Reduction of pain on injection of propofol: combination of pretreatment of remifentanil and premixture of lidocaine with propofol

BACKGROUNDS AND OBJECTIVE: There is a high incidence of pain following intravenous injection of propofol, and many studies have been conducted to find a way of reducing this. The administration of lidocaine and, recently, remifentanil has also been used for this purpose, but it is only partially effective. Thus, the purpose of this study was to investigate the analgesic effect of a combination of pretreatment with remifentanil and premixture of lidocaine with propofol and to compare either treatment alone during propofol injection in dorsal hand-veins. METHODS: In a prospective, randomized, double-blinded trial, we studied 141 adult patients scheduled for elective surgery. The combination of pretreatment of remifentanil (0.35 microg kg(-1) min(-1)) and a premixture of lidocaine with propofol (mixture of propofol 1% and lidocaine 1% in a 10:1 ratio) was compared with either treatment alone in the prevention of pain on propofol injection. Pain was assessed on a four-point scale (0=none, 1=mild, 2=moderate, 3=severe) during propofol injection. Patients in Group B received remifentanil (0.35 microg kg(-1) min(-1)) 30 s before the injection of propofol. RESULTS: The reduction of pain on propofol injection was similar in both the remifentanil pretreatment and lidocaine premixture groups (62.2% vs. 62.2%). Combination therapy was associated with a higher incidence of patients without pain (91.3%) than either treatment alone (P<0.001). On analysing the injection pain scores, we found a significant reduction of the score in the remifentanil and lidocaine Group C compared with the lidocaine Group A (P<0.001) and the remifentanil Group B (P<0.001). CONCLUSIONS: The combination of pretreatment of remifentanil and premixture of lidocaine with propofol was more effective in reducing the incidence of pain on injection of propofol than either treatment alone.     

Remifentanil administration during monitored anesthesia care: are intermittent boluses an effective alternative to a continuous infusion?

This randomized, double-blind study was designed to evaluate the analgesic effectiveness and respiratory stability of remifentanil when administered as intermittent bolus injections, a variable-rate infusion, or a combination of a constant basal infusion supplemented with intermittent boluses during monitored anesthesia care (MAC). Forty-five patients undergoing extracorporeal shock wave lithotripsy (ESWL) procedures were randomly assigned to one of the three modes of remifentanil administration. All patients received midazolam 2 mg i.v., followed by a propofol infusion at 50 microg x kg(-1) x min(-1). Two minutes before administering a series of test shock waves: Group I received a remifentanil infusion of 0.1 microg x kg(-1) x min(-1), and a saline bolus (5 mL); Group II received a saline infusion and a remifentanil bolus (25 microg in 5 mL); and Group III received a remifentanil infusion of 0.05 microg x kg(-1) x min(-1), and a remifentanil bolus (12.5 microg in 5 mL). The average pain intensity was scored on an 11-point scale, with 0 = no pain to 10 = severe pain. During the ESWL procedure, pain was treated by increasing the study drug infusion rate by 25%-50% and administering 5-mL bolus injections of the study medication in Groups I (saline) and II (remifentanil 25 microg). In Group III, intermittent 5-mL boluses (remifentanil 12.5 microg) were administered as needed. Patients in Groups II and III reported lower pain scores in response to the test shocks. Significantly more remifentanil was administered in Group I (379 +/- 207 microg) than in Group II (201 +/- 136 microg). However, more interventions were required for the treatment of intraoperative pain in the intermittent bolus group (Group II). When remifentanil is administered as the analgesic component of a MAC technique, these data support the use of intermittent bolus doses (12.5-25 microg) alone or in combination with a basal infusion (0.05 microg x kg(-1) x min(-1)) as alternatives to a variable-rate continuous infusion. IMPLICATIONS: In this study, three different modes of remifentanil administration were used during monitored anesthesia care for extracorporeal shock wave lithotripsy procedures. These results suggest that using intermittent bolus injections of remifentanil (25 microg) or a continuous infusion (0.05 microg x kg(-1) x min(-1)) supplemented with intermittent bolus (12.5 microg) injections may be more effective than a variable-rate infusion of remifentanil during propofol sedation.     

Tracheal intubation of outpatients with and without muscle relaxants

PURPOSE: To compare intubating conditions and postoperative myalgias in outpatients after intubation with propofol/alfentanil compared with propofol/alfentanil/succinylcholine with and without precurarisation with d-tubocurarine. METHODS: 144 ASA I-II ambulatory patients for dental extraction under anesthesia were studied. Subjects received either 3 mg d-tubocurarine (Group II) or saline (Groups I, III) i.v. prior to induction of anesthesia with 20 microg x kg(-1) alfentanil and 2.5 mg x kg(-1) propofol followed by 1.5 mg x kg(-1) succinylcholine (II and III) or saline 0.9% (I) for muscle relaxation. The ease of airway management and the postoperative incidence, severity and distribution of muscle pains were examined. RESULTS: Intubation was successful in all patients and there were no differences in jaw mobility, ease of bag-mask ventilation, visualization of the vocal cords or cord position. Limb movement was more common during intubation in Group I (37.5%) than in Group III (8.3%) or Group II (2%), P < 0.05. At home, VAS scores for myalgia were higher in Group III than in Group I and II. Neck myalgia was more common in Group II (72%) than in Groups II (44%) and I (41%), P < 0.05. Myalgias were also more common in Group III patients (P < 0.05). CONCLUSION: Acceptable intubating conditions were achieved with propofol and alfentanil alone. Succinylcholine reduced limb movement during intubation but was associated with postoperative myalgias for up to five days. Precurarisation with tubocurarine reduced the severity of succinylcholine myalgia.     

Effects of concentration and dosage of lidocaine on preventing the pain on injection of propofol

Although it is well-known that 2% lidocaine has an effective action for preventing propofol-induced pain, it has been unclear whether or not lidocaine of the concentration below 2% has the effective action similar to 2% lidocaine. One-hundred and thirty-two patients were randomly assigned to one of the six groups according to concentration and dosage of lidocaine administered at the time of the initiation of propofol infusion. Groups I and II received 1 ml and 2 ml of 1% lidocaine, respectively; Groups III and IV were given 1 ml and 2 ml of 0.5% lidocaine, respectively; Group V received 2 ml of 2% lidocaine; Group VI was administered 1 ml of normal saline as a control. There were no significant differences in patients' profiles and alterations of hemodynamics during anesthetic induction among the six groups. Number of patients complaining of a pain during induction was more in Group VI with significance (P < 0.0001) and number of patients complaining of uncomfortableness was also more with significance (P < 0.0001). Incidence of propofol-induced pain and degree of satisfaction with anesthetic induction were similar among the groups receiving lidocaine. Even 0.5% lidocaine may have the same effective action as 2% lidocaine for preventing the pain on injection of propofol.     

Epidural anesthesia with lidocaine reduces propofol injection pain

PURPOSE: To determine whether epidural lidocaine reduces the severity of propofol injection pain compared with iv lidocaine. METHODS: A prospective, randomized double-blind clinical study was conducted in 120 female patients scheduled for elective gynecological laparotomy. A lumbar epidural catheter and an iv catheter placed in the cephalic vein of the non-dominant hand were used in all patients. Patients of the control group (Group C) were given epidural normal saline followed by iv normal saline then iv propofol. Patients of Group E were given epidural 2% lidocaine (0.08 mL.cm(-1)) followed by iv normal saline and then propofol. Patients of Group V were given epidural normal saline followed by iv 2% lidocaine (0.05 mL.kg(-1)) then propofol. Pain was scored as no pain=0, minimal pain=1, moderate pain=2, severe pain=3. RESULTS: The pain scores, in group E; 1 (0-2) and group V; 2 (0-2), were significantly lower than in group C; 2 (1-3); median (25th-75th percentile) (P <0.001). There was no difference in pain score between groups E and V The plasma lidocaine concentration 15 min after epidural lidocaine was 2.74 +/- 0.54 microg.ml(-1), compared with 1.54 +/- 0.31 microg.mL(-1) at three minutes after iv lidocaine. CONCLUSION: Epidural and iv lidocaine equally reduced the severity of propofol injection pain despite higher lidocaine plasma concentrations in epidurally administered lidocaine.     

Remifentanil and propofol sedation for retrobulbar nerve block

We studied remifentanil and propofol for analgesia and sedation during the placement of an ophthalmic block. Eighty ASA I or II patients undergoing elective cataract surgery under a retrobulbar block in a rural camp setting were included in the study. Patients were randomly divided into four groups and received different drug combinations as follows: Group I--remifentanil 1 microg/kg, Group II--remifentanil 0.5 microg/kg and propofol 0.5 mg/kg, Group III--remifentanil 1 microg/kg with propofol 0.5 mg/kg and Group IV--saline 0.1 ml/kg. Patients were observed for degree of movement, sedation, pain, recall and respiratory depression. No patient in the study groups reported pain or displayed movement whereas most of the patients in the control group had significant pain during the placement of the block. Also, seven (35%) patients in the control group showed significant movement which may have led to failure of block in two patients and retrobulbar haemorrhage in one patient. Incidence of significant respiratory depression was maximum in Group III patients (60%), followed by Group I (20%) and least in Group II (5%). All patients in the study groups remained cooperative and obeyed commands except four patients in group III (OAA/S-4). Postoperatively, other than the control group, recall was maximum in Group I (55%) and least in Group II (5%). Hence, a combination of remifentanil 0.5 microg/kg with propofol 0.5 mg/kg as a bolus was considered to provide excellent relief of pain and anxiety with least adverse effects for the placement of ophthalmic blocks.     

Comparison of hemodynamics,recovery profile,and early postoperative pain control and costs of remifentanil versus alfentanil-based total intravenous anesthesia (TIVA)

STUDY OBJECTIVE: To compare hemodynamics, recovery profiles, early postoperative pain control and costs of total intravenous anesthesia (TIVA) with propofol and remifentanil and propofol and alfentanil. DESIGN: Randomized, double-blind study. SETTING: University hospital. PATIENTS: 40 ASA physical status I and II adult patients scheduled for lumbar discectomy. INTERVENTIONS: Patients were randomly assigned to receive either remifentanil-propofol or alfentanil-propofol. Anesthesia was induced with remifentanil 1 microg kg(-1) or alfentanil 20 microg kg(-1) with propofol 2 mg kg(-1), and maintained with infusions of propofol 150 to 100 microg kg(-1)min(-1) and either remifentanil 0.1 microg kg(-1) min(-1) or alfentanil 0.5 microg kg(-1) min(-1). MEASUREMENTS: Hemodynamic parameters (heart rate and mean arterial pressure), times to awakening, and tracheal extubation were recorded. In the postanesthesia care unit, pain level, frequency of analgesic demand, frequency of postoperative nausea and vomiting (PONV), partial oxygen saturation (SpO2), and respiratory rates were noted. Drug dosages and costs of each technique were determined. MAIN RESULTS: The mean arterial pressure significantly decreased compared to baseline values 1 minute after induction (p < 0.05) in both groups, and it significantly decreased at 5, 15, and 30 minutes perioperatively in the remifentanil group compared to the alfentanil group (p < 0.05). Time of extubation, spontaneous eye opening, and response to verbal command were similar in both groups. Visual analog scale pain scores at 30 minutes and 60 minutes were significantly lower in the alfentanil group than remifentanil group (p < 0.05). At 15, 30, and 60 minutes after terminating the operation oxygen saturation and respiratory rate were significantly higher (p < 0.05) and analgesics were required sooner in the remifentanil group than the alfentanil group (p < 0.05). The frequency of PONV was similar in both groups. The remifentanil-propofol anesthesia was found to be slightly more expensive as compared to the alfentanil based TIVA (33.41 +/- 4.53 vs. 29.97 +/- 4.1 USD) (p < 0.05). CONCLUSIONS: Both remifentanil and alfentanil provided a reasonably rapid and reliable recovery. The remifentanil-based TIVA was associated with high intraoperative cost and early postoperative pain, but it allowed a more rapid respiratory recovery.     

Pain during injection of propofol: the effect of prior administration of butorphanol

Propofol causes pain or discomfort on injection in 28%-90% of patients. A number of techniques have been tried for minimizing propofol-induced pain with variable results. We compared the efficacy of butorphanol and lidocaine for prevention of propofol-induced pain. One-hundred-fifty ASA I-II adults, undergoing elective surgery were randomly assigned into 3 groups of 50 each. Group I (NS) received normal saline, Group II (L) received lidocaine 2% (40 mg), and Group III (B) received butorphanol 2 mg. All patients received pretreatment solutions made in 2 mL with normal saline administered over 5 s. One min after pretreatment patients received one-fourth of the total calculated dose of propofol (2.5 mg/kg) over 5 s. Assessment of pain with IV propofol was done by using a four-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain and 3 = severe pain at the time of propofol injection. In the control Group 39 (78%) patients had pain during propofol injection as compared to 21 (42%) and 10 (20%) in the lidocaine and butorphanol groups, respectively (P < 0.05). Butorphanol was the most effective. We therefore suggest the IV pretreatment with butorphanol 2 mg for attenuation of pain associated with propofol injection.     

A combination of alfentanil-lidocaine-propofol provides better intubating conditions than fentanyl-lidocaine-propofol in the absence of muscle relaxants

PURPOSE: To compare the ease of tracheal intubation without the use of muscle relaxants following an alfentanil-lidocaine-propofol sequence vs a fentanyl-lidocaine-propofol sequence. CLINICAL FEATURES: In 80 ASA I and II adult patients undergoing elective laparoscopic surgery, we compared the intubating conditions following alfentanil 20 microg x kg(-1), lidocaine 1.5 mg x kg(-1), propofol 3 mg x kg(-1) (Group I; n = 40) vs fentanyl 2 microg x kg(-1), lidocaine 1.5 mg x kg(-1), propofol 3 mg x kg(-1) (Group II; n = 40). The intubating conditions were scored by jaw relaxation, vocal cord position and response to intubation, as well as by blood pressure and heart rate changes. The intubating conditions were good or excellent in 95% of patients in Group I vs 62.5% of patients in Group II (P < 0.05). Blood pressure decreased from a preinduction value of 86 +/- 13 mmHg to 72 +/- 28 mmHg and 74 +/- 19 mmHg in Group I, and from 85 +/- 12 mmHg to 78 +/- 15 mmHg and 78 +/- 12 mmHg in Group II, one and five minutes following intubation (P < 0.05). This drop in blood pressure was not different between the two groups. CONCLUSION: An alfentanil-lidocaine-propofol sequence offers significantly better intubating conditions than a fentanyl-lidocaine-propofol sequence in healthy adult patients.     

Propofol — not thiopental or etomidate — with remifentanil provides adequate intubating conditions in the absence of neuromuscular blockade

PURPOSE: Administration of remifentanil followed by propofol provides adequate conditions for tracheal intubation without muscle relaxants. Other hypnotic drugs have not been thoroughly investigated in this regard. Intubating conditions with remifentanil followed by propofol, thiopentone or etomidate are compared in this study. METHODS: In a randomized, double-blind study 45 healthy males were assigned to one of three groups (n = 15). After iv atropine, remifentanil 3 microg x kg(-1) were injected over 90 sec followed by propofol 2 mg x kg(-1) (Group I), thiopentone 6 mg x kg(-1) (Group II) or etomidate 0.3 mg x kg(-1) (Group III). Ninety seconds after the administration of the hypnotic agent, laryngoscopy and intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of ventilation, jaw relaxation, position of the vocal cords, and patient response to intubation and slow inflation of the endotracheal tube cuff. RESULTS: One patient in Group I, three patients in Group II and five patients in Group III could not be intubated on the first attempt. Clinically acceptable intubating conditions were observed in 93.3%, 66.7%, 40.0% of patients in Groups I, II and III, respectively. Overall conditions at intubation were significantly (P < 0.05) better, and the frequency of excellent conditions was significantly (P < 0.05) higher in the propofol group compared with the thiopentone and etomidate groups. No patient was treated for hypotension or bradycardia. CONCLUSION: Propofol 2 mg x kg(-1) was superior to thiopentone 6 mg x kg(-1) and etomidate 0.3 mg x kg(-1) for tracheal intubation when combined with remifentanil 3 microg x kg(-1) and no muscle relaxant.     

The effects of alfentanil or remifentanil pretreatment on propofol injection pain

STUDY OBJECTIVE: To compare the efficacy of alfentanil, remifentanil, and saline in minimizing the propofol injection pain. DESIGN: Randomized, double-blind study. SETTING: University hospital. PATIENTS: 175 ASA physical status I and II, adult female patients undergoing minor gynecological procedures with general anesthesia. INTERVENTIONS: Unpremedicated patients were randomly allocated to one of four groups. Patients received 2 mL (1 mg) of alfentanil (n=43), 2 mL of remifentanil 0.01 mg (n = 43), 2 mL of remifentanil 0.02 mg (n=45), or 2 mL of saline (n=44) 30 seconds prior to administration 5 mL of propofol 1%. MEASUREMENTS: Patients were asked whether they had pain due to propofol injection. Their pain scores were evaluated with a Visual Analogue Scale. In the Postanesthesia Care Unit, frequency of postoperative nausea, vomiting, hypotension, and flushing were all determined. MAIN RESULT: The remifentanil and alfentanil groups showed significantly less frequency and severity of pain than the saline group (p <0.05). When the alfentanil group was compared with the remifentanil groups, significant differences in pain relief associated with injection of propofol (p <0.001) were noted. Remifentanil 0.02 mg relieved pain associated with injection of propofol more effectively than remifentanil 0.01 mg (p <0.001). CONCLUSIONS: The remifentanil and alfentanil groups showed significantly less frequency and severity of pain than did the saline group. Remifentanil was effective in preventing propofol injection pain, and should be used at a dose of at least 0.02 mg for this purpose. Remifentanil may be an alternative drug for prevention of propofol injection pain.     

Intravenous lidocaine and ephedrine, but not propofol, suppress fentanyl-induced cough

PURPOSE: The aim of this study was to evaluate the effectiveness of lidocaine, propofol and ephedrine in suppressing fentanyl-induced cough. METHODS: One hundred and eighteen patients were randomly assigned into four groups and the following medications were given intravenously: patients in Group I (n = 31) received normal saline 2 mL, Group II (n = 29) received lidocaine 2 mg.kg(-1), Group III (n = 30) received propofol 0.6 mg.kg(-1) and Group IV (n = 28) received ephedrine 5 mg. At one minute after the study medication, fentanyl 2.5 microg.kg(-1) was given intravenously within two seconds. The occurrence of cough and vital sign profiles were recorded within two minutes after fentanyl bolus by an anesthesiologist blinded to study design. RESULTS: Sixty-five percent of patients in the placebo group had cough, whereas the frequency was significantly decreased in Groups II (14%) and IV (21%). Although a numerically lower frequency of cough was noted in Group III (37%), it was not statistically different from that of the placebo group. SpO(2) decreased significantly in patients of Group III compared to placebo; one patient experienced hypoxemia necessitating mask ventilation. Patients in Group III showed a decrease in heart rate and systolic blood pressure (2 beats.min(-1) and 8 mmHg vs baseline). Patients in Group IV showed an increase in both measurements (5 beats.min(-1) and 8 mmHg vs baseline). No truncal rigidity was observed throughout the study. CONCLUSIONS: Intravenous lidocaine 2 mg.kg(-1) or ephedrine 5 mg, but not propofol 0.6 mg.kg(-1), was effective in preventing fentanyl-induced cough. The results provide a convenient method to decrease fentanyl-induced cough.     

Efficacy of simultaneous bolus injection of lidocaine with propofol on pain caused by propofol injection]

To investigate the effect of simultaneous bolus injection of 2% lidocaine 2 ml on preventing the pain on propofol injection, 80 patients were randomly assigned to one of four study groups; Group I received simultaneous bolus injection of 2% lidocaine 2 ml with infusion of propofol; Group II received bolus injection of saline 2 ml, 10 s before the start of infusion of propofol-lidocaine mixture; Groups III and IV received bolus injections of lidocaine and saline, separately 10 s before starting propofol infusion. Incidence of propofol-induced pain was significantly more frequent (P < 0.001) in Group IV (70%) than in the other groups (20% each). Number of patients who were satisfied with this anesthetic induction and requested for the same induction method in the next anesthesia was significantly larger in the groups receiving lidocaine (P < 0.05). Simultaneous bolus injection of lidocaine with propofol showed a similar clinical efficacy compared with both preadministration and premixing of lidocaine in preventing the propofol-induced pain.     

Pretreatment with thiopental for prevention of pain associated with propofol injection

Propofol causes pain on IV injection in 28%-90% of patients. A number of techniques have been tried to minimize propofol-induced pain, with variable results. We compared the efficacy of pretreatment with thiopental 0.25 mg/kg and 0.5 mg/kg and lidocaine 40 mg after venous occlusion for prevention of propofol-induced pain. One-hundred-twenty-four adult patients, ASA physical status I-II, undergoing elective surgery were randomly assigned into 4 groups of 31 each. Group I received normal saline, group II received lidocaine 2% (40 mg), and groups III and IV received thiopental 0.25 mg/kg and 0.5 mg/kg, respectively. All pretreatment drugs were made in 2 mL and were accompanied by manual venous occlusion for 1 min. Propofol was administered after release of venous occlusion. Pain was assessed with a four-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain, and 3 = severe pain at the time of propofol injection. Twenty-four patients (77%) complained of pain in the group pretreated with normal saline as compared with 12 (39%), 10 (32%), and 1 (3%) in the groups pretreated with lidocaine 40 mg, thiopental 0.25 mg/kg, and thiopental 0.5 mg/kg, respectively (P < 0.05). Thiopental 0.5 mg/kg was the most effective treatment. We therefore suggest routine pretreatment with thiopental 0.5 mg/kg along with venous occlusion for 1 min for prevention of pain associated with propofol injection. IMPLICATIONS: Pain associated with IV injection of propofol is seen in 28%-90% patients. Pretreatment with thiopental 0.25 mg/kg and 0.5 mg/kg after manual venous occlusion for 1 min effectively attenuated pain associated with propofol injection. Thiopental 0.5 mg/kg was the most effective in prevention of propofol pain and can be used routinely.     

Vein pretreatment with magnesium sulfate to prevent pain on injection of propofol is not justified

PURPOSE: Propofol produces anesthesia with rapid recovery. However, it causes pain or discomfort on injection. A number of techniques have been tried for minimizing propofol-induced pain with variable results. We have compared the efficacy of magnesium and lidocaine for the prevention of propofol induced pain. METHODS: Three hundred ASA I and II adults undergoing elective surgery were randomly assigned into three groups of 100 each. Group I received magnesium sulfate 1 g, Group II received lidocaine 2% (40 mg) and Group III received normal saline, all in a volume of 2 mL and accompanied by venous occlusion for one minute. Induction with propofol 2.5 mg.kg(-1) was accomplished following the release of venous occlusion. Pain was assessed on a four-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain, and 3 = severe pain at the time of pretreatment and propofol injection. Results were analyzed by 'Z' test. A P value of < 0.05 was considered as significant. RESULTS: Pain during i.v. pretreatment with magnesium was 31% as compared to 2% for both the lidocaine and control groups (P < 0.05). Seventy-six percent of patients in the control group had pain during i.v. propofol as compared to 32% and 42% in the magnesium and the lidocaine groups respectively (P < 0.05). Lidocaine and magnesium pretreatment were equally effective in attenuating pain during the propofol injection (P > 0.05). CONCLUSIONS: Intravenous magnesium and lidocaine pretreatment are equally effective in attenuating propofol-induced pain. However, magnesium pretreatment itself causes pain. Therefore, there is no justification in the use of magnesium pretreatment for attenuating pain associated with i.v. propofol.     

Propofol prevents lipid peroxidation following transient forebrain ischemia in gerbils

PURPOSE: To ascertain whether propofol prevents lipid peroxidation on delayed neuronal death induced by transient forebrain ischemia in the hippocampal CA1 subfield in gerbils. METHODS: Forty gerbils were randomly assigned to five groups: Group I, control, sham operation treated with physiological saline solution (PSS); Group II, ischemia/reperfusion treated with PSS; Group III, ischemia/reperfusion treated with 50 mg x kg(-1) propofol; Group IV, ischemia/reperfusion treated with 100 mg x kg(-1) propofol; Group V, ischemia/reperfusion treated with 150 mg x kg(-1) propofol. Transient forebrain ischemia was induced by occluding the bilateral common carotid arteries for four minutes under N2O/O2/halothane anesthesia after propofol or PSS. Five days later, the cerebrum was removed and each forebrain was cut into two including the hippocampus. Lipid peroxidation was determined using the production of malondialdehyde (MDA), and histopathological changes in the hippocampal CA1 subfield were examined. RESULTS: In group II, the pyramidal cells were atrophic and pycnotic; vacuolation and structural disruption of the radial striated zone was observed. In the other four groups, these changes were not observed. Degenerative ratios of pyramidal cells were: Group I: 4.9 +/- 2.3, Group II: 94.1 +/- 4.5 (P < 0.01), Group III: 12.5 +/- 5.7, Group IV: 11.0 +/- 4.6, Group V: 9.6 +/- 4.9%. Production of MDA was: Group I: 83 +/- 22, Group II: 198 +/- 25 (P < 0.01), Group III: 153 +/- 39, Group IV: 113 +/- 34, Group V: 106 +/- 27 nmol x g(-1) wet tissue. CONCLUSION: Propofol attenuated delayed neuronal death by preventing lipid peroxidation induced by transient forebrain ischemia in the hippocampal CA1 subfield in gerbils.     

Prevention of propofol-induced injection pain by remifentanil: a placebo-controlled comparison with lidocaine

In a randomised, double-blind study we compared the efficacy of continuous remifentanil infusion (0.25 microg x kg(-1) x min(-1) with 40 mg lidocaine and placebo in the prevention of injection pain due to intravenous propofol administration (1.5-2 mg x kg(-1)) in 155 patients scheduled for elective surgery. Pain severity was evaluated using a four-point scale. The incidence of injection pain was 62% in the placebo group and could be reduced significantly by using remifentanil (30%; p < 0.0015) or lidocaine (33%; p < 0.005). Analysis of the pain scores showed a significant difference between remifentanil and placebo (p < 0.00005) as well as between lidocaine and placebo (p < 0.0002). There was no significant difference between remifentanil and lidocaine. Remifentanil provided effective pain relief, comparable with lidocaine, and is an alternative as part of an intravenous anaesthesia regimen to using another concomitant drug.     

Remifentanil versus alfentanil in total intravenous anaesthesia for day case surgery

BACKGROUND AND OBJECTIVE: We assessed the intraoperative haemodynamic responses and recovery profiles of total intravenous anaesthesia with remifentanil and alfentanil for outpatient surgery. METHODS: Patients in Group 1 (n = 20) received alfentanil 20 microg kg(-1) followed by 2 microg kg(-1) min(-1) intravenously; patients in Group 2 (n = 20) received remifentanil 1 microg kg(-1) followed by 0.5 microg kg(-1) min(-1) intravenously. Both groups then received propofol 2 mg kg(-1) followed by 9 mg kg(-1) h(-1) intravenously. Five minutes after skin incision, infusion rates were decreased, and at the end of surgery, all infusions were discontinued. Early recovery was assessed by the Aldrete score, whereas intermediate recovery was assessed with the postanaesthetic discharge scoring system (PADS). RESULTS: Perioperative arterial pressure was similar in both groups; heart rate was lower in Group 2 (P < 0.05). The times to spontaneous and adequate respiration, response to verbal commands, extubation and times for Aldrete score > or = 9 were shorter in Group 2 patients (P < 0.05). Pain scores were higher in Group 2 patients (P < 0.05). Overall times for postanaesthetic discharge scores > or = 9 were similar. CONCLUSIONS: Early recovery of patients after day surgery is significantly shorter after total intravenous anaesthesia with remifentanil compared with that with alfentanil but postoperative pain management must be planned ahead.     

Intravenous lidocaine 0.5 mg·kg-1 effectively suppresses fentanyl-induced cough

PURPOSE: To evaluate the minimal dose of lidocaine required for suppression of fentanyl-induced cough. METHODS: 320 ASA I and II patients, non-smokers of both sexes scheduled for elective surgery between the ages of 18 to 60 yr were randomly allocated into four equal groups. The patients were assigned to receive lidocaine 0.5 mg.kg(-1) (Group I), 1.0 mg.kg(-1)(Group II), 1.5 mg.kg(-1) (Group III) or placebo (Group IV) over five seconds, one minute prior to the administration of fentanyl 3 microg.kg(-1) in a randomized and double-blind fashion. Any episode of cough was classified as coughing and graded as mild (1-2) moderate (3-4) or severe (5 or more). The data were analyzed by test of proportion. RESULTS: Eleven, 12, 11 and 28 patients (13.75%, 15%, 13.75% and 35%) had cough in Groups I, II, III and IV respectively (P < 0.05 Groups I, II, III vs IV). There was no significant difference in the incidence and severity of cough among the lidocaine pretreated groups (P > 0.05). CONCLUSION: The results of our study suggest that iv lidocaine 0.5 mg.kg(-1) is the minimal dose required to suppress fentanyl-induced cough when administered one minute prior to fentanyl. Any further increase in the lidocaine dose does not reduce the incidence or severity of fentanyl-induced cough.     

A novel mixture of propofol, alfentanil, and lidocaine for regional block with monitored anesthesia care in ophthalmic surgery

STUDY OBJECTIVE: The purpose of this study is to determine the efficacy and safety of sedation/analgesia using a mixture of propofol, alfentanil, and lidocaine. DESIGN: A retrospective case review was undertaken. SETTING: This study took place at a university medical center. PATIENTS: Eighty-nine American Society of Anesthesiologists physical status 1, 2, and 3 adult patients undergoing ophthalmic surgery with regional block and monitored anesthesia care were studied. INTERVENTION: Six milliliters of propofol, 2 mL of alfentanil, and 2 mL of 2% lidocaine (6-2-2 mixture) were freshly mixed. The bolus dose was determined based on the patients' age: 5 microg/kg of alfentanil (and 0.3 mg/kg of propofol) for patients older than 75 years; the dose increased 1 mug/kg per 10-year decrease in age; and up to 9 microg/kg of alfentanil (0.54 mg/kg of propofol) for patients younger than 45 years. Regional block was performed at 1 minute after bolus completion. Blood pressure (BP), Sa(O2), electrocardiogram, capnography, clinical signs of sedation, responses to block, need for airway support, nausea and vomiting (N/V), pain due to propofol infusion, recall, and patient and surgeon satisfaction were recorded. MEASUREMENTS AND MAIN RESULTS: Seventy-eight percent of patients achieved analgesia and sedation without adverse response to the block. Twelve percent achieved good analgesia and sedation with only eyebrow movement upon needle insertion. Twenty-seven percent had respiratory depression but were able to follow commands and maintain adequate ventilation. Two percent had brief apnea alleviated by chin lift or jaw thrust. None had pain because of propofol infusion or N/V. Before sedation, average systolic BP was significantly increased (P < 0.0001) compared with baseline. After sedation and block, systolic BP decreased 6% from baseline (P < 0.005). CONCLUSION: Adjusted for age and weight, the dose of the 6-2-2 mixture met the sedation requirements for most patients. With a low incidence of need for airway support, no pain during infusion, and no N/V, this novel mixture of propofol, alfentanil, and lidocaine provided adequate analgesia and sedation as well as hemodynamic stability for ophthalmic surgery under regional block.