Impact of airway management strategies on magnetic resonance image quality.

BACKGROUND: Use of general anaesthesia or deep sedation during magnetic resonance imaging (MRI) studies leads to pharyngeal muscle relaxation, often resulting in snoring and subsequent vibrations with head micromotion. Given that MRI is very susceptible to motion, this causes artifacts and image quality degradation. The purpose of our study was to determine the effectiveness of different airway management techniques in overcoming micromotion-induced MRI artifacts. METHODS: After obtaining institutional review board approval, we conducted a retrospective study on the image quality of central nervous system MRI studies in nine patients who had serial MRIs under general anaesthesia. All data were obtained from electronic records. We evaluated the following airway techniques: use of no airway device (NAD); oral, nasal, or supraglottic airway (SGA); or tracheal tube. To assess MRI quality, we developed a scoring system with a combined score ranging from 6 to 30. We used the linear mixed model to account for patient-dependent confounders. RESULTS: We assessed 85 MRI studies from nine patients: 48 NAD, 27 SGA, four oral, four nasal, and two tracheal tube. Arithmetical mean combined scores were 21.6, 27.6, 20.3, 15.3, and 29.5, respectively. The estimated mean combined scores for the NAD and SGA cohorts were 22.0 and 27.3, respectively, showing that SGA use improved the combined score by 5.3 (P<0.0001). CONCLUSIONS: The use of an SGA during MRI studies under general anaesthesia or deep sedation significantly improves image quality.

Archie Brain: celebrating 30 years of development in laryngeal mask airways.

The practice of anaesthesia was revolutionised by the ideas of Archie Brain. The routine use of a facemask to manage the airway was not a hands-free technique, despite the development of various harnesses, and made adequate record-keeping difficult. The tracheal tube was associated with some morbidity, which some felt was unsuitable for day surgery. Brain developed an airway management device that was less stressful to the patient than tracheal intubation, and was, however, as safe as using a facemask and airway. Brain also hoped his device would function for cases where mask ventilation was particularly difficult and thus give anaesthetists a safer alternative to a complex intubation, especially in emergency scenarios.

Retrovirus-mediated wild-type p53 gene transfer to tumors of patients with lung cancer.

A retroviral vector containing the wild-type p53 gene under control of a beta-actin promoter was produced to mediate transfer of wild-type p53 into human non-small cell lung cancers by direct injection. Nine patients whose conventional treatments failed were entered into the study. No clinically significant vector-related toxic effects were noted up to five months after treatment. In situ hybridization and DNA polymerase chain reaction showed vector-p53 sequences in posttreatment biopsies. Apoptosis (programmed cell death) was more frequent in posttreatment biopsies than in pretreatment biopsies. Tumor regression was noted in three patients, and tumor growth stabilized in three other patients.

The laryngeal mask airway: a new standard for airway evaluation in thoracic surgery.

BACKGROUND: Thoracic surgeons typically perform fiberoptic bronchoscopy (FOB) before thoracotomy, usually on the day of the operation after intubation with a single-lumen endotracheal tube (ETT) and before insertion of a double-lumen ETT. This routine requires two laryngoscopies and two intubations. The laryngeal mask airway (LMA) is an airway device developed in England and approved by the Food and Drug Administration in 1991 for clinical use in the United States. It requires neither mask ventilation nor laryngoscopy and allows FOB visualization of the epiglottis, larynx, and entire trachea. We assessed the LMA as an alternative to a single-lumen ETT for FOB before thoracotomy. METHODS: Through prospective assessment, 50 patients underwent FOB after insertion of an LMA before thoracotomy. Pulse rate, blood pressure, ease of insertion of the LMA, quality of FOB, and complications of LMA insertion were assessed. RESULTS: During LMA insertion, blood pressure and pulse rate increased less than 5% from baseline in all patients. The LMA was inserted successfully in all patients within 10 seconds. No complications occurred as a result of LMA insertion. CONCLUSIONS: Insertion of the LMA causes minimal hemodynamic response. From the time of induction of general anesthesia, insertion of the LMA is quick, simple, and safe and eliminates the need for endotracheal intubation with a single-lumen ETT before double-lumen tube insertion. The LMA, in contrast to the ETT, allows a complete survey of the larynx and trachea. The LMA is autoclavable, reusable, and cost effective. Therefore, in patients who require FOB immediately before thoracotomy, LMA use should be the standard for airway evaluation.

Basic surgical techniques in the resection of malignant gliomas.

Although progress is being made in the imaging and medical therapy of malignant gliomas, surgery continues to play a central role in the management of these tumors. Surgery remains necessary for histological diagnosis and relief of mass effect upon adjacent neurological structures. Surgery also achieves cytoreduction of tumor mass, allowing more effective treatment of residual tumor volume. Recent technical advances have made the goal of gross total tumor resection safer and more readily achieved. Surgical techniques and adjuncts that aid the aggressive surgical resection of malignant gliomas will be reviewed.

Use of the intubating LMA-Fastrach in 254 patients with difficult-to-manage airways.

BACKGROUND: The laryngeal mask airway (LMA; LMA North America, Inc., San Diego, CA) has a well-established role in the emergency and elective treatment of patients with difficult-to-manage airways (DA). In this study, the authors report their clinical experience with the intubating LMA (LMA-Fastrach; LMA North America, Inc., San Diego, CA) in 254 patients with different types of DA. METHODS: The authors reviewed the anesthetic and medical records of patients with DA in whom the LMA-Fastrach was used electively or emergently at four institutions from October 1997 through October 2000. In each case, the number of insertion and intubation attempts was recorded. Success rates for blind and fiber optically guided intubation through the LMA-Fastrach were calculated, up to a maximum of five attempts per patient. RESULTS: The LMA-Fastrach was used in 257 procedures performed in 254 patients with DA, including patients with Cormack-Lehane grade 4 views; patients with immobilized cervical spines; patients with airways distorted by tumors, surgery, or radiation therapy; and patients wearing stereotactic frames. Insertion of the LMA-Fastrach was accomplished in three attempts or fewer in all patients. The overall success rates for blind and fiber optically guided intubations through the LMA-Fastrach were 96.5% and 100.0%, respectively. CONCLUSIONS: The LMA-Fastrach was used successfully in a high percentage of patients who presented with a variety of DA. The clinical experience presented herein indicates that this device may be particularly useful in the emergency and elective treatment of patients in whom intubation with a rigid laryngoscope has failed and in the treatment of patients with immobilized cervical spines.