Inotropic and lusitropic effects of levosimendan and milrinone assessed by strain echocardiography-A randomised trial.

BACKGROUND: We compared the direct inotropic and lusitropic effects of two inodilators, milrinone and levosimendan in patients after aortic valve replacement for aortic stenosis. METHODS: In this randomised, blinded study, 31 patients with normal LV function, were randomised to either levosimendan (0.1 and 0.2 µg/kg/min, n = 15) or milrinone (0.4 and 0.8 µg/kg/min, n = 16) after aortic valve replacement. The effects on LV performance, LV strain, systolic (SR-S) and early diastolic (SR-E) strain rate were assessed by a pulmonary artery catheter and transoesophageal two-dimensional speckle tracking echocardiography of the LV inferior wall. To circumvent the inodilator-induced hemodynamic changes on LV systolic and diastolic deformation, central venous pressure (CVP), systolic artery pressure (SAP), and heart rate were maintained constant by colloid infusion, phenylephrine-induced vasoconstriction and atrial pacing, respectively, during drug infusion. RESULTS: Both inotropic agents induced a dose-dependent increase in cardiac index and stroke volume index by approximately 20% at the highest infusion rates with no differences between groups (P = .139 and .249, respectively). CVP, pulmonary capillary wedge pressure, SAP and heart rate were maintained constant in both groups. LV strain and SR-S increased with both agents, dose-dependently, by 17%-18% and 25%-30%, respectively, at the highest infusion rates, with no difference between groups (P = .434 and .284, respectively). Both agents improved early LV relaxation with no differences between groups (P = .637). At the higher doses, both agents increased SR-E by 30%. CONCLUSIONS: At clinically relevant infusion rates and a certain increase in LV performance the direct inotropic and lusitropic of milrinone and levosimendan were comparable.

Vasopressin and nitroglycerin decrease portal and hepatic venous pressure and hepato-splanchnic blood flow.

BACKGROUND: Various methods are used to reduce venous blood pressure in the hepato-splanchnic circulation, and hence minimise blood loss during liver surgery. Previous studies show that combination of vasopressin and nitroglycerin reduces portal pressure and flow in patients with portal hypertension, and in this study we investigated this combination in patients with normal portal pressure. METHOD: In all, 13 patients were studied. Measurements were made twice to confirm baseline (C1 and BL), during vasopressin infusion 4.8 U/h (V), and during vasopressin infusion combined with nitroglycerin infusion (V + N). Portal venous pressure (PVP), hepatic venous pressure (HVP), central haemodynamics and arterial and venous blood gases were obtained at each measuring point, and portal (splanchnic) and hepato-splanchnic blood flow changes were calculated. RESULTS: Vasopressin alone did not affect PVP, whereas HVP increased slightly. In combination with nitroglycerin, PVP decreased from 10.1 ± 1.6 to 8.9 ± 1.3 mmHg (P < 0.0001), and HVP decreased from 7.9 ± 1.9 to 6.2 ± 1.3 mmHg (P = 0.001). Vasopressin reduced portal blood flow by 47 ± 19% and hepatic venous flow by 11 ± 18%, respectively. Addition of nitroglycerin further reduced portal- and hepatic flow by 55 ± 13% and 30 ± 13%, respectively. Vasopressin alone had minor effects on central haemodynamics, whereas addition of nitroglycerin reduced cardiac index (3.2 ± 0.7 to 2.7 ± 0.5; P < 0.0001). The arterial-portal vein lactate gradient was unaffected. CONCLUSION: The combination of vasopressin and nitroglycerin decreases portal pressure and hepato-splanchnic blood flow, and could be a potential treatment to reduce bleeding in liver resection surgery.

Load-dependence of myocardial deformation variables - a clinical strain-echocardiographic study.

BACKGROUND: The effects of left ventricular (LV) loading on myocardial deformation variables are not well-studied in the clinical setting. In the present study, we evaluated the effects of isolated changes in preload, afterload and heart rate on LV longitudinal strain, systolic (SR-S) and early diastolic strain rate (SR-E) in post-cardiac surgery patients. METHODS: Twenty-one patients were studied early after cardiac surgery. Longitudinal myocardial strain and SR were analysed off-line using 2-D speckle echocardiography. The experimental protocol consisted of three consecutive interventions: (1) preload was increased by passive leg elevation, (2) afterload was increased by an infusion of phenylephrine to increase arterial blood pressure by 10-15% and (3) heart rate was increased 10% and 20% by atrial pacing. During both the preload and afterload challenges heart rate was kept constant by atrial pacing. Central venous pressure was kept constant during pacing by infusion of hetastarch/albumin. RESULTS: The increase in preload increased LV strain, SR-S and SR-E by 20%, 11% and 17%, respectively. The phenylephrine-induced increase in afterload, did not affect LV strain, SR-S or SR-E. LV strain was not affected while SR-S and SR-E increased by pacing-induced heart rate increase. CONCLUSION: After cardiac surgery, systolic and early diastolic strain rate are dependent on both preload and heart rate, while neither of these variables was afterload-dependent. LV strain was preload-dependent but not affected by atrial pacing. When evaluating the direct effects of various pharmacological or other interventions on myocardial contractility and relaxation, preload and heart rate must be controlled.

Vasopressin-induced changes in splanchnic blood flow and hepatic and portal venous pressures in liver resection.

BACKGROUND: To minimize blood loss during hepatic surgery, various methods are used to reduce pressure and flow within the hepato-splanchnic circulation. In this study, the effect of low- to moderate doses of vasopressin, a potent splanchnic vasoconstrictor, on changes in portal and hepatic venous pressures and splanchnic and hepato-splanchnic blood flows were assessed in elective liver resection surgery. METHODS: Twelve patients were studied. Cardiac output (CO), stroke volume (SV), mean arterial (MAP), central venous (CVP), portal venous (PVP) and hepatic venous pressures (HVP) were measured, intraoperatively, at baseline and during vasopressin infusion at two infusion rates (2.4 and 4.8 U/h). From arterial and venous blood gases, the portal (splanchnic) and hepato-splanchnic blood flow changes were calculated, using Fick's equation. RESULTS: CO, SV, MAP and CVP increased slightly, but significantly, while systemic vascular resistance and heart rate remained unchanged at the highest infusion rate of vasopressin. PVP was not affected by vasopressin, while HVP increased slightly. Vasopressin infusion at 2.4 and 4.8 U/h reduced portal blood flow (-26% and -37%, respectively) and to a lesser extent hepato-splanchnic blood flow (-9% and -14%, respectively). The arterial-portal vein lactate gradient was not significantly affected by vasopressin. Postoperative serum creatinine was not affected by vasopressin. CONCLUSION: Short-term low to moderate infusion rates of vasopressin induced a splanchnic vasoconstriction without metabolic signs of splanchnic hypoperfusion or subsequent renal impairment. Vasopressin caused a centralization of blood volume and increased cardiac output. Vasopressin does not lower portal or hepatic venous pressures in this clinical setting.

Bone cement implantation syndrome in cemented hemiarthroplasty for femoral neck fracture: incidence, risk factors, and effect on outcome.

BACKGROUND: Bone cement implantation syndrome (BCIS) is characterized by hypoxia, hypotension, and loss of consciousness occurring around the time of bone cementation. Using a recently proposed severity classification of BCIS, we estimated the incidence of and risk factors for BCIS and its impact on mortality in cemented hemiarthroplasty for femoral neck fractures. METHODS: In this retrospective study, 1016 patients undergoing cemented hemiarthroplasty were included. Medical history and medication were obtained from medical records. Anaesthesia charts for all patients were reviewed for mean arterial pressure, arterial oxygen saturation, and heart rate before, during, and after cementation. Each patient was classified as having no BCIS (grade 0) or BCIS grade 1, 2, or 3, depending on the degree of hypotension, arterial desaturation, or loss of consciousness around cementation. RESULTS: The incidence of BCIS grade 1, 2, and 3 were 21%, 5.1%, and 1.7%, respectively. Early mortality in BCIS grade 1 (9.3%) did not differ significantly from BCIS grade 0 (5.2%), while early mortality in BCIS grade 2 (35%) and grade 3 (88%) were significantly higher when compared with grades 0 and 1. Early mortality was also higher in BCIS grade 3 when compared with grade 2. Independent predictors for severe BCIS were: ASA grade III-IV, chronic obstructive pulmonary disease, and medication with diuretics or warfarin. Severe BCIS was associated with 16-fold increase in mortality. CONCLUSIONS: BCIS is a commonly occurring phenomenon in cemented hemiarthroplasty and severe BCIS has a huge impact on early and late mortality.

Nitroglycerine and patient position effect on central, hepatic and portal venous pressures during liver surgery.

BACKGROUND: To reduce blood loss during liver surgery, a low central venous pressure (CVP) is recommended. Nitroglycerine (NG) with its rapid onset and offset can be used to reduce CVP. In this study, the effect of NG on portal and hepatic venous pressures (PVP and HVP) in different body positions was assessed. METHODS: Thirteen patients undergoing liver resection were studied. Cardiac output (CO), mean arterial pressure (MAP) and CVP were measured. PVP and HVP were measured using tip manometer catheters at baseline (BL) in horizontal position; during NG infusion, targeting a MAP of 60 mmHg, with NG infusion and the patient placed in 10 head-down position. RESULTS: NG infusion reduced HVP from 9.7 ± 2.4 to 7.2 ± 2.4, PVP from 12.3 ± 2.2 to 9.7 ± 3.0 and CVP from 9.8 ± 1.9 to 7.2 ± 2.1 mmHg at BL. Head-down tilt during ongoing NG resulted in increases in HVP to 8.2 ± 2.1, PVP to 10.7 ± 3 and CVP to 11 ± 1.9 mmHg. CO at BL was 6.3 ± 1.1, which was reduced by NG to 5.8 ± 1.2. Head-down tilt together with NG infusion restored CO to 6.3 ± 1.0 l/min. CONCLUSION: NG infusion leads to parallel reductions in CVP, HVP and PVP at horizontal body position. Thus, CVP can be used to guide NG dosage and fluid administration at horizontal position. NG infusion can be used to reduce HVP. Head-down tilt can be used during NG infusion to improve both blood pressure and CO without substantial increase in liver venous pressure. In head-down tilt, CVP dissociates from HVP and PVP.

Effect of patient position and PEEP on hepatic, portal and central venous pressures during liver resection.

BACKGROUND: It has been suggested that blood loss during liver resection may be reduced if central venous pressure (CVP) is kept at a low level. This can be achieved by changing patient position but it is not known how position changes affect portal (PVP) and hepatic (HVP) venous pressures. The aim of the study was to assess if changes in body position result in clinically significant changes in these pressures. METHODS: We studied 10 patients undergoing liver resection. Mean arterial pressure (MAP) and CVP were measured using fluid-filled catheters, PVP and HVP with tip manometers. Measurements were performed in the horizontal, head up and head down tilt position with two positive end expiratory pressure (PEEP) levels. RESULTS: A 10° head down tilt at PEEP 5 cm H(2) O significantly increased CVP (11 ± 3 to 15 ± 3 mmHg) and MAP (72 ± 8 to 76 ± 8 mmHg) while head up tilt at PEEP 5 cm H(2) O decreased CVP (11 ± 3 to 6 ± 4 mmHg) and MAP (72 ± 8 to 63 ± 7 mmHg) with minimal changes in transhepatic venous pressures. Increasing PEEP from 5 to 10 resulted in small increases, around 1 mmHg in CVP, PVP and HVP. There was no significant correlation between changes in CVP vs. PVP and HVP during head up tilt and only a weak correlation between CVP and HVP by head down tilt. CONCLUSIONS: Changes of body position resulted in marked changes in CVP but not in HVPs. Head down or head up tilt to reduce venous pressures in the liver may therefore not be effective measures to reduce blood loss during liver surgery.

Patients' assessment of 4-week recovery after ambulatory surgery.

BACKGROUND: patients' own assessment of recovery after ambulatory surgery has not been well studied. The aim was to study patients' self-assessed recovery, the occurrence and time course of post-operative problems in relation to the type of ambulatory surgery. METHODS: a questionnaire was filled in by 355 patients at five time points: pre-operative, first day at home, 1, 2 and 4 weeks post-operatively. Consecutive patients who underwent either inguinal hernia repair (IHR), arthroscopic procedures (AS) or cosmetic breast augmentation (CBA) were included. RESULTS: unplanned return to hospital was rare (3/355). Health care contacts were noted for 9% of the patients during the first week; a total of 70 contacts occurred during the entire period. Pain was the most frequently reported symptom; 40% of the patients reported pain or mobility problems at 1 week, 28% after 2 weeks and 20% after 4 weeks. Pre-operative pain was associated with an increased level of pain during the early post-operative course, in the recovery room and at 1 week post-operatively. IHR was associated with an overall rapid recovery, while AS patients experienced a slower restitution. All AS patients who reported pain after 4 weeks had reported pain problems already pre-operatively. Pain was not present pre-operatively in the CBA group, but was common at 1 and 2 post-operative weeks and was still reported by 11% at 4 weeks. CONCLUSION: self-assessed recovery was found to cover several weeks with procedure-specific recovery patterns. Pain and mobility impairment were still frequently reported 4 weeks post-operatively.

Pulmonary haemodynamics and right ventricular function during cemented hemiarthroplasty for femoral neck fracture.

BACKGROUND: Bone cement implantation syndrome (BCIS) is characterised by hypoxia, hypotension and loss of consciousness occurring early after bone cementation. The haemodynamic perturbations during BCIS have not been extensively studied, particularly not in patients with femoral neck fracture. We evaluated the effects of cemented hemiarthroplasty, in these patients, on pulmonary haemodynamics, right ventricular performance, intrapulmonary shunting and physiological dead space. METHODS: Fifteen patients undergoing cemented hemiarthroplasty because of femoral neck fracture were included. Surgery was performed under total intravenous anaesthesia in the lateral position. All patients were catheterised with a radial and pulmonary artery catheter, for continuous measurements of mean arterial pressure (MAP), pulmonary arterial pressure (PAP), cardiac output, mixed venous oxygen saturation, right ventricular end-diastolic volume (RVEDV) and right ventricular ejection fraction (RVEF). Haemodynamic measurements and blood gas analyses were performed after induction of anaesthesia, during surgical stimulation before and immediately after bone cementation and prosthesis insertion, 10 and 20 min after insertion and during skin closure. RESULTS: After bone cementation and prosthesis insertion, MAP (-10%), cardiac index (-10%) and stroke volume index (-10%) decreased, while PAPs (10-15%) and the pulmonary vascular resistance index (45%) increased. RVEF decreased by 10-20%, while the RVEDV index increased by 10%. Pulmonary haemodynamic and RV variables changed progressively with time, while intra-pulmonary shunting and physiological dead space increased immediately after prosthesis insertion and then returned to baseline. CONCLUSIONS: Cemented hemiarthroplasty in patients with femoral neck fracture causes a pronounced pulmonary vasoconstriction and an impairment of RV function accompanied by pulmonary ventilation/perfusion abnormalities.

Patient assessed health profile: a six-month quality of life questionnaire survey after day surgery.

AIM: Patient assessed quality of life is one of the principal end-points after day surgery. The aim of the present study was to describe the natural course, differences and timing of final evaluation for three common day surgical procedures; inguinal hernia repair (IHR), arthroscopic procedures (AS); and cosmetic breast augmentation (CBA). METHOD: A total of 355 patients prospectively completed an extended eight-item EQ-5D questionnaire (pain, mobility, mood, self-care, activities, sleep, sex, need for analgesic), preoperatively and at one, three and six months postoperatively. RESULTS: Pain and mobility problems were frequently reported prior to surgery among IHR and AS patients, while CBA patients had less deviation from normal in the preoperative health profile. The proportions of patients reporting surgery-related deviations were 35%, 20% and 5% at one, three and six months respectively. After one month, 50% of AS patients still suffered subjective discomfort as compared to 13% and 20% of the IHR and CBA patients, respectively. Pain and ambulation problems were the most common symptoms in all groups. Six months after surgery, 94% of IHR, 89% of AS and 97% of CBA patients were fully recovered. CONCLUSIONS: No major morbidity or severe complications were observed and patients' satisfaction was high overall. We found procedure-specific changes in the postoperative health profile after day surgery. AS patients recovered more slowly compared with IHR and CBA patients. We conclude that time for final evaluation differs significantly between procedures.

Postoperative impact of regular tobacco use, smoking or snuffing, a prospective multi-center study.

BACKGROUND: The aim was to study the effects of different tobacco administration routes on pain and post-operative nausea and vomiting (PONV), following three common day surgical procedures: cosmetic breast augmentation (CBA), inguinal hernia repair (IHR) and arthroscopic procedures (AS). We have prospectively investigated the effects of regular tobacco use in ambulatory surgery. METHODS: The 355 allocated patients were followed during recovery and the first day at home. RESULTS: Thirty-two percent of the patients used tobacco regularly, 33% of CBA, 27% of IHR and 34% of AS. Pain was well controlled in the post-anesthesia care unit at rest; during ambulation, 37% of all patients reported VAS>3. Tobacco use had no impact on early post-operative pain. Post-operative nausea was experienced by 30% of patients during recovery while in hospital. On day 1, 14% experienced nausea. We found a significant reduction of PONV among tobacco users (smoking and/or snuffing). Smoking or snuffing reduced the risk of PONV by nearly 50% in both genders on the day of surgery and at the first day at home. The reduction of PONV was equal, regardless of tobacco administration routes. CONCLUSION: We found that regular use of tobacco, both by smoking and snuffing, had a significant effect on PONV during the early post-operative period. Non-tobacco users undergoing breast surgery were found to have the highest risk for PONV. We could not see any influence of nicotine use on post-operative pain. Thus, it seems of value to identify regular tobacco use, not only smoking, as a part of the pre-operative risk assessment.

Cardiopulmonary bypass in humans--jejunal mucosal perfusion increases in parallel with well-maintained microvascular hematocrit.

BACKGROUND: An imbalance between splanchnic oxygen supply and demand occurs during cardiopulmonary bypass (CPB) in man, which might disrupt the intestinal mucosal barrier function. The aim of the present study was to evaluate the effects of mild hypothermic CPB on intestinal mucosal perfusion in man undergoing cardiac surgery. Additionally we aimed to identify variables, which independently could predict changes of intestinal mucosal microcirculatory variables during CPB. METHODS: Jejunal mucosal perfusion (JMP), jejunal mucosal hematocrit (JMHt), red blood cell (RBC) velocity and arteriolar vasomotion using endoluminal jejunal laser Doppler flow metry were studied in eight cardiac surgical patients before and during CPB at a temperature of 34 degrees C. RESULTS: Cardiopulmonary bypass and the accompanied hemodilution (25-30%) induced a 44% increase in JMP (P < 0.05) and a 42% increase in RBC velocity (P < 0.01), with no change in JMHt. The oscillation amplitude of JMP, at a fundamental frequency of 2.8 cycles min(-1), increased with 175% (P < 0.05) during CPB. Splanchnic oxygen extraction increased by 64% during CPB (P < 0.05). Stepwise multiple regression analysis identified systemic hematocrit, arterial O2 and CO2 tension and splanchnic oxygen extraction as independent predictors of RBC velocity during CPB (R2=0.63, P < 0.001). The oscillation amplitude of JMP was predicted by RBC velocity and splanchnic oxygen extraction (R2= 0.68, P <0.0001). CONCLUSIONS: The increase in RBC velocity and enhanced arteriolar vasomotion, as well as maintained jejunal mucosal hematocrit, are microcirculatory, compensatory mechanisms for the splanchic oxygen supply/demand mismatch seen during cardiopulmonary bypass in humans.

Gender differences in patients with severe aortic stenosis: impact on preoperative left ventricular geometry and function, as well as early postoperative morbidity and mortality.

OBJECTIVE: In patients with severe aortic stenosis, we studied the impact of gender on preoperative left ventricular geometry and function, as well as on early postoperative mortality and morbidity. METHODS: Prospective Doppler echocardiographic evaluation was performed in 99 female patients and 96 males. RESULTS: The patients had severe aortic stenosis and the mean pressure gradients were similar in females and males. Left ventricular diastolic volume adjusted for body surface area (BSA) was larger in males, 55+/-17.4 ml/m2 versus 43+/-13.1 mL/m2 (mean+/-standard deviation; P = 0.0001). The ejection fraction was similar in females (55+/-14%) and males (55+/-13%), and patients of both sexes had significantly lower stroke volume and cardiac index than healthy controls. The relative wall thickness (wall thickness/diastolic diameter ratio) was higher (P = 0.03) in females (0.47+/-0.10) than in males (0.43+/-0.10) Consequently, the diastolic diameter/wall thickness ratio (a substitute for wall tension) was higher (P = 0.02) in males (4.2+/-0.99) than in females (3.9+/-0.80). Compared with survivors, patients who died within 30 days of the operation (n = 17, 11 females) had a smaller body surface area (1.70+/-0.19 vs. 1.82+/-0.19 m2, P = 0.012), smaller left ventricular outflow tract (20.8+/-0.21 vs. 22.0+/-0.22 mm, P = 0.023), higher incidence of abnormal intraventricular flow velocity (33 vs. 8%, P = 0.018) and increased relative wall thickness (0.52+/-0.17 vs. 0.45+/-0.09 P = 0.039). Gender was of no independent importance for early mortality when age and left ventricular outflow tract diameter were accounted for. CONCLUSIONS: Cardiac adaptation to aortic stenosis seems to be influenced by gender, males presenting larger left ventricular volumes and higher wall tension. The echocardiographic findings of a narrow left ventricular outflow tract, abnormally increased intraventricular velocity and increased relative wall thickness identified patients with increased risk of early postoperative mortality. However gender had no independent impact on early postoperative outcome.

Atrial natriuretic peptide attenuates pacing-induced myocardial ischemia during general anesthesia in patients with coronary artery disease.

UNLABELLED: Atrial natriuretic peptide (ANP) exerts a dilatory effect on coronary arteries in humans. We investigated the effects of ANP on pacing-induced myocardial ischemia during enflurane anesthesia in patients with coronary artery disease (CAD). In 20 patients with CAD, myocardial ischemia was induced by atrial pacing before and after an i.v. infusion of ANP (50 mg x kg(-1) min(-1), n = 10) or placebo (n = 10). We studied the effects of ANP or placebo on pacing-induced changes in central hemodynamics, myocardial blood flow and regional myocardial indices of lactate uptake (RMLU), and oxygen consumption (RMVO2) and extraction (RMO2E). ST-segment depression was less pronounced during pacing with ANP compared with control pacing (-0.09 +/- 0.01 vs -0.24 +/- 0.02 mV; P < 0.001). RMLU decreased to -11.1 micromol/min during control pacing compared with -0.7 micromol/min during pacing with ANP (P < 0.01). ANP did not affect pacing-induced changes in RMVO2, RMO2E, or the rate pressure product. Placebo did not affect pacing-induced changes in ST-segment depression or RMLU. In conclusion, ANP attenuates ischemic ST-segment depression and lactate release during pacing-induced myocardial ischemia in patients with CAD. The antiischemic effect of ANP was not accompanied by any improvement in the regional myocardial oxygen supply/demand relationship. IMPLICATIONS: We evaluated the effects of i.v. atrial natriuretic peptide (50 ng x kg(-1) x min(-1)) on pacing-induced myocardial ischemia during general anesthesia in patients with coronary artery disease. In contrast to placebo, atrial natriuretic peptide attenuated ST-segment depression and myocardial lactate production and improved left ventricular function during pacing-induced ischemia.

The effects of propofol on cerebral blood flow velocity and cerebral oxygen extraction during cardiopulmonary bypass.

UNLABELLED: We investigated the effects of burst-suppression doses of propofol on cerebral blood flow velocity (CBFV), cerebral oxygen extraction (COE), and dynamic autoregulation in 20 patients undergoing cardiac surgery. The experimental procedure was performed during nonpulsatile cardiopulmonary bypass (CPB) with stable hypothermia (32 degrees C) in fentanyl-anesthetized patients. Middle cerebral artery transcranial Doppler flow velocity, right jugular bulb oxygen saturation, and jugular venous pressure (JVP) were continuously measured. Dynamic autoregulation was tested by stepwise changes in mean arterial pressure (MAP) within a range of 40-80 mm Hg by sodium nitroprusside and phenylephrine before (control) and during propofol infusion, with a stable plasma concentration (approximately 9 microg/mL). Propofol induced a 35% decrease in CBFV (P < 0.0001) and a 10% decrease in COE (P < 0.05) compared with control. The slopes of the curves relating CBFV and COE to cerebral perfusion pressure (CPP = MAP - JVP) were less pronounced with propofol (P < 0.01 and P < 0.05, respectively). We conclude that propofol decreases CBFV and improves dynamic autoregulation during moderate hypothermic CPB. Furthermore, during propofol infusion, cerebral blood flow was in excess relative to oxygen demand, as indicated by the decrease in COE. IMPLICATIONS: In this study, we evaluated the effects of propofol on continuously measured cerebral blood flow velocity (CBFV) and cerebral oxygen extraction as a function of perfusion pressure. Propofol induced 35% and 10% decreases in CBFV and cerebral oxygen extraction, respectively. The slope of the curve relating cerebral perfusion pressure to CBFV decreased with propofol.

Perioperative transoesophageal echocardiography with low-dose dobutamine stress for evaluation of myocardial viability: a feasible approach?

BACKGROUND: The feasibility of low-dose dobutamine stress combined with transoesophageal echocardiography (TEE) to detect viable left ventricular myocardium was evaluated in 22 anaesthetised patients prior to sternotomy for elective coronary artery bypass grafting (CABG). METHODS: After baseline measurements, a dobutamine infusion beginning with 5 micrograms.kg-1.min-1 was started and eventually increased to 10 micrograms.kg-1.min-1. Viability was assessed as visual improvement of left ventricular wall motion (LVWM). The criteria for discontinuation of the infusion were: 1. any changes in LVWM, 2. an increase in preanaesthetic blood pressure exceeding 40 mmHg, and/or a > 20% increase in preanaesthetic heart rate compared to preanaesthetic levels. An off-line evaluation of LVWM was based upon visualisation of the left ventricle in a transgastric short-axis mid-papillary (mid-P) view, and the left ventricle was divided into anterior, septal, inferior, and lateral segments. Moreover, an off-line semiautomatic analysing system was used for assessing regional and global LVWM. With this analysis the effects on LVWM from changes in preload and afterload could be addressed. RESULTS: 19 patients showed a decreased LVWM in one or several segments at baseline. A total of 36 segments exhibited decreased LVWM (an average of 1.9 segments/patient). Of these, 22 segments (61%) improved with dobutamine, while 12 segments (33%) did not, and 2 (6%) became more dysfunctional. Another 6 segments with normal motion at baseline became dysfunctional with dobutamine. According to the off-line semiautomatic analysing system for LVWM, there were no statistically significant changes with dobutamine stimulation. Only one patient showed an increased postoperative aspartateaminotransferase (ASAT) value (3.0 mmol.l-1) but no ECG changes. CONCLUSION: Since we regard the visual assessment of LVWM as being more applicable for this protocol than the semiautomatic analysis, we conclude that low-dose dobutamine stress echocardiography seems to be a feasible method for detecting viable myocardium in the anaesthetised patient scheduled for elective CABG surgery. However, the semiautomatic analysis complemented our findings, since the variations in pre- and afterload did not significantly change the size of the left ventricle, which hereby would imply LVWM changes.

Effects of halothane and isoflurane on left ventricular diastolic function during surgical stress in patients with coronary artery disease.

BACKGROUND: The effects of inhalation anesthetics on left ventricular (LV) systolic function are well documented, while the effects of these agents on LV diastolic function have mainly been evaluated in animal studies, with conflicting results. METHODS: We investigated the effects of halothane and isoflurane, when used to control the stress response to sternotomy in 33 patients with coronary artery disease (CAD). LV early diastolic relaxation and end-diastolic stiffness were evaluated from mitral Doppler flow profiles, transesophageal two-dimensional echocardiography, and central hemodynamic measurements. Measurements were performed a) after induction of anesthesia, b) after volume loading, c) prior to surgery and d) during surgery, 10 min after introduction of the inhalation anesthetic. The effects of the anesthetics on Doppler indices reflecting early diastolic relaxation, and on the left ventricular end-diastolic pressure-area (LVED P/A) relationship, were studied. RESULTS: When data obtained during surgical stress were compared to the control situation, we found an increase in the LV filling pressures in both groups, while only the isoflurane group showed an increase in heart rate. An increase in end-systolic LV area and decreased fractional area change was present in the halothane group, while an increase in LV end-diastolic area, and similar changes in the mitral Doppler indices (decreases of deceleration rate and time of early diastolic filling), indicating an impairment of early diastolic relaxation, was present in both groups. Isoflurane induced a displacement of the LVED P/A relationship leftwards from the baseline LVED P/A curve. CONCLUSION: Both halothane and isoflurane impair early diastolic relaxation in patients with CAD, when used to control intraoperative surgical stress. In contrast to halothane, isoflurane induced a change in the LVED P/A relationship, suggestive of an increased LVED stiffness.