***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Surgical noxious stimuli generate a stress response with an increased sympathetic activity , potentially affecting the perioperative outcome . Surgical Pleth Index ( SPI ) , derived from the pulse plethysmogram , has been proposed as a tool to assess nociception-antinociception balance . The relationship between SPI and autonomic nervous system ( ANS ) during general anesthesia is poorly understood and it is doubtful if SPI-guided analgesia may offer advantages over the st and ard clinical practice . The study was design ed to evaluate if SPI-guided analgesia leads to a lower sympathetic modulation compared with st and ard clinical practice . METHODS  Electrocardiographic wave , non-invasive blood pressure and SPI  were recorded in ASA I-II patients undergoing elective laparoscopic cholecystectomy , r and omized to receive SPI-guided analgesia or st and ard analgesia .  Hemodynamic parameters , SPI , mean and variance of heart rate , low ( LF ) and high frequency ( HF ) spectral components of heart rate variability were measured at four time points : ( T0 ) baseline , ( T1 ) after induction of general anesthesia , ( T2 ) after pneumoperitoneum insufflation and ( T3 ) after pneumoperitoneum withdrawal . RESULTS SPI , hemodynamic and ANS parameters changed significantly in both groups during the study period ( P<0.0001 ) . At T2 SPI and markers of sympathetic modulation were significantly lower in SPI group ( mean [ SD ] SPI 38.1 [ 15.3 ] vs. 48.1 [ 16.2 ] normalized units , P<0.05 ; LF 38 [ 8.6 ] vs. 56.2 [ 20.6 ] normalized units , P<0.01 ; LF/HF 1.01 [ 1.1 ] vs. 2.68 [ 2.07 ] , P<0.01 ) . There was no difference in remifentanil consumption , recovery time from anesthesia , or postoperative pain and complications . CONCLUSION SPI-guided analgesia led to a more stable sympathetic modulation but did n't seem to offer clinical ly relevant advantages over the st and ard clinical practice for laparoscopic cholecystectomy Background : Surgical stress index ( SSI ) , a novel multivariate index , has recently been proven to react well to surgical nociceptive stimuli and analgesic drug concentration changes during general anesthesia . We investigated the feasibility of application of SSI for guidance of remifentanil administration during propofol – remifentanil anesthesia . Methods : Eighty patients scheduled for elective ear – nose – throat surgery were r and omized into two groups , SSI-guided analgesia group ( SSI group ) and st and ard practice analgesia group ( control group ) . In both groups , anesthesia was maintained with a propofol target-controlled infusion and adjusted stepwise by 0.5 & mgr;g/ml to keep bispectral index values between 40 and 60 . In the SSI group , the predicted effect-site concentration of remifentanil was adjusted stepwise by 1 ng/ml to keep SSI values between 20 and 50 , whereas in the control group , predicted effect-site concentration of remifentanil was adjusted according to traditional inadequate analgesia criteria . Anesthetics consumption , recovery times , and incidence of unwanted events were recorded . Results : Remifentanil consumption ( average normalized infusion rate ) was lower in the SSI group than in the control group ( mean ± SD , 9.5 ± 3.8 & mgr;g · kg−1 · h−1 vs. 12.3 ± 5.2 & mgr;g · kg−1 · h−1 ; P < 0.05 ) . The number of unwanted events was less in the SSI group ( 84 ) than in the control group ( 556 ; P < 0.01 ) . Recovery times were comparable between groups . No patient reported intraoperative recall . Conclusions : SSI-guided anesthesia result ed in lower remifentanil consumption , more stable hemodynamics , and a lower incidence of unwanted events BACKGROUND Autonomic nervous system ( ANS ) sensitively responds to intraoperative stress . Several indices characterizing the state and responses of autonomic signs to nociceptive stimuli have been introduced . This study evaluated the behaviour of ANS descriptors after induction , before and during tracheal intubation , and during bilateral tonsillectomies after r and om and blinded unilateral infiltration of lidocaine 1 % until emergence from anaesthesia . METHODS Twelve patients undergoing bilateral tonsillectomy  were anaesthetized with fentanyl and propofol ( induction ) and sevoflurane ( maintenance ) . All patients were monitored throughout anaesthesia for middle finger temperature , non-invasive arterial pressure , heart rate ( HR ) and pulse rate ( PR ) , state entropy ( SE ) and response entropy ( RE ) , and surgical pleth index ( SPI ) . New parameters complementing the above and characterizing the ANS state ( ANSS ) and responses are pulse-to-pulse interval ( PPI ) , pulse plethysmographic amplitude ( PPGA ) , ANSS , and an index based on maximal ANSS for the subject ( ANSSI ) . Serial data were stored as 10 s averages into a laptop computer . RESULTS Anaesthesia induction was associated with an increase in finger temperature to > 30 degrees C within 10 min , whereas PPGA increased to their maximum levels within 5 min . Laryngoscopy and intubation were associated with transient autonomic responses in most patients . All autonomic signs indicated statistically significant sympathetic activation during saline-infiltrated tonsillectomies when compared with lidocaine-infiltrated sides ( P<0001 ) . Hypnotic measures ( SE and RE ) and finger temperatures did not differ between the sides . CONCLUSIONS HR , PPI , PPGA , ANSS , ANSSI , SPI , and RE-SE detect autonomic responses to nociceptive stimuli and differentiate between tonsillectomies on locally anaesthetized tonsils from controls Being highly unstable , the critically ill polytrauma patient represents a challenge for the anaesthesia team . The aim of this study was to compare the Entropy and Surgical Pleth Index (SPI)—guided general anaesthesia with st and ard haemodynamic monitoring methods used in the critically ill polytrauma patients and to evaluate the incidence of hemodynamic events , as well as the opioid and vasopressor dem and .  72 patients were included in this prospect i ve observational study , divided in two groups , the ESPI Group ( N = 37 , patients that benefited from Entropy and SPI monitoring ) and the STDR Group ( N = 35 patients that benefited from st and ard hemodynamic monitoring ) . In the ESPI Group general anaesthesia was modulated in order to maintain the  Entropy levels between 40 and 60 . Analgesia control was achieved by maintaining the SPI levels between 20 and 50 . In the STDR Group hypnosis and analgesia were maintained using the st and ard criteria based on hemodynamic changes . Clinical Trials.gov identifier NCT03095430 . The incidence of hypotension episodes was significantly lower in the ESPI Group ( N = 3 ) , compared to the STDR Group ( N = 71 ) ( p < 0.05 ) . Moreover , the Fentanyl dem and was significantly lower in the ESPI Group ( p < 0.0001 , difference between means 5.000 ± 0.038 , 95 % confidence interval 4.9250–5.0750 ) , as well as vasopressor medication dem and ( p < 0.0001 , difference between means 0.960 ± 0.063 , 95 % confidence interval 0.8.334–1.0866 ) . The implementation of multimodal monitoring in the critically ill polytrauma patient brings substantial benefits both to the intraoperative clinical status and to the clinical outcome of these patients by reducing the incidence of anesthesia-related complications 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 aim ed 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 r and omly 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 ) BACKGROUND Monitoring of analgesia remains a challenge during general anaesthesia . The surgical stress index ( SSI ) is derived from the photoplethysmographic waveform amplitude and the heart beat-to-beat interval . We evaluated the ability of SSI to measure surgical stress in patients undergoing gynaecological laparoscopy . Our hypothesis was that while keeping State Entropy ( SE ) at a predetermined level , SSI would be higher in patients receiving a beta-blocking agent ( esmolol ) than in those receiving an opioid ( remifentanil ) during laparoscopy . METHODS Thirty women undergoing gynaecological laparoscopy were assigned r and omly to receive esmolol ( n = 15 ) or remifentanil ( n = 15 ) . Anaesthesia was induced with propofol and fentanyl and maintained with desflurane and nitrous oxide 50 % in oxygen to keep SE at 50(5 ) . The infusion of esmolol or remifentanil was started before laparoscopy and adjusted to keep the systolic blood pressure at -20 to + 10 % from the preoperative value . RESULTS During the fentanyl phase , before surgery , both groups behaved similarly , with an increase in SSI after intubation . In the patients receiving esmolol , the SSI reacted to the initial incision ( P < 0.05 ) , and remained high after trocar insertion ( P < 0.05 ) . In patients receiving remifentanil , it did not react to the initial incision , but increased after trocar insertion ( P < 0.05 ) , and it remained lower both after incision ( P < 0.05 ) and after trocar insertion ( P < 0.05 ) . CONCLUSION SSI was higher in patients receiving esmolol .  The index seems to reflect the level of surgical stress and may help guide the use of opioids during general anaesthesia 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 aim ed to investigate intravenous oxycodone consumption between SPI-guided analgesia and conventional analgesia practice s during sevoflurane anesthesia in patients undergoing thyroidectomy . Methods : Forty-five patients undergoing elective thyroidectomy were r and omly 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 
    Output:
    
No significant intergroup difference was observed in the pain score on the first postoperative day or the incidence of perioperative adverse events .
Conclusions Compared with conventional analgesia , SPI-guided analgesia can reduce intraoperative opioid consumption and facilitate extubation .
Moreover , no intergroup difference was observed in the degree of postoperative pain or incidence of perioperative adverse events