The duration of residual neuromuscular block after administration of neostigmine or sugammadex at two visible twitches during train-of-four monitoring.

BACKGROUND: Adequate recovery from neuromuscular block (NMB) is imperative for the patient to have full control of pharyngeal and respiratory muscles. The train-of-4 (TOF) ratio should return to at least 0.90 to exclude potentially clinically significant postoperative residual block. Fade cannot be detected reliably with a peripheral nerve stimulator (PNS) at a TOF ratio >0.4. The time gap between loss of visual fade by using a PNS until objective TOF ratio has returned to >0.90 can be considered "the potentially unsafe period of recovery." According to our hypothesis the duration of this period would be significantly shorter with sugammadex than with neostigmine. METHODS: Fifty patients received volatile anesthetics, opioids, and a rocuronium-induced NMB. TOF-Watch without a preload was used, but the anesthesiologist relied on visual evaluation of the TOF responses only. At end of operation, patients were randomized to receive either neostigmine 50 µg/kg or sugammadex 2 mg/kg, when 2 twitch responses were detected after the last dose of rocuronium. Timing of tracheal extubation was based on PNS and clinical data. Duration of the potentially unsafe period of recovery after reversal by either neostigmine or sugammadex was analyzed. Mann-Whitney U test and Pearson χ(2) test were used for statistical analysis. RESULTS: The times [mean ± sd (range)] from loss of visual fade to TOF ratio >0.90 were 10.3 ± 5.5 (1.3 to 26.0) minutes and 0.3 ± 0.3 (0.0 to 1.0) minutes in the neostigmine and sugammadex groups, respectively (P < 0.001). The times from reversal by neostigmine or sugammadex to TOF ratio >0.90 were 13.3 ± 5.7 (3.5 to 28.9) and 1.7 ± 0.7 (0.7 to 3.5) minutes, respectively (P < 0.001). The values of TOF ratios at the time of loss of visual fade were 0.34 ± 0.14 (0.00 to 0.56) in patients given neostigmine and 0.86 ± 0.11 (0.64 to 1.04) in patients given sugammadex (P < 0.001). CONCLUSIONS: There is a significant time gap between visual loss of fade and return of TOF ratio >0.90 after reversal of a rocuronium block by neostigmine. Sugammadex in comparison with neostigmine allows a safer reversal of a moderate NMB when relying on visual evaluation of the TOF response.

Tubeless anaesthesia with sevoflurane and propofol in adult laryngeal surgery.

The presence of endotracheal intubation tube or jet ventilation cannula can compromise free view and access to operation area in certain endolaryngeal operations. The objective of this prospective study was to test whether adequate level of anaesthesia could be obtained in adults using tubeless sevoflurane inhalation anaesthesia with spontaneous breathing. In 23 ASA 1-2 patients, 31 treatments were included in the study of which 19 were laser-assisted papilloma or other tumour resections and 12 were fascia injection laryngoplasties. Anaesthesia was induced with propofol and maintained by insufflating sevoflurane mixture to the patient's oropharynx. The adequacy of the anaesthesia level was assessed by monitoring bispectral index, haemodynamic parameters and peripheral oxygen saturation during the anaesthesia. The ENT surgeon estimated operating conditions, whilst the two participating anaesthesiologists assessed the quality of anaesthesia using a 100 mm VAS scale. Sevoflurane contamination in the operating theatre was measured during five treatments. Mean bispectral index was below 40 throughout the operation. Haemodynamic parameters showed only minor changes during the anaesthesia. Both attending anaesthesiologists and operating ENT surgeon were satisfied with the quality of the anaesthesia and operating conditions (VAS 83 ± 15, mean ± SD, range 42-100, and VAS 93 ± 10, range 55-100, respectively). Sevoflurane room air contamination was high in most measured cases. The modification of tubeless inhalation anaesthesia used in this study produced adequate level of anaesthesia with stable haemodynamics and good operating conditions. Sevoflurane contamination can be reduced with more efficient scavenging systems.

Reversal of neuromuscular blockade by sugammadex does not affect EEG derived indices of depth of anesthesia.

OBJECTIVE: According to previous studies neuromuscular blockade may affect the depth of anesthesia. One theory states that neuromuscular blockade prevents disturbing EMG signals, arousing from the muscles of the forehead, from falsely elevating bispectral index (BIS)-levels. According to the afferentation theory signals generated in muscle stretch receptors, accessing the brain through afferent nerve pathways, induce arousal. By blocking these signals neuromuscular blockade would increase depth of anesthesia. Arousal has previously been associated with neostigmine reversal. This study investigates the possible effect of sugammadex on the level of anesthesia as defined by BIS and spectral entropy levels. METHODS: Thirty elective patients were enrolled. All patients received propofol and remifentanil by target controlled infusion and an intermediate level neuromuscular blockade induced and maintained by bolus doses of rocuronium. Depth of anesthesia was monitored by BIS and spectral entropy. The patients were given 2 mg/kg sugammadex 5 min after finishing of surgery. Propofol and remifentanil infusions were kept unchanged for another 10 min while BIS and entropy values were recorded. RESULTS: Mean BIS and Entropy™ values remained unchanged after reversal of the rocuronium block. The mean averaged BIS, state entropy and response entropy values were 31.7 ± 9.9, 35.3 ± 12.9 and 36.8 ± 13.3 before and 32.0 ± 11.9, 36.3 ± 15.9 and 38.4 ± 18.0 after sugammadex administration, respectively. CONCLUSIONS: Sugammadex does not affect level of anesthesia as determined by BIS or entropy levels.

Effect of nitrous oxide on cisatracurium infusion demands: a randomized controlled trial.

BACKGROUND: Recent studies have questioned our previous understanding on the effect of nitrous oxide on muscle relaxants, since nitrous oxide has been shown to potentiate the action of bolus doses of mivacurium, rocuronium and vecuronium. This study was aimed to investigate the possible effect of nitrous oxide on the infusion requirements of cisatracurium. METHODS: 70 ASA physical status I-III patients aged 18-75 years were enrolled in this randomized trial. The patients were undergoing elective surgery requiring general anesthesia with a duration of at least 90 minutes. Patients were randomized to receive propofol and remifentanil by target controlled infusion in combination with either a mixture of oxygen and nitrous oxide (Nitrous oxide/TIVA group) or oxygen in air (Air/TIVA group). A 0.1 mg/kg initial bolus of cisatracurium was administered before tracheal intubation, followed by a closed-loop computer controlled infusion of cisatracurium to produce and maintain a 90% neuromuscular block. Cumulative dose requirements of cisatracurium during the 90-min study period after bolus administration were measured and the asymptotic steady state rate of infusion to produce a constant 90% block was determined by applying nonlinear curve fitting to the data on the cumulative dose requirement during the study period. RESULTS: Controller performance, i.e. the ability of the controller to maintain neuromuscular block constant at the setpoint and patient characteristics were similar in both groups. The administration of nitrous oxide did not affect cisatracurium infusion requirements. The mean steady-state rates of infusion were 0.072 +/- 0.018 and 0.066 +/- 0.017 mg * kg-1 * h-1 in Air/TIVA and Nitrous oxide/TIVA groups, respectively. CONCLUSIONS: Nitrous oxide does not affect the infusion requirements of cisatracurium. TRIAL REGISTRATION: ClinicalTrials.gov NCT01152905; European Clinical Trials Database at http://eudract.emea.eu.int/2006-006037-41.

The effect of preoperative fasting on postoperative thirst, hunger and oral intake in paediatric ambulatory tonsillectomy.

AIMS AND OBJECTIVES: The aim of this prospective study was to examine whether preoperative face-to-face counselling about a child's fasting and active preoperative nutrition have an effect on thirst, hunger and postoperative oral intake in paediatric ambulatory tonsillectomy. Families, whose child was admitted for ambulatory tonsillectomy, participated in the study (n = 116; 58/58). BACKGROUND: Children undergoing tonsillectomy have difficulties in postoperative recovery and nutrition. However, former studies have shown that shorter preoperative fasting seems to promote postoperative well-being and promote the child's postoperative oral intake. DESIGN: A prospective, randomised intervention study. METHODS: The study groups were randomly allocated. The intervention group received the instructions through face-to-face counselling about the child's active preoperative nutrition, the control group received the instructions according to the current practice. The postoperative thirst and hunger were scored during the first postoperative hour and at two, four, eight and 24 hours postoperatively. The first scoring was performed by the nurse on a 0-10 scale. The rest of the estimations were made by the children using a visual analogue scale (VAS), by the parents using a 0-10 scale. RESULTS: In the intervention group, the VAS scores in thirst and hunger were low during the first 24 postoperative hours, whereas in the control group, they increased towards the following morning when the children in the control group, according to the children and the parents, were thirstier (p = 0.051, 0.005, respectively) and significantly hungrier (p = 0.042, 0.005) than those in the intervention group. CONCLUSIONS: Children's perioperative fluid fasting can be decreased with preoperative nutritional face-to-face counselling. Children's perioperative thirst and hunger can be relieved by the limited preoperative fasting. RELEVANCE TO CLINICAL PRACTICE: Clinical practice should take the child's perioperative fasting into account in a more accurate way in preoperative counselling of the parents.

The effect of preoperative nutritional face-to-face counseling about child's fasting on parental knowledge, preoperative need-for-information, and anxiety, in pediatric ambulatory tonsillectomy.

OBJECTIVE: The objective of this study was to define how preoperative nutritional face-to-face counseling on child's fasting affects parental knowledge, preoperative need-for-information, and anxiety, in pediatric ambulatory tonsillectomy. METHODS: The participants in the prospective, randomly allocated study were parents (intervention 62/control 62) with children (4-10 years) admitted for ambulatory tonsillectomy. Data were collected by the knowledge test designed for the study and with The Amsterdam preoperative anxiety and information scale (APAIS). The intervention group was invited to a preoperative visit to receive written and verbal face-to-face counseling. They were initiated into the child's active preoperative nutrition. The parents of the control group received current information without face-to-face counseling. RESULTS: The parents followed the instructions. Their knowledge about the child's fast increased (p=0.003), and need-for-information and anxiety decreased (p<0.0001) significantly. CONCLUSION: The preoperative face-to-face counseling with written information improves parental knowledge about the child's fasting and active preoperative nutrition, and relieves their need-for-information and anxiety. PRACTICE IMPLICATIONS: The primary responsibility remains with the health care professionals when the active preoperative nutrition of the child and counseling on it are introduced into nursing practice.

The effect of preoperative fasting on postoperative pain, nausea and vomiting in pediatric ambulatory tonsillectomy.

OBJECTIVE: The aim of this prospective randomized study was to examine whether active counseling and more liberal oral fluid intake decrease postoperative pain, nausea and vomiting in pediatric ambulatory tonsillectomy. METHODS: Families, whose child was admitted for ambulatory tonsillectomy or adenotonsillectomy, were randomly assigned to the study groups (n=116; 58 families in each group). The intervention group received the fasting instructions with face-to-face counseling for the child's active preoperative nutrition, and the control group the fasting instructions according to the hospital's standard procedure. The level of postoperative pain and nausea was scored in the postanesthesia care unit (PACU) during the first postoperative hour, as well as at 2, 4, 8 and 24h postoperatively. The first scoring in PACU was performed by the attending nurse with a 0-10 scale. The rest of the estimations were made independently and simultaneously by the children using a VAS scale, and by the parents using a 0-10 scale. RESULTS: The children in the control group were in more pain in the PACU than the children in the intervention group, and the difference between the groups was statistically significant (p=0.0002). All pain scores, according to the children and the parents, increased after the surgery. In both groups the highest score values were found at home 8h after surgery, and no significant difference was found between the study groups. On the first postoperative morning, the children in the control group were in pain (p=0.047). The children did not have significant nausea in the PACU, but the nausea increased postoperatively. Four hours after surgery the children were most nauseous according to all estimations (60%, n=116). More than half of the children vomited and most vomited clotted blood. Nausea and vomiting decreased during the evening of the surgery, but six children vomited the next morning, four of them vomited blood. The incidence and intensity of postoperative nausea and vomiting between the intervention and control groups were not statistically significant. However, preoperative nutritional counseling and more liberal per oral fluid intake appeared to have a positive effect on the children's well-being and helped them to better tolerate postoperative nausea and vomiting. CONCLUSIONS: The preoperative counseling about active preoperative nutrition significantly reduces the child's pain during the first posttonsillectomy hours and might prepare the child to better tolerate the stress of potential postoperative nausea and vomiting.

Quantitation of the effect of nitrous oxide on rocuronium infusion requirements using closed-loop feedback control.

BACKGROUND: Nitrous oxide has a minor effect on the effective dose 50% values of bolus doses of rocuronium. The authors have studied the effect of nitrous oxide on the infusion requirements of rocuronium using closed-loop feedback control of rocuronium infusion. METHODS: The authors obtained institutional approval and informed consent to study 70 patients. The patients were given total intravenous anesthesia with propofol and remifentanil by target-controlled infusion and were randomly assigned to one of two groups, one receiving nitrous oxide with 30% oxygen (n = 35) and the other group receiving air with 30% oxygen (n = 35). The possible interaction of rocuronium with nitrous oxide was quantitated by determining the asymptotic steady state rate of infusion of rocuronium necessary to produce a constant 90% neuromuscular block. This was accomplished by applying nonlinear curve fitting to data on the cumulative dose requirement during the initial 90-min period after bolus administration of rocuronium. RESULTS: Patient characteristics and controller performance, i.e., the ability of the controller to maintain the neuromuscular block constant at the set point, did not differ significantly between the groups. The administration of nitrous oxide did not affect rocuronium infusion requirements. The mean steady state rates of infusion were 33.0 +/- 9.8 and 36.9 +/- 13.2 mg/h in the nitrous oxide-total intravenous anesthesia and air-total intravenous anesthesia groups, respectively. CONCLUSIONS: Nitrous oxide does not affect the infusion requirements of rocuronium to a clinically significant degree.

Ketoprofen and tramadol for analgesia during early recovery after tonsillectomy in children.

BACKGROUND: Pain following tonsillectomy is often intense. Nonsteroidal anti-inflammatory drugs and opioids are effective, but both can cause adverse effects. Tramadol may be a viable alternative for post-tonsillectomy pain. This study was designed to compare the analgesic effects of ketoprofen and tramadol during the early recovery period after tonsillectomy. METHODS: Forty-five ASA class I children (9-15 years) were randomized to receive either saline, ketoprofen (2 mg.kg(-1)) or tramadol (1 mg.kg(-1)) after induction of anesthesia. Upon completion of surgery, the study treatment was continued as a 6 h intravenous (i.v.) infusion of another dose of saline, ketoprofen (2 mg.kg(-1)) or tramadol (1 mg.kg(-1)). Postoperatively, each patient received rescue analgesia with patient-controlled analgesia (PCA) device programmed to deliver 0.5 microg.kg(-1) bolus doses of fentanyl. Postoperative pain was assessed using Visual Analog Scale (VAS) during swallowing. Intraoperative blood loss was measured. RESULTS: The total number of requests of PCA-fentanyl was significantly less in ketoprofen group compared with tramadol and placebo groups (P = 0.035 and P = 0.049, respectively, in pairwise comparisons) and the VAS scores for pain were significantly lower in ketoprofen group compared with tramadol (P = 0.044) or placebo groups (P = 0.018) during the first six postoperative hours. Measured intraoperative blood loss was greater in ketoprofen-treated patients than in those receiving placebo (P = 0.029). CONCLUSION: A dose of 4 mg.kg(-1) of i.v. ketoprofen provided good pain relief with moderate supplemental PCA-fentanyl requirements during the first six postoperative hours after tonsillectomy in children whereas the effects of 2 mg.kg(-1) of i.v. tramadol did not differ from those of placebo.