A series of thyroplasty cases under general anaesthesia

Thyroplasty is an operation on the upper airway to improve voicequality in patients with unilateral vocal cord paralysis. Itrequires access to an uninstrumented larynx and a functionalassessment of vocal cord medialization. It is a difficult anaestheticprocedure that requires sharing the airway with the surgeon.We describe an anaesthetic technique to give good operatingconditions and a safe airway, using total intravenous anaesthesia,a laryngeal mask airway and intraoperative fibreoptic endoscopicassessment of the larynx, and present a series of 13 patients.Other anaesthetic techniques for thyroplasty are described anddiscussed. Br J Anaesth 2000; 85: 547-9 ^* Corresponding author: Flat 4, Tall Trees, 8 Mersey Road, Didsbury,Manchester M20 2PE, UK     

Shorter discharge time after regional or intravenous anaesthesia in combination with laryngeal mask airway compared with balanced anaesthesia with endotracheal intubation

BACKGROUND AND OBJECTIVE: The efficiency of operating room times can be significantly improved using rapid changes between operative procedures. We performed a retrospective analysis using electronic anaesthesia charts that compared anaesthesia-related times between the three most frequently performed types of anaesthesia (for orthopaedic surgery) to evaluate the potential for a quicker turn-around between cases. METHODS: A total of 5614 anaesthetic procedures in trauma-related orthopaedic surgery were performed from 1997 to 1999. All were documented with an automatic record-keeping system. Data were compared for intravenous anaesthesia with the laryngeal mask airway, balanced anaesthesia with tracheal intubation and regional anaesthesia. The primary outcome measure was the time needed for emergence from anaesthesia after the end of surgery. Statistical evaluation was performed with matched triples for all three types of anaesthesia (155 triples for ambulatory surgery, 249 triples for in-patient care). RESULTS: For ambulatory surgery, the induction time was significantly shorter for general anaesthesia (23.7 min for intravenous anaesthesia, 22.7 min for balanced anaesthesia techniques) compared with regional anaesthesia (27.2 min). The time from the end of the surgical procedure to transfer of the patient out of the operating room was shortest for regional anaesthesia (6.3 min) compared with intravenous anaesthesia (9.0 min) and balanced anaesthesia (12.5 min) techniques. Results were comparable for in-patients: regional anaesthesia required significantly longer for its induction, but less time for patient discharge from the operating room. CONCLUSIONS: The use of a regional anaesthesia technique or one involving intravenous anaesthesia in combination with the laryngeal mask airway may lead to a reduction in discharge time compared with a balanced anaesthesia technique with endotracheal intubation. Thus, improved use of resources may be achieved.     

Laryngeal mask and anaesthetic waste gas exposure

In recent years there has been a growing awareness of the possible hazards caused by anaesthetic gases in operating theatres. The laryngeal mask airway provides an alternative both to tracheal intubation and the face mask although the implications for operating theatre contamination have not been quantified. This paper describes the incidence and magnitude of exposure of theatre personnel to waste anaesthetic gases during laryngeal mask airway anaesthesia. The leakage of anaesthetic gases to the anaesthetist's breathing zone was monitored using a Bruel & Kjaer Multi Gas Monitor, Type 1302 during 50 general anaesthetics employing either spontaneous (n = 24) or controlled (n = 26) ventilation. All patients were anaesthetised with propofol, alfentanil and nitrous oxide. There was no statistically significant association between the amount of anaesthetic gas leakage and ventilation method. The laryngeal mask airway meets occupational safety requirements on nitrous oxide concentrations in the operating theatre environment.     

Safety and efficacy of the laryngeal mask airway A prospective survey of 1400 children

A survey of laryngeal mask airway usage in 1400 infants and children by ten trainee anaesthetists was undertaken to provide information about insertion and complication rates using the standard insertion technique and a limited range of standardised anaesthetic techniques. Placement was successful in 90% (1258/1400) at the first attempt, 8% (112/1400) at the second attempt and 2% (29/1400) required an alternative technique of insertion. One patient vomited during insertion and the procedure was abandoned, hut aspiration did not occur. The overall problem rate was 11.5% and there were significantly more problems during induction of anaesthesia (p < 0.02). Oxygen saturation decreased below 90% briefly on 23 occasions (1.7%). The incidence of problems was unrelated to the mode of ventilation, or whether isoflurane or total intravenous anaesthesia with propofol was used for maintenance. Most problems came with use of the size 1 laryngeal mask (p < 0.001). The subspecialty with the highest problem rate was ear, nose and throat surgery (p < 0.001). There was a significant decrease in problems with increasing experience (p < 0.001). There was no major morbidity associated with use of the device. We conclude that the laryngeal mask provides a safe and effective form of airway management for infants and children in the hands of supervised anaesthesia trainees both for spontaneous and controlled ventilation using either isoflurane or total intravenous anaesthesia.     

Anaesthetic management of a patient with myotonic dystrophy

A 13-year-old boy with myotonic dystrophy underwent insertion of a percutaneous gastrostomy feeding tube under general anaesthesia. We used a laryngeal mask airway and a spontaneously breathing technique with propofol total intravenous anaesthesia. Postoperative vomiting and aspiration, 12 h after the procedure, subsequently required intubation and ventilation. We discuss the anaesthetic management of this case and review the features of the disease to be considered when contemplating anaesthesia in such patients.     

Laryngeal nerve monitoring during thyroid surgery in pregnancy

A 32-week parturient required partial thyroidectomy for suspicious carcinoma. The surgeon requested laryngeal nerve monitoring to decrease the chances of laryngeal nerve injury during surgery. After rapid-sequence induction of general anesthesia and intubation, a size 3 laryngeal mask airway was inserted posterior to the endotracheal tube and the cuff inflated with 15 mL of air. A fiberoptic bronchoscope inserted through the laryngeal mask airway provided an unhindered view of vocal cords for laryngeal nerve identification and testing during surgery. This combined technique also offered the advantages of a secured airway, as well as positive pressure ventilation in the parturient during thyroid surgery.     

Remifentanil vs. alfentanil infusion in non-paralysed patients: a randomized, double-blind study

BACKGROUND AND OBJECTIVE: Remifentanil has a short duration of action and constant elimination, which allow administration of high doses, without prolonging recovery. Remifentanil has been compared to alfentanil, as part of a total intravenous anaesthetic technique, where remifentanil provided better anaesthetic conditions than alfentanil, without adverse effect on recovery. However, these results were obtained during anaesthesia involving neuromuscular blockade, which may mask both signs of insufficient anaesthesia and side-effects such as muscle rigidity. The aim of this study was to compare remifentanil with alfentanil for anaesthesia without neuromuscular blockade. METHODS: We performed a prospective, randomized, double-blind, four-centre study to compare remifentanil infusion 15 microg kg(-1) h(-1) and alfentanil infusion 60 microg kg(-1) h(-1), using a total intravenous technique for non-paralysed patients, and the laryngeal mask airway for airway management. We enrolled 192 patients, 18-65 yr of age with ASA I-II, undergoing minor surgery. The primary endpoint was the number of patients having pre-defined responses to surgical stimulation. A number of secondary criteria was evaluated to assess undesirable properties of the procedures. RESULTS: In the alfentanil group, 85% of patients responded to surgical stimulation, vs. 35% in the remifentanil group (P < 0.0001). No difference was found in recovery data, or in any other parameter than those related to insufficient anaesthesia. CONCLUSIONS: The remifentanil-based technique provided significantly better anaesthetic conditions than the alfentanil-based technique in the setting of this study, without causing any significant adverse effects.     

The laryngeal mask and VBM laryngeal tube compared during spontaneous ventilation. A pilot study.

BACKGROUND AND OBJECTIVE: The laryngeal tube is a variant of the oesophageal obturator airway. The manufacturer claims that it is an alternative to ventilation with a facemask, laryngeal mask or endotracheal tube. To date, published studies have only involved controlled ventilation. We wished to find out if its use in spontaneous ventilation was equivalent to using the laryngeal mask airway. METHODS: We have compared the laryngeal tube with the laryngeal mask in a randomized prospective study involving patients breathing spontaneously under general anaesthesia. Criteria and a scoring system were used for the comparison. A sequential analysis chart with P=0.01 was chosen for each of two anaesthetists. RESULTS: Only seven and 10 pairs of patients were required to indicate that the laryngeal tube was poorer at airway maintenance than the laryngeal mask. Of the 17 patients who had received the laryngeal tube, successful airway maintenance was only possible in seven. In the remaining 10 patients, the laryngeal tube was abandoned and the rescue airway was the laryngeal mask in all cases. All 17 patients randomized to the laryngeal mask were successfully managed. CONCLUSIONS: We conclude that the laryngeal tube is not a satisfactory device for management of the airway during spontaneous ventilation.     

Anaesthetic management for insertion of the Montgomery T-tube in a patient with subglottic stenosis

We report a patient with subglottic stenosis who required insertion of the Montgomery T-tube. During the operation, we could keep stable anaesthesia and adequate ventilation under general anaesthesia using continuous intravenous infusion of propofol with laryngeal mask airway (LMA).     

Minimal-flow anaesthesia with controlled ventilation: comparison between laryngeal mask airway and endotracheal tube.

BACKGROUND AND OBJECTIVE: Minimal- and low-flow anaesthesia (fresh gas flow below 1 L min(-1)) provide many advantages, including reduced cost, conservation of body heat and airway humidity. An airtight seal is essential between the airway device and the airway of the patient. Therefore, we investigated whether the airtight seal created by a laryngeal mask airway allows controlled ventilation of the lungs when the fresh gas flow is reduced to 0.5 L min(-1) and compared this with an endotracheal tube. METHODS: In a prospective clinical study, 207 patients were managed using a laryngeal mask or an endotracheal tube. After intravenous induction of anaesthesia and 15 min of high fresh gas flow, the flow was reduced to 0.5 L min(-1). The breathing system was monitored for airway leaks, and the patients were assessed for complications after airway removal and postoperative discomfort. RESULTS: Both the laryngeal mask and endotracheal tube allowed fresh gas flow reduction to 0.5 L min(-1) in 84.7% and 98.3% of cases respectively (small leaks: 12% laryngeal mask, 1.7% endotracheal tube). Three patients with the laryngeal mask (3.3%) had airway leaks that were too large to permit any reduction in the fresh gas flow. CONCLUSIONS: The use of the laryngeal mask airway was more likely to be associated with a gas leak than use of an endotracheal tube; however, if modern anaesthesia machines and monitors are used, in 96.7% of the patients managed with a laryngeal mask a reduction in the fresh gas flow to 0.5 L min(-1) was possible. The incidence of coughing and postoperative complaints (sore throat, swallowing problems) was higher after use of an endotracheal tube.     

The site of airway irritation during induction of anaesthesia

The aim of this investigation was to study the role of the nasal airway in mediating upper airway reflexes during induction of anaesthesia when the commonly used irritant inhalational anaesthetic agent enflurane is used. In a prospective randomised study, 40 ASA 1 & 2 day-case patients undergoing body surface surgery were recruited. Following intravenous induction using propofol, 20 patients received enflurane administered via a laryngeal mask airway (LMA), the anaesthetic vapour therefore bypassing the nasal airway. In the other group, 20 patients received enflurane anaesthesia administered using a face mask, the nasal airway therefore being exposed to inhalation anaesthetic. We were unable to demonstrate any significant (p < 0.05) differences between the two groups in relation to upper airway complications (cough, breath holding, laryngeal spasm, bronchospasm and excitement). Previous work has identified the nose as a possible important reflexogenic site for upper airway reflexes in humans during anaesthesia. We have been unable to demonstrate any difference in upper airway complications when the nasal airway was included or excluded from exposure to irritant anaesthetic vapours, when administered in a clinical setting.     

Tracheal tubes for maxillofacial and dental surgery

Maxillofacial and dental surgery have developed with anaesthesia. This is because of the mutual understanding that is necessary for safe and successful surgery on the ‘shared airway’. The choice of airway management technique is influenced by patient factors, surgical requirements and anaesthetic preferences. Good communication between surgeon and anaesthetist is imperative for the safety of the patient and the smooth running of the surgery. The anaesthetic considerations include: dealing with the difficult airway; the risk of obstruction, transection, disconnection or removal of the airway intraoperatively; the risk of soiling of the airway due to bleeding and surgical debris such as tooth or bone fragments; and the potential for airway compromise postoperatively. A cuffed tracheal tube with a throat pack provides the highest level of airway protection in shared airway surgery, but may not always be the most suitable technique. A north polar nasal tube provides a secure airway and excellent surgical access for surgery on the jaws, teeth, oral cavity and neck; it also allows intermaxillary fixation (wiring of the jaws) and assessment of dental occlusion. South facing preformed oral (RAE) tubes are suitable for procedures involving the nose, upper mid face and forehead. Submental intubation provides an alternative to oral and nasal tracheal intubation and is useful in selected procedures. The laryngeal mask airway (LMA) has an important role intraoperatively and provides smooth emergence from anaesthesia. Transtracheal catheter and jet ventilation is seldom used in maxillofacial anaesthesia, but is an important rescue technique. An elective tracheostomy should be considered if significant postoperative airway compromise is anticipated and may occasionally be necessary under local anaesthesia before induction. It requires surgical expertise and carries a high incidence of morbidity. This article discusses how to select appropriate tracheal tubes for maxillofacial and dental surgery.     

Use of the laryngeal mask airway in thyroid and parathyroid surgery as an aid to the identification and preservation of the recurrent laryngeal nerves.

A prospective study was carried out in patients undergoing thyroid and parathyroid surgery using a laryngeal mask airway (LMA) and electrical nerve stimulation to identify the recurrent laryngeal nerves. A total of 150 consecutive patients undergoing thyroid and parathyroid surgery by a single surgeon were assessed for suitability of anaesthesia via the LMA. Peroperatively, a fibre-optic laryngoscope was passed through the LMA to enable the anaesthetist to visualise the vocal cords while adduction of the cords was elicited by applying a nerve stimulator in the operative field. In all, 144 patients were selected for anaesthesia via the LMA. Fibre-optic laryngoscopy and nerve stimulation were performed in 64 patients (42.7%). The trachea was deviated in 51 (34.0%) and narrowed in 33 (22.0%). The recurrent laryngeal nerves were identified in all patients. There were no cases of vocal cord dysfunction resulting from surgery. The LMA can be safely used for thyroid and parathyroid surgery even in the presence of a deviated or narrowed trachea. It can assist in identification and preservation of the recurrent laryngeal nerve and is, therefore, of benefit to both patient and surgeon.     

鼻咽通气道复合面罩通气与喉罩通气在短小日间手术中的应用比较

目的 比较鼻咽通气道复合面罩通气与喉罩通气下静吸复合全麻在短小日间手术中的应用效果.方法 选择估计1h内的日间手术患者90例,随机均分为鼻咽通气道复合面罩组(面罩组)和喉罩组.记录诱导前(T0)、插入鼻咽通气道或喉罩前1 min(T1)、插入鼻咽通气道或喉罩即刻(T2)、切皮时(T3)、拔出鼻咽通气道或喉罩前1 min(T4)、拔出鼻咽通气道或喉罩即刻(T5) MAP、HR、PET CO2、SpO2、RR和VT;记录插入喉罩或鼻咽通气道的时间和一次成功率;记录清醒时间和离院时间,从麻醉开始至拔出鼻咽通气道或喉罩时出现体动、呼吸道梗阻、反流误吸以及术后出现咽痛、吞咽困难和声音嘶哑的患者例数.结果 两组患者诱导后均能较好的保留自主呼吸,维持稳定的RR、VT和PETCO2,T2、T5时喉罩组MAP明显高于、HR明显快于面罩组(P＜0.05),插入鼻咽通气道时间明显短于插入喉罩的时间(P＜0.05),一次性插入鼻咽通气道的成功率高于一次性插入喉罩的成功率(P＜0.05),术中和术后不良反应喉罩组高于面罩组(P＜0.05).结论 鼻咽通气道复合面罩通气下静吸复合全麻用于短小日间手术能够维持循环和呼吸的稳定,苏醒迅速,在日间手术中是一种安全有效的麻醉方法.     

General anaesthesia for dentistry

Dental anaesthesia developed down a different pathway from the rest of anaesthesia. Techniques such as nasal mask anaesthesia in the sitting position were specific to dental surgery, which took place largely outside hospital in dental clinics. Now dental anaesthesia is confined to locations within the aegis of a hospital and anaesthetic techniques are similar to those in other surgical specialties. Dental surgery consists of extractions and conservation. Short procedures for the extraction of teeth may still be carried out using a nasal mask, but more difficult extractions and conservation procedures are best done with a laryngeal mask or endotracheal tube. Close liaison with the dental surgeon is imperative in the planning of the anaesthetic technique. The anaesthetist must support the jaw and head in order to provide counter-pressure to help the dentist and to prevent excessive movement of the neck. Patients needing general anaesthesia include children, those with allergy to local anaesthetics, and adults with special needs who may need premedication to enable induction to take place. During the recovery phase, the airway has to be watched carefully as the potential for obstruction is great and deaths have occurred. Paracetamol is a useful analgesic for extraction of deciduous teeth, and non-steroidal analgesics are used for pain control after extraction of permanent teeth, which is more painful. In addition, local anaesthetic injections are helpful in older children.     

Inhalational induction of anaesthesia with 8% sevoflurane in children: conditions for endotracheal intubation and side-effects

BACKGROUND AND OBJECTIVE: This study was designed to assess the conditions for endotracheal intubation or insertion of a laryngeal mask airway following an inhalational induction using 8% sevoflurane and nitrous oxide without the use of muscle relaxants or opioids. METHODS: There were two groups: 30 children had endotracheal intubation and 30 children had a laryngeal mask airway inserted. Induction of anaesthesia was accomplished using an inspiratory concentration of sevoflurane 8% in a nitrous oxide and oxygen mixture. After an end-expiratory concentration of sevoflurane of at least 4% had been reached, when the pupils were miotic and centred, the trachea was intubated or a laryngeal mask inserted. The time to loss of consciousness and successful airway management was recorded. Jaw relaxation, movements, visibility, and position of the vocal cords and vital parameters were monitored. RESULTS: Jaw relaxation was complete in all children. The vocal cords were completely visible in all patients of the tracheal intubation group, whereas vocal cord relaxation was incomplete in five children. Nevertheless, all children had an atraumatic intubation or insertion of the laryngeal mask without the use of a muscle relaxant. Vital signs were stable in both groups. There were no cases of restlessness and/or postoperative shivering. Four patients in the endotracheal group (13.3%) were nauseous and three (10%) vomited, while two children (6.6%) in the laryngeal mask group experienced nausea and vomiting. CONCLUSIONS: Induction with sevoflurane in nitrous oxide and oxygen leads to fast loss of consciousness and provides ideal conditions for managing the airway without supplemental opioids or muscle relaxants. Furthermore, sevoflurane using this technique was very well tolerated, indicated by high haemodynamic stability and a reduced rate of postoperative restlessness, shivering, nausea and vomiting.     

Comparison of the GlideScope video laryngoscope vs. the intubating laryngeal mask for females with normal airways

BACKGROUND AND OBJECTIVE: In this randomized clinical study, we compared the intubation success rates of the intubating laryngeal mask airway with the GlideScope in patients with normal airways. The primary hypothesis was that the intubating laryngeal mask airway was equally effective as the GlideScope in terms of successful intubation times. METHODS: Sixty ASA I and II adult patients undergoing elective gynaecological surgery were randomly allocated into either the intubating laryngeal mask airway group or the GlideScope group. After a standard anaesthetic intravenous induction, orotracheal intubation was performed. Time taken for successful tracheal intubation, ease of device insertion, difficulty of tracheal intubation, manoeuvres needed to aid tracheal intubation, number of intubation attempts, haemodynamic changes every 2.5 min interval for 5 min and complications during tracheal intubation were recorded. RESULTS: Time to successful intubation was longer (mean 68.4 s +/- 23.5 vs. 35.7 s +/- 10.7; P < 0.05), mean difficulty score was higher (mean 16.7 +/- 16.3 vs. 7.3 +/- 13.1; P < 0.05) and more intubation attempts were required in the intubating laryngeal mask airway group. CONCLUSION: The GlideScope improved intubation time and difficulty score for tracheal intubation when compared with the intubating laryngeal mask airway in our patients. Blind intubation through the intubating laryngeal mask airway offers no advantages over the GlideScope in patients with normal airways. Despite its limitations, the intubating laryngeal mask airway is a valuable adjunct, especially in cases of difficult airway management when it can provide ventilation in between intubation attempts.     

Jet ventilation for the excision of vocal cord polyps in a pregnant patient

The anaesthetic management of patients presenting with laryngeal tumours and airway obstruction is difficult. We present the case of a pregnant woman at 30 weeks gestation who underwent surgical removal of two vocal cord polyps under general anaesthesia using jet ventilation     

The reinforced laryngeal mask in dental day surgery

Sixty adult patients undergoing removal of third molars under general anaesthetic in the Cambridge day surgery unit were randomly allocated to receive either a conventional anaesthetic employing nasotracheal intubation (NETT), pharyngeal gauze pack and inhalation agents or the reinforced laryngeal mask airway (RLMA) and total intravenous anaesthesia. Thirty patients were studied in each group. Immediate recovery times were significantly longer in the NETT group (P = 0.01). Surgical access was adequate in both groups. Postoperative muscle pains were significantly less in the reinforced laryngeal mask airway (RLMA) group (P= 0.0001). The RLMA provides a reliable method of airway management during removal of impacted third molars, with a reduction in postoperative morbidity when compared with conventional nasotracheal intubation involving the use of suxamethonium.     

The shared airway

Anaesthesia for the shared airway requires close co-operation and communication between anaesthetist and surgeon for a safe airway and adequate surgical access. The anaesthetist needs to maintain a patent airway, ensure adequate oxygenation, carbon dioxide removal and prevent soiling of the bronchial tree while the surgeon requires adequate access, and for certain endoscopic procedures a clear view of a motionless field. Surgical procedures vary from routine endoscopic examination to complex microsurgery and laser surgery of the larynx, and no ideal universally accepted anaesthetic technique exists to cover this wide range of shared airway cases. Laser airway surgery requires special safety considerations for both operating theatre staff and patients due to the danger of deflected laser radiation and the risk of airway fire. Anaesthetic techniques can be divided into three main groups. First, intubation techniques requiring the presence of either a small or large tracheal tube; second, non-intubation techniques including use of the laryngeal mask airway, apnoeic techniques and insufflation techniques and third, jet ventilation techniques via a supraglottic, subglottic or transtracheal route.