Ignatio Prieto

Bispectral index as an indicator of cerebral hypoperfusion during off-pump coronary artery bypass grafting.

Bradycardia and hypotension are common during off-pump coronary artery bypass grafting (OPCAB). We present a case of possible reversible global cerebral hypoperfusion during distal grafting of the left circumflex coronary artery. The bispectral index (BIS) suddenly decreased from values of 45-50 to 0 during distal grafting. Neurologic evaluation after immediate tracheal extubation in the operating room was normal and the 58 yr old patient did not suffer any neurologic sequelae. Postoperative recovery was uneventful and the patient was discharged 5 days after surgery. Cerebral hypoperfusion is a possible complication during OPCAB. BIS monitoring in OPCAB could be an indicator of cerebral hypoperfusion.

Ultra-fast-track anesthesia in off-pump coronary artery bypass grafting: a prospective audit comparing opioid-based anesthesia vs thoracic epidural-based anesthesia.

PurposeTo examine the feasibility of immediate extubation after off-pump coronary artery bypass grafting (OPCAB) using opioid based analgesia or high thoracic epidural analgesia (TEA) and compare postoperative analgesia with continuous TEA vs patient-controlled analgesia (PCA).MethodsOne hundred consecutive patients undergoing OPCAB were included in this prospective audit. After induction of anesthesia using fentanyl 2 to 5 μg·kg−1, propofol 1 to 2 mg·kg−1 and endotracheal intubation facilitated by rocuronium, anesthesia was maintained using sevoflurane titrated according to bispectral index monitoring. Perioperative analgesia was provided by TEA (n = 63) at the T3/T4 interspace or T4/T5 interspace using bupivacaine 0.125% 8 to 14 mL·hr−1 and repetitive boluses of bupivacaine 0.25% during surgery. In patients who were fully anticoagulated or refused TEA, perioperative analgesia was achieved by iv fentanyl boluses (up to 15 μg·kg−1) and remifentanil 0.1 to 0.2 μg·kg−1·min−1, followed by morphine PCA after surgery (n = 37). Maintenance of body temperature was achieved by a heated operating room and forced-air warming blankets.ResultsNinety-five patients were extubated within 25 min after surgery (PCA,n = 33; TEA,n = 62). Five patients were not extubated immediately because their core temperature was lower than 35°C. One patient was re-intubated because of agitation (TEA group); one was re-intubated because of severe pain and morphine-induced respiratory depression (PCA group). Pain scores were low after surgery, with pain scores in the TEA group being significantly lower immediately, at six hours, 24 hr and 48 hr after surgery (P < 0.05).ConclusionImmediate extubation is possible after OPCAB using either opioid-based analgesia or TEA. TEA provides significantly lower pain scores after surgery in comparison to morphine PCA.RésuméObjectifVérifier la faisabilité de l’extubation immédiatement après un pontage aortocoronarien à cœur battant (PACCB) en utilisant une analgésie avec opioïdes ou une analgésie péridurale thoracique (APT), et comparer l’analgésie postopératoire avec APT continue ou analgésie auto-contrôlée (AAC).MéthodeCent patients consécutifs devant subir un PACCB ont été inclus dans un audit prospectif. Après l’induction de l’anesthésie avec 2 à 5 μg·kg−1 de fentanyl, 1 à 2 mg·kg−1 de propofol et l’intubation endotrachéale facilitée par du rocuronium, l’anesthésie a été maintenue avec du sévoflurane ajusté selon le monitorage de l’index bispectral. L’analgésie périopératoire a été fournie par l’APT (n = 63) dans l’espace intervertébral T3/T4 ou T4/T5 avec de la bupivacaïne à 0,125 % à raison de 8 à 14 mL·h−1 et de bolus répétés de bupivacaïne à 0,25 % pendant l’opération. Chez les patients traités aux anticoagulants ou qui refusaient l’APT, l’analgésie périopératoire a été réalisée par des bolus iv de fentanyl (jusqu’à 15 μg·kg−1) et de 0,1 à 0,2 μg·kg−1 ·min−1 de rémifentanil, suivi de morphine en AAC postopératoire (n = 37). La température corporelle a été maintenue dans une salle d’opération chauffée et par des couvertures chauffantes à air forcé.RésultatsOn a pu extuber 95 patients pendant les 25 premières minutes postopératoires (AAC, n = 33; APT, n = 62). Cinq patients n’ont pu être extubés immédiatement, étant donné leur température centrale plus basse que 35 °C. Deux patients ont été ré-intubés : l’un, du groupe d’APT, pour agitation, l’autre, du groupe d’AAC, à cause de douleurs intenses et de dépression respiratoire induite par la morphine. Les scores de douleur postopératoires ont été faibles, ceux du groupe d’APT étant significativement plus bas immédiatement après, puis à 6, 24 et 48 h postopératoire (P < 0,05).ConclusionL’extubation immédiate est possible après le PACCB en utilisant soit une analgésie avec opioïdes, soit une APT. L’APT, comparée à l’AAC avec morphine, produit des scores de douleurs postopératoires significativement plus bas.

Upper Extremity Vein Graft for Aortocoronary Bypass

Twenty-four autologous vein grafts taken from the upper extremities were used in 13 patients undergoing aortocoronary bypass procedures. All of these patients had had previous bilateral saphenous vein stripping. Clinical follow-up between 3 months and 6 1/2 years is reported. Ten patients were recatheterized. There was neither operative mortality nor appreciable morbidity. All the patients are alive and well at the present time. Eleven out of 13 were in New York Heart Association (NYHA) Class I 3 months after operation. Nine patent grafts out of 10 were seen during recatheterization in 6 patients studied less than 9 months after operation. In a subgroup of 5 patients followed for more than 1 year, 2 are now in NYHA Functional Class I, 2 in Class II, and 1 in Class III. Graft patency had been determined in 4 of these patients. Five grafts out of 8 were patent, 2 of them with gross abnormalities. In conclusion, we have some reservations about the long-term fate of these grafts.

Awake cardiac surgery using a novel anesthetic technique.

Objectif Decrire les premiers cas publies de cardiochirurgie vigile au Canada. De plus, presenter une nouvelle technique anesthesique qui est une combinaison de bloc femoral et ďanesthesie peridurale thoracique haute.

Heart Valve Replacement with the Björk-Shiley Monostrut Valve: Early Results of a Multicenter Clinical Investigation

To evaluate the clinical performance of the Björk-Shiley Monostrut prosthesis, five centers combined their early experience. Between May, 1982, and June, 1985, 537 prostheses were implanted in 486 patients at these centers: 246 patients had aortic valve replacement (AVR), 163 underwent mitral valve replacement (MVR), and 47 had double-valve replacement (DVR). Thirty patients underwent other, more complex procedures. Concomitant cardiac procedures were performed in altogether 25%. Overall hospital (30 days) mortality was 5.1% (3.6% for AVR, 4.3% for MVR, 8.3% for DVR, and 16.6% for other procedures). The patients were followed up at 6- to 9-month intervals from 6 to 48 months (mean follow-up, 33 months). Follow-up was 99.6% complete. Late mortality was 7.2%. The three-year survival rate was 91.0% for AVR, 92.3% for MVR, and 76.2% for DVR. There was no structural failure of the prosthesis. No instances of valve thrombosis and fatal thromboembolism occurred in anticoagulated patients. The three-year incidence of freedom from thromboembolic events (including TIA) was 89.8% for AVR, 94.9% for MVR, and 90.2% for DVR. Preoperative and postoperative data for the assessment of mechanical hemolysis was available in 60% of the patients. The degree of mechanical hemolysis was low and did not change with time. Although the follow-up is still short, the Björk-Shiley Monostrut prosthesis appears to represent an improvement over previous Björk-Shiley models, particularly with regard to durability.

Une nouvelle technique anesthésique pour la chirurgie cardiaque vigile

Objectif Decrire les premiers cas publies de cardiochirurgie vigile au Canada. De plus, presenter une nouvelle technique anesthesique qui est une combinaison de bloc femoral et ďanesthesie peridurale thoracique haute.

Sevoflurane causes less arrhythmias than desflurane after off-pump coronary artery bypass grafting: a pilot study.

BACKGROUND Volatile anesthetics provide myocardial protection during cardiac surgery. Sevoflurane and desflurane are both efficient agents that allow immediate extubation after off-pump coronary artery bypass grafting (OPCABG). This study compared the incidence of arrhythmias after OPCABG with the two agents. MATERIALS AND METHODS Forty patients undergoing OPCABG with immediate extubation and perioperative high thoracic analgesia were included in this controlled, double-blind study; anesthesia was either provided using 1 MAC of sevoflurane (SEVO-group) or desflurane (DES-group). Monitoring of perioperative arrhythmias was provided by continuous monitoring of the EKG up to 72 hours after surgery, and routine EKG monitoring once every day, until time of discharge. Patient data, perioperative arrhythmias, and myocardial protection (troponin I, CK, CK-MB-ratio, and transesophageal echocardiography examinations) were compared using t-test, Fishers exact test or two-way analysis of variance for repeated measurements; P < 0.05. RESULTS Patient data and surgery-related data were similar between the two groups; all the patients were successfully extubated immediately after surgery, with similar emergence times. Supraventricular tachycardia occurred only in the DES-group (5 of 20 patients), atrial fibrillation was significantly more frequent in the DES group versus SEVO-group, at five out of 20 versus one out of 20 patients, respectively. Myocardial protection was equally achieved in both groups. DISCUSSION Ultra-fast track anesthesia using sevoflurane seems more advantageous than desflurane for anesthesia, for OPCABG, as it is associated with significantly less atrial fibrillation or supraventricular arrhythmias after surgery.

Regional anesthesia in cardiac surgery and immediate extubation after cardiac surgery: a different view

To the Editor: We read with great interest the editorial by Dr. Cheng.1 Dr. Cheng questions the economic benefit of immediate extubation after cardiac surgery in our prospective audit.2 He states that the patients being transferred to the postanesthesia care unit (PACU) immediately after extubation needed a nurse cover of a ratio of 1:1 and mentions that this is more intensive than nurse : patient ratio in patients who arrive in the intensive care unit (ICU) intubated. We would therefore like to stress the fact that in our ICU, patients arriving intubated/ventilated from the operating room (OR) are dealt with on a nurse : patient ratio of 1:1, as is the case in the PACU immediately after surgery when the patients arrive extubated from the OR. Therefore, they do not need more nursing care than patients still intubated after cardiac surgery. Dr. Cheng states that thoracic epidural analgesia (TEA) has been reported to provide no improvement in postoperative mobilization, spirometry function and hospital length of stay, based on one study.3 Scott et al.4 conducted a prospective, randomized and controlled study evaluating the incidence of organ complications in 420 patients undergoing routine coronary artery bypass grafting with or without TEA, and found a significantly lower rate of respiratory tract infections, and better pulmonary function as measured in maximal inspiratory lung volume in patients with TEA. Liem et al.5 in another, smaller study, found a significantly higher postoperative PaO2 whenever TEA was used. The authors are surprised by Dr. Cheng’s statement that complications after TEA include pruritus, nausea and vomiting and urinary retention. Pruritus, nausea and vomiting might occur whenever opioids are added to TEA, but are not related to TEA itself in more than 400 cases of TEA with plain bupivacaine in our hospital setting, no patient experienced pruritus or nausea and vomiting related to TEA. Urinary retention might be a complication of lumbar TEA, but seems rather rare with high TEA. High TEA might actually improve renal function,6 or at least not be different from general anesthesia.7 Large multicentre prospective studies are required to further prove the benefits of TEA in cardiac surgery.

Comparison of Three Different Epidural Solutions in Cardiac Surgery for Stress Protection

Background: Different solutions are possible for thoracic epidural analgesia in cardiac surgery. So far, local an- esthetics alone or in combination with either clonidine or opioids have been used. Aims: To determine the stress protection provided by different epidural solutions throughout cardiac surgery. Study Design: A randomized, prospective, double blind study in patients undergoing off-pump coronary artery bypass grafting (OPCAB), randomized in three different groups. Thoracic epidural analgesia was installed more than 1 h before application of heparin at levels of T2 to T4; analgesia was provided by 8 ml of bupivacaine 0.25% 15 min prior to surgery and extubation, and 10 ml/h during and up to 72 h after surgery using one of the following regimens: bupivacaine 0.125% solely, bupivacaine 0.125% with fentanyl 3 � g/mL or bupivacaine 0.125% with clonidine 0.6 � g/mL. Patients were block- randomized for one of the three treatments. Cortisol and glucose values were determined before surgery, at extubation and 1h and 3h after surgery. Pain scores were assessed up to 48 h after surgery. Hemodynamic stability was also recorded in form of heart rate, systolic and diastolic blood pressure. Multi-comparison ANOVA and Chi-square test were used to compare the data, presented as mean (SD) or median (25 th and 75 th percentile), P < 0.05. Study Setting: A cardiac surgery unit at a tertiary university hospital. Participants: Forty-two patients undergoing OPCAB were enrolled. Main Results: All patient data as well hemodynamic stability were not different between the three groups. All patients were successfully extubated in theatre immediately after surgery. Pain control was good and not significantly different be- tween the groups. Mean glucose concentrations ± SD before surgery and (significantly higher) 3h after surgery were 5.4 ± 1.0 mmol l -1 and 8.4 ± 1.6 mmol l -1 for bupivacaine alone, 5.2 ± 0.5 mmol l -1 and 8.5 ± 2.2 mmol l -1 for bupivacaine plus fentanyl and 5.5 ± 1.6 mmol l -1 and 9.5 ± 2.1mmol l -1 for bupivacaine and clonidine, respectively. The mean cortisol val- ues ± SD in the pre-operative period and 3h after surgery were 413 ± 162 nmol l -1 and 562 ± 173 nmol l -1 for bupivacaine alone, 393 ± 107 nmol l -1 and 581 ± 265 nmol l -1 for bupivacaine and fentanyl and 409 ± 159 nmol l -1 and 570 ± 160 nmol l -1 for bupivacaine and clonidine, respectively. There were no significant differences between the groups. Conclusions: We conclude that short-term stress protection with TEA is equally effective with solely bupivacaine, bupivacaine with fentanyl or clonidine.

Desflurane causes more atrial fibrillation and tachycardia after off-pump aorto-coronary bypass grafting (OPCAB) than sevoflurane

METHODS. Forty patients undergoing OPCAB with TEA and ultra-fast-track anesthesia were randomized in this pilot study in two groups of 20 patients. Anesthesia was maintained with either 1 MAC of sevoflurane or 1 MAC of desflurane. Continuous ECGmonitoring for the detection of arrhythmias was performed during and up to 72 h after surgery, Troponine-T, CK-MB, regional wall motion abnormalities and ejection fraction, time to extubation, respiratory functions and hemodynamic stability were compared using t-test or Chi-square test. P < 0.05.