Sufentanil, fentanyl, and alfentanil in head trauma patients: a study on cerebral hemodynamics

Safety and efficacy of analgesia-based sedation with remifentanil versus standard hypnotic-based regimens in intensive care unit patients with brain injuries: a randomised, controlled trial [ISRCTN50308308]

Introduction

This randomised, open-label, observational, multicentre, parallel group study assessed the safety and efficacy of analgesia-based sedation using remifentanil in the neuro-intensive care unit.

Methods

Patients aged 18–80 years admitted to the intensive care unit within the previous 24 hours, with acute brain injury or after neurosurgery, intubated, expected to require mechanical ventilation for 1–5 days and requiring daily downward titration of sedation for assessment of neurological function were studied. Patients received one of two treatment regimens. Regimen one consisted of analgesia-based sedation, in which remifentanil (initial rate 9 μg kg^-1 h^-1) was titrated before the addition of a hypnotic agent (propofol [0.5 mg kg^-1 h^-1] during days 1–3, midazolam [0.03 mg kg^-1 h^-1] during days 4 and 5) (n = 84). Regimen two consisted of hypnotic-based sedation: hypnotic agent (propofol days 1–3; midazolam days 4 and 5) and fentanyl (n = 37) or morphine (n = 40) according to routine clinical practice. For each regimen, agents were titrated to achieve optimal sedation (Sedation–Agitation Scale score 1–3) and analgesia (Pain Intensity score 1–2).

Results

Overall, between-patient variability around the time of neurological assessment was statistically significantly smaller when using remifentanil (remifentanil 0.44 versus fentanyl 0.86 [P = 0.024] versus morphine 0.98 [P = 0.006]. Overall, mean neurological assessment times were significantly shorter when using remifentanil (remifentanil 0.41 hour versus fentanyl 0.71 hour [P = 0.001] versus morphine 0.82 hour [P < 0.001]). Patients receiving the remifentanil-based regimen were extubated significantly faster than those treated with morphine (1.0 hour versus 1.93 hour, P = 0.001) but there was no difference between remifentanil and fentanyl. Remifentanil was effective, well tolerated and provided comparable haemodynamic stability to that of the hypnotic-based regimen. Over three times as many users rated analgesia-based sedation with remifentanil as very good or excellent in facilitating assessment of neurological function compared with the hypnotic-based regimen.

Conclusions

Analgesia-based sedation with remifentanil permitted significantly faster and more predictable awakening for neurological assessment. Analgesia-based sedation with remifentanil was very effective, well tolerated and had a similar adverse event and haemodynamic profile to those of hypnotic-based regimens when used in critically ill neuro-intensive care unit patients for up to 5 days.

Quand et comment débuter une sédation en neuroréanimation ?

Sedatives drugs are part of the everyday care in the neuro-ICU. Reasons to sedate patients in neuro-ICU are as usual to ensure the comfort and to secure the patients, to permit nursing as well as to permit adaptation to the ventilator. But some objectives are specific in neuro-ICU as optimisation of cerebral haemodynamics and oxygenation, and to avoid a convulsive state or a dysautonomic syndrome. Starting the sedation usually necessitate a tracheal intubation and mechanical ventilation. Patients presenting with intracranial hypertension are at risk of developing cerebral ischaemia in case of cerebral haemodynamics alteration associated with anaesthetic drugs injection. Morphinomimetics increase intracranial pressure (ICP), but cerebral perfusion pressure and oxygenation (CPP) remain usually unaltered. Injection of an intravenous bolus of thiopental or propofol lowers ICP and CPP, but also the cerebral tissular oxygen consumption: the cerebral oxygenation seems therefore protected. The succinylcholine used for emergency tracheal intubation has no effect on the cerebral haemodynamic. Some more studies are needed to better understand the cerebral oxygenation at the local level when sedative drugs are injected or perfused in patients with intracranial hypertension.

Les agents utilisés pour la sédation en neuro-réanimation

Sedation and analgesia can be routinely prescribed in head injury patients. The goals of such sedation are three: brain protection, prevention and treatment of intracranial hypertension and therapeutic facilitation. In such situation, the use of sedative and analgesic therapy should respect the rate of cerebral blood flow/cerebral oxygen consumption coupling while preserving cerebral perfusion pressure and decreasing the intracranial pressure. This treatment should have an analgesic and myorelaxing action with short and predictable time of action. The ideal sedation agent with all these properties does not exist. Only the combination of several different pharmacological classes of compounds may reach this goal. Benzodiazepines are the most frequently used agents. In most of the cases they are associated with analgesic agents such as opioid or ketamine. Opioids may be the basic analgesic agents because they do not produce brain haemodynamic modifications if arterial pressure is maintained. Among them, sufentanil, thanks to its pharmacokinetics properties, remains the most prescribed opioid. However, in the future, remifentanil that presents a fast elimination may be more frequently used for neurological follow up of patients. Ketamine whose use is subject of debate, has the main advantage of maintaining haemodynamic status. Ketamine has no side effects on brain haemodynamic when used with propofol or midazolam. Taking into account their deleting effect on haemodynamic status and immune system, barbituric are no longer used as long term sedative agents. However, their use is still recommended in the cases of refractory intracranial hypertension. Propofol remains the ideal sedative agent because of its short duration action but its use is limited by its cost. Its use may be recommended for short time sedations with or without an opioid drug. The curare use should be restrain to refractory intracranial hypertension to usual treatments and happening during stimulation.

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.

Les morphiniques (sufentanil et rémifentanil) en neuro-anesthésie

Remifentanil is the latest available compound of the 4-anilidopiperidine derivatives. It is characterized by an ultrashort duration of action and a metabolism independent of both hepatic and renal functions. Its main drawback is a lack of residual analgesia and the risk of postoperative hyperalgesia. Since its introduction in clinical practice, this drug has been compared to other congeners in a few studies in the setting of neurosurgery. Cerebral hemodynamics, intracranial pressure and CO(2) reactivity are similar to the effects of fentanyl and sufentanil provided that systemic arterial pressure is maintained. Haemodynamics does not greatly vary according to the type of the opioid. Fentanyl and sufentanil require higher hypnotic dosage (halogenated agents, propofol) and remifentanil is accompanied by greater volumes of fluid infusion. A marked reduction in extubation times and superior level of consciousness are reported with remifentanil. Rescue analgesic has to be given faster but pain scores remain low. Morphine 0.08 mg/kg IV administered at bone replacement results in good postoperative analgesia without delayed recovery. In summary, remifentanil is appropriate when rapid recovery and neurological evaluation are desired. Conversely, sufentanil is more suitable and easier to administer when postoperative mechanical ventilation and postponed awakening are scheduled.

Safety of sedation with ketamine in severe head injury patients: comparison with sufentanil

OBJECTIVE

The aim of the study was to compare the safety concerning cerebral hemodynamics of ketamine and sufentanil used for sedation of severe head injury patients, both drugs being used in combination with midazolam.

DESIGN

Prospective, randomized, double-blind study.

SETTING

Intensive care unit in a trauma center.

PATIENTS

Twenty-five patients with severe head injury.

INTERVENTIONS

Twelve patients received sedation with a continuous infusion of ketamine-midazolam and 13 with a continuous infusion of sufentanil-midazolam. All patients were mechanically ventilated with moderate hyperventilation.

MEASUREMENTS AND MAIN RESULTS

Prognostic indicators (age, Glasgow Coma Scale scores, computed tomography diagnosis, and Injury Severity Scale score) were similar in the two groups at study entry. Measurements were carried out during the first 4 days of sedation. The average infusion rates during this time were 82 +/- 25 micro x kg x min ketamine and 1.64 +/- 0.5 microg x kg x min midazolam in the ketamine group and 0.008 +/- 0.002 microg x kg x min sufentanil and 1.63 +/- 0.37 microg x kg x min midazolam in the sufentanil group. No significant differences were observed between the two groups in the mean daily values of intracranial pressure and cerebral perfusion pressure. The numbers of intracranial pressure elevations were similar in both groups. The requirements of neuromuscular blocking agents, propofol, and thiopental were similar. Heart rate values were significantly higher in the ketamine group on therapy days 3 and 4 ( <.05). With regard to arterial pressure control, more fluids were given on the first therapy day and there was a trend toward greater use of vasopressors in the sufentanil group. Sedative costs were similar in the two groups.

CONCLUSION

The results of this study suggest that ketamine in combination with midazolam is comparable with a combination of midazolam-sufentanil in maintaining intracranial pressure and cerebral perfusion pressure of severe head injury patients placed under controlled mechanical ventilation.

Advances and Controversies in Adult ICU Sedation, Part 3: Evolving Pharmacological Treatment Issues

This feature examines the impact of pharmacologic interventions on the treatment of the critically ill patient—an area of health care that has become increasingly complex. It will review recent advances (including evolving and controversial data) in drug therapy for adult ICU patients and assess these new modalities in terms of clinical, humanistic, and economic outcomes.

Cerebral perfusion during anesthesia with fentanyl, isoflurane, or pentobarbital in normal rats studied by arterial spin-labeled MRI

The influence of anesthetic agents on cerebral blood flow (CBF) was tested in normal rats. CBF is quantified with arterial spin-labeled MRI in rats anesthetized with either an opiate (fentanyl), a potent inhalation anesthetic agent (isoflurane), or a barbiturate (pentobarbital) using doses commonly employed in experimental paradigms. CBF values were found to be about 2.5-3 times lower in most regions analyzed during anesthesia with either fentanyl (with N(2)O/O(2)) or pentobarbital vs. isoflurane (with N(2)O/O(2)), in agreement with findings utilizing invasive measurement techniques. CBF was heterogeneous in rats anesthetized with isoflurane (with N(2)O/O(2)), but relatively homogeneous in rats anesthetized with either fentanyl (with N(2)O/O(2)) or pentobarbital, also in agreement with studies using other techniques. Magn Reson Med 46:202-206, 2001.

Use of sedative and analgesic agents in neurotrauma patients: effects on cerebral physiology

Sedation and analgesia is used primarily in the intensive care unit (ICU) to limit the stress response to critical illness, provide anxiolysis, improve ventilatory support, and facilitate adequate ICU care. However, in the neurotrauma ICU there are many other reasons for the use of these agents. The primary aim is to prevent secondary cerebral damage by maintaining adequate cerebral perfusion pressures. This is accomplished in several different ways. Controlling intracranial pressure (ICP) and maintaining an adequate mean arterial pressure (MAP) is at the cornerstone of this management. Lowering the metabolic demands of the brain is also an important consideration as a treatment strategy. Analgesic and sedative agents are utilized to prevent undesirable increases in ICP and to lower cerebral metabolic demands. Concerns surrounding the use of these agents include time to awakening after discontinuation, effect on the cerebrovasculature, and the effect on patient outcome. There are many different pharmacological agents available, each with their distinct advantages and disadvantages. The purpose of this review is to evaluate the pharmacokinetic and pharmacological effects of each of these agents when used in neurotrauma patients.

Anaesthesia for interventional neuroradiology

Neuroradiologists have extended their treatment modalities in the field of vascular neurosurgery. The rapidly emerging and re-engineered neuroradiological techniques confront the anaesthetist with an increasing number of patients with severe neurological disease. More of these patients will need general anaesthesia in order to facilitate the endovascular procedure, including catheter placement, deposition of embolic material, and improved imaging. Anaesthetists are challenged by additional anaesthesiological aspects previously not encountered in neuroanaesthesia. A safe anaesthetic management is based on a broad understanding of pathophysiological and technical issues that arise with the endovascular treatment of cerebral vasculopathy.

Intensive care unit management of the stroke patient

Although the majority of patients with acute stroke do not require intensive care, it is important to recognize when admission to an intensive care unit (ICU) is warranted. Patients undergoing thrombolytic therapy, those with brainstem infarcts referable to the basilar artery, those with large space occupying hemispheric infarcts, and those with fluctuating neurological examinations should be admitted to the ICU for monitoring and treatment.