Improving fiberoptic intubation with a novel tongue retraction device.

This study examined the utility of a novel tongue retractor created with a wider working blade and a more ergonomic curve to provide jaw lift and tongue management with one hand during intubation. Anesthesia providers participated in simulated intubation of a difficult manikin using the novel tongue retractor with the Bonfils video fiberscope. Results show that the tongue retractor improved placement success and was well received by the study participants.

Improving rigid fiberoptic intubation: a comparison of the Bonfils Intubating Fiberscope with a novel modification.

BACKGROUND: The Bonfils intubating fiberscope has a limited upward tip angle of 40 degrees and requires retromolar entry into the hypopharynx. These factors may make its use less desirable when managing the difficult airway because most anesthesia providers are well versed in midline oral intubation rather than the lateral retromolar approach. The Center for Advanced Technology and Telemedicine at the University of Nebraska Medical Center has developed a novel fiberscope with a more anterior 60 degrees curve to allow for easier midline insertion and intubation. The objective of this work was to evaluate the novel fiberscope, in comparison to the Bonfils intubating fiberscope, in terms of use and function in difficult airway intubation. METHODS: Twenty-two anesthesia providers participated in simulated intubations of a difficult airway mannequin to compare the Bonfils intubating fiberscope with the novel curved Boedeker intubating fiberscope. The intubations were assessed based upon the following variables: recorded Cormack Lehane airway scores, requests for cricoid pressure, time to intubation, number of intubation attempts and success or failure of the procedure. RESULTS: Participants using the Bonfils fiberscope recorded an average Cormack Lehane (CL) airway score of 1.67 +/- 1.02 (median = 1); with the novel fiberscope, the recorded average airway grade improved to 1.18 +/- 0.50 (median = 1). The difference in airway scores was not statistically significant (p = 0.34; Fishers Exact Test comparing CL grades 1&2 vs. 3&4). There was, however, a statistically significant difference in intubation success rates between the two devices. With the Bonfils fiberscope, 68% (15/22) of participants were successful in intubation compared to a 100% success rate in intubation with the novel fiberscope (22/22) (p = 0.008). After the intubation trial, the majority of participants (95%) indicated a preference for the novel fiberscope (n = 20). CONCLUSIONS: With this data, we can infer that the novel fiberscope curvature appears to improve or maintain the quality of an intubation attempt (airway score, cricoid pressure requirement, intubation time, number of attempts, placement success). The data indicate that the novel fiberscope offers a superior intubation experience to currently available best practices. The instrument was well received and would be welcomed by most study participants should the device become clinically available in the future.

Team management training using crisis resource management results in perceived benefits by healthcare workers.

BACKGROUND: Systems failures and ineffective teamwork can lead to serious errors in practice. Crisis Resource Management (CRM) teaches leadership, effective communication skills, and improved team performance. The impact of CRM taught in a simulation laboratory was evaluated. METHODS: A mail survey was used to examine perceived benefits and application of CRM principles when encountering practice and everyday life crisis situations. All participants completing the course since its inception who could be located received the survey. RESULTS: Fifty-three of 149 participants (35%) responded to the survey. Eighty-three percent had managed a crisis since the course and 68% indicated better practice performance during emergencies. Thirty-eight percent applied CRM to personal crisis experiences. CONCLUSIONS: Findings support that CRM training leads to perceived improvements in performance during critical events.

Simulated Crisis in Obstetric Anesthesia: Design and Evaluation of a Distance Education Presentation.

Patient simulators are useful tools for training residents and all levels of medical personnel. Simulator usefulness, in small group sessions, is limited by the costs of training large numbers of people. We present an interrupted methodology designed to involve a large group at a location remote from the simulator. The goal was to enable the remote participants to take part in decision making while under time pressure. Two volunteers were chosen as hands-on participants while eighteen remaining anesthesiology residents observed from a lecture room via a closed circuit audio/video feed. A series of five crises in obstetric anesthesia was presented. After each crisis the simulation was paused and the observers were given three minutes to formulate a differential diagnosis and plan to be carried out. At the end of the session facilitators led a debriefing session with all participants. Surveys completed after the simulation indicated that most residents felt personally involved in the simulation, despite being physically removed from it. Surveys also showed that residents believed they learned more from this format than they would have from a lecture. Residents recalled an average of 3.4 crises two days after the session. This paper presents a model for distance education using a simulator and shows that residents believed remote, interrupted, interactive simulator training is valuable. The interrupted nature and involvement of remotely located peers differentiate this methodology from a passive viewing of a remote session. Further study is warranted to quantify the effectiveness of group and/or distance training with a simulator.

Practical training for postgraduate year 1 surgery residents.

BACKGROUND: Surgical interns accept significant patient care responsibilities with minimal orientation. We have developed a multifaceted training program for incoming surgical interns in which learning in a simulated environment plays a key role. The purpose of this study was to evaluate resident perceptions of simulated clinical calls as an educational modality and to measure the effect on self-ratings of confidence. METHODS: A multidisciplinary team compiled 15 clinical scenarios. Simulated nurse-to-resident clinical call sessions were held on 3 separate days. Daily course evaluation surveys and identical precourse and postcourse confidence surveys were completed. RESULTS: The resident confidence measure increased significantly postcourse (6.73 versus 8.35, P <0.03). The evaluation survey score averaged 4.35 out of 5. CONCLUSIONS: Simulated clinical call sessions were well received and resulted in a significant increase in resident confidence levels. Based on this modality's apparent efficacy and ease of implementation, we offer it as a useful educational tool for incoming postgraduate year-1 surgical residents.

Central venous pressure measurements: peripherally inserted catheters versus centrally inserted catheters.

OBJECTIVE: To determine whether central venous pressure measurements taken from a peripherally inserted central catheter (PICC) correlate with those from a centrally inserted central catheter (CICC). DESIGN: A pilot bench study followed by a prospective, non-blinded, clinical comparison. SETTING: A 16-bed medical coronary intensive care unit and a 30-bed surgical intensive care unit at a university hospital. PATIENTS: Seven surgical intensive care unit patients and five medical coronary intensive care unit patients. INTERVENTIONS: During the bench study, a simple manometer system was set up to test the catheters. During the clinical study, measurements of central venous pressure were recorded from patients who had an indwelling CICC and PICC concomitantly. Positions of the catheter tips in the chest were verified by radiography. Paired central venous pressure measurements were taken from 19-gauge dual-lumen PICCs and from 7-Fr, 16-gauge, 18-gauge, and pulmonary artery catheter CICCs, all with continuous pressure infusion devices. MEASUREMENTS AND MAIN RESULTS: Bench work showed that PICCs, because of their longer length and narrower lumen, have a higher inherent resistance, which can be overcome with a continuous infusion device. During the clinical study, three to 12 paired, digital, central venous pressure measurements were recorded from each of 12 patients for a total of 77 data pairs. Measurements were recorded at end-expiration. Mean central venous pressure from the CICCs was 11 + 7 mm Hg, and from the PICCs was 12 + 7 mm Hg. PICC pressure versus CICC pressure correlated (r = 0.99) for all data pairs. Analysis by repeated measures showed PICC central venous pressure more than CICC central venous pressure by 1.0 + 3.2 mm Hg (p = 0.02). CONCLUSIONS: PICCs can be used to measure central venous pressure and to follow trends in a clinical setting when used with a pressure infusion device to overcome the natural resistance of the PICC. Central venous pressure recorded via PICCs is slightly higher, but the difference is clinically insignificant.

Crisis resource management among strangers: principles of organizing a multidisciplinary group for crisis resource management.

Patient safety depends on the skills, vigilance, and judgment of trained individuals working as members of a clinical team that includes anesthesiologists, surgeons, nurses, and technicians. Now, as never before, safe outcome depends both on better knowledge and better management. This requires organization of caregivers, who may be strangers from diverse disciplines, into teams. One can drill an individual to work safely alone. One can rehearse a series of scenarios with small groups (who regularly work together) to improve performance. But what does one do with an unrehearsed group, called together in an emergency from several different disciplines, usually including Anesthesia. These people may not know each other, their roles, their special skills, and may even be hazy about each other's goals. Rapid organization of such an ad hoc team becomes a critical priority where patient safety is at stake. The way by which such an ad hoc team from several disciplines can rapidly be helped to function effectively together is by teaching all the "strangers" the principles of Crisis Resource Management. These principles are not as well-presented in a written text or lecture format, as one cannot introduce the sense of urgency that emotionally charges and changes the impact. We believe the best teacher is experience gained in a realistic simulated environment using a model driven, full human simulator. This simulated environment is safe for both patient and trainee.

Tactile feedback is present during minimally invasive surgery.

BACKGROUND: The applications of minimally invasive surgery (MIS) and laparoscopy are rapidly expanding. Despite this expansion, our understanding of the importance of haptic feedback during laparoscopic surgery is incomplete. Although many surgeons believe that the use of minimally invasive techniques eliminates force feedback and tactile sensation (haptics), the importance of haptics in MIS has not been fully evaluated. There is considerable interest in the development of simulators for MIS even though the importance of force feedback remains poorly understood. This study was designed to determine the ability of experienced surgeons to interpret haptic feedback with respect to texture, shape, and consistency of an object. STUDY DESIGN: A randomized, single-blinded study was designed. Twenty surgeons were presented objects in a random order, with participants blinded as to their identity. Inspection by direct palpation, conventional instruments, and laparoscopic instruments was performed on all objects. Statistic analysis of the data was performed using chi-square analysis and, when appropriate, a Fischer exact probability test. RESULTS: Direct palpation was associated with the highest accuracy for shape identification and was superior to both conventional instruments (p < 0.001) and laparoscopic instruments (p<0.001). Fine texture analysis with either a conventional instrument or a laparoscopic instrument was superior to direct palpation (p < 0.05). Finally, the three methods of analysis were comparable for consistency analysis. CONCLUSIONS: These data indicate that laparoscopic instruments do, in fact, provide surgeons with haptic feedback. Interpretation of the texture, shape, and consistency of objects can be performed. In some situations, laparoscopic instruments appear to amplify the haptic information available. Our ongoing work is directed at further defining force interactions.

Arterial-pulse oximetry loops: a new method of monitoring vascular tone.

OBJECTIVE: We report the off-line calculation of the vascular compliance of the finger and suggest the continuous on-line use of this methodology as an aid to monitoring the peripheral vascular resistance. This method consists of the simultaneous analysis of the waveform signals from the pulse oximeter monitors and the arterial pressure as indicators of "volume" and pressure respectively to continuously calculate the vascular "compliance" (volume change per unit pressure change). This should be seen as a "relative compliance" as the pulse plethysmograph signal is not calibrated. This new methodology allows for continuous monitoring of peripheral vascular compliance as a beat-to-beat indicator of peripheral vascular resistance. The vaso-constrictors, phenylephrine and ephedrine, were shown to decrease the compliance as predicted. METHODS: The arterial pressure and pulse oximeter waveforms were obtained during routine anesthetic care. The waveforms were collected with a computer data-acquisition system and then analyzed "off-line" as an indirect indicator of total vascular tone. Demographic and clinical information including drug administration were recorded. RESULTS: A case report is presented using this new form of analysis. Vascular compliance changes induced by phenylephrine and ephedrine were studied. A dose response curve of peripheral vascular compliance to phenylephrine was generated from these data. CONCLUSIONS: By plotting the pulse oximeter waveforms versus the arterial waveforms, multiple volume versus pressure (relative compliance) loops were obtained. Analysis of these loops may assist in the monitoring of vascular compliance.

A laboratory assessment of oxygen delivery from a portable chemical generator.

A simple portable chemical oxygen generator was tested in the laboratory. The device is designed for use by the public as an oxygen supply until an emergency team arrives with appropriate oxygen cylinders. The generator was found to supply a mean (SD) flow of oxygen of 3.6 (0.01) l.min-1 for 12.5 (range 12.4-12.6)min. The mean (SD) total volume of oxygen produced was 47(0.17) l. The supplied oxygen mask was a variable performance type with the problems and limitations inherent in this design; an oxygen flow of 8 l.min-1 is required to provide 40% oxygen and most of the oxygen is wasted and not available to the patient. This poses a serious limitation to any device which has a limited capability (in flow and/or total volume) for producing oxygen.

The peripheral pulse wave: information overlooked.

although the waveform derived from a peripheral pulse monitor or pulse oximeter may resemble an arterial pressure waveform, it is in fact a visualization of blood volume change in transilluminated tissue caused by passage of blood: an indication of perfusion or blood flow. Most currently available pulse oximeters indicate this flow, but few display it in usable form. Since adequate tissue blood flow is a prerequisite for normal metabolic activity, it is a parameter that should merit a place in standard anesthesia or intensive care monitors. That the peripheral tissue blood flow is not routinely displayed may be in part due to the difficulty in quantifying data obtained: flow is not accurately measured as simply as pressure, even by invasive means. It is in the pattern of the waveform that beat-to-beat changes in stroke volume can be better seen than measured, or in the interaction of ventilation and circulation that tests general circulatory performance. The origin and interpretation of these changes are discussed and illustrated with examples. We indicate how new physiological tests of autonomic function and cardiac preload can be developed using pulse plethysmography. The importance and application of the Valsalva effect on the waveform is emphasized. This effect is particularly applicable for monitoring adequate fluid loading and the action of vasodilator drugs, which are both important in anesthesia. Differences between the arterial pulse pressure wave and tissue flow wave are discussed, as well as the cause of certain artifacts, including the wandering dicrotic notch.

Thrombelastography changes in pre-eclampsia and eclampsia.

We have measured platelet count, bleeding time and thrombelastography (TEG) variables and the correlation between these variables in 49 pregnant patients presenting with pre-eclampsia or eclampsia. Eighteen patients (37%) had a platelet count < or = 150 x 10(9) litre-1 and seven (14%) had a platelet count < or = 100 x 10(9) litre-1. Bleeding time was prolonged > 9.5 min in 13 (27%) patients and the TEG was abnormal in four (8%). The TEG variables, k time and maximum amplitude (MA) had a strong correlation with platelet count (k time-platelet count < or = 150 x 10(9) litre-1, r = -0.68, P = 0.003, platelet count < or = 100 x 10(9) litre-1, r = -0.84, P = 0.02; MA--platelet count < or = 150 x 10(9) litre-1, r = 0.72, P = 0.001, platelet count < or = 100 x 10(9) litre-1, r = 0.78, P = 0.04). There was no correlation between bleeding time and thrombocytopenia (platelet count < or = 150 x 10(9) litre-1, r = -0.18, ns; platelet count < or = 100 x 10(9) litre-1, r = 0.09, ns). There was no correlation between bleeding time and any measured TEG variable. Of the 10 (20%) patients with an adequate platelet count (> 100 x 10(9) litre-1) but prolonged bleeding time, the TEG was normal, suggesting adequate haemostasis. An MA of 53 mm, which is the lower limit for normal pregnancy, correlated with a platelet count of 54 x 10(9) litre-1 (95% confidence limits 40-75 x 10(9) litre-1). Although the number of patients with severe thrombocytopenia was small, a platelet count of 75 x 10(9) litre-1 should be associated with adequate haemostasis.

"Helper:" A critical events prompter for unexpected emergencies.

OBJECTIVE: The medical practitioner is faced with an increasing list of protocols and algorithms related to patient care. These recommendations are often difficult to recall, particularly in stressful emergency situations. Using advanced cardiac life support (ACLS) protocols, we built a computer-based system to exhibit precompiled response plans for medical emergencies. To validate the usefulness of this prompting device, we tested application of two of the nine ACLS algorithms, pulseless ventricular fibrillation/ventricular tachycardia (Vfib/Vtach) and bradycardia, in a simulated operating room (OR) environment. METHODS: The system utilized the software authoring system IconAuthor (Aimtec Inc., Nashua, NH) and a touch-screen monitor (DiamondScan, Microtouch, Methuen, MA). Prior to testing our system, all 39 subjects were given time to familiarize themselves with its operation. Subsequently, all subjects were videotaped while managing a standard simulated anesthetic. During the anesthetic, the subjects were presented with two emergency scenarios, not viewed during the familiarization period. The electrocardiographic (EKG) signals for normal sinus rhythm, ventricular fibrillation, and second-degree heart block were presented. By random selection, the prompter was available to half of the subjects for help with arrhythmia management (experimental group), while to half it was not (control group). RESULTS: A total of 39 subjects completed the exercise. Use of the prompter enabled significantly more subjects to administer correct drugs and dosages during ventricular fibrillation. The correct lidocaine dose was chosen more often by the experimental group than by the control (p = 0.015); similarly MgSO4 was appropriately ordered more often in the experimental group (p = 0.003). During second-degree heart block, atropine was correctly followed with a dopamine infusion (p = 0.004), and epinephrine infusion was ordered for refractory bradycardia (p = 0.002) more often in the experimental than the control group. CONCLUSIONS: These data demonstrate the value of a prompting device at the anesthesia workstation. We foresee the use of such prompters in many areas of medicine.

A test to prevent subarachnoid and intravascular injections during epidural analgesia.

Not one of the present tests for the correct position of an epidural catheter can reliably detect intravascular, intrathecal and extra-epidural placement. A simple rapid test has therefore been developed. Following placement of the epidural catheter an initial aspiration test for cerebrospinal fluid and blood is performed. Air (1 ml) and then saline (2 ml) are injected through the epidural filter. The test involves 3 steps after removal of the filter: (i) the open end of the epidural catheter is lifted and the liquid meniscus present in the catheter is observed to drop rapidly; (ii) the open end of the epidural catheter is lowered and the liquid meniscus is again observed to fill the catheter with clear liquid and no blood; (iii) the presence of air in the catheter during backflow confirms the correct position in the epidural space relative to a position in the subarachnoid space. The combined steps were prospectively examined in 278 cases of surgery under epidural analgesia. The test reliably detected 5 cases of intravascular and 2 cases of subarachnoid placement. No cases of local anaesthetic toxicity or undiagnosed subarachnoid injection were noted. Not one of the 6 failures to establish epidural analgesia could be attributed to intravascular or intrathecal placement. The sensitivity, specificity and positive predictive value for correct epidural placement of the catheter were found to be 95.5%, 63.6% and 98.5% respectively. The time required to perform the test was less than 30 seconds in 92% of the cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Low dose epidural lidocaine/sufentanil is effective for outpatient lithotripsy.

Lumbar epidural analgesia was administered to 60 ASA class 1 & 2 patients with 3 ml test dose of 1.5% lidocaine and bolus of 20 ml of 0.5% lidocaine containing 0.5 microgram/kg sufentanil. Bilateral decreased lumbar cold perception was accepted as evidence of analgesia despite persisting pinprick sensation in thoracic dermatomes. Oxygen saturation (SpO2), respiratory rate, cardiovascular parameters and leg muscle strength were monitored throughout and until 1 hour afterwards. Midazolam provided light sedation and atropine bradycardia control. Verbal communication was maintained. ESWL could start within 6-10 minutes of bolus, with analgesia adequate in 86% of patients, the rest being "rescued" with 5-10 ml 0.5% lidocaine or analgesic doses (20-30 mg IV) of ketamine. Leg weakness developed in 14%, with 1 patient fully paralyzed. All resolved within 1 hour. Topical urethral analgesia was used in males where cystoscopy preceded ESWL. Phenylephrine was required once for nild systolic hypotension, otherwise blood pressures were stable. Two of 4 patients experiencing pruritus needed naloxone relief. Itching appeared in skin recovering from sensory block while visceral analgesia persists. Excessive respiratory depression was not seen.