The co-ordination of bimanual rapid aiming movements following stroke.

OBJECTIVE: To determine the role of anticipatory and movement control processes for the coordination of bimanual target aiming in individuals post stroke. SUBJECTS: Thirty adults with chronic stroke and 30 individuals without stroke history. DESIGN: A two-group (stroke, control) by two-aiming type (unimanual, bimanual) by two-limb (paretic, nonparetic; left, right for controls) design with repeated measures on the last two factors. OUTCOME MEASURES: Kinematic analyses of performance and psychometric measures of reaction time, movement time, peak resultant velocity, time to and after peak resultant velocity and interlimb timing for movement initiation and target impact. RESULTS: Compared with unimanual aiming, the nonparetic limb exhibited a prolonged movement time in the bimanual condition; the locus for prolongation was primarily in the deceleration phase. This adaptive response allowed for a nearly simultaneous (both limbs) target impact in 81% of trials. Compared with the unimanual condition, the nonparetic limb exhibited a lower peak velocity (10%) in the bimanual condition. Conversely, compared with the unimanual condition, the paretic limb exhibited a higher peak velocity (4%) in the bimanual condition. This disociation between limb and condition was observed for the stroke group but not the control group. CONCLUSIONS: The interlimb coordination that emerged for the stroke group revealed a complex and asymmetric contribution from each limb mediated through anticipatory and motor control processes. We suggest that this coordination may be harnessed for future bimanual intervention approaches to rehabilitation of upper limb function after stroke.

The airway: problems and predictions in 18,500 patients.

The purpose of this study was to describe methods, risk factors, and outcomes of airway management in all patients (obstetrics excluded) attended by anaesthetists over 27 months. Preoperatively, anaesthetists recorded patient factors and assessed four airway characteristics. Methods of tracheal intubation and ease of direct laryngoscopy following general anaesthesia (easy, awkward, difficult) were noted. Factors predictive of poor outcome and the value of the preoperative airway examination were determined. For 18,205 patients following a direct laryngoscopy, (GA), tracheal intubation was difficult (> 2 laryngoscopies) in 1.8% and awkward (< or = 2 laryngoscopies) in 2.5%. This approach was a failure in 0.3%, and surgery was postponed in 0.05%. However, an alternative approach to direct laryngoscopy, (GA) was the first choice in 353 patients. Risk factors for difficult tracheal intubation included male sex, age 40-59 yr and obesity (P < or = 0.01). For direct laryngoscopy, (GA), airway characteristics predictive of difficult tracheal intubation were decreased mouth opening (relative risk 10.3), shortened thyromental distance (9.7), poor visualization of the hypopharynx (4.5), and limited neck extension (3.2), any two (7.6) and more than two (9.4) (P < 0.01). For 1,856 patients (10.0%) where at least one airway characteristic was abnormal, a direct laryngoscopy, (GA) resulted in 8.3% awkward and 6.0% difficult tracheal intubations. For patients with no abnormal airway characteristics, tracheal intubation was easy in 96.3%. Where tracheal intubation was difficult, 34.3% of patients had one or more abnormal airway characteristics preoperatively. Patients with difficult tracheal intubation had an increased rate of desaturation (< 90%), hypertension (> 200 mm Hg) and dental damage on induction of anaesthesia. It is concluded that difficult tracheal intubations occurred infrequently but were associated with increased morbidity. Patient factors and four physical airway characteristics were useful predictors but limited in identifying all problems.

Pathophysiology and prevention of acute renal failure: the role of the anaesthetist.

Ischaemic renal tubular damage in the perioperative period can lead to acute renal failure (ARF) with a very high mortality rate (60-75 per cent). Recent research suggests that this tubular injury is caused by an imbalance of the oxygen supply and demand of medullary thick ascending limb (mTAL) tubular cells. High oxygen demand is secondary to active reabsorption of solute which is increased in states of intravascular volume depletion. The restricted supply of oxygen is secondary to the organization of blood flow to the inner medulla. Because the vasa recta loop into the inner medulla and a countercurrent exchange process for oxygen is established, the oxygen tension in this area may normally be as low as 10-20 mmHg. In hypoperfusion states, mTAL injury occurs and is exacerbated by intravascular volume depletion, hypoxaemia and endothelial cell swelling which reduces perfusion of these vulnerable and metabolically active mTAL cells. The anaesthetist must prevent or attenuate postoperative renal dysfunction by identifying high-risk patients preoperatively, optimizing intravascular volume status and cardiac output in the perioperative period, as well as responding appropriately to hypoperfusion states. Therapeutic implications relate to this pathophysiological sequence and several physiological and pharmacological considerations are discussed.

The intubating laryngeal mask airway with and without fiberoptic guidance.

UNLABELLED: We conducted this feasibility study using the intubating laryngeal mask airway (ILMA) and a polyvinyl chloride tracheal tube to compare success rates, hemodynamic effects, and postoperative morbidity with two methods of tracheal intubation. After ethics approval and informed consent, 90 healthy ASA physical status I or II women with normal airways were enrolled in the randomized, controlled study. After a standardized inhaled anesthesia induction protocol, tracheal intubations using ILMA with fiberoptic guidance (ILMA-FOB) and ILMA inserted blindly without fiberoptic guidance (ILMA-Blind) were compared with the control group of direct laryngoscopy (laryngoscopy group). All 90 patients were successfully ventilated. For tracheal intubation, success rates were equal in all three groups (97%). Total intubation times were longer for the ILMA-FOB group (77 s versus 48.5 s for laryngoscopy and 53.5 s for ILMA-Blind). The laryngoscopy group had a larger increase in mean arterial blood pressure to tracheal intubation. There were no differences in postoperative sore throat or hoarseness among the groups. In conclusion, success rates are equally high for tracheal intubation using ILMA-Blind and ILMA-FOB techniques in women with normal airways. IMPLICATIONS: The intubating laryngeal mask airway (ILMA) can be used as a primary airway for oxygenation and ventilation. Both methods of tracheal intubation using the ILMA were equally successful. Postoperative morbidity in the ILMA groups was similar to that in the laryngoscopy group. For women with normal airways, both the ILMA inserted blindly and the ILMA with fiberoptic guidance are suitable alternatives to laryngoscopy for tracheal intubation.

The incidence of airway problems depends on the definition used.

PURPOSE: Definitions currently used to describe airway difficulties are confusing, inconsistent, and may be misleading. To understand the "extent of the problem" better using three different definitions we examined the corresponding rates of airway difficulty in 3,325 consecutive adult patients who had direct laryngoscopy with tracheal intubation following induction of general anaesthesia. METHODS: Definitions were (i) poor view at laryngoscopy (GRADE 3-4) documented on modified diagrams of Cormack and Lehane; (ii) > or = 3 laryngoscopy attempts; and (iii) failure of direct laryngoscopy. The incidences of airway difficulty attributable to each definition were compared. RESULTS: For the three definitions rates varied, 10.1% for poor view, 1.9% > or = 3 laryngoscopies, and failure 0.1%. For patients with a GRADE 3-4 view, 15.8% required > or = 3 laryngoscopies, but for those with > or = 3 laryngoscopies, 84.1% had GRADE 3-4 view. All patients with failed laryngoscopy had > or = 3 laryngoscopies and a GRADE 4 view. CONCLUSION: This wide variation in defining the "extent of the problem" emphasizes the need for agreement of definitions and improved methods to document airway difficulties.

Laparoscopic cholecystectomy: the anaesthetist's point of view.

Although the surgical advantages of laparoscopic cholecystectomy (LC) have been reported, the anaesthetic problems associated with this new technique have not been well described. For the first 101 patients undergoing laparoscopic cholecystectomy at our institution, we prospectively documented intraoperative critical observations and adverse outcomes in the PACU (Post-Anaesthetic Care Unit). In order to put the magnitude of these problems into perspective, we compared, in an identical manner, the anaesthetic management and outcomes of two more familiar surgical groups, cholecystectomy by laparotomy (C), and laparoscopy for gynaecological examination (LG). For this new procedure LC, intraoperative hypotension (12.9%), and PACU hypothermia (31.4%), nausea and vomiting (12.9%) and desaturation (10.9%) were common but excessive pain (4.0%) was rare. Patients undergoing C, who were older and less healthy, tended to have fewer incidents of OR hypotension (3.4%) but in the PACU experienced more desaturation (25.9%) and excessive pain (12.9%) (P < or = 0.05). The younger and healthier LG group had fewer problems, less OR hypotension (0.4%), and less PACU nausea and vomiting (5.7%) and desaturation (1.3%) (P < or = 0.05). However, the LG group had a similar incidence of excessive pain (4.4%). We have documented considerable postoperative anaesthetic benefits for patients undergoing laparoscopic cholecystectomy compared with conventional cholecystectomy. However, there is still considerable perioperative morbidity compared with gynaecological laparoscopies. Now that specific problems have been identified, they may be amenable to specific anaesthetic interventions.

Management of a malignant hyperthermia patient during cardiopulmonary bypass.

The anaesthetic management of cardiopulmonary bypass (CPB) for a patient with biopsy-proven malignant hyperthermia is reported. Specific changes in the technique used, such as venting the oxygenator before use, monitoring mixed venous PO2 and PCO2, as well as the safety of cold hyperkalaemic cardioplegia are described. Controversial aspects of malignant hyperthermia management such as the safety of calcium and catechol inotropes are discussed in relationship to the successful use of cardio-pulmonary bypass in our patient. We chose to treat left ventricular dysfunction by aggressive vasodilator (nitroglycerine) therapy. We detected no myocardial or respiratory depression secondary to dantrolene therapy either before or after operation.

Changing the practice of pain management.

Since postoperative pain is associated with morbidity and increased hospital resources, reducing pain should improve patient care. Enhanced education and individualized feedback were introduced at the study hospital to promote anesthesiologists' use of patient-controlled analgesia, nonsteroidal antiinflammatory drugs, epidural morphine, and nerve blocks. After 6-mo baseline, anesthesiologists at the study hospital attended educational seminars and received literature about pain management. Personalized feedback forms were then distributed to each anesthesiologist showing the management and rates of pain for their patients. Practice was as usual at a control hospital. Pain in the postanesthesia care unit (PACU) and for 6-h post-PACU discharge was assessed using PACU records and interviews for 3413 patients at the study hospital and 1753 at the control hospital. From the baseline to the feedback period, the absolute increase in the proportion of patients receiving at least one promoted strategy was greater at the study hospital than at the control hospital (44.9% vs 22.8% P < 0.0001). Mean pain scores with activity decreased at both hospitals; study hospital 7.6 (7.3-7.8, 99% confidence interval) to 6.2 (5.9-6.5); control hospital 7.3 (6.9-7.6) to 6.1 (5.7-6.4). Education and feedback increased the use of pain management strategies at the study hospital. The modest change in patient outcome was unlikely related to directed interventions.

Changing anesthesiologists' practice patterns. Can it be done?

BACKGROUND: Because the ultimate purpose of new medical knowledge is to achieve improved health outcomes, physicians need to possess and use this knowledge in their practice. The authors introduced enhanced education and individualized feedback to reduce postoperative nausea and vomiting (PONV). The primary objective was to increase anesthesiologists' use of preventive measures to reduce PONV, and the secondary objective was to determine whether patient outcomes were improved. METHODS: After obtaining hospital ethics committee approval, the effect of education and feedback on anesthesiologist performance and the rate of PONV in major surgery elective inpatients during a 2-yr period was assessed. After baseline data collection (6 months), anesthesiologists at the study hospital received enhanced education (8 months) and individualized feedback (10 months). Parallel data collection was performed at a control hospital at which practice was continued as usual. The education promoted preventive measures (antiemetic premedication, nasogastric tubes, droperidol, metoclopramide). Individualized feedback provided the number of patients receiving promoted measures and the rate of PONV. The mean percentage of anesthesiologists' patients receiving at least one promoted measure and the rate of PONV were compared with baseline levels. RESULTS: At the study hospital, there was a significant increase in the mean percentage of the anesthesiologists' female patients receiving a preventive measure as well as a significant increase in the use of droperidol > or = 1 mg (P < 0.05) for all patients. The use of other promoted measures was unaffected. Absolute rates of PONV were unaffected at the study hospital until the post-feedback period (decrease of 8.8% between baseline and post-feedback (P = 0.015)). CONCLUSION: It was demonstrated that enhanced education and individualized feedback can change anesthesiologists' practice patterns. The actual benefit to patients from use of preventive measures was limited when used in the everyday clinical situation. Therefore, only modest decreases in PONV were achieved, despite the use of preventive measures.

Cardiovascular events in the postanesthesia care unit: contribution of risk factors.

BACKGROUND: The purpose of this study was to determine the relationship of four postanesthesia care unit (PACU) cardiovascular events to long-term outcomes (unplanned critical care admission or mortality) and to evaluate the contribution of anesthetic management compared with other perioperative factors in predicting these events. METHODS: For patients admitted to the PACU after receiving general anesthesia (n = 18,380), the risk of long-term outcomes was examined for patients in the PACU with hypertension, tachycardia, bradycardia, or hypotension. Using logistic regression (P < 0.05), risk factors (grouped as patients, surgical, anesthetic, operating room observations, and other PACU observations) for each cardiovascular event were determined. For each factor grouping, the relative contributions to each cardiovascular event were compared using maximum likelihood chi-square analysis. RESULTS: Patients in the PACU with hypertension or tachycardia had more unplanned critical care admissions (2.6% and 4.0% vs. 0.2% for patients with no events) and greater mortality (1.9% and 2.3% vs. 0.3% and 0.4%) (P < 0.01). For PACU hypertension (rate 2.0%), age, smoking, renal disease, female gender, and angina were significant risk factors. For PACU tachycardia (0.9%), intraoperative tachycardia and dysrhythmia were the major contributors. Patient factors also increased the risk of bradycardia (2.5%); namely age, ASA physical status 1 or 2, and preoperative beta blocker therapy. For hypotension (2.2%), duration of surgery > 2 h, completion after 6 PM, and gynecologic intraabdominal procedures were significant risk factors. Compared to patient, surgical, intraoperative, or PACU observations, anesthetic factors studied (premedication, induction agent, ventilation, use of opioids) provided only a small contribution in predicting these events. CONCLUSIONS: Hypertension and tachycardia in the PACU, although infrequent, are associated with increased risk of unplanned critical care admission and mortality. Patient, surgical, intraoperative, or PACU observations contribute more to cardiovascular events in the PACU than do differences in anesthetic management identified in this study.

Critical respiratory events in the postanesthesia care unit. Patient, surgical, and anesthetic factors.

BACKGROUND: Previous studies have noted a high incidence of adverse outcomes in the postanesthesia care unit (PACU), but few have examined associated factors and patient outcomes. To determine the frequency of acute, unanticipated respiratory problems and to examine the associated patient, surgical, and anesthetic factors, we prospectively collected preoperative, intraoperative, and postoperative data on 24,157 consecutive PACU patients who received a general anesthetic during a 33-month period. METHODS: A PACU critical respiratory event (CRE), was defined as any unanticipated hypoxemia (hemoglobin oxygen saturation < 90%), hypoventilation (respiratory rate < 8 breaths/min or arterial carbon dioxide tension > 50 mmHg) or upper-airway obstruction (stridor or laryngospasm) requiring an active and specific intervention (ventilation, tracheal intubation, opioid or muscle relaxant antagonism, insertion of oral/nasal airway or airway manipulation). These problems were documented by PACU nurses whereas data on case-mix, surgical factors, and intraoperative management were retrieved from the anesthetic record. Significant patient, surgical, and anesthetic factors were identified by logistic regression analysis. Other morbidity experienced by patients with a CRE was also noted. RESULTS: For patients given general anesthesia the risk of a CRE was 1.3% (hypoxemia 0.9%, hypoventilation 0.2%, airway obstruction 0.2%). Preoperative factors that increase risk were age > 60 yr, male gender, diabetes, and obesity (P < 0.05). Patients who underwent operative procedures on an emergency basis and whose operation was longer than 4 h were also at increased risk, but those undergoing perineal procedures were at lower risk (P < 0.05). Anesthetic risk factors (P < 0.05) included opioid premedication (relative odds 1.8), sedatives preoperatively (2.0), fentanyl > 2.0 micrograms.kg-1.h-1 as the sole opioid (1.9), fentanyl used in combination with morphine (1.6) and atracurium > or = 0.25 mg.kg-1.h-1 (2.2). Patients in whom anesthesia was induced with thiopental (relative odds 2.5), compared with those who received propofol for induction, were also at increased risk of a CRE. Patients with a CRE stayed longer in PACU, had higher rates of unanticipated admissions to the intensive care unit and were more likely to have PACU cardiac problems (P < 0.01). CONCLUSIONS: A CRE is relatively rare. Multiple patient and surgical factors and specific aspects of anesthetic management are associated with the occurrence of a CRE in the PACU.

Development of a computerized database for the study of anaesthesia care.

To record, tabulate and report problems associated with anaesthesia, we have developed an information collection system and computer software to follow all patients attended by an anaesthetist at a teaching hospital in Canada. For the last 15 mo, data for 17,000 patients have been collected and the system is ongoing. Data collection is from three sources: carbonless copies of the handwritten Operating Room (OR) and Post Anaesthetic Care Unit (PACU) records, other hospital databases, and postoperative visits. Adverse events (observations which differ from specific physiological variables, or require an intervention and do not normally occur during the routine conduct of anaesthesia), are defined directly on each OR and PACU record. These events are recorded when they occur by the attending anaesthetist or the PACU nurse. All data are verified by a research nurse and an anaesthetist. Computer software, developed from DBase IV, is used to track 95 individual items on preoperative status and anaesthetic technique and another possible 1,450 selections for drugs, physicians, airways, surgical procedures and events for each patient. Data are analyzed with SAS software and reports generated to link the casemix and process with outcome. Comparison of data entered into the computer programme to a retrospective chart review revealed discrepancies of less than 0.5%. Collection, verification and computer entry takes five minutes per patient and the on-going cost is estimated at $4 per patient record. Analysis of the information collected in this database has been useful for research of adverse outcome following anaesthesia, resident expertise profiles, and the administrative management of an anaesthesia department.

The intubating laryngeal mask airway after induction of general anesthesia versus awake fiberoptic intubation in patients with difficult airways.

UNLABELLED: We performed the current study to compare tracheal intubation (TI) using awake fiberoptic intubation (AFOI) and TI using the intubating laryngeal mask airway (ILMA) in patients with difficult airway. Our hypothesis was that patients with difficult airways could be safely intubated after induction of anesthesia using the ILMA. After ethics approval and informed consent, 38 patients who were identified to have difficult airways were randomly assigned to AFOI or TI using the ILMA. Patients in the AFOI group had the usual sedation and airway topicalization. Patients in the ILMA group were induced with propofol for ILMA insertion and succinylcholine for TI. The first TI attempt was done blindly via the ILMA and all subsequent attempts were performed with fiberoptic guidance. All patients in the ILMA group were successfully ventilated. Successful TI was achieved in all patients in both groups. However, in 10% of the patients in the ILMA group, TI was achieved by a second anesthesiologist who was more experienced with the use of the ILMA. In a postoperative questionnaire, patients in the ILMA group were more satisfied with their method of TI (P < 0.01). The ILMA is a useful device in the management of patients with difficult airways and may be a valuable alternative to AFOI when AFOI is contraindicated or in the patient with the unanticipated difficult airway. IMPLICATIONS: The intubating laryngeal mask airway is a useful device in the management of patients with difficult airways and may be a valuable alternative to awake fiberoptic intubation (AFOI) when AFOI is contraindicated or in the patient with the unanticipated difficult airway.

Predicting difficult intubation: a multivariable analysis.

PURPOSE: To develop a clinically useful and valid model for predicting difficult laryngoscopic tracheal intubation in patients with seemingly normal airways by adhering to the principles of multivariable model development. METHODS: This was an observational study performed at a tertiary-care teaching hospital. Preoperatively, 444 randomly selected patients requiring tracheal intubation for elective surgery were assessed. In addition, 27 patients in whom tracheal intubation was difficult, but were not assessed preoperatively, were assessed postoperatively. One assessor, blinded to the intubation information, collected the predictor variables. A reliable definition for difficult intubation was used and all attempts were made to eliminate sources of bias. Multivariable modeling was performed using logistic regression and the model was validated using the bootstrapping technique. RESULTS: Of the 461 patients included in the analysis, 38 were classified as difficult to intubate. Multivariable analysis identified three airway tests that were highly significant for predicting difficult tracheal intubation. These were: 1) "mouth opening", 2) "chin protrusion", and 3) "atlanto-occipital extension". Using these tests, a validated, highly reliable and predictive model is produced to determine the probability of difficult intubation for patients. At a selected probability cut-off value, the model is 86.8% sensitive and 96.0% specific. CONCLUSION: A simple and accurate multivariable model, consisting of three airway tests, is produced for predicting difficult laryngoscopic tracheal intubation. Additional studies will be required to determine the accuracy and feasibility of this model when applied to a large sample of new patients by multiple anesthesiologists.

Planned and unplanned postoperative admissions to critical care for mechanical ventilation.

PURPOSE: To determine which factors influence the clinician in choosing critical care admission and postoperative ventilation, we prospectively examined the incidence, timing, causes, and risk factors for admission to critical care for postoperative ventilation within 48 hr of a surgical procedure (excluding cardiac and neurosurgical). METHODS: Patients were categorized as: admission planned preoperatively; admission unplanned and identified in the OR (Operating Room) or PACU (Post Anaesthetic Care Unit); and admission unplanned, identified after PACU discharge. Rates of admission by category for those with specific preoperative and intraoperative characteristics were compared to those without the characteristics to determine risk factors for admission (P < 0.01). RESULTS: Only 329 of 15,059 cases (2.2%) had a critical care admission. Of these, 288 were planned, 31 identified in the OR or PACU, and 10 after PACU discharge. A respiratory aetiology was the reason for admission in 75% of unplanned cases. Preoperatively, age > or = 60 yr and common systemic illnesses (cardiac, renal, pulmonary) were markers for planned admission, but only positive HIV status was a risk factor for unplanned admission. The two main physiological features which identified all critical care admissions were haemoglobin oxygen saturation < 90% (preoperatively breathing room air and intraoperatively) and tachycardia during the operative period. Six of ten of the unplanned after PACU discharge patients underwent bronchoscopy with a neurolept analgesic technique. CONCLUSION: Postoperative admissions to a critical care unit, both planned and unplanned, are uncommon. This study has identified haemoglobin oxygen desaturation during the perioperative period and intraoperative tachycardia as important markers for all admissions to critical care.

Nursing workload associated with adverse events in the postanesthesia care unit.

BACKGROUND: The authors used a nursing task inventory system to assess nursing resources for patients with and without adverse postoperative events in the postanesthesia care unit (PACU). METHODS: Over 3 months, 2,031 patients were observed, and each task/activity related to direct patient care was recorded and assigned points according to the Project Research in Nursing (PRN) workload system. PRN values for each patient were merged with data from an anesthesia database containing demographics, anesthesia technique, and postoperative adverse events. Mean and median PRN points were determined by age, sex, duration of procedure, and mode of anesthesia for patients with and without adverse events in the PACU. Three theoretical models were developed to determine the effect of differing rates of adverse events on the requirements for nurses in the PACU. RESULTS: The median workload (PRN points) per patient was 31.0 (25th-75th percentile, 25-46). Median workload was 26 points for patients with no postoperative events and 155 for > or = six adverse events. Workload varied by type of postoperative event (e.g., unanticipated admission to the intensive care unit, median workload = 95; critical respiratory event = 54; and nausea/vomiting = 33). Monitored anesthesia care or general anesthesia with spontaneous ventilation used less resources compared with general anesthesia with mechanical ventilation. Modeling various scenarios (controlling for types of patients) showed that adverse events increased the number of nursing personnel required in the PACU. CONCLUSIONS: Nursing care documentation based on requirements for individual patients demonstrates that the rate of postoperative adverse events affects the amount of nursing resources needed in the PACU.

Influence of mannitol and dopamine on renal function during elective infrarenal aortic clamping in man.

The impact of elective infrarenal aortic clamping on parameters of renal function was evaluated in 27 extracellular fluid volume expanded patients. Significant transient decreases (p less than 0.05) in glomerular filtration rate were observed in all three groups either in the early or late post-clamp release period, despite maintenance of hemodynamic stability. This study documents transient decreases in glomerular filtration rate which occurred following release of the infrarenal aortic cross-clamp. No clinically important benefit from the use of mannitol and dopamine over extracellular fluid volume expansion with saline alone was demonstrated in the prevention of the changes in renal function associated with aortic cross-clamping.

Inter-observer reliability of ten tests used for predicting difficult tracheal intubation.

PURPOSE: To determine inter-observer reliability of ten preoperative airway assessment tests used for predicting difficult tracheal intubation. METHOD: We prospectively assessed 59 patients undergoing elective surgery requiring tracheal intubation at a large metropolitan teaching hospital. Two experienced observers independently conducted the airway assessment tests on the same group of patients. Inter-observer reliability was examined using Kappa (K) and intraclass correlation coefficient (ICC). RESULTS: Two tests--mouth opening (ICC = 0.93) and chin protrusion (ICC = 0.89)--had excellent inter-observer reliability. Seven tests--thyromental distance (ICC - 0.74), subluxation (K = 0.66), atlanto-occipital extension distance (ICC = 0.67) and angle (K = 0.66), profile classification (K = 0.58), ramus length (ICC = 0.53), oropharyngeal best view (K = 0.49)--were moderately reliable. One test--Mallampati technique of assessing oropharyngeal view (K = 0.31)--had poor reliability. CONCLUSION: Many of the preoperative airway tests have only moderate inter-observer reliability. This may provide some insight into why previous research has failed to show that the tests accurately predict difficult tracheal intubation.

The relationship of postural sway to sensorimotor function, functional performance, and disability in the elderly.

OBJECTIVE: To examine the relationship of postural sway to sensorimotor impairment, functional performance, and self-reported disability. DESIGN: Cross-sectional cohort. SETTING: Department of Veterans' Affairs Medical Center. PATIENTS: One hundred community-dwelling elderly unable to climb stairs step over step. MAIN OUTCOME MEASURES: Postural sway (area of ellipse and path length, eyes open and closed), sensorimotor (strength, sensation, range of motion, central processing time), functional performance (functional reach, timed gait, mobility skills, endurance), and disability (MOS-SF36, Falls Efficacy Scale [FES]). RESULTS: Postural sway area measures correlated with sensorimotor measures: (1) During eyes-closed conditions, increased sway occurs in individuals with sensory deficits (p < .05); (2) Sway was positively correlated with tibialis anterior latency (p < .05); (3) Sway area measures increased with increased strength (p < .05). The sway/strength relationship may be explained by week subjects improving their stability by limiting rather than increasing sway. Sway was not significantly correlated with any measures of physical performance. Sway was correlated with some measures of disability: (1) Eyes-closed measures of postural sway were correlated with FES scores (p < .05); (2) Sway was not correlated with the MOS-36 physical functioning question. When controlling for functional measures, eyes-closed measures of sway significantly predicted FES scores (p < .03). CONCLUSIONS: Measures of postural sway are more likely capturing sensorimotor deficits rather than differentiating functional performance abilities, and the relationship between postural sway and self-reported disability is inconsistent.

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.