Electroencephalographic studies of survival following hypothermic hypoxia in developing chicks

✍ Scribed by Peters, Joseph J. ;Bright, Thomas P. ;Vonderahe, Alphonse R.

• Book ID: 102889834
• Publisher: John Wiley and Sons
• Year: 1968
• Tongue: English
• Weight: 886 KB
• Volume: 167
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1401670206

✦ Synopsis

In chicks between the day of hatching and ten days after hatching the body temperature was lowered from normal to either 34OC or 24°C. Oxygen was then replaced by nitrogen until breathing ceased and the electroencephalograms of the cerebral lobes were reduced to no difference of potential. When this zero potential had endured for a period four times as long as that which yielded about 50% recovery in one to ten day chicks at normal body temperature, artificial ventilation was applied for a maximum of eight minutes or until the onset of spontaneous breathing. This fourfold duration of zero potential was: 12 minutes for newly hatched and one day chicks, six minutes for five day chicks, and four minutes for ten day chicks. A withholding of artificial respiration for these prolonged periods of zero potential resulted in the following percentages of recovery: at normal body temperatures, 0 % ; at 34°C and 24°C respectively, newly hatched chicks 23% and 90%, one day chicks 10% and 40%, five day chicks 40% and 70%, ten day chicks 80% and 90%. Prior to artificial resuscitation birds had electrocardiograms indicating irregular beats, various degrees of heart block, and cardiac arrest for as long as seven minutes; some of these recovered. The transition of the electroencephalogram from zero potential to normal EEG patterns was characterized by a gradual increase in amplitude of both slow and fast waves in the younger chicks and a kind of steplike recovery in the older birds. During recovery about 50% of the younger chicks showed seizures resembling "petit mal." After a recovery period of 4 to 24 hours the surviving chicks showed no behavioral abnormalities.