Uric acid and acute kidney injury in high-risk patients for developing acute kidney injury undergoing cardiac surgery: A prospective multicenter study.

PURPOSE: It is unclear whether preoperative serum uric acid (SUA) elevation may play a role in the development of acute kidney injury (AKI) associated with cardiac surgery (CSA-AKI). We conducted a cohort study to evaluate the influence of preoperative hyperuricemia on AKI in patients at high risk for developing SC-AKI. DESIGN: Multicenter prospective international cohort study. SETTING: Fourteen university hospitals in Spain and the United Kingdom. PARTICIPANTS: We studied 261 consecutive patients at high risk of developing CSA-AKI, according to a Cleveland score ≥ 4 points, from July to December 2017. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: AKIN criteria were used for the definition of AKI. Multivariable logistic regression models and propensity score-matched pairwise analysis were used to determine the adjusted association between preoperative hyperuricemia (≥7 mg/dL) and AKI. Elevated preoperative AUS (≥7 mg/dL) was present in 190 patients (72.8%), whereas CSA-AKI occurred in 145 patients (55.5%). In multivariable logistic regression models, hyperuricemia was not associated with a significantly increased risk of AKI (adjusted Odds Ratio [OR]: 1.58; 95% confidence interval [CI]: 0.81-3; P = .17). In propensity score-matched analysis of 140 patients, the hyperuricemia group experienced similar adjusted odds of AKI (OR 1.05, 95%CI 0.93-1.19, P = .37). CONCLUSIONS: Hyperuricemia was not associated with an increased risk of AKI in this cohort of patients undergoing cardiac surgery at high risk of developing CSA-AKI.

Transversus abdominal plane block as a sole anesthetic technique for abdominal wall hematoma drainage.

Transversus abdominal plane (TAP) block is a known and useful technique, widely used for postoperative pain management of abdominal wall incisions. During the past years, and following the expansion of ultrasound guided techniques, its use has even gained more adepts. It is usually used as an adjuvant technique, primarily in order to control postoperative pain and reduce opioids consumption. We report the case of an 82 years old patient admitted for drainage of a postoperative abdominal wall hematoma after correction of a McBurney incisional hernia. The corrective surgery had gone on without incident, under general anesthesia with laryngeal mask. Two weeks later, the patient came back to our emergency department with a clear hematoma of the abdominal wall. Surgery was decided. A sole local anesthetic technique was achieved, using a TAP block. The block was performed under ultrasound guidance, using a subcostal approach. The surgery went on without complications. Therefore, TAP block offers a hemodynamic stability, appropriate intra-operative anesthesia and post-surgical analgesia of the abdominal wall.

Modern hydroxyethyl starch and acute kidney injury after cardiac surgery: a prospective multicentre cohort.

BACKGROUND: Recent trials have shown hydroxyethyl starch (HES) solutions increase the risk of acute kidney injury (AKI) in critically ill patients. It is uncertain whether these adverse effects also affect surgical patients. We sought to determine the renal safety of modern tetrastarch (6% HES 130/0.4) use in cardiac surgical patients. METHODS: In this multicentre prospective cohort study, 1058 consecutive patients who underwent cardiac surgery from 15th September 2012 to 15th December 2012 were recruited in 23 Spanish hospitals. RESULTS: We identified 350 patients (33%) administered 6% HES 130/0.4 intraoperatively and postoperatively, and 377 (36%) experienced postoperative AKI (AKI Network criteria). In-hospital death occurred in 45 (4.2%) patients. Patients in the non-HES group had higher Euroscore and more comorbidities including unstable angina, preoperative cardiogenic shock, preoperative intra-aortic balloon pump use, peripheral arterial disease, and pulmonary hypertension. The non-HES group received more intraoperative vasopressors and had longer cardiopulmonary bypass times. After multivariable risk-adjustment, 6% HES 130/0.4 use was not associated with significantly increased risks of AKI (adjusted odds ratio 1.01, 95% CI 0.71-1.46, P=0.91). These results were confirmed by propensity score-matched pairs analyses. CONCLUSIONS: The intraoperative and postoperative use of modern hydroxyethyl starch 6% HES 130/0.4 was not associated with increased risks of AKI and dialysis after cardiac surgery in our multicentre cohort.

[Blood transfusion during heart surgery. A retrospective nested case-control study]. / Transfusión intraoperatoria en cirugía cardiaca. Estudio retrospectivo anidado de casos y controles.

OBJECTIVE: To assess the correlation between intraoperative packed red blood cells transfusion and adverse outcome in a Spanish cohort of cardiac surgery patients. METHODS: Retrospective observational multicentre study. An analysis was performed on the data from 927 cardiac surgery patients treated in 24 Spanish hospitals in 2007. Patients who received intraoperative transfusions were compared with non-transfused patients. Multivariate analyses were performed (including, among others, several items from the Euroscore, surgery type, basal renal status and haemoglobin levels, and Thakar score). RESULTS: Every transfusion of packed red cells was associated with increased postoperative risk of acute kidney damage at 72 hours after surgery, prolonged mechanical ventilation, and need for haemodynamic support. Moreover, transfused patients showed an increased in-hospital mortality rates (Adjusted OR: 1.30; 95% CI: 1.19-1.42), as well as longer hospital stays (almost 4 days). CONCLUSIONS: In this cohort of patients, intraoperative transfusion might independently predict higher risk of early acute kidney damage, prolonged postoperative mechanical ventilation, and a need for haemodynamic support, and reduced short term survival (adjusted OR for mortality: 1.30; 95% CI: 1.19-1.42), and longer hospital stays (4 days longer).

[Acute kidney injury]. / Insuficiencia renal aguda.

Acute kidney injury (AKI) is defined as an abrupt decline in the glomerular filtration rate with accumulation of nitrogenous waste products and the inability to maintain fluid and electrolyte homeostasis. Occurring in 7% of all hospitalized patients and 28% to 35% of those in intensive care units, AKI increases hospital mortality. Early evaluation should include differentiating prerenal and postrenal components from intrinsic renal disease. Biological markers can give early warning of AKI and assist with differential diagnosis and assessment of prognosis. The most effective preventive measure is to maintain adequate circulation and cardiac output, avoiding ischemia- or nephrotoxin-induced injury. To that end, patients and situations of risk must be identified, hemodynamics and diuresis monitored, hypovolemia reversed, and nephrotoxins avoided. Protective agents such as sodium bicarbonate, mannitol, prostagiandins, calcium channel blockers, N-acetyl-L-cysteine, sodium deoxycholate, allopurinol, and pentoxifylline should be used. Treatment includes the elimination of prerenal and postrenal causes of AKI; adjustment of doses according to renal function; avoidance of both overhydration and low arterial pressure; maintenance of electrolytic balance, avoiding hyperkalemia and correcting hyperglycemia; and nutritional support, assuring adequate protein intake. For severe AKI, several modalities of renal replacement therapy, differentiated by mechanism and duration, are available. Timing--neither the best moment to start dialysis nor the optimal duration--has been not established. Early detection of AKI is necessary for preventing progression and starting renal replacement therapy at adjusted doses that reflect metabolic requirements.

[Health-care workload and instructional capacity of Spanish hospitals accredited to train residents in anesthesiology]. / Actividad asistencial y capacidad docente de los hospitales españoles acreditados para la formación de residentes de anestesiología.

OBJECTIVES: To describe the health-care workload and instructional capacity of Spanish hospitals accredited to train anesthesiology residents. METHODS: Survey of supervisors of anesthesiology residents in 2008 to determine caseloads in surgery and obstetrics as well as in pain clinics and critical care units. The results are presented for different Spanish autonomous communities. The maximum theoretical capacity for instruction in accordance with European guidelines is calculated. RESULTS: The 100 hospitals surveyed train 325 residents per year and could theoretically increase the training opportunities they offer, within certain limits. Given optimal distribution of resources, the system could train 397 residents per year in pediatric surgery in 3-month rotations, 442 residents in neurosurgery in 2-month rotations, and 479 residents in thoracic surgery in 1-month rotations. Some Spanish communities presently have problems giving training in the settings of pediatric, thoracic, and major outpatient surgery. Furthermore, even though anesthesiologists are presently responsible for 41.6% of available critical care beds, 46 hospitals do not have a sufficient number of beds to give training in this setting. This shortage may have negative repercussions on the accreditation of training programs. CONCLUSIONS: Although certain limitations were found, the survey showed that the training capacity of the system is greater than accreditation suggests. It would therefore be possible to increase the number of residents.

[Prognostic factors for cancer patients in the postanesthetic recovery unit]. / Pronóstico de los pacientes oncológicos médicos ingresados en Reanimación.

OBJECTIVE: To assess the prognosis of cancer patients in an intensive care unit (ICU), to compare the capabilities of severity scoring systems to predict hospital death, and to improve prediction by adding new variables. PATIENTS AND METHODS: Cohort study in a medical-surgical ICU of a university hospital. Demographic and oncologic characteristics were collected along with death records for all nonsurgical cancer patients admitted between January 1995 and June 2000. Severity scores and risk of death were calculated. RESULTS: In the cohort of 250 patients studied, the hospital mortality rate was 58% and the ICU mortality rate was 38.8%. The best predictions were made with the third version of the Acute Physiology and Chronic Health Evaluation (APACHE III), the total maximum Sequential Organ Failure Assessment (SOFA) score, and the total maximum Multiple Organ Dysfunction Score (MODS). The APACHE II and the Simplified Acute Physiology Score (SAPS), version II, were good predictors, whereas the systems of the International Council on Mining and Metals overestimated hospital mortality and the Modality Prediction Model at 0 and 24 hours (MPM0 and MPM24) and the Logistic Organ Dysfunction System underestimated it. The total maximum SOFA and MODS scores had the greatest discriminating capability and the SOFA0, the MODS0, MPM0, and MPM24 had the poorest. All assessment systems except the APACHE III improved when we added new mortality-associated variables: prior functional status, diabetes, radiographic lung infiltrates, mechanical ventilation, and vasoactive support. CONCLUSIONS: Medical oncology patients should not all be denied intensive care. None of the systems assessed offer clinically relevant advantages for predicting hospital mortality in nonsurgical oncology patients in the ICU, although we recommend the SAPS II because it includes oncologic variables, is easy to score, and has good prognostic capability.

[Anesthesia for the patient with cancer]. / Anestesia del paciente oncológico.

Surgery and radiotherapy provide the basis for local and regional control of cancer. The cancer patient has special characteristics that have implications for anesthesia. Tumors may involve the airways and affect ventilation, hemodynamics and intracranial pressure. Remote tumors can occur in endocrine cancer and in paraneoplastic syndromes. Other systemic complications of the cancer patient include hemostatic changes, immunosuppressant anemia and altered metabolism. Radiotherapy causes changes with anesthetic implications when treatment is directed at the head and neck, mediastinum, lung or surgical area. Chemotherapy is associated with non-specific toxic effects such as mucositis, aplasia and immunosuppression, alopecia and vascular injury; in addition, each chemical has other more specific toxic effects. Chemicals that are toxic for the heart and lungs have the greatest implications for anesthesia. Preoperative assessment should ascertain the effects caused by both the tumor and its treatment. Preparation for surgery includes improving nutrition and possibly inserting a venous port. Management during surgery depends on type of intervention and the patient's physical status, as they will determine the need for invasive monitoring and vessel access. The patient can be given antiemetic and antithrombotic prophylaxis. Important issues in postoperative care are the need for adequate analgesia; provision of early nutrition; antibiotic, antithrombotic and antiemetic prophylaxis; and prevention of ulcers caused by pressure.

A comparative study with oral nifedipine, intravenous nimodipine, and magnesium sulfate in postoperative analgesia.

UNLABELLED: We tested the ability of two L-type calcium channel blockers (nifedipine and nimodipine) and the N-methyl D-aspartate natural antagonist magnesium to decrease morphine requirements and pain in the postoperative period in 92 patients undergoing elective colorectal surgery. In a randomized, double-blinded study, patients were assigned to one of four groups. The control group received placebo. The nifedipine group received 60 mg of oral nifedipine. The magnesium group received an initial dose of 30 mg/kg followed by 10 mg x kg(-1) x h(-1) of magnesium sulfate over 20 h. The nimodipine group received 30 microg x kg(-1) x h(-1) of nimodipine over 20 h. Postoperative morphine consumption was assessed for 48 h. Pain at rest and pain on movement were assessed up to the fifth day postsurgery. There were no differences among groups in postoperative morphine consumption at 12 and 24 h. The nifedipine group consumed more morphine than the control and nimodipine groups during 24-48 h. Pain at rest scores were higher at 16 and 24 h in the nifedipine group than in the other three groups. Pain on movement scores were lower at 72 h in the nimodipine group than in the control and nifedipine groups. In conclusion, the perioperative application of oral nifedipine, IV nimodipine, or IV magnesium sulfate failed to decrease postoperative morphine requirements after colorectal surgery. IMPLICATIONS: The increase of intracellular calcium plays a key role in spinal transmission of pain and in the establishment of central sensitization. We examined the effects of nifedipine, nimodipine, and magnesium sulfate in postoperative analgesia after colorectal surgery. We found no differences in morphine consumption with the administration of each drug alone.

Repeated transient neurological symptoms after spinal anaesthesia with hyperbaric 5% lidocaine.

We report a case of repeated delayed pain after cystoscopy under spinal lidocaine anaesthesia, which may be caused by transient radicular irritation. The possible aetiology of the symptoms is discussed.

Is management of anesthesia in achondroplastic dwarfs really a challenge?

STUDY OBJECTIVE: To review our eight-year anesthetic experience with achondroplastic patients. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: 15 achondroplastic patients who underwent 53 surgical procedures of orthopedic surgery between 1987 and 1994. INTERVENTIONS: Anesthetic technique, drugs, number of incidents, and complications in the intraoperative and postoperative period were recorded. MEASUREMENTS AND MAIN RESULTS: Adequate premedication before the transfer to the operating room was very useful to reduce anxiety and increase cooperation. Inhalation induction was well tolerated and allowed easy peripheral venous cannulation. Only one patient presented difficulties during intubation (on two occasions). In the other patients, we found small difficulties only during ventilation with a face mask, which was easily corrected by modifying the position of the patient and/or inserting an oropharyngeal airway. No adverse effect was identified for any particular anesthetic drug or technique used. CONCLUSIONS: Although the characteristic deformities of achondroplastic patients can impede the management of anesthesia, in our study we found no special difficulties. Airway complications did not occur. Thus, no specific optimal anesthetic regimen can be recommended.

Combination of ondansetron and dexamethasone in the prophylaxis of postoperative nausea and vomiting.

We studied 100 ASA I-II females undergoing general anaesthesia for major gynaecological surgery, in a prospective, double-blind, placebo-controlled, randomized study. Patients received one of four regimens for the prevention of postoperative nausea and vomiting (PONV): ondansetron 4 mg (n = 25), dexamethasone 8 mg (n = 25), ondansetron with dexamethasone (4 mg and 8 mg, respectively, n = 25) or placebo (saline, n = 25) There were no differences in background factors or factors related to operation and anaesthesia, morphine consumption, pain or side effects between groups. The incidence of nausea and emetic episodes in the ondansetron with dexamethasone group was lower than in the placebo (P < 0.01), ondansetron (P < 0.05) and dexamethasone (P = 0.057) groups. There were no differences between ondansetron and dexamethasone, and both were more effective than placebo (P < 0.05 and P < 0.01, respectively). Dexamethasone appeared to be preferable in preventing nausea than emetic episodes. Fewer patients in the ondansetron with dexamethasone group needed antimetic rescue (P < 0.01 vs placebo and P < 0.05 vs ondansetron). We conclude that prophylactic administration of combined ondansetron and dexamethasone is effective in preventing PONV.

[Reduction of the need for blood derivatives in liver transplantation using aprotinin]. / Reducción de los requerimientos de hemoderivados en el trasplante hepático con aprotinina.

OBJECTIVES: To evaluate the efficacy of aprotinin in reducing the need for blood products in orthotopic liver transplantation. PATIENTS AND METHODS: Blood product needs and coagulation test results were studied in 42 adults with cirrhosis of the liver who received orthotopic liver transplants. The first 16 liver transplants carried out without aprotinin (control group) were compared with the next 26 consecutive transplant patients who received aprotinin. Each of the first 9 received a loading dose of 2 million units that was followed by the infusion of half a million units per hour until the end of surgery. The next 17 received the same infusion dose at the same rate but no loading dose. RESULTS: Patients who received aprotinin required fewer transfusions of blood products (5.3 units of packed red blood cells as opposed to 13 units; 9 units of fresh frozen plasma versus 14.6 units; 1.7 units of platelets versus 4.2 units; and 3.8 units of cryoprecipitates versus 8.8 units). We observed a marked reduction of fibrinolysis (less increase in D dimers after removal of the liver when aprotinin was used. CONCLUSIONS: Prophylactic use of aprotinin during surgery has a beneficial effect on hemostatic mechanisms, reducing the need for blood products. A reduction in fibrinolysis seems to contribute to this effect.

[Does propofol have advantages over midazolam and isoflurane? Comparative study of 2 total intravenous anesthesia techniques using midazolam and propofol, versus balanced anesthesia with isoflurane]. / Tiene ventajas propofol sobre midazolam e isoflurano? Estudio comparativo de dos técnicas de anestesia total intravenosa con midazolam y propofol, y anestesia balanceada con isoflurano.

OBJECTIVES: To compare two techniques for total intravenous anesthesia (TIVA): midazolam-alfentanil-flumazenil and propofol-alfentanil, contrasting them with combined anesthesia (thiopental-isoflurane-alfentanil) and assessing the efficacy of flumazenil in continuous perfusion for preventing resedation in TIVA with midazolam. PATIENTS AND METHODS: The efficacy and clinical tolerance of the 3 anesthetic techniques with propofol, midazolam or isoflurane were studied in 63 patients undergoing elective breast, lumbar or gynecological surgery. Anesthetic induction was achieved with midazolam 0.3 mg/kg-1 (group M), propofol 2.5 mg/kg-1 (group P) or thiopental 3 mg/kg-1 (group I); all patients also received 50 micrograms/kg-1 alfentanil and vecuronium bromide 0.12 mg/kg-1/h-1. Maintenance was achieved with midazolam in perfusion at 0.12 mg/kg-1/h-1 (group M); propofol in perfusion at 7 mg/kg-1/h-1 and a pre-incision dose of 1.5 mg/kg-1 (group P); and isoflurane at 1.15% (group I). The 3 groups also received one pre-incision dose of alfentanil 25 micrograms/kg-1 and post-incision perfusion at 60 micrograms/kg-1/h-1. The infusion of alfentanil was changed by amounts of 20 micrograms/kg-1/h-1 in accordance with the patient's response to surgery. After surgery patients in group M received flumazenil 0.5 mg i.v. over 30 sec and a perfusion of flumazenil 0.5 mg over 60 min. Parameters indicating efficacy were: 1) total dose and timing of alfentanil; 2) number of instances of inadequate anesthesia; 3) peri-operative amnesia; 4) times of awakening and extubation after surgery, and 5) the number of patients in each group who required naloxone. Parameters indicating tolerance were: 1) hemodynamic variables; 2) the number of postoperative desaturations; 3) level of sedation, comprehension and motor coordination and orientation; 4) the "G/g detection" test and the memory recall test; 5) adverse side effects; 6) need for postoperative analgesia, and 7) evaluation of the anesthetic technique. RESULTS: The 3 techniques afforded effective control of hemodynamic response to intubation and surgical incision. Anesthetic maintenance was easy and safe with isoflurane and propofol. Higher doses of alfentanil, however, were needed with midazolam and we found a higher incidence of signs of superficial anesthesia. Reversion of midazolam with flumazenil 0.5 mg i.v. produced earlier awakening, although this was followed later by relapse into hypno-sedation that could not be prevented with a perfusion of flumazenil. Although recovery from anesthesia was slower with propofol than with isoflurane, we observed no differences in level of sedation, motor coordination and postoperative comprehension. Maintenance with isoflurane produced a higher incidence of adverse side effects such as tremors and nausea after surgery. CONCLUSIONS: None of the TIVA techniques proved superior in all the parameters studied during anesthetic maintenance when compared with balanced isoflurane-alfentanil, although the propofol-alfentanil combination was found to be superior to that of midazolam-alfentanil. After anesthesia, however, recovery was better with the association of propofol-alfentanil and adverse side effects were fewer. Flumazenil at the doses used was ineffective for preventing resedation due to midazolam.

[Ambulatory pediatric anesthesia: preanesthetic evaluation, anesthetic techniques, and immediate postoperative care]. / La anestesia pediátrica ambulatoria: evaluación preanestésica, técnicas anestésicas y postoperatorio inmediato.

The advantages of pediatric out-patient surgery are: 1) greater psychological ease; 2) lower rate of infection; 3) less impact on patient habits, and 4) lower cost. Surgery must not involve organs, must have a low rate of complications, and be short. The preanesthetic interview should include clinical history and complementary examinations, information on anesthetic technique, perioperative recommendations and psychological preparation of parents and child. Detailed information reassures parents and improves collaboration; their presence during induction may be useful. At this time complete fasting is not recommended; although solids are not permitted, clear liquids should be taken up to 2-3 hours before anesthesia. In this way the child is less irritable and hypoglycemia and hypotension during inhalational induction are prevented. Low doses of midazolam and ketamine have been used for premedication, which though possibly useful, is not recommended because recovery may be prolonged. Halogenated anesthetics are very useful, with nitrous oxide providing an excellent complement. The potentially toxic effect of halothane on the liver does not keep this agent from being the most popular. Recovery is fast with any of the usual hypnotics (etomidate, propofol, thiopentone). Although thiopentone continues to be the hypnotic drug of reference, propofol's versatility is causing it to gain wider acceptance. The use of atracurium or vecuronium is justified if the dose is adjusted in keeping with type of surgery and duration. Intraoperative analgesics include meperidine, fentanyl and alfentanyl; morphine is not recommended. Should tracheal intubation be necessary, laryngeal edema may be avoided by gentle, cautious laryngoscopy, the use of a tube without a balloon, and 3 h of postanesthetic observation. A laryngeal mask may serve as an alternative to tracheal intubation. Local-regional anesthesia, excepting epidural and spinal anesthesia, offers a number of advantages: blockade of nociceptive stimuli, avoidance of opioid drugs, rapid and pleasant awakening (excellent for postoperative analgesia), and less need for postoperative analgesics. The postoperative complications seen most often are related to respiration or hypertension, making routine postanesthetic pulse oximetry a recommendation. The most frequently used analgesics are paracetamol, magnesium dipyrone, diclofenac, ketorolac, or codeine compounds. Although the incidence of nausea and vomiting is low in children, they are frequently a cause of hospitalization. Inappropriate postoperative care can increase the rate of admissions and medico-legal problems.(ABSTRACT TRUNCATED AT 400 WORDS)

[Comparison of the effects of isoflurane and alfentanyl on the mononuclear-phagocytic system]. / Comparación de los efectos del isoflurano y del alfentanilo sobre el sistema mononuclear-fagocítico.

BACKGROUND AIMS: The effects of two anesthetic agents, alfentanil and isoflurane, on the macrophage-monocytic system and the relation with the adrenocortical-hypophyseal axis were analyzed. MATERIAL AND METHODS: Thirty ASA I-II patients submitted to elective surgery were distributed into two groups: group I, analgesic anesthesia with alfentanil 100 micrograms/kg, a perfusion of 2-3 micrograms/kg/min and naloxone 0.2-0.4 mg upon termination of surgery; group II, inhalation anesthesia with isoflurane at 2-2.5% and O2/air = 1/1. HLA-DR membrane receptors and vimentin threads of the cytoskeleton were determined in basal conditions, at one hour and two hours of induction and upon termination of surgery by means of indirect immunofluorescence with the use of monoclonal antibodies. Phagocytosis of latex particles was also measured and ACTH and cortisol levels were obtained by radioimmunoassay. RESULTS: In group I (alfentanil) a decrease (p < 0.01) of all the monocyte parameters analyzed, which was more significant than that observed in group II (isoflurane), was observed. In group II only the expression of HLA-DR and the index of phagocytosis (p < 0.05) were statistically significant. Following the administration of naloxone a reversion of these parameters was observed. The maximum immune depression corresponded with the lowest values of ACTH and cortisol (group I) with surgical stress being discarded as the cause of this immunodepression. CONCLUSIONS: Alfentanil produces a monocytic depression which reverses following the administration of naloxone, thus discarding surgical stress as the cause of this immunodepression suggesting a mechanism mediated by opiate receptors. With regards to isoflurane, the functions of the mononuclear-phagocytic system were hardly altered in the patient studied.

[Depression of the mononuclear phagocyte system caused by high doses of narcotics]. / Depresión del sistema mononuclear-fagocítico provocada por altas dosis de morfínicos.

We evaluated in human monocytes the effect of high doses of alfentanyl on the expression of vimentin filaments, the phagocytic activity and the membrane display of HLA-DR molecules in the subjects undergoing surgery. The study was performed on 30 patients, ASAI-II. The patients received 100 mcg/kg i.v. of Alfentanil and the maintenance of anaesthesia was made with Alfentanil (2-3 mcg/kg/min.). The patients were randomized in two groups. The patients were ventilated with N2O:O2 (1:1) (Group I) or air: O2 (1:1) (Group II). After surgery, all patients of the Group II received Naloxone (0.2-0.4 mg). Central venous blood samples were obtained before induction, one and two hours after induction of anaesthesia and at the end of surgery. Separation of monocytes was performed according to Boyum technique. CD35 and HLA-DR molecules and vimentin filaments were studied by indirect immunofluorescence method using monoclonal antibodies. Percentage of positive cells were read with a cytofluorometer. The phagocytic function of monocytes was determined by ingestion of latex particles. Cortisol and ACTH plasma levels were determined by RIA. High doses of Alfentanyl depress phagocytic function and membrane display of CD35 and HLA-DR molecules in monocyte and induce marked changes in the organization of vimentin filaments in these cells in patients undergoing surgery. This monocytic depression was more marked in the patients ventilated with N2O. In our results there was uninhibition of ACTH and cortisol plasma levels responses to surgical stress by Alfentanil administration. Since the effects of Alfentanil were reversed by Naloxone, an opioid receptor mechanism seems to mediate these events.