[Management of the difficult airway : Overview of the current guidelines]. / Management des schwierigen Atemwegs : Übersicht über die aktuellen Leitlinien.

Several national airway task forces have recently updated their recommendations for the management of the difficult airway in adults. Routinely responding to airway difficulties with an algorithm-based strategy is consistently supported. The focus is increasingly not on tools and devices but more on good planning, preparation and communication. In the case of anticipated airway difficulties the airway should be secured when the patient is awake with maintenance of spontaneous ventilation. Unaltered a flexible bronchoscopic intubation technique is advised as a standard of care in such patients. The importance of maintenance of oxygenation is emphasized. Face mask ventilation and the use of supraglottic devices are recommended if unexpected airway difficulties occur. Face mask ventilation may be facilitated and optimised by early administration of neuromuscular blocking agents. If required, in not fastened patients threatened by acute hypoxia, carefully applied and pressure-controlled ventilation may ensure sufficient oxygenation until the airway is secured. Apnoeic oxygen techniques are recommended in high-risk patients and to relieve the time pressure of falling oxygen saturation during decision-making processes. The early use of video laryngoscopy is advised for endotracheal intubation in the case of failed direct laryngoscopy or if intubation is expected to be difficult. For the coverage of cannot intubate-cannot oxygenate scenarios, second generation supraglottic devices and invasive airway access are advocated. The discussion regarding the optimal technique for emergency invasive airway access is still in progress. In the case of uncontrollable respiratory deterioration and progressive hypoxia, the algorithm must be consistently executed and without delay due to ineffective activities (straightforward strategy). Although there is no evidence to support the selection of a particular approach, the importance and the need for a defined airway concept/algorithm in any anesthesia department is fostered. Simplicity and clarity are essential for recall under stressful and time-sensitive conditions. The algorithm should be adapted to local conditions and preferences and devices should be limited to a definite number. The acquisition and maintenance of expertise by education and training is demanded.

Ensuring safety of patients receiving sedation for procedures: evaluation of clinical practice guidelines.

BACKGROUND: In 1995 The Johns Hopkins Hospital in Baltimore convened an interdisciplinary task force to evaluate sedation practices, create a comprehensive set of sedation guidelines, and evaluate patient safety outcomes following guideline implementation. METHODOLOGY: Baseline data were collected on all procedures in which sedation was administered by a nonanesthesiologist for a 6-month period, using scanning technology to automate data entry. Sedation practices were reviewed, and four critical events were examined: unresponsiveness, obstructed airway, airway placement, and cardiopulmonary resuscitation (CPR). In 1998 data collection procedures were repeated to evaluate the impact of the guidelines on sedation practices and patient safety outcomes. RESULTS: In 1995 sedation practices varied, and one or more critical events occurred in 45 (1.4%) of 3,255 procedures. Steps taken included development and dissemination of a clinical sedation guideline, including monitoring criteria to guide nonanesthesiologists, and evaluation planning. In 1998 sedation practices were more consistent. One or more critical events occurred in 50 (1.6%) of 3,134 procedures, representing a small increase in critical events from 1995. More events of unresponsiveness were identified, and no event required CPR. Although not statistically significant, this trend suggests that critical events were being identified earlier, preventing patients from progressing to a more serious event requiring CPR. Steps taken included further refinement of clinical practice guidelines and establishment of ongoing monitoring. CONCLUSIONS: Standardization of sedation practices is a complex and resource-intensive activity, requiring ongoing oversight and monitoring. Commitment from medical staff, nursing staff, and administration is essential to successful implementation of sedation guidelines.

Prevalence of latex allergy among anesthesiologists: identification of sensitized but asymptomatic individuals.

BACKGROUND: Occupational exposure to natural rubber latex has led to sensitization of health-care workers. However, the prevalence of latex allergy among occupationally exposed workers in American hospitals has not been reproducibly determined. The objectives of the current study were to determine the prevalence of and risk factors for latex sensitization among a cohort of highly exposed health-care workers. METHODS: Participants were 168 of 171 eligible anesthesiologists and nurse anesthetists working in the Department of Anesthesiology and Critical Care Medicine. A clinical questionnaire was administered, and testing was performed using a characterized nonammoniated latex reagent for puncture skin testing, a Food and Drug Administration-approved assay to quantify latex-specific immunoglobulin E antibody in serum, and, when required for clarification, a validated two-stage (contact-inhalation) latex glove provocation procedure. RESULTS: The prevalence of latex allergy with clinical symptoms and latex sensitization without clinical symptoms was 2.4% and 10.1%, respectively. The prevalence of irritant or contact dermatitis was 24%. The risk factors identified for latex sensitization were atopy (odds ratio, 14.1; 95% CI, 1.8-112.1; P = 0.012); history of allergy to selected fruits, such as bananas, avocados, or kiwis (odds ratio, 9.8; 95% CI, 1.6-61.9; P = 0.015); and history of skin symptoms with latex glove use (odds ratio, 4.6; 95% CI, 1.6-13.4; P = 0.006). CONCLUSIONS: The prevalence of latex sensitization among anesthesiologists is high (12.5%). Of these, 10.1% had occult (asymptomatic) latex allergy. Hospital employees may be sensitized to latex even in the absence of perceived latex allergy symptoms. These data support the need to transform the health-care environment into a latex-safe one that minimizes latex exposure to patients and hospital staff.

Scanner technology for data-based decision making.

Scanner systems offer several benefits to nurse executives. Clinical, educational, and administrative data can guide the nurse executive's decisions providing greater control over patient care outcomes. Information from large patient care data sets provides a powerful tool for persuading executives in other departments. Additionally, the nurse executive who can eliminate the need for personnel to conduct time consuming and costly manual data entry, may be able to justify financial support for continued development of the nursing department's information system and technological training for the staff. In this way, scanner technology meets the immediate need for information and serves as an entry to more advanced communications systems.

The difficult airway: mechanisms for effective dissemination of critical information.

The perioperative management and dissemination of critical information regarding a patient with an unexpected difficult intubation, including successful application of a difficult airway algorithm (Figure 1), are described. Documentation and dissemination of critical information include entry of patient data into an in-hospital computerized Difficult Airway/Intubation Registry, simultaneous application of a highly visible Difficult Airway/Intubation Patient Wrist Band (coded for access to computer registry), summary reports distributed to health care providers, and enrollment of the patient in the Medic Alert Foundation International's newly established category difficult airway/intubation for 24-hour access. We postulate that the widespread use of the procedures described in this report may reduce the contribution of unexpected difficult airway/intubation to anesthetic morbidity and mortality.

Aortic disease associated with pregnancy.

Our experience with the management of two patients with life-threatening aortic disease during pregnancy is presented with a review of the literature. One of our patients had intimal disruption caused by trauma; the other had probable Ehlers-Danlos type IV syndrome, causing an acute dissection of the descending thoracic aorta and eventually requiring replacement of the aorta from the left subclavian artery to common iliac arteries. The challenge of treating both the pregnant woman and the fetus was managed successfully by an emergent cesarean section followed by Dacron graft replacement of the descending thoracic aorta. The literature reviewed disclosed that aneurysm expansion producing symptoms and dissection is most common during the third trimester and during labor and delivery in patients with or without Marfan's syndrome. Half of the aortic dissections in women less than 40 years of age occur in association with pregnancy. The available evidence indicates that patients with known valvular or aortic disease should have surgical repairs during the first or second trimester and thereafter have delivery by cesarean section. However, patients with acute aortic problems near term appear to be better managed by cesarean section followed promptly by treatment of the aortic disease.

Limitations of thermodilution ejection fraction: degradation of frequency response by catheter mounting of fast-response thermistors.

The present study examined whether catheter-mounting of a fast-response thermistor impaired the thermistor's ability to measure rapid temperature changes during thermodilution measurement of ejection fraction (EF). The response to a square-wave temperature change of six fast-response thermistors mounted on commercially available, pulmonary artery balloon-flotation catheters was compared to the response of a similar but unmounted fast-response thermistor. The response of the catheter-mounted fast-response thermistors recorded only 82% to 92% of a step-temperature change at 0.5 sec, and 88% to 96% of the step change at 1.0 sec. In contrast, the unmounted fast-response thermistor responded to 100% of the step change in 125 msec. The response of the catheter-mounted fast-response thermistors demonstrated an important slow component (second time constant) introduced by the catheter body, so that equilibration to a temperature change was not complete for about 6 sec. This slow equilibration lowered EF measured by thermodilution below true EF.

Overestimation of pediatric cardiac output by thermal indicator loss.

The accurate measurement of pediatric cardiac output by thermodilution requires that the quantity of cold indicator introduced into the central circulation be known. This study defines an important source of error in the correction factor for the amount of heat gained by small volumes of cold injectate during passage through pediatric catheter systems. This error may result in significant overestimation of cardiac output (as much as 59%) when blood at body temperature is withdrawn into the injection lumen of the pediatric catheter before the injection.

Planetary radio astronomy observations from voyager 1 near saturn.

The Voyager 1 planetary radio astronomy experiment detected two distinct kinds of radio emissions from Saturn. The first, Saturn kilometric radiation, is strongly polarized, bursty, tightly correlated with Saturn's rotation, and exhibits complex dynamic spectral features somewhat reminiscent of those in Jupiter's radio emission. It appears in radio frequencies below about 1.2 megahertz. The second kind of radio emission, Saturn electrostatic discharge, is unpolarized, extremely impulsive, loosely correlated with Saturn's rotation, and very broadband, appearing throughout the observing range of the experiment (20.4 kilohertz to 40.2 megahertz). Its sources appear to lie in the planetary rings.

Left ventricular function during aortic surgery.

Fourteen patients undergoing surgery for aneurysm or occlusive disease of the abdominal aorta were studied. Thirteen patients had a history of hypertension or myocardial infarction; two patients had chronic obstructive pulmonary disease. Tachycardia, hypertension, and elevated pulmonary artery occluded. (PAo) pressure occurred in response to laryngoscopy and intubation in two patients; elevation of PAo pressure in response to aortic cross-clamping occurred in two patients. In three of these four patients, electrocardiographic evidence of myocardial ischemia appeared. These events are important in a consideration of the occurence of myocardial infarction in patients undergoing abdominal aortic surgery. Satisfactory treatment of myocardial ischemia has been accomplished with the use of propranolol hydrochloride and sodium nitroprusside.