Aminophylline reduces the depth and duration of sedation with barbiturates

The effect of preoperative aminophylline on the recovery profile after major pelvic-abdominal surgeries: a randomized controlled double-blinded study

Background

This study compared the effects of premedication with different doses of aminophylline on the recovery profile after general anaesthesia.

Methods

Forty-five patients scheduled for pelvic-abdominal surgeries were divided into 3 groups: Group C: the patients received 100 ml of IV normal saline, Group A1: the patients received 2 mg/kg IV aminophylline, and Group A2: the patients received 4 mg/kg IV aminophylline 30 min before induction of general anaesthesia. The following data were recorded: demographic data, ASA physical status, duration of anaesthesia and surgery, heart rate, mean arterial blood pressure, propofol dose, fentanyl dose, times to reach BIS (48 ± 2) after induction of anaesthesia and to reach a value of 80 after discontinuation of sevoflurane anaesthesia, time to recovery of consciousness and to tracheal extubation and to discharge from the post-anaesthesia care unit, and side effects of aminophylline.

Results

The time to reach a BIS of 48 ± 2 was significantly lower for the control group than group A2 (70.67 ± 22.50 and 106.67 ± 34.77 s for groups C and A2, respectively, p -value =0.01). The time to reach a BIS of 80 was significantly longer for the control group than group A1 andA2 (5.6 ± 1.40,3.5 ± 1.93and 2.53 ± 1.72 min for groups C,A1 and A2, respectively, p -value < 0.01). The time to ROC was significantly longer for the control group than groups A1 and A2 (8.93 ± 0.92, 5.6 ± 2.47 and 4.53 ± 3.33 min for groups C, A1 and A2, respectively; p -value < 0.01). The extubation time was significantly longer for the control group than groups A1 and A2 (12.4 ± 1.08, 7.87 ± 3.27 and 6.6 ± 2.47 min for groups C, A1 and A2, respectively; p -value < 0.01).

Conclusion

Premedication with aminophylline enhanced the recovery profile after pelvic-abdominal surgeries under general anaesthesia without cardiovascular complications.

Clinical trial registration

Name of the registry: Register@ClinicalTrials.gov

Trial registration number: ClinicalTrials.gov Identifier: NCT04151381.

Date of registration, November 5, 2019, ‘Retrospectively registered’.

Aminophylline and Ephedrine, but Not Flumazenil, Inhibit the Activity of the Excitatory Amino Acid Transporter 3 Expressed in Xenopus Oocytes and Reverse the Increased Activity by Propofol

We investigated the effects of flumazenil, aminophylline, and ephedrine on the excitatory amino acid transporter type 3 (EAAT3) activity and the interaction with propofol. EAAT3 was expressed in the Xenopus oocytes. L-Glutamate-induced membrane currents were measured using the two-electrode voltage clamp at various drug concentrations. Oocytes were preincubated with protein kinase C- (PKC-) activator, or inhibitor, and phosphatidylinositol 3-kinase (PI3K) inhibitor. To study the interaction with propofol, oocytes were exposed to propofol, propofol + aminophylline, or ephedrine. Aminophylline and ephedrine significantly decreased EAAT3 activity. Aminophylline (95 μM) and ephedrine (1.19 μM) significantly decreased Vmax, but not Km of EAAT3, for glutamate. The phorbol 12-myristate-13-acetate-induced increase in EAAT3 activity was abolished by aminophylline or ephedrine. The decreased EAAT3 activities by PKC inhibitors (staurosporine, chelerythrine) and PI3K inhibitor (wortmannin) were not significantly different from those by aminophylline or ephedrine, as well as those by PKC inhibitors or PI3K inhibitor + aminophylline or ephedrine. The enhanced EAAT3 activities induced by propofol were significantly abolished by aminophylline or ephedrine. Aminophylline and ephedrine inhibit EAAT3 activity via PKC and PI3K pathways and abolish the increased EAAT3 activity by propofol. Our results indicate a novel site of action for aminophylline and ephedrine.

The effects of intravenous aminophylline on level of consciousness in acute intentional benzodiazepines poisoning in comparison to flumazenil

AIM

Acute intentional benzodiazepine poisoning is marked by a significant loss of consciousness, aspiration pneumonia, and increased rates of mortality and morbidity, especially in older patients with underlying heart or lung disease. These patients may need flumazenil to reverse the respiratory effects of benzodiazepines. The positive effects of aminophylline on respiration and neonatal apnea improvement have been shown previously. However, its possible effects on increasing the level of consciousness have never been evaluated.

METHODS

In a placebo-controlled study, we assessed the effectiveness of aminophylline on increasing the level of consciousness.

RESULTS

Time to full awakening was significantly shorter in those who received aminophylline (72 min vs. 881 min, p = 0.001), compared to those who received a placebo.

CONCLUSION

When "flumazenil" is contraindicated or unavailable, intravenous aminophylline can be used as a second choice.

The effects of Aminophylline on clinical recovery and bispectral index in patients anesthetized with total intravenous anaesthesia

OBJECTIVE

Aminophylline, which is clinically used as a bronchodilator, antagonizes the action of adenosine, so it can be used to shorten the recovery time after general anesthesia. Therefore, we wanted to test the hypothesis that the administration of aminophylline leads to an increase in bispectral index (BIS) and clinical recovery in patients anesthetized with total intravenous anesthesia (TIVA). Methods : Ninety two patients who were scheduled for elective inguinal herniorrhaphy were enrolled in this study. All patients were premedicated with midazolam and morphine. Anesthesia was induced with propofol 2.5 mg /kg and remifentanil 2.5 µg/kg without muscle relaxant. For maintenance of anesthesia we used propofol 100µg/kg/min, remifentanil 0.2µg/kg/min and 100% oxygen with stable BIS readings in the range 40-60. After skin closure, aminophylline 4mg/ kg was given to Group A and an equivalent volume of normal saline to Group P. BIS values, heart rate, blood pressure, oxygen saturation and End tidal CO2(ETco2) were determined. Time to eye opening, extubation time and response to command were measured. Results : There were no significant differences in SpO2, ETco2 and anesthesia time. Heart rate and systolic blood pressure were found to be statistically higher (p<0.001) in Group A. Time to eye opening, hand grip and extubation were significantly shorter (p<0.001) in Group A. Bispectral index scores were significantly higher in group A.

CONCLUSIONS

Injection of aminophylline at emergence time led to significant increase in BIS and shortening recovery time from anesthesia.

Impact of aminophylline on the pharmacodynamics of propofol in beagle dogs

This study aimed to characterize pharmacodynamic interaction between propofol and aminophylline. Nine beagle dogs were randomly allocated at the propofol rates of 0.75 (group A), 1.00 (group B), and 1.25 (group C) mg/kg/min. During period 1, propofol only was infused, while during period 2, aminophylline only, at the rate of 0.69 (group A), 1.37 (group B), and 2.62 (group C) mg/kg/h. During periods 3-5, the two drugs were co-administered. The aminophylline infusion rate was 0.69 (period 3), 1.37 (period 4), and 2.62 (period 5) mg/kg/h. The aminophylline was infused from 0 to 30 h, and the propofol was infused at 24 h for 20 min. Blood samples and electroencephalograms were obtained at preset intervals. In the linear regression between log-transformed doses of aminophylline and AUC inf, the slope was 0.6976 (95% CI 0.5242-0.8710). Pharmacokinetics of aminophylline was best described by a one-compartment, with enzyme auto-induction, model. Pharmacokinetics and pharmacodynamics of propofol were best described by a three-compartment model and a sigmoid Emax model, respectively. Pharmacodynamic parameter estimates of propofol were: k(e0) = 0.805/min, E0 = 0.76, Emax = 0.398, Ce(50 na) = 2.38 μg/mL (without aminophylline-exposure), C(e50 wa) = 4.49 μg/mL (with aminophylline-exposure), and γ = 2.21. Propofol becomes less potent when exposed to aminophylline. Pharmacodynamic antagonistic interaction of aminophylline with propofol sedation, may occur, not in a dose-dependent manner, but in an all-or-none response.

Comparison of the recovery and respiratory effects of aminophylline and doxapram following total intravenous anesthesia with propofol and remifentanil

STUDY OBJECTIVE

To compare the effects of aminophylline and doxapram on recovery, respiration, and bispectral index (BIS) values in patients after total intravenous anesthesia (TIVA) with propofol and remifentanil.

DESIGN

Prospective, randomized, blinded clinical trial.

SETTING

Operating room of a university hospital.

PATIENTS

90 adult, ASA physical status 1 and 2 patients scheduled for elective laparoscopic vaginal hysterectomy.

INTERVENTIONS

TIVA was performed with the induction target of remifentanil 3 ng/mL and propofol 6 μg/mL, followed by the maintenance target of remifentanil 1-3 ng/mL and propofol 3-5 μg/mL at the effect site, and with BIS scores in 40-50 range. Patients were randomized to three groups to receive intravenous (IV) aminophylline 3 mg/kg (n = 30), IV doxapram 1 mg/kg (n = 30), or normal IV saline (control; n = 30).

MEASUREMENTS AND MAIN RESULTS

After administration of the study drugs, return to spontaneous ventilation differed significantly among the three groups. The times to eye opening and hand squeezing on verbal command were similar. The time to extubation was shortened in both the doxapram and aminophylline groups (P < 0.05). Tidal volumes were increased in the doxapram group at 5-14 minutes and the aminophylline group at 5-12 minutes (P < 0.05). Respiratory rates were increased at 2 to 8 minutes and then showed a decrease at the 12 to 14-minute mark in both the doxapram and aminophylline groups (P < 0.05). No difference was noted between the two groups. BIS values were increased in both the doxapram and aminophylline groups at 4-10 minutes (P < 0.05). Heart rates were increased in the doxapram group for the first 8 minutes and at 1-2 minutes in the aminophylline group (P < 0.05).

CONCLUSION

Aminophylline 3 mg/kg or doxapram 1 mg/kg shortened the time to spontaneous ventilation and improved early recovery from TIVA without appreciable side effects. The more rapid emergence correlates with higher BIS values when compared with the saline control group. The arousal and respiratory effects of aminophylline were comparable to those of doxapram.

Effects of aminophylline on cognitive recovery after sevoflurane anesthesia

PURPOSE

Aminophylline accelerates the recovery from sevoflurane anesthesia. We studied the effects of escalating doses of aminophylline on cognitive and clinical recovery after sevoflurane anesthesia.

METHODS

After ethical approval and informed consent, 150 patients scheduled for elective surgery under sevoflurane-fentanyl anesthesia were randomly allocated to receive saline or 2, 3, 4 or 5 mg/kg of aminophylline (n = 30 for each) at the end of anesthesia (T (0)). Short Orientation Memory Concentration Test (SOMCT) scores, entropy values, end-tidal sevoflurane concentrations (EtSevo), times to eyes opening and extubation, respiratory rate (RR) and tidal volume (TV) were recorded.

RESULTS

Compared to placebo, patients receiving 2, 3, 4 and 5 mg/kg of aminophylline had higher SOMCT scores [median (25th percentile/75th percentile) 20.6 (19/23), 21.5 (21/22), 24.5 (24-25), 25.5 (25/26), respectively, vs. 13.5 (13/14) at 30 min after extubation, and 24 (22/26), 25 (24/26), 27.5 (27-28), 27.5 (27/28), respectively, vs. 18.5 (18/19) at 45 min after extubation], higher entropy values for the first 10 min after T (0), lower EtSevo for the first 4 min after T (0), shorter times to eyes opening [5 (4.0/6.0), 5 (4.0/6.0), 4 (2.0/5.5), and 4 (2.0/6.0), respectively, vs. 9.8 (8.0/11.0) min], shorter times to extubation, shorter times to home discharge (P < 0.001), and higher RR and larger TV values. Patients who received 4 and 5 mg/kg of aminophylline showed higher SOMCT scores, 6 min shorter times to eyes opening and to extubation, and 58 min shorter times to home discharge.

CONCLUSION

The administration of escalating doses of aminophylline accelerates postoperative cognitive recovery from sevoflurane anesthesia, as measured by the SOMCT, due to increased ventilatory elimination of sevoflurane.

The effect of aminophylline on loss of consciousness, bispectral index, propofol requirement, and minimum alveolar concentration of desflurane in volunteers

BACKGROUND

Adenosine is a soporific neuromodulator; aminophylline, which is clinically used as a bronchodilator, antagonizes the action of adenosine in the central nervous system. Thus, we tested the hypothesis that aminophylline delays loss of consciousness (LOC) and speeds recovery of consciousness (ROC) with propofol anesthesia, and that aminophylline increases the minimum alveolar concentration (MAC) of desflurane.

METHODS

In this double-blind crossover study, volunteers were randomized to either aminophylline or saline on different days. Aminophylline 6 mg/kg was given IV, followed by 1.5 mg x kg(-1) x h(-1) throughout the study day. After 1 h of aminophylline or saline administration, propofol 200 mg was given at a rate of 20 mg/min. The bispectral index was continuously monitored, as were times to LOC and ROC. After recovery from propofol, general anesthesia was induced with sevoflurane and subsequently maintained with desflurane. The Dixon "up-and-down" method was used to determine MAC in each volunteer after repeated tetanic electrical stimulation.

RESULTS

Eight volunteers completed both study days. Time to LOC was prolonged by aminophylline compared with saline (mean +/- SD) (7.7 +/- 2.03 min vs 5.1 +/- 0.75 s, respectively, P = 0.011). The total propofol dose at LOC was larger with aminophylline (2.2 +/- 0.9 vs 1.4 +/- 0.4 mg/kg, P = 0.01), and the time to ROC was shorter (6.18 +/- 3.96 vs 12.2 +/- 4.73 min, P = 0.035). The minimum bispectral index was greater with aminophylline (51 +/- 15 vs 38 +/- 9, P = 0.034). There was no difference in MAC.

CONCLUSION

Aminophylline decreases the sedative effects of propofol but does not affect MAC of desflurane as determined by tetanic electrical stimulation.

Aminophylline reversal of prolonged postoperative sedation induced by propofol

Propofol is frequently used for intravenous sedation or anesthesia in ambulatory and office-based anesthesia. Although awakening is usually rapid, there are instances of delayed recovery from propofol anesthesia. It has been reported that aminophylline antagonizes the sedative effects of several anesthetic and analgesic drugs. The case reports presented here demonstrate that intravenous aminophylline effectively reversed prolonged propofol-induced sedation/anesthesia in the postoperative period. There were no side effects or delayed re-sedation after the administration of aminophylline. Our study suggests that aminophylline could be a clinically useful propofol antagonist.

The effects of aminophylline on bispectral index during inhalational and total intravenous anaesthesia

Aminophylline is usually used during anaesthesia to treat bronchospasm but recent findings suggest that it can also be used to shorten recovery time after general anaesthesia. However, it is unclear whether aminophylline shows similar properties during a steady-state phase of deep surgical anaesthesia. We therefore wanted to test the hypothesis that the administration of aminophylline leads to an increase in bispectral index as a surrogate parameter suggesting a lighter plane of anaesthesia. The study was designed as a double-blind, randomised, controlled trial with two main groups (aminophylline and placebo) and two subgroups (sevoflurane and propofol). We studied 60 patients. The injection of aminophylline 3 mg x kg(-1) was associated with significant increases in bispectral index up to 10 min after its injection, while heart rate and blood pressure did not change. It appears that aminophylline has the ability to partially antagonise the sedative effects of general anaesthetics.

Doxapram and aminophylline on bispectral index under sevoflurane anaesthesia

BACKGROUND AND OBJECTIVE

To evaluate and compare the effect of two clinically available central nervous system stimulants, namely doxapram and aminophylline on arousal from sevoflurane anaesthesia and bispectral index.

METHODS

This randomized, double-blind, placebo-controlled, prospective study was conducted in 90 adult females, ASA I-II, scheduled for elective lower abdominal surgeries at Taipei Medical University Hospital. At 5 min before the completion of surgery, under sevoflurane anaesthesia, patients were divided into three groups to receive doxapram 1 mg kg(-1), aminophylline 2 mg kg(-1) or saline placebo intravenous. Standard vital signs, end-tidal CO(2), end-expiratory sevoflurane concentration, bispectral index and neuromuscular blockade were measured plus clinical parameters of recovery from general anaesthesia.

RESULTS

Compared with the control group, patients receiving doxapram or aminophylline showed a similarly faster recovery from sevoflurane anaesthesia correlated with increase in bispectral index.

CONCLUSION

Intravenous administration of doxapram 1 mg kg(-1) or aminophylline 2 mg kg(-1) hastened the early recovery from sevoflurane anaesthesia. The arousal effect of aminophylline and doxapram appears to be similar.

Effect of aminophylline on bispectral index

BACKGROUND

The aim of the present study was to investigate the effects of aminophylline on BIS as well as clinical recovery in patients anesthetized with sevoflurane.

METHODS

Sixty patients with status of ASA I-II scheduled for elective surgery were enrolled in this study. Anesthesia was induced by 2 mg kg(-1) of propofol and 0.5 mg kg(-1) of atracurium, maintained with 1:1 ratio of oxygen and nitrous oxide and 2-2.5% sevoflurane, keeping BIS values at 50 +/- 5. During the last 30 min of the operation no muscle relaxant was given and anesthesia was continued without decreasing anesthetic concentration. After sevoflurane discontinuation, saline was given to Group P, and 5 mg kg(-1) of aminophylline was given to Group A. Bispectral index values, heart rate, blood pressure and oxygen saturation were determined in all the patients before and every min after injection of the test drug for 15 min. The following variables were measured in both groups: eye opening, extubation time, response to command, Aldrete scores, and performing three simple arithmetic calculations.

RESULTS

Between groups there was no statistically significant difference in mean arterial blood pressure, SpO2 and anesthesia time. Heart rate was found to be statistically higher (P < 0.001) at 2 to 6 min in Group A when compared with group P. Eye opening, verbal response, extubation and arithmetic calculation times were significantly shorter (P < 0.001) in Group A. Bispectral index scores were significantly higher in Group A at 1 to 12 min after aminophylline injection when compared with placebo (P < 0.001).

CONCLUSION

Recovery from sevoflurane anesthesia and BIS scores are improved in early period when aminophylline is given at emerging from anesthesia.

Recovery after total intravenous anaesthesia using combined midazolam/alfentanil infusion and reversal with flumazenil

One of the major problems with total intravenous anaesthesia (TIVA) is postoperative sedation, possibly with respiratory depression. The aim of the present study was to evaluate the recovery characteristics after TIVA using a continuous infusion of a mixture of midazolam and alfentanil with flumazenil reversal before extubation. This method was compared to balanced anaesthesia using midazolam, alfentanil and nitrous oxide without flumazenil reversal. The degree of sedation was measured by reaction time test, Glasgow Coma Scale, cipher copying test and subtraction test. We found significantly faster reaction times postoperatively in the TIVA group (n = 15) compared to the balanced group (n = 13), despite larger doses of both midazolam (median 21 mg versus 9 mg) and alfentanil (median 5.9 mg versus 4.5 mg). The other tests revealed no difference between the groups. One patient became resedated after flumazenil. We conclude that the TIVA technique described here resulted in slightly better recovery characteristics, offering a usable alternative to balanced anaesthesia.

Effect of aminophylline or physostigmine on recovery from nitrous oxide-enflurane anaesthesia

If facilities for recovery are limited, shortening the recovery time from general anaesthesia is important. A comparative study on the effect of 3 mg.kg-1 aminophylline or 0.04 mg.kg-1 physostigmine on duration and quality of the recovery time from nitrous oxide-enflurane anaesthesia is presented. Three groups of 35 patients were observed, placebo being included for comparison in this double-blind study. Without treatment, recovery from nitrous oxide-enflurane inhalation anaesthesia lasted 18.8 +/- 5.80 min. Aminophylline considerably shortened the recovery time (12.06 +/- 3.52 min), whereas physostigmine did not (18.97 +/- 9.18 min). In the physostigmine group, however, a remarkably calm recovery and early return of protective reflexes was observed. Although aminophylline shortens the recovery time, due to earlier incidence of pain and other disturbances, it cannot be recommended for general improvement of recovery, whereas physostigmine clearly improves the quality of recovery from nitrous oxide-enflurane anaesthesia.

Comparison of induction with and first hour of recovery from brief propofol and methohexital anesthesia

Anesthesia and recovery during the first hour after propofol and methohexital anesthesia for termination of pregnancy, lasting about 12 min, were compared, the latter in a double-blind manner by means of psychomotor tests (coin counting and continuous auditory reaction time). Muscle movements and hiccups were seen significantly more frequently during methohexital inductions. No differences were seen regarding pain at the site of injection or apnea between the groups. At 15 min after the last dose of anesthetic, recovery after methohexital was ahead of that after propofol, but after 1 h, psychomotor performance was better in the propofol group. Side-effects during recovery were few, and incidences did not differ significantly. Although the difference in reaction time test was significant, it was hardly large enough to be of any clinical importance. Both drugs are useful for brief outpatient anesthesia, but smoother induction gives propofol an edge over methohexital.

Induction and recovery characteristics of propofol, thiopental and etomidate

Propofol, thiopental and etomidate, with 20 patients in each group, were compared for anesthesia of short duration in women undergoing termination of pregnancy, with respect to: 1: pain on injection (equally often after propofol and etomidate, but more rarely after thiopental); 2: apnea following induction (no difference); 3: involuntary muscular movements more frequent after etomidate); 4: blood pressure (larger drop after propofol); 5: heart rate (greater increase after thiopental); 6: time to eye opening on command (longer after propofol); 7: Steward score on eye opening (no difference); 8: coin counting after 15, 30 and 60 min (performance better after propofol at 15 and 30 min, producing even shorter times than preoperatively at 60 min); 9: reaction time after 15, 30 and 60 min (performance better after propofol, producing even shorter times than preoperatively at 60 min. It is concluded that the faster recovery gives propofol an advantage over thiopental and etomidate in outpatient anesthesia.