Type:
Educational Exhibit
Keywords:
Foreign bodies, CT, Conventional radiography, Thorax
Authors:
R. Scandiffio1, C. Giaconi1, M. Barattini2, P. Vagli1, P. Bemi1, A. Mantarro1, C. Bartolozzi1; 1Pisa/IT, 2Carrara (MS)/IT
DOI:
10.1594/ecr2011/C-1566
Background
Drowning is a suffocation by summersion [1],
especially in water; it is an important cause of death and morbidity,
especially in young age and is usual much higher in males than in females.
In Italy,
from 1969 to 1997 the mortality dropped from 1200 to 500 cases/year,
and mortality rates decreased in all the age subgroups,
but particularly in that of young people; this analysis indicates that some general factors have played an important role,
like a better education and information,
a greater surveillance by adults and a better organisation of summer resorts [2].
Near drowning is defined as survival,
at last for 24 hours,
after water inhalation; in Italy there are not statistical data about near drowning. Unconsciousness can be absent,
and pulmonary involvement can be present also without cessation of breathing.
There are some physiological considerations to do.
Immersion in thermoneutral water hardly causes cardiorespiratory distress in a healthy person.
Immersion in cold water causes reflexes called cold shock response,
that includes peripheral vasoconstriction,
42- 49% increase in heart rate and 59- 100% increase in cardiac output,
with a resulting increase in arterial and venous pressures.
These responses increase cardiac workload and,
coupled with catecolamine release,
can lead to cardiac arrhytmias.
In elderly people with cardiac and vascular disease,
immersion in cold water can cause cardiovascular accident,
than resulting in drowning.
Hypothermia play an important role in successful outcome in near drowning,
maybe related to brain protection from hypoxia; also diving response ( peripheral vasoconstriction,
apnoea,
bradycardia) is an important mechanism in oxygen saving.
After submersion,
conscious victim try to breath- hold until PaCO2 values are intolerable and respiratory muscle and cutaneous afferences force to take a breath (1).
Three stages of near drowning are usually recognize.
Stage 1.
Inhalation of a small amount of water leads to laryngospasm,
that is usually temporary and prevent further water aspiration.
Sometimes,
laryngospasm persists, negative pressure arises and can cause pulmonary lesions; this entity is called dry drowning.
Stage 2.
Patients present with laryngospasm and early water swallowing in the stomach.
Stage 3.
In 85- 90% of victims,
laryngospasm relaxes because of hypoxia and large amounts of water are inhalated.
In 10- 15% of patients,
laryngospasm persists and they present dry drowning.
Hypoxia is the first cause of damage in stage 2 and 3: lack of oxygen leads to cytokine release and permeability edema.
Aspirated water damages endothelium and pneumocytes,
and leads to surfactant production,
causing DAD (diffuse alveolar damage).
Aspiration of sand and debris can worsen the state.
If situation persists,
state can evolve into ARDS (adult respiratory distress syndrome) [3].
In these victims,
near- drowning associated pneumonia would be expected; the case fatality rate associated with near-drowning-associated pneumonia is 60% (30 deaths in 50 cases); several factors associated with the pathophysiology of near-drowning likely determine the probability that pneumonia will develop.
10% of victims don’t aspirate; it would be expected that a significant minority of these individuals would avoid aspiration and possibly be at lower risk for complicating pneumonia.
Aspiration of gastric fluid is quite common in near- drowning patients,
causing inflammatory damage in pulmonary parenchyma and contamination.
The chemical composition of the water certainly affects the type of pathogenic organism involved in the pulmonary infection,
but it is unknown if this factor affects the overall rate of infection [4].
We will describe 8 cases of near drowning evaluated in Pisa from July 2008 to September 2010.
2 cases are classified in stage 1,
while 6 cases are in stage 2- 3; we evaluate their evolution and complications (ARDS in 1 patient).
Chest radiography and CT images are evaluated.