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Evaluation of Esmolol in Controlling Increases in Heart Rate and Blood Pressure during Endotracheal Intubation in Patients Undergoing Carotid Endarterectomy
Abstract
We examined the effect of esmolol on hemodynamics during endotracheal intubation in patients with carotid artery disease. Esmolol (methyl 3-4-[2-hydroxy-3-(isopropylamino) propoxy-phenyl] propionate hyrochloride) is a water-soluble, cardioselective beta-adrenergic blocker of rapid onset and ultrashort duration of action with a half-life of 9 min. It is an ester and is rapidly metabolized by esterases in the blood to a free acid metabolite that has a beta-adrenergic blocking potency that is 1/1,600 of esmolol and methanol. Esmolol significantly blunted the maximum increases in heart rate and BP from baseline when compared with placebo during the stimulus of endotracheal intubation (P < 0.01). The average maximum heart rate increase in the placebo group was 24 beats/min and only 9 beats/min in the esmolol-treated group. The average maximum systolic BP increase in the placebo group was 45 mmHg, while an average increase of 2 mmHg was observed in the esmolol group. A significantly higher number of patients receiving placebo experienced heart rates ≥ 100 beats/min alone or in combination with systolic BP ≥ 180 mmHg.
... Various workers have used esmolol either as a bolus or as an infusion for attenuation of pressor response. Previous studies have shown that unique pharmacokinetic behaviour of esmolol makes it well suited for controlling the cardiovascular response to tracheal intubation when using a continuous infusion technique 37,38 reported that esmolol bolus followed by infusion to be useful for preventing the haemodynamic response to suspension laryngoscopy. But the limitation of response was its effectiveness against only increase in heart rate but not blood pressure or Q TC interval. ...
... But the limitation of response was its effectiveness against only increase in heart rate but not blood pressure or Q TC interval. Cucchiara et al. 38 reported an effective blunting of the increases in heart rate and arterial blood pressure with a continuous infusion of esmolol for 12 minutes before intubation (500 mg/kg/min for 4 minutes followed by 300 g/kg/min for 8 minutes) in a group of patients undergoing carotid endarterectomy. Figueredo and Gercia-Fuentes 47 showed that the effective regimen was a loading dose of 500 mg/kg/min over 4 min followed by continuous infusion dose of 200-300 mg/kg/min. ...
... Esmolol'ün trakeal entübasyona bağlı hemodinamik yanıtı baskılaması ile ilgili çeşitli çalışmalar yapılmıştır. [8][9][10][11] Metoprolol ise esmololde olduğu gibi hızlı etki başlangıçlı olmakla birlikte etki süresi daha uzun olan (orta etki süreli), kardiyoselektif betablokördür. Ancak metoprolol'ün hemodinamik yanıtı baskılaması ile ilgili çok az çalışma vardır. ...
... boyunca ve 0.3 mg kg -1 dk -1 8 dk. boyunca uyguladıkları esmolol'ü plasebo ile karşılaştırmışlardır. 9 Maksi-Tablo 2. Grupların çalışma süresince değişik zamanlarda ölçülen sistolik arter basıncı (SAB), diyastolik arter basıncı (DAB), ortalama arter basıncı (OAB) ve kalp atım hızı (KAH) değerleri (Ort±SD) (Her grup 25 olgudan oluşmaktadır). Menkhaus ve ark.nın anestezi altındaki hastalarda esmololun kardiyovasküler etkileri ile ilgili yaptıkları çalışmalarında hastalar dört gruba ayrılmış, esmolol Grup 1'e 500 µg kg -1 dk -1 1 dk içinde sonra 100 µg kg -1 dk -1 6 dk boyunca infüze edilmiş, Grup 2'ye 500 µg kg -1 dk -1 2 dk. ...
... Since intubation-induced hemodynamic changes have a short duration, ultra-short duration intravenous beta-blockers, such as esmolol, are preferred 46,54 . The benefit of beta-blockers for coronary artery disease patients before tracheal intubation is also result of a myocardial depressing effect of such drugs with potential to change ventricular function. ...
... Nos pacientes que apresentam insuficiência coronariana patente ou em fase latente, para limitar as elevações da freqüência cardíaca que ocorrem durante a intubação traqueal, na recuperação anestésica ou no per-operatório. Nessa última situação, é importante que a profundidade anestésica esteja de acordo com a intensidade de estímulo cirúrgico.Como as alterações hemodinâmicas induzidas pela intubação são de curta duração, a preferência é pelo uso de beta-bloqueador de ultracurta duração, por via venosa, como o esmolol46,54 . No paciente coronariopata, o benefício da utilização de beta-bloqueadores, utilizados antes da intubação traqueal, é também resultado do efeito depressor do miocárdio dessas drogas, com potencial para alterar a função ventricular. ...
JUSTIFICATIVA E OBJETIVOS: Informações experimentais e clínicas têm sugerido que os b-bloqueadores apresentam efeitos hemodinâmicos importantes e protetores durante o ato anestésico-cirúrgico. O objetivo deste trabalho é revisar as informações farmacológicas e clínicas dos b-bloqueadores para sua utilização adequada na medicina per-operatória. CONTEÚDO: Os b-bloqueadores seletivos inibem preferencialmente os b1-receptores reduzindo a freqüência e inotropismo cardíacos e determinando redução no consumo de oxigênio do miocárdio. Os b-bloqueadores não seletivos inibem também os b2-receptores, aumentando a resistência bronquiolar e vascular periférica. Alguns b-bloqueadores são, também, vasodilatadores. O tratamento prolongado com os b-bloqueadores aumenta a densidade dos b-receptores na membrana celular, o que pode explicar a hiperatividade simpática que pode ocorrer durante a parada do tratamento desses medicamentos. Em cirurgia não cardíaca, os efeitos benéficos do b-bloqueadores em pacientes hipertensos ou nos que apresentam doença coronariana têm sido demonstrados, com redução da incidência de isquemia miocárdica no pós-operatório e da mortalidade durante o período de dois anos que se segue à operação. CONCLUSÕES: O tratamento com b-bloqueadores deve ser mantido até o período da manhã da operação, exceto nos pacientes com sinais de intolerância à droga, como hipotensão ou bradicardia importante. Os b-bloqueadores exercem efeito benéfico na recuperação pós-operatória de pacientes com doenças cardiovasculares ou nos que apresentam fatores de risco. Por isso, o emprego desses medicamentos é importante na medicina per-operatória e deve ser ampliado.
... As both these procedures are key during general anesthesia, the hemodynamic responses that occur during the procedure must be alleviated to avoid untoward deleterious effects for the safe conduct of anaesthesia. Many different drugs and techniques have been used in previous studies with varying degrees of success to alleviate the cardiovascular response during these procedures [4][5][6][7][8]. ...
Introduction:
Hemodynamic changes during laryngoscopy and tracheal intubation must be reduced for safe and effective anesthesia. The present study was conducted to compare the efficacy of oral clonidine, gabapentin and placebo in alleviating the hemodynamic changes due to tracheal intubation and laryngoscopy.
Methods:
This was a double-blinded randomized controlled trial conducted on 90 patients who were undergoing elective surgery and were randomized into three groups. Group I (n=30) received a placebo, group II (n=30) received gabapentin and group III (n=30) received clonidine as premedication before anesthesia induction. Patient heart rate and pressor response were recorded periodically and compared between the groups.
Results:
There was no significant difference in the baseline heart rate (HR) and mean arterial pressure (MAP) between the groups. HR elevation was observed in all three groups and found to be significant (p=0.0001) but the increase was higher in the placebo (15 min: 80.80± 15.41) and lower in the clonidine group (15 min: 65.53± 12.43). The elevation in systolic and diastolic blood pressure was least and transient in the gabapentin group, as compared to placebo and clonidine group. Intra-operatively, the requirement of opioids was higher in the placebo as compared to clonidine and gabapentin (p < .001).
Conclusion:
Clonidine and gabapentin were effective in reducing the hemodynamic changes during laryngoscopy and intubation.
... So usage appropriate dose of esmolol is necessary to avoid the side effects of the drugs and to achieve adequate hemodynamic stability. [10][11][12][13] Studies done by Gupta et al 14 proved that Inj.Esmolol is better than inj.fentanyl in attenuating the pressor response of laryngoscopy and intubation.Many studies have proven that Esmolol is better than IVlignocaine in attenuating the laryngoscopy response.Mulimani et al 15 has proven that Inj.Esmolol given before 2 min of intubation have good response in attenuating the laryngoscopy response.so in our study we have given Esmolol bolus dose 2 min before the intubation. ...
Background: General anaesthesia is an altered physiological state characterized by reversible loss of consciousness, amnesia ,analgesia and some degree of muscle relaxation.no single agents can produce these desired effects.It involves inhalational anaesthetics,induction agents, opioids, neuromuscular blockers. Combination of all these drugs will produce the optimal anaesthesia which is known as balanced anaesthesia. Airway management is an integral part of general anaesthesia, which includes direct laryngoscopy and endotracheal intubation. Objective: To compare the efficacy of two different doses of esmolol to attenuate the hemodynamic response during laryngoscopy and endotracheal intubation. Methodology: The present comparative cross sectional study was conducted by the Department of Anaesthesia at Vinayaka Missions KirupanandaVariyar Medical College and Hospital, Salem from December 2019 – May 2021. The comparative study was done between two study groups with Group A receiving 50 mg of IV Esmolol and Group B Receiving 100 mg of IV Esmolol, A total of 60 study patients who met the inclusion criteria were included in the Study and divided into 30 subjects in each group. Results: The mean age of the patients in Group A was 37.3 (12.0) years with a minimum of 18 years and a maximum of 60 years.
... During the induction period particularly at intubation esmolol, an ultra-short acting beta blocker with relative cardioselectivity may be preferred to propranolol which has a longer duration of action. Beta blockers are effective in blunting both hypertensive and tachycardic responses to stressful stimuli such as laryngoscopy [16]. ...
... beta blocker 9 , calcium channel blocker 10 , gabapentin, pregabalin, alpha 2 agonists 11,12,13 as clonidine and dexmedetomidine, opioids as alfentanyl 14 , fentanyl 15 , remifentanyl 16 have traditionally been used as preoperative medication to eliminate or to suppress the stress response to laryngoscopy and intubation. Clonidine is an alpha 2 adrenergic agonist, stimulates alpha 2A subtype of alpha 2 adrenergic receptors in the brain stem resulting in a reduction in sympathetic outflow from central nervous system thus causing lowering of arterial pressure by an effect on both cardiac output and peripheral resistance. ...
p> Background and Aims: We conducted a prospective, randomized, double-blind and controlled trial to compare the effects of oral clonidine and gabapentin as premedication in obtunding hemodynamic response to laryngoscopy and intubation in normotensive patients undergoing elective surgery. We also compared the preoperative anxiety and sedation status between these two drugs.
Materials and Methods: A total of 60 patients of American Society of Anesthesiologists (ASA) physical status I, aged 20 -50 years of either sex enrolled in the study were randomly divided into two groups of 30 each. Group A patients received oral clonidine 200 mcg and Group B patients received oral gabapentin 900 mg, 90 minutes prior to induction of anesthesia. The heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure were observed and recorded pre and post endotracheal intubation. Anxiety and sedation score were noted after 60 minutes of oral administration of drug as well as before induction of anesthesia.
Results: Both groups were matched for age, sex, weight and intubation time. Anxiety score and sedation score before induction were significantly better in clonidine group as compared with gabapentin group. Also oral clonidine attenuated the increase in heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure better than oral gabapentin (p<0.05).
Conclusion: Oral clonidine provided good attenuation of hemodynamic response to laryngoscopy and intubation as compared with oral gabapentin. Also clonidine is better agent as anxiolytic and sedative than gabapentin.
Anwer Khan Modern Medical College Journal Vol. 9, No. 2: Jul 2018, P 131-136</p
... Study drug esmolol 1 mg/kg and lidocaine 1.5 mg/kg of 10 mL volume were given intravenously during preoxygenation. 11,12 After 5 minutes of intubation, again the blood sample for cortisol was collected. At the same time, pulse rate, diastolic blood pressure, systolic blood pressure and SPO2 were noted. ...
... Indeed, comparative effectiveness studies in anesthetized patients have demonstrated that bolus injections of 20 -200 mg of esmolol attenuate HR responses to laryngoscopy and endotracheal intubation (13,14,29,33,41,43). Esmolol can also be administered as a continuous infusion to treat intraoperative tachycardia due to airway or surgical stimulation (10,16,18,31,61), as part of the hemodynamic management during resection of pheochromocytomas (40,62), to control HR during acute coronary syndromes (3) and thyrotoxicosis (8,12), and to aid in the diagnosis of supraventricular tachycardia (34). Studies in healthy volunteers conducted in the 1980s and 1990s demonstrated that esmolol infusion is effective (vs. ...
... b-blocker esmolol is good because its cardioselective b 1 receptor blocking action is of short duration. 9 Its elimination half life is about 9 minutes. ...
The present study was done on 100 patients undergoing various elective surgical procedures to compare the efficacy of IV esmolol, diltiazem and magnesium sulphate for attenuating the haemodynamic response to laryngoscopy and tracheal intubation. It was found that esmolol proved to be most effective in attenuating rise in heart rate following laryngoscopy and intubation while the rise in blood pressure was suppressed but not prevented by bolus dose of esmolol (2 mgkg -1 .) Keywords : Esmolol, Diltiazem, Magnesium sulphate, Haemodynamic response, Laryngoscopy and tracheal intubation.
... Vasodilators such as nitroprusside,[7] hydralazine[8] and nitroglycerine[9] have been used to attenuate these hemodynamic responses with varying degree of success. Calcium channel blocker,[10] beta blockers[1112] and opioids such as alfentanil,[13] fentanyl[14] and remifentanil[15] have also been used in different dosage regimens to attenuate hemodynamic response to laryngoscopy and intubation. ...
Background:
We compared the effects of oral clonidine and gabapentin as premedicant in obtunding hemodynamic response to laryngoscopy and intubation in normotensive patients undergoing elective surgery.
Methods:
A total of 100 patients of either sex enrolled in the study were randomly divided into two groups of 50 each. Group A patients received oral clonidine 200 μg and Group B patients received oral gabapentin 900 mg, 90 min prior to induction of anesthesia.
Results:
Both groups were matched for age, sex weight and intubation time. Anxiety score and sedation scores before induction were significantly better in Group A as compared with Group B. Heart rate rise was obtunded in Group A except at 1 min, as compared with Group B in which tachycardia persisted even at 3 and 5 min following intubation. Mean arterial pressure was maintained below baseline at all times in Group A as compared with Group B in which significant rise (+7.55%, P < 0.001) was seen at 1 min after intubation.
Conclusion:
Oral clonidine provided good attenuation of hemodynamic response to laryngoscopy and intubation as compared with oral gabapentin.
The previous discussion has indicated that labetalol possesses unique properties that isolate it from categorization with other antihypertensive drugs. By adding this drug to the armamentarium of the anesthesiologist, he or she can more effectively treat a wider range and variety of cases of hypertension without impacting on other physiologic parameters, thus optimizing more patients’ care.
Background
The limited applicability of evidence from RCTs in real-word practice is considered a potential bottleneck for evidence-based practice but rarely systematically assessed. Using our failure to recruit patients into a perioperative beta-blocker trial, we set out to analyse the restrictiveness and generalisability of trial eligibility criteria in a real-world cohort.
Methods
We prospectively included adult patients (≥18 yr) scheduled for elective noncardiac surgery at an academic tertiary care facility who were screened for inclusion in a planned perioperative beta-blocker RCT, which was terminated owing to recruitment failure. The primary outcome was the proportion of screened patients who matched the eligibility criteria of 36 published RCTs included in a large Cochrane meta-analysis on perioperative beta-blocker therapy. The pragmatic/explanatory level of each RCT was assessed using the PRagmatic–Explanatory Continuum Indicator Summary 2 (PRECIS-2) score, which ranges from 9 points (indicating a very explanatory study) to 45 points (indicating a very pragmatic study).
Results
A total of 2241 patients (54% female, n=1215; 52 [standard deviation, 20] yr) were included for the assessment of trial eligibility between October 2015 and January 2016. Only a small proportion of patients matched the inclusion and exclusion criteria for each of the 36 RCTs, ranging from 53% to 0%. The average proportion of patients who did match the eligibility criteria of all 36 RCTs was 6.5% (n=145; 95% confidence interval, 6.3–6.6). A higher PRECIS-2 score was associated with a higher proportion of matching patients (P<0.001).
Conclusions
Trial eligibility criteria in perioperative beta-blocker therapy trials are overly restrictive and not generalisable to a real-world surgical population.
Clinical trial registration
EudraCT#: 2015-002366-23.
Background:
Randomized controlled trials (RCTs) have yielded conflicting results regarding the ability of beta-blockers to influence perioperative cardiovascular morbidity and mortality. Thus routine prescription of these drugs in an unselected population remains a controversial issue. A previous version of this review assessing the effectiveness of perioperative beta-blockers in cardiac and non-cardiac surgery was last published in 2018. The previous review has now been split into two reviews according to type of surgery. This is an update, and assesses the evidence in non-cardiac surgery only.
Objectives:
To assess the effectiveness of perioperatively administered beta-blockers for the prevention of surgery-related mortality and morbidity in adults undergoing non-cardiac surgery.
Search methods:
We searched CENTRAL, MEDLINE, Embase, CINAHL, Biosis Previews and Conference Proceedings Citation Index-Science on 28 June 2019. We searched clinical trials registers and grey literature, and conducted backward- and forward-citation searching of relevant articles.
Selection criteria:
We included RCTs and quasi-randomized studies comparing beta-blockers with a control (placebo or standard care) administered during the perioperative period to adults undergoing non-cardiac surgery. If studies included surgery with different types of anaesthesia, we included them if 70% participants, or at least 100 participants, received general anaesthesia. We excluded studies in which all participants in the standard care control group were given a pharmacological agent that was not given to participants in the intervention group, studies in which all participants in the control group were given a beta-blocker, and studies in which beta-blockers were given with an additional agent (e.g. magnesium). We excluded studies that did not measure or report review outcomes.
Data collection and analysis:
Two review authors independently assessed studies for inclusion, extracted data, and assessed risks of bias. We assessed the certainty of evidence with GRADE.
Main results:
We included 83 RCTs with 14,967 participants; we found no quasi-randomized studies. All participants were undergoing non-cardiac surgery, and types of surgery ranged from low to high risk. Types of beta-blockers were: propranolol, metoprolol, esmolol, landiolol, nadolol, atenolol, labetalol, oxprenolol, and pindolol. In nine studies, beta-blockers were titrated according to heart rate or blood pressure. Duration of administration varied between studies, as did the time at which drugs were administered; in most studies, it was intraoperatively, but in 18 studies it was before surgery, in six postoperatively, one multi-arm study included groups of different timings, and one study did not report timing of drug administration. Overall, we found that more than half of the studies did not sufficiently report methods used for randomization. All studies in which the control was standard care were at high risk of performance bias because of the open-label study design. Only two studies were prospectively registered with clinical trials registers, which limited the assessment of reporting bias. In six studies, participants in the control group were given beta-blockers as rescue therapy during the study period.The evidence for all-cause mortality at 30 days was uncertain; based on the risk of death in the control group of 25 per 1000, the effect with beta-blockers was between two fewer and 13 more per 1000 (risk ratio (RR) 1.17, 95% confidence interval (CI) 0.89 to 1.54; 16 studies, 11,446 participants; low-certainty evidence). Beta-blockers may reduce the incidence of myocardial infarction by 13 fewer incidences per 1000 (RR 0.72, 95% CI 0.60 to 0.87; 12 studies, 10,520 participants; low-certainty evidence). We found no evidence of a difference in cerebrovascular events (RR 1.65, 95% CI 0.97 to 2.81; 6 studies, 9460 participants; low-certainty evidence), or in ventricular arrhythmias (RR 0.72, 95% CI 0.35 to 1.47; 5 studies, 476 participants; very low-certainty evidence). Beta-blockers may reduce atrial fibrillation or flutter by 26 fewer incidences per 1000 (RR 0.41, 95% CI 0.21 to 0.79; 9 studies, 9080 participants; low-certainty evidence). However, beta-blockers may increase bradycardia by 55 more incidences per 1000 (RR 2.49, 95% CI 1.74 to 3.56; 49 studies, 12,239 participants; low-certainty evidence), and hypotension by 44 more per 1000 (RR 1.40, 95% CI 1.29 to 1.51; 49 studies, 12,304 participants; moderate-certainty evidence).We downgraded the certainty of the evidence owing to study limitations; some studies had high risks of bias, and the effects were sometimes altered when we excluded studies with a standard care control group (including only placebo-controlled trials showed an increase in early mortality and cerebrovascular events with beta-blockers). We also downgraded for inconsistency; one large, well-conducted, international study found a reduction in myocardial infarction, and an increase in cerebrovascular events and all-cause mortality, when beta-blockers were used, but other studies showed no evidence of a difference. We could not explain the reason for the inconsistency in the evidence for ventricular arrhythmias, and we also downgraded this outcome for imprecision because we found few studies with few participants.
Authors' conclusions:
The evidence for early all-cause mortality with perioperative beta-blockers was uncertain. We found no evidence of a difference in cerebrovascular events or ventricular arrhythmias, and the certainty of the evidence for these outcomes was low and very low. We found low-certainty evidence that beta-blockers may reduce atrial fibrillation and myocardial infarctions. However, beta-blockers may increase bradycardia (low-certainty evidence) and probably increase hypotension (moderate-certainty evidence). Further evidence from large placebo-controlled trials is likely to increase the certainty of these findings, and we recommend the assessment of impact on quality of life. We found 18 studies awaiting classification; inclusion of these studies in future updates may also increase the certainty of the evidence.
Context:
Laryngoscopy and endotracheal intubation result in an increase in heart rate and blood pressure; they evoke life-threatening complications. The esmolol is short-acting cardioselective beta-blocker and brings advantages to the perioperative management of tachycardia and hypertension.
Aims:
The aim of this study was to compare the efficacy of a bolus dose of esmolol and bolus dose of lignocaine for attenuation of the pressor response to laryngoscopy and intubation.
Settings and design:
Sixty patients of both sex, aged 20-50 years, belonging to the American Society of Anesthesiologists physical Status I and II randomly allocated into two groups (n = 30).
Materials and methods:
The study drugs diluted in 10-ml normal saline. Group I received esmolol 1.5 mg/kg and Group II received lignocaine 1.5 mg/kg 2 min before inducing the patients with thiopentone 5 mg/kg and suxamethonium 1.5 mg/kg. The heart rate, systolic blood pressure, and diastolic blood pressure were measured at basal, during intubation, and 1, 2, 3, and 5 min after intubation, and based on these values, the mean arterial pressure (MAP) and rate pressure product (RPP) was calculated.
Statistical analysis used:
The Student's t-test and data were represented by mean standard deviation and graphs.
Results:
The mean pulse rate, mean of MAP, and mean of RPP at intubation and at 1, 2, 3, and 5 min after intubation in lignocaine group showed a significant rise in these values but in esmolol group it remained nearer to or less than baseline values.
Conclusions:
Esmolol 1.5 mg/kg is effective in attenuating the pressor response in comparison with lignocaine 1.5 mg/kg during laryngoscopy and intubation.
Background:
Randomized controlled trials have yielded conflicting results regarding the ability of beta-blockers to influence perioperative cardiovascular morbidity and mortality. Thus routine prescription of these drugs in unselected patients remains a controversial issue.
Objectives:
The objective of this review was to systematically analyse the effects of perioperatively administered beta-blockers for prevention of surgery-related mortality and morbidity in patients undergoing any type of surgery while under general anaesthesia.
Search methods:
We identified trials by searching the following databases from the date of their inception until June 2013: MEDLINE, Embase , the Cochrane Central Register of Controlled Trials (CENTRAL), Biosis Previews, CAB Abstracts, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Derwent Drug File, Science Citation Index Expanded, Life Sciences Collection, Global Health and PASCAL. In addition, we searched online resources to identify grey literature.
Selection criteria:
We included randomized controlled trials if participants were randomly assigned to a beta-blocker group or a control group (standard care or placebo). Surgery (any type) had to be performed with all or at least a significant proportion of participants under general anaesthesia.
Data collection and analysis:
Two review authors independently extracted data from all studies. In cases of disagreement, we reassessed the respective studies to reach consensus. We computed summary estimates in the absence of significant clinical heterogeneity. Risk ratios (RRs) were used for dichotomous outcomes, and mean differences (MDs) were used for continuous outcomes. We performed subgroup analyses for various potential effect modifiers.
Main results:
We included 88 randomized controlled trials with 19,161 participants. Six studies (7%) met the highest methodological quality criteria (studies with overall low risk of bias: adequate sequence generation, adequate allocation concealment, double/triple-blinded design with a placebo group, intention-to-treat analysis), whereas in the remaining trials, some form of bias was present or could not be definitively excluded (studies with overall unclear or high risk of bias). Outcomes were evaluated separately for cardiac and non-cardiac surgery.CARDIAC SURGERY (53 trials)We found no clear evidence of an effect of beta-blockers on the following outcomes.• All-cause mortality: RR 0.73, 95% CI 0.35 to 1.52, 3783 participants, moderate quality evidence.• Acute myocardial infarction (AMI): RR 1.04, 95% CI 0.71 to 1.51, 3553 participants, moderate quality evidence.• Myocardial ischaemia: RR 0.51, 95% CI 0.25 to 1.05, 166 participants, low quality evidence.• Cerebrovascular events: RR 1.52, 95% CI 0.58 to 4.02, 1400 participants, low quality evidence.• Hypotension: RR 1.54, 95% CI 0.67 to 3.51, 558 participants, low quality evidence.• Bradycardia: RR 1.61, 95% CI 0.97 to 2.66, 660 participants, low quality evidence.• Congestive heart failure: RR 0.22, 95% CI 0.04 to 1.34, 311 participants, low quality evidence.Beta-blockers significantly reduced the occurrence of the following endpoints.• Ventricular arrhythmias: RR 0.37, 95% CI 0.24 to 0.58, number needed to treat for an additional beneficial outcome (NNTB) 29, 2292 participants, moderate quality evidence.• Supraventricular arrhythmias: RR 0.44, 95% CI 0.36 to 0.53, NNTB five, 6420 participants, high quality evidence.• On average, beta-blockers reduced length of hospital stay by 0.54 days (95% CI -0.90 to -0.19, 2450 participants, low quality evidence).NON-CARDIAC SURGERY (35 trials)Beta-blockers significantly increased the occurrence of the following adverse events.• All-cause mortality: RR 1.25, 95% CI 1.00 to 1.57, 11,413 participants, low quality of evidence, number needed to treat for an additional harmful outcome (NNTH) 167.• Hypotension: RR 1.50, 95% CI 1.38 to 1.64, NNTH 16, 10,947 participants, high quality evidence.• Bradycardia: RR 2.23, 95% CI 1.48 to 3.36, NNTH 21, 11,033 participants, moderate quality evidence.We found a potential increase in the occurrence of the following outcomes with the use of beta-blockers.• Cerebrovascular events: RR 1.59, 95% CI 0.93 to 2.71, 9150 participants, low quality evidence.Whereas no clear evidence of an effect was found when all studies were analysed, restricting the meta-analysis to low risk of bias studies revealed a significant increase in cerebrovascular events with the use of beta-blockers: RR 2.09, 95% CI 1.14 to 3.82, NNTH 265, 8648 participants.Beta-blockers significantly reduced the occurrence of the following endpoints.• AMI: RR 0.73, 95% CI 0.61 to 0.87, NNTB 76, 10,958 participants, high quality evidence.• Myocardial ischaemia: RR 0.51, 95% CI 0.34 to 0.77, NNTB nine, 978 participants, moderate quality evidence.• Supraventricular arrhythmias: RR 0.73, 95% CI 0.57 to 0.94, NNTB 112, 8744 participants, high quality evidence.We found no clear evidence of an effect of beta-blockers on the following outcomes.• Ventricular arrhythmias: RR 0.68, 95% CI 0.31 to 1.49, 476 participants, moderate quality evidence.• Congestive heart failure: RR 1.18, 95% CI 0.94 to 1.48, 9173 participants, moderate quality evidence.• Length of hospital stay: mean difference -0.45 days, 95% CI -1.75 to 0.84, 551 participants, low quality evidence.
Authors' conclusions:
According to our findings, perioperative application of beta-blockers still plays a pivotal role in cardiac surgery, as they can substantially reduce the high burden of supraventricular and ventricular arrhythmias in the aftermath of surgery. Their influence on mortality, AMI, stroke, congestive heart failure, hypotension and bradycardia in this setting remains unclear.In non-cardiac surgery, evidence shows an association of beta-blockers with increased all-cause mortality. Data from low risk of bias trials further suggests an increase in stroke rate with the use of beta-blockers. As the quality of evidence is still low to moderate, more evidence is needed before a definitive conclusion can be drawn. The substantial reduction in supraventricular arrhythmias and AMI in this setting seems to be offset by the potential increase in mortality and stroke.
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 μg/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 μg/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.
Sympathomimetika sind nach wie vor unentbehrliche Medikamente der Notfallmedizin. Ziel der Behandlung bei Herz- und Kreislaufstillstand, akuter Herzinsuffizienz und bestimmten Schockformen ist die Wiederherstellung einer adäquaten Auswurfleistung des Herzens, eines ausreichenden Perfusionsdrucks oder einer Optimierung des peripheren Gefäßwiderstands. Dabei werden im Myokard vorwiegend β1-adrenerge Rezeptoren, an den Gefäßen dagegen je nach Pharmakon β2-, α1 oder dopaminerge Rezeptoren stimuliert (Abb. 1). Der therapeutische Effekt hängt außer von der Art und Dosierung des Katecholamins von der hämodyna-mischen Ausgangslage sowie von der Zahl und Ansprechbarkeit adrenerger Rezeptoren ab. Bei Erkrankungen, die mit einem hohen Sympathikotonus bzw. erhühten Katecholaminspiegeln im Plasma einhergehen, wie z. B. bei Herzinsuffizienz, konnte eine „down regulation“ der β1-Rezeptoren, d.h. eine verminderte β1 -Rezeptorendichte sowie eine abgeschwächte inotrope Ansprechbarkeit des Myokards auf exogene Katecholamine nachgewiesen werden [9, 29] (Abb. 2). Eine Dauermedikation mit Sympathomimetika (z. B. bei Patienten mit Asthma bronchiale) führt gleichfalls zu einer (selektiven) „down regulation“ β1-adrenerger Rezeptoren [32], wobei jedoch die Funktion myokardialer und vaskulärer α1-Rezeptoren erhalten bleibt [38].
In der operativen Medizin sowie in der Notfallmedizin sind Sympathomimetika nach wie vor unentbehrliche Medikamente. Ziel der Behandlung bei Herz- und Kreislaufstillstand, akuter Herzinsuffizienz und bestimmten Schockformen ist die Wiederherstellung einer adäquaten Auswurfleistung des Herzens, eines ausreichenden Perfusionsdrucks oder eine Optimierung des peripheren Gefäßwiderstandes. Dabei werden im Myokard vorwiegend ß
1-adrenerge Rezeptoren, an den Gefäßen dagegen je nach Pharmakon ß
2-, α
1- oder dopaminerge Rezeptoren stimuliert (Tabelle 1).
The prevention of myocardial ischemia should be one of the main objectives during anesthesia [1]. If we define the myocardial ischemia as the rupture of the balance between the transport of O2 (DO2) and the local metabolic needs, two different types can be identified:
absolute ischemia, following the total absence of perfusion. This situation leads to irreversible cellular alterations. All preventive actions are, in this case, impracticable;
relative ischemia, for DO2 that is inadequate but sufficient to maintain temporary cellular viability. It is a high-risk situation which must be recognized and treated very fast. The causative mechanism frequently involved is tachycardia, generally determined by an adrenergic discharge with beta-1 positive effects.
Als „perioperative kardiale Morbidität“ werden prä-, intra- oder postoperativ neu auftretende Myokardinfarkte, instabile Angina pectoris, akute Herzinsuffizienz, behandlungsbedürftige Arrhythmien und primär kardial bedingte Todesfälle zusammengefaßt. Diese Komplikationen sind heute die häufigsten Ursachen für postoperative Morbidität und Mortalität.
In neurosurgery, microsurgical techniques have led to a distinct improvement of the prognosis for intracranial, infratentorial operations. It can therefore be expected that the anesthetist will use all existing possibilities to provide the neurosurgeon with optimal conditions for operating on the patient.
Trial Protocol
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Background: Direct laryngoscopy and endotracheal intubation result in tachycardia and hypertension. This response is exaggerated in hypertensive patients who are at risk of cardiovascular or cerebrovascular events. The objective of present study was to evaluate the pressor response in controlled hypertensive patients, and compare the effects of esmolol with a combination of esmolol and fentanyl. Methodology: The study was conducted in 90 controlled hypertensive patients posted for surgery under general anesthesia. The patients were randomized into three equal groups to receive normal saline (Group C = 30 patients), esmolol 1.5 mg/kg (Group E = 30 patients) and esmolol 1.5 mg/kg with fentanyl 2 μg/kg (Group EF = 30 patients). Following study drugs anesthesia induced with thiopentone 5 mg/kg, intubated with suxamethonium 1.5 mg/kg and maintained with 66% nitrous oxide, oxygen and isoflurane 0.6-1.2 vol%. Heart rate and arterial pressure were recorded at baseline, immediately after intubation, 1, 3, 5 and 7 minutes post-intubation. Results: In all 3 groups, the rise in heart rate and blood pressure was the highest at one minute post-intubation and immediately after intubation respectively. Heart rate was significantly high in Group C compared to other groups at all time intervals and there was no difference between Groups E and EF. Blood pressure was significantly different at all time intervals between Groups C and E, between C and EF and between E and EF. 43% of patients in Group EF had significant hypotension during study period. Conclusion: Esmolol 1.5 mg/kg is effective in attenuating haemodynamic response to laryngoscopy and intubation in controlled hypertensive patients. Esmolol 1.5 mg/kg with fentanyl 2 μg/kg should be used cautiously as it causes hypotension following intubation.
CKD patients are at higher risk for mortality and adverse outcomes in the perioperative setting. Though surgical procedures in CKD patients are commonly performed, a paucity of research exists on the adequate evaluation, management and minimization of perioperative risk. Most data are tangential and explore the surgical risk of conditions that are associated with CKD, such as CVD or anemia. Some strategies that have been adopted in the management of perioperative CKD patients include avoidance of nephrotoxic medications, analysis and adjustment of electrolyte and glucose abnormalities, correction of anemia, and careful attention to types and amount of resuscitative fluids. Intraoperatively, the proper use of anesthetics, analgesics and neuromuscular blocking agents, which exhibit altered pharmacodynamics and pharmacokinetics in CKD patients, can minimize unwanted side-effects. Proper attention should be paid to postoperative planning and management, with specific attention paid to reinitiation of home medications, as well as adequate nutrition, mobilization and discharge strategies.
In a non-double-blind, prospective, randomized study, the intraoperative electrocardiograms of 128 mildly hypertensive surgical patients were examined in order to determine the incidence of myocardial ischemia during anesthesia. No patient had been receiving chronic antihypertensive therapy prior to the study, but a single small oral dose of a beat-adrenergic blocking agent (labetalol, atenolol, or oxprenolol) was given to 89 of them along with premedication-Forty-four per cent of the untreated control patients and 61% of the patients pretreated with a beat-adrenergic blocking agent had normal preoperative electroca rdiograms and no risk factors for coronary artery disease other than hypertension (this difference between groups was not statistically significant). During tracheal intubation and/or emergence from anesthesia, a brief, self-limited episode of myocardial ischemia was detected in 11 of 39 untreated control patients, and in two of 89 patients pretreated with a betaadrenergic blocking agent (P < 0.001). Tachycardia always accompanied the ischemic events, but a conspicuous increase in blood pressure did not. The authors conclude that mild hypertension, when untereated prior to the induction of anesthesia, is associated with a high incidence of myocardial ischemia; and that a single small oral dose of a beat-adrenergic blocking agent, given with premedication, can significantly reduce that risk.
Many medications have been used to prevent the hypertensive response to the induction of general anesthesia and laryngoscopy in preeclamptic patients, with varying results. In this focused review, we summarize the available data and pharmacologic profiles of these drugs. Several different drug classes may be used safely; however, magnesium bolus, lidocaine, calcium channel antagonists other than nicardipine, and hydralazine are not recommended. Further research is warranted into the hemodynamic impact of varying the induction drug dose or combining different classes of drugs.
Background:
Randomized controlled trials have yielded conflicting results regarding the ability of beta-blockers to influence perioperative cardiovascular morbidity and mortality. Thus routine prescription of these drugs in unselected patients remains a controversial issue.
Objectives:
The objective of this review was to systematically analyse the effects of perioperatively administered beta-blockers for prevention of surgery-related mortality and morbidity in patients undergoing any type of surgery while under general anaesthesia.
Search methods:
We identified trials by searching the following databases from the date of their inception until June 2013: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Biosis Previews, CAB Abstracts, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Derwent Drug File, Science Citation Index Expanded, Life Sciences Collection, Global Health and PASCAL. In addition, we searched online resources to identify grey literature.
Selection criteria:
We included randomized controlled trials if participants were randomly assigned to a beta-blocker group or a control group (standard care or placebo). Surgery (any type) had to be performed with all or at least a significant proportion of participants under general anaesthesia.
Data collection and analysis:
Two review authors independently extracted data from all studies. In cases of disagreement, we reassessed the respective studies to reach consensus. We computed summary estimates in the absence of significant clinical heterogeneity. Risk ratios (RRs) were used for dichotomous outcomes, and mean differences (MDs) were used for continuous outcomes. We performed subgroup analyses for various potential effect modifiers.
Main results:
We included 89 randomized controlled trials with 19,211 participants. Six studies (7%) met the highest methodological quality criteria (studies with overall low risk of bias: adequate sequence generation, adequate allocation concealment, double/triple-blinded design with a placebo group, intention-to-treat analysis), whereas in the remaining trials, some form of bias was present or could not be definitively excluded (studies with overall unclear or high risk of bias). Outcomes were evaluated separately for cardiac and non-cardiac surgery. CARDIAC SURGERY (53 trials)We found no clear evidence of an effect of beta-blockers on the following outcomes.• All-cause mortality: RR 0.73, 95% CI 0.35 to 1.52, 3783 participants, moderate quality of evidence.• Acute myocardial infarction (AMI): RR 1.04, 95% CI 0.71 to 1.51, 3553 participants, moderate quality of evidence.• Myocardial ischaemia: RR 0.51, 95% CI 0.25 to 1.05, 166 participants, low quality of evidence.• Cerebrovascular events: RR 1.52, 95% CI 0.58 to 4.02, 1400 participants, low quality of evidence.• Hypotension: RR 1.54, 95% CI 0.67 to 3.51, 558 participants, low quality of evidence.• Bradycardia: RR 1.61, 95% CI 0.97 to 2.66, 660 participants, low quality of evidence.• Congestive heart failure: RR 0.22, 95% CI 0.04 to 1.34, 311 participants, low quality of evidence.Beta-blockers significantly reduced the occurrence of the following endpoints.• Ventricular arrhythmias: RR 0.37, 95% CI 0.24 to 0.58, number needed to treat for an additional beneficial outcome (NNTB) 29, 2292 participants, moderate quality of evidence.• Supraventricular arrhythmias: RR 0.44, 95% CI 0.36 to 0.53, NNTB six, 6420 participants, high quality of evidence.• On average, beta-blockers reduced length of hospital stay by 0.54 days (95% CI -0.90 to -0.19, 2450 participants, low quality of evidence). NON-CARDIAC SURGERY (36 trials)We found a potential increase in the occurrence of the following outcomes with the use of beta-blockers.• All-cause mortality: RR 1.24, 95% CI 0.99 to 1.54, 11,463 participants, low quality of evidence.Whereas no clear evidence of an effect was noted when all studies were analysed, restricting the meta-analysis to low risk of bias studies revealed a significant increase in all-cause mortality with the use of beta-blockers: RR 1.27, 95% CI 1.01 to 1.59, number needed to treat for an additional harmful outcome (NNTH) 189, 10,845 participants.• Cerebrovascular events: RR 1.59, 95% CI 0.93 to 2.71, 9150 participants, low quality of evidence.Whereas no clear evidence of an effect was found when all studies were analysed, restricting the meta-analysis to low risk of bias studies revealed a significant increase in cerebrovascular events with the use of beta-blockers: RR 2.09, 95% CI 1.14 to 3.82, NNTH 255, 8648 participants.Beta-blockers significantly reduced the occurrence of the following endpoints.• AMI: RR 0.73, 95% CI 0.61 to 0.87, NNTB 72, 10,958 participants, high quality of evidence.• Myocardial ischaemia: RR 0.43, 95% CI 0.27 to 0.70, NNTB seven, 1028 participants, moderate quality of evidence.• Supraventricular arrhythmias: RR 0.72, 95% CI 0.56 to 0.92, NNTB 111, 8794 participants, high quality of evidence.Beta-blockers significantly increased the occurrence of the following adverse events.• Hypotension: RR 1.50, 95% CI 1.38 to 1.64, NNTH 15, 10,947 participants, high quality of evidence.• Bradycardia: RR 2.24, 95% CI 1.49 to 3.35, NNTH 18, 11,083 participants, moderate quality of evidence.We found no clear evidence of an effect of beta-blockers on the following outcomes.• Ventricular arrhythmias: RR 0.64, 95% CI 0.30 to 1.33, 526 participants, moderate quality of evidence.• Congestive heart failure: RR 1.17, 95% CI 0.93 to 1.47, 9223 participants, moderate quality of evidence.• Length of hospital stay: mean difference -0.27 days, 95% CI -1.29 to 0.75, 601 participants, low quality of evidence.
Authors' conclusions:
According to our findings, perioperative application of beta-blockers still plays a pivotal role in cardiac surgery , as they can substantially reduce the high burden of supraventricular and ventricular arrhythmias in the aftermath of surgery. Their influence on mortality, AMI, stroke, congestive heart failure, hypotension and bradycardia in this setting remains unclear.In non-cardiac surgery, evidence from low risk of bias trials shows an increase in all-cause mortality and stroke with the use of beta-blockers. As the quality of evidence is still low to moderate, more evidence is needed before a definitive conclusion can be drawn. The substantial reduction in supraventricular arrhythmias and AMI in this setting seems to be offset by the potential increase in mortality and stroke.
Protection of myocardium from ischaemia involves detection and recognition of early changes in myocardial function associated with ischaemia as well as use of techniques and agents designed to alleviate or ameliorate ischaemia. However, the decision of which agent to employ depends not only upon the effects of a particular therapy but also the interaction between the therapeutic agent and anaesthetics. Nitroglycerine, beta-blockers, calcium antagonists, and intra-aortic balloon counterpulsation all may have beneficial effects in conscious patients but variable degrees of effectiveness during anaesthesia. Similarly, nitroprusside must be used with caution due to its additive effects upon anaesthesia-induced vasodilation. Inotropes may be needed to support the circulation during anaesthesia, whereas they would only be used with left ventricular failure in conscious patients. Vasoconstrictors may improve subendocardial perfusion and be of particular benefit in patients with pulmonary hypertension, as mild hypotension induced by anaesthesia may significantly decrease right ventricular perfusion. The choice of agents to be used for myocardial protection ultimately depend upon clinical decisions regarding coronary blood supply and myocardial oxygen demand. The availability of several different classes of agents capable of altering a specific physiological variable allows a wide variety of clinical situations to be effectively managed.
This article presents information concerning the cause, classification, and treatment of patients with hypertension and covers anesthesia considerations in the patient with hypertension. Although the patient with controlled hypertension possesses little increase in perioperative morbidity or mortality risk, the patient with uncontrolled systemic hypertension is considered to have a minor predictor for perioperative events and continues to pose a challenge and questions in management for the anesthesiologist.
This study was designed to determine the safety and efficacy of 100-mg and 200-mg bolus doses of esmolol in the prevention of intubation-associated hypertension, tachycardia, ST depression, and dysrhythmias. Forty-five patients undergoing noncardiac surgery were randomly allocated to receive either placebo, esmolol, 100 mg, or esmolol, 200 mg, intravenously, 90 seconds prior to intubation. Both doses of esmolol decreased the mean maximum increase in heart rate and rate-pressure product by approximately 36% [P < 0.01 y placebo), and attenuated these increases over the first 90 seconds postintubation. No effect on blood pressure was observed. Ventricular dysrhythmias occurred in 7 of 15 patients following placebo versus 4 of 30 patients receiving esmolol [P < 0.05). No difference in any variable was detected between the two esmolol groups at any time. The incidence of hypotension and bradycardia was no greater following esmolol than after placebo, nor was esmolol associated with cardiac conduction disturbances or wheezing. It was concluded that bolus doses of esmolol safely attenuate the hemodynamic response to intubation and decrease the incidence of ventricular dysrhythmias.
Increased activity or inadequate inhibition of the autonomic nervous system is often the cause of perioperative hypertension. The goal of treatment is to maintain an adequate balance between myocardial oxygen supply and demand. Newer agents, such as nicardipine and fenoldopam, may offer potential advantages over older agents. The cost:benefit ratio of therapy with these newer agents must also be considered. Despite the fact that perioperative hypertension is aggressively treated, there are no long-term, large-scale study data indicating that this treatment affects long-term patient outcomes.
Wave propagation and transient response of an infinite functionally graded circular plate under a point impact load are studied. The effective material properties are assumed to vary as a power form of the thickness coordinate. Considering the effects of transverse shear deformation and rotary inertia, the governing equations and analytic dispersion relation of the plate are obtained. Using the dispersion relation and integral transforms, exact integral solutions of the functionally graded plate under a point impact load are obtained. The influence of volume fraction distributions on wave propagation and transient response of functionally graded plates is discussed in detail.
Perioperative cardiac morbidity is the leading cause of death in patients with coronary artery disease (CAD) undergoing non-cardiac surgery. It is usually defined as the occurrence of unstable myocardial ischaemia, congestive heart failure, myocardial infarction, ventricular tachydysrhythmias or sudden cardiac death. A plethora of clinical studies published over the past decades have analysed cardiac risk in conjunction with non-cardiac surgery. The volume of this literature is an illustration of the complexity of the problem and its multifactorial genesis. Data from several of the more recent studies would suggest that cardiac outcome has improved, despite the fact that more complex surgery is performed on older patients than before. Several possible mechanisms which, per se, might reduce cardiac morbidity
Chez le patient sans trouble cardiovasculaire, la laryngoscopie et l'intubation entraînent une augmentation tensionnelle très variable, en moyenne de 40 à 50%, avec un accroissement de la fréquence cardiaque de 20 %. Ces modifications résultent d'une stimulation sympathique également à l'origine de troubles du rythme. L'élévation tensionnelle est plus importante chez les patients hypertendus mal équilibrés. En cas d'insuffisance coronaire, des épisodes d'ischémie myocardique surviennent pour plus de la moitié des patients quand aucune méthode spécifique de protection n'est employée. Parmi les différents moyens de prévention proposés, les morphinomimétiques ont une action efficace et constante mais au prix d'un risque de dépression respiratoire postopératoire. La lidocaïne a un effet très partiel et souvent insuffisant. Les bêta-bloquants ont une action beaucoup plus prononcée sur la prévention de la tachycardie que de la poussée hypertensive suivant l'intubation, ce qui est intéressant chez le patient coronarien. Dans le cadre de la prévention, les autres produits (clonidine, inhibiteurs calciques) semblent soit moins efficaces soit moins maniables. En pratique anesthésique courante, il faut sélectionner les patients chez qui la prévention est indiquée. Le moyen le plus simple est le recours aux morphinomimétiques à dose efficace. Dans certains cas, l'association de dérivés nitrés ou de bêta-bloquants peut être utile. En l'absence de prévention, chez les patients dont l'hypertension est menaçante, les antihypertenseurs de demi-vie brève (bêta-bloquants, inhibiteurs calciques) trouvent leur indication.
Observations of heart rate, rhythm and arterial pressure during induction of anaesthesia, intubation of the trachea, and commencement of surgery were made in 42 patients divided into three comparable groups. Group 1, the control group of 15 patients, received an intravenous placebo injection prior to induction of anaesthesia; group 2, 14 patients, was given an intravenous injection of 2 mg of metoprolol, a beta‐adrenoreceptor blocking agent; group 3, 13 patients, received 4 mg metoprolol intravenously. In the placebo group, significant mean increases in heart rate of 27 and 38 beats/minute were noted at induction of anaesthesia and at intubation of the trachea respectively (p< 0·001). Heart rate was significantly reduced after metoprolol in groups 2 and 3 before anaesthesia (7·6 beats/minute, p < 0·05; and 12·9 beats/minute, p < 0·001). The increases which occurred after induction of anaesthesia (13·7 beats/minute, p < 0·01; and 15 beats/minute, p < 0·001), were significantly less than those in the control group (p < 0·05). Further increases in heart rate of 10 and 11 beats/minute were noted at intubation in groups 2 and 3 respectively (significantly less than placebo, p< 0·05).
Although no change in systolic arterial pressure was noted in the control group following induction of anaesthesia and the mean increase after intubation was modest (9·8 mmHg), increases in three patients exceeded 50 mmHg. Arterial pressure was reduced by metoprolol in the period before anaesthesia in groups 2 and 3 by 7·1 mmHg (p< 0·05) and 8·1 mmHg (p < 0·01). Again no changes were noted at induction. Mean increases in blood pressure after intubation did not exceed control levels, and increases of 20–30 mmHg were noted in six patients.
Cardiac rhythm disturbances, of short duration and of no apparent clinical consequence, were noted in association with induction of anaesthesia and intubation. ST segment changes were commonest and occurred in eight patients; five of these were in the placebo group. Six patients had short‐lived ventricular and supraventricular ectopics at induction or intubation of the trachea.
To determine if a relationship exists between perioperative myocardial ischemia (ST segment depression greater than or equal to 0.1 mV) and postoperative myocardial infarction (PMI), nonparticipating observers recorded all ECG, hemodynamic, and other events between arrival of patients in the operating room and onset of cardiopulmonary bypass during 1,023 elective coronary artery bypass operations (CABG). The roles of preoperative patient characteristics, quality of the operation limited by disease as rated by the surgeon and duration of ischemic cardiac arrest as risk factors for PMI also were quantified. ECG ischemia occurred in 36.9% of all patients, with almost half the episodes occurring before induction of anesthesia. PMI was almost three times as frequent in patients with ischemia (6.9% vs. 2.5%) and was independent of when ischemia occurred. Ischemia was related significantly to tachycardia but not hypertension nor hypotension and was frequent in the absence of any hemodynamic abnormalities. The anesthesiologist whose patients had the highest rate of tachycardia and ischemia had the highest rate of PMI. Although neither single nor multiple preoperative patient characteristics related to PMI, suboptimal quality of operation and prolonged ischemic cardiac arrest increased the likelihood of PMI independent of the occurrence of myocardial ischemia. The authors conclude that perioperative myocardial ischemia is common in patients undergoing CABG, occurs randomly as well as in response to hemodynamic abnormalities, and is one of three independent risk factors the authors identified as related to PMI. PMI is unrelated to preoperative patient characteristics such as ejection fraction and left main coronary artery disease, and its frequency will relate primarily to perioperative management rather than patient selection.
Hypertension and tachycardia following laryngoscopy and tracheal intubation during various forms of light general anesthesia are well documented. Methods to avoid these potentially harmful responses while preserving the advantages of minimal anesthetic depth in critically ill patients have been sought. Intratracheal administration of lidocaine, 4%, is frequently used in clinical practice; however, there has been no objective evaluation of its effectiveness in blocking the circulatory responses to intubation. This study in cardiac patients anesthetized with morphine and nitrous oxide indicates that a hypertensive response in patients anesthetized with morphine and nitrous oxide can be significantly decreased by a simple intratracheal spray with lidocaine, 4%.
Hemodynamic effects of propranolol during coronary artery surgery were investigated in 26 patients who chronically took propranolol and who received a standardized morphine/diazepam/pancuronium/halothane anesthetic. Effects were shown by correlating logarithm of the plasma propranolol concentrations versus percentage change in hemodynamics following stressful events (induction, intubation, skin incision, sternotomy, and sternal retraction). Log propranolol and hemodynamics following cardiopulmonary bypass also were correlated. A broad range of propranolol levels were observed. Levels (range and mean +/- SD) were preinduction 0-96 (25.6 +/- 21.6) ng/ml; preincision 0-86 (27.2 +/- 24.4) ng/ml; and sternal retraction 0-92 (28.2 +/- 25.4) ng/ml. The range of hemodynamic responses to stressful events also was broad. Representative changes between preincision control and sternotomy were (range and mean +/- SD): HR-8-30 (7 +/- 10) beats/min; PCWP 1-21 (8.5 +/- 4.6) mmHg; CI -0.2-1.1 (-0.2 +/- 0.7) 1 X min-1 X m-2, and SVR -244-1,288 (310 +/- 388) dyn X s X cm-3. By the time of sternal retraction, CI had declined from preincision values in 14 patients. Linear regression analysis demonstrated an inverse correlation between log propranolol and magnitude of HR, MAP, PCWP, and CI response to stressful stimulation. A direct but statistically weaker correlation with SVR also was seen. Significant correlations between log propranolol versus hemodynamic response to anesthetic induction and versus postcardiopulmonary bypass hemodynamics were not observed.
Left ventricular performance was monitored serially in 25 patients during laryngoscopy and intubation in the anesthetic induction period before elective coronary artery bypass surgery using the labeled equilibrium blood pool and the computerized nuclear probe. Left ventricular ejection fraction was obtained preoperatively, after induction of anesthesia but before endotracheal intubation, immediately after intubation, and at 1 minute intervals thereafter for 10 minutes. In all patients, there was an immediate decrease (mean 16%) in left ventricular ejection fraction accompanying the reflex hypertension and tachycardia occurring during laryngoscopy and endotracheal intubation; it was significantly depressed for 3 minutes with the concomitant hemodynamic changes. Seven patients did not demonstrate a recovery of left ventricular ejection fraction to the preintubation value. In 10 healthy noncardiac patients undergoing orthopedic surgery, after an identical anesthetic induction sequence and intubation, there was a similar decrease in ejection fraction, but of shorter duration. In these patients the recovery of left ventricular performance preceded the recovery of blood pressure and heart rate. This study demonstrates that profound decreases in left ventricular performance accompany the reflex hypertension and tachycardia occurring during endotracheal intubation and that there is persisting depression of left ventricular function in some patients with coronary artery disease. These findings indicate the potential utility of the computerized nuclear probe for monitoring ventricular performance during this critical period.