Seasonal H3N2 influenza A virus fails to enhance Staphylococcus aureus co-infection in a non-human primate respiratory tract infection model.

We studied the relationship between parasympathetic, sympathetic and pituitary-adrenal functions in chronic schizophrenic patients with complications such as postoperative paralytic ileus and hypotension during anaesthesia. Plasma epinephrine, norepinephrine (NE), adrenocorticotropin (ACTH), cortisol and the coefficient of variation (CV) of the R-R intervals on the electrocardiogram (ECG) as parasympathetic parameter were measured in schizophrenic and control patients. The CV value of the R-R interval on the ECG before the start of anaesthesia was significantly decreased to 2.3 +/- 0.2 in the schizophrenic patients as compared with 3.5 +/- 0.3 of the control patients. The CV value of the R-R interval on the ECG in schizophrenic patients with postoperative paralytic ileus was more diminished to 1.6 +/- 0.2. The CV values in schizophrenic patients with and without hypotension during anaesthesia were similar and we could not find any significant difference. Chronic schizophrenic patients developed a decrease in NE, ACTH and cortisol responses to surgical stress, while there were no significant differences in these hormonal changes between those patients with and without paralytic ileus and hypotension during anaesthesia. In conclusion, the CV value of the ECG R-R interval may be correlated inversely with the expectancy of postoperative ileus in chronic schizophrenic patients. Their suppressed pituitary-adrenal function and sympathetic system may be indirectly associated with the paralytic ileus and hypotension.