Ronald D Stewart

Clinical trial of a new lightwand device (Trachlight) to intubate the trachea.

Background : Transillumination of the soft tissue of the neck using a lighted stylet (lightwand) is an effective and safe intubating technique. A newly designed lightwand (Trachlight) incorporates modifications to improve the brightness of the light source as well as flexibility. The goal of this study was to determine the effectiveness and safety of this device in intubating the trachea of elective surgical patients. Methods : Healthy surgical patients were studied. Patients with known or potential problems with intubation were excluded. During general anesthesia, the tracheas were intubated randomly using either the Trachlight or the laryngoscope. Failure to intubate was defined as lack of successful intubation after three attempts. The duration of each attempt was recorded as the time from insertion of the device into the oropharynx to the time of its removal. The total time to intubation (TTI), an overall measure of the ease of intubation, was defined as the sum of the durations of all (as many as three) intubation attempts. Complications, such as mucosal bleeding, lacerations, dental injury, and sore throat, were recorded. Results : Nine hundred fifty patients (479 in the Trachlight group and 471 in the laryngoscope group) were studied. There was a 1% failure rate with the Trachlight, and 92% of intubations were successful on the first attempt, compared with a 3% failure rate and an 89% success rate on the first attempt with the laryngoscope (P not significant). All failures were followed by successful intubation using the alternate device. The TTI was significantly less with the Trachlight compared with the laryngoscope (15.7 ± 10.8 vs. 19.6 ± 23.7 s). For laryngoscopic intubation, the TTI was longer for patients with limited mandibular protrusion and mentohyoid distance, with a larger circumference of the neck, and with a high classification according to Mallampatti et al. However, there was no relation between the TTI and any of the airway parameters for Trachlight. There were significantly fewer traumatic events in the Trachlight group than in the laryngoscope group (10 vs. 37). More patients complained of sore throat in the laryngoscope group than in the Trachlight group (25.3% vs. 17.1%). Conclusions : In contrast to laryngoscopy, the ease of intubation using the Trachlight does not appear to be influenced by anatomic variations of the upper airway. Intubation occasionally failed with the Trachlight but in all cases was resolved with direct laryngoscopy. The failures of direct laryngoscopy were resolved with Trachlight. Thus the combined technique was 100% successful in intubating the tracheas of all patients.

Effect of varied training techniques on field endotracheal intubation success rates

A pool of 146 mobile intensive care unit paramedics was divided into four equal groups and trained in the technique of direct laryngoscopic endotracheal intubation of cardiac arrest or deeply comatose patients. Group 1 was selected from supervisors and crew chiefs and trained as preceptors. The remaining paramedics were assigned to three other study groups. Groups 1 and 2 were trained with a didactic presentation followed by manikin practice, an animal laboratory exercise, and operating room experience. Group 3 had no OR experience; Group 4 had only didactic/manikin training. Intubations were observed by preceptors on scene. During the study period of 27 months, 689 of 763 patients (90.3%) were successfully intubated by 122 paramedics. While results suggest variation in skill levels according to training group (Group 1, 92.4%; Group 2, 87.6%, Group 3, 83.3%; Group 4, 76.9%), statistical analysis allowing for the variables of seniority and number of intubations performed by personnel failed to reveal differences in groups attributable to training programs. Complication rates were relatively low for all groups, the most common being prolonged intubation attempts. A significant improvement in the skill was seen as the study progressed when groups are pooled and compared. The findings suggest that endotracheal intubation of deeply comatose or cardiac arrest patients is a field procedure that can be performed safely and skillfully by well-monitored paramedical personnel. Operating room or animal laboratory experience may increase initial success levels, but these factors do not appear to greatly influence eventual performance or incidence of complications of the procedure.

Nitrous oxide sedation/analgesia in emergency medicine

Nitrous oxide:oxygen mixtures are safe and effective sedative/analgesic agents for use in emergency medicine. They are suitable for prehospital care because of their safety, rapid onset, and short duration of action. The self-administered form of a 50:50 mixture is the most acceptable system, but other methods of administration should be investigated, particularly in the ED setting. While there are unresolved questions concerning the use of nitrous oxide as an anesthetic and analgesic agent, it is difficult to extrapolate many of the findings to the low-dose, patient-controlled 50:50 mixture used in emergency medicine. Use of the gas mixture in a variety of clinical settings has been associated with no major adverse occurrences, and experience continues to support its safety. Future possibilities for study include the use of the gas mixture in combination with other agents or TENS. No one drug can be considered a panacea for all painful states. Nitrous oxide:oxygen mixtures certainly do not meet all the criteria for the ideal analgesic. Those clinicians who seek a safe and effective sedative/analgesic for mild to moderate pain will be satisfied that we can now offer more to our patients in the early management of their problems.

Use of a Lighted Stylet for Guided Orotracheal Intubation in the Prehospital Setting

Management of the airway in acutely injured patients demands special skills of the emergency physician. A technique of light-guided orotracheal intubation has been described in the literature and was performed under protocol by resident physicians in an urban mobile intensive care system. The method utilizes a flexible lighted stylet to provide a guide to correct placement through transillumination of the soft tissues of the neck. During the 12-month period of the study, 24 intubations were attempted in 21 patients using this technique. Twenty-one attempts (88%) were successful. The average time for intubation was 20 seconds, with none requiring more than 45 seconds. Fourteen intubations (67%) were successful on the first attempt. Of the three unsuccessful procedures, two were attempted in bright sunlight, and all three patients had vomited prior to the attempts. Trauma to the soft tissues in one successfully intubated patient was the only complication reported with the technique. The advantages of this method, including rapidity of intubation, ability to intubate without manipulation of the head or neck, and the apparently few complications, make it particularly attractive to emergency personnel. We conclude that guided orotracheal intubation using a lighted stylet is an effective and safe method of emergency intubation, even in the adverse prehospital environment.

EMS Agenda for the Future: Where We Are … Where We Want to Be

During the past 30 years, emergency medical services (EMS) in the United States have experienced explosive growth. The American health care system is now transforming, providing an opportune time to examine what we have learned over the past three decades in order to create a vision for the future of EMS. Over the course of several months, a multidisciplinary steering committee collaborated with hundreds of EMS-interested individuals, organizations, and agencies to develop the EMS Agenda for the Future. Fourteen EMS attributes were identified as requiring continued development in order to realize the vision established within the Agenda. They are integration of health services, EMS research, legislation and regulation, system finance, human resources, medical direction, education systems, public education, prevention, public access, communication systems, clinical care, information systems, and evaluation. Discussion of these attributes provides important guidance for achieving a vision for the future of EMS that emphasizes its critical role in American health care.

Role of the physician in the prehospital setting

Despite the initial successes achieved in early emergency medical services (EMS) systems, many prehospital care services have developed without the intense involvement of physicians whose interest fueled the first experimental medical programs of prehospital care. Among a myriad of variables affecting EMS is the important element of intense, authoritative physician involvement in education, field supervision, and research. Recognizing this problem, many states now have legislated that EMS systems be closely supervised by medical directors. Political and financial constraints often have diluted medical influence and authority, and intense, direct field supervision is the exception rather than the rule. successful EMS systems can demonstrate their influence on morbidity and mortality through appropriate data collection and quality assurance programs. Such programs appear to have in common the element of direct involvement of competent physicians in initial training, field supervision, and policy decisions. Until recently, full-time compensated physician involvement in EMS has been regarded as unnecessary or impractical. Certainly in large urban centers such full-time involvement is mandatory. While in smaller municipalities full-time commitments may be unnecessary, partial compensation for time dedicated to EMS pursuits should be part of the EMS budget. It has been the experience of major urban EMS systems that field participation by physicians has lent irrefutable credibility to the authority of medical directors. Beyond the obvious benefits of quality assurance and supervision, the in-field EMS physician provides the impetus and leadership for EMS research conducted at the street level. Because EMS is the practice of medicine through physician surrogates in a prehospital setting, it sets the stage and tone for subsequent patient care and outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial blood gases before, during, and after nitrous oxide: Oxygen administration

The use of nitrous oxide as an anesthetic or analgesic agent frequently raises concerns about the possibility of post-inhalational diffusion hypoxemia. We undertook a study in 20 healthy volunteers to determine whether hypoxemia occurs after the self-administration by face mask of a 50:50 mixture of nitrous oxide and oxygen for 15 minutes, followed by breathing room air. Blood gases were measured through an in-dwelling arterial cannula before, during, and after inhalation of the mixture, at time O, five, ten, and 15 minutes, and then 30 seconds, 45 seconds, 2 1/2 minutes, five, and ten minutes following room air breathing. Ten of the 20 subjects breathed a control gas, a mixture of 50% nitrogen: 50% oxygen. No subject demonstrated arterial hypoxemia at any time before, during, or after self-administration of the gas mixture. In the ten subjects who self-administered the control gas there were no significant differences in the PaO2 values while they breathed either gas at any corresponding sampling time. We conclude that diffusion hypoxia is not seen in normal subjects following self-administration of a mixture of 50:50 nitrous oxide and oxygen.

Tactile orotracheal intubation

A previously described method for tactile (digital) endotracheal intubation was refined for use in deeply comatose patients. This technique, consisting of introduction of the endotracheal tube by palpation of the epiglottis, was practiced in cadaver subjects and then applied in both field and emergency department settings. Because the procedure can be carried out without movement of the head and neck and even with an immobilization device in place, it was found particularly suitable in trauma patients who might have suffered injury to the cervical spine. An added advantage is the ease of performance despite secretions or blood in the upper airway. This technique should prove useful to clinicians involved in the early care of critically ill or injured patients.

Success rates of blind orotracheal intubation using a transillumination technique with a lighted stylet

The technique of guided orotracheal intubation using a lighted stylet depends on the transillumination of the soft tissues of the neck to direct the tube through the glottis and into the trachea. We conducted an operating room study of this technique, recording success rates and intubation times of 50 patients undergoing elective surgery. All patients were intubated successfully, 35 of 50 (70%) on the first attempt, 12 of 15 (80%) on the second attempt, and three of three (100%) on the third attempt. The average time for intubation was 37 seconds. A new design of the lighted stylet method resulted from the experience gained. Intubator training and experience influenced initial success rates, and the cadaver laboratory was of particular value in teaching the technique.

Gastrointestinal transit times of cathartics combined with charcoal

Oral activated charcoal usually is administered in toxic ingestions along with a cathartic. A study was done in volunteers to determine the rapidity of gastrointestinal transit when activated charcoal was administered with various cathartics. A control of activated charcoal was compared to the gastrointestinal transit times of activated charcoal plus the cathartics magnesium citrate, magnesium sulfate, or sorbitol. Activated charcoal alone produced a mean transit time of 23.5 hours; magnesium citrate catharsis occurred in 4.2 hours, magnesium sulfate catharsis occurred in 9.3 hours, and sorbitol catharsis occurred in 0.9 hours. Sorbitol clearly was the most rapidly acting cathartic.