Pharyngolaryngeal morbidity with the laryngeal mask airway in spontaneously breathing patients: does size matter?

BACKGROUND: Currently, the manufacturer of the laryngeal mask airway (LMA; Laryngeal Mask Company, Ltd., Northfield End, Henley on Thames, Oxon, United Kingdom) recommends using as large a mask size as possible. The aim of this study was to compare the incidence of pharyngolaryngeal morbidity after the use of a large (size 5 in males and size 4 in females) or small (size 4 in males and size 3 in females) LMA in spontaneously breathing patients. METHODS: A total of 258 male and female patients were randomly assigned to insertion of a large or small LMA while breathing spontaneously during general anesthesia. After insertion of the LMA, a "just-seal" cuff pressure was obtained, and intracuff pressure was measured at 10-min intervals until just before removal of the LMA. The 2- and 24-h incidence of postoperative sore throat, pain, hoarseness, dysphagia, and nausea and vomiting was assessed. Complications after LMA removal, including body movement, coughing, retching, regurgitation, vomiting, biting on the LMA, bronchospasm, laryngospasm, or the presence of blood on the LMA, were recorded. RESULTS: The use of a large LMA was associated with a higher incidence of sore throat in both sexes (20% vs. 7% in men, 21% vs. 5% in women; P < 0.05) and a higher incidence of hoarseness in male patients at 2 h postoperatively (21% vs. 9%, P < 0.05). There was a higher incidence of sore throat in male patients at 24 h postoperatively with the use of a large LMA (26% vs. 12%, P < 0.05). There was no difference in the incidence of complications of LMA removal orother pharyngolaryngeal morbidity, such as difficulty swallowing, drinking, and eating, or nausea and vomiting, between male or female groups at any time period with the use of a large LMA. CONCLUSIONS: Selection of a small laryngeal mask airway (size 4) in spontaneously breathing male patients may be more appropriate to limit the occurrence of sore throat on the first postoperative day. All patients had a fourfold increased risk of developing sore throat when a large LMA was used.     

Pharyngolaryngeal Morbidity with the Laryngeal Mask Airway in Spontaneously Breathing Patients: Does Size Matter?

Background: Currently, the manufacturer of the laryngeal mask airway (LMA(TM); Laryngeal Mask Company, Ltd., Northfield End, Henley on Thames, Oxon, United Kingdom) recommends using as large a mask size as possible. The aim of this study was to compare the incidence of pharyngolaryngeal morbidity after the use of a large (size 5 in males and size 4 in females) or small (size 4 in males and size 3 in females) LMA in spontaneously breathing patients.

Methods: A total of 258 male and female patients were randomly assigned to insertion of a large or small LMA while breathing spontaneously during general anesthesia. After insertion of the LMA, a "just-seal" cuff pressure was obtained, and intracuff pressure was measured at 10-min intervals until just before removal of the LMA. The 2- and 24-h incidence of postoperative sore throat, pain, hoarseness, dysphagia, and nausea and vomiting was assessed. Complications after LMA removal, including body movement, coughing, retching, regurgitation, vomiting, biting on the LMA, bronchospasm, laryngospasm, or the presence of blood on the LMA, were recorded.

Results: The use of a large LMA was associated with a higher incidence of sore throat in both sexes (20%vs. 7% in men, 21%vs. 5% in women;P < 0.05) and a higher incidence of hoarseness in male patients at 2 h postoperatively (21%vs. 9%, P < 0.05). There was a higher incidence of sore throat in male patients at 24 h postoperatively with the use of a large LMA (26%vs. 12%, P < 0.05). There was no difference in the incidence of complications of LMA removal or other pharyngolaryngeal morbidity, such as difficulty swallowing, drinking, and eating, or nausea and vomiting, between male or female groups at any time period with the use of a large LMA.     

Pharyngolaryngeal, neck, and jaw discomfort after anesthesia with the face mask and laryngeal mask airway at high and low cuff volumes in males and females

BACKGROUND: There is controversy over (1) the relative incidence of sore throat between the face mask (FM) and laryngeal mask airway (LMA), (2) the efficacy of LMA intracuff pressure reduction as a mechanism for minimizing sore throat, and (3) the relative incidence of sore throat with the LMA between males and females. In a randomized double-blind study, the authors compared laryngopharyngeal, neck, and jaw discomfort with the FM and LMA at high and low cuff volumes in males and females. METHODS: Three hundred adult patients were randomly assigned to three equal-sized groups for airway management: (1) the FM, (2) the LMA with a fully inflated cuff (LMA-High), or (3) the LMA with a semi-inflated cuff (LMA-Low). Anesthesia was administered with propofol, nitrous oxide, oxygen, and isoflurane. In the FM group, a Guedel-type oropharyngeal airway and jaw thrust were used only if necessary. In the LMA groups, cuff inflation was achieved with either 15 or 30 ml for the size 4 (females) and 20 or 40 ml for the size 5 (males). The LMA was removed when the patient was awake. Patients were questioned 18-24 h postoperatively about surgical pain, sore throat, sore neck, sore jaw, dysphonia, and dysphagia, and about whether they were satisfied with their anesthetic. RESULTS: The incidence of sore throat was lower in the FM (8%) than the LMA-High (42%) and LMA-Low (20%) groups (both: P < or = 0.02). The incidence of sore neck was higher for the FM (14%) than the LMA-High group (6%; P = 0.05) but similar to the LMA-Low group (8%). The incidence of sore jaw was higher in the FM (11%) than the LMA-High (3%) and LMA-Low (3%) groups (both: P = 0. 02). There were no differences among groups for surgical pain or dysphonia. The incidence of dysphagia was lower in the FM (1%) than the LMA-High group (11%; P = 0.003), but similar to the LMA-Low group (1%). The incidence of sore throat and dysphagia was lower in the LMA-Low group than the LMA-High group for both males and females (all: P < or = 0.04). There were no differences in discomfort levels between males and females in any group. Two patients from the FM group and one from the LMA-High group were not satisfied with their anesthetic. These complaints were unrelated to postoperative morbidity. CONCLUSION: The LMA causes more sore throat and dysphagia but less jaw pain than the FM. Sore throat and dysphagia are more common with the LMA if the initial cuff volume is high. There are no differences in discomfort levels between males and females. However, these discomforts do not influence patient satisfaction after LMA or FM anesthesia.     

Sevoflurane versus propofol for anesthetic induction: a meta-analysis

We performed this meta-analysis to compare the characteristics of sevoflurane and propofol for the induction of routine anesthesia and for laryngeal mask airway (LMA) insertion. The variables assessed were 1) time to loss of consciousness, 2) incidence of apnea during induction, 3) induction complications, 4) time for successful LMA insertion, 5) success with LMA insertion on first attempt, 6) patient dissatisfaction, and 7) postoperative nausea and vomiting. MEDLINE, Embase, and the Cochrane library databases between January 1992 and October 1999 were reviewed for randomized, controlled trials comparing anesthetic induction between sevoflurane/nitrous oxide and propofol. Data from the 12 randomized, controlled studies were used for the meta-analysis. Sevoflurane induction was associated with a trend toward higher patient dissatisfaction and higher first-time success with LMA. Apnea was less common in the sevoflurane group. The incidence of postoperative nausea and vomiting was significantly more frequent in the sevoflurane group (P < 0.05). This effect was still present when all other variables, except the induction methods, were controlled. The other pooled variables did not show a significant difference between sevoflurane and propofol. Sevoflurane and propofol had similar efficacy for anesthetic induction. However, for routine outpatient surgery, propofol may still be the preferred induction anesthetic because of its favorable induction of anesthesia characteristics, high patient satisfaction, and less frequent incidence of postoperative nausea and vomiting. IMPLICATIONS: Sevoflurane and propofol had similar efficacy for anesthetic induction. However, for routine outpatient surgery, propofol may still be the preferred induction anesthetic because of its favorable induction of anesthesia characteristics, high patient satisfaction, and less frequent incidence of postoperative nausea and vomiting.     

A comparison of sevoflurane-propofol versus sevoflurane or propofol for laryngeal mask airway insertion in adults

In a prospective, randomized study, we investigated the incidence of successful insertion of laryngeal mask airway (LMA) at the first attempt and the incidence of side effects after LMA insertion using the combination of sevoflurane and propofol as compared with either sevoflurane or propofol alone for induction of anesthesia. Eighty-three unpremedicated ASA physical status I-II patients were anesthetized with a single vital capacity breath (VCB) of sevoflurane 8% supplemented with IV propofol 1.5 mg/kg, a single VCB of sevoflurane 8%, or IV propofol 3 mg/kg. The coinduction technique was associated with the most frequent incidence of successful LMA insertion at the first attempt (93.5%) than either sevoflurane alone (46%) or propofol alone (61.5%) (P < 0.001). Propofol-induced induction of anesthesia allowed the fastest insertion of LMA and was associated with the least frequent incidence of postoperative nausea and vomiting. However, this advantage of propofol was offset by a frequent incidence of pain on injection (69%) and the occurrence of movements during insertion of the LMA (50% in the propofol group versus 19% and 26% in the sevoflurane and sevoflurane-propofol groups, respectively; P < 0.05), as well as a more frequent incidence of apnea (84% in the propofol group versus 7% and 16% in the sevoflurane and sevoflurane-propofol groups, respectively; P < 0.001). The report shows that induction of anesthesia with sevoflurane-propofol combined provides a frequent incidence of successful LMA insertion at the first attempt that is associated with an infrequent incidence of apnea.     

Pharyngolaryngeal, Neck, and Jaw Discomfort after Anesthesia with the Face Mask and Laryngeal Mask Airway at High and Low Cuff Volumes in Males and Females

Background: There is controversy over (1) the relative incidence of sore throat between the face mask (FM) and laryngeal mask airway (LMA), (2) the efficacy of LMA intracuff pressure reduction as a mechanism for minimizing sore throat, and (3) the relative incidence of sore throat with the LMA between males and females. In a randomized double-blind study, the authors compared laryngopharyngeal, neck, and jaw discomfort with the FM and LMA at high and low cuff volumes in males and females.

Methods: Three hundred adult patients were randomly assigned to three equal-sized groups for airway management: (1) the FM, (2) the LMA with a fully inflated cuff (LMA-High), or (3) the LMA with a semi-inflated cuff (LMA-Low). Anesthesia was administered with propofol, nitrous oxide, oxygen, and isoflurane. In the FM group, a Guedel-type oropharyngeal airway and jaw thrust were used only if necessary. In the LMA groups, cuff inflation was achieved with either 15 or 30 ml for the size 4 (females) and 20 or 40 ml for the size 5 (males). The LMA was removed when the patient was awake. Patients were questioned 18-24 h postoperatively about surgical pain, sore throat, sore neck, sore jaw, dysphonia, and dysphagia, and about whether they were satisfied with their anesthetic.

Results: The incidence of sore throat was lower in the FM (8%) than the LMA-High (42%) and LMA-Low (20%) groups (both: P <= 0.02). The incidence of sore neck was higher for the FM (14%) than the LMA-High group (6%;P = 0.05) but similar to the LMA-Low group (8%). The incidence of sore jaw was higher in the FM (11%) than the LMA-High (3%) and LMA-Low (3%) groups (both:P = 0.02). There were no differences among groups for surgical pain or dysphonia. The incidence of dysphagia was lower in the FM (1%) than the LMA-High group (11%;P = 0.003), but similar to the LMA-Low group (1%). The incidence of sore throat and dysphagia was lower in the LMA-Low group than the LMA-High group for both males and females (all:P <= 0.04). There were no differences in discomfort levels between males and females in any group. Two patients from the FM group and one from the LMA-High group were not satisfied with their anesthetic. These complaints were unrelated to postoperative morbidity.     

Routine use of the intubating laryngeal mask airway results in increased upper airway morbidity

PURPOSE: The classic laryngeal mask airway (LMA) has a soft, silicone tube and the intubating laryngeal mask airway (ILM) has a rigid, silicone-coated steel tube. We compare postoperative pharyngolaryngeal morbidity in patients randomised to receive either device. METHODS: Sixty-five female patients (ASA physical status class I or II, aged 18-80 yr) undergoing balanced regional anesthesia for gynecological laparotomy expected to last one to two hours were randomly assigned for airway management with the LMA or ILM. Intracuff pressure was maintained at 60 cm H20. Postoperative pharyngolaryngeal morbidity (sore throat, difficulty swallowing, sore mouth, sore neck/jaw, hoarseness) was assessed at two, 24 and 48 hr by blinded investigators. RESULTS: The number of insertion attempts and duration of anesthesia was similar between groups. Sore throat was more common for the ILM at two hours (44 vs 15%, P=0.01), 24 hr (59 vs 21%, P=0.008) and 48 hr (34 vs 3%, P=0.005). Sore mouth was more common for the ILM at two hours (16 vs 0%, P=0.02) and 24 hr (12 vs 0%, P=0.04), but not at 48 hr (6 vs 3%). Difficulty swallowing was more common for the ILM at two hours (25 vs 0%, P=0.04), but not at 24 hr (31 vs 3%) and 48 hr (12 vs 9%). There were no differences in the incidence of sore jaw/neck (ILM, 3-12%; LMA, 0-3%) and hoarseness (ILM, 12-31%; LMA, 16-18%). There was no correlation between postoperative pharyngolaryngeal morbidity and duration of anesthesia. CONCLUSION: Pharyngolaryngeal morbidity is more common with the ILM than the LMA following anesthesia lasting one to two hours.     

Supreme喉罩用于腹腔镜手术患者气道管理的效果

目的 评价Supreme喉罩用于腹腔镜手术患者气道管理的效果.方法 择期全麻下行腹腔镜手术的患者120例,性别不限,年龄35～60岁,体重48～85 kg,ASA Ⅰ或Ⅱ级,Mallampatis Ⅰ～Ⅲ级,随机分为2组(n=60):Supreme喉罩组(S组)和气管插管组(T组).S组根据患者体重选择喉罩型号,麻醉诱导后置入喉罩,并经引流管放置胃管,T组在直接喉镜下行气管插管.记录气管插管或喉罩置入时间及置人情况;记录S组胃管置入状况和喉罩气道密封压,并行纤维支气管镜检查评分,以评价喉罩对位情况;记录术中SpO2、PrrCO2和气道峰压(Ppeak),记录拔除气管导管或喉罩后不良反应的发生情况;记录手术时间、麻醉时间、拔管时间和苏醒时间.结果 与T组比较,S组喉罩置入时间、拔管时间和苏醒时间缩短,拔除喉罩后低氧血症、呛咳、咽喉痛的发生率降低(P<0.05);两组均无返流误吸发生.各时点spO2、PETCO2、Ppeak均在正常范围内,组间比较差异无统计学意义(P>0.05).S组喉罩置入成功率和T组气管插管成功率比较差异无统计学意义(P>0.05),S组喉罩气道密封压为(25±4)cm H2O,喉罩对位准确率95%,胃管放置成功率100%.结论 Supreme喉罩通气效果好,气道密封性可靠,拔除后不良反应少,可安全有效地用于腹腔镜手术患者的全麻气道管理.     

i-gel喉罩用于腹腔镜胆囊手术患者气道管理的效果

目的 评价i-gel喉罩用于腹腔镜胆囊手术患者气道管理的效果.方法 择期全麻下拟行腹腔镜胆囊手术患者120例,性别不限,ASA分级Ⅰ或Ⅱ级,年龄34～62岁,体重45～90 kg,随机分为2组(n=60):ProSeal喉罩组(P组)和i-gel喉罩组(Ⅰ组).根据体重选择喉罩型号,麻醉诱导后置入喉罩,行机械通气,并经引流管放置胃管.记录喉罩置入次数、喉罩及胃管置入情况、纤支镜检查评分,测定喉罩密封压,观察术中口咽部漏气、低氧血症的发生情况.术中监测SpO2、PETCO2、气道峰压,观察拔除喉罩后恶心、呕吐、呛咳、声嘶、咽喉痛、返流误吸的发生情况,记录麻醉时间、手术时间、拔除喉罩时间及苏醒时间.结果 两组麻醉时间、手术时间、拔除喉罩时间及苏醒时间差异无统计学意义(P＞0.05).两组术中SpO2、PETCO2、气道峰压均在正常范围内.与P组比较,Ⅰ组喉罩首次置入成功率和纤支镜检查评分升高,喉罩置入时间缩短(P＜0.05).两组喉罩和胃管置入成功率均为100%;Ⅰ组和P组喉罩密封压比较差异无统计学意义(P＞0.05);Ⅰ组咽喉痛发生率低于P组(P＜0.05),恶心呕吐、呛咳发生率差异无统计学意义(P＞0.05),两组无一例发生声嘶、返流误吸.结论 i-gel喉罩易于置入,气道密封性可靠,通气效果好,不良反应少,可安全有效地用于腹腔镜胆囊手术患者的气道管理.     

Laryngeal mask cuff inflation at removal does not affect early postoperative laryngopharyngeal morbidity

PURPOSE: We assessed the effect of cuff inflation of the laryngeal mask airway at removal on sore throat, pharyngeal morbidity and airway complications. METHODS: In a prospective randomized trial, we used a standardized technique of anesthesia and of laryngeal mask insertion in 126 consecutive day-case patients. Postoperatively, on eye opening, the masks were removed either inflated (Group A) or deflated (Group B) and examined for blood by a blinded observer. Episodes of coughing, gagging, laryngospasm, hiccups and retching, and symptoms of sore throat and hoarseness were recorded by the same observer. RESULTS: Demographics were similar. Bloodstaining occurred in 21% of patients in Group A (n = 63) vs 13% in Group B (n = 63; P = 0.23); the incidence of sore throat was identical (19%). Group A experienced more hoarseness (22% vs 9%; P = 0.05). Overall airway complications did not differ between groups (19% vs 11%; P = 0.21). CONCLUSION: We conclude that removal of the laryngeal mask airway inflated does not reduce the incidence of sore throat, pharyngeal morbidity or airway complications.     

Comparison of sevoflurane with propofol for laryngeal mask airway insertion in adults

We performed a prospective, randomized, controlled trial to compare the quality and ease of laryngeal mask airway (LMA) insertion after either rapid inhaled sevoflurane or i.v. propofol induction of anesthesia. Seventy-six unpremedicated ASA physical status I or II patients were anesthetized with either a single vital capacity breath of sevoflurane 8% or i.v. propofol 3 mg/kg, which produced equally rapid loss of consciousness (40.5 +/- 13.9 vs 37.7 +/- 9.9 s; P > 0.05). The LMA was inserted more rapidly in patients in the propofol group (74 +/- 29 vs 127 +/- 35 s; P < 0.01) and required fewer attempts (1.2 vs 1.6; P < 0.05) than the sevoflurane group. There was a greater incidence of initially impossible mouth opening in the sevoflurane group (45% vs 21%; P < 0.05). Once mouth opening was possible, the degree of attenuation of laryngeal reflexes was similar. The overall incidence of complications related to LMA insertion, especially apnea (32% vs 0%; P < 0.01), was more frequent in the propofol group (82% vs 26%; P < 0.01). There were four failures of LMA insertion in the propofol group and none in the sevoflurane group. Both groups had stable hemodynamic profiles and good patient satisfaction. We conclude that sevoflurane vital capacity breath induction compares favorably with i.v. propofol induction for LMA insertion in adults. However, prolonged jaw tightness after the sevoflurane induction of anesthesia may delay LMA insertion. Implications: In this randomized, controlled trial, we compared the ease of insertion of the laryngeal mask airway in adults after induction of anesthesia with either a sevoflurane vital capacity breath technique or propofol i.v.. We conclude that sevoflurane compares favorably with propofol, although prolonged jaw tightness may delay laryngeal mask airway insertion.     

Does benzydamine hydrochloride applied preemptively reduce sore throat due to laryngeal mask airway?

Sore throat is a common postoperative complaint. We investigated whether preemptive benzydamine hydrochloride (BH) treatment could prevent sore throat due to a laryngeal mask airway (LMA) cuff inflated with air. One-hundred ASA status I-II patients who underwent general anesthesia were randomly divided into two groups. In the first group, four puffs of BH were applied to the pharynx 30 min before the operation and 5 min before the induction of anesthesia. Distilled water with a similar bottle was applied with the same protocol in the second group. Anesthetic induction was provided with propofol and fentanyl. The pressure of the LMA cuff inflated with room air was measured after the first adjustment and after 30, 60, and 90 min of inflation in both groups. At the end of operation, the LMA was removed after the recovery of spontaneous breathing. After the operation, patients were asked about sore throat symptoms at the first, second, and fourth hours. There were no significant differences between groups for cuff pressures, cuff volumes, analgesic doses, or operation times. However, sore throat symptoms were significantly less severe for the BH group during both resting and swallowing. In conclusion, preemptive topical BH may decrease the incidence of sore throat due to LMA use.     

Postoperative sore throat: effect of oropharyngeal airway in orotracheally intubated patients

The incidence of postoperative sore throat was evaluated prospectively in 203 orotracheally intubated patients undergoing general anesthesia for surgical procedures. Patients were randomly assigned to have either a plastic oropharyngeal airway or a gauze bite-block in place during the operation and were evaluated for the occurrence of postoperative sore throat by questionnaire the day after surgery. The incidence of postoperative sore throat was 35.2% in the oropharyngeal airway group and 42.5% in the gauze bite-block group, not a statistically significant difference (P greater than 0.05). The incidence of postoperative sore throat was significantly higher when blood was noted on the airway instruments (64.5%) than when it was not (30.9%) (P less than 0.01). There was an association, although not statistically significant, between the incidence of postoperative sore throat and intubation by an anesthesia resident with less than 1 yr experience (P = 0.064). The data from this study indicate that the intraoperative use of hard plastic oropharyngeal airways, compared with the use of soft gauze bite-blocks, does not increase the incidence of postoperative sore throat. These data also suggest that pharyngeal trauma may contribute significantly to the development of postoperative sore throat. We suggest that aggressive oropharyngeal suctioning may contribute to this pharyngeal trauma.     

Einfluß der Kehlkopfmaske auf postoperatives Erbrechen und Halsschmerzen bei Kindern

100 ASA I and II children, aged 4 to 14 years, and scheduled for strabismus surgery, were randomly assigned to one of the following groups: group 1 (n=50): endotracheal tube, group 2 (n=50): laryngeal mask airway. Apart from airway management, the anaesthesiological procedures were identical in both groups: induction with 2–3 mg/kg propofol, 0.02 mg/kg alfentanil, 0.05 mg/kg vecuronium, and 0.01 mg/kg atropine. After endotracheal intubation or insertion of the laryngeal mask, anaesthesia was continued with 6–15 mg/kg·h propofol and 10–30 μg/kg·h alfentanil. All patients were ventilated with N₂O/O₂ (2:1). No antiemetics were given, gastric contents were not aspirated. Postoperative nausea and vomiting (PONV) were recorded by 24 h, the incidence of sore throats was recorded 8, 12, and 24 h post-operatively. Results. The incidence of PONV was higher in group 1 (vomiting 48% vs 32%), nausea 28% vs 16% n.s.). Group 1 children had a higher incidence of sore throats (20% vs. 12%, n.s.), of a “lump in the throat” (10% vs 4%, n.s.), hoarseness (24% vs 0%, p<0.001) and dysarthria (10% vs 4%, n.s.). Conclusions. In children undergoing strabismus surgery, the laryngeal mask airway was superior to the endotracheal tube in terms of PONV and was associated with fewer local complications such as sore throat.     

Prospective Randomized Controlled Trial on the Use of Flexible Reinforced Laryngeal Mask Airway (LMA) During Total Thyroidectomy: Effects on Postoperative Laryngopharyngeal Symptoms

Background

Sore throat, hoarseness, dysphagia, and cough are common laryngopharyngeal discomforts after thyroidectomy. The incidence and severity of laryngopharyngeal symptoms after the use of a flexible reinforced laryngeal mask airway (LMA) were compared with those that occur after the use of a plain endotracheal tube in patients after thyroidectomy.

Methods

Seventy-six patients scheduled for total thyroidectomy were randomized into a plain endotracheal tube group (group E) or a flexible reinforced LMA group (group L). Total intravenous anesthesia (propofol and remifentanil) was used for maintenance of anesthesia. Hemodynamic variables were recorded during induction of anesthesia. The incidence and severity (100-point numerical rating scales) of laryngopharyngeal symptoms, including sore throat, hoarseness, dysphagia, and cough, were assessed at 1, 24, and 48 h after surgery.

Results

All patients were placed successfully with an endotracheal tube or a flexible reinforced LMA. The postoperative incidence and severity of sore throat (25 vs. 33 at 24 h, p = 0.035, 17 vs. 28 at 48 h, p = 0.017; 50 [0–100] vs. 80 [20–100] at 1 h, p = 0.002; 30 [0–80] vs. 50 [0–100] at 24 h, p < 0.001; 0 [0–40] vs. 30 [0–90] at 48 h, p < 0.001) and hoarseness were lower in group L than in group E. At 48 h postoperatively, dysphagia (p = 0.005) and cough (p = 0.028) occurred less frequently in group L than in group E patients.

Conclusion

A flexible reinforced LMA placed during surgery decreases the incidence and severity of laryngopharyngeal symptoms and is a feasible anesthetic tool compared with a conventional endotracheal tube for thyroidectomy.     

A multicenter study comparing the ProSeal and Classic laryngeal mask airway in anesthetized, nonparalyzed patients

BACKGROUND: The laryngeal mask airway ProSeal (PLMA), a new laryngeal mask device, was compared with the laryngeal mask airway Classic (LMA) with respect to: (1) insertion success rates and times; (2) efficacy of seal; (3) fiberoptically determined anatomic position; (4) orogastric tube insertion success rates and times; (5) total intraoperative complications; and (6) postoperative sore throat in nonparalyzed adult patients undergoing general anesthesia, hypothesizing that these would be different. METHODS: Three hundred eighty-four nonparalyzed anesthetized adult patients (American Society of Anesthesiologists physical status I-II) were randomly allocated to the PLMA or LMA for airway management. In addition, 50% of patients were randomized for orogastric tube placement. Unblinded observers collected intraoperative data, and blinded observers collected postoperative data. RESULTS: First-attempt insertion success rates (91 vs. 82%, P = 0.015) were higher for the LMA, but after three attempts success rates were similar (LMA, 100%; PLMA, 98%). Less time was required to achieve an effective airway with the LMA (31 +/- 30 vs. 41 +/- 49 s; P = 0.02). The PLMA formed a more effective seal (27 +/- 7 vs. 22 +/- 6 cm H2O; P < 0.0001). Fiberoptically determined anatomic position was better with the LMA (P < 0.0001). Orogastric tube insertion was more successful after two attempts (88 vs. 55%; P < 0.0001) and quicker (22 +/- 18 vs. 38 +/- 56 s) with the PLMA. During maintenance, the PLMA failed twice (leak, stridor) and the LMA failed once (laryngospasm). Total intraoperative complications were similar for both groups. The incidence of postoperative sore throat was similar. CONCLUSION: In anesthetized, nonparalyzed patients, the LMA is easier and quicker to insert, but the PLMA forms a better seal and facilitates easier and quicker orogastric tube placement. The incidence of total intraoperative complications and postoperative sore throat are similar.     

Laryngo-pharyngeal complaints after use of the laryngeal mask airway

PURPOSE: To compare the incidence of dysphagia, dysphonia and sore throat following anesthesia, using the laryngeal mask airway (LMA), among patients receiving intermittent positive-pressure ventilation (IPPV) and those breathing spontaneously (SV) and with two different concentrations of nitrous oxide (N2O) in oxygen. METHODS: In a prospective trial, 120 patients (ASA I-III, 16-70 yr, > 60 kg) undergoing minor peripheral surgery were randomised into four groups with respect to type of ventilation and N2O concentration (50% or 66%) received. Cuff pressure measurements were monitored continuously. Twenty-four hours after surgery, patients were questioned for sore throat, dysphagia and dysphonia. RESULTS: At 30 min post-LMA insertion, increases in cuff pressure were 35.2+/-17.1 mmHg (22.8%) vs 50.1+/-16.3 mmHg (32.7%) in patients breathing 50 and 66% N2O, respectively (P < 0.01). There were no differences in cuff pressure increment between patients in the SV and IPPV groups. Cuff pressure values at the end of surgery depended on the duration of surgery and on the concentrations of N2O. The overall incidence of postoperative discomfort at 24 hr was dysphagia 11%, dysphonia 11% and sore throat 28.8%. Only two patients reported sore throat as more than mild. There was no relationship between cuff pressure and laryngo-pharyngeal complaints. The incidence of dysphonia in the groups receiving IPPV was higher than that in the groups with spontaneous ventilation (17.2 vs 5%, P < 0.05). CONCLUSION: Post-operative discomfort is related to the type of ventilation but not to variation in LMA cuff pressure.     

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 low-dose mivacurium to facilitate insertion of the laryngeal mask airway

Ninety patients were assigned randomly in a double-blind manner to receive 0.9% sodium chloride, mivacurium 0.04 mg.kg⁻¹ or mivacurium 0.08 mg.kg⁻¹ intravenously, followed by propofol 2.5 mg.kg⁻¹. A laryngeal mask airway (LMA) was inserted 90 s later. The LMA was positioned correctly during the first attempt in 87% of patients and this was not significantly altered by the use of mivacurium. However, mivacurium decreased the incidence of swallowing, coughing, movement and laryngospasm (p < 0.05). LMA insertion was graded as easy in 88% of patients who had mivacurium, compared with 50% in patients who had propofol alone (p < 0.05). The conditions during LMA insertion were similar after 0.04 or 0.08 mg.kg⁻¹ of mivacurium. Patients were apnoeic for a mean (SD) time of 0.67 (0.72) min after propofol alone, compared with 1.72 (1.06) min and 3.05 (1.36) min in patients who also received mivacurium 0.04 and 0.08 mg.kg⁻¹, respectively (p < 0.01). Patients who received mivacurium had a lower incidence of postoperative sore throat (24–30% vs. 53%) (p < 0.05). In conclusion, low-dose mivacurium facilitates LMA insertion and decreases the incidence of postoperative sore throat.     

Comparison of disposable and reusable laryngeal mask airways in spontaneously ventilating adult patients

Recent studies have indicated that despite stringent sterilization processes, the reusable silicone laryngeal mask airway (LMA) has the potential for disease transmission through residual biological debris. As a result, a polyvinyl chloride (PVC) disposable LMA has been introduced. This randomized trial involved 138 spontaneously ventilating adult patients who underwent elective surgery requiring airway management with an LMA to determine whether there is a clinical difference between the disposable Portex LMA (PLMA) and the standard reusable LMA in terms of ease of insertion, intra-operative cuff pressures and postoperative incidence of sore throat. There was no significant difference in first attempt insertion success rates (79% vs 84%) or difference in the incidence of postoperative sore throat observed between the two groups. Cuff pressure increases with nitrous oxide anaesthesia were significantly larger with the reusable LMA. The disposable PLMA provided a suitable airway in spontaneously ventilating patients without the risk of disease transmission inherent in a reusable device.