Chest Ultrasonography for the Diagnosis and Monitoring of High-Altitude Pulmonary Edema

BACKGROUND

The comet-tail technique of chest ultrasonography has been described for the diagnosis of cardiogenic pulmonary edema. This is the first report describing its use for the diagnosis and monitoring of high-altitude pulmonary edema (HAPE), the leading cause of death from altitude illness.

METHODS

Eleven consecutive patients presenting to the Himalayan Rescue Association clinic in Pheriche, Nepal (4,240 m) with a clinical diagnosis of HAPE underwent one to three chest ultrasound examinations using the comet-tail technique to determine the presence of extravascular lung water (EVLW). Seven patients with no evidence of HAPE or other altitude illness served as control subjects. All examinations were read by a blinded observer.

RESULTS

HAPE patients had higher comet-tail score (CTS) [mean +/- SD, 31 +/- 11 vs 0.86 +/- 0.83] and lower oxygen saturation (O(2)Sat) [61 +/- 9.2% vs 87 +/- 2.8%] than control subjects (p < 0.001 for both). Mean CTS was higher (35 +/- 11 vs 12 +/- 6.8, p < 0.001) and O(2)Sat was lower (60 +/- 11% vs 84 +/- 1.6%, p = 0.002) at hospital admission than at discharge for the HAPE patients with follow-up ultrasound examinations. Regression analysis showed CTS was predictive of O(2)Sat (p < 0.001), and for every 1-point increase in CTS O(2)Sat fell by 0.67% (95% confidence interval, 0.41 to 0.93%, p < 0.001).

CONCLUSIONS

The comet-tail technique effectively recognizes and monitors the degree of pulmonary edema in HAPE. Reduction in CTS parallels improved oxygenation and clinical status in HAPE. The feasibility of this technique in remote locations and rapid correlation with changes in EVLW make it a valuable research tool.

What happens to SpO2 during air medical crew intubations?

OBJECTIVES

Studies finding adverse outcomes associated with emergency medical services intubation (ETI) have prompted recommendations for prehospital services to improve tracking of oxygenation during airway management. Our goals were to 1) implement a documentation requirement for helicopter EMS (HEMS) crews, entailing tracking and notation of the lowest SpO2 value (peri-ETI SpO2 nadir) occurring during HEMS crew ETI, and 2) assess the findings associated with the peri-ETI SpO2 documentation parameter.

METHODS

This was a prospective study conducted at an urban HEMS program with flight nurse/flight paramedic staffing and protocol-driven care. There were 200 consecutive cases undergoing HEMS ETI between April 2004 and July 2005. Univariate logistic regression with odds ratio (OR) was used to assess for association between ETI-related hypoxemia (decrease in SpO2 value to < 90% during ETI) and patient/intubator characteristics.

RESULTS

HEMS crew ETI was successful in 189 (95.4%) of the 200 patients. The lowest peri-ETI SpO2 value was specifically documented in 170 patients (85%) in the study group. In univariate analysis, successful crew ETI was correlated with avoidance of crew-recorded SpO2 value decreasing to < 90% (OR, 0.23; 95% confidence interval, 0.07-0.83). Similarly, requirement for multiple attempts at ETI was correlated with higher likelihood that crews recorded peri-ETI SpO2 value decreasing to < 90% (OR, 7.8; 95% confidence interval, 3.2-18.8). However, in nearly two thirds of cases in which multiple attempts were executed, the peri-ETI SpO2 value remained > 90%. Of the seven patients in whom rescue laryngeal mask airways were placed, the peri-ETI SpO2 value remained > 90% in three (42.9%).

CONCLUSION

Documentation of crew-recorded peri-ETI SpO2 nadir is a useful and practical prehospital data point.

Prehospital electrocardiogram and early helicopter dispatch to expedite interfacility transfer for percutaneous coronary intervention

Care provision and benchmarking for patients with ST-elevation myocardial infarction (STEMI) have focused on streamlining time between initial hospital presentation and opening of theinfarct-related artery. In a Boston-area regional system already characterized by expedited advanced life support (ALS) dispatch and paramedic performance of prehospital electrocardiogram (EKG), a critical pathway was designed that allows for helicopter dispatch based on ground ALS providers' STEMI diagnosis. The pathway dictates that as soon as ALS crews make the diagnosis of STEMI from their 12-lead EKG, they will contact Boston MedFlight (BMF) and a helicopter will be immediately dispatched to the participating community hospital (Lawrence General Hospital [LGH]). Based on historical and predicted time patterns, it is expected that BMF will arrive at LGH soon after the ALS ambulance delivers the patient to the LGH emergency department (ED). The patient will then undergo BMF transport from the ED into central Boston with direct transfer into an awaiting cardiac catheterization suite (ie, bypassing the receiving hospital ED). The pathway minimizes the delay between patient arrival at LGH and BMF arrival for transport to the catheterization laboratory. It is hoped that implementation of the critical pathway will allow the region's patients with STEMI to achieve coronary arterial patency within 90 minutes of LGH presentation. If the pathway proves effective, it can serve as a model for other regions and programs with similar clinical and logistic situations and advance the concept of "diagnosis-to-balloon" time.

Report of the Task Force on National Fourth Year Medical Student Emergency Medicine Curriculum Guide

This manuscript reports recommendations of the National Fourth Year Medical Student Emergency Medicine Curriculum Guide Task Force. This task force was convened by 6 major emergency medicine organizations to develop a standardized curriculum for fourth year medical students. The structure of the curriculum is based on clerkship curricula from other specialties such as internal medicine and pediatrics. The report contains a historical context, global and targeted needs assessment, goals and objectives, recommended educational strategies, implementation guidelines, and suggestions on feedback and evaluation.

Timing of Fresh Frozen Plasma Administration and Rapid Correction of Coagulopathy in Warfarin-Related Intracerebral Hemorrhage

Background and Purpose— Anticoagulation-related intracerebral hemorrhage (ICH) is often fatal, and rapid reversal of anticoagulation is the most appealing strategy currently available for treatment. We sought to determine whether particular emergency department (ED) interventions are effective in reversing coagulopathy and improving outcome.

Methods— Consecutive patients with warfarin-related ICH presenting to an urban tertiary care hospital from 1998 to 2004 were prospectively captured in a database. ED records were retrospectively reviewed for dose and timing of fresh-frozen plasma (FFP) and vitamin K, as well as serial coagulation measures. After excluding patients with incomplete ED records, do-not-resuscitate orders established in the ED, initial international normalized ratio (INR) ≤1.4, and for whom no repeat INR was performed, 69 patients were available for analysis. The primary outcome was a documented INR ≤1.4 within 24 hours of ED presentation.

Results— Patients whose INR was successfully reversed within 24 hours had a shorter median time from diagnosis to first dose of FFP (90 minutes versus 210 minutes; P =0.02). In multivariable analysis, shorter time to vitamin K, as well as FFP, predicted INR correction. Every 30 minutes of delay in the first dose of FFP was associated with a 20% decreased odds of INR reversal within 24 hours (odds ratio, 0.8; 95% CI, 0.63 to 0.99). Dosing of FFP and vitamin K had no effect. No ED intervention was associated with improved clinical outcome.

Conclusions— Time to treatment is the most important determinant of 24-hour anticoagulation reversal. Although additional study is required to determine the clinical benefit of rapid reversal of anticoagulation, minimizing delays in FFP administration is a prudent first step in emergency management of warfarin-related ICH.

Fentanyl trauma analgesia use in air medical scene transports

This study assessed frequency, safety and efficacy of prehospital fentanyl analgesia during 6 months' adult and pediatric helicopter trauma scene transports (213 doses in 177 patients). We reviewed flight records for pain assessment and analgesia provision, effect, and complications. Analgesia was administered to 46/49 (93.9%) intubated patients. In non-intubated patients, pain assessment was documented in 112 of 128 (87.5%), and analgesia was offered, or there was no pain, in 97/128 (75.8%). Of the 67 non-intubated patients to whom analgesia was administered, post-analgesia pain assessment was documented in 62 (92.5%) and pain improved in 53 (79.1% of 67). Post-analgesia blood pressure dropped below 90 torr in 2/177 cases (1.1%, 95% confidence interval [CI] 0.1-4.0%). Post-analgesia S(p)O(2) did not drop below 90% in any patients (95% CI 0-2.3%). In this study, prehospital providers performed well with respect to pain assessment and treatment. Fentanyl was provided frequently, with good effect and minimal cardiorespiratory consequence.

Opioid analgesia and assessment of the sonographic Murphy sign

Administration of intravenous opioid analgesia to patients with undifferentiated abdominal pain remains a controversial topic in many emergency departments. To determine whether opioid analgesia impacts assessment of the sonographic Murphy sign (SM) in evaluating acute gallbladder disease (GBD), a retrospective chart review was undertaken. The chart review encompassed 119 patients, 21% of whom, having received opioid analgesia before ultrasound, constituted the opioid group. Between the opioid and control (i.e., no opioid analgesia) groups, there were no significant differences in SM sensitivity (48.2%; CI 28.7-68.1% vs. 68.8%; CI 41.3-89%, respectively) or specificity (92.5%; CI 83.4-97.5% vs. 88.9%; CI 51.8-99.7%, respectively) for GBD. There was no association between opioid analgesia and false-positive SM (OR 0.74, CI 0.08-6.65), or false-negative SM (OR 1.42, CI 0.46-4.43). We conclude that the test characteristics of SM are unaffected by opioid analgesia.

Creation of an online collection of emergency medicine literature

Residents and medical students are challenged to incorporate the latest medical literature into their clinical practice. However, retrieving influential articles in a timely manner can be difficult. To address this, the authors created a collection of influential primary research literature relevant to the practice of emergency medicine. The authors surveyed local experts as to the most influential articles in their area of expertise and then linked articles in the literature collection to full-text versions available through the medical school's digital library. A total of 154 articles were included in the literature collection. These were organized into 23 subject headings and 23 subheadings. Fifty-two residents were surveyed one month after the collection became available; 18 residents (35%) had used the literature collection at that time. An online collection has several advantages: it makes the most relevant literature immediately available during clinical care and allows residents to elaborate on their own knowledge when clinical problems arise. It also can be easily updated and password protected. Similar collections may be developed for use in other educational settings.

Inadequate hemodynamic management in patients undergoing interfacility transfer for suspected aortic dissection

The study goal was the analysis of effectiveness of hemodynamic management of patients undergoing interfacility transport for suspected acute aortic dissection (SAAD). Our retrospective, consecutive-case review examined 62 nonhypotensive patients transported by an air emergency medical services (EMS) service during 1998 to 2002, with referral hospital diagnosis of SAAD. Of patients with systolic blood pressure (SBP) less than 120 upon air EMS arrival, antihypertensives had been given in only 23/42 (54.8%). In 19 cases where pretransport SBP is less than 120, with no referral hospital antihypertensive therapy given, median pretransport SBP was 158 (range, 122-212). In 20/62 cases (32.3%), the air EMS agency instituted antihypertensive therapy, which was successful; of 42 cases with pretransport SBP less than 120, mean intratransport SBP decrement was 24 (95% confidence interval, 16-32). In patients undergoing transport for SAAD, pretransport hemodynamic therapy was frequently omitted and often inadequate, generating an opportunity for air EMS intervention. Education to improve SAAD care should focus upon both referral hospitals and transport services.

Use of a radial artery compression device for noninvasive, near-continuous blood pressure monitoring in the ED

This study's goal was to test a novel device using continuous partial radial artery compression for mean arterial pressure (MAP) measurement. A prospective, nonblind, convenience-sample trial at a level I center (annual ED census 70,000) enrolled 15 adults with indwelling radial arterial catheters and accessible contralateral radial pulse. Subjects had MAPs measured simultaneously by test device (TEST assessments), oscillometric brachial artery cuff (OSC), and arterial line (ART). There was no difference between the three groups' MAP means (P = .98). R(2) values for ART/OSC and ART/TEST were 0.96 and 0.95, respectively (P <.001). TEST and OSC MAP readings were equally likely (P = 0.66) to be within 5 mm Hg of ART in both the overall set of 307 MAPs and in the subset of 120 cases in which ART MAPs were below 80 (P = .47). The TEST device performed at least as well as oscillometric assessment, offering advantages of noninvasive, near-continuous data.

Helicopter emergency medical services transport outcomes literature: annotated review of articles published 2000-2003

Helicopter emergency medical services (HEMS) and its possible association with outcomes improvement continues to be a subject of debate. As is the case with other scientific endeavors, debate over HEMS usefulness should be framed around an evidence-based assessment of the relevant literature. In an effort to facilitate the academic pursuit of assessment of HEMS utility, in late 2000 the National Association of EMS Physicians' Air Medical Committee prepared annotated bibliographies of the HEMS-related outcomes literature. As a result of that work, two review articles-one covering HEMS use in nontrauma and the other in trauma-published in 2002 in Prehospital Emergency Care surveyed HEMS outcomes-related literature published between 1980 and mid-2000. Given the broad interest in the earlier reviews, and the increasing rate of publication of HEMS studies, the current project was executed with the intent of updating the annotated HEMS outcomes-related bibliography, covering a three-year time interval (through 2003) since the prior reviews.

Utilization of appetite suppressants in England: a putative indicator of poor prescribing practice

The use of appetite suppressants, a putative inverse marker of prescribing quality, was analysed in the former Northern Regional Health Authority (RHA) and in England using National Health Service prescribing data and sales and patient-linked prescribing data supplied by Intercontinental Medical Statistics (IMS). The number (in thousands) of National Health Service prescriptions for appetite suppressants dispensed fell from 393 in 1991 to 235 in 1994. Per capita prescribing frequency varied threefold between different RHA and between individual Family Health Service Authorities (FHSA) within the former Northern RHA (NRHA). Prescribing frequency was higher in the spring and summer quarters and reduced in the winter quarter. Of 532 general practices in the NRHA, 82 (15%) prescribed no appetite suppressants between April 1993 and March 1994, while 70 (13%) prescribed more than 500 defined daily doses (DDDs) per 1000 patients, accounting for 47% of all prescribing. Only 53% of pharmacy purchases of appetite suppressants were accounted for by NHS prescribing and as little as 21% for phentermine, indicating substantial prescribing outwith the NHS. In 1991, 73,759 DDDs were supplied to pharmacies each day, the majority being diethylpropion (31,226) and phentermine (24,349). The fall in NHS prescribing is welcome as these drugs are of dubious clinical value and may be associated with serious adverse effects. Because of substantial non-NHS prescribing, routinely available prescribing data does not accurately quantify total prescribing of these agents.

Cyperus Tubers Protect Meloidogyne incognita from 1,3-Dichloropropene

Meloidogyne incognita-infected and noninfected tubers of yellow nutsedge (Cyperus esculentus) and purple nutsedge (Cyperus rotundus) were treated with 56 L/ha 1,3-dichloropropene (1,3-D) in microplots and subsequently examined for tuber and nematode viability in the greenhouse using a chile pepper (Capsicum annuum) bioassay system. The study was conducted three times. Nutsedge tuber viability and M. incognita harbored in both yellow and purple nutsedge tubers were unaffected by 1,3-D treatment. Nematode reproduction on nutsedges and associated chile pepper plants varied among years, possibly due to differing levels of tuber infection or soil temperature, but was not affected by fumigation. The presence of M. incognita resulted in greater yellow nutsedge tuber germination and reproduction. The efficacy of 1,3-D for management of M. incognita in chile pepper production is likely to be reduced when nutsedges are present in high numbers, reinforcing the importance of managing these weeds and nematodes simultaneously.

Ongoing visual analog score display improves Emergency Department pain care

The study purpose was to test two methods of pain assessment and display: ongoing (11 times over 2 h) visual analog scale (VAS) determination with data tabulation in the ED chart (Tabulation group), and similar VAS assessments with display of the information at the head of the ED bed (Graph group). A Control group had initial and 2-h VAS ascertainments charted (not graphed). Tertiary-care university-affiliated ED patients were randomized into the three groups and pain care outcomes assessed. Compared to Controls, those in the Graph group had the following findings (p < 0.05): 1) treating physicians more likely aware of initial and final VAS scores, 2) earlier analgesia, 3) likelier perception (by patients and physicians) that VAS was useful and likelier patient perception that pain care was adequate. Tabulation group results were intermediate to those of Control and Graph patients. The data support further investigation of VAS display as a means of improving ED pain assessment.

The 2003 Air Medical Leadership Congress: findings and recommendations

To address important concerns facing the air medical community, 149 air medical transport leaders, providers, consultants, and experts met September 4-6, 2003, in Salt Lake City, Utah, for a 3-day summit-the Air Medical Leadership Congress: Setting the Health Care Agenda for the Air Medical Community. Using data from a Web-based survey, top air medical transport issues were identified in four core areas: safety, medical care, cost/benefit, and regulatory/compliance. This report reviews the findings of previous congresses and summarizes the discussions, findings, recommendations, and proposed industry actions to address these issues as set forth by the 2003 congress participants.

Success rates of pediatric intubation by a non-physician-staffed critical care transport service

OBJECTIVES

Previous researchers have found that institution of an endotracheal intubation (ETI) protocol into a large urban paramedic program resulted in low success rates and had no beneficial effects. The primary goal of the current study was to assess ETI success rates achieved by a small cadre of nonphysician critical care transport (CCT) providers. A secondary objective was to assess for association between ETI success and factors such as age group or ETI setting (eg, in-hospital, in-aircraft).

DESIGN

This retrospective study analyzed transport records of consecutive pediatric patients (younger than 13 years) in whom ETI was attempted by a nurse/paramedic (RN/EMTP) CCT crew working under protocols which included neuromuscular blockade (NMB)-facilitated ETI. The CCT service performs scene and interfacility transports in helicopter, fixed-wing (airplane), and ground critical care vehicles; pediatric patients are transferred to 4 receiving tertiary care centers. Chi2 test, Fisher exact test, and logistic regression analysis (P = 0.05) examined ETI success rates and assessed for association between ETI success and various characteristics (eg, age group, ETI setting).

RESULTS

The CCT crew attempted ETI in 143 patients, with success in 136 cases (95.1%). There were no unrecognized esophageal intubations. ETI success was of similar likelihood across pediatric age groups (P = 0.19) and in different ETI settings (P = 0.57).

CONCLUSIONS

CCT crew airway management success was very high in all practice settings. These data support contentions that, with a high level of initial and ongoing training, nonphysician CCT crew can successfully manage pediatric airways in a variety of circumstances.

The Air Medical Leadership Congress: setting the health care agenda for the air medical community

BACKGROUND

Emergency air medical transport provides the means for critically ill or injured patients to rapidly access sophisticated medical flight teams and medical centers. However, issues such as surging emergency medical services helicopter accidents, expected pilot and nurse shortages, falling reimbursements, and new compliance regulations are now threatening these important but expensive transport services. Unless an industry strategy can be developed to address these and other threats, many medical flight programs may be forced to curtail the availability of these lifesaving services.

PURPOSE

On September 4-6, 2003, air medical leaders, experts, program managers, providers, and users of emergency air medical services gathered in Salt Lake City, Utah, to discuss and formulate recommendations to address the top issues that threaten the future of air medical transport services. This congress was open to anyone engaged in the field of air medical transport. This historic meeting resulted in a plan to enhance transport safety, foster appropriate utilization, improve in-flight medical care, maximize cost and reimbursement effectiveness, and develop strategies to reduce the adverse effects of new regulatory and compliance mandates.

OBJECTIVES

This article describes the significance of the Air Medical Leadership Congress and the 10-Point Plan method used to develop it.

Isolated prehospital hypotension after traumatic injuries: a predictor of mortality?

In patients with traumatic injuries, prehospital hypotension that resolves by Emergency Department (ED) arrival is of uncertain significance. We examined the impact of prehospital hypotension (PH) in normotensive ED patients with traumatic injuries on predicting mortality and chest/abdominal operative intervention. A retrospective cohort study was conducted of consecutive patients undergoing helicopter transport to two trauma centers between 1993 and 1997. Outcomes were mortality and chest or abdominal operative intervention. Of 545 scene transports, 55 (10.1%) patients were hypotensive on ED arrival, leaving 490 normotensive ED patients. Of 490 patients, 35 (7%) had PH and 455 (93%) had no PH. Multiple logistic regression showed the PH group to have a relative risk for death of 4.4 (95% CI: 1.2-16.6, p < 0.03) and for chest or abdominal operative intervention of 2.9 (1.1-7.6, p < 0.03). In this study of normotensive trauma center patients, prehospital hypotension was associated with increased risk of mortality and significant chest or abdominal injury.

High altitude headache: efficacy of acetaminophen vs. ibuprofen in a randomized, controlled trial

Ibuprofen has been shown to be more effective than placebo in the treatment of high altitude headache (HAH), but nonsteroidal anti-inflammatory agents have been linked to increased incidence of gastrointestinal (GI) side effects and high-altitude pulmonary edema (HAPE). We postulated that acetaminophen, which does not share ibuprofen's theorized causal link to GI side effects or HAPE, could provide effective HAH therapy. We conducted a prospective, randomized, double-blind, clinical trial of ibuprofen vs. acetaminophen in the Solu Khumbu, Nepal: Mt. Everest Base Camp, Pheriche, Dingboche (4240 m to 5315 m). Seventy-four consecutive patients (ages 13 to 61 years) were randomized, were assessed with the Lake Louise Acute Mountain Sickness (AMS) criteria, and received a physical examination (which included vital signs, oxygen saturation as measured by pulse oximetry (SpO(2)), and assessment of clinical Lake Louise AMS criteria). Patients then received either 400 mg of ibuprofen (IBU) or 1000 mg of acetaminophen (ACET), and were asked to rate their cephalgia using a 10-cm visual analog scale (VAS). Thirty-nine patients received IBU, and 35 received ACET. Baseline Lake Louise AMS scores were identical in the two groups (mean = 5.9). No differences in mean VAS scores between IBU and ACET groups were noted at time 0 (presentation), 30, 60, or 120 min. No cases of HAPE or high altitude cerebral edema were noted during the study period. In this study population, acetaminophen was as effective as ibuprofen in relieving the pain of HAH.