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H Litvan

Publications and source records attributed to H Litvan.

At least 19 recordsLinked to original sources
PubMed2004

Pitfalls and challenges when assessing the depth of hypnosis during general anaesthesia by clinical signs and electronic indices.

The objective of this article was to review the present methods used for validating the depth of hypnosis. We introduce three concepts, the real depth of hypnosis (DHreal), the observed depth of hypnosis (DHobs), and the electronic indices of depth of hypnosis (DHel-ind). The DHreal is the real state of hypnosis that the patient has in a given moment during the general anaesthesia. The DHobs is the subjective assessment of the anaesthesiologist based on clinical signs. The DHel-ind is any estimation of the depth of hypnosis given by an electronic device. The three entities DHreal, DHobs and DHel-ind should in the ideal situation be identical. However, this is rarely the case. The correlation between the DHobs and the DHel-ind can be affected by a number of factors such as the stimuli used for the assessment of the level of consciousness or the administration of analgesic agents or neuro muscular blocking agents. Opioids, for example, can block the response to tactile and noxious stimuli, and even the response to verbal command could vanish, hence deeming the patient in a lower depth of hypnosis than the real patient state. The DHel-ind can be disturbed by the presence of facial muscular activity. In conclusion, although several monitors and clinical scoring scales are available to assess the depth of hypnosis during general anaesthesia, care should be taken when interpreting their results.

Acoustic Stimulation↗
PubMed2002

Comparison of auditory evoked potentials and the A-line ARX Index for monitoring the hypnotic level during sevoflurane and propofol induction.

BACKGROUND: Extraction of the middle latency auditory evoked potentials (AEP) by an auto regressive model with exogenous input (ARX) enables extraction of the AEP within 1.7 s. In this way, the depth of hypnosis can be monitored at almost real-time. However, the identification and the interpretation of the appropriate signals of the AEP could be difficult to perform during the anesthesia procedure. This problem was addressed by defining an index which reflected the peak amplitudes and latencies of the AEP, developed to improve the clinical interpretation of the AEP. This index was defined as the A-line Arx Index (AAI). METHODS: The AEP and AAI were compared with the Modified Observers Assessment of Alertness and Sedation Scale (MOAAS) in 24 patients scheduled for cardiac surgery, anesthetized with propofol or sevoflurane. RESULTS: When comparing the AEP peak latencies and amplitudes and the AAI, measured at MOAAS level 5 and level 1, significant differences were achieved. (mean(SD) Nb latency: MOAAS 5 51.1 (7.3) ms vs. MOAAS 1: 68.6 (8.1) ms; AAI: MOAAS 5 74.9 (13.3) vs. MOAAS 1 20.7 (4.7)). Among the recorded parameters, the AAI was the best predictor of the awake/anesthetized states. CONCLUSION: We conclude that both the AAI values and the AEP peak latencies and amplitudes correlated well with the MOAAS levels 5 (awake) and 1 (anesthetized).

Anesthesia↗
PubMed2000

Platelet function during cardiopulmonary bypass not changed by two different doses of aprotinin.

BACKGROUND AND OBJECTIVE: Bleeding is one of the major complications of cardiopulmonary bypass (CBP) during cardiac surgery. A platelet function defect seems to be the main cause of the hemostatic problems associated with CBP. Controversial results have been reported concerning the possible protective mechanism of action of aprotinin on platelets. DESIGN AND METHODS: In this study we investigated the effect of two different dosages of aprotinin (high and pump-prime-only dose) on platelet reactivity in vitro and adhesion, activation and aggregation receptors on the platelet surface. RESULTS: The results obtained from 53 patients undergoing CBP showed a significantly deficient platelet aggregation in response to agonist in all groups without differences between aprotinin treated or not treated patients. No changes in platelet surface expression of glycoprotein (GP) IIb-IIIa, GPIb, GPIV and P-selectin, were observed during CBP between patients treated with aprotinin or not. INTERPRETATION AND CONCLUSIONS: These data suggest that inadequate platelet function induced by CBP is not a defect intrinsic to the platelet. We conclude that the hemostatic effect of aprotinin, regardless of the dose employed, is not mediated by protection of platelet function.

Adult↗
PubMed2000

[Use of the anesthetic cream EMLA in arterial punction].

INTRODUCTION: Arterial puncture is a painful procedure requiring prior local anesthesia. Various products are available for pain relief, among them EMLA anesthetic cream. OBJECTIVE: To compare pain from simple puncture of the radial artery performed with or without application of EMLA anesthetic cream and after infiltration of mepivacaine. PATIENTS AND METHODS: A prospective, random double-blind study of 153 patients in three groups: group A, 51 patients who were applied 1 g of EMLA cream; group B, 52 patients who were applied 1 g of placebo cream; and group C, 50 patients who received infiltration of 0.2 ml of 1% mepivacaine. Pain was assessed on a 10 cm visual analog scale (0, absence of pain; 10, greatest imaginable pain). RESULTS: Pain intensity reported by the patients was 2.6 +/- 1.8 in group A, 2.9 +/- 1.8 in group B and 1.6 +/- 1.8 in group C. The results for group C were statistically different from those for groups A and B. The difference between groups A (EMLA) and B (placebo), however, was not statistically significant. CONCLUSIONS: Mepivacaine infiltration is the more effective method for minimizing pain from puncture of the radial artery. EMLA anesthetic cream is not effective against pain caused by this procedure.

Anesthesia, Local↗
PubMed2000

The effect of two different doses of aprotinin on hemostasis in cardiopulmonary bypass surgery: similar transfusion requirements and blood loss.

BACKGROUND AND OBJECTIVES: Various dosages of aprotinin have proven to be effective in reducing blood loss and allogeneic transfusion requirements in cardiopulmonary bypass surgery, despite the controversy surrounding the precise hemostatic mechanisms of this drug. The aim of our prospective, randomized, double-blind study was to assess differences in blood loss and transfusion requirements and the effect of two dosages of aprotinin on hemostatic activation. DESIGN AND METHODS: Patients undergoing coronary artery bypass grafting received high-dose aprotinin (n=28), pump-prime-only (PPO) aprotinin (n=28), or placebo (n=28). RESULTS: The high-dose and the PPO groups had a significantly lower blood loss (985 mL [95%CI 845-1,102] and 1,255 mL, [95% CI 1,025-1,406], respectively) than the placebo group (1,416 mL, 95%CI 1,248-1,612]. Transfusion requirements were lower in the aprotinin-treated groups than in the patients receiving placebo (21 units and 15 units in the high and low-dose groups vs 59 units in placebo group). As far as concerns parameters of thrombin generation, the aprotinin groups showed a significant reduction of F1+2 prothrombin fragment but not of thrombin-antithrombin complexes. There were higher levels of natural anticoagulants, i.e. antithrombin, protein C and protein S, in the high-dose aprotinin group. As regards fibrinolysis parameters, D-dimer was lower in the aprotinin groups, and the levels of alpha2-antiplasmin and plasmin-alpha2-antiplasmin complexes were raised. In summary, both dosages of aprotinin were equally effective in reducing blood loss and transfusion requirements. There was a lower activation of coagulation and fibrinolysis in cardiopulmonary bypass patients treated with aprotinin: the levels of natural anticoagulants were less decreased in the high-dose group. No differences in thrombotic complications were observed between aprotinin groups. INTERPRETATION AND CONCLUSIONS: Our study shows that both dosages of aprotinin are safe and effective in reducing transfusion requirements. Considering the difference in cost of using a low-dose or high-dose schedule, the former should be recommended for patients undergoing cardiopulmonary bypass surgery.

Adult↗
PubMed2000

[Comparison of an auditory evoked potentials index and a bispectral index versus clinical signs for determining the depth of anesthesia produced by propofol or sevoflurane].

OBJECTIVES: To evaluate an anesthetic depth index (ADI) obtained from auditory evoked potentials and a bispectral EEG index (BIS) in comparison with clinical assessment of anesthetic depth using the modified observer's assessment of awareness/sedation scale (MOAA/SS), for induction of anesthesia with propofol or sevoflurane as the only agent. PATIENTS AND METHODS: The ADI and BIS were recorded simultaneously in this prospective study and compared to the MOAA/SS during the anesthetic induction of 26 adults undergoing elective heart surgery. Assignment of patients to two groups was random. Group A (n = 13) patients were induced with propofol (target dose 5 micrograms.ml-1 in 5 min). Induction in group B (n = 13) was with sevoflurane (8% tidal volume). A scheme of awake-sleeping-awake-sleeping was followed. The means of the two indexes were compared (Mann-Whitney test) one minute before the patient slept (awake) and one minute later (sleeping), and the evolution of the indexes was compared during awake/sleep and sleep/awake phase changes and while the patients were in a stable sleep phase. The sensitivity and specificity of each index was analyzed in function of the MOAA/SS. We also analyzed the time elapsing from the moment the patient fell asleep (MOAA/SS 2) until the two indexes reached published reference values (ADI = 38, BIS = 60). RESULTS: After induction with propofol (group A) the ADI fell to 29.2 +/- 11.7 and the BIS fell to 63.5 +/- 13.4. After induction with sevoflurane (group B) the ADI fell to 33.8 +/- 14.9 and the BIS to 66.8 +/- 15. The ADI value that best discriminated between arousal and sleeping (sensitivity 100%) was 38; the BIS value that best discriminated was 60. The responses to sound in decibels (dB) during "awake/sleeping" and "sleeping/awake" phases were, respectively, -3.8 dB and -4.5 dB for the ADI and -1.5 dB and -0.8 dB for the BIS. With the patient in stable sleep, response to the two indexes was at -0.79 dB. In group A, the ADI detected MOAA/SS 2 significantly earlier (ADI 13.1 +/- 30 s; BIS 56 +/- 36 s; p < 0.05). No patient reported remembering the study period. CONCLUSIONS: Monitoring anesthetic depth with the ADI or BIS was technically easy and effective for detecting whether patients were awake or sleeping. The ADI response was faster and identified awake/sleeping and sleeping/awake phase changes better than did the BIS.

Adult↗
PubMed1999

Ministernotomy versus median sternotomy for aortic valve replacement: a prospective, randomized study.

BACKGROUND: Minimally invasive aortic valve replacement reduces surgical trauma and, supposedly, postoperative pain, blood loss, and length of stay. A prospective, randomized study was designed to prove these theoretical advantages. METHODS: Forty patients undergoing isolated, elective aortic valve replacement were randomized into two equal groups. Patients in group M underwent aortic valve replacement through a ministernotomy (reversed L or reversed C). In group S, a median sternotomy was used. The anesthetic and surgical protocol was identical for both groups. Pain was evaluated on a daily basis. Pulmonary function tests were performed preoperatively and before hospital discharge in all patients. RESULTS: There were two deaths in each group. Cross-clamp time was longer in group M: 70 +/- 19 minutes versus 51 +/- 13 minutes in group S (p = 0.005). There were no statistically significant differences between groups M and S in pump time (95 +/- 20 minutes versus 83 +/- 19 minutes), extubation time (9.9 hours in both groups), chest drainage (479 +/- 274 mL/L 24 hours versus 355 +/- 159 mL/24 hours), transfusion requirements (27% in both groups), pain evaluation (1.34 +/- 1.3 versus 2.15 +/- 1.5), length of stay (6.2 +/- 2.3 days versus 6.3 +/- 2.5 days), and cosmetic appraisal. Forced vital capacity decreased 26% from preoperative reference values in group M and 33% in group S (p = not significant). Forced expiratory volume in 1 second decreased 22% and 35%, respectively (p = not significant). CONCLUSIONS: This study has failed to prove the theoretical advantages of minimally invasive aortic valve replacement. With this technique, cross-clamp time is longer than with a median sternotomy.

Adult↗
PubMed1999

[Impossibility of intubation due to angioedema secondary to an angiotensin-converting enzyme inhibitor].

Angioedema secondary to treatment of one year's duration with angiotensin converting enzyme inhibitor (ACEI) (lisinopril) in a 56-year-old man scheduled for elective cardiac surgery led unexpectedly to impossible intubation. Surgical access (tracheostomy) was required when airway control was threatened. We review the clinical course, etiology and treatment of angioedema secondary to ACEI therapy. This is a life threatening complication which, though rare, is becoming increasingly frequent with increased use of such drugs.

Angioedema↗
PubMed1999

Pulmonary function following aortic valve replacement: a comparison between ministernotomy and median sternotomy.

BACKGROUND AND AIM OF THE STUDY: Minimally invasive aortic valve replacement (AVR) has several theoretical advantages over standard median sternotomy, but the effects of these techniques on postoperative pulmonary function have not been determined. METHODS: Twenty-six patients undergoing AVR through either a ministernotomy (group M; n = 12) or a median sternotomy (group S; n = 14) underwent pulmonary function tests. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), PaO2 and PaCO2 were determined preoperatively and before hospital discharge (at a mean of five days). Data regarding time to extubation, degree of pain and opening of the pleura were collected prospectively. Both groups had similar preoperative characteristics. RESULTS: There was a significant decrease in FVC, FEVJ, PaO2 and PaCO2 during the postoperative period in all patients, though differences between the groups were not significant. Patients in group M referred less pain than those in group S. In this group, the fall in FVC and FEV1 correlated with the degree of pain, while preoperative FVC correlated with early extubation. Pleurotomy did not affect pulmonary function or pain. CONCLUSION: FVC, FEV1, PaO2 and PaCO2 are reduced significantly following AVR, but a minimally invasive approach does not prevent postoperative pulmonary dysfunction.

Aged↗
PubMed1995

Aprotinin versus desmopressin for patients undergoing operations with cardiopulmonary bypass. A double-blind placebo-controlled study.

BACKGROUND: Aprotinin reduces blood loss in operations done with cardiopulmonary bypass, whereas the use of desmopressin remains controversial. We compared aprotinin, desmopressin, and placebo in a double-blind, randomized trial to evaluate bleeding and transfusion requirements. METHODS AND RESULTS: One hundred forty-nine patients (48 received aprotinin, 50 desmopressin, 51 placebo) were included. Blood loss and transfusion requirements were recorded and levels of Factor VIII coagulant activity, von Willebrand's factor, thrombin-antithrombin complexes, and D-dimer were measured. Overall blood loss was 195 +/- 146 ml/m2 in the aprotinin group, 400 +/- 192 ml/m2 in the desmopressin group, and 489 +/- 361 ml/m2 in the placebo group (95% confidence intervals: difference between desmopressin and aprotinin 98 to 312 ml/m2, p < 0.001; difference between placebo and aprotinin 190 to 398 ml/m2, p < 0.001). Twenty-six percent of patients treated with aprotinin, 66% of those treated with desmopressin, and 56% of those treated with placebo were given transfusion (95% confidence intervals: difference between aprotinin versus placebo plus desmopressin 51% to 71%, p < 0.001). Fibrinolytic activation throughout cardiopulmonary bypass was markedly higher with placebo or desmopressin administration. D-dimer level correlated with overall blood loss in patients receiving desmopressin or placebo, but not in those receiving aprotinin. CONCLUSION: Aprotinin administration reduces blood loss and transfusion requirements in cardiopulmonary bypass. This benefit may be explained by a lower activation of fibrinolysis.

Antithrombin III↗