Positive pressure ventilation during fibreoptic intubation: comparison of the laryngeal mask airway, intubating laryngeal mask and endoscopy mask techniques

Randomised controlled trial in cadavers investigating methods for intubation via a supraglottic airway device: Comparison of flexible airway scope guided versus a retrograde technique

OBJECTIVE

A supraglottic airway device (SAD) may be utilised for rescue re-oxygenation following a failed attempt at endotracheal intubation with direct or video laryngoscopy. However, the choice of subsequent method to secure a definitive airway is not clearly established. The aim of the present study was to compare two techniques for securing a definitive airway via the in-situ SAD.

METHODS

A randomised controlled trial was undertaken. The population studied was emergency physicians (EPs) attending a cadaveric airway course. The intervention was intubation through a SAD using a retrograde intubation technique (RIT). The comparison was intubation through a SAD guided by a flexible airway scope (FAS). The primary outcome was time to intubation. The trial was registered with ANZCTR.org.au (ACTRN12621000995875).

RESULTS

Four EPs completed intubations using both methods on four cadavers for a total of 32 experiments. The mean time to intubation was 18.2 s (standard deviation 8.8) in the FAS group compared with 52.9 s (standard deviation 11.7) in the RIT group; a difference of 34.7 s (95% confidence interval 27.1-42.3, P < 0.001). All intubations were completed within 2 min and there were no equipment failures or evidence of airway trauma.

CONCLUSION

Successful tracheal intubation of cadavers by EPs is achievable, without iatrogenic airway trauma, via a SAD using either a FAS or RIT, but was 35 s quicker with the FAS.

Clinical Value of Bronchoscopy in Acute Respiratory Failure

Bronchoscopy may be considered the “added value” in the diagnostic and therapeutic pathway of different clinical scenarios occurring in acute respiratory critically ill patients. Rigid bronchoscopy is mainly employed in emergent clinical situations due to central airways obstruction, haemoptysis, and inhaled foreign body. Flexible bronchoscopy (FBO) has larger fields of acute applications. In intensive care settings, FBO is useful to facilitate intubation in difficult airways, guide percutaneous dilatational tracheostomy, and mucous plugs causing lobar/lung atelectasis. FBO plays a central diagnostic role in acute respiratory failure caused by intra-thoracic tumors, interstitial lung diseases, and suspected severe pneumonia. “Bronchoscopic” sampling has to be considered when “non-invasive” techniques are not diagnostic in suspected ventilator-associated pneumonia and in non-ventilated immunosuppressed patients. The combined use of either noninvasive ventilation (NIV) or High-flow nasal cannula (HFNC) with bronchoscopy is useful in different scenarios; the largest body of proven successful evidence has been found for NIV-supported diagnostic FBO in non-ventilated high risk patients to prevent and avoid intubation. The expected diagnostic/therapeutic goals of acute bronchoscopy should be balanced against the potential severe risks (i.e., cardio-pulmonary complications, bleeding, and pneumothorax). Expertise of the team is fundamental to achieve the best rate of success with the lowest rate of complications of diagnostic and therapeutic bronchoscopic procedures in acute clinical circumstances.

An Unexpectedly Difficult Intubation following Repeated Endoscopy

A 67-year-old man required an urgent laparotomy for a bleeding gastric ulcer. He had undergone three upper gastrointestinal endoscopies over five days since admission to hospital. Tracheal intubation was unexpectedly difficult due to marked supraglottic oedema as well as unfavourable upper airway anatomy. A fibreoptic intubation through a laryngeal mask airway was performed with difficulty. The management of this case of difficult intubation following repeated endoscopy is presented.

Anesthesia for interventional pulmonology procedures: a review of advanced diagnostic and therapeutic bronchoscopy

PURPOSE

Interventional pulmonology is a growing subspecialty of pulmonary medicine with flexible and rigid bronchoscopies increasingly used by interventional pulmonologists for advanced diagnostic and therapeutic purposes. This review discusses different technical aspects of anesthesia for interventional pulmonary procedures with an emphasis placed on pharmacologic combinations, airway management, ventilation techniques, and common complications.

SOURCE

Relevant medical literature was identified by searching the PubMed and Google Scholar databases for publications on different anesthesia topics applicable to interventional pulmonary procedures. Cited literature included case reports, original research articles, review articles, meta-analyses, guidelines, and official society statements.

PRINCIPAL FINDINGS

Interventional pulmonology is a rapidly growing area of medicine. Anesthesiologists need to be familiar with different considerations required for every procedure, particularly as airway access is a shared responsibility with pulmonologists. Depending on the individual case characteristics, a different selection of airway method, ventilation mode, and pharmacologic combination may be required. Most commonly, airways are managed with supraglottic devices or endotracheal tubes. Nevertheless, patients with central airway obstruction or tracheal stenosis may require rigid bronchoscopy and jet ventilation. Although anesthetic approaches may vary depending on factors such as the length, complexity, and acuity of the procedure, the majority of patients are anesthetized using a total intravenous anesthetic technique.

CONCLUSIONS

It is fundamental for the anesthesia provider to be updated on interventional pulmonology procedures in this rapidly growing area of medicine.

Continuous ventilation during intubation through a supraglottic airway device guided by fiberoptic bronchoscopy: a observational assessment

INTRODUCTION

supraglottic airway devices remain, despite advances in video laryngoscopy, important tools in the management of unexpected difficult airways. Intubation through a functioning supraglottic airway device with the aid of a fiberoptic bronchoscope is a well-known technique usually performed in apnoea. With a simple modification, the patient can be ventilated during this procedure.

METHODS

In this observational study, Tracheal intubation Assisted by Bronchoscopy And Sad during Continuous Oxygenation (TABASCO) was performed as part of department training routine in 26 elective, fasted patients. A supraglottic airway device was used as a conduit for an endotracheal tube.

RESULTS

All patients were easily intubated and ventilation was maintained during the procedure. The gap between the outer diameter of the fiberoptic bronchoscope and the inner diameter of the endotracheal tube was more than 2 mm in 25 of 26 patients. Effective ventilation was confirmed by clinical signs, capnography and pressure-volume curves. No signs of airtrapping occurred.

DISCUSSION

No adverse events were observed during this form of airway management in this small series of elective and fasted patient when performed by an anaesthesiologist experienced in fiberoptic intubation. A gap between fiberoptic bronchoscope and endotracheal tube inner lumen seems to be prerequisite for easy ventilation through the supraglottic airway. In trained hands, this technique can be a means to secure an airway with an intubating bronchoscope without pausing ventilations. A prerequisite for this is a well-functioning supraglottic airway device.

Tracheal Intubation with Aura-i and aScope-2: How to Minimize Apnea Time in an Unpredicted Difficult Airway

The supraglottic airway's usefulness as a dedicated airway is the subject of continuing development. We report the case of an obese patient with unpredicted difficult airway management in which a new “continuous ventilation technique” was used with the Aura-i laryngeal mask and the aScope-2 devices. The aScope-2/Aura-i system implemented airway devices for the management of predictable/unpredictable difficult airway. The original technique required the disconnection of the mount catheter from Aura-i, the introduction of the aScope-2 into the laryngeal mask used as a conduit for video assisted intubation and then towards the trachea, followed by a railroading of the tracheal tube over the aScope-2. This variation in the technique guarantees mechanical ventilation during the entire procedure and could prevent the risk of hypoventilation and/or hypoxia.

Difficult airway intubation with flexible bronchoscope

BACKGROUND AND OBJECTIVE

To describe the efficacy and safety of a flexible bronchoscopy intubation (FBI) protocol in patients with difficult airway.

METHOD

We reviewed the medical records of patients diagnosed with difficult airway who underwent flexible bronchoscopy intubation under spontaneous ventilation and sedation with midazolam and fentanyl from March 2009 to December 2010.

RESULTS

The study enrolled 102 patients, 69 (67.7%) men and 33 (32.3%) women, with a mean age of 44 years. FBI was performed in 59 patients (57.8%) with expected difficult airway in the operating room, in 39 patients (38.2%) in the Intensive Care Unit (ICU), and in 4 patients (3.9%) in the emergency room. Cough, decrease in transient oxygen saturation, and difficult progression of the cannula through the larynx were the main complications, but these factors did not prevent intubation.

CONCLUSION

FBI according to the conscious sedation protocol with midazolam and fentanyl is effective and safe in the management of patients with difficult airway.

Flexible bronchoscopy assisted by noninvasive positive pressure ventilation

Noninvasive positive pressure ventilation is an alternative to intubation in critically ill patients with respiratory insufficiency or poor gas exchange who may require flexible bronchoscopy for diagnostic or therapeutic purposes. This ventilatory technique might help decrease the risk of bronchoscopy-related complications in patients with refractory hypoxemia, postoperative respiratory distress, severe emphysema, obstructive sleep apnea, and obesity hypoventilation syndrome and allows bronchoscopic assessment of patients with severe dyspnea from expiratory central airway collapse. In this review, the physiological rationale, indications, contraindications, techniques, and monitoring requirements for flexible bronchoscopy assisted by noninvasive positive pressure ventilation are described, with an emphasis on the role of critical care nurses in this procedure.

Intubating condition, hemodynamic parameters and upper airway morbidity: A comparison of intubating laryngeal mask airway with standard direct laryngoscopy

Background:

Intubating Laryngeal Mask Airway (ILMA) is a relatively new device designed to have better intubating characteristics than the standard Laryngeal Mask Airway. This study was designed to compare Intubating Laryngeal Mask with standard Direct Laryngoscopy (DLS), taking into account ease of intubation, time taken for intubation, success rate of intubation, hemodynamic responses and upper airway morbidity.

Materials and Methods:

Sixty patients, ASA I or II, of age between 20 and 60 years, were enrolled in this prospective and randomized study. They were randomly allocated to one of the two groups: group ILMA, Intubating Laryngeal Mask Airway; group DLS, Direct Laryngoscopy. The patients were intubated orally using either equipment after induction of general anesthesia.

Results and Conclusions:

DLS is comparatively a faster method to secure tracheal intubation than Intubating Laryngeal Mask. ILMA offers no advantage in attenuating the hemodynamic responses compared to direct laryngoscope. The success rate of intubation through Intubating Laryngeal Mask is comparable with that of DLS. The upper airway morbidity and mean oxygen saturation are comparable in both the groups.

Laryngeal mask airways have a lower risk of airway complications compared with endotracheal intubation: a systematic review

PURPOSE

The purpose of the present study was to determine whether, in patients undergoing general anesthesia, those provided with a laryngeal mask airway (LMA) have a lower risk of airway-related complications than those undergoing endotracheal intubation.

MATERIALS AND METHODS

A systematic review of randomized prospective controlled trials was done to compare the risk of airway complications with an LMA versus an endotracheal tube (ETT) in patients receiving general anesthesia. Two independent reviewers identified 29 randomized prospective controlled trials that met the predetermined inclusion and exclusion criteria. The data for each individual outcome measure were combined to analyze the relative risk ratios (RRs). The Cochrane RevMan software was used for statistical analysis.

RESULTS

When an ETT was used to protect the airway, a statistically significant greater incidence of hoarse voice (RR 2.59, 95% confidence interval [CI] 1.55 to 4.34), a greater incidence of laryngospasm during emergence (RR 3.16, 95% CI 1.38 to 7.21), a greater incidence of coughing (RR 7.12, 95% CI 4.28 to 11.84), and a greater incidence of sore throat (RR 1.67, 95% CI 1.33 to 2.11) was found compared with when an LMA was used to protect the airway. The differences in the risk of regurgitation (RR 0.84, 95% CI 0.27 to 2.59), vomiting (RR 1.56, 95% CI 0.74 to 3.26), nausea (RR 1.59, 95% CI 0.91 to 2.78), and the success of insertion on the first attempt (RR 1.08, 95% CI 0.99 to 1.18) were not statistically significant between the 2 groups.

CONCLUSIONS

For the patients receiving general anesthesia, the use of the LMA resulted in a statistically and clinically significant lower incidence of laryngospasm during emergence, postoperative hoarse voice, and coughing than when using an ETT. The risk of aspiration could not be determined because only 1 study reported a single case of aspiration, which was in the group using the ETT.

Facemask pressure-controlled ventilation in children: what is the pressure limit?

BACKGROUND

In this study, we sought to determine the level of inspiratory pressures allowing adequate and safe ventilation without any risk of gastric insufflation (GI) in children according to age.

METHODS

One hundred children, aged 1 day to 16 years, ASA physical status I to II, scheduled for general anesthesia were studied prospectively. After induction of anesthesia, children's lungs were ventilated with pressure-controlled ventilation. The initial inspiratory pressure was 10 cm H(2)O and was increased by steps of 5 cm H(2)O, up to a maximum of 25 cm H(2)O. At each step, GI was detected by epigastric auscultation. The recorded data were age and weight. At each step, the inspiratory pressure, the respiratory rate, the expired tidal volume, the minute ventilation, and the occurrence of GI were also recorded.

RESULTS

GI occurred in 78 children. GI occurred in 95% of children younger than 1 year, in 93% of children aged 1 to 5 years, and 56% of children older than 5 years (P = 0.001). The pressure threshold at which GI occurred increased with age: the younger the child, the lower the GI pressure threshold. Tidal volume increased with inspiratory pressure, but at >15 cm H(2)O, tidal volume did not change significantly.

CONCLUSION

The inspiratory pressure threshold at which GI can occur depends on age. It is low in infants and increases with age. In most cases, proper ventilation without GI was obtained with an inspiratory pressure </=15 cm H(2)O. Increasing inspiratory pressure above this threshold results in an increase in GI and no change in tidal volume.

Fibreoptic intubation using three airway conduits in a manikin: the effect of operator experience

In a randomised cross-over study, 72 anaesthetists (24 Senior House Officers, 24 Specialist Registrars and 24 Consultants) attempted to place a fibreoptic scope in the trachea of a manikin using three airway conduits: the Berman airway, the LMA Classic(trade mark) and the intubating laryngeal mask airway. The time for insertion of the airway conduit, delivery of two breaths and fibreoptic scope placement in the trachea was the primary endpoint. These overall times were significantly shorter (median [interquartile range]) using the LMA Classic (36 [28-45]) than via the intubating laryngeal mask (54 [42-79]) and the Berman airway (45 [33-80]), p < 0.0001. Senior House Officers were significantly slower than both Specialist Registrars and Consultants (p < 0.0001). The LMA Classic was considered to be the easiest conduit to use for fibreoptic scope placement by all grades of anaesthetists. We conclude that the LMA Classic is the most effective conduit for fibreoptic scope placement especially for anaesthetists with limited experience in its use.

Management of tracheal deformity during intubation: a case report

Failure or difficulty in intubating the trachea can be either due to inability to visualize the glottis or some pathology at the level of or below the cords. This report describes a case of difficult intubation suspected of being related to neck scarring from previous surgery. Computed tomography (CT) was used to evaluate the patient's airway and revealed upper tracheal angulation. We describe a method to secure the airway in this patient with a two-person technique by rotating an oral endotracheal tube 180 degrees counterclockwise to adjust to the curvature of the trachea. Problems with intubation should be anticipated in patients with scarring of the neck, and equipment for aiding intubation should be on hand. Furthermore, we found that CT contributed to the assessment of the difficulty of intubation in this kind of patient.

Fibre-optic intubation teaching in sedated patients with anticipated difficult intubation

BACKGROUND AND OBJECTIVES

The objective of the study was to assess the safety of training fibre-optic intubation performed under propofol light general anaesthesia in patients with an anticipated difficult intubation.

METHODS

Patients with ear, nose and throat cancer having at least two criteria for anticipated difficult intubation and scheduled for fibre-optic intubation were included prospectively. In 26 patients, intubation was performed by an anaesthesia resident (under senior supervision), whereas in 20 patients, it was performed by a senior anaesthesiologist. All patients received propofol light general anaesthesia adjusted to maintain both loss of consciousness and spontaneous ventilation.

RESULTS

Of the 46 patients, 45 had successful fibre-optic intubation, and one needed a rescue procedure because of hypoxaemia. Residents failed to intubate four patients, who were easily intubated by the senior. Episodic hypoxaemia (SPO2 < 90%) occurred in three patients in each group. No statistically significant difference was found between junior and senior neither on the duration of the procedure (9.3 +/- 4.9 vs. 7.5 +/- 4.0 min) nor on the propofol consumption (197 +/- 130 vs. 193 +/- 103 mg) or the ETCO2 at the end of the procedure (36 +/- 6 vs. 38 +/- 6 mmHg), respectively.

CONCLUSION

Teaching fibre-optic tracheal intubation in patients with anticipated difficult intubation and sedated with propofol did not increase morbidity significantly compared with an experienced anaesthesiologist. Fibre-optic intubation under propofol light general anaesthesia could be safely performed by a resident as long as a senior anaesthesiologist is permanently present, spontaneous ventilation is maintained and a rescue oxygenation technique is immediately available.

Low-skill fibreoptic intubation: use of the Aintree Catheter with the classic LMA

We describe a series of patients in whom anaesthetists - many of whom were trainees and had no prior experience of using the Aintree Intubation Catheter - successfully intubated the tracheas of patients in whom conventional attempts at intubation had failed. This was achieved by passing a fibrescope loaded with an Aintree Intubation Catheter through a classic Laryngeal Mask Airway (cLMA), which had already been placed to maintain the patient's airway.

Difficult Airway Society guidelines for management of the unanticipated difficult intubation

Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non-obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow-charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flow-charts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS.

DISCLAIMER

It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.

Training in airway management

Management of the airway is central to the practice of anaesthesia, yet trainees frequently feel poorly trained in this area. A large range of skills needs to be acquired, but there are often problems providing training on live patients. We review the different modalities available for training and assessment in airway management.

Insertion of the transesophageal echocardiography probe via endoscopy mask

IMPLICATIONS

Transesophageal echocardiography (TEE) has not been used during airway manipulation to assess the occasional occurrence of hemodynamic instability that occurs especially in cardiac patients. We describe a new technique using an endoscopy mask to perform TEE monitoring during airway manipulation with a large concentration of supplemented oxygen.