A comparison of the proseal laryngeal mask airway, the laryngeal tube S and the oesophageal-tracheal combitube during routine surgical procedures

Regurgitation and pulmonary aspiration during cardio-pulmonary resuscitation (CPR) with a laryngeal tube: A pilot crossover human cadaver study

Background

High-quality chest compressions are imperative for Cardio-Pulmonary-Resuscitation (CPR). International CPR guidelines advocate, that chest compressions should not be interrupted for ventilation once a patient’s trachea is intubated or a supraglottic-airway-device positioned. Supraglottic-airway-devices offer limited protection against pulmonary aspiration. Simultaneous chest compressions and positive pressure ventilation both increase intrathoracic pressure and potentially enhances the risk of pulmonary aspiration. The hypothesis was, that regurgitation and pulmonary aspiration is more common during continuous versus interrupted chest compressions in human cadavers ventilated with a laryngeal tube airway.

Methods

Twenty suitable cadavers were included, and were positioned supine, the stomach was emptied, 500 ml of methylene-blue-solution instilled and laryngeal tube inserted. Cadavers were randomly assigned to: 1) continuous chest compressions; or, 2) interrupted chest compressions for ventilation breaths. After 14 minutes of the initial designated CPR strategy, pulmonary aspiration was assessed with a flexible bronchoscope. The methylene-blue-solution was replaced by 500 ml barium-sulfate radiopaque suspension. 14 minutes of CPR with the second designated ventilation strategy was performed. Pulmonary aspiration was then assessed with a conventional chest X-ray.

Results

Two cadavers were excluded for technical reasons, leaving 18 cadavers for statistical analysis. Pulmonary aspiration was observed in 9 (50%) cadavers with continuous chest compressions, and 7 (39%) with interrupted chest compressions (P = 0.75).

Conclusion

Our pilot study indicate, that incidence of pulmonary aspiration is generally high in patients undergoing CPR when a laryngeal tube is used for ventilation. Our study was not powered to identify potentially important differences in regurgitation or aspiration between ongoing vs. interrupted chest compression. Our results nonetheless suggest that interrupted chest compressions might better protect against pulmonary aspiration when a laryngeal tube is used for ventilation.

Two Cases of Bilateral Vocal Fold Mobility Impairment After LMA Use In 7 Months

OBJECTIVES

To increase awareness of vocal fold mobility impairment secondary to laryngeal mask airway (LMA) use in the operating room.

METHODS

We report 2 cases of bilateral vocal fold mobility impairment after LMA use within 7 months of each other. One patient is a 52-year-old female who developed this complication after orthopedic elbow surgery. The second case is a 75-year-old male who presented after undergoing inguinal hernia repair.

RESULTS

The patient from the first case required a 7-day hospital stay in the SICU due to airway compromise with spontaneous resolution of right-sided vocal fold immobility and improvement of symptoms. The 75-year-old male required direct laryngoscopy and bilateral true vocal fold injection medialization to correct his bilateral vocal fold paresis causing dysphonia and aspiration of liquids.

CONCLUSIONS

Bilateral vocal fold immobility secondary to LMA use is likely an underreported phenomenon of which otolaryngologists and anesthesiologists should be aware. Presentation may be severe, requiring hospitalization or operative intervention.

Insertion Success of the Laryngeal Tube in Emergency Airway Management

Background. Emergency airway management (AM) is a priority when resuscitating critically ill or severely injured patients. The goal of this study was to determine the success rates of LT insertion during AM. Methods. Studies that included LT first-pass insertion (FPI) and overall-pass insertion (OPI) success by emergency medical services and in-hospital providers performing AM for emergency situations as well as for scheduled surgery published until July 2014 were searched systematically in Medline. Results. Data of 36 studies (n = 1,897) reported a LT FPI success by physicians of 82.5% with an OPI success of 93.6% (p < 0.001). A cumulative analysis of all 53 studies (n = 3,600) led to FPI and OPI success of 80.1% and 92.6% (p < 0.001), respectively. The results of 26 studies (n = 2,159) comparing the LT with the laryngeal mask airway (LMA) demonstrated a FPI success of 77.0 versus 78.7% (p = 0.36) and an OPI success of 92.2 versus 97.7% (p < 0.001). Conclusion. LT insertion failed in the first attempt in one out of five patients, with an overall failure rate in one out of 14 patients. When compared with the LT, the LMA had a cumulative 5.5% better OPI success rate.

Comparison between supraglottic airway devices and endotracheal tubes in patients undergoing laparoscopic surgery: A systematic review and meta-analysis

BACKGROUND

Comparisons between the efficacies of supraglottic airway devices (SGAs) and endotracheal tubes (ETTs) in patients undergoing laparoscopic surgeries have yielded conflicting results. Therefore, in this meta-analysis, we compared the clinical performance and incidence of complications between SGAs and ETT intubation in laparoscopic surgery.

METHODS

A comprehensive search was conducted using MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and Google Scholar to identify randomized controlled trials that compared SGAs with ETTs in laparoscopic surgery.

RESULTS

In total, 1433 patients from 17 studies were included in the final analysis. SGAs and ETTs showed no difference in insertion success rate on the first attempt (relative risk [RR] 1.01, 95% confidence interval [CI] 0.99-1.03), insertion time (standardized mean difference 1.57, 95% CI -3.74 to 0.61), and oropharyngeal leak pressure (OLP) (mean difference -2.54, 95% CI -7.59 to 2.50). The incidence of desaturation (RR 3.65, 95% CI 1.39-9.62), gastric insufflations (RR 0.90, 95% CI 0.48-1.71), regurgitation (RR 0.98, 95% CI 0.02-49.13), and aspiration (RR 0.99, 95% CI 0.01-78.4) also showed no intergroup differences. However, the incidence of laryngospasm (RR 3.12, 95% CI 1.29-7.52), cough at removal (RR 6.68, 95% CI 4.70-9.48), dysphagia (RR 1.47, 95% CI 1.12-1.95) or dysphonia (RR 4.41, 95% CI 1.25-15.55), sore throat (RR 1.60, 95% CI 1.33-1.93), and hoarseness (RR 1.53, 95% CI 1.29-1.81) was higher in the ETT group than in the SGA group.

CONCLUSIONS

The incidence of laryngospasm, cough at removal, dysphagia or dysphonia, sore throat, and hoarseness were higher in the ETT group than in the SGA group. However, the groups showed no differences in the rate of insertion success on the first attempt, insertion time, OLP, and other complications. Therefore, SGAs might be clinically more useful as effective airways in laparoscopic surgery.

Evaluation of six different airway devices regarding regurgitation and pulmonary aspiration during cardio-pulmonary resuscitation (CPR) - A human cadaver pilot study

BACKGROUND

Chest compressions and ventilation are lifesaving tasks during cardio-pulmonary resuscitation (CPR). Besides oxygenation, endotracheal intubation (ETI) during CPR is performed to avoid aspiration of gastric contents. If intubation is difficult or impossible, supraglottic airway devices are utilized. We tested six different airway devices regarding their potential to protect against regurgitation and aspiration during CPR in a randomized experimental human cadaver study.

METHODS

Five-hundred ml of 0.01% methylene-blue-solution were instilled into the stomach of 30 adult human cadavers via an oro-gastric tube. The cadavers were then randomly assigned to one of six groups, resulting in 5 cadavers in each group. Airway management was performed with either bag-valve ventilation, Laryngeal Tube, EasyTube, Laryngeal Mask (Classic), I-Gel, or ETI. Thereafter 5min of CPR were performed according to the 2010 Guidelines of the European Resuscitation Council. Pulmonary aspiration was defined as the presence of methylene-blue-solution below the vocal cords or the ETI cuff as assessed by fiber-optic bronchoscopy.

RESULTS

Thirty cadavers were included (14 females, 16 males). Aspiration was detected in three out of five cadavers receiving bag-valve ventilation and in two out of five intubated with LMA or I-Gel. In cadavers intubated with the LT, aspiration occurred in one out of five cases. No aspiration could be detected in cadavers intubated with ETI and EasyTube.

CONCLUSION

This study provides experimental evidence that, during CPR, ETI offers superior protection against regurgitation and pulmonary aspiration of gastric contents than supraglottic airway devices or bag-valve ventilation.

Feasibility and speed of insertion of seven supraglottic airway devices under simulated airway conditions

OBJECTIVES

Endotracheal intubation (ETI) is considered the gold standard for protecting the airway. Alternative devices for airway protection have been developed that can be used by untrained personnel, by those with less experience, and for when ETI is not possible. The main goals of our study were to evaluate the success rate and speed of insertion of different supraglottic airway devices and to determine whether the devices could be properly inserted under simulated critical conditions.

METHODS

Fifty medical students used an airway simulation trainer (Laerdal SimMan 3G) to assess the success rate and time used to insert seven different supraglottic airway devices under simulated physiologic and pathologic conditions in two different runs.

RESULTS

Although all airway devices could be inserted without problems, only the Combitube and the EasyTube could be successfully inserted in simulations of trismus, limited mobility of the cervical spine, or a combination of pathologic conditions such as trismus plus limited mobility of the spine and trismus plus tongue edema. The insertion time was significantly longer with LMA Unique, Fastrach, and I-Gel devices in both the first and second runs.

CONCLUSION

The Combitube and the EasyTube were most easily inserted under simulated conditions such as trismus, limited mobility of the cervical spine, and combined pathologic conditions. Although all devices are useful for establishing an airway by nontrained medical students in standard simulations, we suggest that the Combitube and the EasyTube may offer advantages in difficult airway situations.

Comparison of endotracheal intubation, combitube, and laryngeal mask airway between inexperienced and experienced emergency medical staff: A manikin study

Background:

Emergency Medical Service (EMS) personnel manage the airway, but only a group of them are allowed to engage in Endotracheal Intubation (ETI). Our purpose was to evaluate if the use of laryngeal mask airway (LMA) or Combitube can be used by inexperienced care providers.

Materials and Methods:

A randomized, prospective manikin study was conducted. Fifty-nine participants were randomly assigned into two groups. Experienced group included 16 paramedics, eight anesthetic-technicians, and inexperienced group included 27 Emergency Medical Technician-Basic (EMT-B) and eight nurses. Our main outcomes were success rate and time to airway after only one attempt.

Results:

Airway success was 73% for ETI, 98.3% for LMA, and 100% for Combitube. LMA and Combitube were faster and had greater success than ETI (P = 0.0001). Inexperienced had no differences in time to securing LMA compared with experienced (6.05 vs. 5.4 seconds, respectively, P = 0.26). One failure in inexperienced, and no failure in experienced group occurred to secure the LMA (P = 0.59). The median time to Combitube placement in experienced and inexperienced was 5.05 vs. 5.00 seconds, P = 0.65, respectively. Inexperienced and experienced groups performed ETI in 19.15 and 17 seconds, respectively (P = 0.001). After the trial, 78% preferred Combitube, 15.3% LMA, and 6.8% ETI as the device of choice in prehospital setting.

Conclusion:

Time to airway was decreased and success rate increased significantly with the use of LMA and combitube compared with ETI, regardless of the experience level. This study suggests that both Combitube and LMA may be acceptable choices for management of airway in the prehospital setting for experienced and especially inexperienced EMS personnel.

Comparison of combitube, easy tube and tracheal tube for general anesthesia

Background & Aims:

The Combitube^® and EasyTube™ enable effective ventilation whether placed in the trachea or esophagus and can be used in prehospital settings, as well as in “Cannot Ventilate Cannot Intubate” situations in the operating room. Whether they can be continued to provide general anesthesia, if required, is not established. Thus the efficacy of Combitube and EasyTube was evaluated and compared with the tracheal tube for general anesthesia using controlled ventilation.

Materials and Methods:

Combitube, EasyTube and tracheal tubes were used in 30 patients each to secure the airway in a randomized controlled manner. Ventilatory parameters were measured along with hemodynamic variables, and characteristics related to device placement.

Results:

There was no significant difference in the various ventilatory parameters including minute ventilation requirement to maintain eucapnia amongst the three groups at any time point. There was no hypoxia or hypercarbia in any patient at any time. Placement of EasyTube was more difficult (P = 0.01) as compared with both Combitube and tracheal tube. EasyTube and Combitube resulted in higher incidence of minor trauma than with a tracheal tube (P = 0.00).

Conclusion:

Combitube and EasyTube may be continued for general anesthesia in patients undergoing elective nonlaparoscopic surgeries of moderate duration, if placed for airway maintenance. Given the secondary observations regarding placement characteristics of the airway devices, it, however cannot be concluded that the devices are a substitute for endotracheal tube for airway maintenance per se, unless specifically indicated

Intravenous dexamethasone versus ketamine gargle versus intravenous dexamethasone combined with ketamine gargle for evaluation of post-operative sore throat and hoarseness: A randomized, placebo-controlled, double blind clinical trial

BACKGROUND

Sore throat and hoarseness are the most frequent subjective complaints after tracheal intubation for general anesthesia. We conducted a prospective, randomized, double-blind, placebo controlled study to evaluate the efficacy of intravenous (IV) dexamethasone plus ketamine gargle for reducing the incidence and severity of post-operative sore throat (POST) and hoarseness.

MATERIALS AND METHODS

140 patients (aged 16-65 year) scheduled for elective surgery were enrolled. Patients were randomly allocated into four groups of 35 subjects each: Group K, gargled 40 mg ketamine in 30 ml saline; Group D, were infused 0.2 mg/kg IV dexamethasone; Group KD, gargled 40 mg ketamine in 30 ml saline plus 0.2 mg/kg IV dexamethasone; Group P (placebo) that received saline (gargle and IV). POST was graded at 0, 2, 4, 8, 16 and 24 h after operation on a four-point scale (0-3).

RESULTS

The incidence and severity of POST were significantly lower in Group KD, compared with the other groups at all times after tracheal extubation for up to 24 h (P < 0.05). Also the incidence and severity of hoarseness were significantly lower in each Groups of KD and K and D compared with group placebo (P < 0.05).

CONCLUSION

The prophylactic use of 0.2 mg/kg of IV dexamethasone plus ketamine gargle significantly reduced the incidence and severity of POST compared with using each of these drugs alone or using placebo.

Comparison of the size 3 and size 4 ProSeal™ laryngeal mask airway in anesthetized, non-paralyzed women: a randomized controlled trial

PURPOSE

Based on experimental results, various authors have advocated a size 4 ProSeal™ laryngeal mask airway (PLMA) in preference to a size 3 PLMA for women given a neuromuscular blocking agent because the larger size provided a better airway seal. However, spontaneously breathing patients may be ventilated adequately with a lower seal pressure than that needed for mechanical ventilation. Therefore, a smaller size might be preferable as its reduced bulk possibly induces less mucosal damage in non-paralyzed patients.

METHODS

A total of 152 females undergoing general anesthesia for short outpatient gynecological surgeries were randomly allocated in equal numbers to insertion of a size 3 or 4 PLMA. The insertion time, success rate, seal pressure, hemodynamic variables, and complications, such as blood staining and sore throat, were evaluated.

RESULTS

The incidence of blood staining was lower with the size 3 PLMA compared to the size 4 PLMA (18 vs. 36 %; P = 0.028). Compared with the size 3 LMA, the size 4 PLMA resulted in higher fluctuations in both blood pressure (P = 0.003) and heart rate (P = 0.01). The insertion time was shorter with the size 3 PLMA (9 vs. 16 s; P < 0.001). The airway seal pressure with the size 3 PLMA, although lower than that of the size 4 PLMA (23 vs. 28 cmH2O; P = 0.001), was sufficient for spontaneous ventilation.

CONCLUSIONS

Due to the reduced incidence of mucosal injury and greater hemodynamic stability, the size 3 PLMA may be preferable to the size 4 PLMA for non-paralyzed females.

Extraglottic airway devices: A review

Extraglottic airway devices (EAD) have become an integral part of anesthetic care since their introduction into clinical practice 25 years ago and have been used safely hundreds of millions of times, worldwide. They are an important first option for difficult ventilation during both in-hospital and out-of-hospital difficult airway management and can be utilized as a conduit for tracheal intubation either blindly or assisted by another technology (fiberoptic endoscopy, lightwand). Thus, the EAD may be the most versatile single airway technique in the airway management toolbox. However, despite their utility, knowledge regarding specific devices and the supporting data for their use is of paramount importance to patient's safety. In this review, number of commercially available EADs are discussed and the reported benefits and potential pitfalls are highlighted.

Comparison of Propofol and Ketamine-Propofol Mixture (Ketofol) on Laryngeal Tube-Suction II Conditions and Hemodynamics: A Randomized, Prospective, Double-Blind Trial

OBJECTIVE

The aim of our study is to compare the effect of ketamine-propofol mixture (ketofol) and propofol on the laryngeal tube-Suction II (LTS II) insertion conditions and hemodynamics.

METHODS

Eighty American Society of Anesthesiologists class 1 and 2 patients were divided into 2 random groups to receive either 1 µg/kg remifentanil and propofol 2 mg/kg in Group P (n = 40), or 1 µg/kg remifentanil and ketofol (using a 1:1 single syringe mixture of 5 mg/mL ketamine and 5 mg/mL propofol) in Group K (n = 40) before induction of anesthesia. After induction, LTS II was inserted. Heart rate and noninvasive blood pressure were recorded before induction of anesthesia (t0); immediately following induction (t1); immediately after LTS II insertion (t2); and 3 minutes (t3), 5 minutes (t4), and 10 (t5) minutes after LTS II insertion. Conditions of insertion of LTS II were assessed and scored 1 to 3 using 6 variables as follows: mouth opening, swallowing, coughing, head and body movements, laryngospasm, and ease of LTS II insertion by the same experienced anesthesiologist who did not know the agents. LTS II insertion summed score was prepared depending upon these variables.

RESULTS

In regard to LTS II insertion summed score, Group K was more favorable than Group P (P < 0.05). Apnea duration was longer in Group P (385.0 seconds [range = 195.0-840.0 seconds]) compared with Group K (325.50 seconds [range = 60.0-840.0 seconds]) but this was not statically significant. The heart rate values were significantly lower at all measurement intervals in both groups compared with the baseline values (P < 0.05). There was no difference in heart rate between Group P and Group K. The mean arterial pressure values were significantly lower at all measurement intervals in Group P compared with baseline values (P < 0.05). In Group K, the mean arterial pressure values were significantly lower at all measurement intervals compared with the baseline values, except t2 (P < 0.05). There was a significant difference between Group P and Group K in terms of mean arterial pressure at t3 (P < 0.05).

CONCLUSIONS

We found that ketofol provided better insertion summed score for LTS II than propofol, with minimal hemodynamic changes.

Failure to ventilate with supraglottic airways after drowning

We report the failure of an i-gel and an Ambu AuraOnce supraglottic airway to ventilate a drowning victim. Failure was attributed to changes in lung physiology following submersion and inhalation of water that may have required ventilation pressures up to 40 cmH2O to treat the victim's hypoxaemia. The ease of use and rapid insertion of supraglottic airways without interrupting cardiac compression has prompted recommendations for their use during resuscitation. The relatively low leak pressures attainable from many supraglottic airways, however may cause inadequate lung ventilation and entrainment of air into the stomach when these devices are used in drowning victims.

Hands-off time during insertion of six airway devices during cardiopulmonary resuscitation: a randomised manikin trial

INTRODUCTION

Cardiopulmonary resuscitation (CPR) guidelines recommend limiting interruptions of chest compressions because prolonged hands-off (i.e., non-compression) time compromises tissue perfusion. 2010 European Resuscitation Council guidelines suggest that chest compressions should be paused less than 10 s during airway device insertion.

METHODS

With approval of the local ethics committee of the Medical University of Vienna and written informed consent, we recruited 40 voluntary emergency medical technicians, none of whom had advanced airway management experience. After a standardised audio-visual lecture and practical demonstration, technicians performed airway management with each six airway devices (endotracheal tube, Combitube, EasyTube, laryngeal tube, Laryngeal Mask Airway, and I-Gel) during on-going chest compressions in a randomised sequence on a Resusci Anne Advanced Simulator. Data were analysed using a mixed-effects model accounting for the repeated measurements and pair-wise comparisons among the airway devices.

RESULTS

The hands-off time associated with airway management using an endotracheal tube (including all intubation attempts) was 48 s (95% confidence interval: 43-53). The hands-off time for airway management using a laryngeal tube was 8.4 (3.4-16.4) s, Combitube 10.0 (4.9-15.1) s, EasyTube 11.4 (6.4-16.4) s, LMA 13.3 (8.2-18.3) s and for I-Gel 15.9 (10.8-20.9) s. Hands-off time was significantly longer with the conventional endotracheal tube than with any of the other airway systems. Only a third of the technicians successfully inserted an endotracheal tube whereas all of them successfully positioned each supraglottic device.

CONCLUSION

Supraglottic devices appear to be a reasonable emergency airway management strategy, even for inexperienced personnel.

Performance and skill retention of intubation by paramedics using seven different airway devices--a manikin study

INTRODUCTION

Endotracheal intubation (ETI) is the most widespread method for emergency airway management. Several studies reported that ETI requires considerable skill and experience and if performed incorrectly, may result in serious adverse events. Unrecognized tube misplacement or oesophageal intubation is associated with high prehospital morbidity. This study investigates the usability of supraglottic airway devices compared to ETI and the skill retention of 41 previously inexperienced paramedics following training using a manikin model.

METHODS

41 paramedics participated in this study. None had prior experience in airway management, apart from bag-valve ventilation. After a standardised audio-visual lecture lasting 45min, the paramedics participated in a practical demonstration using the advanced patient simulator SimMan(®) (Laerdal Medical, Stavanger, Norway). Afterwards, paramedics were instructed to perform airway-management using seven different techniques to secure the airway (ETI, Laryngeal mask unique [LMA], Proseal, Laryngeal tube disposable [LT-D(®)], I-Gel(®), Combitube(®), and EasyTube(®)) following a randomized sequence. Participants underwent reassessment after 3 months without any further training or practice in airway-management.

RESULTS

During the initial training session, ETI was successfully performed in 78% of cases, while 3 months later the success rate was 58%. For the supraglottic airway devices, five out of six were successfully used by all paramedics at both time points, the exception being Proseal(®). Our data show successful skill retention (success rate: 100%) after 3 months for five out of six supraglottic airway devices. Time to ventilation (T3) was significantly less for LMA, LT-D(®) and I-Gel(®) at all time points compared to ETI.

CONCLUSION

ETI performed by inexperienced paramedics is associated with a low success rate. In contrast, supraglottic airway devices like LMA, LT-D(®), I-Gel(®), Combitube(®) and EasyTube(®) are fast, safe and easy-to-use. Within the limitations of a manikin-study, this study suggests that inexperienced medical staff might benefit from using supraglottic airway devices for emergency airway management.

Anesthesia in prehospital emergencies and in the emergency department

PURPOSE OF REVIEW

Recently, notable progress has been made in the field of anesthesia drugs and airway management.

RECENT FINDINGS

Anesthesia in prehospital emergencies and in the emergency department is reviewed and guidelines are discussed.

SUMMARY

Preoxygenation should be performed with high-flow oxygen delivered through a tight-fitting face mask with a reservoir. Ketamine may be the induction agent of choice in hemodynamically unstable patients. The rocuronium antagonist sugammadex may have the potential to make rocuronium a first-line neuromuscular blocking agent in emergency induction. Experienced healthcare providers may consider prehospital anesthesia induction. Moderately experienced healthcare providers should optimize oxygenation, hasten hospital transfer and only try to intubate a patient whose life is threatened. When intubation fails twice, ventilation should be performed with an alternative supraglottic airway or a bag-valve-mask device. Lesser experienced healthcare providers should completely refrain from intubation, optimize oxygenation, hasten hospital transfer and ventilate patients only in life-threatening circumstances with a supraglottic airway or a bag-valve-mask device. Senior help should be sought early. In a 'cannot ventilate-cannot intubate' situation, a supraglottic airway should be employed and, if ventilation is still unsuccessful, a surgical airway should be performed. Capnography should be used in every ventilated patient. Clinical practice is essential to retain anesthesia and airway management skills.

Supraglottic airway devices in the ambulatory setting

Supraglottic airway devices (SGAs) offer certain advantages over endotracheal intubation, making them particularly well suited for the specific demands of outpatient anesthesia. Patients may tolerate the placement and maintenance of an SGA at a lower dose of anesthetic than that needed for an endotracheal tube; neuromuscular blocking agents are rarely necessary for airway management with an SGA; the incidence of airway morbidity is lower with SGAs than with endotracheal tubes; and SGAs may facilitate faster recovery and earlier discharge of patients. Two limitations of SGAs are incomplete protection against aspiration of gastric contents and inadequate delivery of positive pressure ventilation. Newer variants of the original laryngeal mask airway, the LMA Classic (LMA North America, Inc), as well as an array of other recently developed SGAs, aim to address these limitations. Their utility and safety in specific patient populations (eg, the morbidly obese) and during certain procedures (eg, laparoscopic surgery) remain to be determined.

Disposable versus reusable laryngeal tube suction for ventilation in patients undergoing laparoscopic cholecystectomy

BACKGROUND AND OBJECTIVE

The laryngeal tube suction II (LTS-II) is a recent version of reusable supraglottic airway devices allowing gastric drainage. In this prospective, randomized study we compared insertion and ventilation of disposable LTS-II (LTS-D) with reusable type (LTS-II) for airway management under conditions with elevated intra abdominal pressure induced by capnoperitoneum.

METHODS

60 ASA I and II patients undergoing elective laparoscopic cholecystectomy were randomized to receive either a LTS-D (n=30) or LTS-II (n=30) for airway management. After induction of general anaesthesia the devices were inserted, their correct placement was verified and airway leak pressure was measured. Ease of insertion, quality of airway seal, fiberoptic view, risk of gastric insufflation, insertion of nasogastric tube and postoperative pharyngeal morbidity were examined.

RESULTS

First time and second time success rates were comparable for both groups (86% vs. 93% and 96% vs. 96% in LTS-D and LTS-II groups, respectively). One patient in each group could not be intubated after three attempts. After gas insufflation, ventilation of one patient in LTS-D and 2 patients in LTS-II groups was faulty and the patients were intubated with endotracheal tube. Time until delivery of first tidal volume for LTS-D and LTS-II was 20.8 +/- 11.6 s, and 18.2 +/- 4.8 seconds respectively (p = 0.27), fixation and manipulation time was 73.3 +/- 18.5 and 65.5 +/- 16.2 seconds, respectively (p = 0.096). Nasogastric tube insertion was successful in all patients. There were no significant differences in postoperative complaints.

CONCLUSIONS

Both devices provide a secure airway under conditions of elevated intra abdominal pressure.

Anaesthesia in prehospital emergencies and in the emergency room

AIMS

To review anaesthesia in prehospital emergencies and in the emergency room, and to discuss guidelines for anaesthesia indication; pre-oxygenation; anaesthesia induction and drugs; airway management; anaesthesia maintenance and monitoring; side effects and training.

METHODS

A literature search in the PubMed database was performed and 87 articles were included in this non-systematic review.

CONCLUSIONS

For pre-oxygenation, high-flow oxygen should be delivered with a tight-fitting face-mask provided with a reservoir. In haemodynamically unstable patients, ketamine may be the induction agent of choice. The rocuronium antagonist sugammadex may have the potential to make rocuronium a first-line neuromuscular blocking agent in emergency induction. An experienced health-care provider may consider prehospital anaesthesia induction. A moderately experienced health-care provider should optimise oxygenation, fasten hospital transfer and only try to intubate a patient in extremis. If intubation fails twice, ventilation should be resumed with an alternative supra-glottic airway or a bag-valve-mask device. A lesser experienced health-care provider should completely refrain from intubation, optimise oxygenation, fasten hospital transfer and only in extremis ventilate with an alternative supra-glottic airway or a bag-valve-mask device. With an expected difficult airway, the patient should be intubated awake. With an unexpected difficult airway, bag-valve-mask ventilation should be resumed and an alternative supra-glottic airway device inserted. Senior help should be called early. In a "can-not-ventilate, can-not-intubate" situation an alternative airway should be tried and if unsuccessful because of severe upper airway pathology, a surgical airway should be performed. Ventilation should be monitored continuously with capnography. Clinical training is important to increase airway management skills.

A critique of elective pediatric supraglottic airway devices

In 1988, when the Laryngeal Mask Airway-Classic (Intavent Orthofix, Maidenhead, UK), was introduced there were only two choices of airway management: tracheal tube or facemask. The supraglottic airway, as we now understand the term, did not exist. Yet, 20 years later, we are faced with an ever increasing choice of supraglottic airway devices (SAD). For many SADs, with the exception of the LMA-Classic and LMA-Proseal (Intavent Orthofix, Maidenhead, UK), there is a lack of high quality data of efficacy. The best evidence requires a randomized controlled trial comparing a new device against an established alternative, properly powered to detect clinically relevant differences in clinically important outcomes. Such studies in children are very rare. Safety data is even harder to establish particularly for rare events such as aspiration. Therefore, most safety data comes from extended use rather than high quality evidence which inevitably biases against newer devices. For reason of these factors, claims of efficacy and particularly safety must be interpreted cautiously. This narrative review aims to present the evidence surrounding the use of currently available pediatric SADs in routine anesthetic practice.

Oesophageal seal of the novel supralaryngeal airway device I-Gel in comparison with the laryngeal mask airways Classic and ProSeal using a cadaver model

BACKGROUND

Supraglottic airway devices are increasingly used in anaesthesia and emergency medicine. This study was designed to investigate the oesophageal seal of the novel supralaryngeal airway device, I-Gel (I-Gel), in comparison with two of the laryngeal mask airways, Classic (cLMA) and ProSeal (pLMA), in a model of elevated oesophageal pressure.

METHODS

The three supralaryngeal airway devices were inserted into eight unfixed cadaver models with exposed oesophagi that had been connected to a water column producing both a slow and a fast oesophageal pressure increase. The pressure applied until the loss of oesophageal seal during a slow and fast pressure increase was measured.

RESULTS

During the slow increase of pressure, the pLMA withstood an oesophageal pressure up to a median of 58 cm H(2)O, while the cLMA was able to block the oesophagus up to a median of 37 cm H(2)O, and I-Gel already lost its seal at 13 cm H(2)O. One minute after maximum pressure had been applied, the pLMA withstood an oesophageal pressure of 59 cm H(2)O, the cLMA of 46 cm H(2)O, and I-Gel airway of 21 cm H(2)O. A fast release of oesophageal fluid was accomplished through the oesophageal lumen of both the pLMA and I-Gel.

CONCLUSIONS

Both the pLMA and cLMA provided a better seal of the oesophagus than the novel I-Gel airway. The pLMA and I-Gel drain off gastrointestinal fluid fast through the oesophageal lumen. Thus, tracheal aspiration may be prevented with their use. Further study is necessary.

Influence of airway management strategy on "no-flow-time" during an "advanced life support course" for intensive care nurses - a single rescuer resuscitation manikin study

Background

In 1999, the laryngeal tube (VBM Medizintechnik, Sulz, Germany) was introduced as a new supraglottic airway. It was designed to allow either spontaneous breathing or controlled ventilation during anaesthesia; additionally it may serve as an alternative to endotracheal intubation, or bag-mask ventilation during resuscitation. Several variations of this supraglottic airway exist. In our study, we compared ventilation with the laryngeal tube suction for single use (LTS-D) and a bag-mask device. One of the main points of the revised ERC 2005 guidelines is a low no-flow-time (NFT). The NFT is defined as the time during which no chest compression occurs. Traditionally during the first few minutes of resuscitation NFT is very high. We evaluated the hypothesis that utilization of the LTS-D could reduce the NFT compared to bag-mask ventilation (BMV) during simulated cardiac arrest in a single rescuer manikin study.

Methods

Participants were studied during a one day advanced life support (ALS) course. Two scenarios of arrhythmias requiring defibrillation were simulated in a manikin. One scenario required subjects to establish the airway with a LTS-D; alternatively, the second scenario required them to use BMV. The scenario duration was 430 seconds for the LTS-D scenario, and 420 seconds for the BMV scenario, respectively. Experienced ICU nurses were recruited as study subjects. Participants were randomly assigned to one of the two groups first (LTS-D and BMV) to establish the airway. Endpoints were the total NFT during the scenario, the successful airway management using the respective device, and participants' preference of one of the two strategies for airway management.

Results

Utilization of the LTS-D reduced NFT significantly (p < 0.01). Adherence to the time frame of ERC guidelines was 96% in the LTS-D group versus 30% in the BMV group. Two participants in the LTS-D group required more than one attempt to establish the LTS-D correctly. Once established, ventilation was effective in 100%. In a subjective evaluation all participants preferred the LTS-D over BMV to provide ventilation in a cardiac arrest scenario.

Conclusion

In our manikin study, NFT was reduced significantly when using LTS-D compared to BMV. During cardiac arrest, the LTS-D might be a good alternative to BMV for providing and maintaining a patent airway. For personnel not experienced in endotracheal intubation it seems to be a safe airway device in a manikin use.

A comparison of seal in seven supraglottic airway devices using a cadaver model of elevated esophageal pressure

BACKGROUND

Supraglottic airway devices are increasingly important in clinical anesthesia and prehospital emergency medicine, but there are only few data to assess the risk for aspiration. We designed this study to compare the seal of seven supraglottic airway devices in a cadaver model of elevated esophageal pressure.

METHODS

The classic laryngeal mask airway, laryngeal mask airway ProSeal, intubating laryngeal mask airway Fastrach, laryngeal tube, laryngeal tube LTS II, Combitube, and Easytube were inserted into unfixed human cadavers with an exposed esophagus that had been connected to a water column of 130 cm height. Slow and fast increases of esophageal pressure were performed and the water pressure at which leakage appeared was registered.

RESULTS

The Combitube, Easytube, and intubating laryngeal mask Fastrach withstood the water pressure up to more than 120 cm H2O. The laryngeal mask airway ProSeal, laryngeal tube, and laryngeal tube LTS II were able to block the esophagus until 72-82 cm H2O. The classic laryngeal mask airway showed leakage at 48 cm H2O, but only minor leakage was found in the trachea. Devices with an additional esophageal drain tube drained fluid sufficiently without pulmonary aspiration.

CONCLUSIONS

Concerning the risk of aspiration, the use of devices with an additional esophageal drainage lumen might be superior for use in patients with an increased risk of aspiration. The Combitube, Easytube, and intubating laryngeal mask Fastrach showed the best capacity to withstand an increase of esophageal pressure.

Prospective randomized comparison of the new Laryngeal Tube Suction LTS II and the LMA-ProSeal for elective surgical interventions

BACKGROUND AND AIM

The Laryngeal Tube Suction (LTS) has recently undergone considerable changes in design. The new LTS II was compared with the LMA-ProSeal to determine device performance during general anaesthesia and controlled ventilation.

METHODS

After Institutional Review Board approval, 100 elective surgical patients were randomized to be ventilated with LTS II or LMA-ProSeal. The number of attempts (maximum of two, and then other device tested) and time until first tidal volume were recorded. Ventilation was standardized (tidal volume, 7 ml/kg; respiratory rate, 12 breaths/min) and the resulting end-tidal CO(2) was recorded. The airway leak pressure (maximum of 40 cmH(2)O) was measured at cuff pressures of 60 cmH(2)O. The ease of gastric tube insertion was evaluated. The devices were inspected for traces of blood after removal. Patients were questioned regarding post-operative complaints. The Mann-Whitney U-test was used to compare the groups.

RESULTS

The demographic data, American Society of Anesthesiologists' group, Mallampati score, and haemodynamic and respiratory variables were comparable for both groups of 50 patients. Insertion was successful in the first/second attempts in 44/4 patients for LTS II and in 43/6 patients for LMA-ProSeal. After two failed attempts, the other device was successfully used in one patient for LMA-ProSeal and in two patients for LTS II. The times until first tidal volume for LTS II and LMA-ProSeal were 25.0 +/- 10.1 and 25.5 +/- 11.5 s, respectively. The airway leak pressures were comparable: 33.1 (15-40) and 32.0 cmH(2)O (18-40 cmH(2)O) for LTS II and LMA-ProSeal, respectively. Gastric tube insertion failed in two patients in each group. Traces of blood were found in two patients with LTS II and in three patients with LMA-ProSeal. In both groups, post-operative complaints were mild and infrequent.

CONCLUSION

In this prospective randomized trial, LMA-ProSeal and LTS II were comparable in all respects.

Evaluation of the revised laryngeal tube suction: the laryngeal tube suction II in 100 patients

BACKGROUND

We prospectively assessed the performance of the laryngeal tube suction mark II (LTS II).

METHODS

LTS II was assessed during controlled and spontaneous ventilation during total i.v. anaesthesia. Ventilation adequacy, functional and anatomical positioning and airway seal were evaluated.

RESULTS

One hundred healthy patients (30F:70M) aged 18-85-yr-old were studied. Insertion of the LTS II was successful in 71 at first attempt, in 24 at second attempt and in five at third/fourth attempt. Median insertion time was 15 s (range 5-120 s). Temporary obstruction occurred in six patients. A median of one manipulation per patient was required to establish an airway (range 0-5). During maintenance, temporary airway obstruction occurred in eight patients. Use of the device was abandoned once during insertion, once during maintenance and once because of complications unrelated to the study. The airway was clear in 89 of 97 patients during maintenance and partially obstructed in eight. Median seal pressure was 29.5 (range 15-85) cm H2O. A gastric tube was passed via the posterior channel in 97 of 99 patients. The glottis was visible using a fibrescope passed via the device in 51% of patients. Via the drain tube the upper oesophagus was visible in 22% and this was open in 50%. Blood was visible on the device after removal in 12 patients. After the operation 14 patients reported mild sore throat.

DISCUSSION

The LTS II appears to be an improvement on its predecessor and merits further investigation comparing it with its competitors during use for anaesthesia and emergency airway management.

A comparison of the laryngeal tube-S and Proseal laryngeal mask during outpatient surgical procedures

BACKGROUND AND OBJECTIVE

The Laryngeal Tube Sonda (LTS) and the ProSeal Laryngeal Mask Airway (PLMA) are two new devices introduced for maintaining the airway during controlled ventilation under general anaesthesia. The present investigation compared their performance in a randomized controlled study.

METHODS

One hundred ASA I-II patients, aged 18-60 yr undergoing elective minor surgery, were randomized to receive either an LTS (n = 50) or PLMA (n = 50) for airway management. After induction of general anaesthesia, the devices were inserted, its correct placement was verified and airway leak pressure was measured. Ease of insertion, quality of airway seal, fibre-optic view and postoperative pharyngeal morbidity were examined.

RESULTS

There were no differences in patient characteristics for both groups. First-time and second-time success rates were comparable for both groups (86 vs. 88% and 96 vs. 98% in LTS and PLMA groups, respectively). The airway of one patient in each group could not be managed with these devices after three attempts. Time until delivery of first tidal volume for LTS and PLMA was 24.5 +/- 6.9 and 28.8 +/- 10.3 s. Fixation and manipulation time was 54.9 +/- 15.2 and 73.2 +/- 25 s, respectively (P < 0.05). Airway seal pressure (cm H(2)O) for LTS and PLMA was 20 +/- 8.6 and 24.1 +/- 10.8, respectively (P = 0.04). Patients were questioned on a variety of postoperative pharyngeal morbidities. Only hoarseness was more frequent in the LTS group.

CONCLUSIONS

Both devices provide a secure airway, are similar in clinical utility and are easy to insert. Better airway seal was detected in the PLMA group.

Comparison of LMA Unique, Ambu laryngeal mask and Soft Seal laryngeal mask during routine surgical procedures

BACKGROUND AND OBJECTIVE

This study was performed to compare three disposable airway devices, the LMA Unique (LMA-U), the Ambu laryngeal mask (Ambu LM) and the Soft Seal laryngeal mask (Soft Seal LM) for elective general anaesthesia during controlled ventilation in non-paralysed patients.

METHODS

One hundred and twenty ASA I-III patients scheduled for routine minor obstetric surgery were randomly allocated to the LMA-U (n = 40), Ambu LM (n = 40) or Soft Seal LM (n = 40) groups, respectively. Patients were comparable with respect to weight and airway characteristics. A size 4 LMA was used in all patients and inserted by a single experienced anaesthesiologist. Oxygenation, overall success rate, insertion time, cuff pressure and resulting airway leak pressure were determined as well as a subjective assessment of handling and the incidence of sore throat, dysphagia and hoarseness.

RESULTS

Time of insertion was shortest with the Ambu LM, while failure rates were comparable with the LMA-U, the Ambu LM and the Soft Seal LM (median 19 s; range 8-57 s; success rate 100% vs. 14; 8-35; 97% vs. 20; 12-46; 95%). Insertion was judged 'excellent' in 75% of patients in the LMA-U group, in 70% of patients in Ambu LM group and in 65% of patients in the Soft Seal LM group. There was no difference between devices with respect to postoperative airway morbidity at 6 h or 24 h following surgery.

CONCLUSIONS

All three disposable devices were clinically suitable with respect to insertion times, success rates, oxygenation, airway and leak pressures, as well as to subjective handling and postoperative airway morbidity.

New airways for resuscitation?

Over the last 15 years supraglottic airway devices (SADs), most notably the classic laryngeal mask airway (LMA) have revolutionised airway management in anaesthesia. In contrast for resuscitation, both in and outside hospital, facemask ventilation and tracheal intubation remain the mainstays of airway management. However there is evidence that both these techniques have complications and are often poorly performed by inexperienced personnel. Tracheal intubation also has the potential to cause serious harm or death through unrecognised oesophageal intubation. SADs may have a role in airway management for resuscitation as first responder devices, rescue devices or for use during patient extraction. In particular they may be beneficial as the level of skill required to use the device safely may be less than for the tracheal tube. Concerns have been expressed over the ability to ventilate the lungs successfully and also the risk of aspiration with SADs. The only SADs recommended by ILCOR in its current guidance are the classic LMA and combitube. Several SADs have recently been introduced with claims that ventilation and airway protection is improved. This pragmatic review examines recent developments in SAD technology and the relevance of this to the potential for using SADs during resuscitation. In addition to examining research directly related to resuscitation both on bench models and in patients the review also examines evidence from anaesthetic practice. SADS discussed include the classic, intubating and Proseal LMAs, the combitube, the laryngeal tube, laryngeal tube sonda mark I and II and single use laryngeal masks.

Supraglottic airway devices

Supraglottic airway devices are developed with increasing frequency following the overwhelming success of the laryngeal mask airway (LMA). Currently, the LMA, the ProSeal laryngeal mask airway (PLMA), the laryngeal tube (LT), the laryngeal tube with integrated suctioning tube (LTS) and the oesophageal tracheal combitube (OTC) are the best evaluated and most widespread devices. Both the LMA and the PLMA have been shown to be perfectly suitable for routine anaesthesia and emergency airway management. While the LMA is limited by the lack of reliable protection against aspiration, the value of the PLMA in this respect remains undetermined yet. LT and LTS are primarily intended as emergency airway devices, but have also been successfully used during controlled ventilation in adults. The OTC, though advocated for emergency as well as routine use, is limited by high airway morbidity and possible serious complications.