View of the larynx obtained using the Miller blade and paraglossal approach, compared to that with the Macintosh blade.

The purpose of this study was to determine if laryngoscopy using a Miller blade with a paraglossal approach would yield an improved view of the larynx compared to that obtained with a Macintosh blade using the standard approach. One-hundred and sixty-one patients, scheduled for elective surgery requiring tracheal intubation, voluntarily participated in this study. Patients were randomly assigned to one of the two groups (Miller vs. Macintosh). A standard general anaesthetic was administered. Comparisons were made of the percentage of the vocal cords visible at laryngoscopy. The view of the airway was also graded using the Cormack and Lehane scale. Statistical analysis using Fisher's exact test was performed. A P value < 0.05 was considered statistically significant. The time required to complete intubation and complications if any, were also recorded. Laryngoscopy using the Miller blade allowed 100% of the vocal cords to be viewed in 78% of cases, whereas this was achievable in only 53% with the Macintosh blade (P = 0.0014). The Miller blade enabled greater than 25% of the vocal cords to be seen in 95% of the cases, whereas this was achievable in only 80% with the Macintosh laryngoscope (P = 0.003). A grade 1 Cormack and Lehane view of the larynx was obtained in 96.5% of cases in the Miller group compared with 85% in the Macintosh group (P = 0.02). Direct laryngoscopy using the Miller blade and paraglossal approach, afforded a much-improved view of the larynx in the majority of cases. For this reason trainees should learn laryngoscopy using both blades.

The attitude of the general public towards preoperative assessment and risks associated with general anesthesia.

PURPOSE: To survey the general public's attitude towards preoperative assessment and commonly perceived fears about general anesthesia. METHODS: A province wide telephone survey was conducted in Alberta. General and regional anesthesia were defined, a scenario involving major knee surgery was described, and participants were asked to choose between regional and general anesthesia. Respondents used a seven-point scale to rate the importance of seeing an anesthesiologist preoperatively and were questioned about the timing of such a visit. Attitudes towards commonly perceived fears associated with anesthesia were also assessed. RESULTS: A total of 1,216 people were surveyed. Over 30% of respondents felt that it was very important to see an anesthesiologist preoperatively, with a total of over 60% attributing a high degree of importance to this. Fifty percent felt that this assessment should occur on the day prior to surgery. A preference for regional or general anesthesia was not expressed in the situation. Approximately 20% of respondents were very concerned about brain damage, waking up intraoperatively and memory loss. Twelve percent were concerned about dying intraoperatively. Nine percent expressed concern about postoperative pain, with 12% reporting being concerned about nausea and vomiting. CONCLUSIONS: The general public considers anesthetic assessment on the day prior to surgery an important part of preoperative preparation. Fears of brain damage, death and intraoperative awareness associated with general anesthesia remain prevalent, suggesting that preoperative education of patients should address these concerns. The general population was less concerned about realistic fears such as nausea, vomiting and postoperative discomfort.

Complications of regional anaesthesia Incidence and prevention.

The complications of failure, neural injury and local anaesthetic toxicity are common to all regional anaesthesia techniques, and individual techniques are associated with specific complications. All potential candidates for regional anaesthesia should be thoroughly evaluated and informed of potential complications. If there is significant risk of injury, then these techniques should be avoided. Central neural blockade (CNB) still accounts for more than 70% of regional anaesthesia procedures. Permanent neurological injury is rare (0.02 to 0.07%); however, transient injuries do occur and are more common (0.01 to 0.8%). Pain on injection and paraesthesiae while performing regional anaesthesia are danger signals of potential injury and must not be ignored. The incidence of systemic toxicity to local anaesthetics has significantly reduced in the past 30 years, from 0.2 to 0.01%. Peripheral nerve blocks are associated with the highest incidence of systemic toxicity (7.5 per 10000) and the lowest incidence of serious neural injury (1.9 per 10000). Intravenous regional anaesthesia is one of the safest and most reliable forms of regional anaesthesia for short procedures on the upper extremity. Brachial plexus anaesthesia is one of the most challenging procedures. Axillary blocks are performed most frequently and are safer than supraclavicular approaches. Ophthalmic surgery is particularly suited to regional anaesthesia. Serious risks include retrobulbar haemorrhage, brain stem anaesthesia and globe perforation, but are uncommon with skilled practitioners. Postdural puncture headache remains a common complication of epidural and spinal anaesthesia; however, the incidence has decreased significantly in the past 2 to 3 decades from 37 to approximately 1%, largely because of advances in needle design. Backache is frequently linked with CNB; however, other causes should also be considered. Duration of surgery, irrespective of the anaesthetic technique, seems to be the most important factor. The syndrome of transient neurological symptoms is a form of backache that is associated with patient position and use of lidocaine (lignocaine). Disturbances of micturition are a common accompaniment of CNB, especially in elderly males. Hypotension is the most common cardiovascular disturbance associated with CNB. Severe bradycardia and even cardiac arrest have been reported in healthy patients following neuraxial anaesthesia, with a reported incidence of cardiac arrest of 6.4 per 10 000 associated with spinal anaesthesia. Prompt diagnosis, immediate cardiopulmonary resuscitation and aggressive vasopressor therapy with epinephrine (adrenaline) are required. New complications of regional anaesthesia emerge occasionally, e.g. cauda equina syndrome with chloroprocaine, microspinal catheters and 5% hyperbaric lidocaine, and epidural haematoma formation in association with low molecular weight heparin. Even so, after 100 years of experience, most discerning physicians appreciate the benefits of regional anaesthesia.

Prolonged epidural infusions of ropivacaine (2 mg/mL) after colonic surgery: the impact of adding fentanyl.

UNLABELLED: We evaluated the safety and efficacy of a 72-h epidural infusion of ropivacaine and measured the impact of adding fentanyl 2 microg/mL to the required infusion rate, on the quality of postoperative pain relief and the incidence of side effects, after colonic surgery. One hundred fifty-five patients scheduled for elective colonic surgery were randomized in this trial. Epidural infusions of ropivacaine 2 mg/mL with fentanyl 2 microg/mL (R + F) and without fentanyl (R) were commenced during surgery and continued for 72 h postoperatively. This was a prospective, randomized, double-blinded, multi-center trial. The median infusion rate required was less in the R + F group (9.3 vs 11.5 mL/h, P < 0.001). Median pain scores at rest and on coughing were lower in the R + F group (P < 0.0001). The incidence of hypotension was more in the R + F group (P = 0.01). Time to readiness for discharge was delayed in the R + F group (median 6.6 vs 5.5 days, P = 0.012). The addition of fentanyl to ropivacaine resulted in decreased infusion rates and enhanced pain control; however, adverse effects were increased and readiness to discharge was delayed. IMPLICATIONS: Epidural infusions of ropivacaine with and without fentanyl were administered to patients to control pain after colonic surgery. Patients who received ropivacaine with fentanyl had better pain control, increased side effects, and delayed readiness to discharge. This study questions the value of adding opioids to epidural infusions of local anesthetics.

Thoracic epidural anesthesia for bilateral reduction mammoplasty in a patient with Klippel-Feil syndrome.

General anesthesia is best avoided in cases of Klippel-Feil syndrome where tracheal intubation is potentially difficult. The syndrome features severe abnormalities of the neck and upper thoracic spine, which may also lead to difficulties with neuraxial blockade. We describe the use of epidural anesthesia for bilateral reduction mammoplasty in a patient with this condition.

Recent Advances in Brachial Plexus Anesthesia: a Review

Avances recientes en la anestesia del Plexo Braquial. La anestesia del plexo braquial a estado en boga por más de 80 años. De todas las técnicas regionales que se han realizado, la anestesia del plexo braquial (APB) es la que representa mayores retos al anestesiólogo alrededor del mundo. Parece ser que el riesgo y la incidencia de complicaciones es mayor con abordaje supraclavicular. El pneumotórax casi ha desaparecido como complicación y se ha puesto mayor atención a la alteración respiratoria secundaria a la paresia unilateral del frénico. La incidencia de toxicidad por anestésicos locales es mayor con APB que con otros bloqueos y cuando se compara la incidencia de toxicidad sistémica comparando varios abordajes al plexo braquial, esta es cuatro veces mayor con el método supraclavicular, es por eso que se continua buscando nuevos métodos que sean más satisfactorios. La presente revisión describe los diferentes métodos y técnicas así como los beneficios y/o complicaciones derivadas de la APB

Pharmacokinetics of three doses of epidural ropivacaine during hysterectomy and comparison with bupivacaine.

PURPOSE: Ropivacaine is a new long-acting aminoamide local anaesthetic, structurally related to bupivacaine. The clinical efficacy of 125 mg, 187.5 mg and 250 mg ropivacaine have been reported and compared with 125 mg bupivacaine for epidural analgesia during hysterectomy. In the pharmacokinetic part of this study the objectives were to 1) determine the dose proportionality in the pharmacokinetics of epidural ropivacaine, and 2) compare the pharmacokinetics of 125 mg ropivacaine and 125 mg bupivacaine. METHODS: In a randomized, double-blind controlled study, patients received one of four treatment regimens with ropivacaine (125, 187.5 or 250 mg) or bupivacaine (125 mg) as a 25 ml epidural bolus administered over three minutes. Peripheral venous blood samples were collected over 24 hr for ropivacaine or bupivacaine quantification using gas chromatography with nitrogen sensitive detection. Pharmacokinetic variables were derived from plasma concentration-time curve data. RESULTS: Fifty two women entered the study. Demographic characteristics were similar among groups. Six patients were excluded due to inadequate sensory block or an insufficient number of plasma samples. The peak plasma concentration (Cmax) of ropivacaine and the total area under the plasma concentration-time curve (AUC) increased proportionally with the dose. Apparent plasma clearance (CL) and the terminal half-life (t1/2) were similar in the three ropivacaine groups. When compared with the 125 mg ropivacaine group, the bupivacaine group had a longer terminal half life (P < 0.05). CONCLUSIONS: Epidural ropivacaine displays dose-proportional pharmacokinetic behaviour for doses of 125 mg to 250 mg. Ropivacaine has a shorter terminal half-life than bupivacaine.

A double-blind comparison of ropivacaine 0.5%, 0.75%, 1.0% and bupivacaine 0.5%, injected epidurally, in patients undergoing abdominal hysterectomy.

PURPOSE: Ropivacaine is a new long-acting, injectable local anaesthetic currently undergoing clinical investigation world wide. It is structurally very similar to bupivacaine, but with less potential for central nervous system or cardiac toxicity. The purpose of this double-blind study was: to investigate the dose-response relationship of increasing doses of ropivacaine on the quality of anaesthesia and the duration of both motor and sensory blockade, and to compare these results with an established local anaesthetic, bupivacaine. METHODS: One hundred and twenty five patients were randomly assigned to one of four treatment groups and 116 completed the study. Epidural anaesthesia was established using 25 ml test solution, injected over three minutes following a satisfactory test dose. Sensory onset, spread and duration, using the pin prick method, and motor scores using a modified Bromage scoring system were compared. RESULTS: A dose/response relationship was observed with increasing doses of ropivacaine for all variables tested except analgesia and muscle relaxation (P < 0.01). There were differences in: (i) motor onset (Levels 1 and 2), when ropivacaine 1.0% was compared with ropivacaine 0.75% and 0.5% (P < 0.05); (ii) in sensory duration at all levels except T6 when ropivacaine was compared with ropivacaine 0.5% (P < 0.05); (iii) differences in sensory duration at T12 and S1 when ropivacaine 1.0% was compared with bupivacaine 0.5% (P < 0.05); (iv) differences in motor duration at all levels when ropivacaine 1.0% was compared with ropivacaine 0.5% (P < 0.05). No serious adverse events were reported in this study. CONCLUSION: Increasing doses of ropivacaine were associated with an increased clinical effect. The most consistent differences occurred when ropivacaine 1.0% was compared with 0.5% and the least consistent between ropivacaine 0.5%, 0.75% and bupivacaine 0.5%. The main difference between ropivacaine 1.0% and bupivacaine was in sensory duration. No serious adverse events were reported.

Neonatal resuscitation using the laryngeal mask airway.

BACKGROUND: For a newborn requiring positive-pressure ventilation (PPV), the American Heart Association recommends bag-and-mask ventilation, a challenging procedure for those inexperienced in neonatal resuscitation. The objective of this prospective study was to evaluate the laryngeal mask airway (LMA) as an alternative method of airway management in neonates requiring PPV at birth. METHODS: With the approval of the institutional ethics committee, consent was obtained from women in labor at a tertiary care-perinatal center. Inclusion criteria consisted of an expected birth weight of at least 2.5 kg, gestational age of at least 35 weeks, and resuscitation requiring PPV. Neonates meeting these criteria were resuscitated with PPV by means of the LMA. The ease of insertion, number of attempts required, time to establish effective ventilation, skin color, heart rate, respiratory effort, and Apgar scores were recorded. RESULTS: Attendance by the investigators at delivery was achieved in 93 cases, with 21 meeting the inclusion criteria. In all cases, the LMA was successfully inserted on the first attempt and provided a clinically patent airway. Twenty neonates were successfully resuscitated with the LMA to provide PPV, with no complications directly attributable to its use. One neonate required LMA removal and tracheal intubation to facilitate administration of epinephrine; data from this case was removed from the study. CONCLUSIONS: Providing PPV at birth via a size-1 LMA is effective and easily learned by personnel with expertise in neonatal resuscitation. The LMA should be further assessed as an alternative to bag-and-mask ventilation for this purpose.

Regional anaesthesia: complications and techniques.

In this review an effort has been made to highlight the most common and most important complications of regional anaesthesia and the most up-to-date treatment of these problems. For more complete information one should refer to the bibliography and major textbooks on this subject.

Safety of supplementing axillary brachial plexus blocks.

The incidence of failed local anesthetic axillary blockade varies but can be as high as 20-30%. The authors propose to evaluate the safety of supplementing an axillary block with mepivacaine 30 min after the initial injection. An axillary blockade was performed on 10 healthy patients scheduled for forearm or hand surgery using a new catheter technique. Mepivacaine 1% with epinephrine (7 mg/kg) was administered initially and followed 30 min later by half the original dose (3.5 mg/kg). Plasma levels of mepivacaine were estimated at frequent intervals for 5 h after the initial injection. There were no symptoms or signs of local anesthetic toxicity, and plasma levels of mepivacaine remained below those that usually caused symptoms. In conclusion, the authors conclude that mepivacaine 1% with epinephrine (10.5 mg/kg) can be safely administered in divided doses into the axillary sheath within a 31-min period.

Influence of age on vascular absorption of lidocaine from the epidural space.

The purposes of this study were to evaluate the effect of age on the vascular absorption of local anesthetics during epidural anesthesia and to corroborate the clinical observations of other investigators with respect to age. Using the arbitrary definition of significance (P less than 0.05), the maximum serum levels of lidocaine (Csmax) did not differ significantly with age, however, P values were equal to 0.06. Furthermore, the time to Csmax was significantly faster in elderly patients (P less than 0.00001). In conclusion, the mass of local anesthetic solution should be reduced in elderly patients undergoing epidural anesthesia because there is a greater segmental spread, and serum levels of local anesthetics are increased.