Facebook
Twitter
LinkedIn
Email
 |
Checking for direct PDF access through Ovid | |
Excerpt
Introduction: Individual response to CO poisoning varies and the percentage of CO hemoglobin does not correlate with the severity of the hypoxic tissue damage to the brain and heart. [1] Delayed neurological sequelae have been reported in untreated patients with low CO levels. [2,3] PSYTs assess individual psychomotor skill in patients exposed to CO, regardless of the CO blood level. We evaluated the usefulness of PSYTs as a tool for planning HBO re-treatments in patients with CO poisoning.
Methods: We retrospectively reviewed the medical record of 44 patients intoxicated with CO over the last 5 years. All patients were evaluated by a faculty psychologist after the first treatment, when the estimated COHb level was 0. Criteria for repeated treatment was lack of improvement or improvement with residual PSYT deficits. One treatment/day was scheduled and the patient re-evaluated after each treatment. Treatment was discontinued when patient performance reached a plateau (two consecutive dives without improvements) or PSYT results were compatible with the patient's social and educational background. Nonparametric statistical analysis was performed.
Results: Mechanisms of injury were heater (n = 17), suicide attempt (12), car (non-suicide, 7), generator (5), house fire (2), unknown (1). Mean age (+/- 1 SD) was 40.3 years (24.8); 26 (59%) were male. Exposure time to CO was 5.2 hours (2.9). Symptoms varied from headache to coma. Level of CO Hgb was 21.5% (10.2) measured at 3.1 hours (2.1) after exposure, usually drawn while breathing on a non-rebreather O2 mask. In 18 patients (41%) PSYTs were compatible with residual symptoms of CO intoxication. The number of dives necessary to return to estimated baseline or symptom plateau was a median of 1 (range 0 to 8. 25%-75% 1-2). The need for further treatments did not correlate with COHb, Hb level, or exposure time.
Discussion: PSYTs have been advocated as sensitive screening of silent CO poisoning, regardless of the blood level. Therefore, this screening method could be useful in detecting subtle mental change after initial HBO treatment. As long as the patient improves after re-treatments. PSYTs may be used to guide therapy. A limitation of this approach is the lack of pre-intoxication evaluation and the lack of control patients.
