Propofol-remifentanil Group Research Articles

Efficacy and safety of ciprofol-remifentanil versus propofol-remifentanil during fiberoptic bronchoscopy: A prospective, randomized, double-blind, non-inferiority trial.

Objective: Ciprofol is a novel 2,6-disubstituted phenol derivative that has improved pharmacokinetic and pharmacodynamic properties compared with propofol. This study was conducted to compare the efficacy and safety of ciprofol-remifentanil versus propofol-remifentanil for patients undergoing fiberoptic bronchoscopy. Methods: Overall, 92 patients undergoing fiberoptic bronchoscopy were included in this prospective, randomized, double-blind, non-inferiority trial and were equally divided into two groups (n = 46 each). Fentanyl (50μg) was given 2min before the intravenous infusion of 0.3mg/kg of ciprofol or 1.2mg/kg of propofol over a time period of 30s. During anesthesia maintenance, 0.05-0.2μg/kg/min of remifentanil combined with one-third to one-fourth of the initial dose of ciprofol or propofol was repeated at 2-min intervals, as required, to maintain a Modified Observer's Assessment of Alertness and Sedation (MOAA/S) scale score <3. The primary outcome was the successful rate of fiberoptic bronchoscopy. Secondary outcomes included demographic characteristics, time metrics, hemodynamics, coughing severity, intubating conditions, lowest oxygen saturation, utilization of study drug doses, number of remedies (lidocaine and vasoactive drugs) used, satisfaction scores of both patients and the endoscopist, occurrence of intraoperative awareness, patients' willing to repeat fiberoptic bronchoscopy, and occurrence and severity of adverse events. Results: The successful completion rate of fiberoptic bronchoscopy was 91.30% (42 of 46; 95% confidence interval [CI]: 82.80%-99.80%) in the ciprofol-remifentanil group and 89.13% (41 of 46; 95% CI: 79.80%-98.50%) in the propofol-remifentanil group. Though the clinically acceptable intubating condition was improved in the ciprofol-remifentanil group, this difference has no clinical statistical difference (p > 0.05). No significant differences were noted between the two groups with respect to time metrics, consumption of fentanyl and remifentanil, or number of remedies (lidocaine and vasoactive drugs). Patients' willingness to repeat fiberoptic bronchoscopy and the satisfaction of both patients and endoscopist were significantly higher in the ciprofol-remifentanil than in the propofol-remifentanil group (p < 0.05). Compared with patients in the propofol-remifentanil group, patients in the ciprofol-remifentanil group had more stable hemodynamics. The lowest oxygen saturation was significantly higher in the ciprofol-remifentanil than in the propofol-remifentanil group (p < 0.05). The numbers of patients who experienced pain on injection in the ciprofol-remifentanil group was significantly lower than the number in the propofol-remifentanil group (p < 0.01). Severity of coughing, clinically acceptable severity of coughing, incidence of intraoperative awareness, and other adverse events were all similar between the two groups (p > 0.05). Only four patients experienced grade 2 adverse events (severe hypotension in one patient in the ciprofol-remifentanil group and three patients in the propofol-remifentanil group; p > 0.05); they were treated with noradrenaline. Conclusion: Ciprofol-remifentanil was non-inferior to propofol-remifentanil with regard to successful sedation for flexible bronchoscopy, when used with pre-intravenous administration of 50μg of fentanyl. At the same time, patients' willingness to repeat flexible bronchoscopy and the satisfactions were all significantly improved.

Comparison of Core Body Temperatures in Patients Administered Remimazolam or Propofol during Robotic-Assisted and Laparoscopic Radical Prostatectomy.

Background and Objectives: Different types of anesthetics affect thermoregulatory mechanisms, such as the redistribution of body temperature, loss of skin heat, or inhibition of thermoregulatory vasoconstriction. Therefore, we compared remimazolam with propofol in terms of core body temperature in patients undergoing robotic-assisted and laparoscopic radical prostatectomy. Materials and methods: Ninety patients were randomly assigned to either the propofol–remifentanil (PR) group or the remimazolam–remifentanil (RR) group. The PR group (n = 45) received effect-site concentrations of 6.0 μg/mL of propofol and 4 ng/mL of remifentanil, followed by 0.9 mg/kg of 1% rocuronium and maintenance with effect-site concentrations of 2–4 μg/mL of propofol and 3 ng/mL of remifentanil. The RR group (n = 45) received remimazolam 6 mg/kg/h by continuous intravenous infusion and the effect-site concentration of 4 ng/mL of remifentanil, followed by 0.9 mg/kg of 1% rocuronium, remimazolam 1–3 mg/kg/h, and remifentanil 3 ng/mL. The primary outcome was core body temperature, and secondary outcomes included vasoconstriction threshold (°C) and time to onset of vasoconstriction (min). Results: The core body temperature in the RR group was significantly higher at 60, 80, 100, 120, 140, 160, and 180 min after induction than in the PR group (p < 0.01). The vasoconstriction threshold was significantly higher in the RR group (35.2 ± 0.4) than in the PR group (34.8 ± 0.3) (p < 0.01). The time to onset of vasoconstriction was significantly less in the RR group (150.5 ± 10.2) than in the PR group (158.5 ± 8.4) (p < 0.01). However, the incidence of intraoperative hypothermia was not significant between two groups. Conclusions: Remimazolam appears to reduce vasoconstriction threshold less than and had a faster onset of vasoconstriction, resulting in superior thermoregulatory control.

Sevoflurane versus PRopofol combined with Remifentanil anesthesia Impact on postoperative Neurologic function in supratentorial Gliomas (SPRING): protocol for a randomized controlled trial

BackgroundPatients with intracranial tumors are more sensitive to anesthetics than the general population and are therefore more susceptible to postoperative neurologic and neurocognitive dysfunction. Sevoflurane or propofol combined with remifentanil are widely used general anesthetic regimens for craniotomy, with neither regimen shown to be superior to the other in terms of neuroprotective efficacy and anesthesia quality. There is no evidence regarding the variable effects on postoperative neurologic and neurocognitive functional outcome under these two general anesthetic regimens. This trial will compare inhalational sevoflurane or intravenous propofol combined with remifentanil anesthesia in patients with supratentorial gliomas and test the hypothesis that postoperative neurologic function is equally affected between the two regimens.MethodsThis is a prospective, single-center, randomized parallel arm equivalent clinical trial, which is approved by China Ethics Committee of Registering Clinical Trials (ChiECRCT-20,160,051). Patients with supratentorial gliomas diagnosed by magnetic resonance imaging will be eligible for the trial. Written informed consent will be obtained before randomly assigning each subject to either the sevoflurane-remifentanil or propofol-remifentanil group for anesthesia maintenance to achieve an equal-desired depth of anesthesia. Intraoperative intervention and monitoring will follow a standard anesthetic management protocol. All of the physiological parameters and other medications administered during the intervention will be recorded. The primary outcome will be neurologic function change assessed by National Institute of Health Stroke Scale (NIHSS) within 4 h after general anesthesia when observer’s assessment of alertness/sedation (OAA/S) reaches 4. Secondary outcomes will include NIHSS and modified NIHSS change 1 and 2 days after general anesthesia, hemodynamic stability, intraoperative brain relaxation, quality of anesthesia emergence, quality of anesthesia recovery, postoperative cognitive function, postoperative pain, postoperative neurologic complications, as well as perioperative medical expense.DiscussionThis randomized equivalency trial will primarily compare the impacts of sevoflurane-remifentanil and propofol-remifentanil anesthesia on short-term postoperative neurologic function in patients with supratentorial gliomas undergoing craniotomy. The exclusion criteria are strict to ensure that the groups are comparable in all aspects. Repeated and routine neurologic evaluations after operation are always important to evaluate neurosurgical patients’ recovery and any newly presenting complications. The results of this trial would help specifically to interpret anesthetic residual effects on postoperative outcomes, and perhaps would help the anesthesiologist to select the optimal anesthetic regimen to minimize its impact on neurologic function in this specific patient population.Trial registrationThe study was registered and approved by the Chinese Clinical Trial Registry (Chinese Clinical Trial Registry, ChiCTR-IOR-16009177). Principle investigator: Nan Lin (email address: linnan127@gmail.com) and Ruquan Han (email address: hanrq666@aliyun.com) Date of Registration: September 8th, 2016. Country of recruitment: China.

Comparison of surgical field visibility during propofol or desflurane anesthesia for middle ear microsurgery

BackgroundTo compare surgical field visibility between patients given propofol/remifentanil (PR) or desflurane/remifentanil (DR) anesthesia.MethodsA total of 80 adult patients undergoing middle ear microsurgery due to cholesteatoma otitis media with American Society of Anesthesiologists physical status I and II were randomly assigned to the PR or DR groups. The depth of anesthesia was titrated to maintain a Bispectral index (BIS) between 40 and 50. Remifentanil was titrated to maintain the mean blood pressure within ±30% change of the pre-induction value. Surgical field visibility was rated at several timepoints by the surgeons using the Boezaart scores.ResultsAverage Boezaart scores for surgical field visibility at different time points were < 2 in both PR and DR groups. Surgical field visibility score was lower in the PR group than in the DR group. Requirement for remifentanil was higher in the PR group (850 (488/1330) μg) than in the DR group (258 (143/399) μg, P < 0.0001). The site effect concentration of remifentanil was higher in the PR group (3.6(2.8/5.0)ng/ml) than in the DR group (1.7 (1.0/1.6) ng/ml, P < 0.0001). Hemodynamic profile (i.e., heart rate and mean blood pressure) was similar between groups (P > 0.05). Extubation time (PR group, 21 min vs. DR group, 19 min; P = 0.199) and post-anesthesia care unit time (PR group, 37 min vs. DR group, 34 min; P = 0.324) were comparable between groups.ConclusionAlthough PR anesthesia resulted in lower surgical field visibility scores than DR anesthesia, both groups had scores < 2, meaning no clinical differences between the two groups. DR provided acceptable operative conditions as well, albeit more remifentanil consumption was noted in the DR group.Trial registrationChina Clinical Research Information Service, ChiCTR-1,800,015,537. Registered 5 April 2018. Date of enrolment of the first participant to the trial: 2 May 2018.

Evaluation of volatile and intravenous anesthetics, effects on the threshold of neuroresponse telemetry and the threshold of acoustically evoked stapedial reflex in children undergoing cochlear implant surgery.

Background and Aims:Congenital hearing loss affects about 1 in every 1000 live births. Cochlear implant is an effective therapeutic method for aural rehabilitation in children suffering from severe-to-profound hearing loss. The aim of this study was to compare the effects of the intravenous and inhalational anesthesia techniques on neuroauditory threshold and stapedial reflex threshold responses.Material and Methods:After approval of the university ethics committee and obtaining written informed parental consent, 110 children with severe or profound bilateral sensorineural hearing loss undergoing cochlear implant surgery were randomly divided in two groups. The effects of the total intravenous anesthesia (propofol and remifentanil) and inhalation anesthesia (sevoflurane) techniques were evaluated on the neuroauditory threshold and stapedial reflex threshold responses of patients. Variations in systolic and diastolic blood pressures and mean arterial blood pressure were measured in both groups.Results:No significant difference was observed in the following parameters: age, weight, duration of anesthesia, and surgery. No side effects was observed in the two groups. No significant difference was found in the Telemetry Neuroal Response Test (TNRT) reflex between the two groups (P = 0.294); however, the difference between the two groups was significant (P = 0.001) for Electrical Stapedial Reflex Threshold (ESRT) reflex. In the sevoflurane group, in 39 patients in the electrode 3 and in 17 patients in the electrode 9 (compared with 20 and 6 patients in the Propofol–remifentanil group) complete suppression of stapedial reflex existed.Conclusion:Our results suggest that, during the cochlear implant surgery, use of inhalation anesthetics should be avoided for achieving controlled hypotension because this may suppress or even fully eliminate stapedial reflex. Remifentanil and Propofol infusion has a slight effect on hearing thresholds and is recommended for determining hearing thresholds during cochlear implant surgeries.

Comparison between propofol and propofol-remifentanil sedation under target-controlled infusion for impacted supernumerary teeth extraction surgery for children

Objective The aim of this study is to compare sedation titrated under target-controlled infusion of propofol and propofol-remifentanil for impacted supernumerary teeth extraction surgery for children. Methods A total of 60 children with anterior maxillary region impacted supernumerary teeth extraction surgery were divided randomly into two groups, namely, propofol group (group P, n=30) and propofol-remifentanil group (group PR, n=30). In group P, a titrated infusion of propofol was started until the modified observer's assessment of alertness/sedation (OAA/S) scale reached level 3 before the actual surgery. In group PR, a remifentanil infusion with a target plasma concentration of 1 ng·mL⁻¹ was started until the operation was finished. A titrated infusion of propofol was also started until the modified OAA/S score reached level 3 before the actual surgery. The Houpt behavior scale was adopted to evaluate the cooperation of each patient in both groups. The heart rate, blood pressure, respiratory rate, oxyhemoglobin saturation, and Narcotrend index, complications, adverse reactions and propofol infusion of all patients were recorded during the operation. Results The Houpt behavior scales in group PR were better than those in group P (P<0.05). The oxyhemoglobin saturation and respiratory rate in group PR were lower than that in group P (P<0.05). The heart rate, blood pressure and NI in two groups were no significant difference (P>0.05). The incidence of respiratory depression and anterograde amnesia in group PR were higher than that in group P (P<0.05). Conclusion Sedation titrated under the target-controlled infusion of propofol and that titrated under propofol-remifentanil for impacted supernumerary teeth extraction surgery for children are safe. The sedation titrated under target-controlled infusion of propofol-remifentanil is better than sedation by propofol when inhaling oxygen.

Impact of Dexmedetomidine on Intraoperative Wake-Up Tests in Patients Undergoing Spinal Surgery

To evaluate the impact of dexmedetomidine (DEX) on intraoperative wake-up tests. American Society of Anesthesiologists category I or II patients were divided into two groups: a propofol-remifentanil group (group R, n = 20) and a DEX-propofol-remifentanil group (group D, n = 20). The patients in group D received DEX, whereas the patients in group R received the same volume of saline. The other anesthetic methods and drugs (propofol and remifentanil) were the same in both groups. During the wake-up test, patients were repeatedly asked to move their fingers. All the wake-up tests were successfully performed. There was no significant difference in the mean wake-up time between the two groups. Eighteen patients exhibited better wake-up quality in group D as did eight patients in group R. The patients in group D had a significantly better overall wake-up quality than those in group R (P <.05). DEX did not affect the wake-up time and increased the wake-up quality.

Dexmedetomidine vs propofol-remifentanil conscious sedation for awake craniotomy: a prospective randomized controlled trial

BackgroundAwake craniotomy (AC) is performed for the resection of brain tumours in close proximity to areas of eloquent brain function to maximize reduction of tumour mass and minimize neurological injury. This study compares the efficacy and safety of dexmedetomidine vs propofol-remifentanil-based conscious sedation, during AC for supratentorial tumour resection. MethodsProspective, randomized, controlled trial including 50 adult patients undergoing AC who were randomly assigned to a dexmedetomidine (DEX group, n+25) or propofol-remifentanil group (P-R group, n+25). The primary outcome was the ability to perform intraoperative brain mapping assessed on a numeric rating scale (NRS). Secondary outcome was the efficacy of sedation measured by the modified Observer's Assessment of Alertness/Sedation (OAA/S) scale. Other outcome measures including haemodynamic and respiratory variables, pain, sedation and anxiety scores, adverse events, and patient satisfaction were also compared. ResultsThere were no differences between DEX and P-R groups regarding the ability to perform intraoperative brain mapping [mean NRS score (95% CI): 10.0 (9.9–10.0) vs 9.7 (9.5–10.0), P+0.13] and level of sedation during mapping [mean OAA/S score (95% CI): 4.1 (3.5–4.7) vs 4.3 (3.9–4.7), P+0.51], respectively. Respiratory adverse events were more frequent in the P-R group (20 vs 0%, P+0.021). Heart rate was significantly lower in the DEX group across time (P<0.001); however, the need for treatment of bradycardia was not different between groups. ConclusionsQuality of intraoperative brain mapping and efficacy of sedation with dexmedetomidine were similar to propofol-remifentanil during AC for supratentorial tumour resection. Dexmedetomidine was associated with fewer respiratory adverse events. Clinical trial registrationNCT01545297.

The influence of propofol and sevoflurane on intestinal motility during laparoscopic surgery.

Volatile anaesthetics have an influence on small bowel peristalsis during laparoscopic surgery. A recent study concluded that desflurane increased intestinal motility compared to sevoflurane. Hence, a desflurane-based anaesthesia protocol may reduce surgical exposure during intestinal suturing or stapling due to small bowel hyperperistalsis. The effect of propofol on intestinal motility is not well studied. We tested the hypothesis that a propofol-remifentanil anaesthesia increases intestinal contractions in comparison with a sevoflurane-remifentanil anaesthesia. Patients scheduled for laparoscopic gastric bypass surgery were randomized in this single blind randomized controlled trial to receive remifentanil combined with sevoflurane or propofol (ISRCTN 12921661). Bispectral index monitoring was used to guide depth of anaesthesia. Visual observation of peristaltic waves was performed during 1 min at the planned site of the jejunostomy. Statistical analysis was performed using Wilcoxon two-sample test. After obtaining written informed consent 50 patients were included. Groups were similar for demographic variables, and depth of anaesthesia during the observations. The median number of peristaltic waves was lower in the sevoflurane-remifentanil group compared to the propofol-remifentanil group (0 vs. 6, P < 0.001). Propofol-remifentanil increases intestinal motility compared with sevoflurane-remifentanil during laparoscopic gastric bypass surgery. A sevoflurane-based protocol can help to avoid disturbing peristalsis.

Effects of Different Anesthetics on Pain Processing in an Experimental Human Pain Model.

After surgical procedures, anesthesia itself may affect pain perception. Particularly, there is increasing evidence that opioids not only have analgesic effects but also provoke pronociceptive changes, that is, opioid-induced hyperalgesia. We investigated the effect of different anesthetic regimens on pain processing in volunteers using a transdermal electrical pain model. In this model, stimulation of epidermal nerve fibers representing mainly peptidergic C-nociceptors leads to secondary hyperalgesia and habituation to the stimulus. Forty-eight healthy volunteers underwent conditioning noxious stimulation (CS) over 5days. On day 2, the volunteers were randomized into 4 groups: control group (no anesthesia) and 3 groups receiving anesthesia before CS in anesthetic doses: propofol (P), propofol/remifentanil (PR), and propofol/remifentanil/S-ketamine (PRK). Quantitative sensory testing was performed on days 1 through 5 and on day 22. In every group, CS was associated with short- and long-term habituation to the electrical stimulus. Repetitive CS resulted in unmodified short-term sensitization with stable areas of hyperalgesia. Although the PR group showed a trend toward increased areas of hyperalgesia on day 2, no significant differences were detectable between the groups. In contrast, anesthesia resulted in decreased intensity of the electrically evoked pain on day 2. Finally, the mechanical pain threshold before CS on day 5 was increased in all groups and remained elevated 3weeks after the first CS, consistent with a long-term antinociceptive effect after CS. The results suggest a short-term analgesic effect of general anesthesia. Furthermore, the conditioning stimulation over several days induced differential modulation of pro- and antinociceptive systems.

Recovery from Anesthesia after Craniotomy for Supratentorial Tumors

Rapid recovery after supratentorial tumors (STT) removal is important. Short-acting anesthetics, such as propofol and remifentanil might favor this objective. The aim of this study was to compare the recovery of 2 Bispectral index (BIS)-guided anesthesia protocols combining sevoflurane-sufentanil (SS) or propofol-remifentanil (PR) administered during craniotomy for STT. After IRB approval and written consent, patients scheduled for surgical removal of STT were randomized to receive PR or SS. Anesthesia was adjusted to maintain BIS values between 45 and 55. The primary outcome was the time from discontinuation of anesthetics to extubation. Secondary endpoints were: time to respond to a simple order, and to achieve spontaneous ventilation, agitation score at emergence, postoperative Mini Mental State, postoperative Aldrete score, pain Visual Analogical Score, simplified sedation score, Glasgow Coma Scale, and surgical complications. Statistical analyses were performed using analysis of variance. Thirty-five and 31 were included in the SS and PR groups, respectively. Times to extubation was not different between the 2 groups (11.8±6.9 vs. 13.0±8.1 min in PR and SS groups, respectively, P=0.577). Although times to achieve an Aldrete score to 10, a Glasgow Coma Scale to 15, and a MMS to 30 significantly were lower in SS group, no significant difference was found when analyzing time course of these 3 factors over the first postoperative day. All other secondary endpoints were not different between the 2 groups. During craniotomy for STT, we could not demonstrate a reduction in the time to extubation when comparing a BIS-guided anesthesia associating PR to a BIS-guided anesthesia associating SS (Clinicatrials.gov identifier: NCT00389883).

Comparison of respiratory mechanics between sevoflurane and propofol-remifentanil anesthesia for laparoscopic colectomy

BackgroundThe creation of pneumoperitoneum and Trendelenburg positioning during laparoscopic surgery are associated with respiratory changes. We aimed to compare respiratory mechanics while using intravenous propofol and remifentanil vs. sevoflurane during laparoscopic colectomy.MethodsSixty patients undergoing laparoscopic colectomy were randomly allocated to one of the two groups: group PR (propofol-remifentanil group; n = 30), and group S (sevoflurane group; n = 30). Peak inspiratory pressure (PIP), dynamic lung compliance (Cdyn), and respiratory resistance (Rrs) values at five different time points: 5 minutes after induction of anesthesia (supine position, T1), 3 minutes after pneumoperitoneum (lithotomy position, T2), 3 minutes after pneumoperitoneum while in the lithotomy-Trendelenburg position (T3), 30 minutes after pneumoperitoneum (T4), and 3 minutes after deflation of pneumoperitoneum (T5).ResultsIn both groups, there were significant increases in PIP and Rrs while Cdyn decreased at times T2, T3, and T4 compared to T1 (P < 0.001). The Rrs of group PR for T2, T3, and T4 were significantly higher than those measured in group S for the corresponding time points (P < 0.05).ConclusionsRespiratory mechanics can be adversely affected during laparoscopic colectomy. Respiratory resistance was significantly higher during propofol-remifentanil anesthesia than sevoflurane anesthesia.

Effects of propofol versus sevoflurane combined with remifentanil anesthesia on activity of nuclear factor kappa B in neutrophil granulocyte during one-lung ventilation in patients undergoing radical resection of esophagus cancer

Objective To compare the effects of propofol versus sevoflurane combined with remifentanil anesthesia on the activity of nuclear factor-kappa B (NF-κB) in neutrophil granulocyte during one-lung ventilation (OLV) in patients undergoing radical resection of esophagus cancer.Methods Forty ASA physical status Ⅰ or Ⅱpatients of both sexes,aged 40-64 yr,with body mass index 18-25 kg/m2,undergoing radical resection of esophagus cancer,were randomized into 2 groups (n =20 each):propofol-remifentanil group (group P) and sevofluraneremifentanil group (group S).Anesthesia was induced with midazolam,sufentanil,etomidate and cisatracurium besylate in both groups.The patients were tracheal intubated and mechanically ventilated.Anesthesia was maintained with iv infusion of propofol 4-8 mg· kg-1 · min-1 in group P,or with inhalation of 1%-3% sevoflurane in group S,and with iv infusion of remifentanil 0.2μg· kg-1 · min-1 and intermittent iv boluses of cisatracurium besylate 7 mg in both groups.The Narcotrend index value was maintained between 40 and 50.Blood samples were taken from the radial artery at 5 min after intubation,the beginning of OLV,30,60 and 90 min of OLV,0 and 10 min after re-expansion of the collapsed lung,and the end of surgery for blood gas analysis and for determination of plasma concentrations of IL-1.The oxygenation index and respiratory index were calculated.The nuclear protein of neutrophil granulocytes was extracted for detection of NF-κB-DNA binding activity.Results Compared with group P,the respiratory index,plasma concentrations of IL-1 and NF-κB-DNA binding activity were significantly increased (P ＜ 0.05),and no significant change was found in the oxygenation index in group S (P ＞ 0.05).Conclusion Compared with sevoflurane-remifentanil anesthesia,propofol-remifentanil anesthesia can inhibit activation of NF-κB in neutrophil granulocyte and is helpful in attenuating the inflammatory response in lung tissues during OLV in patients undergoing radical resection of esophagus cancer. Key words: Propofol ; Anesthetics, inhalation ; Piperidines ; Respiration, artificial; NF-kappa B ; Neutrophils

Impact of stepwise hyperventilation on cerebral tissue oxygen saturation in anesthetized patients: a mechanistic study

While the decrease in blood carbon dioxide (CO2 ) secondary to hyperventilation is generally accepted to play a major role in the decrease of cerebral tissue oxygen saturation (SctO2 ), it remains unclear if the associated systemic hemodynamic changes are also accountable. Twenty-six patients (American Society of Anesthesiologists I-II) undergoing nonneurosurgical procedures were anesthetized with either propofol-remifentanil (n = 13) or sevoflurane (n = 13). During a stable intraoperative period, ventilation was adjusted stepwise from hypoventilation to hyperventilation to achieve a progressive change in end-tidal CO2 (ETCO2 ) from 55 to 25 mmHg. Minute ventilation, SctO2 , ETCO2 , mean arterial pressure (MAP), and cardiac output (CO) were recorded. Hyperventilation led to a SctO2 decrease from 78 ± 4% to 69 ± 5% (Δ = -9 ± 4%, P < 0.001) in the propofol-remifentanil group and from 81 ± 5% to 71 ± 7% (Δ = -10 ± 3%, P < 0.001) in the sevoflurane group. The decreases in SctO2 were not statistically different between these two groups (P = 0.5). SctO2 correlated significantly with ETCO2 in both groups (P < 0.001). SctO2 also correlated significantly with MAP (P < 0.001) and CO (P < 0.001) during propofol-remifentanil, but not sevoflurane (P = 0.4 and 0.5), anesthesia. The main mechanism responsible for the hyperventilation-induced decrease in SctO2 is hypocapnia during both propofol-remifentanil and sevoflurane anesthesia. Hyperventilation-associated increase in MAP and decrease in CO during propofol-remifentanil, but not sevoflurane, anesthesia may also contribute to the decrease in SctO2 but to a much smaller degree.

Post-Operative Effects: Comparison of Total Intravenous and Inhalational Anesthesia

Background: Propofol is an intravenous anesthetic with known antiemetic properties. Less confirmed are its potential analgesic or antinociceptive postoperative effects when used as a maintenance anesthetic during surgery. We compared the postoperative effects of total intravenous anesthesia (TIVA) with propofol to those of inhalational anesthesia with sevoflurane and looked for differences in the quality of recovery of patients. Methods: We studied 23 patients scheduled to undergo endoscopic sinus surgery (ESS). Using a doubleblind experimental method, we randomly assigned patients to receive either TIVA with propofol/remifentanil (PR) or inhalational anesthesia with sevoflurane/remifentanil (SR). We measured degree of pain (per visual analog scale where 1=no pain and 10=worst pain imaginable), incidence of nausea and vomiting, and duration of recovery postoperatively. Results: Mean pain rating was 3.4±3.3 in the PR group and 5.3±2.8 in the SR group. Median pain rating was 3±3 in the PR group and 5.5±1.5 in the SR group. In the PR group, 3 out of 12 patients reported a pain score > 4; In the SR group, 6 out of 10 patients reported a pain score > 4. Only 1 incidence of nausea was reported per group. Narcotics administered were comparable between both groups. Mean recovery time was 67±30 minutes in the PR group and 69±27 minutes in the SR group. Conclusion: We found no statistically significant difference between TIVA with propofol and inhalational anesthesia with sevoflurane as they relate to postoperative pain, nausea and vomiting, narcotic administration, and recovery time.

In Reply

We thank Drs. Moerman and De Hert for their interest and remarks on our article.1They provided a possible mechanism accounting for the discrepancy between cerebral oxygen saturation (SctO2) measured by near-infrared spectroscopy and jugular venous bulb oximetry (SjvO2). They also questioned the use of the standard Bland-Altman method to assess the agreement with repeated measures.It has been recently shown that propofol preserves cerebral oxygen saturation in the cortex through a region-specific alteration of the cerebral blood flow or cerebral metabolic rate of oxygen ratio.2In this context, Moerman and De Hert pointed out that propofol may preserve the cerebral oxygen saturation in the frontal cortex, which is the measurement site of near-infrared spectroscopy, thereby increase SctO2, resulting in comparable near-infrared spectroscopy values with those in the sevoflurane–nitrous oxide group. However, we ascribed the discrepancy between SctO2and SjvO2to the inherent limitations of the near-infrared spectroscopy technology. Moreover, the agreement between SctO2and SjvO2was not acceptable either in the sevoflurane–nitrous oxide or in the propofol–remifentanil group in our study, when assessed separately in each group. The inhomogeneous effect of propofol with an enhanced cerebral oxygenation in the frontal cortex may be responsible for the comparable SctO2in the two groups, but not the lack of agreement between the SctO2and SjvO2, if any.Moerman and De Hert also doubted whether Bland-Altman and linear regression analyses were applicable for repeated measures. We fully agree with them that standard Bland-Altman method may not be ideal for the repeated data. As such, we reanalyzed the data (SctO2against SjvO2) by using a Bland-Altman plot with multiple measurements per subject.3Nevertheless, we found little change in the 95% limit of agreement (from −37.8% to +23.6% with mean difference −7.2) compared with that (−38.2%, 23.8% with mean difference −7.2) of our previous data.1In fact, we used a Bland-Altman plot with multiple measurements per subject in another study and demonstrated a lack of agreement of SctO2and SjvO2values during the surgery in the beach chair position.4If we had used a modified rather than standard Bland-Altman method also in the current study,1the conclusion that SctO2may not be reliable in detecting a low SjvO2during the surgery in the beach chair position should remain the same.*Chonnam National University Medical School, Dong-gu, Gwangju, South Korea. kyyoo@jnu.ac.kr

Randomized double-blind study of remifentanil and dexmedetomidine for flexible bronchoscopy

The safety profiles and efficacies of remifentanil and dexmedetomidine (a sedative-analgesic without respiratory depression) for sedation during flexible bronchoscopy were investigated. Seventy-two patients undergoing elective flexible bronchoscopy were randomly assigned to a propofol-remifentanil group (Group PR, n=36) or a propofol-dexmedetomidine group (Group PD, n=36). The primary outcome was the incidence of oxygen desaturation. Haemodynamic variables, adverse events, need of oral cavity suction, cough scores, satisfaction scores of patients and bronchoscopists, levels of sedation, and recovery times were also compared. The incidence of oxygen desaturation was significantly lower in the PD group than in the PR group (P=0.01). There were no significant differences between groups in terms of level of sedation, oxygen saturation, mean arterial pressure, heart rate over time, cough scores, or patient satisfaction scores (P>0.05). However, cough scores and bronchoscopist satisfaction scores (P<0.01) were lower in the PD group. In addition, topical anaesthesia (P<0.01) was required more frequently and recovery time (P=0.00) was significantly longer in the PD group. However, oral suction (P=0.03) was required less frequently in the PD group. Dexmedetomidine was associated with fewer incidents of oxygen desaturation and a reduced need for oral cavity suction than remifentanil during flexible bronchoscopy. However, dexmedetomidine was associated with a longer recovery time and poorer bronchoscopist satisfaction score.

Effect of isoflurane versus propofol-remifentanil anesthesia on neuromuscular blockade and hemodynamic responses by cisatracurium bolus injection

BackgroundInhalational anesthetics potentiate nondepolarizing muscle relaxants. Cisatracurium is a recently introduced neuromuscular blocker in Korea. We studied the effect of inhalational anesthesia and total intravenous anesthesia (TIVA) on neuromuscular blockades and hemodynamic responses by cisatracurium bolus injection.MethodsForty patients undergoing elective surgery were randomly divided into isoflurane and propofol-remifentanil groups. A bolus dose of cisatracurium of 0.15 mg/kg (3 × ED95) was administered after induction and the onset time and clinical duration of action were recorded. The nueromuscular blockade was monitored using train-of-four (TOF) stimulation. Hemodynamic parameters were also recorded.ResultsOnset time was 194.0 ± 39.1 sec in the isoflurane group and 226.5 ± 62.2 sec in the propofol-remifentanil group. Clinical duration of action was 49.2 ± 9.0 min in the isoflurane group and 43.0 ± 9.2 min in the propofol-remifentanil group. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) immediately before intubation decreased in the propofol-remifentanil group. Heart rate (HR), SBP and DBP 1 and 3 min after tracheal intubation increased in the isoflurane group.ConclusionsOnset time was similar between isoflurane and propofol-remifentanil anesthesia. Clinical duration of action was significantly longer in isoflurane anesthesia. SBP and DBP immediately before intubation and HR, SBP and DBP 1 and 3 min after tracheal intubation were significantly different between the two groups.

Difference in Core temperature in response to propofol-remifentanil anesthesia and sevoflurane-remifentanil anesthesia

Hypothermia following the induction of anesthesia is caused by core to peripheral redistribution of body heat. It has been reported that propofol causes more severe hypothermia than sevoflurane by inhibiting thermoregulatory vasoconstriction during surgical procedures. Therefore, we evaluated the induction and maintenance of anesthesia with intravenous propofol to determine if it causes more core hypothermia than inhaled sevoflurane. Forty-five patients who underwent hysterectomy were divided into two groups randomly, a propofol-remifentanil (PR) anesthesia group and a sevoflurane-remifentanil (SR) anesthesia group. Each group was subjected to anesthetic induction with either 1.5 mg/kg propofol or inhalation of 5% sevoflurane, respectively. Anesthesia in the former group was maintained with propofol while it was maintained with sevoflurane in the latter group. Specifically, 6-10 mg/kg/hr propofol, 3 L/min medical air, 2 L/min O2, and 0.25 mg/kg/hr remifentanil were used in the PR group for maintenance, while 1.5 vol% sevoflurane, 3 L/min medical air, 2 L/min O2 and 0.25 mg/kg/hr remifentanil were used for maintenance in the SR group. We measured the core temperature 8 times, prior to induction and 10, 20, 30, 45, 60, 75 and 90 minutes after induction. Core temperatures decreased in both the PR and SR group during surgical operation, but there was no significant difference between the two groups. Anesthesia induced and maintained by propofol did not cause a greater degree of hypothermia than sevoflurane.

Anaesthesia for day case excisional breast biopsy

A randomized and prospective study was performed to compare anaesthetic characteristics and stress hormone responses of two anaesthetic techniques. Forty-two patients undergoing day case excisional biopsy of breast mass were randomly assigned to receive propofol-remifentanil or sevoflurane-N2O. Anaesthesia was induced and maintained either with sevoflurane and 50% N2O in oxygen or with target-controlled remifentanil and propofol in 50% oxygen and air. Anaesthetic depth was monitored by the bispectral index. The times for induction (2.9 vs. 1.7 min) and for laryngeal mask insertion (5.7 vs. 3.3 min) were longer in the sevoflurane-N2O group than in the propofol-remifentanil group. However, apnoea (57.1% vs. 9.5%) and bradycardia (23.8% vs. 0%) were more prevalent with propofol-remifentanil. In the sevoflurane-N2O group, the emergence times to a verbal response (10.6 vs. 3.7 min), to extubation (11.8 vs. 4.0 min) and to orientation (14.7 vs. 4.8 min) were longer than in the propofol-remifentanil group. There were significantly more nausea (38.1% vs. 4.8%) and vomiting (19.2% vs. 0%) in the sevoflurane-N2O group than in the propofol-remifentanil group. The time to discharge was similar although there was less postoperative pain in the sevoflurane-N2O group. There were no differences in the perioperative cortisol responses in the two groups. Smoother induction of anaesthesia was seen with sevoflurane-N2O. Propofol-remifentanil showed a quicker emergence with less nausea/vomiting. There were similar perioperative cortisol responses in the two anaesthetic techniques.