Cotinine Overcome the Decrease of Prostacyclin Formation Induced by Nicotine after Sympathetic Stimulation in Microsomes from Isolated Rabbit Heart.

We studied the effects of cotinine, the major metabolite of nicotine, on nicotine-induced decrease in prostacyclin (PGI2) synthase activity of microsomes from isolated rabbit heart after sympathetic stimulation. Rabbit hearts were isolated along with their sympathetic nerves and perfused in accordance to the Langendorff method. Hearts were randomly divided into 10 groups treated with cotinine, either during sympathetic stimulation or prior to nicotine administration. PGI2 formation in cardiac microsomes was assessed by radioimmunoassay. The results showed that sympathetic stimulation increased PGI2 synthase activity of heart microsomes by 32 %. Nicotine dose dependently decreased PGI2 while cotinine increased it. In addition, perfused before nicotine, cotinine prevented the PGI2 decreasing effect of nicotine. The results suggest that pre-treatment with cotinine can be involved in the modulation of nicotine effects on PGI2 in hearts subjected to sympathetic stimulation.

The Effects of a Combination of Nicardipine and Esmolol on Blood Pressure and Heart Rate after Endotracheal Intubation in Hypertensive Patients / 대한마취과학회지

BACKGROUND: This study was designed to determine the efficacy of a combined use of esmolol and nicardipine for blunting hypertension and tachycardia after tracheal intubation in hypertensive patients. METHODS: Forty-five hypertensive patients were randomly divided into three group: group E (esmolol 0.5 mg/kg, n = 15), group N (nicardipine 30microgram/kg, n = 15), group EN (esmolol 0.25 mg/kg, nicardipine 15microgram/kg, n = 15). All patients received midazolam 0.5 mg/kg, and glycopyrrolate 0.2 mg IM for premedication. Fentanyl 1microgram/kg was injected before induction of anesthesia, and then esmolol, nicardipine, or the mixed drugs were administrated as an IV bolus and immediately followed by the induction drugs: thiopental 5 mg/kg, and succinylcholine 1 mg/kg. Endotracheal intubation was performed 90 seconds after injection of the experimental drugs. Thereafter 50% Nitrous Oxide in oxygen and 2 vol % enflurane were inhaled. BP and HR were recorded at the resting state, before fentanyl injection (base {T0}), after injection test drug (T1), after induction (T2), immediately after intubation (T3), 2 min (T4), 3 min (T5), 4 min (T6), and 5 min (T7) after intubation. RESULTS: There was a significant attenuation in SBP, MBP, DBP after tracheal intubation on the nicardipine and mixed groups compared to the esmolol group. HR was significantly lower in the esmolol and mixed groups than in the nicardipine group after tracheal intubation. CONCLUSIONS: Combined administration of esmolol (0.25 mg/kg) and nicardipine (15microgram/kg) was effective in attenuating an increase of BP and HR during tracheal intubation in hypertensive patients.

QT and RR interval variability and spectral characteristics in response to physiologic autonomic stimulation

Purpose: The purposes of this study were to compare the magnitude and phase between the RR interval and QT interval variability in the frequency domain. METHODS: Twenty four, 12-13 year old healthy males were randomly selected. At resting state and for 5 minutes, ECGs were obtained, and they were digitized to 1000Hz. After measurement of RR interval, QT interval variability was measured using template matching strategy. After normalization of the RR and QT interval time series, power spectral and cross spectral analysis were performed. From each of the time series, low- (0.04-0.15 hertz) and high- (0.15-0.4 hertz) frequency power were measured. From the phase spectrum, the phases and time lags between the two time series at each of the two frequency range were calculated. RESULTS: The average of RR interval and QT interval was 616.0+/-71.0, 364.0+/-47.0 msec, respectively. Their normalized low- and high- frequency power was 4.4+/-7.9 NU(normalized unit), 0.1+/-0.1 NU(p<0.005), and 11.0+/-30.0 NU, 0.3+/-0.3(NU, p<0.005), respectively. The phase differences and resulting time lags between the two interval were -0.5+/-0.4 pi radian(-0.9 seconds) and -0.2+/-0.3 pi radian(-0.4 seconds) in the low- and high-frequency range, respectively. CONCLUSION: During resting state, when compared to RR interval, QT interval oscillates in significantly lower amplitude in both low- and high- frequency ranges. However, the oscillations precede those of the RR interval 0.9 seconds and 0.4 seconds, respectively.

Effects of Verapamil Combined with Esmolol on Blood Pressure and Heart Rates during Tracheal Intubation / 대한마취과학회지

BACKGROUND: Antihypertensive agents such as verapamil and esmolol are well known for their effects of hemodynamic stabilization on tracheal intubation. However, our previous study, Verapamil and esmolol did not attenuate heart rate and blood pressure. The aim of the present study was to evaluate the efficacy of combined administration of these drugs for controlling hemodynamic responses to tracheal intubation. METHODS: Forty-eight patients, ASA physical status I or II, were randomly assigned to one of four groups (n = 12 each):normal saline (control), verapamil 0.1 mg/kg, esmolol 1 mg/kg, and verapamil 0.05 mg/kg mixed with esmolol 0.5 mg/kg. Anesthesia was induced with thiopental 5 mg/kg intravenously, and then saline, verapamil, esmolol or the mixed drugs were administered as an intravenous bolus, and immediately followed by succinylcholine 1.5 mg/kg. Tracheal intubation was performed 90 s after intravenous injection of experimental drugs. Systolic and diastolic blood pressure and heart rate were measured before induction and every minute for 5 minutes after tracheal intubation. RESULTS: There was a significant attenuation in systolic blood pressure after tracheal intubation in the verapamil and mixed groups compared to the control and esmolol groups. Heart rates were significantly lower in the esmolol and mixed groups than in the verapamil groups after tracheal intubation. CONCLUSIONS: Combined administration of Verapamil 0.05 mg/kg with esmolol 0.5 mg/kg attenuated increases in blood pressure and heart rate after tracheal intubation.

A Small Dose of Fentanyl Used Prior to 3 Minutes before Intubation Can Reduce the Incidence of Hypertension and Tachycardia / 대한마취과학회지

BACKGROUND: Tracheal intubation can cause sympathetic stimulation such as hypertension and tachycardia. Many drug are used for reducing the incidence of hypertension and tachycardia induced by intubation. Among these drugs, fentanyl can be used with good result. The purpose of this study was to find the appropriate fentanyl injection time before intubation when a small dose (3 microgram/kg) was used. METHODS: We studied 82 ASA class 1 2 patients, scheduled for gynecological elective surgery, randomized into 5 groups. Group 1 received no fentanyl before intubation, and groups 2, 3, 4 and 5 received 3 microgram/kg fentanyl at 7 min, 5 min, 3 min and 1 min before intubation, respectively. The blood pressure and heart rate were checked at preinduction and post-intubation periods for 5 minutes. RESULTS: The increase of the heart rate was significantly lower in groups 2 and 3 than in group 5 just after intubation. Furthermore the increase of the mean blood pressure was significantly lower in groups 2, 3 and 4 than in group 5 just after intubation. The incidence of tachycardia and hypertension was significantly lower in groups 2, 3 and 4 than in group 5 just after intubation. CONCLUSIONS: When a small dose of fentanyl was used to blunt the intubation induced sympathetic stimulation, the appropriate time was prior to 3 minutes before intubation.

Comparison of Verapamil and Esmolol for Controlling the Blood Pressure and Heart Rate to Tracheal Intubtion / 대한마취과학회지

BACKGROUND: The antihypertensive agents such as verapamil and esmolol are well known about effects of hemodynamic stabilization to tracheal intubation. The aim of the present study was to compare and evaluate the efficacy of those for controlling hemodynamic responses to tracheal intubation. METHODS: Thirty six patients, ASA physical status I or II, were randomly assigned to one of three groups (n=12 each): saline (control), verapamil 0.1 mg/kg and esmolol 1 mg/kg. Anesthesia was induced with thiopental 5 mg/kg intravenously, and then saline, verapamil and esmolol were administered as an intravenous bolus, and immediately followed by succinylcholine 1.5 mg/kg. Tracheal intubation was done 60 s and 90 s after intravenous injection of verapamil and esmolol, respectively. Systolic and diastolic blood pressure and heart rate were measured before induction and every min for 5 minutes after tracheal intubation. RESULTS: There was a significant attenuation in systolic and diastolic arterial pressure after tracheal intubation in verapamil group compared to control group. Heart rate was significantly lower in esmolol group than in verapamil group after tracheal intubation. CONCLUSIONS: Verapamil 0.1 mg/kg and esmolol 1 mg/kg attenuated the increases in blood pressure and heart rate after tracheal intubation, respectively.

Comparison of Verapamil and Esmolol for Controlling the Blood Pressure and Heart Rate to Tracheal Intubation According to the Different Anesthetic Induction Agents / 대한마취과학회지

BACKGROUND: Antihypertensive agents such as verapamil and esmolol are well known for their effects of hemodynamic stabilization on tracheal intubation. But hemodynamic discrepancies in these agents may result from different techniques of anesthetic induction. The aim of the present study was to compare and evaluate their efficacy in controlling hemodynamic responses to tracheal intubation under the different anesthetic induction agents. METHODS: Seventy-two patients, ASA physical status I or II, were randomly assigned to one of six groups (n = 12 each): a Thiopental-Saline (T-S) group and a Propofol-Saline (P-S) group in saline 10 ml; a Thiopental-Verapamil (T-V) group and a Propofol-Verapamil (P-V) group in verapamil 0.1 mg/kg; a Thiopental-Esmolol (T-E) group and a Propofol-Esmolol (P-E) group in esmolol 1 mg/kg according to the induction agents, thiopental or propofol. Anesthesia was induced with thiopental 5 mg/kg or propofol 2 mg/kg intravenous, respectively. Next, saline, verapamil and esmolol were administered as a bolus, and were immediately followed by succinylcholine 1.5 mg/kg. Tracheal intubation was carried out 60 s and 90 s after the intravenous injections of verapamil and esmolol, respectively. Systolic and diastolic blood pressure and heart rate were measured before induction and every minute for 5 minutes after tracheal intubation. RESULTS: There was a significant attenuation in systolic and diastolic arterial pressure after tracheal intubation in the verapamil groups compared to the esmolol groups. Heart rates were significantly lower in the esmolol groups than in the verapamil groups after tracheal intubation. CONCLUSIONS: Verapamil 0.1 mg/kg and esmolol 1 mg/kg attenuated increases in blood pressure and heart rate after tracheal intubation. The different anesthetic induction agents did not influence the hemodynamic effects of verapamil and esmolol on tracheal intubation.

Comparison of Verapamil and Esmolol for Controlling the Blood Pressure and Heart Rate to Tracheal Intubation According to the Different Anesthetic Induction Agents / 대한마취과학회지

BACKGROUND: Antihypertensive agents such as verapamil and esmolol are well known for their effects of hemodynamic stabilization on tracheal intubation. But hemodynamic discrepancies in these agents may result from different techniques of anesthetic induction. The aim of the present study was to compare and evaluate their efficacy in controlling hemodynamic responses to tracheal intubation under the different anesthetic induction agents. METHODS: Seventy-two patients, ASA physical status I or II, were randomly assigned to one of six groups (n = 12 each): a Thiopental-Saline (T-S) group and a Propofol-Saline (P-S) group in saline 10 ml; a Thiopental-Verapamil (T-V) group and a Propofol-Verapamil (P-V) group in verapamil 0.1 mg/kg; a Thiopental-Esmolol (T-E) group and a Propofol-Esmolol (P-E) group in esmolol 1 mg/kg according to the induction agents, thiopental or propofol. Anesthesia was induced with thiopental 5 mg/kg or propofol 2 mg/kg intravenous, respectively. Next, saline, verapamil and esmolol were administered as a bolus, and were immediately followed by succinylcholine 1.5 mg/kg. Tracheal intubation was carried out 60 s and 90 s after the intravenous injections of verapamil and esmolol, respectively. Systolic and diastolic blood pressure and heart rate were measured before induction and every minute for 5 minutes after tracheal intubation. RESULTS: There was a significant attenuation in systolic and diastolic arterial pressure after tracheal intubation in the verapamil groups compared to the esmolol groups. Heart rates were significantly lower in the esmolol groups than in the verapamil groups after tracheal intubation. CONCLUSIONS: Verapamil 0.1 mg/kg and esmolol 1 mg/kg attenuated increases in blood pressure and heart rate after tracheal intubation. The different anesthetic induction agents did not influence the hemodynamic effects of verapamil and esmolol on tracheal intubation.

A Comparison of Fentanyl, Lidocaine and Esmolol for Blunting the Hemodynamic Response during Rapid-Sequence Induction in the Hemodynamically Unstable Patients / 대한마취과학회지

BACKGROUND: Tracheal intubation is accompanied by varing degrees of sympathetic stimulation as reflected by increases in heart rate, and blood pressure and several clinical trials to reduce the effects on blood pressure and heart rate by pharmacologic agents such as and blockers, calcicum channel blockers, narcotics and lidocaine, have been reported. METHODS: To evaluate the effect of fentanyl, lidocaine, esmolol on the hemodynamic changes induced by intubation, we administered thiopental 5 mg/kg only (group 1, n=12), fentanyl 2 g/kg with thiopental 5 mg/kg (group 2, n=12), lidocaine 1 mg/kg with thiopental 5 mg/kg group 3, n=12) or esmolol 0.5 mg/kg with thiopental 5 mg/kg (group 4, n=12) for induction of anesthesia, and measured heart rate, systolic blood pressure, diastolic blood pressure, mean arteiral pressure, and rate-pressure products (RPP) before induction, after induction, after intubation and at 1, 2, 3, and 5 minutes after intubation. RESULTS: There was a significant increase in heart rate, systolic blood pressure and RPP after intubation and 1 min after intubation in all groups, but in group 2, group 3 and group 4, the cardiovascular responses were more attenuated compared to group 1. CONCLUSION: The preintubation intravenous injection of fentanyl, lidocaine and esmolol may offer important roles in the hemodynamically unstable patients because it attenuate cardiovascular responses with intubation.