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.     

The cataract extraction-refraction-implantation technique for IOL power calculation in difficult cases

We present an unusual case of polydactyly of the thumb. The patient, despite having a fully developed nail bed, had a duplication at the metacarpophalangeal level consisting of a single bony phalanx. The Wassel classification of polydactyly, which is the most commonly cited classification scheme, does not include this particular anomaly. In addition, there has been no reference to this type of polydactyly in the literature.     

Energy conservation behavior: The difficult path from information to action.

Presents a social-psychological model of energy-use behavior that draws on behavioral and social research to explain influence processes and behavioral change related to energy conservation behavior. The model consists of 2 interacting sets of factors: psychological factors that refer to how information is processed by individual decision makers and positional factors that relate to characteristics of the decision makers' situations that support or constrain action. Suggestions for maximizing the effectiveness of informational appeals to conserve energy by convincing the consumer that a pay-off will result from the use of energy conserving devices are discussed. It is suggested that the adoption of a conservatory attitude is influenced by the vividness of the argument to conserve energy, the credibility of the source, the understanding and retention of the message, and the degree to which an individual is able and willing to install conservation devices in his/her home. Alternatives to informational appeals through mass media to encourage energy conservation are proposed. (47 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The univent tube can facilitate difficult intubation in a patient undergoing thoracoscopy

A case of a subcutaneous haemangioma of the hand clinically mimicking a glomus tumour is described. Other discrete small hand tumours that may present with the triad of pain, tenderness and cold intolerance are discussed.     

Pancreatic cystic lesions of difficult diagnosis

Cystic lesions of the pancreas include pseudocysts (90%), cystic tumors and true cysts. Preoperative diagnosis will guide the therapeutic strategy. Certain malignant or potentially malignant cysts (mucinous cystadenomas and cystadenocarcinomas) should be removed surgically while others (pseudocysts and serous cystadenomas) are almost always benign. In 3 out of 4 cases, the clinical setting guides diagnosis and with adequate imaging (sonography, computed tomography, endosonography) the correct diagnosis can be obtained. Inversely, the nature of a unique macrocyst it is often difficult to identify. Puncture is useful to determine tumor markers which are sometimes helpful in complementing information provided by imaging techniques.     

Duodenal tuberculosis: a difficult diagnosis

BACKGROUND: The polymorphous clinical presentation of tuberculosis located in the duodenum may mislead diagnosis. CASE REPORT: A 69-year-old man had duodenal stenosis associated with calculous common bile duct obstruction. Crohn's disease was initially diagnosed and the patient was treated with corticosteroids. Two months later, the diagnosis was rectified when pulmonary tuberculosis developed. DISCUSSION: This case emphasizes the lack of specific clinical, radiological, endoscopic and histological signs of duodenal tuberculosis.     

Diprivan: sedation for difficult intubation

No study has compared anaesthetic protocols appropriate for the sedation for fiberoptic tracheal intubation. Extrapolation of results of randomised studies comparing sedation techniques for diagnostic bronchoscopy under local anaesthesia enables the following conclusions: 1. Possible hypnotic agents for this procedure are benzodiazepines, barbiturates and propofol. Fentanyl improves the conditions for bronchoscopy. 2. Sedation using propofol is a well established technique. The induction dose, given as a bolus injection is 1 mg.kg-1, followed by continuous maintenance infusion of 1 mg.kg.h-1. 3. Irrespective of the sedation protocol used, there is always respiratory depression which justifies the need for preoxygenation, continuous oxygenation and Spo2 monitoring. Reversal of benzodiazepine and opioid effects may temporarily protect against respiratory depression.     

Predicting difficult intubation--a comprehensive scoring system

PURPOSE: To measure the pH in the precorneal tear film of humans in vivo using a pH-sensitive fluorescent dye, bis-carboxyethyl-carboxyfluorescein (BCECF). METHODS: The measurement was initiated by instilling 1 microliter of 2 mM BCECF solution into the subject's eye. The pH was calculated by measuring the ratio of fluorescent intensities at two excitation wavelengths (490/430 ratio), which was dependent on pH, but independent of the dye concentration and other variables. The tears of the same subject were then collected and loaded on to a micro pH-meter to ensure the accuracy of the measurement. RESULTS: The mean pH values of 40 eyes from 20 healthy volunteers was 7.50 (SD +/- 0.23), which corresponded well with those measured by the micro pH-meter. CONCLUSIONS: The method described was useful in measuring the pH of the precorneal tear film of humans with minimal invasion.     

Colonoscopy--how difficult, how painful?

Colonoscopy is sometimes painful for the patient and often difficult for the endoscopist, but it is hard to predict how difficult or painful the examination will be. The purpose of this study was to identify factors that influence difficulty and pain during colonoscopy. Some 1,284 consecutive patients undergoing office colonoscopy by three endoscopists were prospectively studied. A standard questionnaire was completed by the nursing staff, who assessed the degree of difficulty and pain associated with each exam on a four-point scale. There were 682 men and 551 women (sex not recorded in 51). There was no pain in 27%, mild pain in 39%, moderate pain in 25%, and severe pain in 9%. There was no difficulty in 25%, mild difficulty in 33%, moderate difficulty in 28%, and severe difficulty in 14%. Colonoscopy was significantly easier (P < 0.001, chi square) and less painful (P < 0.001, chi square) in patients after sigmoidectomy. It was more painful after hysterectomy (P < 0.05, chi square) and more difficult and painful in women than in men (P < 0.01, chi square). There were significant differences between endoscopists in the assessment of pain associated with colonoscopy. Most colonoscopies are associated with little or no pain (66%) and are easy or only mildly difficult to perform (58%). Patients who have had sigmoid resection are especially easy and painless to examine while women, especially after hysterectomy, are at higher risk of having a painful experience. Colonoscopy technique can influence the amount of pain experienced by the patient.