeworkinggroup.org) to review, evaluate, and summarize the literature, and to develop clinical statements (descriptive) and recommendations (actionable). With the help of a professional librarian and Refworks database software, they developed a Web-based electronic database of over 19,000 references extracted from eight clinical search engines, related to pain and analgesia, agitation and sedation, delirium, and related clinical outcomes in adult ICU patients. The group also used psychometric analyses to evaluate and compare pain, agitation/sedation, and delirium assessment tools. All task force members were allowed to review the literature supporting each statement and recommendation and provided feedback to the subcommittees. Group consensus was achieved for all statements and recommendations using the nominal group technique and the modified Delphi method, with anonymous voting by all task force members using E-Survey (http://www.esurvey.com). All voting was completed in December 2010. Relevant studies published after this date and prior to publication of these guidelines were referenced in the text. The quality of evidence for each statement and recommendation was ranked as high (A), moderate (B), or low/very low (C). The strength of recommendations was ranked as strong (1) or weak (2), and either in favor of (+) or against (-) an intervention. A strong recommendation (either for or against) indicated that the intervention's desirable effects either clearly outweighed its undesirable effects (risks, burdens, and costs) or it did not. For all strong recommendations, the phrase "We recommend …" is used throughout. A weak recommendation, either for or against an intervention, indicated that the trade-off between desirable and undesirable effects was less clear. For all weak recommendations, the phrase "We suggest …" is used throughout. In the absence of sufficient evidence, or when group consensus could not be achieved, no recommendation (0) was made. Consensus based on expert opinion was not used as a substitute for a lack of evidence. A consistent method for addressing potential conflict of interest was followed if task force members were coauthors of related research. The development of this guideline was independent of any industry funding.

CONCLUSION

These guidelines provide a roadmap for developing integrated, evidence-based, and patient-centered protocols for preventing and treating pain, agitation, and delirium in critically ill patients.

Pain management in the ICU

Pain management in the intensive care unit (ICU) is a complex process. Both the experience of pain as well as its treatment can have consequences relating to the overall outcome of the patient. Further, lack of the ability of many patients in the ICU to communicate their distress makes it even more critical for the ICU practitioner to understand the typical causes of pain in this setting and the applicability of many pain management regimens.

Ketamine in Adult Emergency Medicine: Controversies and Recent Advances

Objective:

To review the evidence for the use of ketamine in adult emergency medicine for procedural sedation and analgesia (PSA) and rapid sequence intubation (RSI), as well as to focus on the issues of recovery agitation, combination with propofol for PSA, and the use of ketamine as an induction agent in patients with acute head injury in need of definitive airway management.

Data Sources:

PubMed (1949-July 2011), EMBASE (1980-July 2011), Google Scholar (to July 2011), International Pharmaceutical Abstracts (1964-July 2011), and Cochrane databases were searched independently. A manual search of references was also performed,

Study Selection:

English-language, full reports of experimental and observational studies evaluating ketamine in adults undergoing PSA and RSI in the emergency department (ED) were Included if they reported efficacy or safety outcomes.

Data Extraction:

Two reviewers independently assessed each article for inclusion, data extraction, and study limitations.

Data Synthesis:

Six studies that used ketamine for PSA were included. The majority reported adequate sedation with high patient satisfaction and lack of pain and procedural recall. There is no evidence to support the superiority of a combination of ketamine and propofol compared to propofol alone for PSA in adults. Recovery agitation is common but can be minimized with premedication with midazolam (number needed to treat 6). Two studies were identified that evaluated the role of ketamine for induction during RSI in the ED, Although ketamine is not a first-line agent for RSI, it is an alternative and may be used as an induction agent in patients requiring endotracheal intubation.

Conclusions:

Ketamine is an effective agent in adults undergoing PSA and RSI in the ED. The best available evidence provides sufficient confidence to consider use of this agent in the ED.

Reduced brain tissue oxygen in traumatic brain injury: are most commonly used interventions successful?

BACKGROUND

Brain tissue oxygenation (PbtO2)-guided management facilitates treatment of reduced PbtO2 episodes potentially conferring survival and outcome advantages in severe traumatic brain injury (TBI). To date, the nature and effectiveness of commonly used interventions in correcting compromised PbtO2 in TBI remains unclear. We sought to identify the most common interventions used in episodes of compromised PbtO2 and to analyze which were effective.

METHODS

A retrospective 7-year review of consecutive severe TBI patients with a PbtO2 monitor was conducted in a Level I trauma center's intensive care unit or neurosurgical registry. Episodes of compromised PbtO2 (defined as <20 mm Hg for 0.25-4 hours) were identified, and clinical interventions conducted during these episodes were analyzed. Response to treatment was gauged on how rapidly (ΔT) PbtO2 normalized (>20 mm Hg) and how great the PbtO2 increase was (ΔPbtO2). Intracranial pressure (ΔICP) and cerebral perfusion pressure (ΔCPP) also were examined for these episodes.

RESULTS

Six hundred twenty-five episodes of reduced PbtO2 were identified in 92 patients. Patient characteristics were: age 41.2 years, 77.2% men, and Injury Severity Score and head or neck Abbreviated Injury Scale score of 34.0 ± 9.2 and 4.9 ± 0.4, respectively. Five interventions: narcotics or sedation, pressors, repositioning, FIO2/PEEP increases, and combined sedation or narcotics + pressors were the most commonly used strategies. Increasing the number of interventions resulted in worsening the time to PbtO2 correction. Triple combinations resulted in the lowest ΔICP and dual combinations in the highest ΔCPP (p < 0.05).

CONCLUSION

Clinicians use a limited number of interventions when correcting compromised PbtO2. Using strategies employing many interventions administered closely together may be less effective in correcting PbO2, ICP, and CPP deficits. Some PbtO2 deficits may be self-limited.