Medical documentation of burn injuries

Apart from methylene blue, other substances as for example tetracycline and disulphine blue were examined.

Fluorescence-fluorometry

This method is based on the activation of fluorescence phenomena after an intravenous application of fluorescent substances. In partial deep burn areas, fluorescence occurs within 10 minutes; in deep burn areas fluorescence does not occur [18]. Thus the measures need to be carried out regularly to determine burn depth. The advantage of this method is its possibility of differentiation between partial and full thickness burns [26].

Indocyanine-videoangiography

This is a special kind of fluorescence-fluorometry. After applying indocyanine green, the dynamic alteration of the perfusion in the tissue can be recorded by videoangiography. The recording of indocyanine green in the tissue as well as the degradation of the substance provide information about the disturbed microcirculation. This method is highly sensitive and suitable for clinical application [33]. However, ointments and creams can distort the results [24]. The indocyanine clearance can also serve as an indicator for liver function based on perfusion [67].

Laser-Doppler flowmetry

Laser-Doppler flowmetry (LDF) and Laser-Doppler perfusion monitoring (LDPM) are proceedings which are based on the alteration of wavelength of laser light upon contact with moving erythrocytes. When a tube is applied directly onto the skin, measuring is carried out in 1 mm depth. Exactness is 90%–97%.

Laser Doppler Imaging (LDI) and Laser Doppler Perfusion Imaging (LDPI) are non-contact procedures. After scanning, a photocurrent is produced which shows tissue perfusion. According to the relevant literature the exactness to differentiate between wounds that heal within three weeks and wounds that require more time to heal is 99% [31]. The validity of this method can be improved by repeated scans, heat provocation or the combination with

other methods. Shortcomings may arise due to the curved surface, the limited scan area and the time that is required for the scan. Light, surface treatment and infection might distort the results [3].

Polarization dependent optical coherence tomography

This non-invasive method is based on the fact that burn depth correlates with alterations of the skin’s double refraction [13]. Animal experiments have shown promising results and clinical application is expected soon [13, 32, 54].

Reflexion-optical multispectralanalytic imaging method

It is based on the relative patency of the skin for infrared rays. Oxygen reduced hemoglobin reflects less light than tissue that is rich in oxygen. This method was introduced in 1973 [3]. In clinical examinations, the burn depth indicator, which was developed afterwards, showed an exactness of 79 % in wounds for which surgeons were not able to determine their wound characteristics. The highest exactness could be achieved on day 3 after burn trauma. Further developments of the method are based on spectral analysis of four characteristic wavelengths to differentiate burn depth. From the data, false-color photography is produced, which shows the burn depth. The combination of a normal image with the false-color image as well as the simple and fast handling of the system contribute to a high practicability of the method [17]. By combining with the software BurnCase 3D an objective general interpretation of a burn injury was possible for the first time due to a direct transmission of the false-color images to a model that is adjusted to height, weight, sex and type [16].

Burn extent

Basic principles of determining the burn extent

The extent of a burn injury is indicated by the proportion of burned body surface in % of the total body surface. First degree burns are not considered. The

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accurate estimation of patient’s burned body surface area as percentage of the total body surface area (TBSA) is crucial for an adequate primary treatment (ventilation, fluid resuscitation, drug dosages, etc.) and for the decision of transferring to specialized burn units [44].

Variance of evaluation

Evaluating the extent of a burn injury seems to be easy, but is difficult. A study comparing the initial evaluation in the emergency unit with the definite evaluation showed that the extent of the burn injury was overestimated by more than 100% in 24 out of 134 patients [23].

In addition to this, the problem of incorrect representation of the real patient by charts, the complexity of projection from 3D to 2D resides as source of error. Nichter et al. describes an error rate of 29% due to this systemic error, using Rule of Nines and Lund Browder Chart [51].

Another system immanent error is based on the Body Mass Index (BMI). Especially in underweight and obese patients as well as in infants the estimation errors of standard methods are significantly increased [20, 40, 70].

Influence of the professional background

There was no significant difference between physicians and nursing staff when evaluating the extent of a burn injury [23].

Methods to determine burn extent

Rule of palm

Rule: The surface of the patient’s palm is about 1% of the total body surface.

Discussion: The rule of palm leads to an overestimation of the real extent of the burn injury by 10%–20%. In adults, the extent of a palm is 0.78% +/− 0.08% of the total body surface [2]. There are also gen- der-related differences as the palm of a man is 0.8% and the palm of a woman is 0.7% of the total body surface. The isolated palm without fingers is 0.5% in men and 0.4% in women. In children, the palm is 0.92% and the palm without fingers 0.52% [48].

“Rule of Nines” according to Wallace

Rule: Cited in Knaysi et al.: arms 9% of total body surface each, legs 18% each, chest and back 18% each, head 7% neck 2%, hands and feet, genitals 1% each [36].

Discussion: The “Rule of Nines” has shown good results in patients weighing 10 kg–80 kg. The application of the “Rule of Nines” often leads to an overestimation of the real extent of the burn injury [71], especially in patients with an increased body mass index [6]. In patients weighing more than 80 kg it is more promising to apply a “Rule of Fives”, under 10 kg a “Rule of Eights” [40]. “Rule of Nines” is inaccurate and should not be applied in infants and children due to the strong change of proportions during growth.

Lund Browder Chart

The Lund Browder Chart assigns various age groups to various body proportions and is thus more exact than the “Rule of Nines” [42].

Discussion: Several authors have shown an overestimation of the extent of the burn injury when applying the Lund Browder Chart [51]. Alm showed in 90% of the cases, an overestimation of the burn extent by 17.8% on average [1]. Nichter et al. showed an overestimation by 12.4% on average [51]. This form of evaluation has system immanent errors because it is based on only one type of physique. Various forms of corpulence and different weight categories cannot be considered. The standardization to different age groups in children (Years: 1, 5, 10, 15) is a rather approximate one, as the biggest changes in proportions of children happen during the first years.

Additional information sheets for reporting burn injuries

Insurance companies often ask for an additional information sheet as report of severe burn injuries. It mostly is a more or less modified Lund Browder Chart.

Discussion: If the burn extent primarily is determined according to this information sheet, it later serves as a basis for determining the surface of body

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