Regimen of Alfentanil in Propofol Sedative Fibro-bronchoscopy

The Optimal Regimen of Alfentanil in Propofol Sedative Fibro-bronchoscopy：a Prospective Randomized, Double-blind, Placebo-controlled Trial

Alfentanil (Alf) is used in combination with Propofol (Pro) in fiber-bronchoscopy and in many other conscious sedation procedures. Alf and Pro have the characteristic of rapid anesthetic onset and quick recovery, synergic sedative effect and unwanted side effects too. However, the amount of Alf needed in combination with Pro for induction and the timing of administration was no standardized. The investigators designed this study to evaluate the optimal regimen, dose and timing of Alf in Target-Controlled infusion (TCI) of Pro for flexible bronchoscopy sedation, and also to evaluate the influence of variable regimen of Alf and Pro on hypoxemia, hypotension, cough severity, and Pro injection related pain.

Alfentanil (Alf) is used in combination with Propofol (Pro) in fiber-bronchoscopy and in many other conscious sedation procedures. Alf and Pro have the characteristic of rapid anesthetic onset and quick recovery, synergic sedative effect and unwanted side effects too. However, the amount of Alf needed in combination with Pro for induction and the timing of administration was no standardized. The investigators designed this study to evaluate the optimal regimen, dose and timing of Alf in Target-Controlled infusion (TCI) of Pro for flexible bronchoscopy sedation. Method: patients will be enrolled and assigned randomly into five groups. In group 1, normal saline two minutes before and Alf 2.5μg/kg before Pro were given; In group 2, normal saline two minutes before and Alf 5μg/kg before Pro were given; In group 3, Alf 2.5μg/kg two minutes before and normal saline before Pro were given; In group 4: Alf 5μg/kg two minutes before and normal saline before Pro were given; in group 5, normal saline two minutes and before Pro were given. Concentration of effect site to loss of consciousness (LOC), dose of Pro to LOC, and induction time of variable regimen, as well as hypoxemia, hypotension, cough severity, and Pro injection related pain will be recorded and analyzed.

Normal Saline (placebo comparator) was given in equivalent amount of alfentanil dosage in each arm, for double blinded purpose.

The Propofol dosage was according to the effect site concentration to reach OAAS-3 ( loss of conscious), using Schneider model

The Propofol dosage is according to the effect site concentration to reach OAAS-3 ( loss of conscious), using TCI Schneider model during the whole procedure of bronchoscope

After the administration of alfentanil and propofol, the effect site concentration was recorded at the time when the consciousness level reaches observer assessment of alertness and sedation scale 3 (OAAS-3). The effect site concentration is the concentration of drug propofol in brain calculated by TCI using Schnider model.

All participants wil be follow for the duration of bronchoscope room stay, an expect average of 2 hours

After the administration of Alfentanil and Propofol, the Propofol dose needed to reach conscious level of observer assessment of alertness and sedation scale 3 (OAAS-3) will be recorded.

All participants wil be follow for the duration of bronchoscope room stay, an expect average of 2 hours

After the administration of Alfentanil and Propofol, the time period required to reach conscious level OAAS-3 will be recorded.

All participants wil be follow for the duration of bronchoscope room stay, an expect average of 2 hours

All participants wil be follow for the duration of bronchoscope room stay, an expect average of 2 hours

All participants wil be follow for the duration of bronchoscope room stay, an expect average of 2 hours

Inclusion Criteria: patients who required elective sedative bronchoscopy Exclusion Criteria: any physical, psychiatric, social problem that avoid from conscious level evaluation, hypersensitivity or allergy to Propofol, Alfentanil severe chronic obstructive pulmonary disease (forced expiratory volume in 1 s ,50% of predicted value, or requirement for oxygen therapy) unstable haemodynamic status (defined as a heart rate < 60 or ≧ 120 bpm and/or a systolic blood pressure (SBP) < 100 or ≧ 180 mmHg) predictable difficult upper airways (Mallampati classification score of IV) severe obstructive sleep apnea with apnea hypopnea index (AHI) > 45 Body mass index (BMI) more than 42 in male and 35 in female renal insufficiency liver cirrhosis