Premedication before intubation in UK neonatal units.
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AIMS: To establish the extent and type of premedication used before intubation in neonatal units in the United Kingdom. METHODS: A structured telephone survey was conducted of 241 eligible units. Units were subdivided into those that routinely intubated and ventilated babies (routine group) and those that transferred intubated and ventilated babies (transfer group). RESULTS: Of the units contacted, 239 (99%) participated. Only 88/239 (37%) gave any sedation before intubating on the unit and only 34/239 (14%) had a written policy covering this. Morphine was used most commonly (66%), with other opioids and benzodiazepines used less frequently. Of the 88 units using sedation, 19 (22%) also used paralysis. Suxamethonium was given by 10/19 (53%) but only half of these combined it with atropine. Drug doses varied by factors of up to 200, even for commonly used drugs. CONCLUSION: Most UK neonatal units do not sedate babies before intubating, despite evidence of physiological and practical benefits. Only a minority have written guidelines, which prohibits auditing of practice. (+info)
Acoustic monitoring of intraoperative neuromuscular block.
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Standard methods for accurate intraoperative measurement of neuromuscular block are either expensive or inconvenient and are not used widely. We have evaluated a new method of monitoring neuromuscular block using a low-frequency microphone. The method is based on the phenomenon of low-frequency sound emission by contracting skeletal muscle. Acoustic monitoring (MIC) with an air-coupled microphone was used to evaluate intraoperative neuromuscular block in 25 anaesthetized patients. The MIC recorded the response of the adductor pollicis muscle to supramaximal electrical stimulation of the ulnar nerve with train-of-four stimuli. The ratios of the first response (TI) to control (TC) were used for evaluation. Data obtained from the MIC were compared with simultaneous recordings, from the same hand, of mechanomyography (FDT), electromyography (EMG) and accelerography (ACC). Throughout the operative procedure, TI/TC ratios of the acoustic method correlated with the three reference devices: FDT, 12 patients, 262 data sets, r = 0.86, bias (%MIC-%FDT) = mean -5.3 (SD 19.6)%; EMG, 18 patients, 490 data sets, r = 0.85, bias (%MIC-%EMG) = -0.39 (20.29)%; and ACC, 13 patients, 328 data sets, r = 0.91, bias (%MIC-%ACC) = -3.0 (15.6)%. We conclude that monitoring intraoperative neuromuscular block by a microphone which transduces low-frequency muscle sounds is clinically feasible. (+info)
Influence of neuromuscular block, mode of ventilation and respiratory cycle on pharyngeal mucosal pressures with the laryngeal mask airway.
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We tested the hypothesis that the pressure exerted by the laryngeal mask airway (LMA) against the pharyngeal mucosa varied with neuromuscular block, mode of ventilation and the respiratory cycle. We studied 20 anaesthetized adult patients. Microchip sensors were attached to a size 5 LMA at locations approximately corresponding to the base of the tongue, hypopharynx, lateral pharynx, oropharynx, posterior pharynx and piriform fossa. Mucosal pressures were measured with an intracuff pressure of 60 cm H2O under four conditions during anaesthesia using 2.0 MAC of sevoflurane: (1) apnoeic, non-paralysed; (2) spontaneously breathing, non-paralysed; (3) ventilated, paralysed and (4) non-ventilated, paralysed. In conditions (2) and (3), mucosal pressures were measured at the end of inspiration and expiration. Mean mucosal pressure was less than 10 cm H2O at all locations. There were no significant changes in mucosal pressure at any location between the four conditions. There was no variation between inspiration and expiration. With an intracuff pressure of 60 cm H2O in these circumstances, mucosal pressures were much less than considered safe for prolonged tracheal intubation. (+info)
Cisatracurium neuromuscular block at the adductor pollicis and the laryngeal adductor muscles in humans.
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We have compared the dose-response relationship (n = 30) and time course of neuromuscular block (n = 20) of cisatracurium at the laryngeal adductor and the adductor pollicis muscles. ED95 values for cisatracurium were 66.8 (95% confidence interval 61.3-72.3) micrograms kg-1 at the larynx and 45.2 (42.1-48.3) micrograms kg-1 at the adductor pollicis muscle (P < 0.0001). After administration of cisatracurium 0.1 mg kg-1, onset time was 2.7 (2.2-3.2) min at the larynx and 3.9 (3.0-4.8) min at the adductor pollicis (P < 0.0001). Time to 95% recovery of the first twitch of the TOF was 26.9 (20.1-33.7) min and 45.6 (39.7-51.5) min, respectively (P < 0.0001). We found that the laryngeal adductors were more resistant to the action of cisatracurium than the adductor pollicis muscle, but onset and recovery were faster at the larynx. (+info)
Response to vecuronium in a patient with facioscapulohumeral muscular dystrophy.
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Increased sensitivity to vecuronium has been noted in patients with Duchenne muscular dystrophy. We report the response to vecuronium in a patient with facioscapulohumeral muscular dystrophy (FSHD), an autosomal dominant disorder with an incidence of 10-20 cases per million. In this patient, sensitivity to an initial dose of vecuronium (0.02 + 0.08 mg kg-1) was normal, but recovery was faster and the effect of incremental doses of vecuronium (0.02 mg kg-1) was less than expected. Onset time and 25% recovery of T1/T0 after the intubating dose of vecuronium were 240 s and 22 min, respectively. Recovery index (spontaneous recovery of T1/T0 from 25% to 75%) was 9 min. (+info)
Comparison of intravenous or epidural patient-controlled analgesia in the elderly after major abdominal surgery.
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BACKGROUND: Patient-controlled analgesia (PCA) with intravenous morphine and patient-controlled epidural analgesia (PCEA), using an opioid either alone or in combination with a local anesthetic, are two major advances in the management of pain after major surgery. However, these techniques have been evaluated poorly in elderly people. This prospective, randomized study compared the effectiveness on postoperative pain and safety of PCEA and PCA after major abdominal surgery in the elderly patient. METHODS: Seventy patients older than 70 yr of age and undergoing major abdominal surgery were assigned randomly to receive either combined epidural analgesia and general anesthesia followed by postoperative PCEA, using a mixture of 0.125% bupivacaine and sufentanil (PCEA group), or general anesthesia followed by PCA with intravenous morphine (PCA group). Pain intensity was tested three times daily using a visual analog scale. Postoperative evaluation included mental status, cardiorespiratory and gastrointestinal functions, and patient satisfaction scores. RESULTS: Pain relief was better at rest (P = 0.001) and after coughing (P = 0.002) in the PCEA group during the 5 postoperative days. Satisfaction scores were better in the PCEA group. Although incidence of delirium was comparable in the PCA and PCEA groups (24% vs. 26%, respectively), mental status was improved on the fourth and fifth postoperative days in the PCEA group. The PCEA group recovered bowel function more quickly than did the PCA group. Cardiopulmonary complications were similar in the two groups. CONCLUSION: After major abdominal surgery in the elderly patient, patient-controlled analgesia, regardless of the route (epidural or parenteral), is effective. The epidural route using local anesthetics and an opioid provides better pain relief and improves mental status and bowel activity. (+info)
Rapacuronium for modified rapid sequence induction in elective caesarean section: neuromuscular blocking effects and safety compared with succinylcholine, and placental transfer.
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We have compared rapacuronium 2.5 mg kg-1 (n = 20) with succinylcholine 1.5 mg kg-1 (n = 22) in a multicentre, blinded, randomized study in full-term parturients undergoing elective Caesarean section under general anaesthesia. Thiopental 5 mg kg-1 was given i.v. followed by the neuromuscular blocking agent. Sixty seconds later intubation was performed. Intubating conditions, evaluated as excellent, good or poor, were good to excellent in 95% and 91% in the intent-to-treat patients after rapacuronium and succinylcholine, respectively (ns). Mean onset times at the adductor pollicis muscle for rapacuronium and succinylcholine were 80.4 (SEM 14.4) s and 63.9 (5.6) s (ns) while maximum block was 96 (1.9)% and 99 (0.4)%, respectively (ns). Rate of recovery was significantly longer after rapacuronium; times for return of T1 to 25% were 16.9 (1.5) min and 9.6 (1.1) min for rapacuronium and succinylcholine, respectively (P = 0.0004). Maternal side effects included more tachycardia and skin erythema with rapacuronium; no maternal mortality or morbidity, including bronchospasm, occurred in either group. There were no neonatal adverse effects in either group based on: Apgar scores at 1 and 5 min; times to sustained respiration; neuroadaptive capacity scores at 15 min, 2 h and 24 h; and umbilical venous and arterial blood-gas values and acid-base status. At delivery (17.7 (3.2) min), mean maternal plasma concentrations of rapacuronium were 9041.4 (1259.1) ng ml-1 and 506.4 (24.9) ng ml-1 for Org 9488 (the main metabolite). Corresponding values for umbilical venous plasma were 808.0 (92.1) ng ml-1 and 59.1 (6.5) ng ml-1, and for umbilical arterial plasma, 361.4 (56.4) ng ml-1 and 29.7 (4.6) ng ml-1, respectively. Umbilical venous to maternal venous ratios for rapacuronium and Org 9488 were 8.8% (1.3)% and 10.2 (1.7)%, respectively. (+info)
Acoustic reflectometry profiles of endotracheal and esophageal intubation.
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BACKGROUND: Acoustic reflectometry can be used to create a "one-dimensional image" of a cavity, such as the airway and lung, with the image displayed as an area-length curve. This pilot study was undertaken to determine whether acoustic reflectometry could be used to distinguish between an endotracheal and an esophageal intubation. METHODS: Ten adult patients underwent general endotracheal anesthesia and neuromuscular blockade. The reflectometer wavetube was attached to an endotracheal tube, and a reflectometric profile was obtained of the endotracheal tube and the airway and lung cavity. After confirmation of tracheal intubation, a second endotracheal tube was placed in the esophagus. After four breaths were administered, a reflectometric profile of the endotracheal tube-esophagus cavity was obtained. RESULTS: The acoustic reflectometric profiles for tracheal and esophageal intubation profiles were distinctive and characteristic. For an endotracheal tube-airway cavity, the profile shows a constant cross-sectional area throughout the length of the endotracheal tube, followed by a rapid rise in the area past the carina. For an esophageal intubation, the profile shows constant cross-sectional area throughout the length of the endotracheal tube, followed by a sudden decrease in the cross-sectional area to zero. CONCLUSIONS: In this pilot study, acoustic reflectometry within seconds, and without resort to capnography, was able to generate characteristic and distinctive area-length profiles for both endotracheal and esophageal intubation. Acoustic reflectometry may have a role in the emergency imaging of the airway, and in the immediate detection of esophageal intubations, particularly in cases of cardiopulmonary arrest in which the usual techniques for confirmation of breathing tube placement fail. (+info)