Patrick C. Drayna

Near-infrared spectroscopy in the critical setting.

Near-infrared spectroscopy is a noninvasive means of determining real-time changes in regional oxygen saturation of cerebral and somatic tissues. Hypoxic neurologic injuries not only involve devastating effects on patients and their families but also increase health care costs to the society. At present, monitors of cerebral function such as electroencephalograms, transcranial Doppler, jugular bulb mixed venous oximetry, and brain tissue oxygenation monitoring involve an invasive procedure, are operator-dependent, and/or lack the sensitivity required to identify patients at risk for cerebral hypoxia. Although 20th century advances in the understanding and management of resuscitation of critically ill and injured children have focused on global parameters (ie, pulse oximetry, capnography, base deficit, lactate, etc), a growing body of evidence now points to regional disturbances in microcirculation that will lead us in a new direction of adjunctive tissue monitoring and response to resuscitation. In the coming years, near-infrared spectroscopy will be accepted as a way for clinicians to more quickly and noninvasively identify patients with altered levels of cerebral and/or somatic tissue oxygenation and, in conjunction with global physiologic parameters, guide efficient and effective resuscitation to improve outcomes for critically ill and injured pediatric patients.

Ketamine sedation is not associated with clinically meaningful elevation of intraocular pressure

BACKGROUND Ketamine is widely used for procedural sedation, but there is limited knowledge on whether ketamine use is associated with elevated intraocular pressure (IOP). OBJECTIVE The aim of this study was to examine whether there are clinically important elevations of IOP associated with ketamine use during pediatric procedural sedation. METHODS We prospectively enrolled children without ocular abnormalities undergoing procedural sedation that included ketamine for nonperiorbital injuries. We measured IOP for each eye before and at 1, 3, 5, 15, and 30 minutes after initial intravenous ketamine administration. We performed Bland-Altman plots to determine if IOP measurements in both eyes were in agreement. Linear regression was used to model the mean IOP of both eyes as a function of time, dose, and age, with a robust sandwich estimator to account for repeated measures. RESULTS Among 25 participants, median (interquartile range) age was 11 (9-12) years, and 18 (72%) were male. Median ketamine dose was 1.88 mg/kg (interquartile range, 1.43-2.03 mg/kg; range 0.96-4 mg/kg). Bland-Altman plots demonstrated a mean difference of IOP between eyes near zero at all time points. The largest predicted difference from baseline IOP occurred at 15 minutes, with an estimated change of 1.09 mm Hg (95% confidence interval, -0.37 to 2.55). The association between ketamine dose and mean IOP was not statistically significant or clinically meaningful (P = .90; estimated slope, 0.119 [95% confidence interval, -1.71 to 1.95]). There were no clinically meaningful levels of increased measured average IOP reached at any time point. CONCLUSIONS At dosages of 4 mg/kg or less, there are not clinically meaningful associations of ketamine with elevation of IOP.

Prehospital Pediatric Care: Opportunities for Training, Treatment, and Research

Abstract Objective. Pediatric transports comprise approximately 10% of emergency medical services (EMS) requests for aid, but little is known about the clinical characteristics of pediatric EMS patients and the interventions they receive. Our objective was to describe the pediatric prehospital patient cohort in a large metropolitan EMS system. Methods. This retrospective analysis of all pediatric (age <19 years) EMS patients transported from October 2011 to September 2013 was conducted by reviewing a system-wide National EMS Information System (NEMSIS)-compliant database of all EMS patient encounters. We identified the most common primary working assessments, the frequency of abnormal initial vital signs, and the interventions provided. Vital signs included systolic blood pressure (SBP), respiratory (RR) and pulse rate, Glasgow Coma Scale (GCS), pulse oximetry (Pox), and respiratory effort. We defined abnormal vital signs using previously reported age-specific standards. We identified the working assessments most frequently associated with abnormal vital signs and the working assessments associated with the most commonly performed interventions. Data were analyzed using descriptive statistics. Results. There were 9,956 pediatric transports, 8.7% of the total call volume. The most common working assessments were “other” (16.1%), respiratory distress (13.7%), seizure (12.4%), and blunt trauma (12.0%). Vital signs were documented at variable rates: RR (91.1%), GCS (82.9%), SBP (71.3%), pulse (69.4%), respiratory effort (49.7%), and Pox (33.5%). Of all transported patients, 61.5% had a documented abnormal initial vital sign. Patients with an abnormal vital sign had the same most common working assessments as those with normal vital signs. Glucometry (16.9%), medication delivery (13.6%), and IV placement (11.5%) were the most common interventions and were most often provided to patients with working assessments of seizure, asthma, trauma, altered consciousness, or “other.” Cardiopulmonary resuscitation (0.4%), bag mask ventilation (0.4%), and advanced airway (0.4%) occurred rarely and were most often performed for cardiac arrest and trauma. Conclusions. Children made up a small part of EMS providers’ clinical practice; those encountered most frequently had respiratory distress, seizures, trauma, or an undefined assessment (i.e., “other”). EMS providers frequently encounter children with physiologic evidence of acute illness, although vital sign documentation was incomplete. Prehospital providers infrequently perform pediatric interventions. Describing EMS providers’ interaction with children provides the opportunity to target improvements in pediatric prehospital treatment, training, and research.

A consensus-based criterion standard definition for pediatric patients who needed the highest-level trauma team activation

Background Verbal prehospital reports on an injured patient’s condition are typically used by trauma centers to determine if a trauma team should be present in the emergency department prior to patient arrival (i.e., trauma team activation). Efficacy studies of trauma team activation protocols cannot be conducted without a criterion standard definition for which pediatric patients need a trauma team activation.

Helicopter interfacility transport of pediatric trauma patients: Are we overusing a costly resource?

BACKGROUND Helicopter emergency medical services (HEMS) provide an important service to decrease interfacility transport times compared with ground ambulances. Although transport via HEMS is typically faster, the decreased transportation time comes at the expense of increased risks to the patient and flight crew and higher costs. Therefore, it is important to balance the immediate patient needs with the risk and expense of HEMS transport. Our objective was to determine how frequently pediatric patients who are interfacility transported to a Level 1 pediatric trauma center (PTC) receive a time-sensitive intervention. METHODS This was a 4-year (2008–2012) retrospective study of children aged 0 year to 18 years who were interfacility transported to a single Level 1 PTC by HEMS. Patients were identified using the trauma registry at the PTC. A previously published outcome was used to determine if patients received time-sensitive interventions. Driving distance to the PTC was determined using Google Maps. Data were analyzed using descriptive statistics. RESULTS A total of 207 cases were identified (median age, 7 years; interquartile range, 2–12 years; 29% female; median Injury Severity Score [ISS], 11; median Revised Trauma Score [RTS], 8). Forty-three percent (90 patients; 95% confidence interval, 37–50%) of patients received a time-sensitive intervention; these cases had a median age of 6 years (interquartile range, 2–11 years; 32% female; median ISS, 13; median RTS, 8). Of the 117 patients who did not receive time-sensitive interventions, 81% were within 120 driving miles of the PTC and 49% were within 60 miles. CONCLUSION This study suggests an overuse of HEMS for interfacility transfer of injured pediatric patients to a PTC. Although these patients likely required the resources of a PTC, they could perhaps have been transported by ground ambulance without detriment. Further research is needed to investigate how interfacility transport modes are selected and if these decisions can be improved without increasing evaluation times at transferring facilities. LEVEL OF EVIDENCE Epidemiologic study, level V.

Consensus-Based Criterion Standard for the Identification of Pediatric Patients who Need EMS Transport to a Hospital with Higher-Level Pediatric Resources.

BACKGROUND Emergency medical services (EMS) providers must be able to identify the most appropriate destination facility when treating children with potentially severe medical illnesses. Currently, no validated tool exists to assist EMS providers in identifying children who need transport to a hospital with higher-level pediatric care. For such a tool to be developed, a criterion standard needs to be defined that identifies children who received higher-level pediatric medical care. OBJECTIVE The objective was to develop a consensus-based criterion standard for children with a medical complaint who need a hospital with higher-level pediatric resources. METHODS Eleven local and national experts in EMS, emergency medicine (EM), and pediatric EM were recruited. Initial discussions identified themes for potential criteria. These themes were used to develop specific criteria that were included in a modified Delphi survey, which was electronically delivered. The criteria were refined iteratively based on participant responses. To be included, a criterion required at least 80% agreement among participants. If an item had less than 50% agreement, it was removed. A criterion with 50% to 79% agreement was modified based on participant suggestions and included on the next survey, along with any new suggested criteria. Voting continued until no new criteria were suggested and all criteria received at least 80% agreement. RESULTS All 11 recruited experts participated in all seven voting rounds. After the seventh vote, there was agreement on each item and no new criteria were suggested. The recommended criterion standard included 13 items that apply to patients 14 years old or younger. They included IV antibiotics for suspicion of sepsis or a seizure treated with two different classes of anticonvulsive medications within 2 hours, airway management, blood product administration, cardiopulmonary resuscitation, electrical therapy, administration of specific IV/IO drugs or respiratory assistance within 4 hours, interventional radiology or surgery within 6 hours, intensive care unit admission, specific comorbid conditions with two or more abnormal vital signs, and technology-assisted children seen for device malfunction. CONCLUSION We developed a 13-item consensus-based criterion standard definition for identifying children with medical complaints who need the resources of a hospital equipped to provide higher-level pediatric services. This criterion standard will allow us to create a tool to improve pediatric patient care by assisting EMS providers in identifying the most appropriate destination facility for ill children.

Ketamine and intraocular pressure.

We commend Halstead and colleagues for their observational study of intraocular pressure (IOP) measurement during procedural sedation with ketamine. The simultaneous publication of their results and those of our recent report contribute important knowledge to emergency medicine practice and serve to dispel dogma whether ketamine use is associated with clinically meaningful changes of IOP. In part because each study approached this question using different analytic methods, the conclusion that there are no clinically meaningful associations is strengthened. Their comments regarding our study nonetheless deserve clarification. The authors noted that our study included only 25 participants and questioned whether this sample size, smaller than theirs, would detect statistically significant differences. To the contrary, we believe that we were able to answer the study question with a smaller sample size and that this is a study strength. The rationale for this follows. First, normal IOP changes minimally between early and late childhood (from approximately 10 to 15 mm Hg), and although there is notable diurnal variation in IOP for an individual, ocular hypertension is generally regarded as a sustained elevation above 22 mm Hg. That there are not clinically meaningful, age-related differences of IOP can be seen in Table 2 (with overlapping confidence intervals [CI]) and Figure 3 of the report by Halstead et al. Second, tonometry is not entirely benign and has potential to cause corneal abrasions. With these facts in mind, we considered that we could study participants ages 7 through 17 years as a single cohort to answer the study question and to do so with the smallest sample size possible. Indeed, we were able to answer the study question definitively with our sample of 25 participants, with the upper bounds of the 95% CIs for IOP measurements all less than 19 mm Hg at 1, 3, 5, 15, and 30 minutes after ketamine administration and the CIs for absolute change of IOP all less than 2.6 mm Hg at each of these times (Table 2 of our article). Thus, we demonstrated that clinically meaningful changes of IOP are unlikely to be associated with ketamine administration. We believe that this is the important and clinically relevant question at hand. We again applaud Halstead et al. for their work and for their contribution to emergency medicine practice, and believe that both studies are complementary in addressing prior concerns that ketamine use is associated with elevated IOP. doi: 10.1111/acem.12100