Impact of propofol anesthesia induction on cardiac function in low-risk patients as measured by intraoperative Doppler tissue imaging

Effects of different rates of propofol with or without S-ketamine on ventricular function in healthy cats - a randomized study

Propofol is used for anesthetic induction in cats and procedural sedation in countries where alfaxalone is not available. Studies have reported propofol-related effects in echocardiography variables in dogs and humans. However, there is a lack of echocardiography studies investigating propofol-related effects on cats. This study aimed to use echocardiography to investigate echocardiographic changes in three protocols using propofol: propofol-slow (2 mg/kg/min, PS); propofol-fast (8 mg/kg/min, PF); propofol-ketamine (S-ketamine 2 mg/kg bolus followed by propofol 2 mg/kg/min; PK) in healthy premedicated (gabapentin-buprenorphine-acepromazine; 200 mg/cat, 0.4, and 0.1 mg/kg, respectively), non-intubated cats. Echocardiographic measurements were obtained at three time points: baseline (before the administration of propofol), end of propofol titration (end-point, T0), and 15 min after T0 (T15). Propofol at a lower rate continued from T0 to T15. Echocardiographic and physiological variables included fractional shortening (FS%), ejection fraction (EF%), HR, BP, and others. Propofol requirements at T0 for PF, PS, and PK groups were 5.0 ± 0.9, 3.8 ± 0.7, and 2.4 ± 0.5 mg/kg, respectively. EF% neither change over time nor between groups. PF and PK showed a reduction in FS% at T0 (47 ± 6 to 34 ± 6 and 42 ± 6 to 36 ± 5, respectively). BP reduced significantly in PF and PS groups (136 ± 26 to 105 ± 13 and 137 ± 22 to 115 ± 15 mmHg, respectively). It is unclear whether changes in echocardiography variables were of clinical relevance related to treatment groups or a result of within-group individual responses.

Remimazolam Requires Less Vasopressor Support during Induction and Maintenance of General Anesthesia in Patients with Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement: A Retrospective Analysis from a Single Center

Introduction

We compared the hemodynamics during general anesthesia with remimazolam and conventional anesthetics in patients with severe aortic stenosis (AS).

Methods

This was a retrospective single-center analysis. We reviewed the records of 42 patients who underwent transcatheter aortic valve implantation with a transfemoral artery approach under general anesthesia from January to December 2020. Patients were divided into three groups based on the general anesthetic used for (induction/maintenance) remimazolam/remimazolam (Group R/R), propofol/sevoflurane (Group P/S), and midazolam/propofol (Group M/P). Vasopressor use (ephedrine, phenylephrine, and noradrenaline) was compared among the groups.

Results

The number of patients in each group was 15 (Group R/R), 13 (Group P/S), and 14 (Group M/P), with no significant difference in background characteristics and intraoperative vital signs. For anesthesia induction, doses of ephedrine and phenylephrine used were significantly lower in Group R/R (ephedrine [mg]: Group R/R 2 [0-4] vs. Group P/S 8 [8-12], P < 0.001, Group R/R vs. Group M/P 5 [0-15], P = 0.39; phenylephrine (mg): Group R/R 0 [0-0.08] vs. Group P/S 0.15 [0.10-0.20], P = 0.03, Group M/P 0.21 [0.04-0.40], P = 0.08). For anesthesia maintenance, the noradrenaline dose used was low in the Group R/R (noradrenaline [μg/kg/min]: Group R/R 0.019 [0.015-0.039], Group P/S 0.042 [0.035-0.045], P = 0.02, Group M/P 0.048 [0.040-0.059], P < 0.01).

Conclusion

In patients with severe AS, induction and maintenance of anesthesia with remimazolam resulted in less overall vasopressor use than conventional general anesthetics.

Comparison the Effect of Etomidate vs. Thiopentone on Left Ventricular Strain and Strain Rate at the Time of Anesthesia Induction in Patients Undergoing Elective Coronary Artery Bypass Surgery: A Randomized Double Blind Controlled Trial

Myocardial strain imaging with speckle tracking echocardiography (STE) is getting popularity because it does not depends on insonation angle and has shown good correlation with intraoperative and postoperative ventricular function in patients with coronary artery disease. The impact of thiopentone and etomidate induction on myocardial function was studied and compared on sixty patients undergoing elective coronary artery bypass grafting. Three loops for each views (apical 4 chamber, apical 2 chamber, and apical long axis ) were acquired at base line (T0) and 1 minute (T1) after induction for offline analysis. In Group T, significant increase in HR from the base line values (67.8 ± 13.8 vs 79.2 ± 15.6, p = 0.001) occurred post induction, where as in Group E it remain near to the base line (71.7 ± 8.3 vs 70.1± 8.9, p = 0.345). A reduction in mean arterial pressure (MAP) was noted in both the groups after the injection of the allocated drug. There was no significant difference in the index of contractility (ICON) (T0 vs T1: 48.7 ± 10.6 vs 47.0 ± 11.7, p = 0.120) in Group E where as in Group T there was a reduction in the ICON value (T0 vs T1: 45.0 ± 10.7 vs 41.0 ± 8.4, p = 0.005). A similar picture was also noted in systemic vascular resistance index. A significant decrease in cardiac index (CI) was seen in Group E (T0 vs T1: 2.7 ± 0.4 vs 2.5 ± 0.4, p = 0.027), however it remain near to the base line in Group T. There occurred no changes in stroke index (SI) in Group E (T0 vs T1: 38.7 ± 6 vs 37.0± 5.3, p = 0.134), where as a significant decrease was noted after injection of thiopental (T0 vs T1: 38.0 ± 6.2 vs 36.1± 4.9, p = 0.049). A significant decline in cardiac performance index (CPI) was also recorded in Group E (T0 vs T1: 0.57 ± 0.15 vs 0.52 ± 0.12, p = 0.032), and not in Group T. There was decrease in left ventricular ejection fraction (LVEF) after the injection of both the drugs (Group E, T0 vs T1: 57 ± 3.7 vs 54± 3.7, p= 0.001; and Group T, T0 vs T1: 57 ± 3.7 vs 54± 3.7, p = 0.001). In Group E, global longitudinal peak systolic strain (GLPSS) showed no change after the injection of the drug (T0 vs T1: −13.2 ± 2.2 vs −13.1± 2.3, p = 0.631). However, a significant decrease in GLPSS (T0 vs T1: −13.5 ± 1.5 vs – 10 ± 1.8, p = 0.001) after injection of thiopental. Longitudinal peak systolic strain rate (LPSSR) was significantly decreased in all echocardiographic views after the injection of respective drugs. However, the decrease in LPSSR was significantly less in Group E in comparison to Group T.

To conclude, STE provides accurate and reliable real time quantitative regional and global LV assessment. Use of thiopentone for anesthesia induction is associated with more profound impairment of LV function in comparison to etomidate as assessed by a decreased longitudinal peak systolic strain rate and global longitudinal peak systolic strain. Further studies are warranted to understand the exact clinical impact, which may influence the choice of intravenous induction agent based upon preoperative patient characteristics.

Etomidate vs propofol in coronary heart disease patients undergoing major noncardiac surgery: A randomized clinical trial

BACKGROUND

The ideal depth of general anesthesia should achieve the required levels of hypnosis, analgesia, and muscle relaxation while minimizing physiologic responses to awareness. The choice of anesthetic strategy in patients with coronary heart disease (CHD) undergoing major noncardiac surgery is becoming an increasingly important issue as the population ages. This is because general anesthesia is associated with a risk of perioperative cardiac complications and death, and this risk is much higher in people with CHD.

AIM

To compare hemodynamic function and cardiovascular event rate between etomidate- and propofol-based anesthesia in patients with CHD.

METHODS

This prospective study enrolled consecutive patients (American Society of Anesthesiologists grade II/III) with stable CHD (New York Heart Association class I/II) undergoing major noncardiac surgery. The patients were randomly allocated to receive either etomidate/remifentanil-based or propofol/remifentanil-based general anesthesia. Randomization was performed using a computer-generated random number table and sequentially numbered, opaque, sealed envelopes. Concealment was maintained until the patient had arrived in the operating theater, at which point the consulting anesthetist opened the envelope. All patients, data collectors, and data analyzers were blinded to the type of anesthesia used. The primary endpoints were the occurrence of cardiovascular events (bradycardia, tachycardia, hypotension, ST-T segment changes, and ventricular premature beats) during anesthesia and cardiac troponin I level at 24 h. The secondary endpoints were hemodynamic parameters, bispectral index, and use of vasopressors during anesthesia.

RESULTS

The final analysis included 40 patients in each of the propofol and etomidate groups. The incidences of bradycardia, hypotension, ST-T segment changes, and ventricular premature beats during anesthesia were significantly higher in the propofol group than in the etomidate group (P < 0.05 for all). The incidence of tachycardia was similar between the two groups. Cardiac troponin I levels were comparable between the two groups both before the induction of anesthesia and at 24 h after surgery. When compared with the etomidate group, the propofol group had significantly lower heart rates at 3 min after the anesthetic was injected (T₁) and immediately after tracheal intubation (T₂), lower systolic blood pressure at T₁, and lower diastolic blood pressure and mean arterial pressure at T₁, T₂, 3 min after tracheal intubation, and 5 min after tracheal intubation (P < 0.05 for all). Vasopressor use was significantly more in the propofol group than in the etomidate group during the induction and maintenance periods (P < 0.001).

CONCLUSION

In patients with CHD undergoing noncardiac major surgery, etomidate-based anesthesia is associated with fewer cardiovascular events and smaller hemodynamic changes than propofol-based anesthesia.

The Effects of Propofol on Left Ventricular Global Longitudinal Strain

Objectives

To determine if hemodynamic changes secondary to propofol administration are a result of direct myocardial depression as measured by global longitudinal strain (GLS). The authors hypothesized that propofol would cause a significant worsening in GLS, indicating direct myocardial depression.

Design

Prospective, observational.

Setting

Endoscopy suite at a single academic medical center.

Participants

Patients undergoing outpatient, elective endoscopic procedures at an outpatient clinic of a single tertiary care academic medical center.

Interventions

None.

Measurements and Main Results

Limited transthoracic echocardiograms were performed before and after patients received propofol for endoscopic procedures. Post-processing measurements included GLS, 2D (dimensional) ejection fraction (2D EF), and 3D EF. Using paired sample Student’s t test, no statistically significant change in GLS, 2D EF, or 3D EF was found despite statistically significant hypotension. In fact, there was a trend toward more negative GLS (improved myocardial function) in patients after receiving propofol.

Conclusion

We found propofol did not cause a reduction in systolic function as measured by GLS, a sensitive measure of myocardial contractility. Therefore, decreases in blood pressure after a propofol bolus in spontaneously breathing patients are likely due to decreased vascular tone and not impaired left ventricular systolic function. These results should be considered in the management of propofol-induced hypotension for spontaneously breathing patients.

Determinants of Discrepancy in the Left Ventricular Systolic Function Evaluation Between Preoperative and Intraoperative Evaluations

Unexpectedly decreased left ventricular global systolic function can be difficult to manage, even for patients undergoing elective cardiac surgery, and should prompt a multidisciplinary discussion. Therefore, in this review, we discuss the evidence describing key perioperative variables expected to influence left ventricular systolic function to facilitate this discussion.

Effect of the infusion rate of propofol on the onset time of rocuronium

BACKGROUND

Administration of propofol, especially rapid administration, decreases patient cardiac output (CO) to various degrees. CO might influence the buildup of an effective drug level within the neuromuscular junction and affect the onset time of neuromuscular blockers. The present study aimed to investigate the effects of different infusion rates of propofol on patient CO and the onset time of rocuronium.

METHODS

A total of 90 patients were randomly assigned to receive propofol (2.5 mg/kg) at an infusion rate of 480 mg/min (group A), 240 mg/min (group B), or 120 mg/min (group C). After the administration of propofol, rocuronium (0.6 mg/kg) was administered to facilitate tracheal intubation. The Finometer monitor was used to obtain the cardiovascular profile during the induction of general anesthesia. Neuromuscular relaxation was monitored by acceleromyography using the ulnar nerve at the wrist surface and electrodes with repeated single twitches. Onset time was defined as the time from the beginning of rocuronium injection until 95% twitch depression. The onset time of rocuronium in the three groups was compared using analysis of variance with the post-hoc Tukey test. A p-value <0.05 was considered statistically significant.

RESULTS

After induction, a significant decrease in CO was observed in group A (21.6% ± 4.6%) when compared with the findings in group B (11.6% ± 4.5%) and group C (9.8% ± 4.6%). The onset time of rocuronium was significantly longer in group A (177.7 ± 17.6 seconds) than in group B (121.3 ± 18.3 seconds) and group C (118.3 ± 12.3 seconds).

CONCLUSION

Rapid administration of propofol significantly delays the onset time of rocuronium by altering CO as measured with the Finometer monitor.

Pharmacodynamic Analysis of the Influence of Propofol on Left Ventricular Long-Axis Systolic Performance in Cardiac Surgical Patients

BACKGROUND

Propofol induced a decline in the left ventricular (LV) systolic performance in non-cardiac surgery. We tested the hypothesis that propofol decreased the LV contractile function by dose dependent manner in cardiac surgery patients.

METHODS

Anesthesia was maintained with target-controlled infusions of propofol and remifentanil in cardiac surgery patients. With a fixed effect-site concentration (Ce) of remifentanil (20 ng/mL) after sternotomy, the Ce of propofol was adjusted to maintain a Bispectral index of 40-60 (Ce1). Mitral annular Doppler tissue image tracings and other echocardiographic variables, including end-diastolic and end-systolic volumes, stroke volume, and mitral inflow pulse wave Doppler profile at Ce1, were recorded using transesophageal echocardiography. Echocardiographic recordings were repeated after the Ce-values of propofol were doubled and tripled at 10-minute intervals (defined as Ce2 and Ce3, respectively). Serial changes in echocardiographic variables for each Ce of propofol were assessed using generalized linear mixed effect modeling. The pharmacodynamic relationship between the Ce of propofol and peak systolic mitral annular velocity (Sm) was analyzed by logistic regression using non-linear mixed effect modeling (NONMEM).

RESULTS

Means of Ce1, Ce2, and Ce3 were 0.8, 1.6, and 2.4 μg/mL, respectively, and their means of Sm (95% confidence interval) were 9.7 (9.3-10.2), 8.7 (8.2-9.1), and 7.5 cm/sec (7.0-8.0), respectively (P < 0.01). Ce values of propofol and Sm showed a significant inter-correlation and predictability (intercept, 10.8; slope-1.0 in generalized mixed linear modeling; P < 0.01). Ce values producing 10% and 20% decline of Sm with 50%-probability were 1.4 and 2.1 μ/mL, respectively.

CONCLUSION

Propofol reduces LV systolic long-axis performance in a dose-dependent manner.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01826149.

Pretreatment with glucose-insulin-potassium improves ventricular performances after coronary artery bypass surgery: a randomized controlled trial

Heart failure is the main cause of poor outcome following open heart surgery and experimental studies have demonstrated that glucose–insulin–potassium (GIK) infusion exerts cardioprotective effects by reducing myocardial ischemia–reperfusion injuries. This randomized controlled trial was designed to assess the effects of GIK on left ventricular function in moderate-to-high risk patients undergoing on-pump isolated coronary artery bypass surgery (CABGS), or combined with aortic valve replacement. The primary outcomes were the effects of GIK on two- and three-dimensional left ventricular ejection fraction (2D and 3D-LVEF), and on transmitral flow propagation velocity (Vp), that occurred between the pre- and post-CPB periods. GIK administration was associated with favorable interaction effects (p < 0.001) on 2D-LVEF, 3D-LVEF and Vp changes over the study periods. In GIK pretreated patients (N = 54), 2-D and 3D-LVEF and Vp increased slightly during surgery (mean difference [MD] + 3.5%, 95% confidence interval [95% CI] − 0.2 to 7.1%, MD + 4.0%, 95% CI 0.6–7.4%, and MD + 22.2%, 95% CI 16.0–28.4%, respectively). In contrast, in the Placebo group (N = 46), 2D-and 3D-LVEF, as well as Vp all decreased after CPB (MD − 7.5% [− 11.6 to − 3.4%], MD − 12.0% [− 15.2 to − 8.8%] and MD − 21.3% [− 25.7 to − 16.9%], respectively). In conclusion, the administration of GIK resulted in better preservation of systolic and diastolic ventricular function in the early period following weaning from CPB.

Determinants of Myocardial Strain in Experimental Chronic Myocardial Infarction

We evaluated the relationships between regional myocardial strain measured by speckle tracking echocardiography and viability, fibrosis, hypertrophy and oxygen consumption in the infarcted or remote myocardium in a pig model of chronic myocardial infarction (MI). Thirteen farm pigs with surgical occlusion of the left anterior descending coronary artery and five sham-operated pigs were studied 3 mo post-MI. Computed tomography revealed significant left ventricle remodeling. Reduced radial or circumferential strain identified areas of transmural infarction (area under the curve: 0.82 and 0.79, respectively). In the remote non-infarcted area, radial strain correlated inversely with the amount of fibrosis (r = -0.66, p = 0.04) and myocyte hypertrophy (r = -0.68, p = 0.03). Radial strain rate inversely correlated with myocardial resting oxygen consumption assessed with ¹¹C-labeled acetate positron emission tomography (r = -0.71, p = 0.006). In conclusion, myocardial strain and strain rate reflect fibrosis, hypertrophy and oxygen consumption of the remote areas after MI.

Haemodynamic changes during propofol induction in dogs: new findings and approach of monitoring

BACKGROUND

Propofol is one of the most widely used injectable anaesthetic agents in veterinary practice. Cardiovascular effects related to propofol use in dogs remain less well defined. The main objective of this study was to evaluate the haemodynamic changes during induction of general anaesthesia with propofol in healthy dogs, by a beat-to-beat continuous monitoring. All dogs were premedicated with intramuscular acepromazine (0.015 mg/kg) and methadone (0.15 mg/kg). Transthoracic echocardiography was used to measure the velocity time integral (VTI) of the left ventricular outflow tract. A syringe driver, programmed to deliver propofol 5 mg/kg over 30 s followed by a continuous infusion of 25 mg/kg/h, was used to induce and maintain anaesthesia. From the initiation of propofol administration, heart rate (HR) and mean invasive arterial blood pressure (MAP) were recorded every 5 s for 300 s, while aortic blood flow was continuously recorded and stored for 300 S. maximum cardiovascular depression was defined the lowest MAP (MAP_Tpeak) recorded during the monitored interval. VTI and VTI*HR were calculated at 0, 30, 90, 120, 150 and 300 s post administration of propofol, and at MAP_Tpeak. Haemodynamic effects of propofol in relation to plasma and biophase concentrations were also evaluated by pharmacokinetics simulation.

RESULTS

The median (range) HR was significantly higher (p = 0.006) at the moment of maximum hemodynamic depression (Tpeak) [105(70-148) bpm] compared with pre-induction values (T0) [65(50-120) bpm]. The median (range) MAP was significantly lower (p < 0.001) at Tpeak [61(51-69) mmHg] compared with T0 [88(72-97) mmHg]. The median (range) VTI and VTI*HR were similar at the two time points [11.9(8.1-17.3) vs 13,3(9,4-16,5) cm, and 1172(806-1554) vs 1002(630-1159) cm*bpm, respectively].

CONCLUSIONS

Induction of anaesthesia with propofol causes a drop of arterial pressure in healthy dogs, however cardiac output is well maintained by compensatory chronotropic response. The magnitude of MAP_Tpeak may be strictly related with propofol plasma concentration.

Isoflurane's Effect on Intraoperative Systolic Left Ventricular Performance in Cardiac Valve Surgery Patients

BACKGROUND

Isoflurane, a common anesthetic for cardiac surgery, reduced myocardial contractility in many experimental studies, few studies have determined isoflurane's direct impact on the left ventricular (LV) contractile function during cardiac surgery. We determined whether isoflurane dose-dependently reduces the peak systolic velocity of the lateral mitral annulus in tissue Doppler imaging (S') in patients undergoing cardiac surgery.

METHODS

During isoflurane-supplemented remifentanil-based anesthesia for patients undergoing cardiac surgery with preoperative LV ejection fraction greater than 50% (n = 20), we analyzed the changes of S' at each isoflurane dose increment (1.0, 1.5, and 2.0 minimum alveolar concentration [MAC]: T1, T2, and T3, respectively) with a fixed remifentanil dosage (1.0 μg/min/kg) by using transesophageal echocardiography.

RESULTS

Mean S' values (95% confidence interval [CI]) at T1, T2, and T3 were 10.5 (8.8-12.2), 9.5 (8.3-10.8), and 8.4 (7.3-9.5) cm/s, respectively (P < 0.001 in multivariate analysis of variance test). Their mean differences at T1 vs. T2, T2 vs. T3, and T1 vs. T3 were -1.0 (-1.6, -0.3), -1.1 (-1.7, -0.6), and -2.1 (-3.1, -1.1) cm/s, respectively. Phenylephrine infusion rates were significantly increased (0.26, 0.22, and 0.47 μg/kg/min at T1, T2, and T3, respectively, P < 0.001).

CONCLUSION

Isoflurane increments (1.0-2.0 MAC) dose-dependently reduced LV systolic long-axis performance during cardiac surgeries with a preserved preoperative systolic function.

A randomized clinical trial comparing hemodynamic responses to ketamine-propofol combination (ketofol) versus etomidate during anesthesia induction in patients with left ventricular dysfunction undergoing coronary artery bypass graft surgery

INTRODUCTION

Anesthesia induction is often accompanied by a period of hemodynamic instability, which could be a significant problem in patients with compromised ventricular function. The aim of this study is to compare the hemodynamic responses to etomidate versus a combination of ketamine and propofol (ketofol) for anesthetic induction in patients with left ventricular dysfunction undergoing coronary artery bypass graft (CABG) surgery.

MATERIAL AND METHODS

In a double-blind randomized clinical study, a total of 84 patients with ischemic left ventricular dysfunction (EF < 40%) were randomly assigned to two groups (A and B). Patients in group A received etomidate 0.2 mg/kg and a placebo (normal saline); group B received a combination of ketamine (1 mg/kg) and propofol (1.5 mg/kg) at the induction of anesthesia. Two minutes after induction, hemodynamic variables, including systolic, diastolic, mean arterial pressure (SAP, DAP, MAP) and heart rate (HR), were measured immediately before and after the laryngoscopy, and before intubation and post-intubation at 1, 2, and 3 min.

RESULTS

The decrease in all hemodynamic parameters (SBP, DBP, MAP and HR) from induction time to laryngoscopy was greater in the ketofol group (group B) than in the etomidate group (group A) (p < 0.05). The ephedrine prescription rate due to hemodynamic changes was 24.4% (10 patients) and 5% (2 patients) in group B and group A, respectively (p = 0.03).

CONCLUSIONS

We found that etomidate provides superior hemodynamic stability as compared to ketofol in patients with left ventricular dysfunction undergoing CABG surgery under general anesthesia.

Continuous, Real-Time, Noninvasive Hemodynamic Cardiac Doppler Monitoring With a Novel Hands-Free Device: A Feasibility Study Compared to Standard Echo

This study sought to determine the feasibility of using noninvasive cardiac hemodynamics (NICHE), a new noninvasive Doppler-based device, to monitor real-time, simultaneous tissue and blood-flow Doppler measurements in a clinical setting, and to obtain preliminary performance data compared to a commercially available system. Doppler-based measurements have been shown to correlate well with invasive hemodynamic data and diastolic function, but their use in clinical applications has been limited by various technical issues. The NICHE device was developed to obtain simultaneous tissue and blood-flow Doppler measurements automatically, in real-time and in a hands-free manner. Thirty participants (ten normal volunteers and 20 patients in a cardiac rehab program) underwent standard echocardiographic/Doppler studies followed immediately by NICHE monitoring. Early diastolic transmitral blood-flow velocity (E) and tissue Doppler myocardial wall velocity during early relaxation (E′) were acquired using a standard echo device; and E/E′ was derived post hoc. NICHE measurements included E, E′, and directly measured instantaneous E/E′. NICHE was successfully used in 28 participants. Measurements of ENICHE ranged from 40 cm/s to over 120 cm/s and correlated well with Eecho (R = 0.93). ENICHE′ ranged from 2 to 23 cm/s and correlated well with the averaged Eecho′ (R = 0.91). Directly measured E/ENICHE′ ratios ranged from 3 to 23 and correlated well with derived E/Eecho′ (R = 0.91). The NICHE device can monitor patients in a hands-free manner and can supply real-time Doppler derived measurements of hemodynamic parameters and diastolic function that correlate well with measurements from standard echo devices.

Ketamine/propofol admixture (ketofol) at induction in the critically ill against etomidate (KEEP PACE trial): study protocol for a randomized controlled trial

BACKGROUND

Endotracheal intubation (ETI) is commonly performed as a life-saving procedure in the intensive care unit (ICU). It is often associated with significant hemodynamic perturbations and can severely impact the outcome of ICU patients. Etomidate is often chosen by many critical care providers for the patients who are hypotensive because of its superior hemodynamic profile compared to other induction medications. However, recent evidence has raised concerns about the increased incidence of adrenal insufficiency and mortality associated with etomidate use. A combination of ketamine and propofol (known as ketofol) has been studied in various settings as an alternative induction agent. In recent years, studies have shown that this combination may provide adequate sedation while maintaining hemodynamic stability, based on the balancing of the hemodynamic effects of these two individual agents. We hypothesized that ketofol may offer a valuable alternative to etomidate in critically ill patients with or without hemodynamic instability.

METHODS/DESIGN

A randomized controlled parallel-group clinical trial of adult critically ill patients admitted to either a medical or surgical ICU at Mayo Clinic in Rochester, MN will be conducted. As part of planned emergency research, informed consent will be waived after appropriate community consultation and notification. Patients undergoing urgent or emergent ETI will receive either etomidate or a 1:1 admixture of ketamine and propofol (ketofol). The primary outcome will be hemodynamic instability during the first 15 minutes following drug administration. Secondary outcomes will include ICU length of stay, mortality, adrenal function, ventilator-free days and vasoactive medication use, among others. The planned sample size is 160 total patients.

DISCUSSION

The overall goal of this trial is to assess the hemodynamic consequences of a ketamine-propofol combination used in critically ill patients undergoing urgent or emergent ETI compared to etomidate, a medication with an established hemodynamic profile. The trial will address a crucial gap in the literature regarding the optimal induction agent for ETI in patients that may have potential or established hemodynamic instability. Greater experience with planned emergency research will, hopefully, pave the way for future prospective randomized clinical trials in the critically ill population.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT02105415. 31 March 2014.

Comparison of the impact of the anesthesia induction using thiopental and propofol on cardiac function for non-cardiac surgery

Background

Thiopental and propofol have been widely used for general anesthesia induction, but their impacts on cardiac function have not been well described. A recent study speculated that anesthesia induction using propofol 2 mg/kg transiently reduced left ventricular (LV) contraction by analyzing tissue Doppler-derived imaging (TDI) during induction phase. The purpose of this study was to analyze and to compare the impacts of propofol- and thiopental-induction on LV function.

Methods

Twenty-four female patients with normal LV function undergoing non-cardiac surgery were randomly administered intravenous bolus thiopental (5 mg/kg, Thiopental-group, n = 12) or propofol (2 mg/kg, Propofol-group, n = 12) for anesthesia-induction. TDI of septal mitral annular velocity during systole (S'), early diastole (e') and atrial contraction (a') were determined by transthoracic echocardiography before and 1, 3, and 5 minutes after thiopental/propofol administration (T0, T1, T2, and T3, respectively).

Results

The bispectral index and systolic blood pressure declined significantly during anesthesia induction in both groups, however, more depressed in Thiopental-group compared with those in Propofol-group at T2 and T3 (all, p < 0.05). Among TDI two parameters demonstrated a significant inter-group difference: the S' in propofol was lower than that in Thiopental-group at T3 (p = 0.002), and a' velocities were persistently lower in Propofol-group, compared with same time values in Thiopental-group (T1, T2, and T3: p = 0.025, 0.007, and 0.009, respectively).

Conclusion

Anesthesia induction using propofol revealed a more persistent and profound decline of LV and atrial contraction than that using thiopental. Further studies are needed to understand the clinical implication.