Laryngeal mask and reduction of nasal bone fractures

A retrospective study was conducted in 116 patients who underwent anesthesia for reduction of nasal fracture under laryngeal mask for ventilation and protection of the airways. One patient had secondary intubation due to difficult insertion of the laryngeal mask. No episode of hypoxemia related to blood inhalation occurred. The laryngeal mask may be proposed to maintain the airway in this surgical procedure.     

The importance of the laryngeal mask in the difficult intubation and early experience with the intubating laryngeal mask airway--ILMA--Fastrach

The conventional laryngeal mask airway ("Standard" laryngeal mask airway SLMA is of outstanding importance in the management of the difficult airway. The intubating laryngeal mask airway (ILMA, commercial name Fastrach) has become available recently. First results indicate that the excellent ventilation characteristics of SLMA are maintained, but in addition blind intubation is successful in more than 90% of patients with normal anatomy as well as with difficult intubation. PURPOSE: We present the use of ILMA, compare the potential of the two laryngeal mask types in difficult intubation by own results, present the results of a first symposium on the ILMA held at Jersey in December 1996, the role of the SLMA in difficult intubation as proposed by the American and the French Societies of Anaesthesiology, as well as an outlook on possible uses of the ILMA in the light of the available results. METHODS: The SLMA was prospectively used between 1992 and 1997 for 66 operations in 55 patients with difficult intubation (laryngoscopic view Cormack grade IV, n = 24; grade III, n = 35; grade < III, n = 7). 48 operations were performed after resection of a facial carcinoma, 14 on patients without carcinoma who could not be intubated conventionally, 5 on patients with periglottic pathology, and on 50 normals. The ILMA was used on 150 patients between 11/1996 and 11/1997, 106 had normal anatomy, 33 were difficult to intubate (Cormack grade IV, n = 12; grade III, n = 21), 24 had a reduced mouth opening of < or = 2.5 cm awake, 14 of these also were difficult to intubate. RESULTS: Ventilation was superior to a face mask (FM): (SLMA: ventilation not sufficient (SaO2 < 90% > 30 sec) with a FM in 22 operations compared to 5 with a SLMA; ILMA: ventilation not sufficient with a FM in 7 operations compared to 3 with an ILMA). Blind intubation through a SLMA had a success rate of 50% and 34% in 50 normals and in 32 operations with difficult intubation after a mean of 2.6 intubation attempts each. The success rate per intubation attempt for the SLMA was 22% in normals and 13% in difficult intubation. Through an ILMA, blind intubation was successful in 92% of normals, 5 of them with immobile spine, in 91% in patients with difficult intubation, and in 83% in patients with reduced mouth opening. The success rate per intubation attempt was 60% in normals, 46% in difficult intubation, and 46% in reduced mouth opening, with a success rate for the first intubation attempt of 57%. This compares favourably with results presented at the Jersey symposium in 554 patients. CONCLUSION: The ILMA maintains the superb ventilation potential of a SLMA in difficult intubation but doubles the success rate of blind intubation irrespective of anatomical difficulties, with a 50% success rate during the first intubation attempt. Possible uses of the ILMA may be in difficult intubation situations including immobile spine, in cannot ventilate--cannot intubate situations comparable to a SLMA with an improved chance of successful intubation, and perhaps as a device for ventilation and intubation for untrained people. The use of the ILMA can be trained during everyday practice. Expert assessment of successful endotracheal tube position is mandatory.     

The laryngeal mask--a valuable instrument for cases of difficult intubation in children. Anesthesiologic management in the presence of Pierre-Robin syndrome

In cases of craniofacial and mandibulofacial malformations, which are mostly treated during childhood, difficult intubation conditions must generally be expected. In such cases, the laryngeal mask airway (LMA) an alternative instrument for use in endotracheal intubation is a new aid for ventilation. In certain instances, it can be used alone to induce general anaesthesia. Reports of endotracheal intubation by means of the LMA in adults have also been published. CASE REPORT: In our case, a 6-year-old boy with Pierre-Robin syndrome (triad: micrognathia, broad palatoschisis, glossoptosis) needed dental resetting. After induction of anaesthesia in this very cooperative boy with thiopentone and fluothane and relaxation with succinylcholine, it was not possible to examine the hypopharynx by laryngoscopy preparatory to nasal intubation as usual. Repeated blind attempts at nasal intubation (again with spontaneous breathing) failed, as did the attempt at fibreoptic bronchoscopic intubation, because of the narrow anatomical conditions. Finally, a laryngeal mask airway (LMA; size 2) was introduced, and as a result of this ventilation was achieved. However, endotracheal intubation was required for performance of the surgical resetting. With the fibreoptic bronchoscope, we could verify the central position of the LMA over the glottis. A tracheal tube (size 4) was inserted across the laryngeal airway without optic control. The tube connector was disconnected and a normal guide inserted into the tube to remove the LMA. The dental resetting was also performed by oral intubation. CONCLUSION: Therefore, the LMA is not only a ventilation aid, but also a valuable tool in difficult intubation conditions. In our opinion, it is necessary to provide this tool in every anaesthetic unit.     

Nasal fibreoptic tracheal intubation in anaesthetised patients breathing via a modified laryngeal mask airway

A modified laryngeal mask airway was used to facilitate nasotracheal intubation with a fibreoptic laryngoscope. A size 4 laryngeal mask airway was modified by creating a defect at the base of the stem and removing the bars to allow passage of the fibreoptic laryngoscope from the nasopharynx to the larynx. The laryngeal mask airway cuff was split and the cut edges were sealed with silicone. This design allowed the cuff to function normally and allowed removal of the split laryngeal mask airway after the tracheal tube had been 'railroaded' into place. Thirty-four patients were studied. The split laryngeal mask airway was easily inserted with satisfactory airway maintenance in 32 patients. Nasal airway endoscopy and laryngoscopy were successfully achieved with the split laryngeal mask airway in place in 31 of 32 patients. Railroading the tracheal tube over the fibreoptic laryngoscope with the split laryngeal mask airway in place was successful in all 31 of these patients. This prototype split laryngeal mask airway allows good airway maintenance while fibreoptic nasotracheal intubation is performed.     

Enhanced protein synthesis in the ipsilateral substantia nigra following middle cerebral artery occlusion in the rat

The purpose of this randomised single blinded study was to determine the optimal size of laryngeal mask airway in the normal adult population, to test the validity of the current selection criteria and to determine if any externally measured anatomical variable correlated with optimal size. In each of 30 apnoeic anaesthetised adults weighting less than 100 kg, size 3, 4 and 5 laryngeal mask airways were inserted in random order by a skilled user and the cuff inflated to a standard pressure (60 cm H2O). Optimal size was based on four criteria in order of priority: number of attempts at placement, oropharyngeal leak pressure, fiberoptic score and percentage of vocal cords seen. The size 5 laryngeal mask airway was optimal in 19/30 and the size 4 in 11/30. In no patient was the size 3 the optimal fit. Oropharyngeal leak pressure was significantly higher for each progressively large size and the fiberoptic view was significantly better for the size 4 and size 5. There was no significant predictive value in any externally measured anatomical variable, but height was the most useful. The best current selection strategy was to choose a size 5 for males and size 4 for females. Potentially useful new strategies may be to use the size 5 in all adults, or a size 5 > or = 165 cm in height and size 4 for < 165 cm. We conclude that predicting the optimal size of laryngeal mask airway for individual adult patients is complex. The best size selection strategies involve use of the size 4 and 5 laryngeal mask airways in adults.     

Fetal unilateral cleft lip and palate: detection of enzymic anomalies in the amniotic fluid

BACKGROUND: Tracheal intubation frequently results in an increase in respiratory system resistance that can be reversed by inhaled bronchodilators. The authors hypothesized that insertion of a laryngeal mask airway would be less likely to result in reversible bronchoconstriction than would insertion of an endotracheal tube. METHODS: Fifty-two (45 men, 7 women) patients were randomized to receive a 7.5-mm (women) or 8-mm (men) endotracheal tube or a No. 4 (women) or No. 5 (men) laryngeal mask airway. Anesthesia was induced with 2 microg/kg fentanyl and 5 mg/kg thiopental, and airway placement was facilitated with 1 mg/kg succinylcholine. When a seal to more than 20 cm water was verified, respiratory system resistance was measured immediately after airway placement. Inhalation anesthesia was begun with isoflurane to achieve an end-tidal concentration of 1% for 10 min. Respiratory system resistance was measured again during identical conditions. RESULTS: Among patients receiving laryngeal mask airways, the initial respiratory system resistance was significantly less than among patients with endotracheal tubes (9.2+/-3.3 cm water x 1(-1) x s(-1) [mean +/- SD] compared with 13.4+/-9.6 cm water x 1(-1) x s(-1); P < 0.05). After 10 min of isoflurane, the resistance decreased to 8.6+/-3.6 cm water x 1(-1) x s(-1) in the endotracheal tube group but remained unchanged at 9.1+/-3.3 cm water x 1(-1) x s(-1) in the laryngeal mask airway group. The decrease in respiratory system resistance in the endotracheal tube group of 4.7+/-7 cm water x 1(-1) x s(-1) was highly significant compared with the lack of change in the laryngeal mask airway group (P < 0.01). CONCLUSIONS: Resistance decreased rapidly only in patients with endotracheal tubes after they received isoflurane, a potent bronchodilator, suggesting that reversible bronchoconstriction was present in patients with endotracheal tubes but not in those with laryngeal mask airways. A laryngeal mask airway is a better choice of airway to minimize airway reaction.     

Management of difficult airway during induction of anesthesia in a patient with Hallermann-Streiff syndrome

An 18-year-old female with Hallermann-Streiff syndrome underwent the fixation of prolapsus recti. She had significant microgenia, mental retardation and pharyngeal airway stenosis. During induction of anesthesia with halothane and nitrous oxide, severe upper airway obstruction and respiratory depression occurred. The mask ventilation with jaw lift maneuver was impossible. Lowering anesthetic level restored her spontaneous breathing and airway patency. Although the direct laryngoscopic view under light anesthesia with halothane was limited to the epiglottic tip, blind orotracheal intubation using stylet was accomplish after several attempts. At the end of anesthesia, the tracheal tube was extubated after the patient had become fully awake and had recovered completely from neuromuscular blockade monitored by electromyography.     

Difficult intubation and brain-stem anaesthesia

PURPOSE: To present a case of difficult intubation with brainstem anaesthesia after retrobulbar block with bupivacaine and lidocaine and sedation with midazolam and to point out that close monitoring and timely treatment is important in preventing an unfavourable outcome. CLINICAL FEATURES: An 82-yr-old man with treated hypertension and stable angina was scheduled for cataract extraction. Physical examination revealed a class 2 airway. He had a retrobulbar block after topical tetracaine drops, with bupivacaine 0.5% and lidocaine 2% with hyaluronidase under sedation with 1 mg midazolam. Five minutes after the block, respiration slowed, he became unresponsive and oxygen saturation decreased to 80%. Immediate ventilation with mask without additional oxygen improved saturation. Attempted tracheal intubation failed: the epiglottis could not be visualized despite flaccid jaw and extremities. A laryngeal mask airway was placed which was leaking and adequate ventilation could not be achieved but a second laryngeal mask airway was placed successfully. CONCLUSION: This case emphasizes the need for dose monitoring and personnel capable of managing the difficult airway when intra-orbital anaesthesia is used.     

The intubating laryngeal mask airway: an initial assessment of performance

A new prototype of the laryngeal mask airway (LMA), the intubating laryngeal mask airway (ILMA), was used to facilitate tracheal intubation in 100 fasted patients presenting for elective surgery. Alignment of the ILMA with the larynx was assessed fibreoptically before intubation without the investigator performing the intubation being aware of the view score. Ease of intubation correlated with the view obtained and with the degree of manipulation of the ILMA needed to achieve tracheal intubation. Intubation was successful in 93 patients. Of the seven intubation failures, five occurred in the first 20 patients. Conventional connection to the breathing system and ventilation of the lungs of the patients were possible throughout the intubation procedure.     

The glottic aperture seal airway: a new ventilatory device

BACKGROUND: None of the presently used airway devices are ideal regarding ease of insertion, alignment with the laryngeal inlet, and provision of a high-pressure seal from the environment. The purpose of this study was to determine, in awake volunteers, the performance of a new ventilatory device, the glottic aperture seal airway, regarding ease of insertion, alignment with the laryngeal inlet, and forced exhalation seal pressure (PFES). METHODS: The glottic aperture seal airway consists of a curved tubular component that ends in the middle of an elliptical foam cushion glottic component. The posterior surface of the foam has a curved flexible plastic backing, which imparts a 60 degree angle between the proximal half and the distal half of the foam cushion. When the glottic aperture seal airway is properly in situ in a supine patient, the proximal half of the foam cushion is opposite the laryngeal inlet. The posterior surface of the plastic backing has a balloon attached to it. Inflation of the balloon presses the ventilation hole and foam cushion up against the laryngeal inlet, thereby creating a seal from the environment. Using the laryngeal mask airway as a control device, the glottic aperture seal airway was tested for time and ease of insertion, fiberoptic alignment with the laryngeal inlet, and PFES in 18 lightly sedated and locally anesthetized volunteers. RESULTS: The glottic aperture seal and laryngeal mask airways were inserted with equal ease and speed. The fiberoptic alignment with the larynx was excellent for both the glottic aperture seal and laryngeal mask airways. In all volunteers, the mean +/- SD PFES values at 0-, 10-, 20-, 30-, and 40-ml balloon inflation volumes of the glottic aperture seal airway were 23.4 +/- 11.8, 29.6 +/- 12.4, 42.7 +/- 12.5, 56.9 +/- 5.6, and 60 +/- 0 cm H2O, respectively; the PFES at > or = 20 ml balloon inflation volume of the glottic aperture seal airway was significantly greater than with the laryngeal mask airway (19.4 +/- 6.7 cm H2O, P < 0.01). A PFES of > or =60 cm H2O was achieved with the glottic aperture seal airway in all volunteers (n = 2 at 10 ml, n = 3 at 20 ml, n = 9 at 30 ml, and n = 4 at 40 ml). The glottic aperture seal airway did not cause any trauma. CONCLUSION: In awake volunteers, the glottic aperture seal and laryngeal mask airways were equally easy to insert and position. The glottic aperture seal airway was capable of achieving a higher PFES than the laryngeal mask airway.     

Obstetric analgesia-anesthesia: state of the art

Based on our results and experiences, we consider the laryngeal mask anaesthesia a recommendable alternative to endotracheal intubation anaesthesia for adenotomies in children. Prerequisites with regard to the highest possible safety for the patient are specialist's knowledge, close anaesthesiological-otolaryngological cooperation and continuous clinical and apparative monitoring in order to detect possible accidental dislocations of the laryngeal mask without any delay. Using the laryngeal mask, disadvantages of endotracheal intubation, such as lesions of the vocal cords and damages to the tracheal mucous membrane can be avoided and the total time of narcosis can be reduced on average by about five minutes, particularly by shortening the recovery time of anaesthesia.     

Use of adenosine in patients hospitalized in a university medical center

A 54-year old woman was scheduled for thoracotomy for excision of a tumor of the left upper lobe. Reduced thyromental distance and thyroid enlargement were identified by the preoperative physical examination and inability to visualize the larynx was encountered during direct laryngoscopy. A 37-Fr left sided double lumen tube was inserted in trachea with great difficulty after three failed attempts. One lung anesthesia underwent uneventfully and postoperatively it was decided to exchange the double lumen tube to a single lumen tracheal tube. After the extubation, five failed attempts of reintubation were performed. A laryngeal mask airway (LMA) size 3 was passed easily achieving an airtight airway. The patient underwent an uneventful prolonged (105 min) weaning via the LMA which was left in place until the patient regained full consciousness. Peripheral oxygen saturation remained greater than 95% throughout the airway manipulation. LMA insertion is an easy non-invasive technique and should be considered whenever airway management proves difficult.     

Usefulness of the intubating laryngeal mask airway for cases with predicted difficult intubation

We evaluated the usefulness of the intubating laryngeal mask airway (ILMA) in patients who were predicted to have possible difficult airway. Patients with possible difficult airway were defined as those with limited head extension, Mallampati's classification of grade IV, thyro-mental distance < 4 cm, or Cormack grade III-IV on the laryngoscopy. The control group was consisted of the patients without these conditions or impaired mouth opening. Insertion of the ILMA was successfully performed in all patients of both groups. In the group of possible difficult airway, 83% of patients were intubated through the ILMA successfully, and in the control group, 86%. We conclude that the ILMA may become an additional tool in patients with difficult intubation.     

The unanticipated difficult airway with recommendations for management

PURPOSE: To review the current literature and generate recommendations on the role of newer technology in the management of the unanticipated difficult airway. METHODS: A literature search using key words and filters of English language and English abstracted publications from 1990-96 contained in the Medline, Current Contents and Biological Abstracts databases was carried out. The literature was reviewed and condensed and a series of evidence-based recommendations were evolved. CONCLUSIONS: The unanticipated difficult airway occurs with a low but consistent incidence in anaesthesia practice. Difficult direct laryngoscopy occurs in 1.5-8.5% of general anaesthetics and difficult intubation occurs with a similar incidence. Failed intubation occurs in 0.13-0.3% general anaesthetics. Current techniques for predicting difficulty with laryngoscopy and intubation are sensitive, non-specific and have a low positive predictive value. Assessment techniques which utilize multiple characteristics to derive a risk factor tend to be more accurate predictors. Devices such as the laryngeal mask, lighted stylet and rigid fibreoptic laryngoscopes, in the setting of unanticipated difficult airway, are effective in establishing a patient airway, may reduce morbidity and are occasionally lifesaving. Evidence supports their use in this setting as either alternatives to facemask and bag ventilation, when it is inadequate to support oxygenation, or to the direct laryngoscope, when tracheal intubation has failed. Specifically, the laryngeal mask and Combitube have proved to be effective in establishing and maintaining a patent airway in "cannot ventilate" situations. The lighted stylet and Bullard (rigid) fibreoptic scope are effective in many instances where the direct laryngoscope has failed to facilitate tracheal intubation. The data also support integration of these devices into strategies to manage difficult airway as the new standard of care. Training programmes should ensure graduate physicians are trained in the use of these alternatives. Continuing medical education courses should allow physicians in practice the opportunity to train with these alternative devices.     

Laryngoscopy and fibreoptic intubation in acromegalic patients

Acromegaly is recognized as a cause of difficulty in airway management and tracheal intubation. We evaluated prospectively the conditions for laryngoscopy and fibreoptic intubation in 15 acromegalic patients. Each patient served as his or her own control. Ventilation of the lungs with a face mask was successful in all patients. In five of 15 patients the vocal cords could not be seen using the Macintosh laryngoscope with a size 5 blade. Difficult laryngoscopy was associated significantly with the number of attempts required to see the vocal cords with the fibrescope (P < 0.01, Spearman rank correlation). The larynx could not be seen with both techniques in one patient, and the trachea was intubated blindly with the help of an introducer. Our results showed that fibreoptic intubation may prove difficult or fail in acromegalic patients. Difficulties in seeing the vocal cords with a fibrescope were present most often in patients who also had probable intubation difficulties with a rigid laryngoscope.     

Laryngeal mask airway position and the risk of gastric insufflation

A potential risk of the laryngeal mask airway (LMA) is an incomplete mask seal causing gastric insufflation or oropharyngeal air leakage. The objective of the present study was to assess the incidence of LMA malpositions by fiberoptic laryngoscopy, and to determine their influence on gastric insufflation and oropharyngeal air leakage. One hundred eight patients were studied after the induction of anesthesia, before any surgical manipulations. After clinically satisfactory LMA placement, tidal volumes were increased stepwise until air entered the stomach, airway pressure exceeded 40 cm H2O, or air leakage from the mask seal prevented further increases in tidal volume. LMA position in relation to the laryngeal entrance was verified using a flexible bronchoscope. The overall incidence of LMA malpositions was 40% (43 of 108). Gastric air insufflation occurred in 19% (21 of 108), and in 90% (19 of 21) of these patients, the LMA was malpositioned. Oropharyngeal air leakage occurred in 42%, and was independent of LMA position. We conclude that clinically unrecognized LMA malposition is a significant risk factor for gastric air insufflation. Implications: Routine placement of laryngeal mask airways does not require laryngoscopy. In our study, fiberoptic verification of mask position revealed suboptimal placement in 40% of cases. Such malpositioning considerably increased the risk of gastric air insufflation.     

Physical-mechanical effects of Nd:YAG laser on the surface of sound dental enamel

We present our experience with 55 children in which we performed flexible fiberoptic bronchoscopy (FFB) using an Olympus BF3C20 instrument and by using sedation and local anaesthesia or laryngeal mask airway. Indications for performing this procedure were stridor, opportunist or recurrent pneumonia, persistent atelectasis, a suspected foreign body, confirmation of endobronchial tuberculosis and evaluation of tracheostomy. In 70% of the cases, the diagnosis was made by the FFB and 14 cases were normal. One child with severe hypoxia presented respiratory arrest and need intubation. Our results suggest that FFB is safe, has advantages over rigid bronchoscopy, avoids general anaesthetic and with laryngeal mask airway is possible to perform in patients of every age.     

The intubating laryngeal mask airway (ILMA): initial experience in Singapore

We have evaluated the intubating laryngeal mask airway (ILMA) for ventilation and for blind tracheal intubation. After induction of anaesthesia with fentanyl 1 microgram kg-1 and propofol 3 ml kg-1, the ILMA was placed successfully on the first attempt in all 100 patients. After administration of atracurium 0.5 mg kg-1, blind tracheal intubation was successful in 97% of patients--50% on the first attempt, 42% on the second and 5% on the third. Success was improved by pulling the metal handle of the ILMA towards the intubator in an "extension" manoeuvre, if intubation was not possible on the first attempt. These findings confirm the effectiveness of the ILMA in an Asian population.     

Induction of anesthesia and tracheal intubation with sevoflurane in adults

BACKGROUND: The speed, quality, and cost of mask induction of anesthesia and laryngeal mask airway insertion or tracheal intubation were studied in young non-premedicated volunteers given high inspired concentrations of sevoflurane (6 to 7%). METHODS: Twenty healthy persons who were 19 to 32 years old participated three times, received 6 l/min fresh gas flow, and were randomized to receive 6 to 7% sevoflurane in 66% nitrous oxide/28% oxygen by face mask until tracheal intubation (treatment 1) or until laryngeal mask airway insertion (treatment 3), or 6 to 7% sevoflurane without nitrous oxide to tracheal intubation (treatment 2). Participants exhaled to residual volume and took three vital capacity breaths of the gas mixture; thereafter ventilation was manually assisted. The time of exposure to the inhaled gas was varied for consecutive participants. It was either increased or decreased by 30-sec increments based on the failure or success of the preceding volunteer's response to laryngoscopy and intubation after a preselected exposure time. Failure was defined as poor jaw relaxation, coughing or bucking, or inadequate vocal cord relaxation. RESULTS: Loss of the lid-lash reflex in unpremedicated young volunteers was achieved in 1 min and did not differ among groups. Average time (and 95% confidence interval) for acceptable conditions for LMA insertion was achieved in 1.7 (0.7 to 2.7) min, and all participants had an immediate return of spontaneous ventilation. The time for acceptable tracheal intubating conditions after manual hyperventilation by mask was 4.7 (3.7 to 5.7) min and 6.4 (5.1 to 7.7) min in treatments 1 and 2, respectively. There were no cases of increased secretions or laryngospasm. The incidence of breath holding and expiratory stridor ("crowing") was 7.5% and 25%, respectively, during treatment 1 and 15% and 40%, respectively, during treatment 2. CONCLUSIONS: The induction of anesthesia to loss of lid reflex in young non-premedicated adults approaches the speed of intravenous induction techniques. No untoward airway responses were noted during mask induction of anesthesia with a three-breath technique. In response to intubation, no adverse airway responses, including jaw tightness, laryngospasm, and excessive coughing or bucking, occurred in participants whose duration of mask administration of sevoflurane met the appropriate times (as determined in this study).