Comparison of the Surgical Pleth Index with autonomic nervous system modulation on cardiac activity during general anaesthesia: A randomised cross-over study

Abdominal Wall Block Decreases Intraoperative Opioid Con-Sumption by Surgical Pleth Index-Guided Remifentanil Administration in Single-Port Laparoscopic Herniorrhaphy: A Prospective Randomized Controlled Trial

Abdominal wall blocks (AWBs) can reduce pain during surgery and lessen opioid demand. Since it is difficult to know the exact level of intraoperative pain, it is not known how much the opioid dose should be reduced. In this study, using the surgical pleth index (SPI), which indicates pain index from sympathetic fibers, the amount of remifentanil consumption was investigated. We conducted single-port laparoscopic hernia repair in 64 patients, as follows: the regional block group (R group) was treated with AWB, while the control group (C group) was only subjected to general anesthesia. In both groups, the remifentanil concentration was adjusted to maintain the SPI score between 30 and 40 during surgery. The primary parameter was the amount of remifentanil. A total of 52 patients completed the study (24 in the R group, 28 in the C group). The remifentanil dose during surgery was decreased in the R group (29 ± 21 vs. 56 ± 36 ng/kg/min; p = 0.002). Visual analogue scale score and additional administrated analgesics were also low in the R group. As such, AWB can reduce the remifentanil dose while maintaining the same pain level.

Intraoperative Assessment of Surgical Stress Response Using Nociception Monitor under General Anesthesia and Postoperative Complications: A Narrative Review

We present a narrative review focusing on the new role of nociception monitor in intraoperative anesthetic management. Higher invasiveness of surgery elicits a higher degree of surgical stress responses including neuroendocrine-metabolic and inflammatory-immune responses, which are associated with the occurrence of major postoperative complications. Conversely, anesthetic management mitigates these responses. Furthermore, improper attenuation of nociceptive input and related autonomic effects may induce increased stress response that may adversely influence outcome even in minimally invasive surgeries. The original role of nociception monitor, which is to assess a balance between nociception caused by surgical trauma and anti-nociception due to anesthesia, may allow an assessment of surgical stress response. The goal of this review is to inform healthcare professionals providing anesthetic management that nociception monitors may provide intraoperative data associated with surgical stress responses, and to inspire new research into the effects of nociception monitor-guided anesthesia on postoperative complications.

Comparison of adequacy of anaesthesia monitoring with standard clinical practice monitoring during routine general anaesthesia: An international, multicentre, single-blinded randomised controlled trial

BACKGROUND

Previous studies have suggested that monitoring the levels of both hypnosis and antinociception could reduce periods of inadequate anaesthesia. However, the evidence regarding associated benefits of this monitoring is still limited.

OBJECTIVE

The primary objective of this study was to confirm that guidance of anaesthesia by depth of hypnosis and antinociception monitoring decreases the number of inadequate anaesthesia events in comparison with standard clinical practice.

DESIGN

A multicentre, single-blinded, randomised controlled trial.

SETTING

The study was conducted in four European University hospitals in four different countries between December 2013 and November 2016.

PATIENTS

The study population consisted of a total of 494 adult patients undergoing elective surgery requiring tracheal intubation.

INTERVENTIONS

The patients were allocated to one of two groups. The first group was treated using Entropy for depth of hypnosis and surgical pleth index to determine depth of antinociception (adequacy of anaesthesia group; AoA group). The second group was monitored using standard monitoring alone (control group). Anaesthesia was conducted with target-controlled infusions of propofol and remifentanil.

MAIN OUTCOME MEASURES

The primary outcome of the study was the number of total unwanted events for example signs of inadequately light or unintentionally deep anaesthesia.

RESULTS

Evidence of inadequate anaesthesia had an incidence of around 0.7 events per patient in both groups with no difference between groups (P = 0.519). In the AoA group, the overall consumption of propofol was significantly reduced (6.9 vs. 7.5 mg kg h, P = 0.008) in comparison with the control group. The consumption of remifentanil was equal in both groups. The times to emergence [8.0 vs. 9.6 min (P = 0.005)] and full recovery in the postanaesthesia care unit (P = 0.043) were significantly shorter in the AoA group. No differences were seen in postoperative pain scores or in the use of analgesics.

CONCLUSION

In the current study, the guidance of total intravenous anaesthesia by Entropy and surgical pleth index in comparison with standard monitoring alone was not able to validate reduction of unwanted anaesthesia events. However, there was a reduction in the use of propofol, and shorter times for emergence and time spent in the postanaesthesia care unit.

TRIAL REGISTRATION

at ClinicalTrials.gov NCT01928875.

Effect of dexmedetomidine on intraoperative Surgical Pleth Index in patients undergoing video-assisted thoracoscopic lung lobectomy

Background

The Surgical Pleth Index (SPI) is a monitoring method that reflects painful stimuli during general anesthesia, and dexmedetomidine is an analgesic adjuvant with an opioid-sparing effect. But up to now, it is still unclear whether dexmedetomidine has any influence on SPI. To investigate whether dexmedetomidine has an effect on SPI during video-assisted thoracoscopic surgery.

Methods

We enrolled 94 patients who underwent video-assisted thoracoscopic lung lobectomy. Patients were randomly assigned to a dexmedetomidine group (dexmedetomidine: 0.8 μg/kg administered for 10 min before anesthesia) or normal saline group (equal volume of normal saline). SPI and vital signs were recorded. The number rating scale (NRS) pain score was also evaluated.

Results

SPI values were significantly lower in the dexmedetomidine group than in the normal saline group at intubation and at discharge from the postanesthesia care unit. Compared with the normal saline group, mean arterial pressure and heart rate were both significantly lower in the dexmedetomidine group at intubation. Heart rate was lower at skin incision in the dexmedetomidine group. The NRS score in the normal saline group was noticeably higher vs. the dexmedetomidine group at discharge from the postanesthesia care unit.

Conclusions

Dexmedetomidine decreased intraoperative SPI and NRS scores. Our results showed that dexmedetomidine attenuated noxious stimuli.

Trial registration

Chinese Clinical Trial Registry (ChiCTR): ChiCTR-OOC-16009450, Registered 16 October, 2016.

Heart rate variability and surgical pleth index under anesthesia in poor and normal sleepers

Poor sleep quality is associated with autonomic dysfunctions and altered pain perception and tolerance. To investigate whether autonomic dysregulations related to insomnia would still exist under general anesthesia, we adopt heart rate variability (HRV) analysis to evaluate ANS activity and surgical pleth index (SPI) to compare nociceptive/anti-nociceptive balance. We enrolled 61 adult females scheduled for gynecological surgeries under general anesthesia. All the subjects were ASA Class I to III without using medicines affecting HRV. We used the Insomnia Severity Index to evaluate sleep qualities. ECG data were recorded and signals which denote four different surgical stages were extracted (baseline, incision, mid-surgery, and end of surgery). We analyzed the HRV changes across the whole surgical period and differences among good and poor sleepers. We also compared the SPI differences among groups. For baseline HRV analysis, we found significant differences in the RMSSD (p = 0.043), pNN50 (p = 0.029), VLF power (p = 0.035), LF power (p = 0.004), and HF power (p = 0.037) between the good and poor sleeper groups. However, all intergroup differences disappeared after anesthesia induction. Temporal HRV changes significantly among different perioperative stages (RMSSD, p < 0.001; pNN50, p = 0.004; LF, p < 0.001; and HF, p < 0.001). Patients with different sleep qualities did not exhibit different SPI levels in all four periods. Poor sleepers exhibited attenuated parasympathetic activities at the baseline but no differences after the induction. Nociceptive/anti-nociceptive balance seems not be altered by poor sleep condition under general anesthesia.

POSTOPERATIVE PAIN AND STRESS RESPONSE: DOES CHILD'S GENDER HAVE AN INFLUENCE?

Surgical procedure causes multisystem stress response reactions. The aim of this study was to assess whether gender has an impact on the level of neuroendocrine response to surgical stress and intensity of postoperative pain in children undergoing inguinal hernia repair surgery, as well as satisfaction of their parents with preoperative and postoperative care. The study included 60 children aged 3-6 years, all of them the only child in the family. All children included in the study were categorized as American Society of Anesthesiologists PS Class I, and divided into two groups: group 1 composed of 30 boys and group 2 composed of 30 girls. After oral premedication with midazolam, general anesthesia with endotracheal intubation was performed in all patients. Ketorolac, 1 mg.kg^-1, was administered for postoperative analgesia. Serum cortisol was measured in all children preoperatively and postoperatively. The quality of postoperative analgesia was evaluated by Wong-Baker (FACES) scale, along with parental satisfaction. Male children who were the only child in the family had stronger neuroendocrine response to surgical stress and stronger intensity of postoperative pain. The parents of the girls expressed greater satisfaction with preoperative and postoperative care.

Surgical pleth index: prospective validation of the score to predict moderate-to-severe postoperative pain

BACKGROUND

Reported outcome benefits after surgical pleth index (SPI, GE Healthcare, Helsinki, Finland) guided anaesthesia are conflicting. One potential explanation may be the lack of evidence for the selection of meaningful SPI target values. A recently published trial found an SPI cut-off of 30 as a 'best-fit' to predict moderate-to-severe acute postoperative pain. This prospective trial was designed to validate this target and to investigate the influence of patient age on SPI in this context.

METHODS

After ethics approval, 200 patients undergoing non-emergency surgery were enrolled. Data related to SPI, heart rate (HR), and mean arterial pressure (MAP) were recorded for the last 5 min of surgery, just before arousal. After admission to recovery, pain scores (numeric rating scale [NRS], 0-10) were obtained every 5 min for 15 min.

RESULTS

The data of 196 patients were analysed. Receiver-operating curve analysis showed a cut-off SPI value of 29 to be the optimum intraoperative target to discriminate between NRS 0-3 and 4-10. This confirms the 'best fit' cut-off for SPI published previously. Though still superior to HR and MAP, the sensitivity and specificity of the SPI were only poor. Age had no influence on the predictive accuracy of SPI.

CONCLUSIONS

An SPI of approximately 30 was confirmed as having the best sensitivity/specificity to predict moderate-to-severe pain in the postanaesthesia care unit. However, the predictive accuracy was overall poor and not influenced by patient age.

CLINICAL TRIAL REGISTRATION

ACTRN12617001475336.

Surgical pleth index: prediction of postoperative pain and influence of arousal

BACKGROUND

There are conflicting reports concerning the outcome after anaesthesia guided by the surgical pleth index (SPI; GE Healthcare, Helsinki, Finland). One potential explanation may be the lack of evidence for the selection of SPI cut-off values. The aim of this trial was to investigate the correlation between SPI, arousal, and postoperative pain and to define a cut-off value for SPI to predict moderate-to-severe pain.

METHODS

After obtaining ethical approval and written informed consent, 70 patients undergoing non-emergency surgery were enrolled. Data relating to SPI, heart rate, mean arterial pressure, and state entropy were recorded every 10 s for the last 10 min of surgery (state entropy <60 at all times). Subsequently, recordings continued during the phase of arousal. After recovery room admission, pain scores (numerical rating scale 0-10) were obtained every 3 min for 15 min.

RESULTS

Data from 65 patients were analysed. Receiver-operating characteristic curve analysis revealed an optimal intraoperative cut-off SPI value of 30 to discriminate between numerical rating scale scores 0-3 and 4-10. For this value, the negative and positive predictive values to discriminate between numerical rating scale scores 0-3 and 4-10 were 50 and 89.7%, respectively. The SPI was significantly affected by arousal, and SPI scores obtained during this phase were not predictive of postoperative pain.

CONCLUSIONS

Surgical pleth index values are predictive of postoperative pain only if obtained before patient arousal. In contrast to previous studies, a relatively low SPI, >30, appears to predict pain with a high positive predictive value and may therefore be suggested for future studies of SPI-guided anaesthesia.

CLINICAL TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12615000804583.

The effect of nicardipine on the surgical pleth index during thyroidectomy under general anesthesia: A prospective double-blind randomized controlled trial

BACKGROUND

The effectiveness of surgical pleth index (SPI) for managing nociception-antinociception balance during general anesthesia with vasodilators, including nicardipine has not been demonstrated. We aimed to compare the time course during surgery in SPI values in patients receiving nicardipine or remifentanil infusion during thyroidectomy.

METHODS

Forty patients undergoing thyroidectomy were randomly assigned to receive nicardipine (group N; n = 19) or remifentanil (group R; n = 21) along with induction (propofol, fentanyl, and rocuronium) and maintenance (50% desflurane/nitrous oxide in oxygen) anesthesia (goal bispectral index [BIS] ∼50). The infusion of nicardipine or remifentanil was started before the 1st incision and adjusted to keep mean blood pressure (MBP) within ±20% of the preoperative value. SPI, BIS, end-tidal desflurane concentration (EtDes), MBP, and heart rate were recorded at 2.5 minute intervals from the 1st incision to the end of surgery. Extubation and recovery times, pain score/rescue ketorolac consumption, and adverse events in postanesthesia care unit (PACU) were recorded.

RESULTS

The trend of SPI during surgery was comparable between the 2 groups (P = 0.804), although the heart rates in group N were significantly higher than those in group R (P = 0.040). The patient characteristics, trends of BIS, EtDes, and MBP during surgery, extubation and recovery times, and incidence of nausea/vomiting were comparable between the groups. Group N had significantly lower pain scores and rescue ketorolac consumption at PACU.

CONCLUSION

SPI was comparable between patients receiving nicardipine or remifentanil infusion during thyroidectomy under general anesthesia, which suggests that the administration of nicardipine may confound the interpretation of SPI values during general anesthesia.

CLINICAL TRIAL REGISTRATION

This trial was registered in the UMIN clinical trials registry (unique trial number: UMIN000019058; registration number: R000022028; principal investigator's name: Young Ju Won; date of registration: September 17, 2015).

Comparison of relative oxycodone consumption in surgical pleth index-guided analgesia versus conventional analgesia during sevoflurane anesthesia: A randomized controlled trial

BACKGROUND

The surgical pleth index (SPI) is proposed for titration of analgesic drugs during general anesthesia. Several reports have investigated the effect of SPI on the consumption of opioids including remifentanil, fentanyl, and sufentanil during anesthesia, but there are no reports about oxycodone. We aimed to investigate intravenous oxycodone consumption between SPI-guided analgesia and conventional analgesia practices during sevoflurane anesthesia in patients undergoing thyroidectomy.

METHODS

Forty-five patients undergoing elective thyroidectomy were randomly assigned to an SPI group (SPI-guided analgesia group, n = 23) or a control group (conventional analgesia group, n = 22). Anesthesia was maintained with sevoflurane to achieve bispectral index values between 40 and 60. In the SPI group, oxycodone 1 mg was administered intravenously at SPI values over 50; in the control group, oxycodone 1 mg was administered intravenously at the occurrence of tachycardia or hypertension event. Intraoperative oxycodone consumption and extubation time were recorded. The number of hemodynamic and somatic movement events was recorded, as were postoperative pain and recovery scores.

RESULTS

Patients' characteristics were comparable between the groups. Intraoperative oxycodone consumption in the SPI group was significantly lower than the control group (3.5 ± 2.4 vs 5.1 ± 2.4 mg; P = 0.012). Extubation time was significantly shorter in the SPI group (10.6 ± 3.5 vs 13.4 ± 4.6 min; P = 0.026). Hemodynamic and somatic movement events during anesthesia were comparable between the groups, as were numeric rating scales for pain and modified Aldrete scores at postanesthesia care unit.

CONCLUSIONS

SPI-guided analgesia reduces intravenous oxycodone consumption and extubation time compared with conventional analgesia based on clinical parameters during sevoflurane anesthesia in patients undergoing thyroidectomy.

Comparison of Surgical Pleth Index-guided Analgesia with Conventional Analgesia Practices in Children: A Randomized Controlled Trial

BACKGROUND

To compare surgical pleth index (SPI)-guided analgesia with conventional analgesia by evaluating intraoperative analgesic requirements, postoperative pain, and emergence agitation in children.

METHODS

This study was designed as a parallel, two-arm, double-blind, randomized controlled trial. Forty-five children undergoing elective adenotonsillectomy were randomly allocated to SPI-guided group (SPI-guided analgesia group, n = 21) or control group (conventional analgesia group, n = 24). Anesthesia was maintained with sevoflurane 2 to 3 vol% in 50% nitrous oxide and oxygen to achieve state entropy between 40 and 60. Intraoperative fentanyl 0.5 μg/kg was administered for the first event persisting 3 min and subsequent events persisting 5 min. An event was defined as an SPI over 50 (SPI-guided group) or a blood pressure or heart rate 20% above the baseline (control group). The primary outcome was intraoperative fentanyl requirement. Secondary outcomes included intraoperative sevoflurane consumption, postoperative emergence agitation and pain score, and postoperative rescue analgesic requirements.

RESULTS

Intraoperative fentanyl requirement was lower in SPI-guided group than in control group (0.43 ± 0.53 vs. 1.73 ± 0.59 μg/kg; P < 0.001). Intraoperative sevoflurane consumption was similar. The proportion of patients with high emergence agitation scores (4 to 5) was greater in SPI-guided group (61.9 vs. 25.0%; P = 0.01). The postoperative pain score and rescue fentanyl consumption were higher in SPI-guided group (7 [4.5; 9] vs. 3 [2; 6.75]; P = 0.002; 0.50 ± 0.34 vs. 0.29 ± 0.30 μg/kg; P = 0.04).

CONCLUSIONS

As currently constructed, SPI does not appear to be valid in children. This may be due to both differences in blood vessel distensibility and baseline increased heart rates in children versus adults.

Pulse Photoplethysmographic Analysis Estimates the Sympathetic Activity Directed to Heart and Vessels

BACKGROUND

Novel pulse photoplethysmographic-derived indices have been proposed as tools to measure autonomic nervous system (ANS) modulation in anesthetized and awake patients, but nowadays their experimental validation is lacking. The authors aimed to investigate the ability of pulse photoplethysmographic amplitude (PPGA), ANS state (ANSS), and ANSS index (ANSSi) to measure changes of ANS modulation in response to sympathetic stimulation.

METHODS

Ten awake healthy volunteers underwent two passive head-up tilts at 45° and 90°. The heart rate variability (HRV) and systolic arterial pressure variability were analyzed in the frequency domain as a measure of ANS modulation directed to the heart and the vessels. HRV, baroreflex sensitivity, and pulse photoplethysmographic indices were measured at baseline and after tilt maneuvers. The agreement between HRV-derived indices and pulse photoplethysmographic indices was assessed using Bland-Altman plots.

RESULTS

PPGA, ANSS, and ANSSi changed significantly during the study protocol. Head-up tilt decreased PPGA and ANSS and increased ANNSi. There was a good agreement between ANSSi and baroreflex sensitivity explored in the high-frequency band (bias, 0.23; 95% CI, -22.7 to 23.2 normalized units) and between ANSSi and the sympathovagal modulation directed to the heart (bias, 0.96; 95% CI, -8.7 to 10.8 normalized units).

CONCLUSIONS

In controlled experimental conditions, novel pulse plethysmographic indices seem to estimate the changes of the sympathetic outflow directed to the vessels and the sympathovagal balance modulating heart rate. These indices might be useful in the future to monitor the fluctuation of sympathetic activity in anesthetized patients.

Remifentanil added to sufentanil-sevoflurane anesthesia suppresses hemodynamic and metabolic stress responses to intense surgical stimuli more effectively than high-dose sufentanil-sevoflurane alone

BACKGROUND

Even extremely high-doses of the potent opioid, sufentanil, cannot reliably suppress stress responses to intense surgical stimuli such as sternotomy. The chemically related opioid remifentanil with its different pharmacokinetics and binding affinities for delta- and kappa-opioid receptors might be more effective in attenuating these responses.

METHODS

ASA I-III patients scheduled for a surgical procedure with sternotomy under balanced anesthesia (sevoflurane and sufentanil 3 μg.kg(-1) bolus, 0.017 μg.kg(-1).min(-1) infusion) were randomized into two groups. Patients in the study group were supplemented with remifentanil (2 μg.kg(-1) bolus, 2-7 μg.kg(-1).min(-1) infusion) starting ten minutes before sternotomy. Heart rate, arterial blood pressures, cardiac index, ejection fraction, systemic vascular resistance index (SVRI), total body oxygen uptake (VO2) and electric dermal response were measured and compared between the groups.

RESULTS

62 patients were studied (study group 32, control group 30). Systolic and mean arterial blood pressures, SVRI, VO2 and skin conductance increased during sternotomy and sternal spread in the control group but not in the study group. Systolic blood pressure increase: 7.5 ± 19 mmHg vs. -3.4 ± 8.9 (p = 0.005); VO2 increase: 31 ± 46% vs. -0.4 ± 32%; incidence of systolic blood pressure increase greater than 15 percent: 20% vs. 3% (p = 0.035) (control vs. study group).

CONCLUSION

High-dose remifentanil added to sevoflurane-sufentanil anesthesia suppresses the sympathoadrenergic response to sternotomy and sternal spread better than high-dose sufentanil alone.

TRIAL REGISTRATION

CLINICAL TRIAL NUMBER

DRKS00004327, August 31, 2012.