Seroprevalence of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) antibodies among healthcare workers with differing levels of coronavirus disease 2019 (COVID-19) patient exposure.

Healthcare employees were tested for antibodies against severe acute respiratory coronavirus virus 2 (SARS-CoV-2). Among 734 employees, the prevalence of SARS-CoV-2 antibodies was 1.6%. Employees with heavy coronavirus disease 2019 (COVID-19) exposure had similar antibody prevalence as those with limited or no exposure. Guidelines for PPE use seem effective for preventing COVID-19 infection in healthcare workers.

Healthcare outcomes in undocumented immigrants undergoing two emergency dialysis approaches
.

BACKGROUND: Current estimates suggest 6,500 undocumented end-stage renal disease (ESRD) patients in the United States are ineligible for scheduled hemodialysis and require emergent dialysis. In order to remain in compliance with Emergency Medicaid, an academic health center altered its emergency dialysis criteria from those emphasizing interdialytic interval to a set emphasizing numerical thresholds. We report the impact of this administrative change on the biochemical parameters, utilization, and adverse outcomes in an undocumented patient cohort. METHODS: This retrospective case series examines 19 undocumented ESRD patients during a 6-month transition divided into three 2-month periods (P1, P2, P3). In P1, patients received emergent dialysis based on interdialytic interval and clinical judgment. In P2 (early transition) and P3 (equilibrium), patients were dialyzed according to strict numerical criteria coupled with clinical judgment. RESULTS: Emergent criteria-based dialysis (P2 and P3) was associated with increased potassium, blood urea nitrogen (BUN), and acidosis as compared to P1 (p < 0.05). Overnight hospitalizations were more common in P2 and P3 (p < 0.05). More frequent adverse events were noted in P2 as compared to P1 and P3, with an odds ratio (OR) for the composite endpoint (intubation, bacteremia, myocardial infarction, intensive care unit admission) of 48 (5.9 - 391.2) and 16.5 (2.5 - 108.6), respectively. Per-patient reimbursement-to-cost ratios increased during criteria-based dialysis periods (P1: 1.49, P2: 2.3, P3: 2.49). DISCUSSION: Strict adherence to criteria-based dialysis models increases biochemical abnormalities while improving Medicaid reimbursement for undocumented immigrants. Alternatives to emergent dialysis are required which minimize cost, while maintaining dignity, safety, and quality of life.
.

Noninvasive sphenopalatine ganglion block for acute headache in the emergency department: a randomized placebo-controlled trial.

STUDY OBJECTIVE: We seek to test the efficacy of noninvasive sphenopalatine ganglion block for the treatment of acute anterior headache in the emergency department (ED) using a novel noninvasive delivery device. METHODS: We conducted a randomized, double-blind, placebo-controlled trial evaluating bupivacaine anesthesia of the sphenopalatine ganglion for acute anterior or global-based headache. This study was completed in 2 large academic EDs. Bupivacaine or normal saline solution was delivered intranasally (0.3 mL per side) with the Tx360 device. Pain and nausea were measured at 0, 5, and 15 minutes by a 100-mm visual analog scale. The primary endpoint was a 50% reduction in pain at 15 minutes. Telephone follow-up assessed 24-hour pain and nausea through a 0- to 10-point verbal scale and adverse effects. RESULTS: The median reported baseline pain in the bupivacaine group was 80 mm (IQR 66 mm - 93 mm) and 78.5 mm (IQR 64 mm to 91.75 mm) in the normal saline solution group. A 50% reduction in pain was achieved in 48.8% of the bupivacaine group (20/41 patients) versus 41.3% in the normal saline solution group (19/46 patients), for an absolute risk difference of 7.5% (95% confidence interval [CI] -13% to 27.1%). As a secondary outcome, at 24 hours, more patients in the bupivacaine group were headache free (24.7% difference; 95% CI 2.6% to 43.6%) and more were nausea free (16.9% difference; 95% CI 0.8% to 32.5%). CONCLUSION: For patients with acute anterior headache, sphenopalatine ganglion block with the Tx360 device with bupivacaine did not result in a significant increase in the proportion of patients achieving a greater than or equal to 50% reduction in headache severity at 15 minutes compared with saline solution applied in the same manner.

Improving specialty care follow-up after an ED visit using a unique referral system.

OBJECTIVE: Many patients discharged from the emergency department (ED) require urgent follow-up with specialty providers. We hypothesized that a unique specialty referral mechanism that minimized barriers would increase follow-up compliance over reported and historical benchmarks. METHODS: Retrospective review of all patients requiring urgent (within 1 month) specialty referrals in 2010 from a safety net hospital ED to dermatology, otolaryngology, neurology, neurosurgery, ophthalmology, urology, plastic surgery, general surgery, or vascular surgery clinics. After specialist input, all patients received a specific follow-up appointment before ED discharge via a specific scheduling service. Necessity for payment at the follow-up visit was waived. RESULTS: Of the 1174 receiving referrals, 85.6% of patients scheduled an appointment and 80.1% kept that appointment. After logistic regression analysis, the factors that remained significantly associated (P < .05) with appointment-keeping compliance were the specialty clinic type (dermatology, 61.5%, to ophthalmology, 98.0%), insurance status (other payer, 87.5%; commercial, 82.8%; Medicaid, 77.9%; Medicare, 85.7%; charity care program, 88.1%; self-pay, 73.0%), age (<18 years, 80.1%; 18-34 years, 75.0%; 35-49 years, 79.2%; 50-64 years, 85.9 %; >64 years, 93.9%), and mean length of time between ED visit and clinic appointment (kept, 10.5 days; not kept, 14.3 days). The specialty clinic (neurology, 72.8%, to vascular surgery, 100%; P < .001) was significantly associated with the likelihood of patients to complete the appointment-making process. Race/Ethnicity was not associated with either scheduling or keeping an appointment. CONCLUSION: A referral process that minimizes barriers can achieve an 80% follow-up compliance rate. Age, insurance, specialty type, and time to appointment are associated with noncompliance.

An analysis of a case manager-driven emergent dialysis program.

PURPOSE OF THE STUDY: With the undocumented immigrant population in the United States on the rise, an increase in the number of patients with end-stage renal disease without access to a regular dialysis chair continues. This leaves hospital systems with the difficult decision of how best to care for this population. We sought to evaluate the feasibility, effectiveness, and costs of a case manager-driven emergent dialysis program. We hypothesized that this program would be feasible and would result in similar costs as the previous regularly scheduled dialysis program in place at our institution. PRIMARY PRACTICE SETTING: The study was conducted at Wishard Memorial Hospital, which is an urban public hospital in Indianapolis, IN. METHODOLOGY AND SAMPLE: We performed a before (March 11, 2010, to June 11, 2010) and after (June 14, 2010, to September 14, 2010) study to compare the treatment of a 6-patient cohort of dialysis patients without a "dialysis home" before and after the case manager-driven emergent dialysis program, using secondary data. RESULTS: The case manager-driven emergent dialysis process was feasible and led to a total expense of $101,802 as compared with a total cost of $122,890 when providing regular dialysis to this subset of patients. There were no differences in intensive care unit days, length of stay, and complications between the 2 groups in the short study period. IMPLICATIONS FOR CASE MANAGEMENT PRACTICE: The dialysis population without a "dialysis home" is a high-risk population in need of intensive medical care but the approach to these patients continues to be debated. Although this study does not prove or necessarily support a dialysis on "emergent" basis approach over chronic, scheduled dialysis, the study does demonstrate that case management can play a significant role in the care of these patients. Case management oversight and management of our patient population resulted in costs equal to, or better than, those who received chronic dialysis care without a difference in complications over a 6-month study period.

Measuring in-cabin school bus tailpipe and crankcase PM2.5: a new dual tracer method.

Exposures of occupants in school buses to on-road vehicle emissions, including emissions from the bus itself, can be substantially greater than those in outdoor settings. A dual tracer method was developed and applied to two school buses in Seattle in 2005 to quantify in-cabin fine particulate matter (PM2.5) concentrations attributable to the buses' diesel engine tailpipe (DPMtp) and crankcase vent (PMck) emissions. The new method avoids the problem of differentiating bus emissions from chemically identical emissions of other vehicles by using a fuel-based organometallic iridium tracer for engine exhaust and by adding deuterated hexatriacontane to engine oil. Source testing results showed consistent PM:tracer ratios for the primary tracer for each type of emissions. Comparisons of the PM:tracer ratios indicated that there was a small amount of unburned lubricating oil emitted from the tailpipe; however, virtually no diesel fuel combustion products were found in the crankcase emissions. For the limited testing conducted here, although PMck emission rates (averages of 0.028 and 0.099 g/km for the two buses) were lower than those from the tailpipe (0.18 and 0.14 g/km), in-cabin PMck concentrations averaging 6.8 microg/m3 were higher than DPMtp (0.91 microg/m3 average). In-cabin DPMtp and PMck concentrations were significantly higher with bus windows closed (1.4 and 12 microg/m3, respectively) as compared with open (0.44 and 1.3 microg/m3, respectively). For comparison, average closed- and open-window in-cabin total PM2.5 concentrations were 26 and 12 microg/m3, respectively. Despite the relatively short in-cabin sampling times, very high sensitivities were achieved, with detection limits of 0.002 microg/m3 for DPMtp and 0.05 microg/m3 for PMck.

A task analysis of emergency physician activities in academic and community settings.

STUDY OBJECTIVE: We characterize and compare the work activities, including peak patient loads, associated with the workplace in the academic and community emergency department (ED) settings. This allows assessment of the effect of future ED system operational changes and identifies potential sources contributing to medical error. METHODS: This was an observational, time-motion study. Trained observers shadowed physicians, recording activities. Data included total interactions, distances walked, time sitting, patients concurrently treated, interruptions, break in tasks, physical contact with patients, hand washing, diagnostic tests ordered, and therapies rendered. Activities were classified as direct patient care, indirect patient care, or personal time with a priori definitions. RESULTS: There were 203 2-hour observation periods of 85 physicians at 2 academic EDs with 100,000 visits per year at each (N=160) and 2 community EDs with annual visits of 19,000 and 21,000 (N=43). Reported data present the median and minimum-maximum values per 2-hour period. Emergency physicians spent the majority of time on indirect care activities (academic 64 minutes, 29 to 91 minutes; community 55 min, 25 to 95 minutes), followed by direct care activities (academic 36 minutes, 6 to 79 minutes; community 41 minutes, 5 to 60 minutes). Personal time differed by location type (academic 6 minutes, 0 to 66 minutes; community 13 minutes, 0 to 69 minutes). All physicians simultaneously cared for multiple patients, with a median number of patients greater than 5 (academic 7 patients, 2 to 16 patients; community 6 patients, 2 to 12 patients). CONCLUSION: Emergency physicians spend the majority of their time involved in indirect patient care activities. They are frequently interrupted and interact with a large number of individuals. They care for a wide range of patients simultaneously, with surges in multiple patient care responsibilities. Physicians working in academic settings are interrupted at twice the rate of their community counterparts.

ED procedural sedation of elderly patients: is it safe?

OBJECTIVE: Emergency physicians routinely perform emergency department procedural sedation (EDPS), and its safety is well established. We are unaware of any published reports directly evaluating the safety of EDPS in older patients (≥65 years old). Many EDPS experts consider seniors to be at higher risk. The objective was to evaluate the complication rate of EDPS in elderly adults. METHODS: This was a prospective, observational study of EDPS patients at least 65 years old, as compared with patients aged 18 to 49 and 50 to 64 years. Physicians were blind to the objectives of this research. The study protocol required an ED nurse trained in data collection to be present to record vital signs and assess for any prospectively defined complications. We used American Society of Anesthesiologists (ASA) physical status classification for systemic disease to evaluate and account for the comorbidities of patients. We used the Fisher exact test for the difference in proportions across age groups and analysis of variance for the differences in dosing across age and ASA categories. RESULTS: During the 4-year study, we enrolled 50 patients at least 65 years old, 149 patients aged 50 to 64 years, and 665 patients aged 18 to 49 years. Adverse event rates were 8%, 5.4%, and 5.2%, respectively (P = .563). The at least 65 years age group represented a greater percentage of those with higher ASA scores (P < .001). The average total sedative dose in the at least 65 years group was significantly lower than the comparisons (P < .001). CONCLUSIONS: This study demonstrated no statistically significant difference in complication rate for patients 65 years or older. There was a significant decrease in mean sedation dosing with increased age and ASA score.

Quantification of Self Pollution from Two Diesel School Buses using Three Independent Methods.

We monitored two Seattle school buses to quantify the buses' self pollution using the dual tracers (DT), lead vehicle (LV), and chemical mass balance (CMB) methods. Each bus drove along a residential route simulating stops, with windows closed or open. Particulate matter (PM) and its constituents were monitored in the bus and from a LV. We collected source samples from the tailpipe and crankcase emissions using an on-board dilution tunnel. Concentrations of PM(1), ultrafine particle counts, elemental and organic carbon (EC/OC) were higher on the bus than the LV. The DT method estimated that the tailpipe and the crankcase emissions contributed 1.1 and 6.8 mug/m(3) of PM(2.5) inside the bus, respectively, with significantly higher crankcase self pollution (SP) when windows were closed. Approximately two-thirds of in-cabin PM(2.5) originated from background sources. Using the LV approach, SP estimates from the EC and the active personal DataRAM (pDR) measurements correlated well with the DT estimates for tailpipe and crankcase emissions, respectively, although both measurements need further calibration for accurate quantification. CMB results overestimated SP from the DT method but confirmed crankcase emissions as the major SP source. We confirmed buses' SP using three independent methods and quantified crankcase emissions as the dominant contributor.

ED patient falls and resulting injuries.

INTRODUCTION: Patient falls are the most common adverse events reported in hospitals. There is a growing body of literature on inpatient falls but a lack of data on ED falls. We applied the Hendrich II Fall Risk Model to patients who fell during their ED stays and provided a description of the patients and their injuries. METHODS: We retrospectively reviewed the medical records of all patients who fell in the emergency department during a 2-year period. We collected the 8 assessment parameters for high-risk fall identification in the Hendrich II Fall Risk Model. We also collected subject characteristics, circumstances surrounding the falls, fall-related injuries, and ED disposition. RESULTS: Fifty-seven falls were recorded, representing a rate of 0.288 falls per 1000 patient visits. The average age was 50 years, and a median of 48. 67% were men. Twenty-one subjects had a Hendrich II Model score of 5 of greater, which represents a sensitivity of 37.5%. Eleven subjects (19.6%) were intoxicated with alcohol. Eleven subjects (19.6%) received a potentially sedating medication prior to the fall. Thirty-six subjects (64.3%) fell in their ED rooms. Six subjects (10.7%) fell in the restroom. Three falls (5.4%) resulted in lacerations and 2 falls (3.6%) resulted in hematomas. DISCUSSION: The Hendrich II Fall Risk Model may not reliably identify patients at high risk of falling in the ED setting. It may be necessary to develop an emergency department-specific fall model considering additional factors, such as intoxication and receipt of potentially sedating medications.

Detailed characterization and profiles of crankcase and diesel particulate matter exhaust emissions using speciated organics.

A monitoring campaign was conducted in August-September 2005 to compare different experimental approaches quantifying school bus self-pollution. As part of this monitoring campaign, a detailed characterization of PM2.5 diesel engine emissions from the tailpipe and crankcase emissions from the road draft tubes was performed. To distinguish between tailpipe and crankcase vent emissions, a deuterated alkane, n-hexatriacontane-d74 (n-C36D74) was added to the engine oil to serve as an intentional quantitative tracer for lubricating oil PM emissions. This paper focuses on the detailed chemical speciation of crankcase and tailpipe PM emissions from two school buses used in this study. We found that organic carbon emission rates were generally higher from the crankcase than from the tailpipe for these two school buses, while elemental carbon contributed significantly only in the tailpipe emissions. The n-C36D74 that was added to the engine oil was emitted at higher rates from the crankcase than the tailpipe. Tracers of engine oil (hopanes and steranes) were present in much higher proportion in crankcase emissions. Particle-associated PAH emission rates were generally very low (< 1 microg/km), but more PAH species were present in crankcase than in tailpipe emissions. The speciation of samples collected in the bus cabins was consistent with most of the bus self-pollution originating from crankcase emissions.

A comparison of observed versus documented physician assessment and treatment of pain: the physician record does not reflect the reality.

STUDY OBJECTIVE: The Joint Commission requires "appropriate assessment" of patients presenting with painful conditions. Compliance is usually assessed through retrospective chart analysis. We investigate the discrepancy between observed physician pain assessment and that subsequently documented in the medical record. METHODS: This was an observational study using a trained investigator watching bedside interactions of emergency physicians. Using a priori definitions, the investigator recorded whether the patient volunteered the presence of pain, physician inquiry about pain, attempts to quantify the pain, treatment offered/rendered, and any assessment of the response to therapy. An independent investigator subsequently assessed the patient's chart for documentation of pain assessment, therapy rendered, and response to treatment. Children younger than 5 years and patients with major trauma, altered mental status, or nontraumatic chest pain were excluded. The institutional review board approved the protocol, the physicians agreed to participate in an "ergonomic study" without knowing the exact nature of data collection, and patients released their records. RESULTS: The investigator observed 209 patient encounters. Physicians acknowledged the patients' pain 98.1% of the time but documented its presence in 91.7%. Physicians attempted to quantify the patient's pain in 61.5% of encounters but documented that attempt in only 38.9%. Treatment was offered in 79.9% and recorded in 31.7% of charts. When treatment was offered, the patient's response to the therapy was recorded only 28% of the time. CONCLUSION: Physicians almost always assess and treat patient pain but infrequently record those efforts. The patient's chart is a poor surrogate marker for pain assessment and care by emergency physicians and may not be suitable for use as a compliance assessment tool. Research methodology using retrospective chart analysis may be affected by this phenomenon, suggesting the potential for underestimation of patient pain assessment and treatment by emergency physicians.

Emergency department procedural sedation with propofol: is it safe?

Propofol is a sedative agent gaining popularity for Emergency Department Procedural Sedation (EDPS). However, some institutions across the country continue to restrict the use of propofol secondary to safety concerns. The purpose of our study was to evaluate the complication rate of EDPS with propofol. We conducted a prospective, observational, multi-center study of EDPS patients aged > or = 18 years, consenting to procedural sedation with propofol. Eighty-two patients from two Level I trauma centers were enrolled between August 1, 2002 and January 31, 2003. Transient hypoxemia was the only noted sedation complication. Nine patients (11%) had brief hypoxemia. The combined average hypoxemia time was 1.2 min (SD 0.4), and in all instances responded to simple airway maneuvers or increased oxygen concentration. No patient required advanced airway maneuvers such as intubation or even positive pressure ventilation. EDPS with propofol seems to be safe in our population.

An assessment of the association of bispectral index with 2 clinical sedation scales for monitoring depth of procedural sedation.

OBJECTIVE: We conducted a study to assess the correlation of bispectral index (BIS) to 2 clinical sedation scales. METHODS: This was a prospective, observational study. The BIS number was recorded at baseline and every 30 seconds. One investigator separately monitored the patients for depth of sedation using the Observer's Assessment of Alertness/Sedation and the Continuum of Depth of Sedation scales. RESULTS: During the 6-month period, 75 patients were enrolled. The Spearman correlation between the BIS and the Observer's Assessment of Alertness/Sedation was 0.59 (95% confidence interval [CI], 0.44-0.74). The Spearman correlation between the BIS and the Continuum of Depth of Sedation was 0.53 (95% CI, 0.36-0.70). The mean minimum BIS for patients without a complication was 70 (SD, 15.9) compared with 68 (SD, 12.9) for patients with a complication (difference = 2; 95% CI, -7-11). CONCLUSIONS: Our study demonstrated moderate correlation between BIS and the 2 clinical sedation scales. The correlation is not strong enough to be used reliably in a clinical setting. The mean minimum BIS scores were not significantly different for those with sedation complications vs those without complications.

A more explicit grading scale decreases grade inflation in a clinical clerkship.

OBJECTIVES: The medical education literature contains few publications about the phenomenon of grade inflation. The authors' clinical clerkship grading scale suffered from apparent inflation relative to the recommended university distribution. The investigators hypothesized that a simple change of the shift grading cards, using explicit criteria, would decrease this grade inflation and aid to redistribute the shift evaluations. METHODS: This was a before-and-after study examining medical student shift evaluation grades. Evaluators and students were blinded to the purpose of the card change and were unaware that a study was being conducted. Beginning June 1, 2005, the authors altered the shift evaluation cards from the previous four choices of honors, high pass, pass, or fail to five choices of upper 5%, upper 25%, expected, below expected, or far below expected, and explicit grading criteria were provided. No other interventions to alter the grade distribution occurred. Data were collected on all evaluations from June 1, 2004, to March 31, 2005 (before change), and compared with data on all evaluations from June 1, 2005, to March 31, 2006 (after change). RESULTS: A total of 3,349 evaluations were analyzed: 1,612 before the card change and 1,737 after the change. The grade distribution before the card change was as follows: honors, 22.6%; high pass, 49.0%; pass, 28.4%; and fail, 0%. This compared with the following ratings after the card change: upper 5%, 9.8%; upper 25%, 41.2%; expected, 46.2%; below expected, 2.8%; and far below expected, 0% (p < 0.001). CONCLUSIONS: A simple change in shift evaluation cards to include more explicit grading criteria resulted in a significant change in grade distribution and greatly decreased grade inflation.

An analysis of maximum vehicle G forces and brain injury in motorsports crashes.

PURPOSE: Traumatic brain injury from automobile crashes is a major source of trauma deaths. The investigation of crashes to understand factors of occupant injuries is an established practice. Our objective was to evaluate the association between vehicle G forces (G) sustained on impact and brain injury in motor sports crashes. METHODS: We analyzed data regarding Indy Racing League (IRL) car crashes from 1996 to 2003 and compared the likelihood of head injury in those drivers who were in a vehicle that sustained an impact of > or =50 G versus those with a lesser impact. The mean maximal G for those with head injury was compared with those without head injury. RESULTS: We analyzed 374 crashes. A driver in a crash with an impact of > or =50 G developed a head injury 16.0% (30/188) versus 1.6% (3/186) in those of <50 G (P < 0.001). The mean peak G for those with head injury was 79.6 (SD 28.5) versus 50.6 (SD 28.0) in those with no head injury (P < 0.001). CONCLUSION: Findings were that IRL car crashes with peak vehicle G > or = 50 were associated with the development of traumatic brain injuries.

Impact of emergency medicine faculty on door to thrombolytic time.

The objective of this study was to determine the impact of Emergency Medicine (EM) faculty presence on timely thrombolytic therapy for acute myocardial infarction in the Emergency Department (ED). We performed a retrospective study of data regarding acute myocardial infarction patients in the ED of a large urban teaching hospital. Data were collected from January 1, 1998 to December 31, 1999 when EM faculty were not present in the ED and from January 1, 2001 to December 31, 2002 when they were. We compared median time from patient arrival to thrombolytics, percent of patients receiving thrombolytics within 30 min of arrival, and percent of patients with indications for primary revascularization who received it before and after EM faculty presence. The results indicate that EM faculty presence resulted in a decrease in median time from arrival to thrombolytic administration of 17 min (95% CI: 9, 28). Before EM faculty presence, the median time was 44 min as compared to 24 min post-EM faculty presence. Patients received thrombolytic therapy within 30 min 25.8% of the time before EM faculty presence as compared to 65.4% with EM faculty presence; an absolute increase of 39.6% (95% CI: 23.0%, 56.3%). Primary revascularization occurred in 56.9% of eligible patients pre-EM faculty presence and 81.4% post-EM faculty presence; an increase of 24.5% (95% CI: 13.6%, 35.4%). We conclude that the introduction of Emergency Medicine faculty significantly improved the quality of care for acute myocardial infarction patients in a large urban Emergency Department.

Droperidol vs prochlorperazine for the treatment of acute headache.

To determine if droperidol i.v. is as effective as prochlorperazine i.v. in the emergency department (ED) treatment of uncomplicated headache, a randomized, controlled, blinded study was conducted in the Emergency Departments of two urban teaching hospitals. Patients >or= 18 years old with crescendo-onset headache were eligible for inclusion. Ninety-six patients (48 in each group) were randomized to receive droperidol 2.5 mg i.v. or prochlorperazine 10 mg i.v. Baseline characteristics were similar between the two study groups. For the main study outcome, 83.3% in the droperidol group and 72.3% in the prochlorperazine group reported 50% pain reduction at 30 min (p <.01; one-sided test of equivalence). The mean decrease in headache intensity was 79.1% (SD 28.5%) in the droperidol group and 72.1% (SD 28.0%) in the prochlorperazine group (p =.23). It is concluded that droperidol i.v. provided a similar reduction of headache as achieved with prochlorperazine i.v. with a similar incidence of akathisia.

A prospective, randomized, double-blind comparison of buffered versus plain tetracaine in reducing the pain of topical ophthalmic anesthesia.

STUDY OBJECTIVE: We determine whether buffering ocular tetracaine hydrochloride reduces the pain of instillation. METHODS: We conducted a prospective, randomized, double-blind, 2-treatment, 2-period crossover, single center study of healthy volunteers 18 years of age or older. Participants were randomized to receive either 2 drops of buffered or plain tetracaine in a randomly assigned eye. After a mean wash out period of 24 days (range 7 to 54 days), participants returned to have 2 drops of the other medication instilled in the same eye. The participants recorded the pain of instillation on a 100-mm visual analog scale (VAS) immediately and 5 minutes after instillation. Adverse events were also recorded at these intervals. The primary outcome measure was the intensity of pain as measured on a VAS immediately after instillation. RESULTS: Sixty persons were enrolled in the study, with 100% follow up. Immediately after instillation, the adjusted mean VAS score for buffered tetracaine was 29.1 mm, and the adjusted mean VAS score for plain tetracaine was 16.0 mm. The estimated difference was 13.1 mm (95% confidence interval 6.9 to 19.3 mm). CONCLUSION: Buffering of tetracaine hydrochloride significantly increases the pain of its instillation in healthy volunteers, suggesting that pain with instillation of ocular anesthetics is not dependent on low pH.