Safety and feasibility of continuous infusion of remifentanil in the neurosurgical intensive care unit

Headache management in traumatic brain injury

Traumatic brain injury (TBI) is estimated to rank as the third most important disease burden worldwide. About 60% of the survivors develop chronic headaches and visual symptoms, and the long-term management of headaches in these patients is controversial. Importantly, the care pathway of most patients is fragmented, complicating conclusive headache management. Here we review the epidemiology and aetiology of post traumatic headaches (PTH), discuss the diagnostic work up and summarise the acute and long-term management.

Effects of an Early Intensive Blood Pressure-lowering Strategy Using Remifentanil and Dexmedetomidine in Patients with Spontaneous Intracerebral Hemorrhage: A Multicenter, Prospective, Superiority, Randomized Controlled Trial

BACKGROUND

Although it has been established that elevated blood pressure and its variability worsen outcomes in spontaneous intracerebral hemorrhage, antihypertensives use during the acute phase still lacks robust evidence. A blood pressure-lowering regimen using remifentanil and dexmedetomidine might be a reasonable therapeutic option given their analgesic and antisympathetic effects. The objective of this superiority trial was to validate the efficacy and safety of this blood pressure-lowering strategy that uses remifentanil and dexmedetomidine in patients with acute intracerebral hemorrhage.

METHODS

In this multicenter, prospective, single-blinded, superiority randomized controlled trial, patients with intracerebral hemorrhage and systolic blood pressure (SBP) 150 mmHg or greater were randomly allocated to the intervention group (a preset protocol with a standard guideline management using remifentanil and dexmedetomidine) or the control group (standard guideline-based management) to receive blood pressure-lowering treatment. The primary outcome was the SBP control rate (less than 140 mmHg) at 1 h posttreatment initiation. Secondary outcomes included blood pressure variability, neurologic function, and clinical outcomes.

RESULTS

A total of 338 patients were allocated to the intervention (n = 167) or control group (n = 171). The SBP control rate at 1 h posttreatment initiation in the intervention group was higher than that in controls (101 of 161, 62.7% vs. 66 of 166, 39.8%; difference, 23.2%; 95% CI, 12.4 to 34.1%; P < 0.001). Analysis of secondary outcomes indicated that patients in the intervention group could effectively reduce agitation while achieving lighter sedation, but no improvement in clinical outcomes was observed. Regarding safety, the incidence of bradycardia and respiratory depression was higher in the intervention group.

CONCLUSIONS

Among intracerebral hemorrhage patients with a SBP 150 mmHg or greater, a preset protocol using a remifentanil and dexmedetomidine-based standard guideline management significantly increased the SBP control rate at 1 h posttreatment compared with the standard guideline-based management.

EDITOR’S PERSPECTIVE

Echinochrome pigment extracted from sea urchin suppress the bacterial activity, inflammation, nociception, and oxidative stress resulted in the inhibition of renal injury in septic rats

The current study aimed to evaluate the antibacterial, anti-inflammatory, analgesic, and renoprotective effects of echinochrome pigment extracted from sea urchin. The disk diffusion method was used for the antibacterial activity of echinochrome against four different bacterial strains; Salmonella typhimurium, Pseudomonas aeroginosa, Staphylococcus aureus, and Listeria monocytogenes. While, acetic acid-induced writhing, formalin-induced licking, and hot plate latency assays evaluate the analgesic activity. The biochemical and oxidative stress markers of kidneys, as well as the histopathological examination, were measured to evaluate the renoprotective activity of echinochrome for cecal ligation and puncture-induced renal injury in rats. Echinochrome pigment exhibited in vitro antibacterial activity against all aforementioned bacterial species besides a powerful anti-inflammatory impact in vitro by the effective stabilization of the RBCs membrane and in vivo by decrease levels of serum IL6 and TNF-α. What's more, echinochrome showed a notable analgesic efficacy as well as an enhancement of the kidney's biochemical markers, oxidative stress status, and histopathological screening. Ech attenuated cecal ligation and puncture-induced renal injury by improving renal biomarkers, suppressing reactive oxygen species propagation as well as its antibacterial, anti-inflammatory, and anti-nociceptive activities. PRACTICAL APPLICATIONS: Sea urchins are rich in pharmacologically important quinone pigments, specifically echinochrome. The current study aimed to evaluate the role of echinochrome as a renal protective remedy in sepsis and clarify its biological activities. Echinochrome exhibited antibacterial activity in vitro against Salmonella typhimurium, Pseudomonas aeroginosa, Staphylococcus aureus, and Listeria monocytogenes. Our results revealed that echinochrome protects the kidney against damage caused by sepsis in rats. Echinochrome can use in the treatment of sepsis as an antibacterial, anti-inflammatory, and antioxidant agent.

Management of Elevated Intracranial Pressure

Elevated intracranial pressure (ICP) is a primary cause of morbidity and mortality for many neurologic disorders. The relationship between ICP and brain volume is influenced by autoregulatory processes that can become dysfunctional. As a result, neurologic damage can occur by systemic and intracranial insults such as ischemia and excitatory amino acids. Therefore, survival is dependent on optimizing ICP and cerebral perfusion pressure. Treatment of intracranial hypertension requires intensive monitoring and aggressive therapy. Intracranial pressure monitoring techniques such as intraventricular catheters are useful for determining ICP elevations before changes in vital signs and neurologic status. Therapeutic modalities, generally aimed at reducing cerebral blood volume, brain tissue, and cerebrospinal fluid (CSF) volume, include nonpharmacologic (CSF removal, controlled hyperventilation, and elevating the patient’s head) and pharmacologic management. Mannitol and sedation are first-line agents used to lower ICP. Barbiturate coma may be beneficial in patients with elevated ICP refractory to conventional treatment. The use of prophylactic antiseizure therapy and optimal nutrition prevents significant complication. Currently, investigations are directed at discovering useful neuroprotective agents that prevent secondary neurologic injury.

Comparison of an Intraoperative Infusion of Dexmedetomidine, Fentanyl, and Remifentanil on Perioperative Hemodynamics, Sedation Quality, and Postoperative Pain Control

We aimed to compare fentanyl, remifentanil and dexmedetomidine with respect to hemodynamic stability, postoperative pain control and achievement of sedation at the postanesthetic care unit (PACU). In this randomized double-blind study, 90 consecutive total laparoscopic hysterectomy patients scheduled for elective surgery were randomly assigned to receive fentanyl (1.0 μg/kg) over 1 minute followed by a 0.4 μg/kg/hr infusion (FK group, n = 30), or remifentanil (1.0 μg/kg) over 1 minute followed by a 0.08 μg/kg/min infusion (RK group, n = 30), or dexmedetomidine (1 μg/kg) over 10 minutes followed by a 0.5 μg/kg/hr infusion (DK group, n = 30) initiating at the end of main procedures of the operation to the time in the PACU. A single dose of intravenous ketorolac (30 mg) was given to all patients at the end of surgery. We respectively evaluated the pain VAS scores, the modified OAA/S scores, the BIS, the vital signs and the perioperative side effects to compare the efficacy of fentanyl, remifentanil and dexmedetomidine. Compared with other groups, the modified OAA/S scores were significantly lower in DK group at 0, 5 and 10 minutes after arrival at the PACU (P < 0.05), whereas the pain VAS and BIS were not significantly different from other groups. The blood pressure and heart rate in the DK group were significantly lower than those of other groups at the PACU (P < 0.05). DK group, at sedative doses, had the better postoperative hemodynamic stability than RK group or FK group and demonstrated a similar effect of pain control as RK group and FK group with patient awareness during sedation in the PACU. (World Health Organization registry, KCT0001524).

Adverse neurologic effects of medications commonly used in the intensive care unit

Adverse drug effects often complicate the care of critically ill patients. Therefore, each patient's medical history, maintenance medication, and new therapies administered in the intensive care unit must be evaluated to prevent unwanted neurologic adverse effects. Optimization of pharmacotherapy in critically ill patients can be achieved by considering the need to reinitiate home medications, and avoiding drugs that can decrease the seizure threshold, increase sedation and cognitive deficits, induce delirium, increase intracranial pressure, or induce fever. Avoiding medication-induced neurologic adverse effects is essential in critically ill patients, especially those with neurologic injury.

Racemic ketamine in adult head injury patients: use in endotracheal suctioning

INTRODUCTION

Endotracheal suctioning (ETS) is essential for patient care in an ICU but may represent a cause of cerebral secondary injury. Ketamine has been historically contraindicated for its use in head injury patients, since an increase of intracranial pressure (ICP) was reported; nevertheless, its use was recently suggested in neurosurgical patients. In this prospective observational study we investigated the effect of ETS on ICP, cerebral perfusion pressure (CPP), jugular oxygen saturation (SjO2) and cerebral blood flow velocity (mVMCA) before and after the administration of ketamine.

METHODS

In the control phase, ETS was performed on patients sedated with propofol and remifentanil in continuous infusion. If a cough was present, patients were assigned to the intervention phase, and 100 γ/kg/min of racemic ketamine for 10 minutes was added before ETS.

RESULTS

In the control group ETS stimulated the cough reflex, with a median cough score of 2 (interquartile range (IQR) 1 to 2). Furthermore, it caused an increase in mean arterial pressure (MAP) (from 89.0 ± 11.6 to 96.4 ± 13.1 mmHg; P <0.001), ICP (from 11.0 ± 6.7 to 18.5 ± 8.9 mmHg; P <0.001), SjO2 (from 82.3 ± 7.5 to 89.1 ± 5.4; P = 0.01) and mVMCA (from 76.8 ± 20.4 to 90.2 ± 30.2 cm/sec; P = 0.04). CPP did not vary with ETS. In the intervention group, no significant variation of MAP, CPP, mVMCA, and SjO2 were observed in any step; after ETS, ICP increased if compared with baseline (15.1 ± 9.4 vs. 11.0 ± 6.4 mmHg; P <0.05). Cough score was significantly reduced in comparison with controls (P <0.0001).

CONCLUSIONS

Ketamine did not induce any significant variation in cerebral and systemic parameters. After ETS, it maintained cerebral hemodynamics without changes in CPP, mVMCA and SjO2, and prevented cough reflex. Nevertheless, ketamine was not completely effective when used to control ICP increase after administration of 100 γ/kg/min for 10 minutes.

Comparison of an Intraoperative Infusion of Dexmedetomidine or Remifentanil on Perioperative Haemodynamics, Hypnosis and Sedation, and Postoperative Pain Control

This prospective, randomized, double-blind study compared the effects of dexmedetomidine and remifentanil on haemodynamic stability, sedation and postoperative pain control in the postanaesthetic care unit (PACU). Fifty consecutive patients scheduled for total laparoscopic hysterectomy were randomly assigned to receive infusions of either dexmedetomidine (1 μg/kg) i.v. over 10 min followed by 0.2-0.7 μg/kg per h continuous i.v. infusion or remifentanil (0.8-1.2 μg/kg) i.v. over 1 min followed by 0.05-0.1 μg/kg i.v. per min, starting at the end of surgery to the time in the PACU. Modified observer's assessment of alertness scores were significantly lower in the dexmedetomidine group than in the remifentanil group at 0, 5 and 10 min after arrival in the PACU. Blood pressure and heart rate in the dexmedetomidine group were significantly lower than that recorded in the remifentanil group in the PACU. Dexmedetomidine, at the doses used in this study, had a significant advantage over remifentanil in terms of postoperative haemodynamic stability.

Remifentanil, a different opioid: potential clinical applications and safety aspects

IMPORTANCE OF THE FIELD

Opioids play an important role in every aspect of modern anesthetic practice. Remifentanil is an ultra-short-acting opioid featuring a unique pharmacokinetic profile allowing clinical versatility and improved control of its action. In this review, we assess the pharmacology of remifentanil, its clinical uses as well as safety issues on its action on the major organ systems and in particular clinical settings.

AREAS COVERED IN THIS REVIEW

A synthesis of evidence from a MEDLINE search for articles from 1993 to 2009 for available up-to-date information on remifentanil and its current applications and safety profile.

WHAT THE READER WILL GAIN

A synopsis of the unique pharmacokinetic properties of remifentanil and its action on major organ systems will provide insight on the safe and effective use of the drug in a variety of clinical settings.

TAKE HOME MESSAGE

Remifentanil is a valuable opioid in the armamentarium of the clinician, providing great clinical flexibility and safety but vigilance is required to avoid pitfalls.

Sedation and analgesia in children with developmental disabilities and neurologic disorders

Sedation and analgesia performed by the pediatrician and pediatric subspecialists are becoming increasingly common for diagnostic and therapeutic purposes in children with developmental disabilities and neurologic disorders (autism, epilepsy, stroke, obstructive hydrocephalus, traumatic brain injury, intracranial hemorrhage, and hypoxic-ischemic encephalopathy). The overall objectives of this paper are (1) to provide an overview on recent studies that highlight the increased risk for respiratory complications following sedation and analgesia in children with developmental disabilities and neurologic disorders, (2) to provide a better understanding of sedatives and analgesic medications which are commonly used in children with developmental disabilities and neurologic disorders on the central nervous system.

Intensive care management of acute stroke: general management

For a long time, patients with severe stroke were facing therapeutic nihilism of the attending physicians. Implementation of do-not-resuscitate-orders may have lead to self-fulfilling prophecies and to a pessimistic overestimation of prognosis of severe stroke syndromes. However, there have been great advances in intensive care management of acute stroke patients and it has been shown that treatment on a specialised neurological intensive care unit improves outcome. In this review, we will present a summary of the current state-of-the-art intensive care management of acute stroke patients. After presenting an overview on general management of stroke intensive care patients, special aspects of neurological intensive care of acute large middle cerebral artery stroke, intracerebral haemorrhage and subarachnoid haemorrhage will be discussed. In part II of the review, surgical management options for acute stroke will be discussed in detail.

Drugs of anaesthesia and cancer

Anaesthesia represents one of the most important medical advances in history, and, nowadays, can widely be considered safe, thanks to the discovery of new drugs and the adoption of modern technologies. Nevertheless, anaesthetic practices still represent cause for concern regarding the consequences they produce. Various anaesthetics are frequently used without knowing their effects on specific diseases: despite having been reported that invasion or metastasis of cancer cells easily occurs during surgical procedures, numerous anaesthetics are used for cancer resection even if their effect on the behaviour of cancer cells is unclear. Guidelines for a proper use of anaesthetics in cancer surgery are not available, therefore, the aim of the present review is to survey available up-to-date information on the effects of the most used drugs in anaesthesia (volatile and intravenous anaesthetics, nitrous oxide, opioids, local anaesthetics and neuromuscular blocking drugs) in correlation to cancer. This kind of knowledge could be a basic valuable support to improve anaesthesia performance and patient safety.

Remifentanil and the brain

BACKGROUND AND AIM

Remifentanil is an ultra-short-acting opioid, increasingly used today in neuroanesthesia and neurointensive care. Its characteristics make remifentanil a potentially ideal agent, but previous data have cast a shadow on this opioid, supporting potentially toxic effects on the ischemic brain. The aim of the present concise review is to survey available up-to-date information on the effects of remifentanil on the central nervous system.

METHOD

A MEDLINE search within the past seven years for available up-to-date information on remifentanil and brain was performed.

RESULTS

Concise up-to-date information on the effects of remifentanil on the central nervous system was reported, with a particular emphasis on the following topics: cerebral metabolism, electroencephalogram, electrocorticography, motor-evoked potentials, regional cerebral blood flow, cerebral blood flow velocity, arterial hypotension and hypertension, intracranial pressure, cerebral perfusion pressure, cerebral autoregulation, cerebrovascular CO(2) reactivity, cerebrospinal fluid, painful stimulation, analgesia and hyperalgesia, neuroprotection, neurotoxicity and hypothermia.

CONCLUSION

The knowledge of the influence of remifentanil on brain functions is crucial before routine use in neuroanesthesia to improve anesthesia performance and patient safety as well as outcome.

Critical care sedation for neuroscience patients

In 2000, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) introduced the mandate for the implementation of standards for both pain assessment and need for therapy in hospitalized patients. The need for the appropriate titration of sedation and analgesia is particularly poignant in an intensive care unit (ICU) setting where iatrogenic discomfort often complicates patient management. Neurologically ill patients in ICUs present particularly complex sedation issues, owing to the need to monitor these patients with serial neurological exams. Hence, maximal comfort without diminishing neurological responsiveness is desirable. Here, we review the frequently applied methods of evaluating levels of pain and agitation in critically ill patients as well as discuss the appropriate classes of pharmaceutical agents common to this population, with particular emphasis on the potential neurophysiological impact of such therapy.

Anaesthetic management of neurosurgical patients

Anaesthetic care of neurosurgical patients increasingly involves management issues that apply not only to 'asleep patients', but also to 'awake and waking-up patients' during and after intracranial operations. On one hand, awake brain surgery poses unique anaesthetic challenges for the provision of awake brain mapping, which requires that a part of the procedure is performed under conscious patient sedation. Recent case reports suggest that local infiltration anaesthesia combined with sedative regimens using short-acting drugs and improved monitoring devices have assumed increasing importance. These techniques may optimize rapid adjustments of the narcotic depth, providing analgesia and patient immobility yet permitting a swift return to cooperative patient alertness for functional brain tests. Regional anaesthesia and peripheral nerve blocks were used to prevent uncontrolled movements in special cases of intractable seizures. However, few of these strategies have been evaluated in controlled trials. Awake craniotomy for tumour removal is performed as early discharge surgery. Meticulous consideration of postoperative patient safety is therefore strongly advised. On the other hand, waking-up patients or the emergence from general anaesthesia after brain surgery is still an area with considerable variation in clinical practice. Developments indicate that fast-acting anaesthetic agents and prophylactic strategies to prevent postoperative complications minimize the adverse effects of anaesthesia on the recovery process. Recent data do not advocate a delay in extubating patients when neurological impairment is the only reason for prolonged intubation. An appropriate choice of sedatives and analgesics during mechanical ventilation of neurosurgical patients allows for a narrower range of wake-up time, and weaning protocols incorporating respiratory and neurological measures may improve outcome. In conclusion, despite a lack of key evidence to request 'fast-tracking pathways' for neurosurgical patients, innovative approaches to accelerate recovery after brain surgery are needed.

[Sedoanalgesia with remifentanil in definitive pacemaker implant]

OBJECTIVE

Describe the use of remifentanil in definitive pacemaker implant.

DESIGN

Prospective, observational study.

SCOPE

Intensive Care Unit of two general hospitals.

PATIENTS

Ninety-four patients subjected to DPM implant under sedation with remifentanil.

INTERVENTIONS

The protocol for DPM implant was conducted: premedication with metoclopramide, remifentanil perfusion (20 micro g/ml), local infiltration with mepivacaine 2%, administration of magnesium metamizole at the end of the implant and posterior discontinuation of remifentanil. Remifentanil perfusion was initiated at 2 micro g/minute, increasing it until reaching a sedation grade 2-3 on the Ramsay scale, with a maximum of 6 micro g/minute. MAIN ENDPOINTS: Time needed to reach the desired sedation grade and duration of sedation, maximum dose of remifentanil necessary, frequency that another sedation was needed and of adverse events were recorded. Continuous quantitative endpoints were expressed as mean +/- SD.

RESULTS

A sedation grade 2-3 was achieved with a perfusion rhythm of 3.6 +/- 1.4 micro g/min, in 20 +/- 22 minutes. In 89 patients (94.6%), the implant was performed only with remifentanil. Frequency of adverse events were nauseas/vomiting 21.3%, hypotension 5.3% and respiratory depression 1%. Remifentanil perfusion was discontinued in 3 patients (3.2%) due to appearance of adverse events. Another sedoanalgesic was used in 2 patients (2.1%).

CONCLUSIONS

Remifentanil is useful in the implant of DPM as a sedoanalgesia method. Serious undesired effects are rare. Future studies are necessary to completely establish its effectiveness and safety in these types of procedures.

Remifentanil

Remifentanil (Ultiva), a 4-anilidopiperidine derivative of fentanyl, is an ultra-short-acting micro-opioid receptor agonist indicated to provide analgesia and sedation in mechanically ventilated intensive care unit (ICU) patients.Analgesia-based sedation with remifentanil is a useful option for mechanically ventilated patients in the ICU setting. Its unique properties (e.g. organ-independent metabolism, lack of accumulation, rapid offset of action) set it apart from other opioid agents. Remifentanil is at least as effective as comparator opioids such as fentanyl, morphine and sufentanil in providing pain relief and sedation in mechanically ventilated ICU patients. Moreover, it allows fast and predictable extubation, as well as being associated with a shorter duration of mechanical ventilation and quicker ICU discharge than comparators in some studies. In addition, remifentanil is generally well tolerated in this patient population. Thus, remifentanil is a welcome addition to the currently available pharmacological agents employed in the management of mechanically ventilated ICU patients.

Sevoflurane-remifentanil vs isoflurane-remifentanil for the surgical correction of craniosynostosis in infants

BACKGROUND

The aim of the present study was to compare the efficacy of isoflurane-remifentanil and sevoflurane-remifentanil combinations during neurosurgical correction craniosynostosis.

METHODS

Twenty-two infants with craniosynostosis received a slow bolus of remifentanil followed by continuous infusion. The infants were randomly divided into two groups: remifentanil followed by sevoflurane (the 'sevoflurane group'), and remifentanil followed by isoflurane (the 'isoflurane group'). We monitored electrocardiogram (ECG), heart rate (HR), invasive arterial blood pressure (IABP), pulse oximetry saturation (SpO(2)), endtidal CO(2) (P(ECO(2))), inspired fraction of oxygen (FiO(2)) and endtidal volatile agent (PE volatile agent) at 12 time points, from the beginning of surgery (T0) until the cessation of drugs (T11). The volatile agent was stopped prior to skin suture and the remifentanil infusion after skin closure. Subsequently, we evaluated recovery time of spontaneous breathing and spontaneous eye opening and time of extubation at 5, 10, and 15 min after extubation, the Steward Recovery Score (SRS) was assessed. Patients were then transferred to the Pediatric Intensive Care Unit (PICU).

RESULTS

During the surgical procedure the hemodynamic parameters between the two groups did not show statistically significant differences. There were also no significant differences in terms of awakening time or SRS.

CONCLUSIONS

The rapid recovery of the children (confirmed by their high values of SRS) makes it possible to reliably assess the patient's neurological condition immediately after surgery.

Decreased duration of mechanical ventilation when comparing analgesia-based sedation using remifentanil with standard hypnotic-based sedation for up to 10 days in intensive care unit patients: a randomised trial [ISRCTN47583497]

INTRODUCTION

This randomised, open-label, multicentre study compared the safety and efficacy of an analgesia-based sedation regime using remifentanil with a conventional hypnotic-based sedation regime in critically ill patients requiring prolonged mechanical ventilation for up to 10 days.

METHODS

One hundred and five randomised patients received either a remifentanil-based sedation regime (initial dose 6 to 9 microg kg(-1) h(-1) (0.1 to 0.15 microg kg(-1) min(-1)) titrated to response before the addition of midazolam for further sedation (n = 57), or a midazolam-based sedation regime with fentanyl or morphine added for analgesia (n = 48). Patients were sedated to an optimal Sedation-Agitation Scale (SAS) score of 3 or 4 and a pain intensity (PI) score of 1 or 2.

RESULTS

The remifentanil-based sedation regime significantly reduced the duration of mechanical ventilation by more than 2 days (53.5 hours, P = 0.033), and significantly reduced the time from the start of the weaning process to extubation by more than 1 day (26.6 hours, P < 0.001). There was a trend towards shortening the stay in the intensive care unit (ICU) by 1 day. The median time of optimal SAS and PI was the same in both groups. There was a significant difference in the median time to offset of pharmacodynamic effects when discontinuing study medication in patients not extubated at 10 days (remifentanil 0.250 hour, comparator 1.167 hours; P < 0.001). Of the patients treated with remifentanil, 26% did not receive any midazolam during the study. In those patients that did receive midazolam, the use of remifentanil considerably reduced the total dose of midazolam required. Between days 3 and 10 the weighted mean infusion rate of remifentanil remained constant with no evidence of accumulation or of a development of tolerance to remifentanil. There was no difference between the groups in SAS or PI score in the 24 hours after stopping the study medication. Remifentanil was well tolerated.

CONCLUSION

Analgesia-based sedation with remifentanil was well tolerated; it reduces the duration of mechanical ventilation and improves the weaning process compared with standard hypnotic-based sedation regimes in ICU patients requiring long-term ventilation for up to 10 days.

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.

Remifentanil in the management of severe tetanus

A 61-yr-old woman presented with severe tetanus. Her intensive care management was complicated by severe generalized tetanic spasms despite the use of propofol, midazolam, alfentanil, magnesium sulphate, and atracurium. We describe the management of this problem with a variable dose remifentanil infusion.

The Effects of Remifentanil on Endotracheal Suctioning-Induced Increases in Intracranial Pressure in Head-Injured Patients

In patients with severe traumatic brain injury, bronchotracheal toilet may be accompanied by deleterious variations in intracranial pressure (ICP). To avoid these effects, IV opioids have been proposed. Twenty mechanically-ventilated patients received 3 ascending IV doses of remifentanil: dose 1 (1 microg/kg bolus, 0.25 microg/kg/min infusion); dose 2 (2 microg/kg bolus, 0.5 microg/kg/min infusion); and dose 3: (4 microg/kg bolus, 1 microg/kg/min infusion). Endotracheal suction was performed 20 min after the beginning of infusion to assess coughing. Heart rate, ICP, mean arterial blood pressure (MAP), cerebral perfusion pressure (CPP), middle cerebral artery mean flow velocity (V(MCA)), and bispectral index were monitored throughout the 30-min study period. Twelve, 15, and 19 patients receiving dose 1, 2, and 3, respectively, required vasopressors to maintain CPP >60 mm Hg. Suctioning resulted in coughing in 16, 15, and 5 patients receiving dose 1, 2, and 3, respectively. An increase in ICP, without change in V(MCA), corresponded to the reduction in MAP consistent with the preservation of autoregulation. Remifentanil used as a continuous infusion in head-injured patients is not an effective drug to block responses to suctioning.

Arrêt de la sédation en neuroréanimation

The reasons for sedation in neurointensive care can be divided into two main groups: (i) general indications, as for other intensive care patients, such as to allow the necessary treatments (therapeutic facilitation), controlling the states of agitations em leader; (ii) specific indications due to the neuro-physiologic effect of the sedatives: facilitation of the control of the intracranial pressure and lowering of the cortical excitability during the epileptic fits and thereby helping the recovery of the cerebral tissue and diminishing the secondary brain insults. It is important to remember that sedation is usually combined with the administration of opioids, which can potentiate the effect of the sedative drugs. The interruption of the sedation can be long- or short-termed. The definitive interruption is possible once the clinical and cerebral state of the patient does not justify any sedation, whereas the brief interruption allows a neurological reassessment. The amount of literature on sedation in intensive care is opposed to the few studies on neurointensive care: in January 2003, the American Society of Intensive Care has published recommendations for this topic without mentioning the interruption of sedation in neurointensive care patients. The aim of this article is to review the literature about the effects of the interruption of the sedation in neurointensive care patients.

Comparative tolerability of sedative agents in head-injured adults

Sedative agents are widely used in the management of patients with head injury. These drugs can facilitate assisted ventilation and may provide useful reductions in cerebral oxygen demand. However, they may compromise cerebral oxygen delivery via their cardiovascular effects. In addition, individual sedative agents have specific and sometimes serious adverse effects. This review focuses on the different classes of sedative agents used in head injury, with a discussion of their role in the context of clinical pathophysiology. While there is no sedative that has all the desirable characteristics for an agent in this clinical setting, careful titration of dose, combination of agents, and a clear understanding of the pathophysiology and pharmacology of these agents will allow safe sedative administration in head injury.

Pharmacokinetics of remifentanil and its major metabolite, remifentanil acid, in ICU patients with renal impairment †

BACKGROUND

The pharmacokinetics of remifentanil, an opioid analgesic metabolized by non-specific esterases, and its principal metabolite, remifentanil acid (RA), which is excreted via the kidneys, were assessed as part of an open-label safety study in intensive care unit (ICU) patients with varying degrees of renal impairment.

METHODS

Forty adult ICU patients with normal/mildly impaired renal function (creatinine clearance [CL(cr)] 62.9 (sd) 14.5 ml min(-1); n=10) or moderate/severe renal impairment (CL(cr) 14.7 (15.7) ml min(-1); n=30) were included. Remifentanil was infused for up to 72 h, at a starting rate of 6-9 microg kg(-1) h(-1) titrated to achieve a target sedation level, with additional propofol (0.5 mg kg(-1) h(-1)) if required. Intensive arterial sampling was performed for up to 72 h after infusion. Pharmacokinetic parameters obtained by simultaneous modelling of remifentanil and RA data were statistically compared between the two groups.

RESULTS

Remifentanil pharmacokinetics were not significantly affected by renal status. RA clearance in the moderate/severe group was reduced to about 25% that of the normal/mild group (41 (29) vs 176 (49) ml kg(-1) h(-1), P<0.0001). Metabolic ratio, a predictor of the ratio of RA to remifentanil concentrations at steady state, was approximately eight-fold higher in the moderate/severe group relative to the normal/mild group (116 (110) vs 15 (4), P<0.0001). Maximum RA levels approached 700 ng ml(-1) in the moderate/severe group.

CONCLUSIONS

Although RA accumulates in patients with moderate/severe renal impairment, pharmacokinetic modelling predicts that RA concentrations during a 9 microg kg(-1) h(-1) remifentanil infusion for up to 15 days would not exceed those reported in the present study, for which no associated prolongation of mu-opioid effects was observed.

Offset of pharmacodynamic effects and safety of remifentanil in intensive care unit patients with various degrees of renal impairment

INTRODUCTION

This open label, multicentre study was conducted to assess the times to offset of the pharmacodynamic effects and the safety of remifentanil in patients with varying degrees of renal impairment requiring intensive care.

METHODS

A total of 40 patients, who were aged 18 years or older and had normal/mildly impaired renal function (estimated creatinine clearance >/= 50 ml/min; n = 10) or moderate/severe renal impairment (estimated creatinine clearance <50 ml/min; n = 30), were entered into the study. Remifentanil was infused for up to 72 hours (initial rate 6-9 microgram/kg per hour), with propofol administered if required, to achieve a target Sedation-Agitation Scale score of 2-4, with no or mild pain.

RESULTS

There was no evidence of increased offset time with increased duration of exposure to remifentanil in either group. The time to offset of the effects of remifentanil (at 8, 24, 48 and 72 hours during scheduled down-titrations of the infusion) were more variable and were statistically significantly longer in the moderate/severe group than in the normal/mild group at 24 hours and 72 hours. These observed differences were not clinically significant (the difference in mean offset at 72 hours was only 16.5 min). Propofol consumption was lower with the remifentanil based technique than with hypnotic based sedative techniques. There were no statistically significant differences between the renal function groups in the incidence of adverse events, and no deaths were attributable to remifentanil use.

CONCLUSION

Remifentanil was well tolerated, and the offset of pharmacodynamic effects was not prolonged either as a result of renal dysfunction or prolonged infusion up to 72 hours.

Remifentanil versus fentanyl for analgesia based sedation to provide patient comfort in the intensive care unit: a randomized, double-blind controlled trial [ISRCTN43755713]

INTRODUCTION

This double-blind, randomized, multicentre study was conducted to compare the efficacy and safety of remifentanil and fentanyl for intensive care unit (ICU) sedation and analgesia.

METHODS

Intubated cardiac, general postsurgical or medical patients (aged >/= 18 years), who were mechanically ventilated for 12-72 hours, received remifentanil (9 microgram/kg per hour; n = 77) or fentanyl (1.5 microgram/kg per hour; n = 75). Initial opioid titration was supplemented with propofol (0.5 mg/kg per hour), if required, to achieve optimal sedation (i.e. a Sedation-Agitation Scale score of 4).

RESULTS

The mean percentages of time in optimal sedation were 88.3% for remifentanil and 89.3% for fentanyl (not significant). Patients with a Sedation-Agitation Scale score of 4 exhibited significantly less between-patient variability in optimal sedation on remifentanil (variance ratio of fentanyl to remifentanil 1.84; P = 0.009). Of patients who received fentanyl 40% required propofol, as compared with 35% of those who received remifentanil (median total doses 683 mg and 378 mg, respectively; P = 0.065). Recovery was rapid (median time to extubation: 1.1 hours for remifentanil and 1.3 hours for fentanyl; not significant). Remifentanil patients who experienced pain did so for significantly longer during extubation (6.5% of the time versus 1.4%; P = 0.013), postextubation (10.2% versus 3.6%; P = 0.001) and post-treatment (13.5% versus 5.1%; P = 0.001), but they exhibited similar haemodynamic stability with no significant differences in adverse event incidence.

CONCLUSION

Analgesia based sedation with remifentanil titrated to response provided effective sedation and rapid extubation without the need for propofol in most patients. Fentanyl was similar, probably because the dosing algorithm demanded frequent monitoring and adjustment, thereby preventing over-sedation. Rapid offset of analgesia with remifentanil resulted in a greater incidence of pain, highlighting the need for proactive pain management when transitioning to longer acting analgesics, which is difficult within a double-blind study but would be quite possible under normal circumstances.

A low-dose remifentanil infusion is well tolerated for sedation in mechanically ventilated, critically-ill patients

PURPOSE

To study the analgesic and sedative effects of remifentanil in critically-ill patients.

METHODS

Remifentanil infusion was started at 0.02 microg x kg(-1) x min(-1) in ten mechanically ventilated critically-ill patients, and the infusion rate was increased to 0.05, 0.10, 0.15, 0.20, and 0.25 microg x kg(-1) x min(-1) every 30 min. Basally and 25 min after each increase we measured: the Ramsey sedation score (RSS) and the respiratory response subscore of comfort scale (CSRR); the bispectral index (BIS) before and after lightly touching tracheal mucosa; heart rate and systemic arterial pressure; respiratory variables; plasma epinephrine and norepinephrine levels.

RESULTS

Infusion rates up to 0.05 microg x kg(-1) x min(-1) were effective against agitation and achieved a good degree of adaption to the respirator in all patients (RSS 2 or more and CSRR 3 or less); BIS decreased significantly; respiratory and circulatory variables were unaffected; mean plasma epinephrine levels decreased. At infusion rates higher than 0.05 microg x kg(-1) x min(-1) RSS but not BIS decreased further and patient arousability caused by noxious stimuli was not prevented; respiratory drive suppression occurred at the infusion rates higher than 0.05 microg x kg(-1) x min(-1) in four patients; bradycardia and arterial hypotension was observed in three patients; plasma epinephrine levels decreased significantly, while norepinephrine was unaffected; severe itching was experienced by one patient.

CONCLUSIONS

Low doses of remifentanil (up to 0.05 microg x kg(-1) x min(-1)) can be useful in critically-ill patients in order to achieve calm and sedation. Higher doses can inhibit respiratory drive and require controlled mechanical ventilation.

New agents for sedation in the intensive care unit

Several advances are likely to benefit the ICU patient requiring sedation, analgesia, and anxiolysis. The cooperative sedation induced by dexmedetomidine is a unique and valuable state that allows patients to be aroused easily and interferes little with ventilation. Remifentanil is the prototype of short-acting drugs, providing fast onset and offset; its relatively high cost may be balanced by limiting the risk for long-lasting respiratory depression. Lorazepam seems to be finding more proponents, especially in long-term ICU sedation where the costs of the newer agents may be prohibitive.

Effects of remifentanil/propofol in comparison with isoflurane on dynamic cerebrovascular autoregulation in humans

BACKGROUND

This study investigates the effects of remifentanil and propofol in comparison to isoflurane on dynamic cerebrovascular autoregulation in humans.

METHODS

In 16 awake patients dynamic cerebrovascular autoregulation was measured using transcranial Doppler sonography (TCD). Thereafter patients were intubated, ventilated with O2/air (FiO2=0.33) and randomly assigned to one of the following anesthetic protocols: group 1 (n=8): 0.5 microg x kg(-1) x min(-1) remifentanil combined with a propofol-target plasma concentration of 1.5 microg x ml(-1) group 2 (n=8): 1.8 % isoflurane (1.5 MAC). Following 20 min of equilibration the autoregulatory challenge was repeated. Arterial blood gases and body temperature were maintained constant over time.

STATISTICS

Mann-Whitney U-test and Wilcoxon signed-rank test.

RESULTS

Dynamic autoregulation was intact in all patients prior to induction of anesthesia expressed by an autoregulatory index (ARI) of 5.4+/-1.21 (mean+/-SD, group 1) and 5.9+/-0.98 (mean+/-SD, group 2). With remifentanil/propofol anesthesia dynamic autoregulation was similar to the awake state (group 1: ARI=4.9+/-0.88). In contrast, autoregulatory response was delayed with 1.5 MAC isoflurane (group 2, ARI=2.1+/-0.92) (P<0.05).

CONCLUSION

These data show that dynamic cerebrovascular autoregulation is maintained with remifentanil-based total intravenous anesthesia. This is consistent with the view that narcotics (and hypnotics) do not alter the physiologic cerebrovascular responses to changes in MAP. In contrast, 1.5 MAC isoflurane delays cerebrovascular autoregulation compared to the awake state.

Remifentanil

Remifentanil is an opioid with a unique pharmacokinetic profile. Its metabolism by nonspecific esterases results in rapid and uniform clearance leading to highly predictable onset and offset of action. This review will describe the features that set remifentanil apart from other opioids and outline its potential usefulness in a critical care setting. Most studies on remifentanil have been in postoperative neurosurgical and cardiothoracic ICU settings. In the former, the agent has proved especially useful because rapid predictable emergence from sedation allows regular clinical evaluation. Remifentanil also prevents procedure-associated rise in intracranial pressure. In the cardiac setting, the drug provides excellent intraoperative hemodynamic control while allowing return of spontaneous ventilation within minutes of discontinuation of the infusion. One study suggests that the use of remifentanil will reduce the need for postoperative intensive care, especially after hepatic transplantation.

Intracranial pressure and surgical decompression for traumatic brain injury: biological rationale and protocol for a randomized clinical trial

Commonly, severe traumatic brain injury (TBI) patients undergo amputation of contused brain; the rationale being that edema in presumed unsalvageable cerebrum increases intracranial pressure (ICP). Neuro-critical care expends great effort to control ICP and prevent secondary injury. Non-randomized investigations have employed hemicraniectomy with duraplasty after developing refractory ICP. We undertook a randomized pilot of hemicraniectomy with duraplasty as the initial surgery for severe TBI patients. Goals included reduced ICP therapeutic intensity and return to the operating room, and improved neurological outcome. Upon hospital presentation, the study was to randomize 92 patients with midline shift greater than the size of a surgically removable hematoma. One group was to receive standardized hemicraniectomy and duraplasty; the other would undergo 'traditional' craniotomy (with brain amputation at the neurosurgeon's discretion). A standardized medical protocol followed. The six-month Glasgow Outcome Scale was the primary outcome, with secondary measures including quality of life one year after TBI, duration and frequency of elevated ICP, intensive care unit (ICU) therapeutic intensity, operating room return, and ICU and hospital lengths-of-stay. This article presents the biological rationale and the evidence-based standardized protocols of the study and its outcome measures. The study has stopped and a phase III outcome trial is being organized.

Isoflurane improves long-term neurologic outcome versus fentanyl after traumatic brain injury in rats

Despite routine use of fentanyl in patients after traumatic brain injury (TBI), it is unclear if it is the optimal sedative/analgesic agent. Isoflurane is commonly used in experimental TBI. We hypothesized that isoflurane would be neuroprotective versus fentanyl after TBI. Rats underwent controlled cortical impact (CCI) and received 4 h of N2O/O2 (2:1) and either fentanyl (10 microg/kg i.v. bolus, 50 microg/kg/h infusion) or isoflurane (1% by inhalation) with controlled ventilation. Shams underwent identical preparation, without CCI. Functional outcome (beam balance, beam walking, Morris water maze [MWM] tasks) was assessed over 20 days. Lesion volume and hippocampal neuron survival were quantified on day 21. Additional rats underwent identical CCI and anesthesia with intracranial pressure (ICP) monitoring, and brain water content was assessed. Motor and MWM performances were better in injured rats treated with isoflurane versus fentanyl (p < 0.05). CA1 hippocampal damage was attenuated in isoflurane-treated rats (p < 0.05). Fentanyl-treated rats had higher mean arterial blood pressure after injury (p < 0.05); however, ICP and brain water were similar between groups. Isoflurane improved functional outcome and attenuated damage to CA1 versus fentanyl in rats subjected to CCI. Isoflurane may be neuroprotective by augmenting cerebral blood flow and/or reducing excitotoxicity, not by reducing ICP or brain water content. Alternatively, fentanyl may be detrimental. Isoflurane may mask beneficial effects of novel agents tested in TBI models. Additionally, fentanyl may not be optimal early after TBI in humans.

Evaluation of intravenous parecoxib for the relief of acute post-surgical pain

Parecoxib is a prodrug of valdecoxib, which is a potent and selective inhibitor of COX-2. Intravenous preparation of parecoxib is in Phase III clinical trials for the management of acute and severe post-surgical pain. It is the only COX-2 inhibitor that is available in a parenteral formulation. Clinical results compare parecoxib with ketorolac, a NSAID, which is the only non-narcotic analgesic available in parenteral formulation that can be administered for the relief of moderate to severe acute pain. Pharmacokinetic studies have shown that parecoxib is converted to valdecoxib within a short time following administration by im. or iv. injection. In clinical trials, parecoxib compares favourably with ketorolac and produces less gastric or duodenal ulcers, the predominant adverse effect, than ketorolac. Parecoxib, thus, fulfils some of the desirable characteristics of an ideal non-narcotic analgesic for severe post-surgical pain and has application in other acutely painful conditions. Parecoxib is expected to be filed for approval before the end of 2000 and is expected to be introduced in the market in 2001. It has favourable prospects for a fair share of the post-surgical pain relief market which is valued at approximately US$ 1 billion for the year 2000.