[Prevention, diagnosis and treatment of bleeding in cardiac surgery]. / Prevención, diagnóstico y tratamiento de la hemorragia en cirugía cardiaca.

Patients undergoing cardiac surgery are at high risk of bleeding and transfusion. This risk has increased in recent years and is associated with increased morbidity and mortality. Moreover, despite being one of the most common complications associated with this surgery, there remains a large variability in its management between institutions. Implementation of algorithms for coagulation management has been shown to reduce transfusion requirements and therefore it seems essential to establish protocols that include preventive measures, effective mechanisms for diagnosis and treatment algorithms. On the other hand, the emergence of new drugs and the use of point of care coagulation monitoring systems, is changing our diagnostic and therapeutic options. This paper reviews several aspects related to the causes, diagnosis and treatment of bleeding associated with cardiac surgery and presents an algorithm for its management.

Incidence and predictors of major perioperative adverse cardiac and cerebrovascular events in non-cardiac surgery.

BACKGROUND: Major adverse cardiac and cerebrovascular events (MACCE) represent the most common cause of serious perioperative morbidity and mortality. Our aim was to identify risk factors for MACCE in a broad surgical population with intermediate-to-high surgery-specific risk and to build and validate a model to predict the risk of MACCE. METHODS: A prospective, multicentre study of patients undergoing surgical procedures under general or regional anaesthesia in 23 hospitals. The main outcome was the occurrence of at least one perioperative MACCE, defined as any of the following complications from admittance to discharge: cardiac death, cerebrovascular death, non-fatal cardiac arrest, acute myocardial infarction, congestive heart failure, new cardiac arrhythmia, angina, or stroke. The MACCE predictive index was based on ß-coefficients and validated in an external data set. RESULTS: Of 3387 patients recruited, 146 (4.3%) developed at least one MACCE. The regression model identified seven independent risk factors for MACCE: history of coronary artery disease, history of chronic congestive heart failure, chronic kidney disease, history of cerebrovascular disease, preoperative abnormal ECG, intraoperative hypotension, and blood transfusion. The area under the receiver-operating characteristic curve was 75.9% (95% confidence interval, 71.2-80.6%). CONCLUSIONS: The risk score based on seven objective and easily assessed factors can accurately predict MACCE occurrence after non-cardiac surgery in a population at intermediate-to-high surgery-specific risk.

Acute kidney injury after cardiac surgery: prevalence, impact and management challenges.

Acute kidney injury (AKI) is a major medical problem that is of particular concern after cardiac surgery. Perioperative AKI is independently associated with an increase in short-term morbidity, costs of treatment, and long-term mortality. In this review, we explore the definition of cardiac surgery-associated acute kidney injury (CSA-AKI) and identify diverse mechanisms and risk factors contributing to the renal insult. Current theories of the pathophysiology of CSA-AKI and description of its clinical course will be addressed in this review. Data on the most promising renal protective strategies in cardiac surgery, from well-designed studies, will be scrutinized. Furthermore, diagnostic tools such as novel biomarkers of AKI and their potential utility will be discussed.

[Two cases of early postoperative massive pulmonary thromboembolism after gastric bypass surgery]. / Dos casos de tromboembolismo pulmonar masivo precoz en el postoperatorio de cirugía bariáitrica.

Pulmonary thromboembolism in the early postoperative period is rare. We present 2 cases of massive embolism that occurred soon after gastric bypass surgery. The first patient was a 32-year-old man, a smoker with a body mass index (BMI) of 52 kg/m2, obstructive sleep apnea-hypopnea syndrome and venous insufficiency in the lower extremities. Fatal cardiorespiratory arrest occurred 22 hours after surgery. Autopsy confirmed massive pulmonary thromboembolism. The second patient was a 48-year-old woman with a BMI of 40 kg/m2 who had undergone abdominal hysterectomy 2 months earlier. She survived cardiorespiratory arrest occurring 11 hours after surgery. There were no sequelae. The diagnosis of pulmonary thromboembolism was confirmed by transesophageal echocardiography. These patients undoubtedly had asymptomatic deep vein thrombosis before the operations. Prevention of pulmonary embolism is essential in high risk patients. The prophylactic measures usually applied are administration of low molecular weight heparin to prevent thrombosis, early ambulation, and the use of elastic compression stockings or intermittent pneumatic compression.

[Postoperative patient-controlled analgesia is more effective with epidural methadone than with intravenous methadone in thoracic surgery]. / La analgesia postoperatoria controlada por el paciente es más efectiva con metadona epidural que con metadona endovenosa en la cirugía torácica.

OBJECTIVE: To compare the efficacy and side effects of epidural and intravenous methadone for postoperative patient-controlled analgesia (PCA) after thoracic surgery. PATIENTS AND METHODS: A randomized, single-blind trial enrolling 30 patients distributed in 2 groups to receive intravenous methadone (ivPCA group) or epidural methadone (epPCA group). Patients in both groups were administered a loading dose of 0.05 mg.kg-1 followed by infusion of 0.5 mg.h-1. The patients could self-dose 0.5 mg with a lock-out interval of 10 minutes and a maximum of 4 doses per hour. Patient characteristics, type and duration of surgery and fentanyl dose were recorded. Pain was assessed on a visual analog scale (VAS). Level of sedation, respiratory rate and occurrence of nausea, vomiting and pruritus were also recorded over the first 24 hours. RESULTS: The 2 groups were comparable. Pain was greater in the ivPCA group than in the epPCA group in the second hour (VAS 3.93 +/- 1.9 and 2.4 +/- 1.65, respectively; P < .05) and the third hour (VAS 3.57 +/- 1.65 and 1.5 +/- 1.16, respectively; P < .05). The total dose of methadone administered was 25.34 +/- 5.65 mg in the ivPCA group and 18.82 +/- 3.52 mg in the epPCA group (P < .002). There were no significant differences in side effects. CONCLUSIONS: The results suggest that epidural methadone has an intrinsic spinal effect regardless of whether or not there is extra-spinal action arising from syste mic absorption. Epidural methadone provides a more adequate analgesic effect in less time and at a lower dose. Both approaches provide good postoperative analgesia with few side effects.

[Gas embolism secondary to intraoperative use of hydrogen peroxide]. / Embolismo gaseoso secundario al uso intraoperatorio de peróxido de hidrógeno.

Hydrogen peroxide solution (H2O2) is used to irrigate and clean wounds. When applied to tissue hydrogen peroxide decomposes rapidly as a result of the action of catalases, releasing oxygen in the process. High pressure irrigation of the washing of closed cavities can cause serious complications. We report a case of gas embolism arising from the use of hydrogen peroxide during surgery for hydatidosis of the liver. A 64-year-old woman underwent surgery for removal of a hydatid cyst of the liver. When pressurized injection of 10 ml of 3% hydrogen peroxide was applied to the cystic cavity, cardiac arrhythmias were observed, a long with decreased PetCO2, hypotension and a "water mill" heart murmur. Gas embolism was suspected and treatment was instated immediately. Clinical course was good and without complications. We wish to warn against the potential dangers of using peroxide during surgery and of the importance of capnography for early diagnosis of gas embolism.

[Abdominal compartmental syndrome in non-injured patients]. / Síndrome compartimental abdominal en pacientes no traumáticos.

Abdominal compartment syndrome (ACS) is characterized by increased intraabdominal pressure and a set of secondary pathophysiological changes in the abdominal. ACS has reappeared in the literature recently in relation to the surgical concept to damage control, applied particularity in contexts of severe abdominal injury polytraumatized patients. We report two cases of ACS that appeared after scheduled abdominal surgery: one after repair of a large eventration and the other in the context of septic shock due to fecaloid peritonitis. Both patients died of multisystem organ failure in spite of surgical decompression. We wish to emphasize that ACS can appear in contexts other than surgery for damage control, and we stress the need to measure intravesical pressure as a reflection of intraabdominal pressure, particularly in certain high risk patients in the postoperative recovery ward. Finally, we review the pathophysiology of ACS and its management, which is based on early treatment to prevent multisystem organ failure with an associated high risk of death.

[Comparative study of 3 techniques for total intravenous anesthesia: midazolam-ketamine, propofol-ketamine, and propofol-fentanyl]. / Estudio comparativo de tres técnicas de anestesia total intravenosa: midazolam-ketamina, propofol-ketamina y propofol-fentanilo.

OBJECTIVE: To compare the characteristics of induction, maintenance and awakening for three techniques of combined total intravenous anesthesia (TIVA): propofol-ketamine, midazolam-ketamine and propofol-fentanyl. PATIENTS AND METHODS: Sixty patients were randomly assigned to three TIVA groups. Group 1 (n = 20) received midazolam, ketamine and vecuronium. Group 2 (n = 20) received propofol, ketamine and vecuronium. Group 3 (n = 20) received propofol, fentanyl and vecuronium. The variables compared were hemodynamic changes during induction and maintenance and upon awakening; time until awakening; and the incidence of postanesthetic complications. We also assessed whether propofol was better than midazolam at preventing the psychomimetic effects of ketamine. RESULTS: The demographic characteristics of the three groups were similar. Hemodynamic variables were most stable in group 2. Perfusion of midazolam-ketamine was accompanied by a significantly higher number of hypertensive peaks. Time to awakening was significantly shorter in Group I (11.8 +/- 5 min) than in group 2 (20.2 +/- 12.5 min); in group 2 time to awakening was 16.6 +/- 5.6 min. Eight patients in group 1, 5 in group 2 and 1 in group 3 reported having bad dreams, the difference between groups 1 and 3 reaching statistical significance. No patient experienced hallucinations and all reported satisfaction with the anesthetic technique used. CONCLUSIONS: TIVA with ketamine and propofol is comparable to the most commonly used combination of propofol and fentanyl and may be an appropriate choice when hemodynamic stability is of great importance; withdrawal 15 min before ending surgery prevents prolonged awakening. Perfusion of midazolam-ketamine is not recommendable for scheduled surgery because it induces too many hypertensive peaks. Although neither midazolam nor propofol completely prevents the psychomimetic effects of ketamine, such effects are not so severe that patients reject the anesthetic technique used.

[Hemodynamic response to intubation with Macintosh and McCoy blades]. / Respuesta hemodinámica a la intubación con las palas de Macintosh y McCoy.

INTRODUCTION: The McCoy laryngoscope incorporates a modification of the Macintosh blade designed to facilitate laryngoscopy and difficult intubation. One end is articulated to allow better viewing of the larynx. Use of this blade reduces pressure placed on tissues in the supraglottic area during laryngoscopy. OBJECTIVE: We designed this study to compare the hemodynamic repercussions of laryngoscopy and tracheal intubation (LTI) performed with either a Macintosh or the McCoy blade. PATIENTS AND METHOD: Sixty ASA I-II patients scheduled for elective surgery requiring LTI were randomly assigned to 2 groups of 30 patients each. In both groups anesthetic induction was achieved with 0.04 mg.kg-1 midazolam, 0.002 mg.kg-1 fentanyl, 2 mg.kg-1 propofol and 0.1 mg.kg-1 vecuronium. In group 1 LTI laryngoscopy and intubation were performed using the Macintosh size 3 blade and in group 2 the McCoy size 3 blade was used. Systolic and diastolic arterial pressures and heart rate were recorded in each patient before anesthetic induction (baseline), 1 minute after induction and 5 minutes after start of LTI. RESULTS: We found no significant differences between the 2 groups at any of the recording times. CONCLUSION: The data obtained do not allow us to assert that there is any difference in hemodynamic response to LTI associated to type of blade used.