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Scientific References

Accelerated Clearance of Volatile Anesthetics by ClearMate™

KATZNELSON, R., MINKOVICH, L., FRIEDMAN, Z., FEDORKO, L., BEATTIE, W.S., & FISHER, J.A. Accelerated recovery from sevoflurane anesthesia with isocapnic hyperpnoea. Anesth Analg 106: 486-91, 2008.
Postoperative recovery variables of patients undergoing elective gynecological surgery under sevoflurane anesthesia in air/O2 recovered in the customary fashion (control group) were compared to those given isocapnic hyperppnea (IH) at the end of surgery. Time to tracheal extubation was significantly shorter in the IH group compared with group C (6.2 vs 12.3 min, respectively) as were time to initiation of spontaneous ventilation (4.2 vs 6.5 min), eye opening (5.5 vs 13.3 min), bispectral index value >75 (3.9 vs 8.8 min), leaving operating room (7.7 vs 15.3min), and eligibility for post-anesthetic care unit discharge (67.2 vs 90.6 min). IH accelerates recovery from sevoflurane anesthesia and shortens operating room and post-anesthetic care unit stay.
KATZNELSON, R., VAN, R.A., FRIEDMAN, Z., WASOWICZ, M., DJAIANI, G.N., FEDORKO, L., MINKOVICH, L., & FISHER, J.A. Isocapnic hyperpnoea shortens postanesthetic care unit stay after isoflurane anesthesia. Anesth Analg 111: 403-408, 2010.
This was a prospective controlled clinical trial of the effect of isocapnic hyperpnoea (IH) on the times-to-recovery milestones in the operating room (OR) and post-anesthetic care unit (PACU) after 1.5 to 3 h of isoflurane anesthesia. Thirty ASA grade I-III patients undergoing elective gynecological surgery were randomized at the end of surgery to either IH or the conventional recovery (control). The durations of anesthesia in IH and control groups averaged 141 and 142 min, respectively. The time to extubation was much shorter in the IH group than in the control group (6.6 vs 13. 6 min). The IH group also had shorter times to eye opening (5.8 vs 13.7 min), eligibility for leaving the OR (8.0 vs 17.4 min), and eligibility for PACU discharge (74.0 vs 94.5 min).
KATZNELSON, R., NAUGHTON, F., FRIEDMAN, Z., LEI, D., DUFFIN, J., FEDORKO, L., WASOWICZ, M., VAN, R.A., MURPHY, J., & FISHER, J.A. Increased lung clearance of isoflurane shortens emergence in obesity: a prospective randomized-controlled trial. Acta Anaesthesiol Scand 55: 995-1001, 2011.
To test the hypothesis that increased pulmonary clearance of isoflurane shortens immediate recovery from anesthesia and post-anesthesia care unit (PACU) stay in obese patients, 44 ASA I-III patients with BMI >30 kg/m2 undergoing elective gynecological or urological surgery were randomized after completion of surgery to either an isocapnic hyperpnoea (IH) or a conventional recovery (C) group. Minute ventilation in the IH group before extubation was 23 vs. 6.3 l/min in the C group. The IH group had a shorter time to extubation (5.4 vs 15.8 min), initiation of spontaneous ventilation (2.7 vs 6.5 min), BIS recovery >75 (3.2 vs 8.9 min), eye opening (4.6 vs 13.6 min) and eligibility for leaving the operating room (7.1 vs. 19.9 min). There was no difference in time for eligibility for PACU discharge.
KATZNELSON R1, DJAIANI G, NAUGHTON F, WASOWICZ M, RAGOONANAN T, DUFFIN J, FEDORKO L, MURPHY J, FISHER JA. Post-operative hypercapnia-induced hyperpnoea accelerates recovery from sevoflurane anaesthesia: a prospective randomised controlled trial. Acta Anaesthesiol Scand. 57: 623-30, 2013.
Because hypercapnia increases anesthetic clearance from the brain by increasing cerebral blood flow, the authors tested the hypothesis that hypercapnia-induced hyperpnoea, compared to the standard protocol, accelerates emergence from sevoflurane anesthesia. Patients undergoing elective gynecological surgery were randomised after surgery to either hypercapnic hyperpnoea or control groups. In the hypercapnic hyperpnoea group, the end-tidal CO2 was adjusted to a range of 6.0-7.3 kPa (45 – 55 mmHg) to maintain a minute ventilation of 10-15 l/min. Prior to extubation, minute ventilation and end-tidal CO2 in hypercapnic hyperpnoea and control groups averaged 10.3 vs 5.4 l/min and 6.6 vs 5.2 kPa (50 vs 35 mmHg), respectively. Compared to control, the hypercapnic group had shorter time to extubation (4.4 vs 9.8 min), BIS recovery to > 75 (2.4 vs 6.1 min), eye opening (3.9 vs 9.8 min), eligibility for leaving the OR (5.1 vs.11.1 min) and the PACU (73.9 vs 89.4 min).