Near-drowning and drowning classification: a proposal to stratify mortality based on the analysis of 1,831 cases

To establish an updated classification for near-drowning and drowning (ND/D) according to severity, based on mortality rate of the subgroups.

We reviewed 41,279 cases of predominantly sea water rescues from the coastal area of Rio de Janeiro City, Brazil, from 1972 to 1991. Of this total, 2,304 cases (5.5%) were referred to the Near-Drowning Recuperation Center, and this group was used as the study database. At the accident site, the following clinical parameters were recorded: presence of breathing, arterial pulse, pulmonary auscultation, and arterial BP. Cases lacking records of clinical parameters were not studied. The ND/D were classified in six subgroups: grade 1--normal pulmonary auscultation with coughing; grade 2--abnormal pulmonary auscultation with rales in some pulmonary fields; grade 3--pulmonary auscultation of acute pulmonary edema without arterial hypotension; grade 4--pulmonary auscultation of acute pulmonary edema with arterial hypotension; grade 5--isolated respiratory arrest; and grade 6--cardiopulmonary arrest.

From 2,304 cases in the database, 1,831 cases presented all clinical parameters recorded and were selected for classification. From these 1,831 cases, 1,189 (65%) were classified as grade 1 (mortality=0%); 338 (18.4%) as grade 2 (mortality=0.6%); 58 (3.2%) as grade 3 (mortality=5.2%); 36 (2%) as grade 4 (mortality=19.4%); 25 (1.4%) as grade 5 (mortality=44%); and 185 (10%) as grade 6 (mortality=93%) (p<0.000001).

The study revealed that it is possible to establish six subgroups based on mortality rate by applying clinical criteria obtained from first-aid observations. These subgroups constitute the basis of a new classification.