Aminophylline reversal of prolonged postoperative sedation induced by propofol

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.

Delayed recovery from anesthesia: A postgraduate educational review

Delayed awakening from anesthesia remains one of the biggest challenges that involve an anesthesiologist. With the general use of fast-acting anesthetic agents, patients usually awaken quickly in the postoperative period. The time to emerge from anesthesia is affected by patient factors, anesthetic factors, duration of surgery, and painful stimulation. The principal factors responsible for delayed awakening following anesthesia are anesthetic agents and medications used in the perioperative period. Nonpharmacological causes may have a serious sequel, hence recognizing these organic conditions is important. Certain underlying metabolic disorders such as hypoglycemia, severe hyperglycemia, and electrolyte imbalance, especially hypernatremia, hypoxia, hypercapnia, central anticholinergic syndrome, chronic hypertension, liver disease, hypoalbuminemia, uremia, and severe hypothyroidism may also be responsible for delayed recovery following anesthesia. Unexpected delayed emergence after general anesthesia may also be due to intraoperative cerebral hypoxia, hemorrhage, embolism, or thrombosis. Accurate diagnosis of the underlying cause is the key for the institution of appropriate therapy, but primary management is to maintain airway, breathing, and circulation. This comprehensive review discusses the risk factors, causes, evaluation and management of delayed recovery based on our clinical experience, and literature search on the internet, supported by the standard textbooks of anesthesiology.

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.

Antidepressant effect of aminophylline after ethanol exposure

This work investigated the association of acute ethanol and aminophylline administration on behavioral models of depression and prefrontal monoamine levels (i.e. norepinephrine and dopamine) in mice. The animals received a single dose of ethanol (2 g/kg) or aminophylline (5 or 10 mg/kg) alone or in association. Thirty minutes after the last drug administration, the animals were assessed in behavioral models by the forced swimming and tail suspension tests. After these tests, the animals were sacrificed and the prefrontal cortices dissected to measure monoamine content. Results showed that ethanol presented depression-like activity in the forced swimming and tail suspension tests. These effects were reversed by the association with aminophylline in all tests. Norepinephrine and dopamine levels decreased, while an increase in the dopamine metabolite, (4-hydroxy-3-methoxyphenyl)acetic acid (DOPAC), after ethanol administration was observed. On the contrary, the association of ethanol and aminophylline increased the norepinephrine and dopamine content, while it decreased DOPAC when compared to the ethanol group, confirming the alterations observed in the behavioral tests. These data reinforce the involvement of the adenosinergic system on ethanol effects, highlighting the importance of the norepinephrine and dopamine pathways in the prefrontal cortex to the effects of ethanol.

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.

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.