During the same period the blood pressure, heart rate, ECG, SpO2 will be measured to evaluate cardiovascular, respiratory function, and the patient evaluated for nausea/vomiting, shivering and any neurological abnormalities. Episodes of hypotension (mean blood pressure less than 50 mmHg for a period greater than 5 minutes), hypertension (meant blood pressure greater than 100 mmHg for a period greater than 5 minutes) will be recorded and treated if necessary.