Page 1856 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 132: Diving Medicine and Drowning 1325

■ NEUROLOGICAL CONSIDERATIONS

Special measures for brain resuscitation in drowning are of historical
interest, but none have been shown to improve outcome. The problem
is difficult to study because so many diverse parameters influence brain
injury and recovery, including young age, submersion time (and water
temperature), coexisting injuries, and preexisting disease. The issue is
70
further complicated by anecdotes of complete or nearly complete neu-
rologic recovery in association with uncontrolled therapeutic modalities
after prolonged submersion, such as barbiturates, corticosteroids, manipu-
lation of intracranial pressure (ICP) and mild hypothermia. The neuro-
logical status at 1 to 2 hours post-resuscitation is perhaps the best indicator
of long-term neurological outcome, but the prognostic uncertainties about
brain recovery after drowning mandate a full effort at cardiopulmonary
resuscitation, including the correction of hypothermia. 42,71,72
A classification system with reasonable discrimination for outcome
classifies patients after resuscitation into three categories, as listed in
Table 132-3. 50,51 The best discrimination for outcome with this system has
been found in children in whom all category A and B patients (n = 57)
recovered completely. Level C patients (n = 39) had 33.3% and 23.9%
cerebral morbidity rates (mortality rate + morbidity rate = 56.2%), with
the lowest survival rate in the C.3 group. In another series of patients
51
that included 52 adults, the category A patients recovered completely,
FIGURE 132-3. Chest radiograph 2 hours after an episode of near drowning shows and two adults and one child in level B eventually succumbed to baro-
typical patchy opacities.
50
trauma or other complications. Eight of 11 (73%) adult and 8 of 18
(44%) child category C patients recovered completely in that series.
with intrapulmonary shunting are encountered in all types of drowning A management regimen known as HYPER (hyperhydration, hyper-
and ARDS can develop. Although there are no randomized controlled pyrexia, hyperexcitability, and hyperrigidity) initially suggested some
51
trials in this population of patients specifically, these individuals should benefit in children seriously injured by drowning. The acronym refers
be treated, like other instances of ARDS, with PEEP and lung protective to the overhydration, fever, excitability, and muscular rigidity thought to
ventilation (TV 6 mL/kg ideal body weight and plateau pressure <30 cm negatively affect outcome in some patients.
H O; see Chap. 52). The improvement in severe hypoxemia after drown- HYPER therapy consisted of corticosteroids, osmotic diuretics,
2
ing with the use of PEEP to decrease intrapulmonary shunt can be dra- hyperventilation, barbiturate coma, and muscle relaxants administered
matic. Deep sedation or muscle relaxants are best avoided because they to minimize cerebral edema and decrease ICP. Controlled hypothermia
52
impair the ability to follow the neurologic examination. The judicious (32°C, 89.6°F) to decrease neuronal metabolism was advocated. ICP
use of these agents may facilitate mechanical ventilation by synchroniz- monitoring is necessary to guide such aggressive therapy. The rationale
ing the patient with the ventilator and by decreasing airway pressures for HYPER therapy was based on the idea that control of ICP would
and the risk of barotrauma. The use of sedation holidays and spontane- minimize neuronal damage after diffuse anoxia. As mentioned earlier,
ous breathing trials is recommended. Treatment of children with drown- increases in ICP may be a result of severe neuronal injury rather than
ing and ARDS with artificial surfactant does not improve outcome, but its cause.
did modestly improve pulmonary function. 68 Subsequent experience with HYPER therapy failed to confirm its
efficacy and highlighted its detrimental effects. 41,42,73 A retrospective
Pulmonary Complications: Respiratory insufficiency may be complicated review of 40 patients from the institution that reported the original
by factors other than atelectasis and intrapulmonary shunt. Airway experience with HYPER found increased incidences of sepsis and
obstruction may occur as bronchospasm or by the presence of a multiple organ failure in patients treated with hypothermia. This may
foreign body in the airway. Bronchodilator therapy may benefit the result from cold-induced immune suppression (including neutropenia)
patient with diffuse wheezing. Patients with localized atelectasis that complicated by cold-induced bronchorrhea and decreased mucociliary
fails to improve with effective ventilation or those who exhibit local- clearance. 70
ized wheezing should undergo fiberoptic bronchoscopy to exclude or Since corticosteroids have no proven benefit in decreasing brain
remove a foreign body. edema in drowning, they should be avoided because they are immu-
Pneumonia is a common complication of drowning and may be nosuppressive and predispose to infection and gastric ulceration. 41,42
related to submersion in contaminated water or to a prolonged need Although hypothermia and barbiturates can decrease ICP in some cir-
for mechanical ventilation. Many drowning accidents occur in water cumstances, their use does not improve neurologic outcome. Osmotic
contaminated with human or animal waste or naturally containing agents also do not improve neurologic outcome in drowning and may
pathogenic bacteria or fungi. The lung is the usual portal of entry for lead to hyperosmolarity and renal insufficiency. Mild hyperventilation
these organisms. Infection is heralded by fever 2 to 7 days after the
event and should prompt sputum and blood cultures before initiation of
antibiotic therapy. 64,69 Prophylactic antibiotic coverage has not improved TABLE 132-3 Classification of Individuals After Near Drowning and Initial
outcome in drowning, and routine use of antibiotics, unless immer- Resuscitation
sion in raw sewage is involved, is not indicated. Unusual organisms Category A Awake, fully conscious
may occur in fresh or salt water and the reports include Klebsiella oxy- Category B Blunted consciousness, stuporous but arousable
toca, Herellea species, Neiserria meningitides, Pseudomonas aeruginosa,
Listeria monocytogenes, Plesiomonas shigelloides, Chromobacterium Category C Comatose
violaceum, Aeromonas hydrophila, Proteus mirabilis, and Vibrio parahe- C.1 Decorticate posturing
molyticus. Awareness of infection by such organisms is crucial because C.2 Decerebrate posturing
they may have specific culture requirements not routinely offered in
many hospital microbiology laboratories. C.3 Flaccid

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