Table 3. Early Postoperative Recovery and Effects of Different Types of Intravenous Opioids [7, 10, 18-23, 30].

Studies	Drugs	Clinical variables	Results
Guy et al, 1997 [10]	Remifentanil vs. fentanyl	ET Quality of recovery	No statistical difference Low recovery score within 60 min more in fentanyl group Naloxone use more in fentanyl group
Citerio et al, 2012 [23]	Sevoflurane/remifentanil vs. sevoflurane/fentanyl vs. propofol/remifentanil	Aldrete score	No statistical difference
Gerlach et al, 2003 [18]	Remifentanil/propofol vs. sufentanil IV pushes/propofol	ET	Remifentanil group had earlier ET 6.4 min vs. 14.3 min (P = 0.003)
Balakrishnan et al, 2000 [19]	Remifentanil vs. fentanyl	ET (P = 0.04) Obay commands (P < 0.001) ET (P = 0.04) Recovery in 10 min (P = 0.005) Recovery in 20 min	Better in remifentanil group No statistical difference
Van der Zwan et al, 2005 [22]	Remifentanil/piritramide vs. fentanyl	GCS Aldrete score	No statistical difference
Del Gaudio et al, 2006 [7]	Remifentanil vs. fentanyl	ET Obey commands Orientationx3 Aldrete score	Remifentanil group faster (P < 0.001)
Djian et al, 2006 [20]	Remifentanil vs. sufentanil	ET	No statistical difference
Bilotta et al, 2007 [21]	Remifentanil vs. sufentanil	ET SOMCT	No statistical difference Higher in remifentanil group (P < 0.0001)
From et al, 1990 [30]	Alfentanil vs. fentanyl vs. sufentanil	Alertness	More in alfentanil group

ET: extubation time; GCS: Glasgow coma scale; SOMCT: short orientation memory concentration test.