Harborview burns--1974 to 2009

Abstract

Background: Burn demographics, prevention and care have changed considerably since the 1970s. The objectives were to 1) identify new and confirm previously described changes, 2) make comparisons to the American Burn Association National Burn Repository, 3) determine when the administration of fluids in excess of the Baxter formula began and to identify potential causes, and 4) model mortality over time, during a 36-year period (1974-2009) at the Harborview Burn Center in Seattle, WA, USA.

Methods and findings: 14,266 consecutive admissions were analyzed in five-year periods and many parameters compared to the National Burn Repository. Fluid resuscitation was compared in five-year periods from 1974 to 2009. Mortality was modeled with the rBaux model. Many changes are highlighted at the end of the manuscript including 1) the large increase in numbers of total and short-stay admissions, 2) the decline in numbers of large burn injuries, 3) that unadjusted case fatality declined to the mid-1980s but has changed little during the past two decades, 4) that race/ethnicity and payer status disparity exists, and 5) that the trajectory to death changed with fewer deaths occurring after seven days post-injury. Administration of fluids in excess of the Baxter formula during resuscitation of uncomplicated injuries was evident at least by the early 1990s and has continued to the present; the cause is likely multifactorial but pre-hospital fluids, prophylactic tracheal intubation and opioids may be involved.

Conclusions: 1) The dramatic changes include the rise in short-stay admissions; as a result, the model of burn care practiced since the 1970s is still required but is no longer sufficient. 2) Fluid administration in excess of the Baxter formula with uncomplicated injuries began at least two decades ago. 3) Unadjusted case fatality declined to ∼6% in the mid-1980s and changed little since then. The rBaux mortality model is quite accurate.

Figure 1. Catchment Area 2005–2009.

The majority of referrals come from Alaska, WA, the panhandle of Idaho and western Montana.

Figure 2. Admissions Over Time.

Panel A – The number of standard (Type 1) admissions was stable over the several decades. (1974 was a partial year) Panel B – The incidence rate of standard admissions declined from the mid-1980s to the mid-1990s and has been stable since then. (1974 was a partial year) Panel C – The majority (72–98%) of the short-stay admissions originated in the eight WA State counties surrounding Seattle with a slight decline over time. Panel D – There was a decline in short-stay admissions (Type 2) to other WA State hospitals and an increase to Harborview.

Figure 3. TBSA% Over Time for Standard Admissions.

The median TBSA% declined to the mid-1980s and subsequently varied from 7% to 10%. The 75^th percentile TBSA% also declined to the mid-1980s and then varied from 12% to 20%. The 25^th percentile was stable between 3% and 5%.

Figure 4. Admissions with TBSA% >20%.

Panel A – There was no trend over time to the number of admissions per year with TBSA% >20%. Panel B – The incidence rate of admissions with TBSA >20% declined from approximately 1.5 in the late 1970s to approximately 0.5 in 2009. Panel C – The 75^th percentile and median TBSA% declined modestly over time: 75^th percentile: ∼60 to 50% and median: ∼40 to 35%.

Figure 5. Incidence Rate of Medicaid Coverage.

Panel A – The incidence rate of standard (Type 1) admissions of children covered by Medicaid was similar to those covered by other payers. Panel B – The incidence rate of short-stay (Type 2) admissions of children covered by Medicaid was lower than for other payers but rose to similar levels. Panel C – The incidence rate of standard (Type 1) admissions of adults covered by Medicaid was higher than for those covered by other payers. Panel D – The incidence rate of short-stay (Type 2) admissions of adults covered by Medicaid was similar to those covered by other payers. (WA State data of Medicaid eligibility was not available prior to 2000. Incidence rates are small so are expressed in scientific notation. WA State segregates children into ≤18 so the age breakdown is slightly different from the remainder of the manuscript.).

Figure 6. Incidence Rate by Etiology for Standard (Type 1) Admissions.

Panel A – The incidence rates for children generally rose until ∼1990, declined until ∼2000 and may have stabilized. The increase and decrease was most profound for scald burns. Panel B – The incidence rates for adults of flame, contact, flash, grease, and electrical burns were largely stable over the years. The incidence rate of scald burns declined in the 1990s and has stabilized since then.

Figure 7. Burn Surgery.

Panel A – The percent of standard (Type 1) admissions treated surgically was ∼50% over the entire time period. Panel B – If treated surgically, the mean number of procedures was approximately two for all years, except for the partial year 1974. Panel C – The total number of burn procedures rose when excision became standard procedure and then varied between 200 and 300 until 2009 when it surged to 400. Panel D – Twenty-one persons underwent more than 5 procedures in 2009, which explains the increase to 400 burn procedures. Panel E – The maximum number of procedures for any one person was twenty-one in 1988.

Figure 8. Mortality Standardized to the rBaux Predicted.

Observed mortality was about 1.5 times higher than rBaux predicted mortality prior to 1980, and was about 1.25 times rBaux predicted mortality from ∼1980 to ∼2000. Since ∼2005 observed mortality has been less than rBaux predicted mortality. The adjusted odds of death from the regression (shown in red) was higher for all half-decades compared to 1975–1979 except for the most recent half decade.

Figure 9. Days to Death by Groups.

There was no trend over time to the number of persons placed on Comfort Care or to the number of persons who were not placed on comfort care but who died within eight days. However the number of persons who died after seven days decreased to the mid-1980s and again in 2005–2009.

Figure 10. Frequency and rBaux Scores of Comfort Care.

Panel A – There was no trend over time to the number of persons placed on comfort care. Panel B – There was no trend over time to the rBaux scores of persons placed on comfort care.