Fatal and non fatal cardiac arrests related to anesthesia.

PURPOSE: The aim of this study was to assess the incidence and causes of cardiac arrests related to anesthesia. METHODS: All patients undergoing anesthesia over a six year period were included in a prospective study. The cardiac arrests encountered during anesthesia and the first twelve postoperative hours in the PACU or ICU were analysed. For each arrest, partially or totally related to anesthesia, the sequence of events leading to the accident was evaluated. RESULTS: Eleven cardiac arrests related to anesthesia were identified among the 101,769 anesthetic procedures (frequency: 1.1/10,000 [0.44-1.72]). Mortality related to anesthesia was 0.6/10,000 [0.12-1.06]. Age over 84 yr and an ASA physical status > 2 were found to be risk factors of cardiac arrest related to anesthesia. The main causes of anesthesia related cardiac arrest were anesthetic overdose (four cases), hypovolemia (two cases) and hypoxemia due to difficult tracheal intubation (two cases). No cardiac arrests due to alveolar hypoventilation were noted during the postoperative periods in either PACU or ICU. At least one human error was noted in ten of the eleven cardiac arrests cases, due to poor preoperative evaluation in seven. All cardiac arrests totally related to anesthesia were classified as avoidable. CONCLUSION: Efforts must be directed towards improving preoperative patient evaluation. Anesthetic induction doses should be titrated in all ASA 3 and 4 patients. The prediction of difficult tracheal intubation, and if required, the use of awake tracheal intubation techniques, should remain a priority when performing general anesthesia.

[Thrombus of the aortic arch: an unusual pathology in intensive care]. / Le thrombus de la crosse de l'aorte: une pathologie rare en réanimation.

A 54-year-old patient was admitted to the intensive care unit for voluntary drug intoxication with zolipidem (Stilnox), dimenhydrinate (Mercalm), and oestradiol 17 beta (Oromone). Four hours after the admission the patient was comatose. Cerebral computerized tomodensitometry demonstrated multiple zones of ischaemia. Transoesophageal echocardiography was performed 12 hours after the arrival of the patient and revealed a mobile thrombus of the aortic arch. The remainder of the visualized aortic arch did not present atherosclerotic plaque. Secondarily, ischaemia of the right superior limb was diagnosed probably cause by emboli originating in the aortic thrombus appeared. The patient died three days later after her arrival, because of neurologic sequelae of the cerebral embolic events. This clinical case underlines the concept that the diagnosis of drug intoxication must remain a diagnosis of elimination. The thrombosis of the aortic arch is a rare pathology in intensive care units. In the presence of unexplained ischaemic stroke and an peripheral emboli, the thrombosis of the aortic arch should be suspected.

Preoperative screening for von Willebrand disease type 1: low yield and limited ability to predict bleeding.

Type 1 von Willebrand disease (vWd) is the most common hereditary bleeding disorder. The objective of this study was to measure the von Willebrand factor antigen (vWf:Ag) in a large cohort of patients who underwent surgery to assess the role of a new rapid immunoassay in a screening procedure for vWd in preoperative conditions. We studied 832 consecutive patients (540 children, 292 adults) referred to the surgical departments. For each patient we determined the vWf:Ag level with two different assays, an enzyme-linked immunosorbent assay (ELISA)(Asserachrom vWf:Ag; Diagnostica Stago, France) and a rapid immunoassay (Liatest vWf:Ag; Diagnostica Stago). Using the reference test, we found 30 of 832 patients with a vWf:Ag value below the lower limits (21 U/dL to 46 U/dL). The coefficient of correlation between the two tests was 0.77 (P = .001). When receiver operating characteristic curves were used, the cutoff value calculated to detect vWf:Ag defect with the rapid assay was 68.5 U/dL, leading to 0.36% false negatives and 9.7% false positives. Thus the rapid immunoassay appears to be a useful and easy method that is adaptable to urgent situations. Among the 30 patients with low values in ELISA, 8 had personal or familial bleeding history. Repeat blood samples confirmed the diagnosis of vWd in 5 cases, leading to a prevalence of vWd type 1 of 0.6%. However, in our series the absence of severe bleeding complications raises the question of the screening and the management of patients bearing a type 1 Willebrand disease during surgery.

[Severe anaphylactic reactions after administration of rocuronium]. / Accidents anaphylactiques graves après administration de rocuronium.

The authors report four cases of severe anaphylactic reactions (grade III or IV) to rocuronium bromide. In three of them, it was the first contact with a muscle relaxant. In three patients the reaction was mediated by IgE anti-bodies. A cross-reactivity with other muscle relaxants was existing in two cases (suxamethonium, vecuronium and atracurium in one patient, suxamethonium, vecuronium and pancuronium in the other.

[Anaphylactic shock after a test-dose of aprotinin in pediatric orthopedic surgery]. / Choc anaphylactique après dose-test d'aprotinine en chirurgie orthopédique pédiatrique.

A case of severe anaphylactic shock in a 28-month-old child following a testing-dose of aprotinin during major orthopaedic surgery is reported. Two months earlier, aprotinin had been administered during a similar controlateral surgical procedure. The grade III anaphylactic accident required a 48 h treatment in an intensive care unit. The outcome was favourable. The pin-prick tests were positive for aprotinin, substantiating the diagnosis of anaphylactic shock, whereas the test with specific IgE was negative. The value of current diagnostic tools for aprotinin allergy is discussed. The administration of a testing-dose in a patient previously treated with aprotinin cannot be recommended. Considering the risk for allergy, aprotinin should only be administered for recognized indications such as major orthopaedic surgery. Before any readministration of this agent an assessment by an allergist-anaesthetist is essential for determination of the risk-benefit ratio.

Effects of perioperative analgesic technique on the surgical outcome and duration of rehabilitation after major knee surgery.

BACKGROUND: Continuous passive motion after major knee surgery optimizes the functional prognosis but causes severe pain. The authors tested the hypothesis that postoperative analgesic techniques influence surgical outcome and the duration of convalescence. METHODS: Before standardized general anesthesia, 56 adult scheduled for major knee surgery were randomly assigned to one of three groups, each to receive a different postoperative analgesic technique for 72 h: continuous epidural infusion, continuous femoral block, or intravenous patient-controlled morphine (dose, 1 mg; lockout interval, 7 min; maximum dose, 30 mg/4 h). The first two techniques were performed using a solution of 1% lidocaine, 0.03 mg/ml morphine, and 2 microg/ml clonidine administered at 0.1 ml x kg(-1) x h(-1). Pain was assessed at rest and during continuous passive motion using a visual analog scale. The early postoperative maximal amplitude of knee flexion was measured during continuous passive motion at 24 h and 48 h and compared with the target levels prescribed by the surgeon. To evaluate functional outcome, the maximal amplitudes were measured again on postoperative day 5, at hospital discharge (day 7), and at 1- and 3-month follow-up examinations. When the patients left the surgical ward, they were admitted to a rehabilitation center, where their length of stay depended on prospectively determined discharge criteria RESULTS: The continuous epidural infusion and continuous femoral block groups showed significantly lower visual analog scale scores at rest and during continuous passive motion compared with the patient-controlled morphine group. The early postoperative knee mobilization levels in both continuous epidural infusion and continuous femoral block groups were significantly closer to the target levels prescribed by the surgeon than in the patient-controlled morphine group. On postoperative day 7, these values were 90 degrees (60-100 degrees)(median and 25th-75th percentiles) in the continuous epidural infusion group, 90 degrees (60-100 degrees) in the continuous femoral block group, and 80 degrees (60-100 degrees) in the patient-controlled morphine group (P < 0.05). The durations of stay in the rehabilitation center were significantly shorter: 37 days (range, 30-45 days) in the continuous epidural infusion group, 40 days (range, 31-60 days) in the continuous femoral block group, and 50 days (range, 30-80 days) in the patient-controlled morphine group (P < 0.05). Side effects were encountered more frequently in the continuous epidural infusion group. CONCLUSION: Regional analgesic techniques improve early rehabilitation after major knee surgery by effectively controlling pain during continuous passive motion, thereby hastening convalescence.

Causes and prediction of maldistribution during continuous spinal anesthesia with isobaric or hyperbaric bupivacaine.

BACKGROUND: Many cases of cauda equina syndrome after maldistribution of local anesthetics during continuous spinal anesthesia have been reported. In experiments, a caudad route of catheter travel and the use of hyperbaric agents have been shown to induce these limited blocks. The aim of this clinical study was to verify this hypothesis and seek a predictive factor for the maldistribution of bupivacaine. METHOD: Continuous spinal anesthesia via a 19-gauge end port spinal catheter was performed in 80 elderly patients randomly assigned to receive either isobaric or hyperbaric solutions. Successive injections of 2.5 mg bupivacaine were performed at 5-min intervals until a sensory level at or cranial to T8 was obtained. Maldistribution was defined by a sensory level caudal to T12 despite a total dose of 17.5 mg of either isobaric or hyperbaric bupivacaine. After surgery, all catheters were injected with contrast media and examined radiographically. RESULTS: The frequency of maldistribution was not significantly different in the isobaric and hyperbaric groups. A caudally oriented catheter tip was found to be a major cause of maldistribution (P < 10(-5)). A thoracic sensory level could be reached in all patients presenting a limited block by simply changing the baricity of the bupivacaine, the position of the patient, or both. The sensory level obtained 10 min after the first injection of 2.5 mg isobaric or hyperbaric bupivacaine was found to be a predictive factor of maldistribution. CONCLUSIONS: Hyperbaric solutions do not appear to be a clinical factor in the development of limited block. The principle factor causing the maldistribution of bupivacaine is the caudal orientation of the tip of the end-hole catheter rather than its level or the route of catheter travel.

The effects of cervical epidural anesthesia with bupivacaine on pulmonary function in conscious patients.

UNLABELLED: Cervical epidural anesthesia (CEA) can affect diaphragmatic function. We investigated the effects of CEA on the diaphragm muscle performance, breathing pattern, and respiratory drive of 10 healthy patients undergoing hand surgery before and after the administration of 0.25% and 0.375% bupivacaine. The lung volumes and flows, respiratory rate (RR), minute ventilation, respiratory cycle time, occlusion pressure, maximal inspiratory pressure (MIP), and hand grip strength were determined. ETCO2 and SpO2 were continuously monitored. The diaphragmatic excursion was evaluated using ultrasonography. Although CEA allowed painless hand rehabilitation, both 0.25% and 0.375% bupivacaine impaired diaphragmatic excursion, with values decreasing from 5.6 to 4.4 and 3.3 cm (P < 0.05), respectively, during forced sniff maneuvers. In the 0.25% and 0.375% bupivacaine groups, the values of MIP decreased from 74 to 56 and 44 cm H2O, forced vital capacity decreased from 3.8 to 3.2 and 2.8 L, and hand grip strength decreased from 43.3 to 27.8 and 20.5 kg force, respectively (P < 0.05). The tidal volume decreased from 0.8 to 0.6 and 0.5 L in the 0.25% and 0.375% bupivacaine groups, respectively, the RR increased from 14 to 18 breaths/min in both groups, and the occlusion pressure increased from 1.5 to 2.1 and 2.9 cm H2O in the 0.25% and 0.375% bupivacaine groups, respectively (P < 0.05). ETCO2 increased from 35.2 to 38.1 and 39.3 mm Hg in the 0.25% and 0.375% bupivacaine groups, respectively, and SpO2 decreased by 2% +/- 1% in the 0.375% bupivacaine group. CEA affects diaphragmatic function and the resulting lung volumes and MIP values. The observed alterations in breathing pattern and the significant increase in ventilatory drive may be caused by changes in the diaphragmatic muscle tension and an augmented CO2 load. In conclusion, we do not recommend this technique for routine postoperative hand rehabilitation using the studied bupivacaine concentrations. IMPLICATIONS: We studied cervical epidural anesthesia in healthy patients undergoing hand surgery. The technique allowed painless rehabilitation but affected breathing pattern, diaphragmatic function, and respiratory drive. We cannot recommend this technique for routine clinical use.

Comparison of the three-in-one and fascia iliaca compartment blocks in adults: clinical and radiographic analysis.

UNLABELLED: The 3-in-1 (Group 1) and fascia iliaca compartment (Group 2) blocks, two single-injection, anterior approach procedures used to simultaneously block the femoral, obturator, and lateral femoral cutaneous (LFC) nerves, were compared in 100 adults after lower limb surgery. Pain control, sensory and motor blockades, and radiographically visualized spread of local anesthetic solution were studied prospectively. Both approaches provided efficient pain control using 30 mL of 2% lidocaine with 1:200,000 epinephrine and 0.5% bupivacaine and 5 mL of contrast media (iopamidol). Complete lumbar plexus blockade was achieved in 18 (38%) Group 1 and 17 (34%) Group 2 patients (n = 50 patients per group). Sensory block of the femoral, obturator, genitofemoral, and LFC nerves was obtained in 90% and 88%, 52% and 38%, 38% and 34%, and 62% and 90% of the patients in Groups 1 and 2, respectively (P < 0.05). Sensory LFC blockade was obtained more rapidly for the patients in Group 2 (P < 0.05). Concurrent internal and external spread of the local anesthetic solution under the fascia iliaca and between the iliacus and psoas muscles was noted in 62 of the 92 block procedures analyzed radiographically. Isolated external spreads under the fascia iliaca and over the iliacus muscle were noted in 10% and 36% of the patients in Groups 1 and 2, respectively (P < 0.05). The local anesthetic solution reached the lumbar plexus in only five radiographs. We conclude that the fascia iliaca compartment block is more effective than the 3-in-1 block in producing simultaneous blockade of the LFC and femoral nerves in adults. After both procedures, blockade was obtained primarily by the spread of local anesthetic under the fascia iliaca and only rarely by contact with the lumbar plexus. IMPLICATIONS: In adults, the two anterior approaches, 3-in-1 and fascia iliaca compartment blocks, provide effective postoperative analgesia. The fascia iliaca compartment technique provides faster and more consistent simultaneous blockade of the lateral femoral cutaneous and femoral nerves. Sensory block is caused by the spread of local anesthetic solution under the fascia iliaca and only rarely to the lumbar plexus.

Aprotinin decreases blood loss and homologous transfusions in patients undergoing major orthopedic surgery.

BACKGROUND: Major orthopedic surgery can be associated with dramatic blood loss, thereby requiring high-volume homologous transfusions in patients unable to benefit from blood salvage techniques. The effect of aprotinin on blood loss and transfusion requirements during orthopedic surgery for either the resection of malignancies of the removal of infected hardware was prospectively studied. METHODS: Twenty-three patients scheduled for orthopedic surgery of the hip, femur, or pelvis for sepsis or malignant tumors, all under general anesthesia, were randomly allocated to receive during operation, in a blinded manner, either aprotinin administered as a bolus of 1.106 kallikrein inactivation units (KIU) followed by an infusion of 5 x 10(5) KIU/h, or the equivalent volume of saline. The anesthesia and perioperative management, as well as the designated transfusion criteria, were standardized. The total blood loss of each patient was evaluated using intraoperative suction losses, sponge weights, and postoperative volumetric drainage. Homologous transfusion requirements were noted. Hemoglobin and hematocrit measures, as well as coagulation and fibrinolytic pathway explorations, were performed before and after surgery. Deep venous thrombosis prophylaxis was applied, and the incidence of this complication was assessed. RESULTS: Twelve patients received aprotinin. Aprotinin reduced the total blood loss from a median of 5,305 ml (range, 3,000-9,770 ml) to a median of 1,783 ml (range, 1,140-4,955 ml; P < 0.05). A blood loss reduction of 56% during surgery and 68% on discharge from the postanesthesia care unit was observed. Seven units (range, 4-16) of packed erythrocytes were transfused per patient in the placebo group, and 3 (range, 2-5) were transfused in the aprotinin group (P < 0.05). In the aprotinin group, platelet counts were higher, and postoperative prothrombin times and D. Dimer values were lower. The activated partial thromboplastin time values showed no significant difference between the two groups. No side effects were observed in the aprotinin group. A deep venous thrombosis developed in one patient in the placebo group. CONCLUSION: Aprotinin treatment during major orthopedic surgery significantly reduces both blood loss and consequent homologous blood transfusion requirements.

Changes in breathing pattern and respiratory muscle performance parameters during difficult weaning.

OBJECTIVE: This study examined, using noninvasive means, the changes in breathing pattern and inspiratory muscle pressure-time indices during difficult progressive withdrawal of pressure-support ventilation. DESIGN: A prospective analysis of the temporal evolution of several respiratory variables in difficult-to-wean patients. SETTING: A university hospital intensive care unit. PATIENTS: A heterogeneous group of 17 patients receiving prolonged mechanical ventilation. INTERVENTIONS: Daily measurements of breathing pattern and respiratory muscle performance parameters in difficult-to-wean patients. MEASUREMENTS AND MAIN RESULTS: We examined breathing pattern variables, rapid shallow breathing (respiratory rate/tidal volume), tracheal occlusion pressure, maximal inspiratory pressure (P(I)max), and the tension-time index of the inspiratory muscles (TTmus = P(I)/P(I)max x Ti/Ttot) (where Ti/Ttot is inspiratory fraction of the cycle). All measurements were repeated at 24-hr intervals throughout the difficult weaning period. The patients were extubated on satisfying ten of 12 classical weaning criteria. Eleven patients were successfully weaned from mechanical ventilation while six patients were not. Weaning failure was associated with the following: a) longer periods of mechanical ventilation before weaning; b) high values of tracheal occlusion pressure, respiratory rate, minute ventilation, and effective impedance maintained throughout the difficult weaning period; and c) persistent high PaCO2 and intrinsic positive end-expiratory pressure values. As the weaning failure patients' inspiratory muscles confronted an increasing inspiratory load, values of the tension-time index of the inspiratory muscles entered or remained in the fatigue zone. In contrast, weaning success patients normalized their breathing pattern and decreased their tracheal occlusion pressure, effective impedance, and tension-time index values. CONCLUSIONS: Breathing pattern alterations and respiratory muscle performance impairments lead to ventilator dependency after prolonged mechanical ventilation. The measurement of variables such as the noninvasive tracheal occlusion pressure, inspiratory power of breathing, and tension-time index of the inspiratory muscles facilitate the management of difficult-to-wean patients.

[Continuous analgesia with a femoral catheter: plexus or femoral block?]. / Analgésie continue par cathéter fémoral: bloc plexique ou bloc tronculaire fémoral?

OBJECTIVE: To evaluate the spread and quality of sensitive blockade produced by continuous and prolonged use of a femoral catheter inserted for postoperative analgesia. STUDY DESIGN: Prospective non comparative evaluation. PATIENTS: The study included 20 consecutive patients undergoing major knee surgery with postoperative analgesia obtained with a femoral catheter, a technique commonly used in our department. METHODS: Regional analgesia was induced after surgery with a bolus injection of 30 mL of 2% lidocaine with 1:200,000 epinephrine 1 in 200,000, maintained by continuous infusion of 1% lidocaine + morphine 0.03 mg.mL-1 + clonidine 2 micrograms.mL-1 for 48 h. The infusion rate was 0.1 mL.kg-1.h-1. The evaluation was based on: 1) the quality of analgesia at rest, at 30 min, h1, h3, h6, h12, h24 and h48; 2) the sensitive and motor blockade at the same time intervals. RESULTS: A "3 in 1" block was only observed in 50% of patients after the initial bolus via the femoral catheter. During the maintenance of analgesia with a continuous infusion a blockade of the three main nerves of the lumbar plexus occurred in less than 20% of patients after 6 h and was limited to the territory of the femoral nerve in 45 to 50% of patients after 12 to 48 h. In all cases the median values of VAS were below 42 mm. CONCLUSION: In most patients, a local anaesthetic administered continuously via a femoral catheter produces a blockade limited to the femoral nerve. These data do not substantiate the conclusions by those who consider they are producing a continuous "3 in 1" block with this technique. However, it is obviously not essential to produce a sensitive blockade of the three main nerves of the lumbar plexus to obtain an effective analgesia after knee surgery.

Haemodynamic effects of moderate normovolaemic haemodilution in conscious and anaesthetized patients.

We have assessed the haemodynamic effects of moderate normovolaemic haemodilution in ASA I patients, either conscious or during enflurane-fentanyl anaesthesia (10 patients in each group). Cardiac index (CI), stroke index (SI) and ejection fraction (EF) were measured by transthoracic electrical bioimpedance and, in the anaesthesia group, arterial and central venous blood samples were obtained to assess oxygen delivery (DO2), oxygen consumption (VO2) and oxygen extraction ratio (O2ER). In conscious patients, heart rate (HR) remained unchanged as SI, EF and CI increased. When haemodilution was performed during anaesthesia, CI remained stable in spite of a slight increase in SI, as HR decreased. This produced a reduction in DO2 which was compensated for by an increase in O2ER, allowing maintenance of VO2 without alteration in blood lactate concentration.

Spinal anaesthesia in newborns: total and free bupivacaine plasma concentration.

This study was designed to measure total and free bupivacaine (B) after spinal anaesthesia in newborns and to evaluate a possible influence of adrenaline on B absorption. Twenty-two newborns were randomly allocated to receive either plain B (group 1) or adrenaline added to B (group 2) for spinal anaesthesia. A single blood sample was collected ten min after spinal injection. Total B concentration was found 0.31 +/- 0.17 microgram ml-1 in group 1 and 0.25 +/- 0.09 microgram ml-1 in group 2. Bound B concentration was 0.27 +/- 0.17 microgram ml-1 in group 1 and 0.22 +/- 0.09 microgram ml-1 in group 2. No difference was found between the two groups for these parameters. Albumin but not alpha 1-acid-glyco-protein correlated to age and weight, bound B correlated to alpha 1-acid-glyco-protein but not to albumin. Despite the low plasma concentration of binding proteins in newborns, spinal anaesthesia with B does not result in a high level of free drug. Adrenaline does not have any pharmacological advantage in these patients.

Occlusion pressure and its ratio to maximum inspiratory pressure are useful predictors for successful extubation following T-piece weaning trial.

STUDY OBJECTIVE: In most weaning studies, failure group patients are reventilated prior to extubation, thus compromising the evaluation of the applied weaning indices' predictive values. This study determines the usefulness of both standard and recent indices in predicting successful extubation following prolonged mechanical ventilation. DESIGN AND METHODS: Following a successful 20-min T-piece trial, ten traditional weaning criteria, as well as airway occlusion pressure (PO.1), maximal inspiratory pressure (MIP), PO.1/MIP ratio, and shallow breathing (F/VT) were determined in unselected patients undergoing prolonged mechanical ventilation. Having satisfied 8 of 10 classic weaning criteria, 67 patients were extubated after an additional 40 min of successful spontaneous T-piece breathing, and included in the study. After extubation, the tracheal tube resistive pressure (RP) values were measured. RESULTS: Twelve (18%) patients failed extubation. The failure group's average age was significantly greater (69.43 vs 48.43 years). The PO.1, PO.1/MIP, and F/VT values of the success (3.62 +/- 1.35 cm H2O, 0.05 +/- 0.04, and 50 +/- 23 b.min-1.L-1) and failure (7.38 +/- 2.67 cm H2O, 0.14 +/- 0.04, and 69 +/- 25 b.min-1.L-1) groups were significantly different (p < 0.005). The diagnostic accuracies of these indices were, respectively, 88%, 98%, and 73%. The spirometric, gas exchange, and tracheal tube RP values of the two groups showed no significant differences. CONCLUSION: PO.1 and PO.1/MIP ratio provide the best means of predicting extubation success, and they are not influenced by tracheal tube resistance.

Hemodynamic effects of 0.375% versus 0.25% bupivacaine during cervical epidural anesthesia for hand surgery.

BACKGROUND AND OBJECTIVES: Cervical epidural anesthesia with 0.375% or 0.25% bupivacaine plus fentanyl is a reliable technique for surgical restoration of digital motion-after tourniquet release and rehabilitation. The study was designed to assess the hemodynamic effects of this technique in 11 ASA 1 patients. METHODS: The epidural catheter was introduced at the C7-T1 interspace on the day of operation. The volume of 0.375% bupivacaine necessary to block the brachial dermatomes was determined. The day after (day 1), every patient received epidurally the determined volume of 0.375% bupivacaine plus 1 microgram/kg fentanyl (group A). On day 2 the same volume of 0.25% bupivacaine plus 1 microgram/kg fentanyl (group B) was injected. For each patient one or several pairs of injection (A + B) were performed in relation with duration of rehabilitation. Cardiac index, stroke volume index, end diastolic index, ejection fraction, and systemic vascular resistance were studied by thoracic electrical bioimpedance. These parameters, mean arterial pressure and heart rate were recorded before and after injection. Sensory level was assessed by loss of cold sensation. RESULTS: Nineteen paired injections were performed. Mean volume of bupivacaine was 7.1 +/- 2 mL. The caudad sensory level was lower in group A: T7 (T3-L1) versus T6 (T2-T11) in group B. Hemodynamic variables were not different between the 2 groups. Mean arterial pressure cardiac index, heart rate, stroke volume index, and ejection fracture decreased slightly as end diastolic index remained unchanged and systemic vascular resistance increased slightly. No correlation was found between hemodynamic changes and spread of analgesia. CONCLUSIONS: Hemodynamic effects, in ASA 1 patients, are moderate and not dependent on the studied concentration of bupivacaine, indicating that a similar degree of sympathetic block is achieved with 0.375% and 0.25% bupivacaine.