Administration of general anesthesia for outpatient orthognathic surgical procedures.

The administration of anesthesia has shifted away from the traditional hospital setting to an enormous increase in the use of outpatient facilities. The development of short-acting anesthetics, advances in surgical techniques, and paradigm shifts accepting targeted hospital admission and preoperative testing have allowed the acceptance of outpatient anesthesia for a wide variety of surgical procedures, including orthognathic procedures. Furthermore, the cost savings associated with office-based surgery and the declining insurance coverage for procedures such as orthognathic surgery have helped to increase the demand for surgery in this setting. The administration of anesthesia for orthognathic surgery in an outpatient setting requires preoperative preparation, preoperative patient assessment and selection, use of short-acting anesthetic agents and techniques, presence of emergency drugs and equipment, appropriate recovery protocols and staff, and the presence of adequate caregivers upon home discharge. Anesthetic techniques and agents allowing multiple orthognathic procedures to be performed in the outpatient setting are described.

[Resistance to vecuronium induced muscle relaxation in a patient with mental retardation receiving phenytoin for chronic anticonvulsant therapy].

A 36-year-old woman weighing 31.7 kg with mental retardation was scheduled for dental treatment under general anesthesia. She had undergone anticonvulsant therapy (phenytoin, clonazepam, zonisamide) for years. Standard monitors and bispectral index (BIS) monitor were applied except for an accelomyography. Anesthesia was induced with propofol and vecuronium, and maintained with nitrous oxide in oxygen, with 1.5-2.0% end-tidal concentration of sevoflurane. Forty minutes after induction of anesthesia, spontaneous respiration (SR) started suddenly despite adequate depth of anesthesia (BIS value 35-40). Vecuronium 1 mg was administered and SR stopped immediately. After the event, however, SR started repeatedly and then additional vecuronium was administered every 30-40 minutes to stop SR until the end of the treatment. During the treatment, no factors (hypercapnia, hypoxemia, hyperthermia and so on) to shorten the muscle relaxation were observed. The treatment finished uneventfully She became awake rapidly and extubated. Post-extubation period was also uneventful. In this case, chronic phenytoin therapy induced resistance to vecuronium was highly suspected; however, since clonazepam and zonisamide have elevation effects on blood concentration of phenytoin, they might be also cofactors in resistance to vecuronium. Therefore, patients undergoing chronic anticonvulsant therapy should be paid more attention because they have resistance to neuromuscular blocking drugs.

Rocuronium and vecuronium do not affect mandibular bone marrow and masseter muscular blood flow in rabbits.

PURPOSE: The goal of this study was to investigate the effect of rocuronium and vecuronium continuous infusion on oral tissue blood flow in rabbits. MATERIALS AND METHODS: We used 8 male Japan White rabbits. The infusion rates of rocuronium were 7, 14, and 28 microg kg(-1) min(-1) for 20 minutes, in this order. After rocuronium was discontinued and body movement confirmed, continuous infusion of vecuronium was started. The infusion rates of vecuronium were 1.6, 3.2, and 6.4 microg kg(-1) min(-1) for 20 minutes, in this order. Observed variables were systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, common carotid artery blood flow, tongue mucosal blood flow, oxygen partial pressure of the mandibular bone marrow, and oxygen partial pressure of the masseter muscle. RESULTS: Heart rate in both groups tended to decrease depending on the infusion rate. Common carotid artery blood flow in the rocuronium group was increased depending on the infusion rate. Tongue mucosal blood flow in the vecuronium group was decreased depending on the infusion rate. There were no differences in diastolic blood pressure, mean arterial pressure, oxygen partial pressure of the mandibular bone marrow, and oxygen partial pressure of the masseter muscle between the 2 groups. Systolic blood pressure in both groups showed no major change. CONCLUSION: Rocuronium and vecuronium did not change mandibular bone marrow and masseter muscular blood flows. Vecuronium decreased tongue mucosal blood flow depending on the infusion rate.

Monitoring masseter muscle evoked responses enables faster tracheal intubation.

PURPOSE: The aim of this study was to investigate whether monitoring neuromuscular block at the masseter muscle (MM) would allow faster tracheal intubation when compared with that at the adductor pollicis muscle (APM). METHODS: Twenty female patients undergoing gynecological surgery were enrolled into this study. Immediately after inducing anesthesia with fentanyl and propofol, both the left masseter and ulnar nerves were stimulated in a 2 Hz train-of-four (TOF) mode using peripheral nerve stimulators. Contractions of the MM were felt with the anesthesiologist's left hand lifting the patient's jaw and holding an anesthesia facemask, while those of the APM were visually observed. Immediately after the contracting responses of the muscles were confirmed, all of the patients received an iv bolus of vecuronium 0.1 mg kg(-1). Onset times after vecuronium were defined as the duration until the contractions became impalpable at the MM or invisible at the APM. When the contraction of the MM could no longer be felt, the conditions for laryngoscopy and tracheal intubation were assessed. RESULTS: Onset time evaluated tactually at the MM (mean +/- SD, 108.4 +/- 27.7 s) was significantly shorter than that evaluated visually at the APM (181.2 +/- 32.1 s, P < 0.0001). The intubating conditions for all patients were graded as either excellent or good. CONCLUSION: Tactual evaluation of muscle paralysis of the MM during induction of anesthesia is clinically useful since it leads to faster tracheal intubation.

Comparison of intubation condition and the quality of muscle relaxation between rocuronium and vecuronium using "timing principle".

Aim To compare the quality of the conditions for endotracheal intubation and muscle relaxation between rocuronium bromide and vecuronium bromide using the ''timing principle'' method for induction in anaesthesia. The "timing principle" includes the administration of muscle relaxants before the hypnotic agent during induction in anaesthesia. Method Sixty patients who had undergone elective surgery were randomly allocated into two equal groups using muscle relaxants: rocuronium (group R) and vecuronium (group V). The intubation conditions were assessed using Cooper's scoring system, based on jaw relaxation, vocal cords position and response to intubation. The quality of muscle relaxation was evaluated by recording the time of clinical weakness, a count of ''train of four'' (TOF) twitches at intubation, the time of loss TOF response and duration of direct laryngoscopy. Results The intubation conditions were excellent in 100% of patients in the group R versus excellent in 80% and good in 20% of patients in the group V (p<0.05). The time of clinical weakness was statistically significantly shorter in the group R than in the group V (p<0.000). The time of loss of TOF response was statistically significantly shorter in the group R (p<0.000). The absence of TOF twitches (the level of muscle relaxation of 100%) at intubation recorded in 25 (83.3%) patients in the group R versus five (16.7%) patients in the group V (p<0.000). Duration of direct laryngoscopy did not significantly differ between the groups. Conclusion Rocuronium bromide provides better intubation conditions and greater quality of muscle relaxation than vecuronium bromide using ''timing principle'' technique.

Involvement of the basal nucleus of Meynert on regional cerebral cortical vasodilation associated with masticatory muscle activity in rats.

We examined the neural mechanisms for increases in regional cerebral blood flow (rCBF) in the neocortex associated with mastication, focusing on the cortical vasodilative system derived from the nucleus basalis of Meynert (NBM). In pentobarbital-anesthetized rats, parietal cortical rCBF was recorded simultaneously with electromyogram (EMG) of jaw muscles, local field potentials of frontal cortex, multi-unit activity of NBM neurons, and systemic mean arterial pressure (MAP). When spontaneous rhythmic EMG activity was observed with cortical desynchronization, an increase in NBM activity and a marked rCBF increase independent of MAP changes were observed. A similar rCBF increase was elicited by repetitive electrical stimulation of unilateral cortical masticatory areas. The magnitude of rCBF increase was partially attenuated by administration of the GABAergic agonist muscimol into the NBM. The rCBF increase persisted after immobilization with systemic muscle relaxant (vecuronium). rCBF did not change when jaw muscle activity was induced by electrical stimulation of the pyramidal tract. The results suggest that activation of NBM vasodilator neurons contributes at least in part to the rCBF increase associated with masticatory muscle activity, and that the NBM activation is induced by central commands from the motor cortex, independently of feedback from brainstem central pattern generator or contracting muscles.

Safety and tolerability of single intravenous doses of sugammadex administered simultaneously with rocuronium or vecuronium in healthy volunteers.

BACKGROUND: Sugammadex rapidly reverses rocuronium- and vecuronium-induced neuromuscular block. To investigate the effect of combination of sugammadex and rocuronium or vecuronium on QT interval, it would be preferable to avoid the interference of anaesthesia. Therefore, this pilot study was performed to investigate the safety, tolerability, and plasma pharmacokinetics of single i.v. doses of sugammadex administered simultaneously with rocuronium or vecuronium to anaesthetized and non-anaesthetized healthy volunteers. METHODS: In this phase I study, 12 subjects were anaesthetized with propofol/remifentanil and received sugammadex 16, 20, or 32 mg kg(-1) combined with rocuronium 1.2 mg kg(-1) or vecuronium 0.1 mg kg(-1); four subjects were not anaesthetized and received sugammadex 32 mg kg(-1) with rocuronium 1.2 mg kg(-1) or vecuronium 0.1 mg kg(-1) (n=2 per treatment). Neuromuscular function was assessed by TOF-Watch SX monitoring in anaesthetized subjects and by clinical tests in non-anaesthetized volunteers. Sugammadex, rocuronium, and vecuronium plasma concentrations were measured at several time points. RESULTS: No serious adverse events (AEs) were reported. Fourteen subjects reported 23 AEs after study drug administration. Episodes of mild headache, tiredness, cold feeling (application site), dry mouth, oral discomfort, nausea, increased aspartate aminotransferase and gamma-glutamyltransferase levels, and moderate injection site irritation were considered as possibly related to the study drug. The ECG and vital signs showed no clinically relevant changes. Rocuronium/vecuronium plasma concentrations declined faster than those of sugammadex. CONCLUSIONS: Single-dose administration of sugammadex 16, 20, or 32 mg kg(-1) in combination with rocuronium 1.2 mg kg(-1) or vecuronium 0.1 mg kg(-1) was well tolerated with no clinical evidence of residual neuromuscular block, confirming that these combinations can safely be administered simultaneously to non-anaesthetized subjects. Rocuronium and vecuronium plasma concentrations decreased faster than those of sugammadex, reducing the theoretical risk of neuromuscular block developing over time.

The effect of d-tubocurarine priming on an ED95 dose of vecuronium bromide.

STUDY OBJECTIVE: To examine how priming with ED10 d-tubocurarine prior to the administration of ED95 vecuronium bromide affects onset and duration of neuromuscular blockade. DESIGN: Prospective, randomized, observer-blinded study. SETTING: Operating room at a university cancer center. PATIENTS: 40 ASA physical status I and II patients undergoing ambulatory surgical procedures. INTERVENTIONS: Patients were randomized to one of two groups. Group 1 patients received d-tubocurarine 50 micrograms/kg intravenously (IV), followed by vecuronium 60 micrograms/kg IV. Group 2 patients received vecuronium 60 micrograms/kg IV without priming. All patients received a total IV anesthetic consisting of alfentanil and propofol for induction of anesthesia and propofol alone for maintenance of anesthesia. MEASUREMENTS AND MAIN RESULTS: Onset of muscle relaxation was determined with an electromyograph (Datex Relaxograph), documenting time to 80% depression of the first twitch in a train-of-four (T(1)80%), percent depression of T1 at 60 and 90 seconds (T(1)60 and T(1)90, respectively), T4:T1 ratio at 90 seconds, and time to achieve maximal blockade (Bmax). Recovery was evaluated by measuring the time required for return of T1 to 25% of the baseline value. Intubating conditions were assessed at 90 seconds after vecuronium administration and graded on a 1 (jaw tight, impossible to intubate) to 4 (jaw relaxed, vocal cords immobile) scale. All criteria measuring onset of neuromuscular blockade (i.e., T(1)80%, T(1)60, T(1)90, T4:T1, and Bmax) were significantly shorter (p < 0.05) in patients who received d-tubocurarine. Recovery was similar in both groups. Intubation scores were significantly better 90 seconds after priming (p < 0.05). CONCLUSIONS: These results indicate that crossover dosing of nondepolarizing muscle relaxants may have synergistic effects. Priming with ED10 d-tubocurarine prior to an ED95 dose of vecuronium shortens the time to 80% T1 depression and produces satisfactory intubating conditions at 90 seconds, without prolonging the duration of the Therefore, d-tubocurarine is an attractive drug for priming vecuronium in short operative procedures that require muscle relaxation.

[Endotracheal intubation under propofol with or without vecuronium]. / Intubation endotrachéale sous propofol avec ou sans vécuronium.

OBJECTIVE: In order to test the hypothesis that under the association propofol-alfentanil-IV lidocaine the trachea could be intubated easily without an additional muscle relaxant, this study compared the intubation conditions when this association was combined or not with vecuronium. STUDY DESIGN: Randomized comparative trial. PATIENTS: The study included 152 young adults classified as ASA physical class I and Mallampati presentation grade 1, randomly allocated either into Vecu+ group or Vécu0 group, depending on whether vecuronium was co-administered or not. METHODS: All patients received midazolam 0.05 mg.kg-1 i.v., one minute before induction. Those of group Vecu0 were given successively within two minutes: alfentanil 0.03 mg.kg-1, lidocaine 1.5 mg.kg-1 i.v. and propofol 2.5 mg.kg-1. Patients of group Vecu+ received similar doses of alfentanil and propofol as well as vecuronium 0.08 mg.kg-1. The endotracheal tube was inserted one minute after induction in the patients of Vecu0 group, and after three minutes in those of the Vecu+ group. During intubation, scores of mouth opening, glottis opening and coughing were established, in order to assess intubation conditions. RESULTS: Similar convenient intubating conditions were obtained in both groups (in 97% of patients in Vecu+ group vs 95% of those in Vecu0 group). In the latter, the glottis opening was less pronounced. CONCLUSIONS: In young healthy adults, without anaesthetic risk (emergency, full stomach) and without foreseen difficult intubation, the endotracheal tube can be inserted in convenient conditions without a muscle relaxant, under the association propofol-alfentanil-lidocaine iv.

No effect of neuromuscular blockade on the temporomandibular joint position during general anesthesia.

In an attempt to determine the role that nondepolarizing neuromuscular blocking agents play in the intraoperative position of the mandibular condyle, occlusal checkbites were taken on 10 patients under general anesthesia before and after neuromuscular blockade with vecuronium. These checkbites were compared to checkbites taken preoperatively. Nondepolarizing neuromuscular blocking agents had no effect on condylar position recordings during general anesthesia. The results demonstrate that general anesthesia itself is by far the dominant factor in intraoperative condylar position changes.

Stability of vecuronium in sterile water for injection stored in polypropylene syringes for 21 days.

PURPOSE: The stability of vecuronium bromide 1 mg/mL in preservative-free sterile water for injection for up to 21 days was studied. METHODS: A vecuronium bromide 1-mg/mL solution was prepared by diluting 15 vials of 10-mg Vecuronium Bromide for Injection, USP, powder with preservative-free sterile water for injection and adding the solution to an evacuated i.v. bag. Identical 10-mL volumes of the solution were prepared and stored at 23-25 or 3-5 degrees C in polypropylene syringes. The stability of vecuronium was analyzed in triplicate with stability-indicating high-performance liquid chromatography immediately after preparation of solutions and at 3, 7, 14, and 21 days. The samples were also inspected for volume and color change and for visible precipitation and microbial growth. RESULTS: The percentage of the initial vecuronium bromide concentration remaining at each time point was greater than 100% at both 23-25 and 3-5 degrees C. There were no detectable changes in volume or color and no precipitation or visible microbial growth. CONCLUSION: Vecuronium bromide in an extemporaneously prepared solution in preservative-free sterile water for injection was stable for at least 21 days at 23-25 or 3-5 degrees C.

Anaphylaxis during anesthesia: results of a 12-year survey at a French pediatric center.

BACKGROUND: Following adverse reactions to anesthesia, tests are carried out to determine the mechanism of the reaction and to identify the agent responsible. No specific data are available in France concerning such skin tests in children. METHODS: Between 1989 and 2001, we assessed hypersensitivity reactions to general anesthesia in 68 children. Thirty underwent more than one operation, for congenital malformations. Immunoglobulin (Ig)E-mediated anaphylaxis was diagnosed on skin tests combined with the clinical history. RESULTS: Grade I, II and III reactions were observed in 20, 27 and 21 children, respectively. IgE-mediated anaphylaxis was diagnosed in 51 children: 31 (60.8%) for neuromuscular blocking agents (NMBA), 14 (27%) for latex, seven (14%) for colloids, five (9%) for opioids and six (12%) for hypnotics. Vecuronium was the NMBA causing the largest number of reactions. Cross reactivity to NMBA available in France was observed in 23 of 30 children (76%), particularly for vecuronium and atracurium or pancuronium. The estimated frequency of IgE mediated anaphylactic reactions was one in 2100 operations. Based on our results, 25 children subsequently received a different anesthetic with no adverse reaction. CONCLUSIONS: As in adults, NMBA, then latex were responsible for most anaphylactic reactions during anesthesia. Our results confirm that skin tests with anesthetic agents are feasible and safe in children and improve the safety of subsequent anesthetic procedures.

Effect of rate of injection on the neuromuscular block produced by vecuronium.

A subparalytic dose (0.015 mg/kg) of vecuronium bromide was administered to matched pairs of patients undergoing routine dental surgery under enflurane-nitrous oxide/oxygen anesthesia either as a rapid bolus injection or as a slow infusion over 5 min. It was demonstrated that bolus injection produced peak plasma levels of drug considerably greater than those following slow infusion. Time to maximum block was more rapid following bolus (368 +/- 84 [SD] sec) than by infusion (615 +/- 88 sec), but the maximum block produced, either demonstrated by the reduction in amplitude of T1 from control or the T1:T4 ratio on the integrated electromyogram (Datex IEMG), was similar in each group irrespective of rate of injection, T1 and T4 referring to the first and last twitch in a train of four series.

[The time-course of action of rapacuronium and mivacurium after early reversal following equally lasting relaxation]. / Spontane und induzierte neuromuskuläre Erholung nach gleich langer Relaxierung mit Rapacuronium und Mivacurium.

This study was designed to compare the time course of action and the safety profile of Rapacuronium and Mivacurium in day case dental surgery. After Ethics Committee approval 61 healthy adult patients, scheduled for dental day case surgery, were randomised in an assessor-blinded manner to receive either 1.5 mg/kg Rapacuronium with and without 0.05 neostigmine 5 min later (19 patients each) or a total of 0.25 mg/kg Mivacurium (n = 16). Anaesthesia was induced using Propofol 2 - 5.1 mg/kg and Remifentanil 24 - 73 mcg/kg/h and maintained with Desflurane in N2O/O2 (2/1). Endotracheal intubation was performed when maximum blockade was achieved and scored by a blinded intubator. Neuromuscular block was monitored using the train-of-four response to supramaximal stimuli at the ulnar nerve every 15 seconds using acceleromyography (TOF Watch SX). Onset time, clinical duration (reappearance of the third twitch of a TOF-stimulation) and recovery to T4/T1 > 0.9 were recorded. Speed of recovery was evaluated by the time difference between reappearance of the third twitch and T4/T1 > 0.9. The intubating conditions at the time of maximum block revealed no statistically significant differences between the three groups. Changes in blood pressure, heart rate and airway pressure were not significant. Onset time in subjects who received Rapacuronium (99 +/- 29 s) was faster compared to the onset time in those who received Mivacurium (157 +/- 36 s). Also clinical duration was significantly shorter following Rapacuronium without reversal (12 +/- 4 min) as well as with reversal (9 +/- 1 min) compared with Mivacurium (21 +/- 5 min)). Patients treated with Rapacuronium and reversal recovered faster (14 +/- 8 min)) compared to the other two groups (Mivacurium: 20 +/- 6 min, Rapacuronium without reversal: 31 +/- 9 min). The fraction of clinical duration of the total duration was highest following Mivacurium (51 %) when compared with Rapacuronium/Neostigmine (43 %) and Rapacuronium (28 %).

Alfentanil as an adjuvant of balanced anaesthesia for tonsillectomy in adults.

In a double-blind study, 80 adult patients, undergoing tonsillectomy, were randomly allocated to one of the four groups: d-tubocurarine (d-Tc) 50 micrograms/kg+alfentanil (Alf) 20 micrograms/kg, d-Tc 50 micrograms/kg+Alf 50 micrograms/kg, Alf 10 micrograms/kg+Alf 20 micrograms/kg, Alf 10 micrograms/kg+Alf 50 micrograms/kg. The first drug was given 2 min before thiopental and the second drug 1 min before inserting the mouth gag. Intubation was facilitated with suxamethonium. Anaesthesia was maintained with 70% nitrous oxide in oxygen and peripheral muscle relaxation during operation with vecuronium. For analysis of the induction characteristics, both d-Tc-pretreatment groups were treated together and compared with the results of the Alf-pretreatment groups. Muscle fasciculations occurred in 20% in the d-Tc group and in 70% in the Alf group. Neither d-tubocurarine nor alfentanil prevented the cardiovascular intubation response. Cardiovascular responses to the placement of the mouth gag occurred only in the lower-dose alfentanil groups. ECG changes during operation occurred in 25-45% of the patients. The most common ECG change was junctional rhythm. The operating conditions were good in 65-80% of the patients. The mean recovery score (0-10) ranged from 9.3 to 9.7 between the groups. The incidence of nausea ranged from 20-30% and that of vomiting from 10-25% between the groups. Bleeding from the operation site occurred in 20-30% of the patients. None of the patients needed sutures to stop the bleeding.

Pulmonary aspiration of gastric contents after a priming dose of vecuronium.

A case is presented of a 16-year-old girl with ectodermal dysplasia for whom dental surgery under general anaesthesia was planned. Following a priming dose of vecuronium, and immediately after injection of sodium thiopentone (5 mg.kg-1) pulmonary aspiration of gastric contents occurred. It is hypothesized that, because of the rapid speed of onset of neuromuscular blocking agents on the laryngeal muscles, that partial laryngeal paralysis was present at the time of induction of anaesthesia and that this was responsible in part for the episode of pulmonary aspiration.

Intraoperative vecuronium anaphylaxis compounded by latex hypersensitivity.

BACKGROUND: Anaphylaxis to latex or muscle relaxant drugs has been demonstrated in the perioperative period but there are no reports of a patient with anaphylaxis to both of these substances. METHODS: We report a patient with meningomyelocele who was initially thought to have anaphylaxis to latex during induction of anesthesia. After recurrence of anaphylaxis following removal of latex as the suspected agent, the muscle relaxant vecuronium was found to be the actual etiology. RESULTS: Skin testing to several muscle relaxants and other anesthetic medications confirmed a hypersensitivity to vecuronium. Skin testing and subsequent physical contact with latex also established a hypersensitivity to this substance. CONCLUSIONS: This report demonstrates the need to scrutinize closely every notation in the anesthesia record when evaluating perioperative anaphylaxis and to consider that hypersensitivity to more than one substance may be present.