Comparison of nicardipine, diltiazem and verapamil for controlling the cardiovascular responses to tracheal intubation

Dexmedetomidine as an anesthetic adjunct is associated with reduced complications and cardiac intensive care unit length of stay after heart valve surgery

BACKGROUND

We sought to explore the relationship between dexmedetomidine as an anesthetic adjuvant in cardiac surgery and postoperative complications and length of stay (LOS) in the cardiac intensive care unit (CICU).

METHODS

We conducted a retrospective study of patients aged 18 years and older who underwent heart valve surgery between October 2020 and June 2022. The primary endpoint of the study was major postoperative complications (cardiac arrest, atrial fibrillation, myocardial injury/infarction, heart failure) and the secondary endpoint was prolonged CICU LOS (defined as LOS > 90th percentile). Multivariate logistic regression analysis was performed for variables that were significant in the univariate analysis.

RESULTS

A total of 856 patients entered our study. The 283 patients who experienced the primary and secondary endpoints were included in the adverse outcomes group, and the remaining 573 were included in the prognostic control group. Multivariate logistic regression analysis revealed that age > 60 years (odds ratio [OR], 1.68; 95% confidence interval [CI], 1.23-2.31; p < 0.01), cardiopulmonary bypass (CPB) > 180 min (OR, 1.62; 95% CI, 1.03-2.55; p = 0.04) and postoperative mechanical ventilation time > 10 h (OR, 1.84; 95% CI, 1.35-2.52; p < 0.01) were independent risk factors for major postoperative complications; Age > 60 years (OR, 3.20; 95% CI, 1.65-6.20; p < 0.01), preoperative NYHA class 4 (OR, 4.03; 95% CI, 1.74-9.33; p < 0.01), diabetes mellitus (OR, 2.57; 95% CI, 1.22-5.41; p = 0.01), Intraoperative red blood cell (RBC) transfusion > 650 ml (OR, 2.04; 95% CI, 1.13-3.66; p = 0.02), Intraoperative bleeding > 1200 ml (OR, 2.69; 95% CI, 1.42-5.12; p < 0.01) were independent risk factors for prolonged CICU length of stay. Intraoperative use of dexmedetomidine as an anesthetic adjunct was a protective factor for major complications (odds ratio, 0.51; 95% confidence interval, 0.35-0.74; p < 0.01) and prolonged CICU stay. (odds ratio, 0.37; 95% confidence interval, 0.19-0.73; p < 0.01).

CONCLUSIONS

In patients undergoing heart valve surgery, age, duration of cardiopulmonary bypass, and duration of mechanical ventilation are associated with major postoperative complication. Age, preoperative NYHA classification 4, diabetes mellitus, intraoperative bleeding, and RBC transfusion are associated with increased CICU length of stay. Intraoperative use of dexmedetomidine may improve such clinical outcomes.

Risk factors for acute postoperative hypertension in non-cardiac major surgery: a case control study

PURPOSE

Acute postoperative hypertension (APH) is a common complication during the anesthesia recovery period that can lead to adverse outcomes, including cardiovascular and cerebrovascular accidents. Identification of risk factors for APH will allow for preoperative optimization and appropriate perioperative management. This study aimed to identify risk factors for APH.

PATIENTS AND METHODS

In this retrospective single-center study, 1,178 cases were included. Data was entered by two investigators, and consistency analysis was performed by another. Patients were divided into APH and non-APH groups. A predictive model was built by multivariate stepwise logistic regression. The predictive ability of the logistic regression model was tested by drawing the receiver operating characteristic (ROC) curve and calculating the area under the curve (AUC). Hosmer and Lemeshow goodness-of-fit (GOF) test was performed to reflect the goodness of fit of the model. Calibration curve was created to represent the relationship between predicted risk and observed frequency. Sensitivity analysis was performed to evaluate the robustness of the results.

RESULTS

Multivariate logistic regression analysis showed that age over 65 years (OR = 3.07, 95% CI: 2.14 ~ 4.42, P < 0.001), female patients (OR = 1.37, 95% CI: 1.02 ~ 1.84, P = 0.034), presence of intraoperative hypertension (OR = 2.15, 95% CI: 1.57 ~ 2.95, P < 0.001), and use of propofol in PACU (OR = 2.14, 95% CI: 1.49 ~ 3.06, P < 0.001) were risk factors for APH. Intraoperative use of dexmedetomidine (OR = 0.66, 95% CI: 0.49 ~ 0.89, P = 0.007) was a protective factor. Higher baseline SBP (OR = 0.90, 95% CI: 0.89 ~ 0.92, P < 0.001) also showed some correlation with APH.

CONCLUSIONS

The risk of acute postoperative hypertension increased with age over 65 years, female patients, intraoperative hypertension and restlessness during anesthesia recovery. Intraoperative use of dexmedetomidine was a protective factor for APH.

Effects of Dexmedetomidine and ACE Genotype on Cardiovascular Response During the Decannulation Period of General Anesthesia in Patients With Essential Hypertension

PURPOSE

This study investigated the effects of dexmedetomidine on cardiovascular response during the decannulation period of general anesthesia in patients with different genotypes of angiotensin-converting enzyme (ACE) and essential hypertension.

METHODS

The present study enrolled patients with essential hypertension and American Society of Anesthesiologists class II or III who were scheduled to undergo abdominal surgery under general anesthesia. Patients were assigned to 1 of 6 groups according to ACE genotype, as detected by polymerase chain reaction-restriction fragment length polymorphism, as follows: DD; ID; II; and DD, ID, and II each with dexmedetomidine (Dex). Dexmedetomidine was intravenously infused at 0.5 μg/kg/h for 30 min before the end of surgery in groups DD (Dex), ID (Dex), and II(Dex). Anesthesia was induced and maintained by the same anesthetics in all patients. Systolic and diastolic blood pressure, heart rate (HR), ECG, and rate-pressure product were recorded before anesthesia induction; at 30 min before the end of surgery; at the end of surgery; and at 0, 1.5, 5, and 10 min after extubation.

FINDINGS

A total of 210 patients were enrolled (n = 35 per genotype). After extubation, systolic and diastolic blood pressure, HR, and RPP were increased markedly from baseline in groups DD, ID, and II; the increases were greater in groups DD and ID than in group II. No significant changes in blood pressure, HR, or RPP were found, and proper sedative was achieved in groups DD (Dex), ID (Dex), and II(Dex). The prevalences of cardiac arrhythmia were higher in groups DD and ID than in groups II, DD (Dex), ID (Dex), and II(Dex).

IMPLICATIONS

Patients essential hypertension and the ACE D allele had a strong hemodynamic response to tracheal extubation, on which dexmedetomidine was found to have both a prevention and treatment effect.

Efficacy of Combination of Esmolol and Diltiazem for Attenuating Hemodynamic Response to Laryngoscopy and Intubation: A Prospective Randomized Study

Background:

Laryngoscopy and tracheal intubation (LTI) are known to release catecholamines resulting in rise in heart rate (HR) and blood pressure. Various drugs have been studied till date to attenuate the sympathomimetic effects of laryngoscopy and intubation.

Aims:

The aim is to study the effect and safety of esmolol, diltiazem, and their combination on pressor response of laryngoscopy and intubation.

Setting and Design:

This prospective, randomized double-blind study was designed to assess the efficacy of the combination of esmolol and diltiazem and compare it with esmolol and diltiazem when used alone, for attenuating the pressor response to laryngoscopy and intubation.

Materials and Methods:

One hundred twenty-four adult patients of physical status American Society of Anesthesiologists Classes I and II posted for elective surgery under general anesthesia requiring endotracheal intubation were randomly allocated (using computer-generated random numbers) into four groups of 31 each, in a double-blind fashion, to receive the test drug, i.e., saline (control), diltiazem (0.2 mg/kg), esmolol (1.5 mg/kg), or a combination (diltiazem [0.1 mg/kg] and esmolol [0.75 mg/kg]). The test drug was administered intravenously as a bolus after 1 min of injecting the muscle relaxant. LTI was performed after 2 min of the test drug. Hemodynamic data – HR, systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) – were recorded at 1 min intervals after induction, until laryngoscopy and intubation, and at 1, 2, 3, 4, 5, and 10 min thereafter.

Statistical Analysis:

Statistical analysis was performed using one-way analysis of variance (ANOVA) for comparison among and between the groups. The Bonferroni's correction was applied when a significant difference was found between groups after applying ANOVA. Results were considered statistically significant at P ≤ 0.05.

Results:

In the control and diltiazem groups, a significant increase in HR (P ≤ 0.05) was observed after laryngoscopy. Esmolol and combination groups were associated with a significant fall in HR after administration of the test drug, and no significant rise was noted after laryngoscopy. HR was significantly less in the combination and esmolol groups as compared to the control till 5 min after LTI. As compared with the control, all the other groups were associated with a fall in SBP after the test dose, and this lasted for 5 min (P < 0.001) after laryngoscopy in the esmolol and combination groups and for 1 min (P < 0.001) in the diltiazem group. All groups were associated with a significant rise in DBP and MAP for 1–2 min after LTI (P < 0.001), except the combination group in which no change was noted. DBP and MAP were significantly less in the combination group as compared to the control, from 1 min after giving the test dose till 5 min (P < 0.001) after LTI.

Conclusion:

Although esmolol and combination groups were both effective in controlling the increase in HR and SBP, only the combination group was effective in controlling the rise in DBP and MAP after LTI. HR, SBP, DBP, and MAP were significantly less in the combination group as compared to the control till 5 min after LTI. We recommend a combination of esmolol and diltiazem in appropriate doses for effectively attenuating the rise in HR and blood pressure responses during LTI.

A Comparative Study of Dexmedetomidine and Diltiazem for Attenuating Pressor Responses to Laryngoscopy and Endotracheal Intubation: A Double-blind, Randomized Study

CONTEXT

Endotracheal intubation has been suggested to be one of the most invasive stimuli in anesthesia, particularly during induction and after tracheal intubation. The present study aims to evaluate the efficacy of dexmedetomidine as compared to diltiazem on hemodynamic response to laryngoscopy and intubation.

AIMS

To assess and compare the hemodynamic response of dexmedetomidine as compared to diltiazem in patients undergoing laryngoscopy and intubation and rate and type of side effects of the drugs if any.

SETTINGS AND DESIGN

This study design was a prospective, randomized, and double-blind trial.

SUBJECTS AND METHODS

The patients were randomly allocated into three groups: Group I (control), Group II (dexmedetomidine), and Group III (diltiazem) of 45 patients each. Group I (n = 45): 0.9% NaCl 10 ml was given to the patients over 10 min before intubation in Group I (control). Group II (n = 45): injection dexmedetomidine (0.5 μg/kg) in 10 ml normal saline was given to the patients over 10 min before intubation. Group III (n = 45): injection diltiazem (0.3 mg/kg) in 10 ml normal saline was given to the patients over 10 min before intubation.

STATISTICAL ANALYSIS USED

The data so collected were subjected to statistical analysis using Statistical Package for the Social Sciences version 15.0.

RESULTS

Mean percentage increase in systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) following intubation was 17.90%, 19.96%, and 19.04%, respectively, in control group, 9.04%, 6.32%, and 7.53%, respectively, in dexmedetomidine group, and 12.30%, 10.32%, and 11.14%, respectively, in diltiazem groups. Statistically, there was a significant difference in postintubation SBP, DBP, and MAP of the three groups (P < 0.001). Dexmedetomidine at a dose of 0.5 μg/kg showed to have a better attenuation of pressor response as compared to diltiazem at a dose of 0.3 μg/kg.

CONCLUSIONS

Both dexmedetomidine and diltiazem were safe and effective in attenuating the hemodynamic response following laryngoscopy and endotracheal intubation; however, between two trial drugs, dexmedetomidine had a better response.

Myocardial protective effects of dexmedetomidine in patients undergoing cardiac surgery: A meta-analysis and systematic review

Arrhythmias are the common complications following cardiac surgery and contribute to hemodynamic instability, cognitive impairment, thromboembolic events, and congestive heart failure. Prevention of atrial fibrillation following cardiac surgery reduces morbidity and among the many available preventive approaches dexmedetomidine shows many positive effects on cardiovascular stability. Even though many studies indicated the beneficial effects of dexmedetomidine, the power of the analysis and conclusion of these studies is rather weak due to relatively smaller number of patients in these studies. In the present meta-analysis, we included a large number of patients, both children and adults, undergoing cardiac surgery, to address the efficacy of dexmedetomidine. Several databases were searched to identify clinical studies comparing the efficacy of dexmedetomidine in myocardial protection in patients undergoing cardiac surgery. Cardiac function related parameters including heart rate, blood pressure, tachycardia, arrhthmias, and bradycardia were measured. In accordance with the selection criteria, a total of 18 studies published between 2003 and 2016, with a total of 19,225 patients were included in the present meta-analysis. Dosage of dexmedetomidine was in the range of 0.5-1 µg/kg body weight loading followed by continuous infusion at a rate of 0.2-0.7 µg/kg/h. Dexmedetomidine treatment was found to lower heart rate, systolic blood pressure, incidence of tachycardia and arrhythmias in both adult and pediatric patients, but elevated the risk of bradycardia. In conclusion, results of this meta-analysis indicate that dexmedetomidine is an efficacious cardioprotective drug in adults and children undergoing cardiac surgery.

Effects of preanesthetic dexmedetomidine on hemodynamic responses to endotracheal intubation in elderly patients undergoing treatment for hypertension: a randomized, double-blinded trial

Background

Dexmedetomidine is an alpha-2 adrenergic agonist with sedative, anxiolytic, and analgesic properties. This study was designed to evaluate the inhibitory effects of preoperative administration of 0.5 µg/kg dexmedetomidine on hemodynamic responses caused by endotracheal intubation in elderly patients undergoing treatment for hypertension.

Methods

Forty elderly (≥ 65 years old) patients who had been receiving hypertension treatment, had American Society of Anesthesiologists physical status II, and were scheduled to undergo elective noncardiac surgery were randomly selected and assigned to 2 groups. Group C received normal saline and group D received 0.5 µg/kg dexmedetomidine intravenously over 10 min just before endotracheal intubation. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) were recorded preoperatively in the ward, immediately after study drug administration, and at 1, 3, and 5 min after endotracheal intubation.

Results

Compared to group C, group D showed significantly lower SBP and MAP at 1, 3, and 5 min as well as significantly lower DBP and HR at 3 and 5 min after endotracheal intubation.

Conclusions

In elderly patients receiving hypertension treatment, a single preanesthetic dose of dexmedetomidine (0.5 µg/kg) effectively suppressed the hemodynamic responses to endotracheal intubation.

Comparison of the efficacy of lornoxicam and fentanyl in attenuating the hemodynamic response to laryngoscopy and intubation

BACKGROUND AND OBJECTIVES

Laryngoscopy and intubation elicits huge spectrum of stress response which is hazardous in high-risk patients. Many drugs and techniques have been used to attenuate the stress response. Lornoxicam 16 mg is a potent nonsteroidal anti-inflammatory drug agent with analgesic potency equivalent to morphine 10 mg, fentanyl 100 μg and tramadol 100 mg. Lornoxicam has been found to attenuate stress response in some studies. We compared the lornoxicam with fentanyl in attenuating stress response.

MATERIALS AND METHODS

A double blind randomized controlled study was conducted on 60 adult patients of American Society of Anesthesiologist physical status 1 and 2. Group L (n = 30) receives injection lornoxicam 16 mg intravenous 30 min before induction, Group F (n = 30) receives injection fentanyl 2 μg/kg during induction. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and heart rate (HR) were recorded baseline (BL), before induction, every minute up to 5 min and at 10 min after intubation.

RESULTS

After intubation, there is a gradual decrease in SBP and DBP in both groups. The MAP was also comparable between the two groups except at 5 min and 10 min during which MAP recovered toward BL in Group L where as it remained low in Group F which was statistically significant (P < 0.05). Both the drugs have successfully attenuated the HR response.

CONCLUSION

Lornoxicam successfully attenuated the hemodynamic response to laryngoscopy and endotracheal intubation and is equally efficacious as fentanyl.

Effect of Nicardipine on Haemodynamic and Bispectral Index Changes following Endotracheal Intubation

We investigated the effect of IV nicardipine on haemodynamic and bispectral index responses to the induction of general anaesthesia and intubation. Forty patients were randomly allocated to two groups of 20 to receive normal saline or nicardipine 15 μg/kg IV 30 s after induction. Ninety seconds later, tracheal intubation was performed. Systolic blood pressure, heart rate and bispectral index were measured at baseline, 1 min after induction, pre-intubation, and every minute until 5 min after endotracheal intubation. Rate–pressure product values were calculated. In the nicardipine group, systolic blood pressure decreased compared with the control group, and heart rate increased compared with the control group. Bispectral index and rate–pressure product showed no differences between the two groups. In conclusion, the administration of 15 μg/kg nicardipine IV does not affect anaesthetic depth in response to the induction of general anaesthesia and intubation.

Effects of nicardipine on the onset time and intubation conditions of rocuronium-induced neuromuscular blockade

STUDY OBJECTIVE

The objective of this study was to identify the effects of nicardipine on neuromuscular blockade of rocuronium, such as the onset time and intubation conditions, using a nicardipine dose that attenuates cardiovascular responses during endotracheal intubation.

DESIGN

Randomized, double-blinded, placebo-controlled clinical comparison was used as the design of this study

SETTING

The study was conducted at the operating room of a university hospital.

PATIENTS

Participants of this study comprise 78 American Society of Anesthesiologists physical status 1 and 2 patients, aged 18 to 60 years who were undergoing elective surgery under general anesthesia.

INTERVENTIONS

The nicardipine group was given an intravenous bolus of 20 μg/kg nicardipine before tracheal intubation: the control group was given an intravenous bolus of a comparable volume of normal saline before tracheal intubation.

MEASUREMENTS

Using a TOF-Watch SX monitor, the time from the end of the injection of rocuronium to maximum depression of T1 (onset time) was measured. Intubation was performed 1 minute after rocuronium administration, and the status of the intubation conditions was assessed. The mean blood pressure and heart rate were each measured after endotracheal intubation. Rate pressure product values were also calculated.

MAIN RESULTS

Intubation conditions were clinically acceptable in 37 (94.9%) of 39 patients in group N compared with 29 (74.4%) of 39 in group C (P < .05). The onset time of rocuronium was significantly faster in group N than in group C (P < .05). The mean blood pressure was significantly lower in group N than in group C (P < .05). The heart rate was significantly higher in group N than in group C (P < .05). Rate pressure product values showed no significant difference between the two groups (P > .05).

CONCLUSIONS

Pretreatment with 20 μg/kg nicardipine improves intubation conditions, shortens the onset time of rocuronium, and attenuates cardiovascular responses to tracheal intubation.

Optimal effect-site concentration of remifentanil for minimizing cardiovascular changes caused by fiberoptic nasotracheal intubation

BACKGROUND

Endotracheal intubation induces clinically adverse cardiovascular changes. Various pharmacological strategies for controlling these responses have been suggested with opioids being widely administered. In this study, the optimal effect-site concentration (Ce) of remifentanil for minimizing hemodynamic responses to fiberoptic nasotracheal intubation was evaluated.

METHODS

Thirty patients, aged 18-63 years, scheduled for elective surgery were included. Anesthesia was induced with a propofol and remifentanil infusion via target-controlled infusion (TCI). Remifentanil infusion was initiated at 3.0 ng/mL, and the response of each patient determined the Ce of remifentanil for the next patient by the Dixon up-and-down method at an interval of 0.5 ng/mL. Rocuronium was administered after propofol and remifentanil reached their preset Ce; 90 seconds later fiberoptic nasotracheal intubation was initiated. Non-invasive blood pressure and heart rate (HR) were measured at pre-induction, the time Ce was reached, immediately before and after intubation, and at 1 and 3 minutes after intubation. The up-and-down criteria comprised a 20% change in mean blood pressure and HR between just prior to intubation and 1 minute after intubation.

RESULTS

The median effective effect-site concentration (EC₅₀) of remifentanil was 3.11 ± 0.38 ng/mL by the Dixon's up-and-down method. From the probit analysis, the EC₅₀ of remifentanil was 3.43 ng/mL (95% confidence interval, 2.90-4.06 ng/mL). In PAVA, the EC50 and EC95 of remifentanil were 3.57 ng/mL (95% CI, 2.95-3.89) and 4.35 ng/mL (95% CI, 3.93-4.45). No remifentanil-related complications were observed.

CONCLUSIONS

The EC₅₀ of remifentanil for minimizing the cardiovascular changes and side effects associated with fiberoptic nasotracheal intubation was 3.11-3.43 ng/mL during propofol TCI anesthesia with a Ce of 4 ug/mL.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Attenuation of Hemodynamic Responses to Laryngoscopy and Tracheal Intubation: Propacetamol versus Lidocaine-A Randomized Clinical Trial

The purpose of this study is to assess the effects of propacetamol on attenuating hemodynamic responses subsequent laryngoscopy and tracheal intubation compared to lidocaine. In this randomized clinical trial, 62 patients with the American Anesthesiologists Society (ASA) class I/II who required laryngoscopy and tracheal intubation for elective surgery were assigned to receive propacetamol 2 g/I.V./infusion (group P) or lidocaine 1.5 mg/kg (group L) prior to laryngoscopy. Systolic and diastolic blood pressures (SBP, DBP), mean arterial pressure (MAP), and heart rate (HR) were recorded at baseline, before laryngoscopy and within nine minutes after intubation. In both groups P and L, MAP increased after laryngoscopy and the changes were statistically significant (P < 0.001). There were significant changes of HR in both groups after intubation (P < 0.02), but the trend of changes was different between two groups (P < 0.001). In group L, HR increased after intubation and its change was statistically significant within 9 minutes after intubation (P < 0.001), while in group P, HR remained stable after intubation (P = 0.8). Propacetamol 2 gr one hour prior intubation attenuates heart rate responses after laryngoscopy but is not effective to prevent acute alterations in blood pressure after intubation.

Pharmacological agents for preventing morbidity associated with the haemodynamic response to tracheal intubation

BACKGROUND

Several drugs have been used in attenuating or obliterating the response associated with laryngoscopy and tracheal intubation. These changes are of little concern in relatively healthy patients but can lead to morbidity and mortality in the high risk patient population.

OBJECTIVES

The primary objective of this review was to determine the effectiveness of pharmacological agents in preventing the morbidity and mortality resulting from the haemodynamic changes in response to laryngoscopy and tracheal intubation in adult patients aged 18 years and above who were undergoing elective surgery in the operating room setting.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2011, Issue 6), MEDLINE (1950 to June 2011), EMBASE (1980 to June 2011), and the bibliographies of published studies. We reran our search from June 2011 to December 2012 and will deal with these studies when we update the review.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared a drug used as an intervention for preventing or attenuating the haemodynamic response to tracheal intubation to a control group, and that mentioned mortality, major morbidity, arrhythmia or electrocardiogram (ECG) evidence of ischaemia in the methodology, results, or discussion section of the reports.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted the outcome data.

MAIN RESULTS

We included 72 RCTs. The included trials studied the effects of 32 drugs belonging to different pharmacological groups. Only two trials mentioned the primary outcome of morbidity and mortality related to the haemodynamic response to tracheal intubation. Of the secondary outcomes, 40 of the included trials observed arrhythmia only, 11 observed myocardial ischaemia only and 20 observed both arrhythmias and myocardial ischaemia. Arrhythmias were observed in 2932 participants and myocardial ischaemia in 1616 participants. Arrhythmias were observed in 134 out of 993 patients in the control group compared to 80 out of 1939 in the intervention group. The risk of arrhythmias was significantly reduced with pharmacological interventions in the pooled data (Peto odds ratio (OR) 0.19, 95% CI 0.14 to 0.26, P < 0.00001, I(2)= 47%). Local anaesthetics, calcium channel blockers, beta blockers and narcotics reduced the risk of arrhythmia in the intervention group compared to the control group. Myocardial ischaemia was observed in 21 out of 604 patients in the control group compared to 10 out of 1012 in the treatment group; the result was statistically significant (Peto OR 0.45, 95% CI 0.22 to 0.92, P = 0.03, I(2) = 19%). However, in subgroup analysis only local anaesthetics significantly reduced the ECG changes indicating ischaemia, but this evidence came from one study. The majority of the studies had a negative outcome. Hypotension and bradycardia were reported with 40 µg kg(-1) intravenous alfentanil, chest rigidity with 75 ug kg(-1) alfentanil, and increased bronchomotor tone with sympathetic blockers.There were 17 studies which included high risk patients. Pharmacological treatment in this group resulted in the reduction of arrhythmias when the data from nine trials looking at arrhythmias were pooled (Peto OR 0.18, 95% CI 0.05 to 0.59, P = 0.005, I(2) = 80%). The analysis from four studies was not included. Three of these trials looked at the effect of sympathetic blockers but arrhythmias or myocardial ischaemia was observed throughout the perioperative period in two studies and some patients had arrhythmias due to atropine premedication in the third study. In the fourth study the authors mentioned myocardial ischaemia in the objectives section but did not report it in the results.

AUTHORS' CONCLUSIONS

The risk of arrhythmias associated with tracheal intubation was significantly reduced with pre-induction administration of local anaesthetics, calcium channel blockers, beta blockers and narcotics compared to placebo. Pharmacological intervention also reduced the risk of ECG evidence of myocardial ischaemia in the pooled data. Lignocaine pretreatment showed a significant effect but evidence came from one study only. The data suggested that there may be a reduction in ECG evidence of myocardial ischaemia with beta blocker pretreatment but this difference was not statistically significant. There is a need to focus on outcomes rather than haemodynamic measurements alone when studying this response in future trials.

Comparison of fentanyl and clonidine for attenuation of the haemodynamic response to laryngocopy and endotracheal intubation

INTRODUCTION

Laryngoscopy and tracheal intubation after the induction of anaesthesia, are nearly always associated with sympathetic hyperactivity. To 'blunt' this pressor response, various methods have been tried, but very few studies have been done to assess the effects of fentanyl orI.V. clonidine on the haemodynamic response during laryngoscopy and tracheal intubation. The purpose of this study was to compare these agents, to find the drug which was best suited for this purpose and the most favourable time for its administration.

METHODS

This was a prospective study which involved 3 groups of patients. The patients in group-1 (control) were given normal saline and the groups 2 and 3 were given i.v. fentanyl and clonidine respectively. Each group had 50 patients who presented for elective, non-cardiovascular surgeries. All the patients were ASA-1 or ASA-II and were operated in PESIMSR, Kuppam.

RESULTS

The heart rate rise was 48.07% in the control group, whereas it was significantly lower in the fentanyl (II) 27.75% and the clonidine groups (III) 12.57% (p<0.001). In the control group, the systolic blood pressure increased maximally after 5 minutes (42.62%) i.e., immediately after the laryngoscopy and the intubation. It decreased gradually over 10 minutes (17.39%). With the administration of fentanyl, the maximum increase as compared to the preinduction value was 9.91%, but it was only 7.38% in the clonidine group. Both, when they were compared with the control, showed a significant suppression (P<.001), with clonidine showing better results. The maximum increase in the diastolic blood pressure was 30.12% in the control group (P<.001) at 5 min and it was 18.22%, and 6.15% in the fentanyl and the clonidine groups respectively, with clonidine faring better again (P<.001).

INTERPRETATION AND CONCLUSION

Clonidine showed better attenuation of the sympathetic response, which is statistically highly significant and it remained so till the end of 10 minutes. Intravenous clonidine 2;g/kg which is administered 5 minutes before the laryngoscopy can be recommended to attenuate the sympathetic response to the laryngoscopy and the intubation.

Comparative prophylactic and therapeutic effects of intravenous labetalol 0.4 mg/kg and nicardipine 20 μg/kg on hypertensive responses to endotracheal intubation in patients undergoing elective surgeries with general anesthesia: a prospective, randomized, double-blind study

BACKGROUND

Laryngoscopy and tracheal intubation (LTI) after induction of general anesthesia often cause hypertension and tachycardia. Labetalol and nicardipine have been used to prevent and treat acute cardiovascular responses to LTI.

OBJECTIVE

The goal of this study was to compare the preventive and therapeutic effects of labetalol 0.4 mg/kg IV and nicardipine 20 μg/kg IV on hypertensive responses to LTI during induction of general anesthesia.

METHODS

Patients undergoing general anesthesia were randomly allocated to 4 groups. In part I (prevention), 80 patients were randomized to receive either 0.4 mg/kg of labetalol (n = 40) or 20 μg/kg of nicardipine (n = 40) 4 minutes before LTI. In part II (treatment), patients were randomized to receive 0.4 mg/kg of labetalol (n = 40) or 20 μg/kg of nicardipine (n = 40) after LTI if hypertension occurred. The number of additional study drug doses required by patients with hypertension (parts I and II) and time to return to normotension (part II) were recorded. Mean arterial pressure and heart rate were monitored, and rate-pressure product was calculated. Adverse events were also monitored.

RESULTS

A total of 130 patients (72 patients in part I and 58 patients in part II) were included in the analysis. In parts I and II, the number of patients who required additional doses of the study drug because of persistent hypertension was lower in the nicardipine groups than in the labetalol groups (P < 0.05). Mean arterial pressure was lower and heart rate was significantly higher over time in the nicardipine groups compared with the labetalol groups (P < 0.05) in parts I and II. In part II, time to return to normotension was shorter in the nicardipine treatment group than in the labetalol treatment group (61 [21] vs 130 [46] seconds; P = 0.01). No statistical differences were observed in the incidence of adverse events except for tachycardia in part I (2 cases in the labetalol prevention group vs 18 cases in the nicardipine prevention group; P = 0.01).

CONCLUSIONS

Patients who received nicardipine were less likely to require additional doses for either the prevention or treatment of hypertensive responses to LTI and responded to the study drug more rapidly than patients who received labetalol for the treatment of hypertensive responses to LTI. However, labetalol was associated with a lower incidence of tachycardia and less of an increase in rate-pressure product when used for the prevention of hypertension during LTI.

Comparison of esmolol and labetalol, in low doses, for attenuation of sympathomimetic response to laryngoscopy and intubation

Objective:

The present study compared the efficacy of esmolol and labetalol, in low doses, for attenuation of sympathomimetic response to laryngoscopy and intubation.

Design:

Prospective, randomized, placebo controlled, double-blinded study.

Setting:

Operation room.

Patients and Methods:

75 ASA physical status I and II adult patients, aged 18-45 years undergoing elective surgical procedures, requiring general anesthesia and orotracheal intubation.

Interventions:

Patients were allocated to any of the three groups (25 each)-Group C (control)10 ml 0.9% saline i.v. Group E (esmolol) 0.5 mg/kg diluted with 0.9% saline to 10 ml i.v. Group L (labetalol) 0.25 mg/kg diluted with 0.9% saline to 10 ml i.v. In the control group 10 ml of 0.9% saline was given both at 2 and 5 min prior to intubation. In the esmolol group 0.5 mg/kg of esmolol (diluted with 0.9% saline to 10 ml) was given 2 min prior and 10 ml of 0.9% saline 5 min prior to intubation. In the labetalol group 10 ml of 0.9% saline was administered 2 min prior and 0.25 mg/kg of labetalol (diluted with 0.9% saline to 10 ml) 5 min prior to intubation. All the patients were subjected to the same standard anesthetic technique.

Measurements:

Heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded prior to induction, at time of intubation and 1, 3, 5, and 10 min after intubation. Mean arterial pressure (MAP) and rate pressure product (RPP) were calculated. Abnormal ECG changes were also recorded.

Results:

Compared to placebo and esmolol (0.5 mg/kg), labetalol (0.25 mg/kg) significantly attenuated the rise in heart rate, systolic blood pressure, and RPP during laryngoscopy and intubation. However, the difference was not statistically significant among the values for DBP and MAP.

Conclusion:

In lower doses, labetalol (0.25 mg/kg) is a better agent than esmolol (0.5 mg/kg) in attenuating the sympathomimetic response to laryngoscopy and intubation.

Hemodynamics in coronary artery bypass surgery: effects of intraoperative dexmedetomidine administration

OBJECTIVE

Dexmedetomidine is an α2-receptor agonist which is increasingly being used in coronary artery bypass grafting (CABG) surgery due to its suppressive effect on the stress responses against intubation and surgery. In this study effects of dexmedetomidine administration as an adjuvant agent during induction and maintenance of anesthesia on intraoperative hemodynamic changes were studied in patients undergoing CABG.

METHODS

A total of 20 patients undergoing CABG were included in the study. At the beginning dexmedetomidine infusion of 1 µg/kg body weight (BW)/h was performed for 10 min. After this the infusion dosage of dexmedetomidine was decreased to 0.2-0.4 µg/kgBW/h, 0.15 mg/kgBW of cisatracurium was administered for intubation and 0.5 MAC (minimum alveolar concentration) sevoflurane was administered as a volatile anesthetic. Heart rate (HR), mean arterial pressure (MAP), mean pulmonary artery pressure (MPAP), cardiac output (CO), systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) were recorded 10 min after dexmedetomidine infusion, following intubation, during skin incision and sternotomy, before and after the bypass and in the postoperative period.

RESULTS

With dexmedetomidine infusion HR and MAP were found to be moderately decreased in comparison to baseline values and no severe bradycardia or hypotension requiring intervention occurred. No increase in HR and MAP values were recorded during sternotomy and bypass. The MPAP evaluation showed no difference between the preoperative and intraoperative values (p>0.05). The cardiac output (CO) was found to be low starting from the time of skin incision to just before the bypass, compared to preoperative values (p<0.05) and SVR was moderately decreased with initial high dose infusion and after that increased to baseline values (p<0.05).

CONCLUSION

Dexmedetomidine can be safely used in CABG operations delivering a stable hemodynamic status throughout the operative period.

Complications of emergency tracheal intubation: hemodynamic alterations--part I

Emergency airway management outside the elective operating room presents considerable risks to the patient and significant challenges to the practitioner. Complications and adverse consequences are commonplace, yet they have not received their justified discussion or scrutiny in the literature. This review will discuss potentially life-threatening complications partitioned into 2 broad categories: hemodynamic and airway. Part 1 will focus on alterations in the heart rate and blood pressure, new onset cardiac dysrhythmias and cardiac arrest. Part 2 will explore airway related consequences such as hypoxemia, esophageal intubation, multiple intubation attempts, and aspiration.

Which is responsible for the haemodynamic response due to laryngoscopy and endotracheal intubation? Catecholamines, vasopressin or angiotensin?

BACKGROUND AND OBJECTIVE

We have investigated the concentrations of epinephrine, norepinephrine, vasopressin and angiotensin converting enzyme activity to explore the role of these mediators in the neuroendocrine response to laryngoscopy and tracheal intubation.

METHODS

One hundred (50 male, 50 female) ASA I patients aged 20-50 yr (mean+/-SEM; 35.59+/-0.99) were included in the study. They were undergoing elective surgery under standard anaesthesia induction and maintenance using tracheal intubation. Plasma concentrations of epinephrine, norepinephrine and vasopressin as well as plasma angiotensin converting enzyme activity were determined at four time points, before (T1) and after (T2) induction, and 2 (T3) and 5 min (T4) after intubation. Blood pressure and heart rate were recorded at corresponding times to reveal if any correlation existed between haemodynamic parameters and neuroendocrine response.

RESULTS

Heart rate increased after induction and intubation (P<0.05) and decreased significantly at T4 (P<0.05). Systolic blood pressure decreased significantly (P<0.05) after induction and increased slightly after intubation decreasing to below baseline value (P<0.05) at T4. Diastolic blood pressure increased slightly after intubation and decreased significantly (P<0.05) at T4. Plasma epinephrine and norepinephrine concentrations decreased after induction and increased at T3 and T4 without reaching significance. Vasopressin concentrations increased slightly at T2 and T3 and decreased significantly at T4 (P<0.05). Angiotensin converting enzyme activity was unaffected when compared with baseline values.

CONCLUSIONS

Blood pressure, heart rate, plasma epinephrine, norepinephrine and vasopressin concentrations increased slightly in response to laryngoscopy and intubation, all returning to or below baseline 5 min later with no change in angiotensin converting enzyme activity in normotensive patients.

Hemodynamic and catecholamine response to tracheal intubation: direct laryngoscopy compared with fiberoptic intubation

STUDY OBJECTIVE

To compare the stress response following tracheal intubation using direct laryngoscopy to that using fiberoptic bronchoscopy technique.

DESIGN

Randomized, prospective study.

SETTING

Operating rooms in a teaching hospital.

PATIENTS

51 ASA physical status I and II patients who were scheduled for an elective surgery with general anesthesia.

INTERVENTIONS

Patients were randomly assigned to receive either direct laryngoscopy or fiberoptic orotracheal intubation, as part of general anesthesia. A uniform protocol of anesthetic medications was used.

MEASUREMENTS

Blood pressure and heart rate were measured before induction, before endotracheal intubation, and 1, 2, 3, and 5 minutes afterwards. Catecholamine (epinephrine and norepinephrine) blood samples were drawn before the induction, and 1 and 5 minutes after intubation.

MAIN RESULTS

Duration of intubation was shorter in the direct laryngoscopy group (16.9 (16.9 +/- 7.0 sec, range 8 to 40) compared with the fiberoptic intubation group (55.0 +/- 22.5 sec, range 29 to 120), p < 0.0,001. In both groups, blood pressure and heart rate were significantly increased at 1, 2, and 3 minutes after intubation, but there was no significant difference between the two study groups. Catecholamine levels did not increase after intubation and did not correlate with the hemodynamic changes.

CONCLUSIONS

The use of either direct laryngoscopy or fiberoptic bronchoscopy produces a comparable stress response to tracheal intubation. Catecholamine levels do not correlate with the hemodynamic changes.

Rapid sequence induction: a national survey of practice

We performed a national postal survey exploring anaesthetists' practice in rapid sequence induction. All respondents used pre-oxygenation, although the technique employed, and its reliability, varied. Thiopental and succinylcholine, given after waiting for signs of loss of consciousness, were the most widely used drugs for rapid sequence induction. Propofol and rocuronium were used by more than a third of respondents, and most respondents (75%) also routinely administered an opioid. Cricoid pressure was used universally but the practice of its application varied widely. The commonest aids used if intubation was difficult were the gum elastic bougie, the long laryngoscope blade and the laryngeal mask. After failed intubation, approximately half of respondents would maintain the supine position. Failure to intubate at rapid sequence intubation had been seen by 45% of respondents but harm was uncommon. In contrast, 28% had seen regurgitation, which frequently led to considerable harm and to three deaths. In spite of this, practice of a failed intubation drill was uncommon (15%) and anaesthetic assistants were rarely known to practice application of cricoid pressure. Consultants were less likely than trainees to use rocuronium as a muscle relaxant, and more likely to choose morphine if administering an opioid. They were less likely to practice a failed intubation drill. Other aspects of practice varied little between grades. This survey suggests that many anaesthetists do not follow best practice when performing a rapid sequence induction.

Diltiazem to treat sinus tachycardia in critically ill patients: a four-year experience

OBJECTIVES

To determine whether an intravenous infusion of the calcium channel blocker diltiazem was effective and safe in treating sinus tachycardia in critically ill adult patients with contraindications to beta-blockers or in whom beta-blockers were ineffective.

DESIGN

Retrospective chart review.

SETTING

University medical center.

PATIENTS

The records of 171 surgical intensive care unit patients with sinus tachycardia treated with intravenous diltiazem were evaluated.

INTERVENTIONS

In all patients with sinus tachycardia (heart rate >100 beats/min), heart rate control with intravenous diltiazem was attempted after adequate intravascular volume expansion, pain, and anxiety control. In all patients, beta-blockade either was contraindicated or (in 7%) had failed. Intravenous diltiazem was administered as a slow 10-mg bolus dose (0.1-0.2 mg/kg ideal body weight), and then an infusion was started at 5 or 10 mg/hr and increased up to 30 mg/hr, as needed, to decrease heart rate to <100 beats/min. Variables retrospectively collected included demographic data, preinfusion blood pressure, mean arterial pressure, heart rate, and preinfusion pressure-rate quotients (pressure-rate quotient = mean arterial pressure / heart rate). Intravenous bolus dose, when given, and diltiazem infusion rate and time necessary to achieve the target heart rate also were recorded. The lowest heart rate recorded within 24 hrs from the initiation of the infusion and the time necessary to achieve the lowest heart rate after beginning the infusion were recorded.

MEASUREMENTS AND RESULTS

Of 171 patients studied, 97 (56%) were classified as responders. Multiple linear regression suggested that response could be predicted by age, pressure-rate quotients, baseline mean arterial pressure, and central nervous system failure. In the responders, a heart rate <100 beats/min was achieved in an average of 2 hrs, at a mean diltiazem infusion of 13.3 mg/hr. The lowest rate reached by the responders in a 24-hr period averaged 86 beats/min and was achieved in 4.8 hrs with a mean infusion rate of 14.8 mg/hr. Both target and lowest rate values were statistically different from baseline heart rate.

CONCLUSION

Diltiazem was effective in achieving short-term control of heart rate in 56% of the patients, virtually without adverse effects, where beta-blockade was contraindicated or ineffective.

Massive esophageal variceal hemorrhage triggered by complicated endotracheal intubation

Esophageal variceal hemorrhage is frequently a catastrophic event. The specific events that trigger variceal rupture are not well understood. Acute elevations in systemic blood pressure and increased splanchnic blood flow, however, may lead to increased intravariceal pressure followed by variceal rupture and hemorrhage. This report describes a strong temporal association between complicated endotracheal intubation and abrupt onset of life-threatening variceal hemorrhage. A 52-year-old man with a history of portal hypertension was intubated emergently for airway protection because of respiratory insufficiency due to sepsis. Intubation was complicated by initial inadvertent esophageal intubation and by a peak mean arterial blood pressure of 155 mmHg. At the conclusion of the procedure, the patient sustained large volume hematemesis due to esophageal variceal rupture. This case suggests a risk of triggering variceal hemorrhage as a result of intubation-induced increase in blood pressure. A number of agents, including fentanyl, have been shown to be effective in attenuating the cardiovascular response to intubation. This case report provides strong evidence in support of administering fentanyl, or a suitable alternative adjunctive medication, before intubation of patients with documented portal hypertension and a history of esophageal variceal hemorrhage.

The use of esmolol, nicardipine, or their combination to blunt hemodynamic changes after laryngoscopy and tracheal intubation

Laryngoscopy and tracheal intubation (LTI) often provoke an undesirable increase in blood pressure (BP) and/or heart rate (HR). We tested the premise that nicardipine (NIC) and esmolol (ESM) in combination (COMB) would oppose both. Adult surgical patients received pretreatment (randomized) with IV bolus NIC 30 microg/kg (n = 31), ESM 1.0 mg/kg (n = 34), or COMB (one-half dose each, n = 32). Peak BP and HR after LTI were compared with controls (CONT; n = 35) with no pretreatment. Anesthetic induction was standardized: IV thiopental (5-7 mg/kg), fentanyl (1-2 microg/kg), and succinylcholine (1.5 mg/kg). Systolic (S), diastolic (D), and mean (M) BP and HR awake before pretreatment (baseline) were similar in all test groups. No patient was treated for hypotension, bradycardia, or tachycardia after pretreatment or anesthetic induction. Peak HR after LTI was increased versus baseline in CONT and all test groups, but did not differ from CONT among the test groups. Peak SBP and DBP increased versus baseline in CONT, and with ESM and NIC, but not COMB. Peak SBP, DBP, and MBP were increased with ESM versus COMB, and peak DBP with ESM versus NIC. Compared with no pretreatment before the IV induction of general anesthesia, the peak increase in BP after LTI is best blunted by the combination of nicardipine and ESM, compared with either drug alone. No single drug or combination in the doses tested opposed increased HR.

IMPLICATIONS

Compared with no pretreatment before the IV induction of general anesthesia, the peak increase in blood pressure after laryngoscopy and tracheal intubation is best blunted by the combination of nicardipine and esmolol, compared with either drug alone. No single drug or combination in the doses tested opposed increased heart rate.

Optimal dose of nicardipine for maintenance of hemodynamic stability after tracheal intubation and skin incision

To determine the optimal dose of nicardipine (N) for maintenance of hemodynamic stability during the postinduction period, we designed a randomized, double-blind, placebo-controlled, dose-ranging study using four different doses of N administered after a standardized anesthetic induction sequence. A total of 106 patients were assigned to one of the following treatment groups: saline (control), N 0.5 mg (N0.5), N 1 mg (N1), N 2 mg (N2), and N 4 mg (N4). The study medication was administered intravenously (I.V.) in 2.5 mL of saline over 30 s 2 min before laryngoscopy. Mean arterial pressure (MAP) and heart rate (HR) were recorded at 1-min intervals for 15 min after tracheal intubation and for 5 min after skin incision. After intubation, the peak MAP values differed from the preinduction baseline MAP values by 21% +/- 20%, 9% +/- 12%, 1% +/- 13%, -10% +/- 12%, and -15% +/- 13% (mean +/- SD) in the control, N0.5, N1, N2, and N4 groups, respectively. However, the percent change in the pre- to postintubation MAP values (37% to 47%) was similar in all five groups. The highest postintubation HR values were recorded in the N4 group (P < 0.05 versus the other groups). However, the increases in MAP values after skin incision were the least in the N4 group. In conclusion, N1 I.V., administered 2 min before laryngoscopy provides optimal control of arterial blood pressure during the postinduction period.

IMPLICATIONS

Acute increases in blood pressure during anesthesia are undesirable in patients with preexisting cardiovascular diseases. This double-blind study found that the calcium-channel blocker, nicardipine, 1 mg intravenously 2 min before tracheal intubation maintained hemodynamic stability during the intraoperative period.