Neuromuscular blockade for critical patients in the emergency department

Acute airway management in the emergency department by non-anesthesiologists

PURPOSE

The responsibility of acute airway management often falls into the hands of non-anesthesiologists. Emergency physicians now routinely use neuromuscular blockade to facilitate intubation. The literature in support of this practice has almost exclusively been published in emergency medicine (EM) journals. This body of literature is presented and issues of educational support are discussed.

SOURCE

A narrative review of the literature on the practice of airway management by non-anesthesiologists.

PRINCIPAL FINDINGS

A significant proportion of acute airway management occurring outside the operating room is being performed by non-anesthesiologists. Rapid sequence intubation (RSI) is recognized as a core procedure within the domain of EM. RSI is being performed routinely by emergency physicians practicing in larger centres. Anesthesiologist support for the practice of RSI by non-anesthesiologists has been weak. Formal educational support outside of postgraduate training in the form of dedicated programs for advanced airway management are now being offered. The majority of the literature on the use of RSI by non-anesthesiologists represents retrospective case series, observational studies and registry data published in EM journals. The reported success rates for RSI performed by non-anesthesiologists is high. Complication rates are significant, however reporting consistency has been poor.

CONCLUSIONS

The role of non-anesthesiologists in acute airway management is significant. Despite shortcomings in methodology, current evidence and practice supports the use of RSI by trained emergency physicians. Constructive collaborative efforts between anesthesiology and EM need to occur to ensure that educational needs are met and that competent airway management is provided.

Paediatric intubation in Scottish emergency departments

BACKGROUND

Intubation of children in the emergency department setting is uncommon. This prospective observational study examines the practice of paediatric intubation in Scottish adult/paediatric urban emergency departments.

METHODS

A prospective observational study of every intubation attempt was performed in seven urban Scottish emergency departments in 1999 and 2000. Children were defined as those patients who were less than 13 years of age on the day of presentation. Prehospital intubations were only included if they were performed by a mobile medical team doctor from one of the seven hospitals.

RESULTS

A total of 1713 patients were identified, 44 of whom (2.6%) were children. The median age was 4 years (range 0-12 years), and 57% (25 of 44) of intubations were performed on patients with traumatic injuries. Emergency physicians attempted intubation in 27% (12 of 44) of cases, anaesthetists in 73% (32 of 44); 18% (eight of 44) of patients were intubated in nontraumatic cardiac arrest, 68% (30 of 44) underwent rapid sequence intubation (RSI), one (2%) had inhalational anaesthesia and 13 (30%) were intubated without drugs. Eighty per cent (35 of 44) of patients were intubated at the first attempt; eight patients required two attempts, and one required three attempts. Three children were intubated prehospital by mobile medical teams. Emergency physicians intubated more patients with 'physiological compromise' (100% vs 91%).

CONCLUSIONS

Paediatric intubation in the emergency department is uncommon. Collaboration and appropriate training for doctors in emergency medicine, anaesthesia and paediatrics is essential.

Predicting adverse outcomes in a diagnosis-based protocol system for rapid sequence intubation

Our ED at Louisiana State University developed a unique approach to airway management by having four diagnosis-based protocols for rapid sequence intubation (RSI). This study examines protocol use and outcome from RSI in an academic ED. The study objective was to identify variables that are predictive of adverse outcomes in patients requiring RSI. This was a 4-year prospective, observational, data-gathering study of all intubations in an academic ED setting with >250,000 patient visits per year. Four protocols were established for 1) children <10 years of age, 2) adults with increased intracranial pressure, 3) adults with chronic obstructive pulmonary disease/asthma, and 4) other adults not fitting B or C. A special continuing quality improvement (CQI) committee was established to examine each case of RSI. Prospective data were collected, including age, race, gender, protocol, diagnostic group, intubation indication, and preintubation oxygen saturation. Diagnostic group was categorized as medical, blunt trauma, or penetrating trauma. Adverse outcome was defined as any case with hemodynamic changes, those requiring surgical or bronchoscopic intervention, and those requiring more than three attempts at intubation. Data were analyzed using univariate analysis, logistic regression, and a binomial regression tree analysis with SPSS 9.0 (Chicago, IL) and Answer Tree (SPSS). A total of 1,320 consecutive intubated patients were included. Protocol A was used in 4%, B in 43%, C in 15%, and D in 38%. Significant differences in number of cases with adverse outcome were based on protocol (P =.03) and final diagnosis (P <.03). Protocol C was less likely to be associated with adverse outcome than protocol D (odds ratio [OR] = 0.2, 95% confidence interval [CI] = 0.1-0.7). Penetrating trauma was more likely to be associated with adverse outcome (OR = 1.8, 95%, CI = 1.1-3.2) than blunt trauma. A regression tree analysis yielded the following, all cases using protocol A or C or medical cases using B had an adverse event in 11 of 458 (2.4%), whereas nonmedical cases using protocols B or D and medical cases using D had adverse outcomes in 73 of 862 cases (8.5%). The decision rules lead to a better classification of cases with adverse outcomes (2.4 vs 8.5%, of = 6.1%, 95% CI = 3.7-8.4). Adult trauma patients who fit the protocols B or D or adult medical patients who fit protocol B were at higher risk for adverse outcomes with RSI. This could alert the physician to a population at higher risk for adverse outcomes. Variables available in a diagnosis-based protocol RSI system can be used to predict adverse outcome among patients requiring RSI.

[Rapid sequence intubation in emergency: is there any place for fentanyl?]

OBJECTIVES

Rapid sequence intubation (RSI) with the association of etomidate and succinylcholine is the French "Gold standard" for urgent "full stomach" endotracheal intubations. The aim of this study is to assess the fentanyl as a co-induction agent to take over the sedation between the RSI and the keeping of sedation, which is a critical period in which harmful neuro-vegetatives events, and awakening signs are frequently seen.

STUDY DESIGN

Randomized, double blind controlled prospective study, after acceptation by the local ethical committee.

PATIENTS AND METHODS

Three groups of patients undergoing RSI in the intensive care unit and by the out-of-hospital medical team were compared: group A patients received fentanyl 3 micrograms kg-1 during RSI, before paralysis was induced. Group B patients received the same dose of fentanyl immediately after endotracheal intubation. Group C patients did not received fentanyl (control group). Outcome measures were awakening signs arrival (respiratory movements, eyes opening, spontaneous limb movements), Ramsay score assessment, and haemody namics. Attempt at intubation and vomiting incident were also measured. Discrete data were compared by chi-2 analysis, continuous data were compared with two-way analysis of variance. A p value < 0.05 was the significant threshold.

RESULTS

Thirty-six patients were enrolled and completed the study. All the included patients presented awakening signs. The use of fentanyl did not prevent the recourse of other sedative medications. Ten minutes after endotracheal intubation, significant differences has been noticed for the awakening signs arrival between fentanyl groups (A: 42% and B: 36%) and control group (C: 77%). The Ramsay score evolution follows the same variation. All the patients were intubated on the first attempt, there was no vomiting incident noticed.

CONCLUSION

The use of fentanyl, as a co-induction agent with etomidate and succinylcholine during RSI, allows a significant delay of the awakening signs arrival and attenuate the neurovegetative response during the minutes after endotracheal intubation after RSI, without deleterious haemodynamic effects.

An analysis of advanced prehospital airway management

Considerable controversy persists regarding the optimal means and indications for airway management, the utility of paralytic agents to facilitate intubation, and the indications for advanced airway access techniques in the prehospital setting. To describe the use of intubation and advanced airway management in a system with extensive experience with both the use of paralytic agents and surgical airway techniques, a retrospective review was conducted of all prehospital airway procedures from January 1997 through November 1999. Data collected included demographics, airway management techniques, use of paralytic agents, and immediate outcome. The results showed there were 2700 patients intubated out of 50,118 patient encounters (5.4%). The indications for intubation included medical emergency in 82% of patients and traumatic injury in 18%. Fifty percent of patients were intubated with the use of succinylcholine. The overall oral intubation success rate was 98.4% and definitive airway access was achieved in all but 12 patients (0.6%), with 30 patients receiving surgical airway access (1%). The successful intubation rate for patients receiving paralytic agents was 97.8%. Previously published rates of prehospital surgical airway access range from 3.8 to 14.9% of patients. In this study, only 1.1% of patients required a surgical airway. We attribute this low rate to the use of paralytic agents. The availability of paralytic agents also allows expansion of the indications for prehospital airway control.

Paramedic success rate for blind nasotracheal intubation is improved with the use of an endotracheal tube with directional tip control

STUDY OBJECTIVES

Blind nasotracheal intubation (BNTI) is used to secure the airway in patients who are spontaneously breathing. The success rate for BNTI is often lower than for orotracheal intubation. We conducted this study to determine whether the use of an endotracheal tube (ETT) capable of directional tip control can improve the BNTI success rate.

METHODS

This prospective, experimental study was conducted by a state emergency medical services agency during 1997, 1998, and 1999. Consecutive patients undergoing attempted BNTI or orotracheal intubation were included. Five paramedic units were trained to use an ETT with triggeractivated distal tip directional control for BNTIs (intervention group). Ten units used conventional ETTs for BNTIs and served as concurrent controls (control group). Subjects in the 2 groups were enrolled concurrently with nonrandomized allocation based on the agency providing service. An intubation attempt was defined by tube passage, and success was defined as confirmed endotracheal placement.

RESULTS

A total of 219 BNTIs were studied (141 in the control group and 78 in the intervention group). BNTI was successful in 82 (58%) of 141 cases using conventional ETTs, and in 56 (72%) of 78 cases using directional tip control (P =.04). The overall success rate was 63%.

CONCLUSION

Use of ETTs with distal directional control is associated with a higher success rate for BNTI than conventional ETTs. Use of ETTs with directional tip control significantly improves the success rates for BNTIs.

Comparison of wire-guided cricothyrotomy versus standard surgical cricothyrotomy technique

We compared a wire-guided cricothyrotomy technique vs. standard surgical cricothyrotomy in terms of accuracy in placement, complications, performance time, incision length, and user preference. We conducted a randomized, crossover controlled trial in which Emergency Medicine (EM) attendings and residents performed cricothyrotomies by both standard and wire-guided techniques (using a commercially available kit) on human cadavers after a 15-min training session. Procedure time, incision length, and physician preference were recorded. Cadavers were inspected for accuracy of placement and complications. Airway placement was accurate in 13 of 15 cases for the standard technique (86.7%), and 14 of 15 cases for the wire-guided technique (93.3%). When comparing wire-guided vs. standard techniques, there were no differences in complication rates or performance times. The wire-guided technique resulted in a significantly smaller mean incision length than the standard technique (0.53 vs. 2.53 cm, respectively, p<0.0001). Overall, 14 of 15 physicians stated that they preferred the wire-guided to the standard technique. Our data suggest that this wire-guided cricothyrotomy technique is as accurate and timely to use as the standard technique and is preferred by our physician operators. In addition, the technique results in a smaller incision on human cadaver models.

[The use of curare-like agents in resuscitation]

OBJECTIVE

To analyse current data on use of neuromuscular blocking agents (NBA) in the intensive therapy unit (ITU) patients and to propose practice guidelines.

DATA SOURCES

We did a Medline search of French and English language articles on NBA administration in ITU patients from 1960 to 1998. Data were also selected from our own collection of articles and books.

STUDY SELECTION

Original articles, clinical cases, letters to the editor and review articles were considered.

DATA EXTRACTION

Data on pharmacology of NBA in the ITU patient were extracted, as well as data on administration patterns and cost.

DATA SYNTHESIS

The indications for myorelaxation in ITU patients include either short term use, as in anaesthesia, or long term administration for facilitation of mechanical ventilation, control of increased intracranial pressure, status epilepticus, tetanus and oxygen demand in case of muscular hyperactivity, diagnostic and therapeutic procedures facilitation. A beneficial effect of NBA on the prognosis of the disease for which these agents have been used is not yet proven. Suxamethonium, because for its short onset time and duration of action, is the agent of choice for endotracheal intubation if myorelaxation is required. Among the benzylisoquinolines, atracurium and besilate of cisatracurium are convenient agents in ITU patients, whereas mivacurium is of no special interest. Among the aminosteroids, pancuronium and vecuronium are the most often used agents in the ITU. Rocuronium has not yet been extensively assessed. Myorelaxants carry risks for morbidity and mortality. The difficulty to assess the neurological status and the level of sedation is a recognised adverse effect. An accidental disconnection from the circuit and the resulting asphyxia is nowadays recognised without delay by the ventilator. NBAs increase the rate of bronchopulmonary infections. Cardiovascular complications include extreme bradycardia or sinus arrest following vecuronium administration, and cardiac arrest after suxamethonium injection mainly in burned or traumatised patients. Conversely to anaesthesia, NBAs do not carry a significant risk for anaphylactic or anaphylactoid complications in the ITU. Tachyphylaxis occurs mainly in burns and other pathologies modifying acetylcholine receptors. Neuromuscular complications include myopathy from steroids, postparalytic syndrome, deconditioning syndrome and intensive care polyneuropathy. Prolonged curarisation after discontinuation of NBA administration has a multifactorial origin and must be differentiated from neuromuscular complications. For prolonged neuromuscular blockade, pancuronium, vecuronium and atracurium are the agents of choice. The association with an adequate sedation is essential. Assessment of depth of neuromuscular blockade is not based on clinical symptoms but on train-of-four (TOF) twitch monitoring. A convenient basic relaxation is usually obtained with the suppression of the two last responses to TOF.

CONCLUSION

The use of NBA in ITU patient should result from a rational decision making procedure, the blockade titrated with a TOF monitor and maintained as superficially and shortly as possible.

Complications of emergency intubation with and without paralysis

Expert and definitive airway management is fundamental to the practice of emergency medicine. In critically ill patients, rapid sedation and paralysis, also known as rapid-sequence intubation, is used to facilitate endotracheal intubation in order to minimize aspiration, airway trauma, and other complications of airway management. An alternative method of emergent endotracheal intubation, intubation minus paralysis, is performed without the use of neuromuscular blocking agents. The present study compared complications of these two techniques in the emergency setting. Sixty-seven intubations minus paralysis were prospectively compared with 166 rapid-sequence intubations. Complications were greater in number and severity in the nonparalyzed group and included aspiration (15%), airway trauma (28%), and death (3%). None of these difficulties were observed in the rapid-sequence group (P < .0001). These results show that rapid-sequence intubation when compared with intubation minus paralysis significantly reduces complications of emergency airway management and should be made available to emergency physicians trained in its use.

Rapid-sequence intubation at an emergency medicine residency: success rate and adverse events during a two-year period

OBJECTIVES

Rapid-sequence intubation (RSI) is an active airway intervention used frequently in emergency medicine (EM). The authors hypothesized that RSI can be performed safely in the setting of an EM training program at a tertiary care center.

METHODS

Observational study of RSI at an urban ED/Level 1 trauma center with annual census of 100,000 patients. Consecutive patients who underwent RSI during a two-year period were studied. Data included age, gender, type of patient (medical/trauma), indication for intubation, number of intubation attempts (laryngoscope passes), training level of operator, and major immediate adverse events (clinical deterioration within 10 minutes of RSI).

RESULTS

RSI was used in 417 of 596 (70%) critically ill patients requiring emergent intubation. The patient demographic distribution was the following: adults 89.7%, male 58%, and trauma 44%. Primary indications for intubation among RSI patients were as follows: mechanical ventilation 57.4%, airway protection 41.3%, and cardiac arrest 1.3%. Distribution of intubations by level of EM training was PGY1, 5%; PGY2, 52%; PGY3, 40%; and attendings, 3%. Intubations were successfully completed within two attempts in 97% of the patients. Major immediate adverse events were encountered in six patients (1.4%) (hypotention=2, hypoxemia=1, dysrhythmia=3). There was no death attributable to RSI. The rate of intubations requiring two or fewer attempts and without major immediate adverse events was 96%. Three patients required cricothyrotomy.

CONCLUSION

In the setting of an EM residency at a tertiary care ED, RSI can be performed successfully with few major immediate adverse events.

Rapid sequence induction for intubation by an aeromedical transport team: a critical analysis

Airway control is the initial priority in the management of the injured patient. The purpose of this investigation was to evaluate the experience of an aeromedical transport team in the utilization of rapid sequence induction (RSI) for endotracheal intubation in the prehospital setting. Records of a consecutive series of injured patients undergoing RSI between June 1988 and July 1992 by a university-based aeromedical transport team were reviewed for demographics, intubation mishaps, and pulmonary complications. The relationship between intubation mishaps and pulmonary complications was analyzed. Eighty-four patients were studied with a mean age of 30.8 +/- 15.3 years. The mean Revised Trauma Score was 11.3 +/- 2.4, and the mean Injury Severity Score (ISS) was 19.6 +/- 11.5. Intubation mishaps occurred in 15 patients (18%), and pulmonary complications developed in 22 (29%) of the 75 patients surviving longer than 24 hours. There was no relationship between intubation mishaps and pulmonary complications. Abbreviated Injury Scale (AIS) face score was significantly higher in patients with intubation mishaps, compared with patients without mishaps (1.1 +/- 1.2 and 0.5 +/- 0.9, respectively, P < .05, Wilcoxon rank-sum). ISS and AIS chest were higher in patients with pulmonary complications, compared with those without (25.7 +/- 12.6 and 17.4 +/- 10.3 and 2.2 +/- 1.8 and 1.0 +/- 1.5, ISS and AIS respectively; P < .05, Wilcoxon rank-sum). Eighty-one patients (96%) underwent successful RSI, 73 (87%) on the first attempt. Failure to intubate occurred in three patients (4%). Performed under strict protocol by appropriately trained aeromedical transport personnel, RSI is an effective means to facilitate endotracheal intubation in the injured patient requiring definitive airway control. Pulmonary complications were related to injury severity and not to intubation mishaps.

[Rapid sequence anesthetic induction via prehospital tracheal intubation]

The choice of sedation for emergency intubation remains controversial. This lack of consensus has led to various sedation protocols used in French prehospital care setting. A review of data from the literature suggests that the association etomidate-suxamethonium is probable the best choice for rapid sequence intubations in the prehospital setting. Its benefits include protection against myocardial and cerebral ischaemia, decreased risk of pulmonary aspiration, and a stable haemodynamic profile. Randomized studies are needed to substantiate the advantages of the association etomidate-suxamethonium for rapid sequences intubation in the prehospital setting.

Airway management in the emergency department: a one-year study of 610 tracheal intubations

STUDY OBJECTIVE

To describe the methods, success rates, and immediate complications of tracheal intubations performed in the emergency department of an urban teaching hospital.

METHODS

This was an observational, consecutive series undertaken in an urban university hospital with an emergency medicine residency training program and an annual ED census of 60,000 patients. The study population included all patients for whom intubation was attempted in the ED during a 1-year period (July 1, 1995 through June 30, 1996). At the time of each intubation, the intubator filled out an intubation data collection form. If an intubation was performed in the ED but no form was filled out, the data were obtained from the medical record.

RESULTS

A total of 610 patients required airway control in the ED; 569 (93%) were intubated by emergency medicine residents or attending physicians. Rapid-sequence intubation (RSI) was used in 515 (84%). A total of 603 patients (98.9%) were successfully intubated; 7 patients could not be intubated and underwent cricothyrotomy. In 33 patients, inadvertent placement into the esophagus occurred; all such situations were rapidly recognized and corrected. Eight (24%) of the 33 esophageal intubations resulted in a reported immediate complication. Overall, 49 patients (8.0%; 95% confidence interval [CI], 6% to 11%) experienced a total of 57 immediate complications (9.3%; 95% CI, 7% to 12%). Three patients sustained a cardiac arrest after intubation; two of these patients had agonal rhythms before intubation, and one probably had a succinylcholine-induced hyperkalemic cardiac arrest.

CONCLUSION

At this institution, the majority of ED intubations were performed by emergency physicians and RSI was the most common method used. Emergency physicians intubated critically ill and injured ED patients with a very high success rate and a low rate of serious complications.

The use of neuromuscular blocking agents in the emergency department to facilitate tracheal intubation in the trauma patient: help or hindrance?

PURPOSE

The purpose of this study is to examine the relationship between the occurrence of a difficult intubation and (1) the use of neuromuscular blocking agents (NMB) and (2) the presence of airway injuries. It is a retrospective analysis of data from a trauma registry.

MATERIALS AND METHODS

Registry records of patients (n = 160) who required emergent endotracheal intubation or establishment of a surgical airway over a 3.5-year period in the emergency department were reviewed. Risk factors for difficult intubations were identified and analyzed using multivariate logistic regression analysis.

RESULTS

NMB were used in 75% of patients requiring intubation. Fifteen percent of the intubations were considered difficult. No association was found between the presence of airway injuries and difficult intubations; however, the use of succinylcholine was associated with a lower risk of difficult intubations compared with intubations where a nondepolarizing NMB was used.

CONCLUSIONS

The use of succinylcholine may result in fewer difficult intubations in the trauma patient than when a nondepolarizing NMB is used. The presence of airway injuries did not appear to predispose to difficult intubations.

Declining rate of cricothyrotomy in trauma patients with an emergency medicine residency: implications for skills training

OBJECTIVE

To report the change in cricothyrotomy rate with emergency medicine (EM) residency development and to address the implications for training in this skill.

METHODS

A retrospective chart review was used to determine the cricothyrotomy rate at a 1,000-bed urban Level-1 trauma center with EM, surgery, and anesthesiology residencies. All adult trauma patient visits to the ED between July 1, 1985, and June 30, 1995, were reviewed. The cricothyrotomy rate was defined as the total number of cricothyrotomies per trauma admissions during a study phase.

RESULTS

The study period was divided into 3 phases. Phase 1 (academic years 1985-1989): prior to the inception of the EM residency; phase 2 (academic years 1990-1992): initiation and establishment of the residency; and phase 3 (academic years 1993-1994): full implementation of the EM residency. The cricothyrotoiny rate during phase 1 was 1.8% (95% CI: 1.6 to 2.0), vs 1.1% (95% CI: 0.0 to 2.8) and 0.2% (95% CI: 0.0 to 0.2) during phases 2 and 3, respectively.

CONCLUSIONS

The cricothyrotomy rate decreased with the full implementation of the EM residency. Whether this trend was an effect of the presence of an EM faculty and residency training program, a parallel approach to airway management nationwide, or another unidentified factor will require further investigation. Nonetheless, given the increasing rarity of this procedure, it is likely that many EM, surgical, and anesthesiology residents will not acquire clinical experience with this technique during training.

Non-operating room emergency airway management and endotracheal intubation practices: a survey of anesthesiology program directors

Airway management in the operating room is the responsibility of anesthesiologists, although a variety of personnel may be responsible for airway management outside the operating room. We conducted a survey of anesthesia program directors regarding emergency airway management practices at their institutions. A questionnaire was sent to anesthesia program directors listed in the Graduate Medical Education Directory for 1995-1996. Of the 153 programs surveyed, 134 (88%) responded. In 45% of institutions, intubations in the emergency ward (EW) were performed by emergency medical physicians, 32% by anesthesiology personnel, and 19% by both. Most intubations performed on the hospital ward were performed by anesthesiologists. Neuromuscular blocking drugs and sedative/hypnotics were used 90% and 95% of the time, respectively, by emergency medical physicians in hospitals in which they managed the airway independently. Our data serve as a snapshot of current practices. EW physicians are prominently involved in airway management in the emergency room both independently and with anesthesiologists. Airway management in trauma patients remains the domain of anesthesiologists. Anesthesiologists are most represented in airway management on hospital floors.

Rapid sequence intubation in adults with elevated intracranial pressure: a survey of emergency medicine residency programs

A questionnaire entitled "Survey of Protocols for Rapid Sequence Intubation in Previously Healthy Adults with Elevated Intracranial Pressure" was distributed to the program directors of all 100 emergency medicine residency programs listed in the Directory of Graduate Medical Education Programs in February 1995. The medical literature on rapid sequence intubation in patients with suspected intracranial pressure elevations was reviewed. The findings of the review were compared with the survey responses. Sixty-seven program directors responded to the survey. Sixty-five programs performed rapid sequence intubation in their institution. Five programs performed 0 to 10 procedures annually. Six performed 10 to 30 annually, 19 performed 30 to 50, 17 performed 50 to 100, and 18 performed more than 100. Succinylcholine and vecuronium were the most frequently used neuromuscular blockers. Midazolam and thiopental were the most frequently used sedative induction agents. Most programs use a defasciculating agent prior to succinylcholine administration. The majority of programs do not use a priming agent before the use of a nondepolarizing neuromuscular blocking agent. Intravenous lidocaine was routinely administered prior to neuromuscular blockade. Fentanyl was the most frequently used other pretreatment medication. Rapid sequence intubation is used to facilitate definitive, emergent airway management in patients with suspected intracranial pressure elevations in almost all of the emergency medicine residency programs that responded to the survey. Most of these programs follow the guidelines recommended in the medical literature. The majority of these guidelines, however, are based on statistical data performed in the laboratory or nonemergency environments. Further clinical studies in an emergency medicine environment must be performed to determine the optimal drug regimen for rapid sequence intubation in patients with elevated intracranial pressure.

Role of bedside electroencephalography in the adult intensive care unit during therapeutic neuromuscular blockade

BACKGROUND: Size, weight and technical difficulties limit the use of ponderous strip chart electroencephalographs (EEGs) for real time evaluation of brain wave function in modern intensive care units (ICUs). Portable, computer processed, bedside EEGs provide real time brain wave appraisal for some brain functions during therapeutic neuromuscular blockade when the visual clues of the cerebral function disappear. RESULTS: Critically ill ICU patients are frequently placed in suspended animation by neuromuscular blockade to improve hemodynamics in severe organ system failure. Using the portable bedside EEG monitor, several cerebral functions were monitored continuously during sedation of selected patients in our ICU. CONCLUSIONS: The processed EEG is able to continuously monitor the end result of some therapeutics at the neuronal level when natural artifacts are suppressed or eliminated by neuromuscular blockade. Computer processed EEG monitoring may be the only objective method of assessing and controlling sedation during therapeutic musculoskeletal paralysis.

Neuromuscular blocking agents in the emergency department

Neuromuscular blocking agents (NMBAs) are utilized frequently in the emergency department (ED). We begin with a brief history of neuromuscular blockade, then review the indications and guidelines for its use in the emergency department setting. The relevant agents will be discussed focusing on dosage, side effects, and adverse reactions. Special attention will be paid to succinylcholine, the drug most commonly employed in the ED setting, followed by a summary of the nondepolarizing agents currently available, in particular the four shorter-acting agents that are most appropriate for administration in the ED.

Lack of a hyperkalemic response in emergency department patients receiving succinylcholine

OBJECTIVE

To determine whether serum potassium (K) levels increase significantly following succinylcholine (SCh)-assisted intubation in ED patients.

METHODS

A prospective, noncontrolled, consecutive case series design was used to evaluate the change in serum K levels in ED patients who received SCh for emergency intubation. The study was performed at an academic medical center staffed by board-certified emergency physicians. The subjects were 100 consecutive prescreened ED patients with various diagnoses who received SCh for intubation. The eligible subjects had serum K levels determined prior to and 5 minutes after administration of a 1.0-1.5-mg/kg i.v. dose of SCh. Serum K levels were measured by the ion-selective electrode assay method.

RESULTS

The mean change in serum K levels was -0.04 mmol/L (95% CI -0.14 to 0.06). The maximum increase was 1.10 mmol/L. The serum K level rose in 46 cases, decreased in 46 cases, and was unchanged in eight cases. No instance of SCh-induced cardiac arrest was identified.

CONCLUSION

Changes in serum K levels following SCh administration in prescreened ED patients were minimal. A hyperkalemic response is uncommon in ED patients who undergo SCh-assisted intubation.

Rapid sequence intubation in the emergency department

Rapid sequence intubation (RSI) has recently gained wide acceptance among emergency physicians (EP). The debate regarding the safety of neuromuscular blocking (NMB) agents in the hands of EPs nonetheless remains open, as objective studies are few, and all data available so far come from tertiary care centers. This retrospective study was done to review our experience with RSI and assess the related morbidity and mortality. Two hundred and nineteen intubations were done using an RSI protocol during the study period. Hypotension occurred in 24 patients. Two patients had a short run of bigeminy and 3 had bradycardia. One patient went into cardiac arrest unrelated to the use of a NMB agent. Aspiration was documented in 3 patients. All patients were successfully intubated. No mortality was attributed to the use of muscle relaxants. Our results support the safety and effectiveness of RSI in the hands of emergency physicians.

Neuromuscular blockade provides no benefit over adequate sedation in ventilated dogs

PURPOSE

To investigate the effect of pharmacological paralysis on systemic oxygen consumption to determine whether pharmacological paralysis offers a physiological benefit over adequate sedation in ventilated animals.

METHODS

Nine dogs with normal pulmonary function were mechanically ventilated and sedated with alpha-chloralose while paralysis was induced with vecuronium. Oxygen consumption was determined via indirect calorimeter in each animal repeatedly in the presence or absence of paralysis with seven paired observations in each animal. Sixty-three pairs of data from nine animals were analyzed by analysis of variance with correction for multiple comparisons.

RESULTS

Oxygen consumption was 4.3% higher in the unblocked state compared with the blocked state (5.39 +/- 0.32 v 5.16 +/- 0.34 mL/kg-min, P < .001). Carbon dioxide production was 3.0% higher in the unblocked state compared with the blocked state (4.92 +/- 0.24 v 4.77 +/- 0.23 mL/kg-min, P < .01). No other physiological effects were noted.

CONCLUSIONS

Pharmacological paralysis of mechanically ventilated animals with normal pulmonary function that are sedated and resting comfortably produces a statistically significant reduction in oxygen consumption; however, the magnitude of this change is so small that little genuine clinical benefit would be anticipated.

Emergency intubation of the pediatric medical patient: use of anesthetic agents in the emergency department

STUDY OBJECTIVES

To delineate the diagnoses of children who required emergency intubation, to ascertain which medications were used, and to describe the complications of intubation and their association with the choice of medications. DESIGN, SETTING, AND TYPE OF PARTICIPANTS: Three-year retrospective study of 60 intubations of critically ill pediatric patients by pediatric emergency physicians in the emergency department setting.

MEASUREMENTS AND MAIN RESULTS

Clinical complications were noted for intubations with neuromuscular paralysis and intubations initially attempted without a paralyzing agent. Intubations attempted without neuromuscular paralysis resulted in a higher rate of complications (53% versus 26%) and a greater risk of more than one complication per intubation. This finding appeared to be independent of physicians' clinical experience.

CONCLUSION

Rapid-sequence protocols with paralysis facilitate intubations in the complex pediatric patient in the ED setting.

Intubation techniques in the helicopter

The purpose of this study is an analysis of 630 field intubations of trauma patients by flight personnel of the San Diego Life Flight program. We compared nasotracheal intubation to rapid sequence induction orotracheal intubation and noninduced orotracheal intubation. We measured success of intubation route, complications, and overall patient outcome. Flight records, quality assurance flight procedure data, and hospitalization data from the San Diego Trauma Registry were reviewed over a 4-year period, from 1988 to 1991. The results of our study show that rapid sequence induction orotracheal intubation has a higher success rate, fewer complications, and a better patient outcome compared to noninduced orotracheal intubation and blind nasotracheal intubation. We recommend that rapid sequence induction oral intubation be the standard method for prehospital airway management in trauma patients.

Airway control in trauma patients with cervical spine fractures

INTRODUCTION

Proper airway control in trauma patients who have sustained cervical spine fracture remains controversial.

PURPOSE

This study was undertaken to survey the preferred methods of airway management in cervical spine fracture (CSF) patients, to evaluate the experience of handling such patients at a level-I trauma center, and to contrast the findings with recommendations of the American College of Surgeons Committee on Trauma.

HYPOTHESIS

The methods used for control of the airway in patients with fractures of their cervical spine support the recommendation of the American College of Surgeons (ACS) Committee on Trauma.

METHODS

The study consisted of two parts: 1) a survey; and 2) a retrospective study. Survey questionnaires were sent to 199 members of the Eastern Association for the Surgery of Trauma and to 161 anesthesiology training programs throughout the United States. Three resuscitation scenarios were posed: 1) Elective airway--CSF--breathing spontaneously, stable vital signs; 2) Urgent airway--CSF--breathing spontaneously, unstable vital signs; and 3) Emergent airway--CSF--apneic, unstable. In addition, a three-year retrospective study was conducted at a level-I trauma center to determine the method of airway control in patients with cervical spine fractures.

RESULTS

Responses to the questionnaires were received from 101 trauma surgeons (TS) and 58 anesthesiologists (ANESTH). Respondents indicated their preference of airway methods: Elective airway: Nasotracheal intubation: TS 69%, ANESTH 53%. Orotracheal intubation: TS and ANESTH 27%. Surgical airway: TS 4%. Intubation with fiberoptic bronchoscope (FOB): ANESTH 20%. Urgent airway: Nasotracheal intubation: TS 48%, ANESTH 38%. Orotracheal intubation: TS 47%, ANESTH 45%. Surgical airway: TS 4%. FOB: ANESTH 16%. Emergent airway: Orotracheal intubation: TS 81%, ANESTH 78%. Surgical Airway: TS 19%, ANESTH 7%. FOB: ANESTH 15%. The retrospective review at the trauma center indicated that 102 patients with CSF were admitted; 62 required intubation: four (6%) on the scene, seven (11%) en route, five (8%) in the emergency department, 42 (67%) in the operating room, and four (6%) on the general surgery floor. Airway control methods used were nasotracheal: 14 (22%); orotracheal: 27 (43%); FOB: 17 (27%); tracheostomy: one (2%); unknown: three (4%). No progression of the neurological status resulted from intubation.

CONCLUSION

The choice of airway control in the trauma patient with CSF differs between anesthesiologists and surgeons. However, the method selected does not have an adverse affect on neurological status as long as in-line stabilization is maintained. The methods available are safe, effective, and acceptable. The recommendations of the American College of Surgeons Committee on Trauma for airway control with suspected cervical spine injury are useful. The technique utilized is dependent upon the judgment and experience of the intubator.

Emergency management of the airway outside the operating room

Successful emergency airway intervention incorporates the anaesthetist's basic skills in airway management with the knowledge of the special nature of the clinical problems that arise outside the operating room. While a thorough but rapid evaluation of the key anatomical and physiological factors of an individual patient may result in an obvious choice for optimal management, clinical problems often arise in which there is not an evident "best approach." In these less clear-cut situations, the anaesthetist may do well to employ those techniques with which she/he has the greatest skills and experience. At times, however, some degree of creative improvisation is required to care for an especially difficult problem.

Neuromuscular blockade in aeromedical airway management

STUDY OBJECTIVE

Induction of paralysis before intubation is controversial in the aeromedical setting. We reviewed our experience using neuromuscular blockade with nurse/paramedic aeromedical teams to determine effectiveness and outcome.

MATERIALS AND METHODS

In 670 flights during a 16-month period, 119 patients required endotracheal intubation aided by muscle relaxant administration. Age ranged from two months to 83 years, with a mean of 33 years. All patients were hyperventilated with 100% oxygen before intubation. Sedation was given if presenting systolic blood pressure was greater than 100 mm Hg. A short-acting depolarizing agent was then given in a 1-mg/kg dose. Once the airway was secure, a longer-acting, nondepolarizing agent and/or sedation was given.

RESULTS

Of the 119 patients, 115 (96.6%) were orally intubated. Four (3.4%) required surgical airway intervention because of injuries and conditions prohibiting oral intubation. Of 115 oral intubations, 99 (86%) were achieved on the first attempt. Eight patients (7%) were intubated on a second attempt, and another eight were intubated on a third attempt. There was no change in operator. Sixty-eight percent of patients requiring airway management were multiple trauma victims with associated head injuries. There were no laryngeal injuries, detected cardiac rhythm changes, bleeding episodes, or neurologic complications despite incomplete cervical-spine evaluation.

CONCLUSION

Neuromuscular blockade can be used safely and effectively in the field by experienced nurse/paramedic teams. Although problematic intubation was not eliminated, the difficulties encountered were manageable and the overall risk/benefit ratio was acceptable.

Air medical tracheal intubation: establishing a threshold for this QA indicator

Endotracheal intubation is a critical skill necessary in a number of situations encountered by air medical personnel. The purpose of this study was to establish a threshold for the quality assurance indicator of successful tracheal intubation in a physician-staffed air medical system. The records of all patients transported by a physician-staffed air medical system over a 36-month period were reviewed. One hundred and forty-three patients had endotracheal intubation attempted. Blind nasotracheal intubation attempts were successful in 71% of those in whom it was attempted, while the overall intubation success rate was 92%. Based on this study and the existing literature, a threshold of 90% is recommended for the quality assurance indicator of successful tracheal intubation in physician-staffed air medical systems.

Emergency intubation for paralysis of the uncooperative trauma patient

The impact of paralysis followed by intubation was studied in patients who had been traumatized and subsequently admitted to Lehigh Valley Hospital Center. Trauma admission records between January 1987 and June 1988 were reviewed. Fifty-seven patients, intubated for control of agitation and combativeness, were divided into high injury severity (HIS) and low injury severity (LIS) subgroups using admission trauma (TS) and injury severity scores (ISS). Thirty-eight (70%) were classified as HIS and 19 (30%) as LIS. All HIS patients had significant injuries diagnosed following paralysis with intubation (PWI). Mortality in the HIS group was 9%. The LIS subgroup was compared to a randomly selected group of similarly injured blunt trauma patients who did not require PWI. There were significant differences (P less than 0.05) in age, hospital cost, hours per day of nursing care, and percent of patients with an ETOH level greater than 100 mg%. Emergency paralysis with intubation is an effective method for controlling the uncooperative, combative, seriously injured patient. However, patients with low injury severity who require restraint have higher costs and require more care if they are paralyzed and intubated than if they are not.

Prehospital blind nasotracheal intubation by paramedics

Blind nasotracheal intubation attempts by paramedics in the field were prospectively reviewed. In particular, we analyzed the frequency, success rate, complication rate, frequency of performance by each paramedic, indications, and patient outcome. Blind nasotracheal intubation was attempted in 324 patients and successful in 231. The average success rate for medical patients was 72.2% (195 of 270 attempts) and for trauma patients was 66.7% (36 of 54 attempts). This difference was not significant (P greater than .05). Even with 59.8% of the 82 participating paramedics attempting blind nasotracheal intubation less than four times over the 19-month study period, the average success rate was 71.3%. There was a significant increase in success when blind nasotracheal intubation was attempted more than three times during the study period (P less than .005). Major complications occurred in 0.9% (three) of the patients. The overall complication rate was 13% (42). The incidence of complications tended to decline with increasing paramedic frequency but did not reach statistical significance (P greater than .05). Blind nasotracheal intubation is a safe initial field airway approach in spontaneously breathing patients in whom there are no contraindications. Even with a low frequency of performance, success and complication rates are acceptable.

Cricothyrotomy in the emergency department revisited

Thirty-nine emergency cricothyrotomies were reviewed from the emergency department of Hennepin County Medical Center during the 4-year period ending December 1985. Due to technical changes in airway management and a desire to assess their impact, this experience was compared with a previously reported series of 38 emergency cricothyrotomies from the same department. Technical changes include the use of paralyzing agents, transtracheal needle ventilation, and the use of only vertical skin incisions and #4 Shiley tubes when cricothyrotomy is performed. The presenting problem, indications for cricothyrotomy and complications of the procedure were compared between the two series. Fewer cricothyrotomies were done as a fraction of total surgical and nonsurgical tracheal intubations in the present series (1.7%) compared to the previous series (2.7%). The complication rate decreased from 40% in the previous series to 23% in the present series. Incorrect site of tube placement (10%) and hemorrhage (8%) remain the two leading complications. However, the tube was in the trachea in all cases, and acceptable ventilation was achieved. No patient developed a clinically significant hematoma or hemorrhage from cricothyrotomy. It is concluded that our technical changes in airway management have helped to decrease both the relative frequency of cricothyrotomy and the complication rate.

Evaluating anatomical factors affecting endotracheal intubation

Critically ill patients often require endotracheal intubation in the emergency department. Sometimes immediate attempts at endotracheal intubation are indicated. In other situations, a momentary delay to assess the anatomic factors that might make intubation difficult is advantageous. This examination should include assessment of nose and oral cavity patency, mobility and posterior depth of the mandible, and mobility and length of the neck.

Prehospital use of neuromuscular blocking agents in a helicopter ambulance program

We prospectively studied the use of succinylcholine chloride and pancuronium bromide by the physician/nurse flight team of our hospital-based helicopter ambulance service. Patients who received these agents at the scene of an accident (prehospital group, n = 39) were compared with patients who were paralyzed by the flight team in the emergency department of transferring hospitals (control group, n = 35). By protocol, succinylcholine was used primarily for endotracheal intubation and pancuronium for prolonged paralysis after endotracheal intubation. Seventy-four patients received one or both agents. Overall, 61 of 74 patients had intracranial pathology as their primary diagnosis (82%). Endotracheal intubation was the primary indication for paralysis in the majority of patients (67 of 74), although intracranial pressure control, ventilation, agitation control, and seizure control were frequent secondary indications. Prior intubation attempts had failed in 40 of 74 patients (54%). After paralysis, intubation was successful in 68 of 71 patients (96%). Serious complications (ie, dysrhythmia requiring drug therapy) occurred in three patients but resolved with appropriate therapy in each case. Minor complications (ie, dysrhythmia not requiring drug therapy, histamine flush, infiltrated IV line) occurred in 18 patients. There was no significant difference in successful intubation or complication rate between the prehospital and control group. Paralysis allowed airway stabilization in a significant number of critically ill patients who could not otherwise be endotracheally intubated, with a lower incidence of complications than has been previously reported for ED patients. These results suggest that neuromuscular blocking agents can be used safely and effectively at accident scenes by a physician/nurse team.