No reduction in the sufentanil requirement of elderly patients undergoing ventilatory support in the medical intensive care unit

Monitoring of sedation depth in intensive care unit by therapeutic drug monitoring? A prospective observation study of medical intensive care patients

Background

Analgosedation is a cornerstone therapy for mechanically ventilated patients in intensive care units (ICU). To avoid inadequate sedation and its complications, monitoring of analgosedation is of great importance. The aim of this study was to investigate whether monitoring of analgosedative drug concentrations (midazolam and sufentanil) might be beneficial to optimize analgosedation and whether drug serum concentrations correlate with the results of subjective (Richmond Agitation-Sedation Scale [RASS]/Ramsay Sedation Scale) and objective (bispectral (BIS) index) monitoring procedures.

Methods

Forty-nine intubated, ventilated, and analgosedated critically ill patients treated in ICU were clinically evaluated concerning the depth of sedation using RASS Score, Ramsay Score, and BIS index twice a day. Serum concentrations of midazolam and sufentanil were determined in blood samples drawn at the same time. Clinical and laboratory data were statistically analyzed for correlations using the Spearman’s rank correlation coefficient rho (ρ).

Results

Average age of the population was 57.8 ± 16.0 years, 61% of the patients were males. Most frequent causes for ICU treatments were sepsis (22%), pneumonia (22%), or a combination of both (25%). Serum concentrations of midazolam correlated weakly with RASS (ρ = − 0.467) and Ramsay Scores (ρ = 0.476). Serum concentrations of sufentanil correlated weakly with RASS (ρ = − 0.312) and Ramsay Scores (ρ = 0.295). Correlations between BIS index and serum concentrations of midazolam (ρ = − 0.252) and sufentanil (ρ = − 0.166) were low.

Conclusion

Correlations between drug serum concentrations and clinical or neurophysiological monitoring procedures were weak. This might be due to intersubject variability, polypharmacy with drug-drug interactions, and complex metabolism, which can be altered in critically ill patients. Therapeutic drug monitoring is not beneficial to determine depth of sedation in ICU patients.

Electronic supplementary material

The online version of this article (10.1186/s40560-018-0331-7) contains supplementary material, which is available to authorized users.

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.

Pharmacology of commonly used analgesics and sedatives in the ICU: benzodiazepines, propofol, and opioids

The ideal sedative or analgesic agent should have a rapid onset of activity, a rapid recovery after drug discontinuation, a predictable dose response, a lack of drug accumulation,and no toxicity. Unfortunately, none of the earlier analgesics, the benzodiazepines,or propofol share all of these characteristics. Patients who are critically ill experience numerous physiologic derangements and commonly require high doses and long durations of analgesic and sedative therapy. There is a paucity of well designed clinical trials evaluating the safety and efficacy of earlier sedative and analgesic agents in the ICU. In addition, the ever-changing dynamics of patients who are critically ill makes the use of sedation a continual challenge during the course of each patient’s admission. To optimize care, clinicians should be familiar with the many pharmacokinetic, pharmacodynamic, and pharmacogenetic variables that can affect the safety and efficacy of sedatives and analgesics.

Rémifentanil-midazolam versus sufentanil-midazolam pour la sédation prolongée en réanimation

OBJECTIVE

Remifentanil has a unique metabolic pathway that holds potential benefits for long-term sedation. We compared remifentanil-midazolam to sufentanil-midazolam in 41 critically ill adults requiring mechanical ventilation.

STUDY DESIGN

Randomized double-blind trial.

PATIENTS AND METHODS

Infusion rates were titrated every 4 hours to achieve the desired Ramsay score. Five fold increases in dose requirement was considered as the development of tolerance. Drugs requirement, development of tolerance and weaning time of ventilation were compared.

RESULTS

The study was stopped after an interim analysis. The remifentanil and sufentanil groups were comparable regarding IGS II: 56+/-22 vs 64+/-26, mean+/-SD, ICU length of stay: 26 (8-45) vs 19 (11-34) days, and sedation duration: 6 (4-19) vs 6 (3-16)days, median [interquartile range, IQR]). There was a shorter weaning time in the remifentanil group as compared to sufentanil group: 22 h (12-53) vs 96 (47-142) h, median [IQR], p=0.04). The daily opioid infusion rate needed to be decreased over time only in sufentanil group, p < 0.001. Tolerance occurred in 6 (30%; CI(95), 10 to 40%) remifentanil and no sufentanil patients (P=0.02).

CONCLUSION

Sufentanil infusion needed to be reduced over time and prolonged the weaning time when compared to remifentanil.

Pharmacokinetics of long-term sufentanil infusion for sedation in ICU patients

OBJECTIVE

To determine the pharmacokinetics of long-term infusion of sufentanil in ICU patients.

DESIGN AND SETTING

Open-label study in a surgical intensive care unit.

PATIENTS

Ten consecutive patients without renal or hepatic failure requiring mechanical ventilation for at least 6 days.

INTERVENTIONS

Patients received sufentanil (initial bolus 0.5 micro g/kg and continuous infusion rate of 0.5 micro g/kg per hour) and midazolam (initial bolus 0.08 mg/kg and continuous infusion 0.05 mg/kg per hour). Sedation was adjusted according to the Ramsay scale (score >3). Blood samples were taken during and up to 72 h after the infusion, and plasma concentrations were measured using a sensitive radioimmunoassay method.

MEASUREMENTS AND RESULTS

Plasma concentration-time profiles of sufentanil and pharmacokinetic parameters such as initial postinfusion half-life (t(1/2alpha)), elimination half-life (t(1/2beta)), total clearance (Cl), volume of distribution (Vdbeta), and time required to obtain a 50% decrease in plasma concentration (tcp(0/2)). The mean duration of sedation was 12+/-7 days. The initial half-life t(1/2alpha) was 1.33+/-1.15 h. The observed prolonged elimination half-life (t(1/2beta)=25.5+/-9.4 h) was related to the large volume of distribution (Vdbeta=22.6+/-9.4 l/kg). The mean total clearance was 13.4+/-7.0 ml/kg per minute. The mean time required to obtain a 50% decrease in plasma concentration was short (tcp(0/2=)4.7+/-3.7 h).

CONCLUSIONS

The pharmacokinetic analysis of sufentanil for ICU sedation revealed increased volume of distribution and elimination half-life. Nevertheless the rapid distribution and elimination processes suggest that the rapid reversibility of sedation with sufentanil is maintained after long duration of infusion. Further studies should be carried out to evaluate the clinical relevance of these results.

Analgesic agents. Pharmacology and application in critical care

Evaluation of analgesic agents is multifactorial. The authors know of no direct comparisons among the choices in analgesic agents that suggest one therapy over another in global outcomes such as mortality or morbidity. Therefore, until further outcome differentiation between agents is proved, understanding the primary difference of delivery routes, mechanisms of action, pharmacokinetics, and adverse effects serves as the best guide for selecting the appropriate agent for each patient.

Anaesthesia for procedures in the intensive care unit

Taking in charge severely ill patients in the intensive care environment to manage complex procedures is a performance requiring highly specific knowledge. Close collaboration between anaesthetists and intensive care specialists is likely to improve the safety and quality of medical care. Three forms of anaesthetic care should be considered in clinical practice: sedation and analgesia; monitored anaesthetic care; and general anaesthesia or conduction block anaesthesia. Even in the field of sedation and analgesia, the anaesthesiologist can offer expertise on new anaesthetic techniques like: the most recent concepts of balanced anaesthesia in terms of pharmacokinetics and dynamics, favouring the use of short-acting agents and of sedative-opioid combinations. New modes of administration and monitoring intravenous anaesthesia have been developed, with potential application in the intensive care unit. These include the use of target-controlled administration of intravenous drugs, and of electroencephalographic signals to monitor the level of sedation.

Recovery after remifentanil and sufentanil for analgesia and sedation of mechanically ventilated patients after trauma or major surgery

We investigated the analgesic effect and the neurological recovery time after administration of remifentanil in mechanically ventilated patients in an intensive care unit. Twenty patients, after trauma or major surgery with no intracranial pathology, were randomized to receive either remifentanil/propofol (n=10) or sufentanil/propofol (n=10). A sedation score and a simplified pain score were used to assess adequate sedation and analgesia. Medication was temporarily stopped after 24 h. Immediately before and 10 and 30 min after, the degree of sedation and pain score were evaluated. Adequate analgesia and sedation was achieved with remifentanil 10.6 microg kg(-1) h(-1) and propofol 2.1 mg kg(-1) h(-1), or sufentanil 0.5 microg kg(-1) h(-1) and propofol 1.3 mg kg(-1) h(-1). The difference in propofol dose between groups was significant. Ten minutes after terminating the medication, the degree of sedation decreased significantly after remifentanil and all patients could follow simple commands. During the following 20 min, all patients with remifentanil emerged from sedation and complained of considerable pain. By contrast, in the sufentanil group, only six (7) responded to commands after 10 (30) min and their pain score remained essentially unchanged during the 30-min observation period. We conclude that, in contrast to sufentanil, remifentanil facilitates rapid emergence from analgesia and sedation, allowing a clinical neurological examination within 10-30 min in mechanically ventilated patients with no intracranial pathology.