Nociception-guided versus Standard Care during Remifentanil-Propofol Anesthesia: A Randomized Controlled Trial

Effect of dexmedetomidine on Nociception Level Index-guided remifentanil antinociception: A randomised controlled trial

BACKGROUND

The effect of dexmedetomidine on Nociception Level Index-guided (Medasense, Israel) antinociception to reduce intra-operative opioid requirements has not been previously investigated.

OBJECTIVE

We aimed to determine if low-dose dexmedetomidine would reduce remifentanil requirements during Nociception Level Index-guided antinociception without increasing complications associated with dexmedetomidine.

DESIGN

Double-blind randomised controlled trial.

SETTING

Two university teaching hospitals in Brussels, Belgium.

PATIENTS

American Society of Anesthesiologists 1 and 2 patients (n = 58) undergoing maxillofacial or cervicofacial surgery under propofol--remifentanil target-controlled infusion anaesthesia.

INTERVENTIONS

A 30 min infusion of dexmedetomidine, or equal volume of 0.9% NaCl, was infused at 1.2 μg kg-1 h-1 immediately preceding induction and then decreased to 0.6 μg kg-1 h-1 until 30 min before ending surgery. Nociception Level Index and frontal electroencephalogram guided the remifentanil and propofol infusions, respectively.

MAIN OUTCOMES

The primary outcome was the remifentanil requirement. Other outcomes included the propofol requirement, cardiovascular status and postoperative outcome.

RESULTS

Mean ± SD remifentanil (3.96 ± 1.95 vs. 4.42 ± 2.04 ng ml-1; P = 0.0024) and propofol (2.78 ± 1.36 vs. 3.06 ± 1.29 μg ml-1; P = 0.0046) TCI effect site concentrations were lower in the dexmedetomidine group at 30 min postincision and remained lower throughout surgery. When remifentanil (0.133 ± 0.085 vs. 0.198 ± 0.086 μg kg-1 min-1; P = 0.0074) and propofol (5.7 ± 2.72 vs. 7.4 ± 2.80 mg kg-1 h-1; P = 0.0228) requirements are represented as infusion rates, this effect became statistically significant at 2 h postincision.

CONCLUSION

In ASA 1 and 2 patients receiving Nociception Level Index-guided antinociception, dexmedetomidine decreases intra-operative remifentanil requirements. Combined frontal electroencephalogram and Nociception Level Index monitoring can measure dexmedetomidine's hypnotic and opioid-sparing effects during remifentanil-propofol target-controlled infusion anaesthesia.

TRIAL REGISTRATIONS

Clinicaltrials.gov: NCT03912740, EudraCT: 2018-004512-22.

Analgesia Nociception Index (ANI) and ephedrine: a dangerous liasion

The Analgesia Nociception Index is a dimensionless scale derived from the heart rate variability; by analyzing the heart rate variability oscillations, it reflects the activity of the sympathetic and parasympathetic nervous systems and ultimately helps to evaluate the Nociception-Antinociception balance during anesthesia and surgery. Drugs like ephedrine affect the heart rate variability inducing artifacts in the ANI readings which should be taken into account in the clinical practice and in clinical research.

Effects of pupillary reflex dilation-guided opioid administration on remifentanil and morphine consumption during laparoscopic surgery: A randomised controlled trial

BACKGROUND

Analysis of pupillary reflex dilation (PRD) assesses the balance of nociception--antinociception. Laparoscopic surgery induces haemodynamic variations that are misleading. During laparoscopy, PRD guidance helps differentiate haemodynamic changes because of excess nociception from secondary changes related to the reflex release of endocrine factors.

OBJECTIVE

The present study evaluated the effect of PRD-guided antinociception on the administration of intra-operative remifentanil and immediate postoperative morphine consumption in patients undergoing elective laparoscopic surgery.

DESIGN

The study was a single-blind, randomised controlled trial.

SETTING

The study took place at two sites at the University Hospital of Nancy from March 2014 to November 2017.

PATIENTS

A total of 100 patients who underwent scheduled laparoscopic surgery were included.

INTERVENTIONS

Patients were randomly given remifentanil guided by PRD (PRD-guided) or standard anaesthesia care (control).

MAIN OUTCOME MEASURES

The primary outcome was intra-operative remifentanil consumption. Secondary outcomes included morphine consumption in the immediate postoperative period and the number of intra-operative haemodynamic events.

RESULTS

Data from 95 patients were analysed. Intraoperative remifentanil consumption was lower in the PRD-guided group than in the control group: median [IQR], 0.09 [0.07 to 0.11] vs. 0.14 [0.12 to 0.16] μg kg min, with a mean difference (95% confidence Interval, CI) of 0.048 (0.035 to 0.060) μg kg min; P < 0.0001. Morphine consumption was 0.13 [0.1 to 0.5] vs. 0.15 [0.11 to 0.4] mg kg (P = 0.52) in the PRD-guided and control groups, respectively. The number of hypertensive and tachycardia events was greater in the PRD-guided group than in the control group: Hypertensive events 60.4 vs. 32.6%, relative risk 1.85 (95% CI, 1.24 to 2.84), P = 0.004; tachycardia events 31.6% vs. 4.3%, relative risk 2.09 (95% CI, 1.45 to 2.84), P < 0.001.

CONCLUSIONS

When PRD is used to differentiate between haemodynamic events arising from noxious stimuli and those events because of other nonsurgical stimuli, then intra-operative remifentanil administration is reduced intra-operatively during laparoscopic surgery but there was no change in postoperative morphine consumption.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02116868.

Effects of noxious stimulation on the electroencephalogram during general anaesthesia: a narrative review and approach to analgesic titration

Electroencephalographic (EEG) activity is used to monitor the neurophysiology of the brain, which is a target organ of general anaesthesia. Besides its use in evaluating hypnotic states, neurophysiologic reactions to noxious stimulation can also be observed in the EEG. Recognising and understanding these responses could help optimise intraoperative analgesic management. This review describes three types of changes in the EEG induced by noxious stimulation when the patient is under general anaesthesia: (1) beta arousal, (2) (paradoxical) delta arousal, and (3) alpha dropout. Beta arousal is an increase in EEG power in the beta-frequency band (12-25 Hz) in response to noxious stimulation, especially at lower doses of anaesthesia drugs in the absence of opioids. It is usually indicative of a cortical depolarisation and increased cortical activity. At higher concentrations of anaesthetic drug, and with insufficient opioids, delta arousal (increased power in the delta band [0.5-4 Hz]) and alpha dropout (decreased alpha power [8-12 Hz]) are associated with noxious stimuli. The mechanisms of delta arousal are not well understood, but the midbrain reticular formation seems to play a role. Alpha dropout may indicate a return of thalamocortical communication, from an idling mode to an operational mode. Each of these EEG changes reflect an incomplete modulation of pain signals and can be mitigated by administration of opioid or the use of regional anaesthesia techniques. Future studies should evaluate whether titrating analgesic drugs in response to these EEG signals reduces postoperative pain and influences other postoperative outcomes, including the potential development of chronic pain.

Nociception level index: do intra-operative values allow the prediction of acute postoperative pain?

Nociception Level Index (NOL) guided analgesia has previously been found to correlate with noxious stimuli during surgery. It was aim of this study to investigate the relationship between intra-operative NOL and acute postoperative pain. After IRB approval, 80 patients scheduled for non-emergency surgery were enrolled. NOL data were recorded from induction of anaesthesia until the end of surgery. After admission to the postoperative acute care unit (PACU), pain scores (numeric rating scale [NRS, 0-10] were obtained 5-minutely for 15 min. NOL data of 74 patients were analyzed. Receiver-operating curve (ROC) analysis identified the NOL reaction to the knife to skin incision (median NOL within 60 s post knife to skin) vs. the median NOL during surgery vs. NOL at the end of surgery to have the highest correlation coefficient (ρ = 0.3; P = 0.01) as well as the highest area under the ROC curve (AUC 0.68; P = 0.01) for the prediction of moderate-severe pain in PACU. A NOL > 20 after skin incision predicted moderate-severe postoperative pain with the highest combined sensitivity (73%) and specificity (58%). A NOL < 10 after skin incision excluded moderate-severe pain in PACU with a negative predictive value of 83%. The NOL reaction to skin incision, but not NOL during surgery appears to allow the exclusion and, to a lesser degree the prediction of moderate-severe pain in PACU. The results may also strengthen the manufacturers recommendation of an intraoperative NOL range of 10-25.Australian New Zealand Clinical Trials Registry: ACTRN12619001596190.

Nociception level-guided opioid administration in radical retropubic prostatectomy: a randomised controlled trial

BACKGROUND

This RCT investigated the effect of opioid titration by three different nociception monitoring devices or clinical signs during general anaesthesia.

METHODS

Ninety-six patients undergoing radical retropubic prostatectomy with propofol/remifentanil anaesthesia were randomised into one of four groups to receive remifentanil guided by one of three nociception monitoring devices (surgical pleth index [SPI], pupillary pain index [PPI], or nociception level [NOL]) or by clinical judgement (control). Intraoperative remifentanil requirement was the primary endpoint, whereas recovery parameters and stress hormone levels were secondary endpoints.

RESULTS

The mean [95% confidence interval {CI}] remifentanil administration rate differed between the groups: control 0.34 (0.32-0.37), SPI 0.46 (0.38-0.55), PPI 0.07 (0.06-0.08), and NOL 0.16 (0.12-0.21) μg kg^-1 min^-1(P<0.001). Intraoperative cessation of remifentanil administration occurred in different numbers (%) of patients: control 0 (0%), SPI 1 (4.3%), PPI 18 (75.0%), and NOL 11 (47.8%); P=0.002. The area under the curve analyses indicated differences in cumulative cortisol levels (mg L^-1 min^-1) amongst the groups: control 37.9 (33.3-43.1), SPI 38.6 (33.8-44.2), PPI 72.1 (63.1-82.3), and NOL 54.4 (47.6-62.1) (mean [95% CI]). Pairwise group comparison results were as follows: control vs SPI, P=0.830; control vs PPI, P<0.001; control vs NOL, P=0.001; SPI vs PPI, P<0.001; SPI vs NOL, P=0.002; and PPI vs NOL, P=0.009.

CONCLUSIONS

The nociception monitoring devices and clinical signs reflect the extent of nociception differently, leading to dissimilar doses of remifentanil. Very low remifentanil doses were associated with an increase and higher remifentanil doses were accompanied by a decrease in serum cortisol concentrations. Use of nociception monitoring devices for guiding intra-operative opioid dosing needs further validation.

CLINICAL TRIAL REGISTRATION

NCT03380949.

A beat-by-beat cardiovascular index, CARDEAN, to titrate opioid administration in the setting of orthopaedic surgery: a prospective randomized trial

To determine whether a beat-by-beat cardiovascular index (CARDEAN: cardiovascular depth of analgesia, Alpha-2 Ltd, Lyon, France) reduces the incidence of tachycardia in ASA I-III patients undergoing orthopaedic surgery. A total of 76 patients were prospectively randomized into (1) a control group or (2) the CARDEAN group, in which the nurse anaesthetist was blinded to CARDEAN application. In addition to conventional signs, an external observer instructed the nurse anaesthetist to administer sufentanil 0.1 µg kg^-1 when the CARDEAN crossed a threshold (≥ 60). The primary outcome was the incidence of tachycardia (> 120% of reference heart rate, HR). Non-invasive blood pressure (BP), electrocardiogram (ECG), O₂ saturation-photoplethysmography and the bispectral index (40 < BIS < 60) were monitored. HR and an estimation of beat-by-beat BP changes acquired from photoplethysmography and ECG were combined in an algorithm that detected hypertension followed by tachycardia (index scaled 0-100). Sufentanil 0.1 µg kg^-1 was administered when tachycardia, hypertension or movement ("conventional signs") was observed. Data for 66 patients (27 with known hypertension) were analysed. In the CARDEAN group, (a) the dose of sufentanil was higher (control: 0.46 µg kg^-1 100 min^-1, CARDEAN: 0.57 µg kg^-1 100 min^-1, p = 0.016), (b) the incidence rates of tachycardia and untoward events were lower (respectively: - 44%; control: 2.52 events 100 min^-1 [1.98-3.22]; CARDEAN: 1.42 [1.03-1.96], p = 0.005, hazard ratio: 0.56; movement, muscular contraction, or coughing: control: 0.74 events 100 min^-1 [0.47-1.16]; CARDEAN: 0.31 [0.15-0.62], p = 0.038), and (c) extubation occurred more often in the operating room (control: 76.5%, CARDEAN: 97%, p = 0.016). CARDEAN-titrated opioid administration was associated with a higher dose of sufentanil, a reduction in tachycardia and earlier emergence in ASA I-III patients undergoing major orthopaedic surgery.

Reduced postoperative pain using Nociception Level-guided fentanyl dosing during sevoflurane anaesthesia: a randomised controlled trial

Background

The majority of postoperative patients report moderate to severe pain, possibly related to opioid underdosing or overdosing during surgery. Objective guidance of opioid dosing using the Nociception Level (NOL) index, a multiparameter artificial intelligence-driven index designed to monitor nociception during surgery, may lead to a more appropriate analgesic regimen, with effects beyond surgery. We tested whether NOL-guided opioid dosing during general anaesthesia results in less postoperative pain.

Methods

In this two-centre RCT, 50 patients undergoing abdominal surgery under fentanyl/sevoflurane anaesthesia were randomised to NOL-guided fentanyl dosing or standard care in which fentanyl dosing was based on haemodynamics. The primary endpoint of the study was postoperative pain assessed in the PACU.

Results

Median postoperative pain scores were 3.2 (inter-quartile range 1.3–4.3) and 4.8 (3.0–5.3) in NOL-guided and standard care groups, respectively (P=0.006). Postoperative morphine consumption (standard deviation) was 0.06 (0.07) mg kg⁻¹ (NOL-guided group) and 0.09 (0.09) mg kg⁻¹ (control group; P=0.204). During surgery, fentanyl dosing was not different between groups (NOL-guided group: 6.4 [4.2] μg kg⁻¹vs standard care: 6.0 [2.2] μg kg⁻¹, P=0.749), although the variation between patients was greater in the NOL-guided group (% coefficient of variation 66% in the NOL-guided group vs 37% in the standard care group).

Conclusions

Despite absence of differences in fentanyl and morphine consumption during and after surgery, a 1.6-point improvement in postoperative pain scores was observed in the NOL-guided group. We attribute this to NOL-driven rather than BP- and HR-driven fentanyl dosing during anaesthesia.

Clinical trial registration

www.trialregister.nl under identifier NL7845.

Does nociception monitor-guided anesthesia affect opioid consumption? A systematic review of randomized controlled trials

Monitors that estimate nociception during anesthesia may be used to guide opioid and other analgesics administration to optimize anesthesia care and possibly outcome. We reviewed the literature to evaluate current evidence of the effect of nociception-guided management over standard anesthesia practice during surgery. A systematic review of the literature on the effect of nociception monitoring on anesthesia practice was conducted. Reports were eligible if they compared nociception-guided anesthesia to standard practice during surgery. Primary endpoint of this review is intraoperative opioid consumption. Secondary endpoints included hemodynamic control, postoperative pain and pain treatment. We identified 12 randomized controlled trials that compared one of five different nociception monitoring techniques to standard anesthesia care. Most studies were single center studies of small sample size. Six studies reported intraoperative opioid consumption as primary outcome. There was considerable variability with respect to surgical procedure and anesthesia technique. For nociception monitors that were investigated by more than one study, analysis of the pooled data was performed. The surgical plethysmographic index was the only monitor for which an intra operative opioid sparing effect was found. For the other monitors, either no effect was detected, or pooled analysis could not be performed due to paucity of study data. On secondary outcomes, no consistent effect of nociception-guided anesthesia could be established. Although some nociception monitors show promising results, no definitive conclusions regarding the effect of nociception monitoring on intraoperative opioid consumption or other anesthesia related outcome can be drawn.Clinical trial number PROSPERO ID 102913.

Predictive value of the surgical pleth index for the hemodynamic responses to trachea intubation and skin incision

Surgical pleth index (SPI) has been widely investigated in assessing the nociceptive level. The aim of this study was to investigate the relationship between SPI level and patient responses to trachea intubation and skin incision. A total of 40 patients undergoing open abdominal general surgery were recruited for analyses. The patients were monitored with electrocardiogram, non-invasive blood pressure, SpO₂, invasive blood pressure and SPI before anesthesia induction. Anesthesia was induced with midazolam, propofol, sufentanil and rocuronium and maintained with sufentanil and sevoflurane. Blood pressure, heart rate and SPI were recorded for analyses during the peri-intubation and peri-incision periods. A receiver operating characteristic (ROC) curve analysis was performed to analyze the predictive value of blood pressure, heart rate (HR) and SPI for hemodynamic responses for trachea intubation and skin incision. SPI had a similar changing trend to systolic blood pressure (SBP) and diastolic blood pressure (DBP). The SPI level was linearly correlated with SBP, DBP and HR. SPI increased significantly after intubation and incision in patients with positive but not negative responses to intubation and incision. The ROC analysis showed that only SBP level is predictive of intubation responses. These data suggested that SPI elevated under the noxious stimulation by intubation and incision, but it was not predictive of the hemodynamic responses to intubation and incision.

Evaluation of the Intraoperative Perfusion Index for Correlation with Acute Postoperative Pain in Patients Undergoing Laparoscopic Colorectal Cancer Surgery

Despite technical advancements in the perioperative management of cancer surgery, postoperative pain remains a significant clinical issue. We examined the diagnostic value of the intraoperative perfusion index for predicting acute postoperative pain in patients undergoing laparoscopic colorectal cancer surgery. We retrospectively analyzed data for 105 patients who had undergone laparoscopic colorectal cancer surgery. Patients with pain scores <7 and ≥7 on a 10-point scale upon arrival in the postoperative anesthesia care unit (PACU) were categorized into the N and P groups, respectively. The perfusion index value was extracted prior to intubation, at the start and end of surgery, and after extubation. To minimize individual variance in the absolute value of the perfusion index, we calculated the perfusion index change ratio. A total of 98 patients were examined. Among them, 50 (51.0%) and 48 (49.0%) patients reported pain scores of <7 and ≥7 upon arrival at the PACU, respectively. Fentanyl consumption during the intraoperative and PACU periods was significantly higher in Group P than in Group N (p < 0.001). The perfusion index change ratios did not significantly differ between the groups. The intraoperative perfusion index change ratios do not correlate with acute postoperative pain following laparoscopic colorectal cancer surgery.