TY  - JOUR
PY  - 2007//
TI  - Reduced cerebral perfusion on sudden immersion in ice water: a possible cause of drowning
JO  - Aviation, space, and environmental medicine
A1  - Belhage, Bo
A1  - Mantoni, Teit
A1  - Pott, Frank Christian
A1  - Pedersen, L. M.
SP  - 374
EP  - 376
VL  - 78
IS  - 4
N2  - INTRODUCTION: Near-drowning incidents and drowning deaths after accidental immersion in open waters have been linked to cold shock response. It consists of inspiratory gasps, hyperventilation, tachycardia, and hypertension in the first 2-3 min of cold-water immersion. This study explored the immediate changes in cerebral blood flow velocity (Vmean) during cold-water immersion since cold shock induced hyperventilation may diminish Vmean and lead to syncope and drowning. METHODS: There were 13 male volunteers who were lowered into a 0 degrees C immersion tank for 30 s. Vmean in the middle cerebral artery (MCA) was measured together with ventilatory parameters and heart rate before, during, and after immersion. RESULTS: Within seconds after immersion in ice water, heart rate increased from 74 +/- 16 to 107 +/- 18 bpm (mean +/- SD; p < 0.05). Immersion was associated with a marked elevation in respiratory rate (from 16 +/- 3 to 38 +/- 14 breaths x min(-1)) and tidal volume (883 +/- 360 to 2292 +/- 689 ml). The end-tidal carbon dioxide tension decreased from 38 +/- 4 to 26 +/- 5 mmHg and MCA Vmean dropped by 43 +/- 8%. Signs of imminent syncope (drowsiness, blurred vision, loss of responsiveness) were shown by two subjects (MCA Vmean dropped 62% and 68%, respectively). DISCUSSION: Following ice-water immersion, hyperventilation induced a marked reduction in MCA Vmean to a level which has been associated with disorientation and loss of consciousness.<p />  <p>Language: en</p>
LA  - en
SN  - 0095-6562
UR  - http://dx.doi.org/
ID  - ref1
ER  -