The Francis Smith Classification

To solve the inherent problems of the Golding Classification, Francis and Smith proposed a new descriptive classification system that focused on

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clinical presentation rather than etiology of DI ^ . It contained descriptive categories that served a dual purpose of capturing actual clinical manifestations (e.g., the dynamic evolution and organ systems involved) as well as detailing factors relevant to etiological considerations (e.g., latency, inert gas burden and evidence of pulmonary barotrauma). This system offered flexibility, provided more relevant information and had a much higher degree of concordance between clinicians (see Table 2.2.1-2.).

The greatest utility of this classification system is its ability to describe and adapt to the evolving signs and symptoms of presumed DI in a diver. However, it does not establish a diagnosis, only factors relevant to the probability thereof within a descriptive matrix of an evolving clinical presentation 34. However, a collection of these descriptions can be used for clinical comparison and to examine trends. The latter can then be analyzed in the pursuit of underlying pathophysiological mechanisms and - based on they probability of diagnosis generated by the various determinants - a specific diagnosis may be assigned with appropriate nomenclature or descriptions of symptom-clusters. Kelleher has shown that useful predictions regarding outcome can be made using such data 35.

Table 2.2.1-2. The Francis & Smith Classification for Dysbaric Illness_

• Evolution o Spontaneously Recovery (Clinical improvement is evident) o Static (No change in clinical condition) o Relapsing (Relapsing symptoms after initial recovery)

• Progressive (Increasing number or severity of signs)

o Neurological o Cardiopulmonary o Limb pain exclusively o Skin o Lymphatic o Vestibular

o Time before surfacing o Time after surfacing (or estimate)

• Gas Burden o Low (e.g., within NDL) o Medium (e.g., Decompression Dive) o High (e.g., Violation of Dive Table)

• Evidence of Barotrauma o Pulmonary (Yes / No) o Ears o Sinuses

• Other Comments

Unfortunately, although the Francis / Smith system has received increasing acceptance, its strength has also remained its fundamental deficiency - the inability to assign a specific diagnosis. Clinicians and statisticians ultimately need to work with diagnoses or case definitions. These have remained elusive. Nevertheless, the current recommendation of the European Committee for Hyperbaric Medicine (Type 1 recommendation) is to provisionally accept the Francis and Smith classification until a superior

system emerges .

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