Low-dose Remifentanil Research Articles

Awake intubation and awake prone positioning of a morbidly obese patient for lumbar spine surgery

We describe the awake fibreoptic intubation followed by awake prone positioning of a woman weighing 180 kg with body mass index of 62 kg.m(-2) requiring emergency lumbar discectomy for cauda equina syndrome. This approach was taken to overcome difficulties in transfering an anaesthetised patient on to the operating table. Following topical anaesthesia with lidocaine and low-dose remifentanil infusion, oral intubation was performed using a split oral airway to guide the fibrescope. The patient positioned herself on the Jackson operating table, following which general anaesthesia was induced. This technique optimised protection of the patient's eyes and other pressure areas while preventing undue cardiorespiratory compromise. The patient tolerated the procedure well, and later confirmed that she would consent to undergoing the same procedure again if further surgery became necessary.

High-dose remifentanil prevents development of thermal hyperalgesia in a neuropathic pain model

Intraoperative nerve lesions can lead to chronic postoperative pain. There are conflicting data as to whether or not anaesthetics administered intraoperatively are beneficial. We investigated if remifentanil administered at the time of nerve injury was able to attenuate neuropathic hypersensitivity. Rats were anaesthetized with isoflurane, endotracheally intubated, and a tail vein catheter was inserted. Rats received an i.v. infusion of either saline or low- or high-dose remifentanil (2 or 20 μg kg(-1) min(-1), respectively) for 20 min. During this time, rats received a spinal nerve L5 transection to induce neuropathic pain or a sham procedure. Behavioural tests to assess mechanical and cold allodynia and heat hyperalgesia were performed on postoperative days 1, 3, 7, 14, 21, and 28. Sham-operated animals exhibited no hypersensitivity regardless of the intraoperative remifentanil dose. In rats which received spinal nerve L5 transection, mechanical and cold allodynia developed with no significant differences between treatment groups. However, thermal hyperalgesia was reduced in rats given high-dose remifentanil: mean (standard deviation) area under the curve 426 (53) compared with 363 (34) and 342 (24) in saline or low-dose remifentanil treated rats, respectively (P<0.05). High-dose remifentanil administered at the time of transection of the spinal nerve at L5 prevents subsequent thermal hyperalgesia.

Reducing the prevalence of chronic post-thoracotomy pain syndrome: is total intravenous anaesthesia superior to inhalation anaesthesia?

We read with great interest the article written by Song et al. [1]. The authors reported a prospectively randomized study, including 343 patients, regarding the effect of the type of anaesthesia on chronic post-thoracotomy pain syndrome (CPTS). They concluded that compared with inhalation anaesthesia, total intravenous anaethesia (TIVA) with propofol and remifentanil may reduce the incidence of CPTS. Their results are valuable, because the high incidence of CPTS after thoracic surgery is still a significant clinical problem. Although the pathophysiological mechanisms of CPTS after thoracic surgery remain unclear, neuropathic pain resulting from intercostal nerve injury seems to be the most important cause of CPTS. Patients with neuropathic pain, identified at 6 months postoperatively, have higher pain intensity and more analgesic consumption during the early postoperative period than other patients with pain [2]. The diagnosis of neuropathic pain depends on the combination of patients’ symptoms, intercostal nerve sensory testing and a DN4 neuropathic pain diagnostic questionnaire. In this study, however, the diagnostic pain is mainly dependent on patients’ oral description, lacking an objective assessment of neurophathic pain. At the early phase, 3 months and 6 months after thoracic surgery, both the pain intensity and the analgesic use did not show any difference between the TIVA group and the inhalation group, respectively. In addition, the incidence of the main pain characteristics between the two groups was not significantly different. Therefore, TIVA does not reduce the intensity of CPTS pain (including neuropathic pain), compared with inhalation anaesthesia. Moreover, TIVA plays a slight role in reducing the prevalence of CPTS (38.2% at 3 months and 33.5% at 6 months postoperatively), since the incidence of chronic pain complaints after thoracic surgery are reported as 25–60% previously [3]. More importantly, we find that the pain incidence at 6 months in the inhalation group (group II) in Table 3 (86/170) is inconsistent with the corresponding value in Table 4 (57/170). We do not know which is the correct figure regarding the number of patients with CPTS pain in the inhalation group. If the figures in Table 4 are correct, there would be a comparable incidence of the CPTS at 6 months postoperatively in both anaesthesia groups. Undoubtedly, multimodal analgesia during thoracic surgery can help prevent CPTS [4, 5]. As described in the article, pre-emptive analgesia, epidural analgesia combined with low-dose remifentanil and postoperative analgesic use in the TIVA group are all methods that have beneficial effects in preventing CPTS. In the inhalation group, however, only sevoflurane was used to maintain anaesthesia depth. In fact, due to its weak analgesic effect, we seldom use only inhale anaesthetics during thoracic surgery in clinical practice. And thus, the prevalence of CPTS (56.5% at 3 months and 50.6% at 6 months postoperatively) in the inhalation group is less significant clinically. If low-dose remifentanil is used in the inhalation group, as it is in the TIVA group, the incidence of CPTS in the inhalation group would probably decrease.

Remifentanil on the labour ward

The case report of remifentanil-induced respiratory arrest on the labour ward makes grim reading [1]. Remifentanil is not licensed for obstetric use. Indeed, the Summary of Product Characteristics clearly advises ‘The safety profile of remifentanil during labour or delivery has not been demonstrated. There are insufficient data to recommend remifentanil for use during labour and Caesarean section.’ In the case described, the patient’s weight is not given, and we are left to guess the dosage rate. Assuming a weight in the range 60–80 kg, the remifentanil dosage over 20 minutes is calculable between 0.18 and 0.23 μg.kg−1.min−1. In a rigorously conducted regulatory study, the ED50 for sedation in surgical patients was 0.043 μg.kg−1.min−1, and this was associated with ‘significant incidences of nausea, pruritus, sweating, and respiratory depression’ [2]. Because of these safety concerns, the development of low-dose remifentanil infusions as an adjunct sedative was abandoned. In a separate study, infusion of remifentanil at 0.1 ± 0.025 μg.kg−1.min−1 was effective for acute postoperative analgesia, although this practice has never become widespread, probably because of safety concerns [3]. The dosage received in this case therefore seems hefty. Advocates of remifentanil obstetric analgesia should not take comfort in personal series of such use of remifentanil without obvious complications. In the world of iatrogenic harm, ‘absence of evidence is not evidence of absence’ [4] and series of a few tens or hundreds of cases without disaster does not prove that a technique is safe [5]. Even if we disregard the basics of opioid pharmacology, anything that involves dissolving a powder, diluting the solution, setting up a pump, avoiding accidental boluses or siphoning, and concluding with the safe flushing of the cannula is far from foolproof. Safe practice, briefing, safety consciousness and protocols will attenuate, but not abolish, these risks. Finally, a pulse oximeter is not a monitor of respiration – but a capnograph is. Capnography via nasal ‘specs’ is now available for sedation monitoring and might have averted disaster if used in this case. As we currently lack trial data showing clinical benefit from remifentanil obstetric analgesia, it is difficult to see how its use can be justified. Must we press on until a young mother dies? [6].

The utility of bispectral index monitoring for sedated patients treated with low-dose remifentanil

The aim of the present study was to determine the effect of low-dose remifentanil on the monitoring quality of the Bispectral index for mechanically ventilated patients. Twelve patients who underwent elective surgery and required mechanical ventilation post-operatively were enrolled in this study with written informed consent. Eligible patients were divided into two groups. Patients in the remifentanil group received low-dose remifentanil (0.05-0.125 μg/kg/min) and propofol (1-3 mg/kg/h). Patients in the control group received propofol (1-3 mg/kg/h). Levels of sedation were evaluated by both the Richmond Agitation Sedation Scale (RASS) and BIS monitor (A2000-XP, version 4.0, Aspect Medical Systems, Newton, USA). Monitoring quality was assessed by a correlation between RASS and BIS values. These values were assessed by single regression analysis and a P value of <0.05 was considered significant. There was a significant correlation between RASS and BIS values (P = 3 × 10(-12), R (2) = 0.67) in the remifentanil group, but not in the control group (P = 0.50, R (2) = 0.057). The administration of low-dose remifentanil makes BIS a more precise tool for sedated patients under mechanical ventilation in the ICU.

Tracheal extubation of deeply anesthetized pediatric patients: a comparison of sevoflurane and sevoflurane in combination with low‐dose remifentanil

We aimed to observe the emergence characteristics of children tracheally extubated in deep anesthesia with sevoflurane or sevoflurane in combination with low-dose remifentanil. We randomly allocated 50 pediatric patients undergoing elective electronic cochlear implantation to groups either receiving sevoflurane (Group S, n = 25), or sevoflurane plus low-dose remifentanil (Group SR, n = 25), during extubation from anesthesia. In Group S, subjects were tracheally extubated while breathing 1.3 times the minimal effective concentration of sevoflurane. In Group SR, subjects were tracheally extubated while breathing 1.0 times the minimal effective concentration of sevoflurane with 0.02-0.05 μg · kg(-1) per min remifentanil. Recovery characteristics and airway complications were noted. There was no significant difference in age, weight, sex, and duration of anesthesia. The average remifentanil rate was 0.036 μg · kg(-1) per min, and compared with Group S, patients in Group SR had a lower respiratory rate (17.3 vs 20.2 per minute, P < 0.05) and a higher ETCO(2) (52.3 vs 49.4 mmHg, P < 0.05). Oral airway usage was also less frequent in Group SR (44% vs 16%, P < 0.01). Additionally, the time from extubation to spontaneous eye opening was shorter in Group SR (10.9 min vs 19.6 min, P < 0.01). Finally, six patients in Group S and five patients in Group SR had a pediatric anesthesia emergence delirium score >10. Low-dose remifentanil in combination with sevoflurane provided rapid recovery and was safe for deep tracheal extubation in deep anesthesia in pediatric patients.

Low-Dose Remifentanil Infusion during Ventilator Weaning and Tracheal Extubation in Postoperative Intensive Care Unit Patients Sedated with Propofol-Remifentanil: A Randomised Clinical Trial

Discontinuation of sedatives for ventilator weaning and extubation can be associated with hyperdynamic responses, including hypertension and tachycardia. We examined the effects of a maintained low dose of remifentanil infusion on cardiovascular responses and coughing during extubation in postoperative intensive care unit patients sedated with propofol-remifentanil. Fifty patients who required mechanical ventilation after major abdominal surgery were randomised into remifentanil group (n=25) or control group (n=25). Sedation during mechanical ventilation was maintained with remifentanil and propofol via a target-controlled infusion system. These drugs were titrated to the target sedation range, bispectral index values of 60 to 75 and Richmond Agitation Sedation Scale values of -3 to -2. When weaning was initiated, propofol was stopped in both groups. In the control group, remifentanil infusion was also stopped; in the remifentanil group, remifentanil infusion was maintained until extubation at a target effect site concentration of 1.0 ng/ml. Extubation was performed if the patient's respiratory, haemodynamic states were stable and if the patient was able to follow commands. Heart rate, mean arterial pressure and cough severity were evaluated. The mean arterial pressure, heart rate and cough severity did not differ between the two groups during extubation. The time from stopping of propofol infusion to extubation was significantly longer in the remifentanil group compared to that in the control group (P=0.020). Maintaining a low-dose remifentanil infusion during ventilator weaning, delayed tracheal extubation without any differences in haemodynamic changes or coughing in postoperative intensive care unit patients.

Effect of remifentanil on toll-like receptor 4, NF-κB and IL-6 in rabbit myocardial ischemia/reperfusion model

ObjectiveTo investigate whether remifentanil induced cardioprotecting effect is associated with expression of toll-like receptor 4 (TLR4), nuclear factorκB (NF-κB) and serum interleukin −6 (IL-6). MethodsFifty rabbits were randomly divided into 5 groups (n=10) according to the treatment: sham operation group (group A), ischemia-reperfusion group (group B), low-dose remifentanil group (group C), mediate-dose remifentanil group (group D), and high-dose remifentanil group (group E). Myocardial TLR4 mRNA levels, NF-κBprotein expression and serum levels of IL−6 were observed in 120 min after reperfusion. ResultsThe myocardial expressions of TLR4 mRNA, NF-κBprotein and IL-6 level in sera of groups B, C, D and E were elevated compared with group A. However, remifentanil significantly reduced the levels of TLR4 mRNA, NF-κB protein expression and serum IL-6 in groups C, D and E compared with group B. There were remarkable differences between the groups (P<0.01). ConclusionsIntravenous remifentanil has protective effect against rabbit myocardial ischemia/reperfusion injury. This effect may be associated with TLR4, NF-κB expressions on myocytes and serum level of IL-6 in a dose-dependent manner.

Ketamine, propofol and low dose remifentanil versus propofol and remifentanil for ERCP outside the operating room: Is ketamine not only a “rescue drug”?

SummaryBackgroundEndoscopic retrograde cholangiopancreatography ERCP is a painful and long procedure requiring transient deep analgesia and conscious sedation. An ideal anaesthetic that guarantees a rapid and smooth induction, good quality of maintenance, lack of adverse effects and rapid recovery is still lacking.This study aimed to compare safety and efficacy of a continuous infusion of low dose remifentanil plus ketamine combined with propofol in comparison to the standard regimen dose of remifentanil plus propofol continuous infusion during ERCP.Material/Methods322 ASAI-III patients, 18–85 years old and scheduled for planned ERCP were randomized. Exclusion criteria were a predictable difficult airway, drug allergy, and ASA IV–V patients.We evaluated Propofol 1 mg/kg/h plus Remifentanil 0.25 μg/kg/min (GR) vs. Propofol 1 mg/kg/h plus Ketamine 5 μg/kg/min and Remifentanil 0.1 μg/kg/min (GK).Main outcome measures were respiratory depression, nausea/vomiting, quality of intraoperative conditions, and discharge time. P≤0.05 was statistically significant (95% CI).ResultsRespiratory depression was observed in 25 patients in the GR group compared to 9 patients in the GK group (p=0.0035). ERCP was interrupted in 9 cases of GR vs. no cases in GK; patients ventilated without any complication. Mean discharge time was 20±5 min in GK and 35±6 min in GR (p=0.0078) and transfer to the ward delayed because of nausea and vomiting in 30 patients in GR vs. 5 patients in GK (p=0.0024). Quality of intraoperative conditions was rated highly satisfactory in 92% of GK vs. 67% of GR (p=0.028).ConclusionsThe drug combination used in GK confers clinical advantages because it avoids deep sedation, maintains adequate analgesia with conscious sedation, and achieves lower incidence of postprocedural nausea and vomiting with shorter discharge times.

Low-dose remifentanil to modify hemodynamic responses to tracheal intubation: comparison in normotensive and untreated/treated hypertensive Korean patients

BackgroundRemifentanil has been shown to be effective at treating potentially adverse hemodynamic responses to tracheal intubation even at low doses (< 1 µg/kg/min), which needs to be evaluated in patients with diverse cardiovascular conditions.MethodsA low-dose regimen of remifentanil (continuous infusion of 0.1 µg/kg/min, preceded by 0.5 µg/kg bolus) was given before induction with bolus propofol and rocuronium, and heart rate as well as systolic, diastolic, and mean arterial pressures were measured at 1 min intervals from before induction to 5 min after tracheal intubation in normotensive patients, untreated hypertensive patients, and patients with known hypertension.ResultsThe low-dose regimen of remifentanil resulted in parallel hemodynamic responses in all three groups, and was effective at limiting hemodynamic responses to tracheal intubation without excessive cardiovascular depression. Hemodynamic responses in our study showed a similar pattern to that reported in previous investigations, except for elevations in heart rate and arterial pressures over the baseline values immediately after intubation.ConclusionsWe suggest that the low-dose regimen of remifentanil in our study could be routinely used to modify hemodynamic responses to tracheal intubation in patients with diverse hemodynamic characteristics. However, the development of supplementary regimens is still needed to control the brief, but exaggerated responses to tracheal intubation, especially in untreated hypertensive patients.

Effects of remifentanil on lipid peroxidation during hemorrhagic shock-induced acute lung injury in rabbits

Objective To investigate the effects of remifentanil on lipid peroxidation druing hemorrhagic shock-induced acute lung injury （ALI） in rabbits. Methods Thirty-two healthy adult rabbits weighing 2.0-2.5 kg were randomly divided into 4 groups （n = 8 each）： sham operation group （group S）; ALI group; low-dose remifentanil group （group LR）; high-dose remifentanil group （group HR）. The left femoral artery was cannulated for blood-letting and blood sampling. The right femoral artery was cannulated for remifentanil administration. The model of hemorrhagic shock was established by modified Wigger＇ s methods. In group S, only cannulation was performed. In group LR and HR, remifentanil was infused intraperitoneally at 0.66 and 1.32 μg·kg-1 ·min-1 15 min before blood-letting respectively, while group ALI received equal volume of normal saline instead. Arterial blood samples were taken at 0, 20,70 and 100 min after blood-letting （T1-4） for blood gas analysis. The animals were then sacrificed and the lungs were immediately removed for histological examination with light microscope and determination of W/D lung weight ratio, MDA content and SOD activity. Results W/D ratio and MDA content were significantly increased, while SOD activity was significantly decreased in group ALI compared with group S （P 〈0.05）. The pH value at T2 and PaO2 at T2-4 in group LR and the pH value and PaCO2 at T2-4 in group HR were significantly higher than those in group ALI （P 〈 0.05）. W/D ratio and MDA content were significantly lower,while SOD activity was significantly higher in group LR and HR than in group ALI, and in group HR than in group LR （P 〈 0.05）. Remifentanil infusion significantly attenuated the pathologic changes in a dose-dependent manner. Conclusion Remifentanil pretreatment can attenuate hemorrhagic shock-induced ALI through inhibiting lipid peroxidation in rabbits. Key words: Piperidines; Respiratory distress syndrome,adult; Shock,hemorrhagic; Lipid peroxidation

Effects of remifentanil pretreatment on myocardial ischemia-reperfusion injury in rabbits

Objective To investigate the effects of remffentanil pretreatment on myocardial ischemiareperfusion (I/R) injury in rabbits. Methods Thirty healthy rabbits, aged 12-18 months, weighing 2.5-3.5 kg,were randomly divided into 3 groups (n = 10 each): I/R group, low-dose remifentanil pretreatment group (group R1 ) and high-dose remifentanil pretreatment group (group R2 ). Myocardial I/R was induced by ligation of anterior descending branch of left coronary artery for 30 min followed by 6 h of reperfusion in the 3 groups. Remifentanil was infused intavenously at 1.65 and 3.30 μg· kg - 1 · min- 1 for 30 min before ischemia in group R1 and R2 respectively, while equal volume of normal saline was infused instead in group I/R. Blood samples were taken for determination of serum cardiac troponin-Ⅰ (cTnI) and creatine kinase-MB isoenzyme (CK-MB) concentrations before administration (baseline), after administration, at 30 min of ischemia and at 6 h of reperfusion. The rabbits were then sacrificed and hearts removed. Myocardial tissues were obtained for microscopic examination. Results Serum cTnI and CK-MB concentrations were significantly lower in group R1 and R2 than in group I/R and serum cTnI concentration lower in group R2 than in group R1 ( P ＜ 0.01). Remifentanil infusion significantly attenuated the pathologic changes in a dose-dependent manner. Conclusion Remifentanil pretreatment provides protective effect against myocardial I/R injury in rabbits and it is related to the dose. Key words: Piperidines; Myocardial reperfusion injury

Perioperative management of an adult patient with childhood cerebral X-linked adrenoleukodystrophy

Perioperative management of an adult patient with childhood cerebral X-linked adrenoleukodystrophy

Different Anesthetic Techniques Associated with Different Incidences of Chronic Post-thoracotomy Pain: Low-Dose Remifentanil Plus Presurgical Epidural Analgesia is Preferable to High-Dose Remifentanil with Postsurgical Epidural Analgesia

To investigate the relationships between 2 anesthetic techniques, or the extent of allodynia around the surgical wound, and the occurrence of chronic post-thoracotomy pain. Prospective, randomized study. A single-institution, university hospital. Thirty-eight patients who underwent elective thoracotomy under general anesthesia. High-dose remifentanil (average effect-site concentration 5.61 +/- 0.84 ng/mL) with epidural analgesia started and at the end of surgery or low-dose remifentanil (average effect site concentration 1.99 +/- 0.02 ng/mL) with epidural analgesia with 0.5% ropivacaine started at the beginning of anesthesia. Pain intensity and the extent of allodynia around the wound were measured during the hospital stay. The presence and intensity of residual pain were assessed 1, 3, and 6 months after surgery and at the end of the study (6-13 months, average 9 months). A DN4 neuropathic pain diagnostic questionnaire was conducted at the same times. In the high-dose group, the area with allodynia was three times larger than the area in the low-dose group. The increased allodynia was associated with a higher incidence of chronic pain (RR: 2.7-4.2) 3 and 6 months after surgery and at the end of the study (median follow-up: 9.5 months). High-dose remifentanil (0.14-0.26 microg/kg/min) without epidural analgesia during surgery is associated with a large area of allodynia around the wound. These patients develop a much higher incidence of chronic pain than those receiving low-dose remifentanil with epidural analgesia during surgery.

Effects of Remifentanil on the Spectrum and Quantitative Parameters of Electroencephalogram in Propofol Anesthesia

A high dose of opioids associated with a low dose of propofol has become a popular anesthetic technique. However, the influence of opioids on the electroencephalographic phenomenon related to induction of anesthesia and, thereby, on the quantitative parameters used in the depth-of-anesthesia estimation is not well known. Twenty-seven patients were divided into three groups to receive saline, low-dose remifentanil (7.5 microg x kg x h) or high-dose remifentanil (30 microg x kg x h) during induction of anesthesia with propofol (30 mg . kg . h). Electroencephalogram was recorded from Fz electrode, and its time-frequency properties in the patient groups were analyzed from the induction of anesthesia to the occurrence of burst suppression pattern. The group differences in 14 quantitative spectral parameters used in the depth-of-anesthesia estimation were examined as well. The time-frequency properties of electroencephalogram were different between groups. The high-frequency (greater than 14 Hz) activity during light anesthesia was decreased in remifentanil groups; whereas, increased activity in extended alpha band (7-14 Hz) and decreased activity in delta band (0.5-4 Hz) was observed during deep anesthesia. This resulted in statistically significant changes in all 14 quantitative parameters. The effect of remifentanil on the spectrum and quantitative parameters of electroencephalogram is significant and strongly dependent on the level of anesthesia. Coadministration of opioids therefore challenges the reliability of the spectral properties of electroencephalogram in the depth-of-anesthesia estimation by using a frontal montage. Furthermore, the finding has implications for design of opioid coadministration studies.

The Art and Science of Propofol-Remifentanil Infusions for Office-Based Open Airway Anesthesia

This clinically-oriented presentation introduces the art of administering a propofol and low dose remifentanil admixture by microbolus and continuous infusion to achieve a dose-dependent choice of moderate sedation, deep sedation or general anesthesia. As midazolam has largely replaced diazepam, and propofol / methohexital; now remifentanil replaces fentanyl to segue a new era in the practice of anesthesia for the office-based, operator anesthetist. Current interest in this drug parallels similar phenomena witnessed in other countries. Long-standing and time honored “intermittent bolus techniques” with slower acting drugs will now be viewed as both cumbersome and obsolete.

The Effect of Low-Dose Remifentanil on Responses to the Endotracheal Tube During Emergence from General Anesthesia

Emergence from general anesthesia can be associated with coughing, agitation, and hemodynamic disturbances. Remifentanil may attenuate these responses. In a prospective, double-blind, randomized trial, we enrolled 60 adult patients undergoing nasal surgery using remifentanil-based anesthesia. During the emergence phase, the remifentanil group had remifentanil reduced to one tenth of the maintenance rate, whereas the control group had remifentanil discontinued. Times to awakening and tracheal extubation were similar between the two groups. During emergence, the remifentanil group (infusion rate 0.014 +/- 0.011 microg x kg(-1) x min(-1)) had a significantly lower incidence (40% vs 80%, P = 0.002) and less severe coughing compared with the control group, as well as a lower incidence of nonpurposeful movement (3.3% vs 30%, P = 0.006) and slower heart rates. Low-dose remifentanil during emergence did not prolong wake-up but reduced the incidence and severity of coughing from the endotracheal tube.

Remifentanil for percutaneous intravenous central catheter placement in preterm infant: a randomized controlled trial

There is limited evidence on the analgesic efficacy of opioids during percutaneous intravenous central catheter (PICC) insertion in preterm infants. To assess the analgesic and procedural efficacy of low-dose remifentanil infusion during PICC in preterm infants. Fifty-four neonates [mean gestational age (+/-sd) 28 +/- 2 weeks; birth weight 1126 +/- 337 g] were randomly assigned to remifentanil infusion at 0.03 mcg.kg(-1).min(-1) (R) or placebo (C) in addition to 0.3 ml of 12% sucrose per os and non-nutritive sucking. Validated pain scales [Neonatal Infants Pain Scale (NIPS) and Premature Infants Pain Profile (PIPP)] administered at the baseline T0, skin preparation T1, needle insertion T2, and recovery T3, revealed differences in mean NIPS scores (C 5.3 +/- 1.3 vs R 4.2 +/- 1.4 at T1 and C 5.0 +/- 1.3 vs R 3.4 +/- 1.3 at T2) and PIPP scores (C 9.3 +/- 1.6 vs R 7.1 +/- 1.5 at T1 and C 8.6 +/- 1.7 vs R 6.1 +/- 1.4 at T2); P < 0.05. Cardiovascular and respiratory response, and body movements during PICC suggested better pain and distress control with remifentanil (P < 0.05), but the time to complete the maneuver and the number of attempts needed remained the same in the two groups. Low-dose remifentanil has a measurable, synergic analgesic effect in combination with 12% sucrose and non-nutritive sucking, but does not make PICC easier or quicker.

Remifentanil for cesarean section under general anesthesia: effects on maternal stress hormone secretion and neonatal well-being: a randomized trial

Background Remifentanil may attenuate maternal hemodynamic response during cesarean section under general anesthesia, but could cause transient but significant neonatal depression. We investigated the effect of low-dose remifentanil on maternal neuroendocrine response and fetal wellbeing. Methods Forty-two ASA I-II parturients undergoing cesarean section at term under general anesthesia were randomized to receive either fentanyl after delivery (n = 21, group C) or remifentanil bolus 0.5 μg/kg before induction followed by a continuous infusion at 0.15 μg·kg −1min −1 until peritoneal incision, then restarted after delivery (n = 21, group R). Maternal heart rate and blood pressure, and epinephrine, norepinephrine, adrenocorticotropic hormone (ACTH), and growth hormone levels were measured at baseline, uterine incision, and the end of surgery. Remifentanil was measured in maternal and umbilical arterial and venous blood. One- and 5-minute Apgar scores and umbilical arterial and venous pH were recorded. Results ACTH was significantly higher in group C at uterine incision ( P < 0.01). No significant differences were observed in hemodynamics, catecholamines or growth hormone. Apgar scores at 1 ( P < 0.05) and 5 min ( P <0.01) were significantly higher in group C. Mean umbilical pH values were within normal range but significantly higher in group C. Three neonates in group R required intubation but recovered at 5 min without naloxone. Mean ± SD maternal remifentanil concentration was 1.67 ± 1.04 ng/mL. Conclusions Remifentanil administration before peritoneal incision partially reduced the hormonal stress response. Maternal benefits must be weighed against transitory but significant neonatal respiratory depression. Neonatal resuscitation facilities are mandatory when remifentanil is used.

Cannot ventilate, difficult to intubate

Reply EDITOR: The intention of reporting this case was to warn anaesthetists of the potential difficulties with airway management where the orbital floor has been removed, and therefore stimulate debate. We are pleased that Drs Chethan and Rassam and also Dr Massimiliano and colleagues have entered this debate. The patient did not initially have a prosthesis, simply a large dressing over the exenterated area. Concerning the preoperative evaluation, clearly in this case the ideal assessment would have been to carefully insert a fibreoptic scope under local anaesthesia into the orbital defect. It would then have been clear that the defect leads directly to the larynx and therefore that positive pressure ventilation via a facemask would not have been possible. Unfortunately this was not a practical option on the ophthalmic ward and, because of lack of accurate surgical information and a recent general anaesthetic in another hospital apparently without incident, was not considered. Limitation of mouth opening is a concern for the anaesthetist; however, it is not our practice to conduct an awake intubation unless the limitation is extreme. We would normally plan to use a McCoy laryngoscope with a bougie or consider the use of the Bullard laryngoscope, which can be used down to a mouth opening of 6 mm [1]. Awake fibreoptic intubation would be available but held in reserve. It is often the case, and it was so for this gentleman, that such patients return for further surgery. As it happens, between submission of the letter and publication, further general anaesthesia was required on two occasions. As Chethan and Rassam suggested, we placed an intubating laryngeal mask (size 5), and ventilated through the mask following the induction of anaesthesia. Although placement and ventilation was straightforward, successful intubation through the intubating laryngeal mask airway (ILMA) proved impossible both without and with fibreoptic assistance. This was abandoned and nasotracheal fibreoptic intubation was again successful. In retrospect, the difficulty with the ILMA probably related to the patient's airway anatomy, in that he is tall with a long neck. Thus the ILMA, although adequately positioned for ventilation, was not positioned optimally for successful endotracheal intubation. Using the Aintree catheter with the classic LMA would almost certainly have failed for the same reason. A subsequent successful general anaesthetic was achieved with an awake fibreoptic intubation with the aid of a low-dose remifentanil infusion. Total intravenous anaesthesia with infusions of propofol and remifentanil was used for maintenance of anaesthesia in each case. The major advantage of this technique was that further doses of muscle relaxants were not required, thus ensuring complete recovery from neuromuscular blockade after several hours of surgery, and once both anaesthetic agents had worn off, the patient was fully co-operative for controlled extubation without the risk of residual anaesthesia or paralysis.