James E. Fletcher

Tracheal extubation of deeply anesthetized pediatric patients: a comparison of desflurane and sevoflurane.

In this study, we examined the emergence characteristics of children tracheally extubated while deeply anesthetized with desflurane (Group D) or sevoflurane (Group S). Forty-eight children were randomly assigned to one of the two groups. At the end of the operation, all subjects were tracheally extubated while breathing 1.5 times the minimal effective concentration of assigned inhaled anesthetic. Recovery characteristics and complications were noted. Group D patients had higher arousal scores on arrival to the postanesthesia care unit than Group S patients. Later arousal scores were not significantly different. No serious complications occurred in either group. Coughing episodes and the overall incidence of complications after extubation were more frequent in Group D. Readiness for discharge and actual time to discharge were not significantly different between groups. Emergence agitation was common in both groups (33% overall, 46% for Group D, and 21% for Group S). Narcotic administration in the postanesthesia care unit occurred more frequently in Group D (10 of 24 patients) versus Group S (3 of 24 patients). Premedication with oral midazolam resulted in significantly longer emergence times regardless of the potent inhaled anesthetic administered.

Psychomotor performance after desflurane anesthesia: a comparison with isoflurane.

Recovery and psychomotor performance were studied in 80 ASA physical status I-III adult patients undergoing outpatient surgery. Patients were divided into four equal groups: thiopental induction of anesthesia followed by desflurane in nitrous oxide and oxygen (Th-DES-N2O/O2), thiopental induction of anesthesia followed by isoflurane in nitrous oxide and oxygen (Th-ISO-N2O/O2), thiopental induction of anesthesia followed by desflurane in oxygen (Th-DES-O2), and desflurane inhaled induction followed by desflurane in oxygen (DES-DES-O2). Patients were excluded from analysis if they required opioids or antiemetics postoperatively. The use of desflurane was associated with more rapid awakening compared with isoflurane (time to eye opening 9.45 +/- 0.67 min [Th-DES-N2O/O2] and 13.8 +/- 1.59 min [Th-ISO-N2O/O2], P less than 0.05). Psychomotor performance was measured using the choice reaction time and critical flicker fusion threshold. At 30 min after discontinuing anesthesia, five patients in the Th-ISO-N2O/O2 group and one patient in the Th-DES-N2O/O2 group were too sleepy to perform psychomotor tests. In addition, five patients who received Th-DES-O2 and one patient who received the inhaled induction and maintenance of anesthesia with desflurane in oxygen were too sleepy to perform tests at 30 min. Patients receiving Th-DES-N2O/O2 showed less impairment of choice reaction time than those receiving Th-ISO-N2O/O2. Critical flicker fusion threshold, however, showed no difference between groups. The use of thiopental was associated with delayed recovery. Compared with isoflurane, desflurane anesthesia is associated with more rapid initial awakening and less impairment of choice reaction time.

Methadone dosage for prevention of opioid withdrawal in children

Background Opioids are frequently used for sedation in the Paediatric Intensive Care Unit (PICU). With time the dosing often increases because of tolerance. On cessation of the sedation there is a risk of the opioid withdrawal syndrome. The aim of our study was to evaluate methadone dosing as a risk factor for opioid withdrawal and to determine optimal dose and efficacy of methadone to prevent withdrawal.

Fiberoptic-guided endotracheal intubation via the laryngeal mask airway in pediatric patients: a report of a series of cases.

The laryngeal mask airway is increasingly being used in pediatric anesthesia (1-3). The placement of the laryngeal mask airway in children results in an acceptable airway in more than 90% of patients (1) on the first attempt and in almost 100% on subsequent attempts. Experience in its use has increased to a degree where it is now being used for patients in whom airway management is difficult, with no untoward effects reported in previously published case reports (4-10). In some of these cases, the laryngeal mask airway has been used instead of endotracheal intubation (5,10), but this may not always be possible and an endotracheal tube may be required. There have been case reports of the laryngeal mask airway being used to facilitate endotracheal tube placement using guides such as catheters (4) or light stylets (6). These were placed blindly and hence had a risk of not being correctly positioned. The problem-free use of a fiberoptic bronchoscope through a laryngeal mask has been described for diagnostic bronchoscopy in children (7) ; it has also been used with a guide wire to assist endotracheal intubation (8). In our cases, we assessed a technique using a laryngeal mask airway to facilitate the use of a fiberoptic bronchoscope to position a guide wire under direct visualization for directing the placement of an endotracheal tube (Fig. 1). This technique allows for the maintenance of both oxygenation and inhalational anesthesia during the positioning of the bronchoscope via the laryngeal mask airway, up to the moment of passing the endotracheal tube over the guide wire.

Comparison of ocfentanil and fentanyl as supplements to general anesthesia

Three doses of ocfentanil (1, 3, and 5 μg/kg), a new narcotic, were compared with fentanyl (5 μg/kg) as a supplement to general anesthesia. Sixty adult ASA I-III patients undergoing elective surgery were studied. The drugs were given as a bolus injection during induction of anesthesia in a double-blind manner. With the stimulus of tracheal intubation, systolic arterial blood pressure increased (mean ± se) from 127 ± 6.9 to 183 ± 7.4 mm Hg and heart rate increased from 82.1 5 4.8 to 104 ± 6.4 beats/min in patients who had received 1 μg/kg of ocfentanil intravenously. In comparison to patients who received 1 & kg of ocfentanil, the increases in heart rate and systolic arterial blood pressure at the time of tracheal intubation were less with 3 and 5 μg/kg of ocfentanil and 5 μg/kg of fentanyl (P < 0.05). At incision, heart rate decreased after the intravenous administration of 5 μg/kg of ocfentanil when compared with patients who received 1 μg/kg of ocfentanil. There were differences between study groups in the mild increase in arterial blood pressure observed at incision. The authors conclude that ocfentanil and fentanyl appear to be similar in action, with 3 μg/kg of ocfentanil being approximately equivalent in effect to 5 μg/kg of fentanyl.

The effects of isoflurane and desflurane titrated to a bispectral index of 60 on the cortical somatosensory evoked potential during pediatric scoliosis surgery

In this study, we compared the effect of isoflurane and desflurane on the posterior tibial somatosensory evoked potential recorded by scalp electrodes during correction of idiopathic scoliosis in pediatric patients. Depth of sedation was controlled by maintaining bispectral index (BIS) at 60 throughout the study. Comparison of patients breathing desflurane and isoflurane showed an evoked cortical amplitude (N37-P45) of 0.53 ± 0.3 &mgr;V versus 1.3 ± 0.8 &mgr;V (P = 0.014), respectively. In addition to this comparison, a crossover design was included whereby the desflurane or isoflurane received in the first part of the study was changed to the other anesthetic. Substituting one anesthetic for another confirmed our initial finding that the cortical evoked amplitude is greater with isoflurane than with desflurane. No differential effect was found between desflurane and isoflurane on the evoked subcortical (N31-P34) amplitude or the P37 latency.

A report of the use of the Dynamic Objective Risk Assessment (DORA) score in the changing pediatric intensive care environment

OBJECTIVE To assess the clinical use of the Dynamic Objective Risk Assessment (DORA) severity of illness score in a site remote from its development. DESIGN Prospective chart review. SETTING Tertiary referral pediatric intensive care unit (PICU). PATIENTS One hundred sixty consecutive admissions involving 621 patient days. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Pediatric Risk of Mortality (PRISM) scores were collected daily for all PICU patient days. Collection of data was performed by a physician not directly involved in the ordering of vital signs or laboratory data. The daily DORA score was calculated from the previous days PRISM score and the admission PRISM score according to a previously described formula. The DORA score determines the patients risk of mortality for the next 24 hrs. Also documented were the tests not ordered for each patient day. The sensitivity and specificity of the DORA score in our patient population were very similar to that previously reported using the previously described 1% cutoff for predicted mortality. We also noted that the tests ordered were related to the physicians perception of the patients degree of sickness, and were themselves predictive of outcome. CONCLUSION An outcome scoring system created in one group of PICUs can be applied to patients in another PICU remote from where the scoring system was developed with similar ability to predict outcome.

Anaesthetic technique for transoesophageal echocardiography in children

Objective: To document the safety and efficacy of an anaesthetic technique in paediatric patients undergoing transoesophageal echocardiography (TOE).

The clinical effect of mixing different proportions of rocuronium and mivacurium.

Background : A synergistic effect has been described when rocuronium (Roc) and mivacurium (Miv) are combined in equal (i.e. 1 : 1) ED95 proportions at various total doses. We have investigated the effect of Roc or Miv alone and four different ratios (1 : 4, 2 : 3, 3 : 2 and 4 : 1) of Roc and Miv mixed to a total dose of 1.33 × ED95. The primary outcome is the ratio producing the maximum enhancement of duration of clinical effect.

An accidental ringblock of the great toe

An accidental ringblock of the great toe? SIRÐA 13-year-old, 27.5 kg male patient with arthrogryposis multiplex underwent an operative procedure for bilateral foot osteotomies, bilateral tendon lengthening, percutaneous heel cord lengthening, left metatarsal phalyngeal joint fusion and right great toe tendon transfer. General anaesthesia with iso ̄urane, nitrous oxide and fentanyl was used. A marked scoliosis prevented the use of an epidural for postoperative pain relief and so, at the end of the procedure, the patients wounds were in®ltrated with bupivacaine 0.25% with 1:200 000 epinephrine (27 ml), after which he was extubated and transferred to the recovery room. Within 30 min, it was noted that the right great toe had become blue and cold. The cast was cut without improvement, and a pulse oximeter applied to the toe did not register any pulsatile waveform. The patient did not complain of any pain from the ischaemic looking toe. The temporal relationship to the injection of epinephrine suggested that this was the cause of the vascular spasm. Apparently, the local anaesthetic and epinephrine solution had been able to track through the dissected tissue planes and come into contact with the terminal arteries supplying the great toe. Being pharmacologically appropriate and readily available, we chose to treat this complication by performing a ring block using phentolamine. Seven ml of phentolamine, 0.5 mgáml, was used to perform a ring block of the right great toe. Propofol, 30 mg, was used for sedation as the adjacent surgical sites remained painful. Within 3 min, the pulse oximeter detected a waveform and over the next hour the toe returned to a normal colour and warmth. The patient was observed in a high dependency unit overnight with no further problems. Accidental perivascular injection of epinephrine from the autoinjectors used to treat anaphylaxis at home have been described as causing severe ischaemia in the distal tissues, and have been successfully managed with phentolamine (1,2). However, a recent study of 100 patients, who received lidocaine 2% with epinephrine 1:80 000 for digital blocks showed only a mild reduction in distal blood ̄ow (3). This latter study is interesting because it uses a clinical dose of epinephrine, in contrast to the autoinjector accidents. Despite this latter observation, we have found that, even when local anaesthetic with epinephrine is injected at a site believed to remote from the terminal arteries of an extremity, that the drug may still track into an area that poses a risk to the patient. In this case, our dose of phentolamine proved to be an effective and safe treatment for vascular spasm caused by the epinephrine and prevented a potentially disastrous outcome.