The Laryngeal Mask Airway (LMA) is a frequently-used efficient airway device, yet it sometimes seals poorly, thus reducing the efficacy of positive-pressure ventilation. The Perilaryngeal Airway (CobraPLA) is a novel airway device with a larger pharyngeal cuff (when inflated). We tested the hypothesis that the CobraPLA was superior to LMA with regard to insertion time and airway sealing pressure and comparable to LMA in airway adequacy and recovery characteristics. After midazolam and fentanyl, 81 ASA I-II outpatients having elective surgery were randomized to receive an LMA or CobraPLA. Anesthesia was induced with propofol (2.5 mg/kg, IV), and the airway inserted. We measured 1) insertion time; 2) adequacy of the airway (no leak at 15-cm-H2O peak pressure or tidal volume of 5 ml/kg); 3) airway sealing pressure; 4) number of repositioning attempts; and 5) sealing quality (no leak at tidal volume of 8 ml/kg). At the end of surgery, gastric insufflation, postoperative sore throat, dysphonia, and dysphagia were evaluated. Data were compared with unpaired t-tests, chi-square tests, or Fisher’s Exact tests; P<0.05 was significant. Patient characteristics, insertion times, airway adequacy, number of repositioning attempts, and recovery were similar in each group. Airway sealing pressure was significantly greater with CobraPLA (23±6 cm H2O) than LMA (18±5 cm H2O, P<0.001). The CobraPLA has insertion characteristics similar to LMA, but better airway sealing capabilities.
Airway: Sealing. Cuff Pressure. Insertion. Leak. Pharynx; Equipment: Laryngeal mask airway. Perilaryngeal airway; Ventilation: Controlled. Spontaneous; Anesthesia
To compare two different supraglottic airway devices, the laryngeal mask airway (LMA) and the I-gel, regarding easiness of insertion of the device, leak pressure, gastric insufflation, end tidal CO2, oxygen saturation, hemodynamic and postoperative complications in anesthetized, spontaneously ventilated adult patients performing different non-emergency surgical procedures.
Materials and Methods:
The study was carried out as a prospective, randomized, clinical trial among 80 patients who underwent different surgical procedures under general anesthesia with spontaneous ventilation in supine position. They were equally randomized into two groups: I-gel and LMA groups. Both the devices were compared with regard to heart rate, arterial BP, SPO2, end-tidal CO2, number and duration of insertion attempts, incidence of gastric insufflation, leak pressure and airway assessment after removal of the device.
No statistically significant difference was reported between both the groups, regarding heart rate, arterial BP, SPO2 and end-tidal CO2. The mean duration of insertion attempts was 15.6±4.9 seconds in the I-gel group, while it was 26.2±17.7 seconds in the LMA group. The difference between both the groups regarding duration of insertion attempts was statistically significant (P=0.0023*), while the number of insertion attempts was statistically insignificant between both the study groups (P>0.05). Leak pressure was (25.6±4.9 vs. 21.2±7.7 cm H2O) significantly higher among studied patients of the I-gel group (P=0.016*) and the incidence of gastric insufflation was significantly more with LMA group 9 (22.5%) vs. I-gel group (5%) (P=0.016).
Both LMA and I-gel do not cause any significant alteration in the hemodynamic status of the patients, end tidal CO2, and SPO2. The postoperative complications were not significantly different except nusea and vomiting was statistically significant higher in LMA group (P=0.032). among both LMA and I-gel patients. Insertion of I-gel was significantly easier and more rapid than insertion of LMA. Leak pressure was significantly higher with I-gel than LMA and thus incidence of gastric insufflation was significantly lower with I-gel.
Classical laryngeal mask airway; I-gel; supraglottic airway devices
The laryngeal mask airway (LMA) is a supraglottic airway management device. The LMA is preferred for airway management in paediatric patients for short duration surgical procedures. The recently introduced ProSeal (PLMA), a modification of Classic LMA, has a gastric drainage tube placed lateral to main airway tube which allows the regurgitated gastric contents to bypass the glottis and prevents the pulmonary aspiration. This study was done to compare the efficacy of ProSeal LMA with an endotracheal tube in paediatric patients with respect to number of attempts for placement of devices, haemodynamic responses and perioperative respiratory complications. Sixty children, ASA I and II, weighing 10-20 kg between 2 and 8 years of age group of either sex undergoing elective ophthalmological and lower abdominal surgeries of 30-60 min duration, randomly divided into two groups of 30 patients each were studied. The number of attempts for endotracheal intubation was less than the placement of PLMA. Haemodynamic responses were significantly higher (P<0.05) after endotracheal intubation as compared to the placement of PLMA. There were no significant differences in mean SpO2 (%) and EtCO2 levels recorded at different time intervals between the two groups. The incidence of post-operative respiratory complications cough and bronchospasm was higher after extubation than after removal of PLMA. The incidence of soft tissue trauma was noted to be higher for PLMA after its removal. There were no incidences of aspiration and hoarseness/sore throat in either group. It is concluded that ProSeal LMA can be safely considered as a suitable and effective alternative to endotracheal intubation in paediatric patients for short duration surgical procedures.
ET tube; haemodynamic response; PLMA
Supraglottic airway devices play an important role in ophthalmic surgery. The flexible laryngeal mask airway (LMA™) is generally the preferred airway device. However, there are no studies comparing it with the Cobra perilaryngeal airway (CobraPLA™) in pediatric ophthalmic procedures.
To analyze the intraoperative device stability and ability to maintain normocarbia of CobraPLA™ and compare it to that with flexible LMA™.
Materials and Methods:
Ninety children of American Society for Anesthesiologists physical status 1 and 2, aged 3–15 years scheduled for elective ophthalmic surgeries were randomly assigned to either the CobraPLA™ or the flexible LMA™ group. After placement of each airway device, oropharyngeal leak pressure (OLP) was noted. Adequate seal of the devices was confirmed at an inspired pressure of 15 cm H2O and pressure-controlled ventilation was initiated. Device displacement was diagnosed if there was a change in capnograph waveform, audible or palpable gas leak, change in expired tidal volume to <8 ml/kg, end-tidal carbon-dioxide persistently >6 kPa, or need to increase inspired pressure to >18 cm H2O to maintain normocarbia.
Demographic data, duration, and type of surgery in both the groups were similar. A higher incidence of intraoperative device displacement was noted with the CobraPLA™ in comparison to flexible LMA™ (P < 0.001). Incidence of displacement was higher in strabismus surgery (7/12). Insertion characteristics and ventilation parameters were comparable. The OLP was significantly higher in CobraPLA™ group (28 ± 6.8 cm H2O) compared to the flexible LMA™ group (19.9 ± 4.5 cm H2O) (P < 0.001). Higher surgeon dissatisfaction (65.9%) was seen in the CobraPLA™ group.
The high incidence of device displacement and surgeon dissatisfaction make CobraPLA™ a less favorable option than flexible LMA™ in ophthalmic surgery.
Airway complication; CobraPLA™; flexible laryngeal mask airway; pediatric ophthalmic surgery
The objective of the study was to compare the performance of i-gel supraglottic airway with cLMA in difficult airway management in post burn neck contracture patients and assess the feasibility of i-gel use for emergency airway management in difficult airway situation with reduced neck movement and limited mouth opening.
Prospective, crossover, randomized controlled trial was performed amongst forty eight post burn neck contracture patients with limited mouth opening and neck movement. i-gel and cLMA were placed in random order in each patient. Primary outcome was overall success rate. Other measurements were time to successful ventilation, airway leak pressure, fiberoptic glottic view, visualization of square wave pattern.
Success rate for the i-gel was 91.7% versus 79.2% for the cLMA. i-gel required shorter insertion time (19.3 seconds vs. 23.5 seconds, P=0.000). Airway leak pressure difference was statistically significant (i-gel 21.2 cm H20; cLMA 16.9 cm H20; P=0.00). Fiberoptic view through the i-gel showed there were less epiglottic downfolding and better fiberoptic view of the glottis than cLMA. Overall agreement in insertion outcome for i-gel was 22/24 (91.7%) successes and 2/24(8.3%) failure and for cLMA, 19/24 (79.16%) successes and 5/24 (16.7%) failure in the first attempt.
The i-gel is cheap, effective airway device which is easier to insert and has better clinical performance in the difficult airway management of the airway in the post burn contracture of the neck. Our study shows that i-gel is feasible for emergency airway management in difficult airway situation with reduced neck movement and limited mouth opening in post burn neck.
cLMA; difficult airway management; i-gel; post burn neck contracture
Second generation extraglottic airway devices with gastric access and separate breathing channels have ushered in a new era where their use is increasingly prevalent in surgical patients who would have been traditionally intubated for general anesthesia. New innovations like the i-gel, which is constructed of a thermoplastic elastomer, provide an airtight seal around patient's perilaryngeal anatomy without the inflatable cuff mechanism found in the laryngeal mask airway supreme (LMAS).
We conducted a randomized controlled trial comparing the LMAS with the i-gel in 70 anesthetized paralyzed patients undergoing laparoscopic female sterilization. Our primary outcome measure was the oropharyngeal leak pressure (OLP). We studied secondary outcomes of successful first attempt insertion rates, time and ease of the airway and gastric tube insertion, leak fractions and pharyngeal morbidity.
We found no difference in the OLP between LMAS and i-gel, 25.9 (4.2) versus 24.4 (4.3) s, P=0.153. Both devices had similar first attempt insertion rates (LMAS 94% vs. i-gel 91%) with similar ease and comparable times to achieve an effective airway, LMAS 14.7 (2.7) versus i-gel 16.5 (9.6) s, P=0.306, although gastric tube insertion was easier and faster for the LMAS, 7.9 (1.9) versus i-gel 14.8 (7.7) s, P<0.005. Intraoperatively, there was a significantly greater leak fraction with the i-gel of 0.06 (0.03) versus 0.04 (0.02) with the LMAS, P=0.013. Three patients (8.6%) with LMAS had mild sore throat; one patient (2.9%) had mucosal injury. No complications were documented in the i-gel group.
Both these extraglottic airway devices offer similar OLPs, high insertion success rates at the first attempt with similar ease and insertion times (albeit longer gastric tube insertion with i-gel). Both provided effective ventilation despite a higher leak fraction with i-gel that was clinically inconsequential.
Extraglottic airway devices; i-gel; laparoscopic surgery; laryngeal mask airway supreme; leak fraction; leak pressures
The aim of this study was to evaluate intraocular pressure (IOP) and hemodynamic responses following insertion of laryngeal mask airway (LMA) or endotracheal tube (ETT) after anesthesia induction with propofol and remifentanil in cataract surgery.
Materials and Methods:
In a randomized controlled study, 50 adults scheduled for elective cataract extraction procedure under general anesthesia were allocated to LMA insertion (n = 25) or ETT (n = 25) groups. IOP, systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were measured after insertion of the airway device every minute up to 5 min.
There were no significant differences between LMA and ETT groups in SBP, DBP, HR, and IOP immediately after airway instrumentation up to 5 min, except in 4th min in DBP, 2nd min in HR, and 5th min in IOP (7.9 ± 2.3 mmHg in LMA and 9.4 ± 2.5 mmHg in ETT group; P = 0.030). There was good surgeon satisfaction for providing acceptable surgical field in both groups (88% in LMA and 80% in ETT group; P = 0.702).
Propofol combined with remifentanil provides good and excellent conditions for insertion of LMA or ETT with minimal hemodynamic disturbances in cataract surgery. Considering LMA insertion is less traumatic than ETT, using LMA may be better than ETT for airway securing in these patients.
Cataract surgery; hemodynamic responses; laryngeal mask airway; propofol; remifentanil
The conventional sequence when using supraglottic airway devices is insertion, cuff inflation and fixation. Our hypothesis was that a tighter fit of the cuff and tip could be achieved with a consequently lower incidence of air leak, better separation of gastrointestinal and respiratory tracts and less airway morbidity if the device were first affixed and the cuff then inflated.
Our clinical review board approved the study (public registry number DRKS00003174). An LMA Supreme® was inserted into 184 patients undergoing lower limb arthroscopy in propofol-remifentanil anaesthesia who were randomly assigned to either the control (inflation then fixation; n = 92) or study group (fixation then inflation; n = 92). The cuff was inflated to 60 cmH2O. The patients’ lungs were ventilated in pressure-controlled mode with 5 cmH2O PEEP, Pmax to give 6 ml kg-1 tidal volume, and respiratory rate adjusted to end-tidal CO2 of 4.8 and 5.6 kPa. Correct cuff and tip position were determined by leak detection, capnometry trace, oropharyngeal leak pressure, suprasternal notch test, and lube-tube test. Bowl and cuff position and the presence of glottic narrowing were assessed by fiberscopic examination. Postoperative dysphagia, hoarseness and sore throat were assessed with a questionnaire. Ventilatory impairment was defined as a tidal volume < 6 ml kg-1 with Pmax at oropharyngeal leak pressure, glottic narrowing was defined as an angle between the vocal cords under 16 degrees.
The incidence of incorrect device position (18% vs. 21%), failed ventilation (10% vs. 9%), leak pressure (24.8 vs. 25.2 cmH2O, p = 0.63), failed lube-tube test (16.3% vs. 17.6%) and glottic narrowing (19.3% vs. 14.1%, p = 0.35) was similar in both groups (control vs. study, resp.). When glottic narrowing occurred, it was more frequently associated with ventilatory impairment in the control group (77% vs. 39%; p = 0.04). Airway morbidity was more common in the control group (33% vs. 19%; p < 0.05).
Altering the sequence of cuff inflation and device fixation does not affect device position, oropharyngeal leak pressures or separation of gastrointestinal and respiratory tracts. It reduces the incidence of glottic narrowing with impaired ventilation and also perioperative airway morbidity.
Supraglottic airway; Insertion sequence; Malposition; Endoscopic evaluation; Glottic narrowing; Ventilatory impairment; Airway morbidity
The laryngeal mask airway (LMA) is a supraglottic airway device designed to seal around the laryngeal inlet. A controlled study was designed to compare the effectiveness and complications in inserting the LMA when the cuff is fully deflated and partially inflated.
Materials and Methods
American Society of Anesthesiologists physical status I or II 172 female patients scheduled for gynecologic procedures were included in this study. Patients were randomly allocated into one of the two groups; fully deflated (n=86) and partially inflated group (n=86). A size #4 LMA was inserted. The number of attempts, time taken for successful insertion, grade of leak, grade of fiberoptic view, and complications were evaluated.
All 172 patients completed the study protocol. The number of attempts, time taken for successful insertion, and grade of leak were not significantly different between the two groups. The grade of fiberoptic view and complications were lower in the fully deflated group.
The fully deflated method is more accurate and safe because of better fiberoptic view and lesser complications than the partially inflated group.
Complication; laryngeal mask airway
Perfusion index (PI) is a non-invasive numerical value of peripheral perfusion obtained from a pulse oximeter. In this study, we evaluated the efficacy of PI for detecting haemodynamic stress responses to insertion of i-gel, laryngeal mask airway (LMA) and endotracheal tube and compare, its reliability with the conventional haemodynamic criteria in adults during general anaesthesia.
Sixty patients scheduled for elective general surgery under general anaesthesia were randomised to three groups. (i-gel, LMA and ET groups (n=20/group). Heart rate (HR) (positive if ≥10 bpm), systolic blood pressure (SBP), diastolic blood pressure (DBP) (positive if ≥15 mm Hg) and PI (positive if ≤10%) were monitored for 5 min after insertion. Main outcome measures: SBP, DBP, HR and PI were measured before induction of anaesthesia and before and after insertion of the airway device.
Insertion of airway devices produced significant increases in HR, SBP and DBP in LMA and ET groups. Moreover, PI was decreased significantly by 40%, 100% and 100% in the three groups. Using the PI criterion, the sensitivity was 100% (CI 82.4-100.0%). Regarding the SBP and DBP criterions, the sensitivity was 44.4% (CI 24.6-66.3%), 55.6% (CI 33.7-75.4%) respectively. Also, significant change in the mean PI over time (from pre-insertion value to the 1st min, 3rd min, until the 4th min after insertion without regard the device type), (P<0.001).
PI is a reliable and easier alternative to conventional haemodynamic criteria for detection of stress response to insertion of i-gel, LMA and ET during propofol fentanyl isoflurane anaesthesia in adult patients.
Airway management; classic laryngeal mask airway; endotracheal tube; equipment design; i-gel; intubation; laryngeal masks; perfusion index; stress response
Though fiberoptic intubation (FOI) is considered the gold standard for securing a difficult airway in a child, it may be technically difficult in an anesthetized child. The hypothesis for this study was that it would be easier to perform FOI via a laryngeal mask airway (LMA) than a modified oropharyngeal airway with the advantage of maintaining anesthesia and oxygenation during the process.
Materials and Methods:
30 children aged 6 months to 5 years undergoing elective surgery under general anesthesia were randomized to two groups to have fiberoptic bronchoscope (FOB) guided intubation either via a modified Guedel airway (FOB-ORAL) or a classic LMA (FOB-LMA). In the FOB-LMA group, the LMA was removed when a second smaller endotracheal tube was anchored to the proximal end of the tracheal tube in place.
Oral fiberoptic intubation was successful in all children. The first attempt success rate was 11/15 (73.33%) in the FOB-LMA group and 3/15 (20%) in the FOB-ORAL group (P = 0.012). Subsequent attempts at intubation were successful after 90° anticlockwise rotation of the endotracheal tube over the FOB. The time taken for fiberoptic bronchoscopy was significantly less in FOB-LMA group (59.20 ± 42.85 sec vs 108.66 ± 52.43 sec). The incidence of desaturation was higher in the FOB-ORAL group (6/15 vs 0/15).
In children, fiberoptic bronchoscopy and intubation via an LMA has the advantage of being easier, with shorter intubation time and continuous oxygenation and ventilation throughout the procedure. Removal of the LMA following intubation requires particular care.
Difficult; equipment; fiberoptic bronchoscope; intubation; laryngeal mask airway; modified oropharyngeal Guedel airway; tracheal
The relatively recently developed I-gel (Intersurgical Ltd., Workingham, England) is a supraglottic airway device designed for single-use that, unlike conventional LMAs, does not require an inflatable cuff. In addition, the I-gel, much like the Proseal LMA (PLMA), has a gastric drainage tube associated with an upper tube for decompression of the stomach, thereby avoiding acid reflux and decreasing the risk of pulmonary absorption. The purpose of this study was to compare PLMA and I-gel devices in patients undergoing gynecological laparoscopy based on sealing pressure before and during pneumoperitoneum, insertion time, and gas exchange.
Following Institutional Review Board approval and written informed consent, 30 adult patients were randomly allocated to one of two groups (the PLMA or I-gel group). In each case, insertion time and number of attempts were recorded. After successful insertion, airway leak pressure was measured.
Successful insertion and mechanical ventilation with both supraglottic airway devices was achieved on the first attempt in all 30 patients, and there were no significant differences with respect to insertion time. Likewise, leak pressure did not vary significantly either between or within groups after CO2 insufflation. In addition, differences between leak volume and leak fraction between groups were not significant.
The results of our study indicate that the I-gel is a reasonable alternative to the PLMA for controlled ventilation during laparoscopic gynecologic surgery.
We evaluated the efficacy of an alternative technique, for insertion of the silicone laryngeal mask airway (LMA) Classic™ in 40 American Society of Anesthesiologists grade ASA I and II patients scheduled for elective surgery. In group I (Index Finger group), the LMA was inserted by the classic index finger technique and, in group T (Thumb Insertion group), the thumb insertion technique was used. Ease of insertion, fiberoptic laryngoscopic position, cuff pressures and laryngopharyngeal morbidity were assessed in both study groups. On statistical analysis, both groups were comparable in all respects. From our study it can be concluded that thumb insertion is an effective insertion technique for the LMA Classic™.
Laryngeal mask airway (LMA) is increasingly being used in children as it is less invasive compared to endotracheal intubation and causes less discomfort in the postoperative period. However, some concerns remained about its safety during positive pressure ventilation in children.
In a prospective randomized trial, 100 ASA I and II children weighing between 10-20 kg in the range of 2-10 years of age, scheduled for elective surgery were randomly allocated to one of the two groups of 50 patients each. The efficacy of LMA in children during positive pressure ventilation, its haemodynamic changes and postoperative complications were compared to endotracheal intubation. Insertion of LMA was easier in 94% patients while endotracheal intubation was done easily in 53% of patients only (p<0.05). The changes in haemodynamic parameters were significantly higher after endotracheal intubation as compared to LMA placement. Furthermore these changes persisted for longer duration after endotracheal intubation in comparison to LMA insertion (5 min vs 3 min). Incidence of postoperative complications i.e. bronchospasm, laryngospasm and soft tissue trauma was significantly higher (p<0.05) after endotracheal intubation as compared to LMA insertion.
To conclude, the laryngeal mask airway is a suitable alternative to endotracheal intubation for positive pressure ventilation in children.
Laryngeal mask airway; Endotracheal intubation; Children
Bystander resuscitation plays an important role in lifesaving cardiopulmonary resuscitation (CPR). A significant reduction in the "no-flow-time", quantitatively better chest compressions and an improved quality of ventilation can be demonstrated during CPR using supraglottic airway devices (SADs). Previous studies have demonstrated the ability of inexperienced persons to operate SADs after brief instruction. The aim of this pilot study was to determine whether an instruction manual consisting of four diagrams enables laypersons to operate a Laryngeal Mask Supreme® (LMAS) in the manikin.
An instruction manual of four illustrations with speech bubbles displaying the correct use of the LMAS was designed. Laypersons were handed a bag containing a LMAS, a bag mask valve device (BMV), a syringe prefilled with air and the instruction sheet, and were asked to perform and ventilate the manikin as displayed. Time to ventilation was recorded and degree of success evaluated.
A total of 150 laypersons took part. Overall 145 participants (96.7%) inserted the LMAS in the manikin in the right direction. The device was inserted inverted or twisted in 13 (8.7%) attempts. Eight (5.3%) individuals recognized this and corrected the position. Within the first 2 minutes 119 (79.3%) applicants were able to insert the LMAS and provide tidal volumes greater than 150 ml (estimated dead space). Time to insertion and first ventilation was 83.2 ± 29 s. No significant difference related to previous BLS training (P = 0.85), technical education (P = 0.07) or gender could be demonstrated (P = 0.25).
In manikin laypersons could insert LMAS in the correct direction after onsite instruction by a simple manual with a high success rate. This indicates some basic procedural understanding and intellectual transfer in principle. Operating errors (n = 91) were frequently not recognized and corrected (n = 77). Improvements in labeling and the quality of instructional photographs may reduce individual error and may optimize understanding.
Objective: To compare the postoperative complications between Laryngeal Mask Airway (LMA) and endotracheal tube (ETT) during low-flow anesthesia with controlled ventilation.
Methodology: Eighty adult Patients with ASA class I or II were randomly allocated into two forty-patient groups (ETT or LMA). Cuff pressure was monitored during anesthesia. After high uptake period, fresh gas flow (FGF) was decreased to 1 lit/min and isoflurane set to 1%. Monitoring during anesthesia included non-invasive blood pressure, ECG, ETCO2 and pulse oximetry. System leakage (>100 ml/min), rebreathing and any attempt to increase FGF to overcome the leak were monitored during anesthesia. Later, patients were extubated and transferred to Post Anesthesia Care Unit (PACU). In PACU, the incidence of sore throat, cough, difficulty in swallowing and shivering was monitored for all patients.
Results: Leakage was observed in two and three cases in ETT and LMA groups respectively (P>0.05). Postoperative cough, sore throat and difficulty in swallowing were significantly less in LMA than ETT group. No significant difference was observed regarding ETCo2 values between 2 groups.
Conclusion: If careful measures regarding insertion techniques, correct LMA position and routine monitoring of LMA cuff pressure are taken, LMA can be used as a safe alternative with lower incidence of post operation complication compared with ETT during low-flow controlled anesthesia with modern anesthetic machines.
Laryngeal Mask Aiway; Endotracheal Tube; Low-flow anesthesia; Complications; Controlled ventilation
We performed a prospective, open-label, randomised controlled trial comparing the air-Q® against the LMA-ProSeal™ in adults undergoing general anaesthesia. One hundred subjects (American Society of Anesthesiologists physical status 1–3) presenting for elective, outpatient surgery were randomly assigned to 52 air-Q® and 48 ProSeal devices. The primary study endpoint was airway seal pressure. Oropharyngolaryngeal morbidity was assessed secondarily. Mean (SD) airway seal pressures for the air-Q® and ProSeal were 30 (7) cmH2O and 30 (6) cmH2O, respectively (p = 0.47). Postoperative sore throat was more common with the air-Q® (46% vs 38%, p = 0.03) as was pain on swallowing (30% vs 5%, p = 0.01). In conclusion, the air-Q® performs well as a primary airway during the maintenance of general anaesthesia with an airway seal pressure similar to that of the ProSeal, but with a higher incidence of postoperative oropharyngolaryngeal complaints.
Submental endotracheal intubation is a simple and secure alternative to either nasoendotracheal intubation or a tracheostomy in the airway management of maxillofacial trauma. However, a submental endotracheal intubation is quite difficult to manage if adverse events such as a tube obstruction, accidental extubation, or a leaking cuff with the endotracheal tube in the submental route occur, which could endanger the patient. This paper describes the use of a LMA-Fastrach™ETT in the submental endotracheal intubation of patients suffering from maxillofacial trauma. One of the patients was a 16-year-old male, and the other was a 19-year-old male. They were scheduled for an open reduction and internal fixation of the maxillofacial fracture including naso-orbital-ethmoidal (NOE) complex, and a zygomaticomaxillary complex fracture. A submental intubation with a LMA-Fastrach™ETT was performed in both cases, and the operation proceeded without any difficulties. These cases show that the use of the LMA-Fastrach™ETT can improve the safety and efficacy of submental endotracheal intubation. This is because the LMA-Fastrach™ETT has a freely detachable connector, and is flexible enough to keep the patency despite the acute angle of airway.
LMA-Fastrach™ETT; maxillofacial trauma; submental intubation
Helicopters and light (unpressurised) aircraft are used increasingly for the transport of ventilated patients. Most of these patients are ventilated through endotracheal tubes (ETTs), others through laryngeal mask airways (LMAs). The cuffs of both ETTs and LMAs inflate with increases in altitude as barometric pressure decreases (30 mbar/1000 feet).
Tracheal mucosa perfusion becomes compromised at a pressure of approximately 30 cm H2O; critical perfusion pressure is 50 cm H2O.
The change in dimensions of the inflated cuffs of a size 8 ETT and a size 5 LMA were measured with digital callipers at 1000 feet intervals in the unpressurised cabin of an Agusta 109 helicopter used by the Warwickshire and Northamptonshire Air Ambulance.
A linear expansion in cuff dimensions as a function of altitude increase was identified. For ETTs, a formula for removal of air from the cuff with increasing altitude was calculated and is recommended for use in aeromedical transfers. This is 1/17×1.1 = 0.06 ml/1000 foot ascent/ml initial cuff inflation.
The data for LMA cuff expansion failed to show significant correlation with altitude change. Further work is required to determine a similar rule of thumb for LMA cuff deflation.
We compared the usefulness of the laryngeal tube (LT) with the intubating laryngeal mask airway (ILMA) in 51 patients whose necks were stabilised by manual in-line traction. After induction of anaesthesia and neuromuscular block, the LT and ILMA were inserted consecutively in a randomised, crossover design. During pressure-controlled ventilation (20 cmH2O inspiratory pressure), we measured insertion attempts, time to establish positive-pressure ventilation, tidal volume, gastric insufflation, and minimum airway pressure at which gas leaked around the cuff. Data were compared using Wilcoxon signed-rank tests; P<0.05 was considered significant. Insertion was more difficult with the LT (successful at first attempt in 16 patients) than with the ILMA (successful at first attempt in 42 patients, P<0.0001). Time required for insertion was longer for the LT (28 [23–35] sec, median [interquartile range]) than the ILMA (20 [15–25] sec, P=0.0009). Tidal volume was less for the LT (440 [290–670] ml) than the ILMA. (630 [440–750] ml, P=0.013). Minimum airway pressure at which gas leak occurred and incidence of gastric insufflation were similar with two devices. In patients whose necks were stabilised with manual in-line traction, insertion of the ILMA was easier and quicker than insertion of the LT and tidal volume was greater with the ILMA than the LT.
Anaesthesia; equipment; airway; intubating laryngeal mask airway; laryngeal tube; cervical spine immobilization
Laryngeal mask airways (LMAs) are often used as airway rescue devices where laryngoscopy is difficult. The LMA does not protect the airway and is preferably replaced with a cuffed endotracheal tube. There are reports of cases where an Eschmann tracheal tube introducer (ETTI) was successfully used to bridge between a standard LMA and an endotracheal tube. This project was designed to determine whether an Eschmann stylet can reliably be passed through an LMA into the trachea as a means of rescue intubation.
Nineteen emergency medicine residents and attending physicians, who were participants in a cadaveric airway course, placed and inflated a size 4 LMA (The Laryngeal Mask Company Ltd., San Diego, CA) on each of six unembalmed human cadavers in the usual fashion. They then attempted to pass a lubricated, 15 Fr, reusable, coude-tipped ETTI (Portex, Smiths Medical, Keene, NH)) through the airspace/handle of the inflated LMA. The LMA was then deflated and removed while the ETTI was held in place. Investigators then determined the location of the ETTI by laryngoscopy.
Of 114 attempts at the rescue procedure, 59 resulted in placement of the bougie into the trachea, yielding an overall success rate of 52% (95% CI 48%–56%). There were no significant differences in performance based on level of training of residents or years of experience of attending physicians.
While not a primary difficult airway option, the use of a ETTI as a bridge device between LMA and endotracheal tube was successful about 50% of the time.
Low flow anesthesia can lead to reduction of anesthetic gas and vapor consumption. Laryngeal mask airway (LMA) has proved to be an effective and safe airway device. The aim of this study is to assess the feasibility of laryngeal mask airway during controlled ventilation using low fresh gas flow (1.0 L/min) as compared to endotracheal tube (ETT).
Patients and Methods
Fifty nine non-smoking adult patients; ASA I or II, being scheduled for elective surgical procedures, with an expected duration of anesthesia 60 minutes or more, were randomly allocated into two groups - Group I (29 patients) had been ventilated using LMA size 4 for females and 5 for males respectively; and Group II (30 patients) were intubated using ETT. After 10 minutes of high fresh gas flow, the flow was reduced to 1 L/min. Patients were monitored for airway leakage, end-tidal CO2(ETCO2), inspiratory and expiratory isoflurane and nitrous oxide fraction concentrations, and postoperative airway-related complications.
Two patients in the LMA-group developed initial airway leakage (6.9%) versus no patient in ETT-group. Cough and sore throat were significantly higher in ETT patients. There were no evidences of differences between both groups regarding ETCO2, uptake of gases, nor difficulty in swallowing.
The laryngeal mask airway proved to be effective and safe in establishing an airtight seal during controlled ventilation under low fresh gas flow of 1 L/min, inducing less coughing and sore throat during the immediate postoperative period than did the ETT, with continuous measurement and readjustment of the tube cuff pressure.
Endotracheal intubation; laryngeal mask airway; low flow anesthesia
Background and objectives
This study aims to compare the frequency of ideal anatomic placement of the Laryngeal Mask Airway (LMA) using the traditional blind insertion approach with one where placement was facilitated by the use of a laryngoscope. Laryngeal Mask Airway is a supraglottic device in providing general anaesthesia.
A prospective comparison of 60 patients divided into 2 groups (30 with the blind technique and 30 with the direct technique) were evaluated with 2 airway assessment methods, Wilson and Mallampati. We also considered whether there was a relationship between these criteria and the successful placement into an ideal position. Other variables were considered, including hemodynamics. Five placement visual ordinals were used to grade the LMA position.
There was no statistically significant difference between group 1 and group 2 (P=0.279) in terms of Campbell category. There was no statistically significant relation between Wilson airway score or Mallampati class and Campbell category (p=0.633 and 0.239 respectively). There was no statistically significant difference in systolic and diastolic BP at 1, 2 and 5 min post insertion between the two groups, but there was a statistically significant difference in 1 and 2 minute post insertion pulse rate (P=0.004).
Blind insertion technique is easier and simpler method for insertion of LMA and has a reasonable success during insertion, so it is recommended to be used.
Laryngeal Mask Airway (LMA); Blind insertion; Laryngoscopy; Fiberoptic bronchoscopy; Hemodynamics
The usage frequency and scope of supraglottic airway devices in anesthesia has expanded since the original laryngeal mask airway (LMA) prototype was invented by Dr Archie Brain in the early 1980s. Today, anesthesiologists are spoilt-for-choice with more than thirty options. The LMA Classic Excel™ was introduced to anesthesia practice in 2009; designed with an epiglottic elevating bar and a removable airway connector to facilitate tracheal intubation using the LMA as a conduit. We present a case report of a women diagnosed with papillary carcinoma of thyroid, who underwent bronchoscopic assessment of the trachea and subsequent intubation for an en-bloc dissection and removal of thyroid gland through the LMA Classic Excel™.
Bronchoscopy; intubation; laryngeal mask airway
Background. The aim of this study was to detect the effect of the laryngeal mask airway (LMA) versus the endotracheal tube (ETT) on postoperative nasal bleedings in and outside the operation room (OR) after intranasal surgery. Methods. 134 patients undergoing elective intranasal surgeries were randomly allocated to receive LMA or ETT during general anesthesia. The incidence, episodes, and severity of nasal bleeding were evaluated in the OR and within the postoperative 24 hours in the ward. Furthermore, medical assistance and severe complications were assessed. Results. The overall incidence of postoperative nasal bleeding throughout the observation period was similar between the two groups. The LMA reduced nasal bleeding in the OR. However, outside the OR, the incidence of the first episode of postoperative nasal bleeding in the LMA group was higher than that in the ETT group (difference: −26.5%; 95% CI: −42.2% to −10.7%; P < 0.001). In the LMA group, more patients needed medical assistance (P = 0.029), and the number of assistance was also higher (P = 0.027) in the ward. No severe complications occurred during the observation period. Conclusion. The LMA does not alleviate nasal bleeding conditions and even increases the demands of medical service outside the OR after intranasal surgery, although it reduces epistaxis during extubation.