Complications following the use of the Combitube, tracheal tube and laryngeal mask airway

In a prospective, randomised trial, 75 patients scheduled for routine surgery were randomly allocated to one of three groups to evaluate trauma and postoperative complications after insertion of the Combitube, tracheal tube or laryngeal mask airway. Insertion of the Combitube was associated with a higher incidence of sore throat (48% vs. 16% vs. 12% [p < 0.01]) and dysphagia (68% vs. 12% vs. 8% [p < 0.01]) compared with tracheal intubation or insertion of the laryngeal mask airway, respectively. Hoarseness was significantly less common in both the Combitube and the laryngeal mask groups (both 12%) than in the tracheal tube group (44%; p < 0.01). Haematoma occurred in 36% of the Combitube group compared with 4% in both the laryngeal mask and the tracheal tube groups (p < 0.01). The higher incidence of complications should be considered when using the Combitube.     

A comparison of laryngeal mask airway with tracheal tube for intra-ocular ophthalmic surgery

The use of the laryngeal mask was compared with tracheal intubation in 30 patients who underwent intra-ocular ophthalmic surgery and who received intravenous anaesthesia with propofol. Changes in intra-ocular pressure, heart rate and mean arterial pressure after the insertion of the laryngeal mask airway or the tracheal tube were not significantly different. However, at the end of the procedure, a significantly higher percentage of patients with a tracheal tube coughed, reacted to head movement and suffered breath-holding. In addition, significantly more patients in this group complained of a sore throat (p less than 0.05). During intravenous propofol anaesthesia, the laryngeal mask airway does not offer any advantage over tracheal intubation in the control of intra-ocular pressure for intra-ocular ophthalmic surgery. However, there were fewer complications immediately following surgery in the laryngeal mask group.     

Tracheal intubation and sore throat: a mechanical explanation

Although tracheal intubation remains a valuable tool, it may result in pressure trauma and sore throat. The evidence for an association between these sequelae is not conclusive and sore throat may be caused at the time of intubation. This hypothesis was tested in a mechanical model and the results from tracheal intubation compared with those from insertion of a laryngeal mask airway, which is associated with a lower incidence of sore throat. Use of the model suggests that the tracheal tube and laryngeal mask airway impinge on the pharyngeal wall in different manners and involve different mechanisms for their conformation to the upper airway, but that in a static situation, the forces exerted on the pharyngeal wall are low with both devices. It also suggests that the incidence of sore throat should be lower for softer and smaller tracheal tubes and that the standard 'Magill' curve (radius of curvature 140 +/- 20 mm) is about optimum for the average airway.     

Tracheal intubation through the intubating laryngeal mask in patients with unstable necks

BACKGROUND: In patients with unstable necks, the neck should be stabilized during induction of anaesthesia, but this may make tracheal intubation difficult. Awake intubation may produce straining, which could be detrimental to the unstable neck. METHODS: We studied 20 patients with unstable necks to examine the efficacy of insertion of the intubating laryngeal mask under conscious sedation (to minimize the possibility of losing a patent airway and to facilitate fibrescope-aided intubation) followed by tracheal intubation through the laryngeal mask after induction of anaesthesia (to reduce stress response to intubation). After the patient had been sedated with midazolam (up to 5 mg) and fentanyl (up to 100 microg), the intubating laryngeal mask was inserted. General anaesthesia was then induced with sevoflurane and tracheal intubation attempted. RESULTS: In all patients, tracheal intubation through the laryngeal mask succeeded without airway obstruction. Neither insertion of the mask under conscious sedation nor tracheal intubation after induction of anaesthesia caused straining, and only two patients moved upper extremities at intubation. Insertion of the laryngeal mask did not significantly alter blood pressure or heart rate. Tracheal intubation significantly increased blood pressure and heart rate, but the increase was considered to be small. CONCLUSIONS: In the patient with an unstable neck with a low risk of pulmonary aspiration, insertion of the intubating laryngeal mask while the patient is sedated may minimize difficulty in obtaining a patent airway before tracheal intubation and may facilitate a fibrescope-aided tracheal intubation; subsequent induction of anaesthesia before tracheal intubation may minimize stress response to intubation.     

The pressor response and laryngeal mask insertion

The pressor response associated with laryngoscopy and tracheal intubation may be harmful to certain patients. The laryngeal mask airway avoids the need for laryngoscopy and allows positive pressure ventilation of the lungs in appropriate patients. This study compared the pressor response of tracheal intubation with that of mask insertion in two groups of 24 and 23 healthy patients respectively. All patients were anaesthetised with thiopentone, nitrous oxide, enflurane and paralysed with atracurium. We have shown a similar, but attenuated pattern of response associated with mask insertion in comparison with laryngoscopy and intubation; significant differences between the groups were evident in arterial diastolic blood pressure immediately after insertion and again 2 minutes later. Use of the laryngeal mask may therefore offer some limited advantages over tracheal intubation in the anaesthetic management of patients where the avoidance of the pressor response is of particular concern.     

The ProSeal laryngeal mask airway is an effective alternative to laryngoscope-guided tracheal intubation for gynaecological laparoscopy

We tested the hypothesis that the ProSeal laryngeal mask airway is superior to laryngoscope-guided tracheal intubation for gynaecological laparoscopy. One-hundred and eighty consecutive patients (ASA grade 1-2, aged 18-80 y) were divided into two equal-sized groups for airway management with the ProSeal laryngeal mask airway or tracheal tube. Induction was with fentanyl/propofol, maintenance with sevoflurane and muscle relaxation with atracurium. The following primary variables were tested: time to achieve an effective airway, ventilatory capability, peak airway pressure before and after pneumoperitoneum, duration of surgery and pneumoperitoneum and haemodynamic responses. Data about gastric size, airway trauma and sore throat were collected. The number of attempts for successful insertion were similar but effective airway time was shorter for the ProSeal laryngeal mask airway (20 +/- 2s vs 37 +/- 3 s, P < 0.001). All devices were successfully inserted within three attempts. There was no episode of failed ventilation or hypoxia. The haemodynamic stress responses to insertion and removal were greater for the tracheal tube than the ProSeal laryngeal mask airway. The duration of surgery, duration of pneumoperitoneum and intra-abdominal pressures were similar Gastric size was similar at the start and end of surgery. There were no differences in the frequency of complications or sore throat. We conclude that the ProSeal laryngeal mask airway is a similarly effective airway device to conventional laryngoscope-guided tracheal intubation for gynaecological laparoscopy, but is more rapidly inserted and associated with an attenuated haemodynamic response to insertion and removal.     

Cardiovascular responses to insertion of the laryngeal mask

We have compared, in 40 healthy patients, the cardiovascular responses induced by laryngoscopy and intubation with those produced by insertion of a laryngeal mask. Anaesthesia was induced with thiopentone and maintained with enflurane and nitrous oxide in oxygen; vecuronium was used for muscle relaxation. Arterial pressure was measured with a Finapres monitor. The mean maximum increase in systolic arterial pressure after laryngoscopy and tracheal intubation was 51.3% compared with 22.9% for laryngeal mask insertion (p less than 0.01). Increases in maximum heart rate were similar, (26.6% v 25.7%) although heart rate remained elevated for longer after tracheal intubation. We conclude that insertion of the laryngeal mask airway is accompanied by smaller cardiovascular responses than those after laryngoscopy and intubation and that its use may be indicated in those patients in whom a marked pressor response would be deleterious.     

Electroencephalographic arousal response during tracheal intubation and laryngeal mask airway insertion after induction of anaesthesia with propofol

Laryngoscopy and tracheal intubation, or insertion of a laryngeal mask airway may lead to an arousal response on the electroencephalogram. We studied whether more intense stimulation (laryngoscopy and tracheal intubation) causes a greater arousal response than less intense stimulation (laryngeal mask airway insertion). Thirty-four patients (ASA I-II) were anaesthetised with propofol 3 mg.kg-1, followed by vecuronium 0.15 mg.kg-1 and a propofol infusion of 10 mg.kg-1.h-1. Three minutes after induction of anaesthesia, either laryngoscopy and tracheal intubation (n = 18), or laryngeal mask airway insertion (n = 16) was performed. Laryngoscopy and tracheal intubation caused a significantly greater increase in blood pressure (but not heart rate) than laryngeal mask airway insertion (p < 0.05). Electroencephalogram responses were not different. More intense stimulation does not cause a greater arousal response during propofol anaesthesia.     

Tracheal intubation through the intubating laryngeal mask in a patient with a fixed flexed neck and deviated larynx

Insertion of the conventional laryngeal mask is more difficult or impossible when the patient's head and neck are in either the neutral or flexed position. The intubating laryngeal mask is best inserted when the patient's head is supported by a pillow, without placing the head and neck into the Magill position; therefore, insertion of this modified mask may be less difficult than the conventional mask in the patient with a flexed neck. We report a case of successful insertion of the intubating laryngeal mask and subsequent tracheal intubation through the mask using a fibre-optic bronchoscope, in a patient with a flexed neck in whom tracheal intubation using several methods had been difficult previously.     

Pharyngo-laryngeal discomfort after breast surgery: comparison between orotracheal intubation and laryngeal mask

Sore throat and dysphonia are a significant source of postoperative discomfort for patients scheduled for breast surgery who have been intubated for general anaesthesia. The aim of this study was to compare the incidence of postoperative pharyngo-laryngeal pain and dysphonia in the use of the laryngeal mask airway (LMA) or tracheal intubation in these patients. In a prospective, double-blind, randomised clinical trial we studied 53 women undergoing elective breast surgery to test the hypothesis that the use of the LMA could reduce the incidence of pharyngo-laryngeal morbidity compared with tracheal intubation. Postoperative sore throat and hoarseness were assessed at 6 and 24h by a standardised interview. The incidence of postoperative sore throat was significantly higher in the case of tracheal intubation at 6h (74% vs. 27%, p=0.0003) and at 24h (27% vs. 0%, p=0.004). The incidence of hoarseness was significantly higher in the tracheal intubation group than in the LMA group at 6h after surgery (40% vs. 15%, p=0.04), but not at 24h. Compared with tracheal intubation, the use of the LMA is associated with a lower incidence of postoperative sore throat and hoarseness and may contribute for improving patient comfort after breast surgery.     

The use of cricoid pressure with the intubating laryngeal mask

Unexpected difficulty with tracheal intubation contributes to anaesthetic morbidity and mortality. The intubating laryngeal mask is effective in facilitating blind intubation. We have evaluated the effect of cricoid pressure on the ability to insert an intubating laryngeal mask, and to pass a tracheal tube through it. Insertion and intubation through the mask were attempted in 50 patients, Mallampati grade 1-3, randomly allocated to cricoid and noncricoid pressure groups. Tracheal intubation was successful in 21 (84%) of the noncricoid group and 13 (52%) of the cricoid group (p = 0.03). Cricoid pressure may have to be released to allow correct placement and intubation through the intubating laryngeal mask.     

The haemodynamic response to the insertion of the laryngeal mask airway: a comparison with laryngoscopy and tracheal intubation

The haemodynamic response to the insertion of the laryngeal mask airway (LMA) was assessed and compared to that of laryngoscopy and tracheal intubation in a study of forty patients (ASA 1) randomly allocated into two groups and anaesthetised using a standard balanced anaesthetic technique. The results show that the changes in all cardiovascular parameters measured following LMA insertion were significantly less (P<0.05) when compared with those following laryngoscopy and tracheal intubation. We conclude that airway management with the LMA may be used to avoid the haemodynamic response to tracheal intubation where such a response is undersirable.     

The cardiovascular response to insertion of the intubating laryngeal mask airway

Sixty-one patients received a standardised anaesthetic and were randomly assigned to three groups: tracheal intubation via direct laryngoscopy, tracheal intubation via an intubating laryngeal mask airway with immediate removal of the device, and tracheal intubation via an intubating laryngeal mask airway with delayed removal. The cardiovascular response to intubation was of a similar magnitude in all groups, although delayed removal of the intubating laryngeal mask airway was associated with a second pressor response. Norepinephrine changed significantly over time following direct laryngoscopy and following immediate removal of the intubating laryngeal mask airway, but not after delayed removal. The findings of this study do not support using the intubating laryngeal mask instead of direct laryngoscopy purely to decrease the response to intubation.     

Postoperative sore throat: topical hydrocortisone

Forty patients undergoing tracheal intubation and controlled ventilation of the lungs for elective surgical procedures were studied. They were allocated randomly into one of two groups. The tracheal tubes used for group A patients were lubricated before insertion with water-soluble 1% hydrocortisone cream. Those for group B patients were lubricated with KY jelly. The incidence of postoperative sore throat was found to be significantly greater in group A. Topical 1% hydrocortisone cream is therefore ineffective in the prevention of postoperative sore throat.     

Ist die Kehlkopfmaske ein minimal invasives Instrument zur Sicherung der Atemwege? Ergänzende Bemerkungen zum Beitrag „Schäden und Gefahren durch Einsatz der Kehlkopfmaske” von V. Hempel Anaesthesist (1999) 48:399–402

Minor laryngopharyngeal complaints following anaesthesia considerably determine postoperative patient comfort. They cannot be eliminated but reduced by experience and careful preparation and insertion technique. The incidence of minor laryngopharyngeal symptoms following the use of the laryngeal mask airway is similar to that following endotracheal intubation. However, there seems to be a distinct pattern of complaints: discomfort with swallowing is more frequent after LMA, whereas dysphonia is more often observed following endotracheal intubation. The significance of LMA cuff pressures in the pathogenesis of postoperative throat complaints remains unclear. There is sound evidence that cuff pressure is not a representative measure for the effective pressure load upon the pharyngeal mucosa. Measurement of cuff pressure is not obligatory, instead reduction of cuff volume to a "just seal" situation seems to be a reasonable approach. The laryngeal mask airway has definitely changed anaesthesiology airway management. Whether this is due to its supposedly less invasiveness compared to endotracheal intubation has not been proven by scientific investigations.     

喉罩与气管插管麻醉下“三孔式”非肌无力胸腺瘤切除术的对比研究

目的探讨喉罩全身麻醉(全麻)代替气管插管全麻用于经剑突、肋缘下"三孔式"前纵隔病变切除术治疗不合并肌无力的胸腺瘤患者的安全性和可行性。方法纳入我科2018年1月至2019年6月连续收治的行"三孔式"前纵隔病变切除术治疗不合并肌无力的胸腺瘤患者109例。根据麻醉方式不同,将患者分为气管插管全麻组和喉罩全麻组。气管插管全麻组患者共70例,其中男42例、女28例,平均年龄(45.83±15.89)岁;喉罩全麻组患者共39例,其中男26例、女13例,平均年龄(43.31±15.64)岁。比较两组患者的临床资料。结果两组患者基线特征差异无统计学意义(P>0.05)。所有患者均未出现大出血、中转为开胸、术后并发肌无力、死亡等情况。喉罩全麻组患者术中无中转为气管插管全麻者。两组患者在手术时间、术中出血量、术中最高CO2分压、最低氧分压值、麻醉效果评分等方面差异无统计学意义(P>0.05)。两组患者在术后误吸、胃肠道不适、住院时间、疼痛评分、患者满意度等方面差异无统计学意义(P>0.05)。但喉罩全麻组患者手术前麻醉所用时间、麻醉清醒所用时间均明显短于气管插管全麻组患者(P<0.05),而且喉罩全麻组患者术中一过性心律失常、术后咽喉部不适及声音嘶哑发生率均明显低于气管插管组患者(P<0.05)。结论在喉罩全麻下行经剑突、肋缘"三孔式"前纵隔病变切除术治疗不合并肌无力胸腺瘤患者是安全、可行的,可尝试常规推荐使用。     

A comparison of the intubating laryngeal mask tracheal tube with a standard tracheal tube for fibreoptic intubation

We conducted a prospective randomised study to compare the intubating laryngeal mask tracheal tube with a standard tube, for ease of tracheal intubation over a fibrescope. Thirty-six patients were investigated, using a sequential analysis technique. Ease of intubation was improved when the intubating laryngeal mask tracheal tube was used compared with the standard tube (p = 0.0009). Median (interquartile range [range]) intubation times (time from the tube's tip being level with the patient's teeth to successful placement) were 1.5 (1-2.3 [1-3]) s when the intubating laryngeal mask tracheal tube was used and 5 (3-7.3 [3-13]) s when the standard tube was used (p < 0.0001).     

Emergence characteristics and postoperative laryngopharyngeal morbidity with the laryngeal mask airway: a comparison of high versus low initial cuff volume

In this study we tested the hypothesis that the initial cuff volume of the laryngeal mask airway influences emergence characteristics and postoperative laryngopharyngeal morbidity. One hundred and sixty adult patients undergoing minor surgery were randomly assigned for airway management with the laryngeal mask airway with either a fully inflated cuff (LMA-High) or a semi-inflated cuff (LMA-Low). Anaesthesia was with propofol, nitrous oxide, oxygen and isoflurane. Following insertion, the cuff was inflated with either 15 or 30 ml for the size 4 (females) and 20 or 40 ml for the size 5 (males). At the end of surgery, a blinded observer documented the presence or absence of adverse airway events (hypoxia, hypercapnea, coughing, retching, regurgitation/vomiting, airway obstruction, hypoventilation, hiccupping, biting, body movement or shivering) during every 1 min epoch and cardiorespiratory variables (heart rate, mean blood pressure, arterial oxygen saturation, end-tidal carbon dioxide and respiratory rate) every 5 min until the patient was awake and the laryngeal mask airway removed. Patients were interviewed about pharyngolaryngeal morbidity (sore throat, dysphonia and dysphagia) immediately before leaving the postanaesthesia care unit and 18-24 h following surgery. Analysis by epoch showed more partial airway obstruction in the LMA-High group, but analysis by patient numbers revealed no difference. Heart rate was slightly higher in the LMA-High group upon arrival in the postanaesthesia care unit, but otherwise there were no differences in cardiorespiratory responses. Sore throat and dysphagia were more common in the LMA-High group. We conclude that, in general, emergence characteristics with the laryngeal mask airway are not influenced by the volume of air used to inflate the cuff, but that postoperative sore throat and dysphagia are more likely at high initial cuff volumes.     

Intra-ocular pressure changes using the laryngeal mask airway and tracheal tube

Intra-ocular pressure was measured before and throughout airway establishment with either the laryngeal mask airway or tracheal tube. Similar measurements were made on removal of either airway and the amount of coughing noted in the first minute after removal. There was a significantly smaller increase in intra-ocular pressure (p less than 0.001) using the laryngeal mask airway, both on placement and removal, than with the tracheal tube. Postoperative coughing was significantly reduced using the laryngeal mask airway (p less than 0.001). There was a significantly greater rise in heart rate using the tracheal tube (p less than 0.01) probably related to an increased cardiovascular response. The laryngeal mask airway is recommended as an alternative to tracheal intubation in routine and emergency intra-ocular surgery.     

The laryngeal mask airway

Two cases of emergency prehospital airway control using the laryngeal mask are described. The patients were trapped following road traffic accidents and limited access prevented tracheal intubation. The laryngeal mask airway may be a useful alternative to tracheal intubation in some cases of prehospital trauma care.