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PubMedDate not supplied

[The content of beta-endorphin, met-enkephalin and ACTH in the blood plasma during electric and drug anesthesia].

Beta-endorphin, metenkephaline, and ACTH were radioimmunoassayed in the peripheral blood plasma of 4 groups of patients subjected to microsurgery by different techniques. In 3 groups electropulsed exposure of the CNS was a component of general combined ataralgesia. In group 1 (13 patients) two Lenar devices were employed, in group 2 (5 patients) Skat-202 device, in group 3 (7 patients) Elean device. Group 4 (17 patients) were controls administered drugs according to the same protocols as in the rest three groups. Anesthesia was considered adequate in all the groups. The hypoalgesic effect of electroexposure was the most expressed in group 1: fentanyl was not injected in 53% cases, and in 47% its dose, 0.74 microgram/kg/h, was 2.25 times lower than in controls (1.58 micrograms/kg/hm p < 0.05); the drug doses in groups 2 and 3 (0.82 and 0.8 microgram/kg/h) were 1.9 and 2 times lower than in controls, respectively, p < 0.05. The levels of ACTH and opioid peptides were measured at 6 stages: 1) several days before surgery; 2) after premedication, 10-15 min after the patient was brought into the operation room; 3) before discontinuing nitrogen oxide; 4) after discontinuing nitrogen oxide; 5) when the patient regained consciousness after the end of surgery; and 6) after extubation of the trachea. During surgery under electromedicamentous anesthesia the level of ACTH in the plasma was the same as initially or comparable to the level of this hormone at the same stages in the control group. The content of opioid peptides changed at stressogenic stages of anesthesia and surgery. In patients administered drug anesthesia beta-endorphin levels were shifted, in those operated on under electromedicamentous anesthesia the metenkephaline compound of the opiate system was altered. Activation of various components of endogenous opiate system in electromedicamentous and drug anesthesia may be due to differences in the mechanisms of this types of anesthesia at the given level of the antinociceptive system of the organism. No stable reaction of endorphin level on the electroexposure could be detected. There was no evident relationship between changes in the levels of opioid peptides and the decrease of fentanyl consumption. Besides, it is possible that the analgesic effect of electroexposure is mediated not only by the opioid, but by other mechanisms of endogenous antinociceptive system as well.

Adrenocorticotropic Hormone↗
PubMed2000

Intra- and postoperative factors determining neurological complications after surgery under deep hypothermic circulatory arrest: a retrospective somatosensory evoked potential study.

OBJECTIVES: Intraoperative median nerve SEP monitoring uses the disappearance of cortical and brain stem activities as the criterion to determine that brain cooling is sufficient in deep hypothermic circulatory arrest (CA) surgery. This study presents the results of a retrospective SEP analysis of intraoperative events that engendered neurological complications. METHODS: Median nerve SEP monitoring was performed on 58 consecutive patients who underwent surgery under deep hypothermic CA. The monitoring was retrospectively analyzed and compared with intraoperative events, and postoperative symptoms. RESULTS: Intraoperative SEP abnormalities were observed in 9 out of the 16 patients who presented neurological complications. Among the 7 others, the abnormalities either were present preoperatively (n = 2), occurred postoperatively (n = 3) or only involved the lower limbs (n = 2). Although the mere inspection of the intraoperative SEPs was insufficient to determine the origin of the alterations, their comparison with intraoperative events facilitated the identification of hemodynamic factors in 7 cases and embolism in two cases. There were no patients in whom CA per se caused neurological complications. CONCLUSIONS: Intraoperative SEP monitoring helps identify intraoperative events responsible for neurological complications and prevent these in subsequent procedures. However, the neurological complications of deep hypothermic CA can also be due to pre- or postoperative factors that escape the domain of intraoperative monitoring.

Adolescent↗
PubMed2002

Rocuronium plasma concentrations during three phases of liver transplantation: relationship with early postoperative graft liver function.

BACKGROUND: Previous studies have suggested that neuromuscular blocking agents might be used to assess liver function during liver transplantation. This study examines changes in rocuronium plasma concentration during liver transplantation, to assess graft function. METHODS: A constant-rate infusion of rocuronium was administered to 17 adult patients undergoing liver transplantation. Blood samples were taken at 30-min intervals throughout the procedure, which was divided into three phases: paleo-, an-, and neohepatic. Assay of plasma concentrations of rocuronium was by a gas chromatographic-mass spectrometry technique. Postoperative liver function was followed for up to five days by measuring plasma aminotransferases. RESULTS: In 14 of the 15 patients who survived the transplantation procedure, there was a 7-50% decrease in rocuronium concentration during the neohepatic phase compared with the anhepatic phase. In contrast, rocuronium concentrations increased in the two patients who died after surgery, one as a result of primary non-function and one from massive bleeding. In one patient who survived there was no change in rocuronium concentration. The increase in plasma rocuronium concentration during the neohepatic phase in the two patients who died was consistent with high levels of plasma aminotransferases. CONCLUSIONS: Comparison of changes in plasma rocuronium concentration during the neohepatic phase with early postoperative liver function tests suggests the potential use of rocuronium as a pharmacokinetic probe for predicting liver function during liver transplantation. Further study of rocuronium's potential as an intraoperative pharmacodynamic probe of liver function by measuring neuromuscular paralysis is suggested.

Adult↗
PubMed1997

Transesophageal echocardiography and the perioperative management of valvular heart disease.

Transesophageal echocardiography (TEE) is an integral part of decision-making and monitoring in the perioperative period for patients undergoing valvular heart surgery. Multiplanar probes with improved pre- and intraoperative evaluation, eg, improved accuracy of estimation of mitral regurgitation jet size, have led to a more precise surgical approach. In the intensive care unit, TEE is proving invaluable in diagnosing occult causes of clinical instability that are usually surgically correctable. Advances in imaging technology with three- and four-dimensional TEE will facilitate preoperative decision-making, determine intraoperative approaches to valvular surgery, and provide earlier recognition of complications in the intensive care unit.

Aortic Valve↗
PubMed2005

Portal vein thrombosis in patients undergoing orthotopic liver transplantation: intraoperative endovascular radiological procedures.

PURPOSE: To evaluate the usefulness of endovascular procedures for portal vein complications during orthotopic liver transplantation (OLT). MATERIALS AND METHODS: Between May 1994 and November 2004, we performed 504 OLTs in 464 adults. Seventy-eight patients (16.8%) presented with portal vein thrombosis (PVT). This analysis of patients from May 2000 to September 2004 included 10 patients with PVT, who were treated with endovascular techniques due to low portal flow. We compared this group with patients who were treated surgically with attention to rethrombosis and survival rates. If portal vein problems were due to obstruction, a venoplasty and primary stent placement were performed. We also embolized with coils or surgically ligated remaining competitive portosystemic shunts. RESULTS: Perfusion problems in the allograft were solved in all cases. We placed seven stents and embolized six competitive shunts. One anastomotic dysfunction was repaired. None of the patients died or rethrombosed during surgery or follow-up. CONCLUSION: Endovascular techniques during OLT can resolve some liver graft perfusion problems due to PVT and "steal" phenomena, especially with unsatisfactory eversion thromboendovenectomy in patients with grade IV PVT. Although primary permeability of stents has been good, these results need to be confirmed.

Humans↗
PubMed2006

Attitudes of anaesthetists to awareness and depth of anaesthesia monitoring in the UK.

BACKGROUND AND OBJECTIVE: Awareness with postoperative recall of intraoperative events is a rare but serious complication of general anaesthesia. This survey investigated the attitude of anaesthetists in the UK to awareness and depth of anaesthesia monitoring. METHODS: Questionnaires were sent to 4927 consultant anaesthetists in 285 hospitals in the UK in September 2004. The responses were recorded in an electronic database, summarized and compared with the results of studies performed in Australia and the USA. RESULTS: The response rate was 44%. When judged against published awareness rates, anaesthetists underestimated the incidence of awareness in their own practice (median 1: 5000). One-third of respondents have dealt with patients who have experienced intraoperative recall. The majority of anaesthetists perceived awareness as a minor problem on an 11-point scale (modal score 2, median score 3, IQR 2-5). Eighty-six percent of anaesthetists considered clinical signs unreliable but 91% felt that measurement of end-tidal anaesthetic agent concentration reduces the likelihood of awareness. The majority of anaesthetists would use a monitor at least some of the time if one was available to them. Overall, the attitudes of anaesthetists in the UK, USA and Australia are remarkably similar. CONCLUSIONS: Anaesthetists tend not to view awareness as a serious problem. Although most accept that clinical signs are unreliable indicators of awareness, few believe that monitors of anaesthetic depth should be used for routine cases.

Adult↗
PubMedDate not supplied

Myocardial rewarming mirrors intraoperative mammary artery graft function.

BACKGROUND: The internal mammary artery (IMA) bypass graft provides a satisfactorily long-lasting blood supply to the myocardium. However, its initial flow capacity can be insufficient with subsequent regional myocardial ischemia. We evaluated a method to assess the IMA graft function intraoperatively. METHODS: Twenty-five patients with three-vessel coronary artery disease underwent coronary artery bypass grafting on cardiopulmonary bypass. The in situ IMA was grafted to the left anterior descending coronary artery (LAD) in combination with two saphenous vein grafts to the left circumflex and right coronary artery. Distal anastomoses were performed during cold intermittent blood cardioplegia. After unclamping of the aorta and of the grafted IMA, the temperature at the cardiac anterior and posterior side was measured during the first 5 minutes of warm reperfusion. RESULTS: A sufficient IMA graft function was expressed by a typical rise in temperature: the cardiac anterior and posterior sides showed a parabolic and exponential course, respectively. The rewarming velocity expressed as the first derivative of temperature over time led to a sharp and early peak for the anterior side, and a smaller and delayed peak for the posterior side. Insufficient IMA graft function could be recognized by an atypical temperature course. CONCLUSIONS: Temperature measurement of the heart during warm reperfusion after hypothermic cardioplegia can help to assess the effectiveness of the IMA-LAD graft function.

Coronary Angiography↗
PubMed1991

Clonidine does not delay recovery from anaesthesia.

Clonidine is known to reduce anaesthetic requirements and improve haemodynamic stability when given as premedication. This study, of 46 ASA I-II patients undergoing thyroid surgery, was designed to assess if clonidine interferes with recovery from anaesthesia. Patients were allocated randomly to three groups to receive, 2 h before surgery, flunitrazepam 1 mg, clonidine 150 micrograms, or both drugs. Anaesthesia comprised thiopentone, alfentanil, isoflurane and 70% nitrous oxide in oxygen. Recovery from anaesthesia was assessed using a clinical score, electro-oculographic measurements and reaction times to auditory stimuli. Psychomotor tests were performed the day before surgery and 30, 60, 120 and 240 min after arrival of the patient in the recovery room. Psychomotor performance was decreased significantly after operation in the three groups (P less than 0.05) and returned to baseline at 240 min. There was no significant difference between the three groups. This study indicates that clonidine 150 micrograms orally before surgery does not delay recovery from anaesthesia.

Adolescent↗
PubMed2004

Cardiovascular changes with the laryngeal mask airway in cardiac anaesthesia.

BACKGROUND: The laryngeal mask airway (LMA) causes fewer haemodynamic changes, particularly in mean arterial pressure (MAP) and heart rate (HR), than tracheal intubation using either laryngoscopy or the intubating LMA. There are no data for patients with coronary artery disease. METHOD: We studied 27 patients having coronary artery bypass grafting, prospectively randomized to be managed with either the LMA or tracheal intubation using either laryngoscopy or the ILMA. We used invasive monitoring to compare the haemodynamic effects in each group during induction and emergence from anaesthesia. RESULTS: Both methods of intubation caused an increase in MAP compared with the LMA (P<0.05). Mixed venous oxygen saturation increased in the intubated patients but not with the LMA (P<0.05). HR did not change at induction in the LMA group. Changes at extubation were similar in all groups but cardiac index was lower in the LMA group (P<0.05). CONCLUSION: The LMA allows airway management without hypertension and tachycardia and should be considered when anaesthetizing patients with coronary disease.

Anesthesia, Inhalation↗
PubMed1997

Midlatency auditory evoked potentials predict movements during anesthesia with isoflurane or propofol.

To determine threshold values, sensitivity, and specificity of midlatency auditory evoked potentials (MLAEP) for prediction of spontaneous intraoperative movements, 40 patients undergoing elective laparotomy were studied. Continuous epidural analgesia was used in all patients. To maintain general anesthesia, the patients in Group 1 (n = 20) received isoflurane (0.4-1.2 vol%), and the patients in Group 2 (n = 20) received propofol (3-5 mg x kg(-1) x h(-1) intravenously). Spontaneous movements were documented intraoperatively. Auditory evoked potentials were recorded continuously until the end of anesthesia. Latencies of the peaks V, Na, Pa, Nb, and P1 (ms) and amplitudes Na/Pa, Pa/Nb, and Nb/P1 (microV) were measured. Changes of MLAEP latencies and amplitudes during anesthesia were similar in both groups. Anesthesia led to statistically significant increases in the latencies of Na, Pa, Nb, and P1 and decreases in the amplitudes of Na/Pa, Pa/Nb, and Nb/P1 compared with the awake state. Before and during spontaneous movement observed intraoperatively or during emergence from anesthesia, the latencies of the peaks Na, Pa, Nb, and P1 decreased, and the amplitudes Na/Pa, Pa/Nb, Nb/P1 increased significantly. A threshold value of 60 ms of Nb proved to be most predictive of movement during anesthesia. MLAEP recording seems to be a promising method to monitor the level of anesthesia as defined by spontaneous movement during anesthesia.

Adult↗
PubMed2001

Functional compensation of the left dominant insula for language.

The left dominant insula was recently described as an essential area of speech, inducing definitive language disturbances when injured. We describe a patient with mild dysphasia, harboring a left insular glioma. A functional MRI found activations within the left inferior and middle frontal gyri, superior temporal gyrus, basal ganglia, but not in the insula. Surgery was performed using intraoperative electrical mapping in the awake patient, identifying the same language sites as showed by fMRI. A complete glioma resection was then performed. Despite an entire dominant insula removal, the patient presented no postoperative deficit, and even recovered from the preoperative dysphasia. This case illustrates the brain ability to maintain normal language without the left insula. The mechanisms of compensation are discussed.

Adult↗
PubMed2002

In vivo quantification of retraction deformation modeling for updated image-guidance during neurosurgery.

The use of coregistered preoperative anatomical scans to provide navigational information in the operating room has greatly benefited the field of neurosurgery. Nonetheless, it has been widely acknowledged that significant errors between the operating field and the preoperative images are generated as surgery progresses. Quantification of tissue shift can be accomplished with volumetric intraoperative imaging; however, more functional, lower cost alternative solutions to this challenge are desirable. We are developing the strategy of exploiting a computational model driven by sparse data obtained from intraoperative ultrasound and cortical surface tracking to warp preoperative images to reflect the current state of the operating field. This paper presents an initial quantification of the predictive capability of the current model to computationally capture tissue deformation during retraction in the porcine brain. Performance validation is achieved through comparisons of displacement and pressure predictions to experimental measurements obtained from computed tomographic images and pressure sensor recordings. Group results are based upon a generalized set of boundary conditions for four subjects that, on average, account for at least 75% of tissue motion generated during interhemispheric retraction. Individualized boundary conditions can improve the degree of data-model match by 10% or more but warrant further study. Overall, the level of quantitative agreement achieved in these experiments is encouraging for updating preoperative images to reflect tissue deformation resulting from retraction, especially since model improvements are likely as a result of the intraoperative constraints that can be applied through sparse data collection.

Animals↗
PubMed1992

[The indirect measurement of arterial pressure as a function of cuff width in patients in the immediate preoperative phase, the phase of entry into the operating room and in the postanesthesia phase].

The goal of this study was to compare blood pressure measures using two sizes of cuffs: one standard width (12 cm) and other with correct width that is 0.38 of arm circumference as recommended by American Heart Association. The comparisons were done among surgical patients in mediate perioperative phase, reception area of operation room and postoperative phase during the staying of the patient in the recovery room. The results demonstrated that the arterial blood pressure was hypoestimated by the use of the standard width cuff, reaching values up 30 mmHg in the systolic arterial pressure and 30 mmHg in the diastolic ones.

Adolescent↗
PubMedDate not supplied

Continuous electroencephalographic monitoring during carotid endarterectomy.

Four hundred and twenty-seven carotid endarteriectomies were performed on 377 patients. The electroencephalogram was used as the sole determinant for the use of a carotid shunt in 386 carotid endarterectomies. With clamping of the internal carotid artery, 51 (13%) had electroencephalographic changes. The most common electroencephalographic change (60%) was rapid, ipsilateral attenuation of background activity. In the 30 day follow up period there were 3 deaths (0.7%) and 11 strokes (2.5%). Two patients (0.5%) had intraoperative strokes. The combined morbidity and mortality was 2.8% (12 of 427). Neurologic complications increased significantly with contralateral carotid occlusion. The electroencephalogram correlated well with neurological deficits occurring in surgery, but stump pressures neither correlated with neurological deficits nor electroencephalographic changes. Continuous electroencephalographic monitoring during carotid endarterectomy is an effective method of determining significant cerebral ischemia and the need for a carotid shunt.

Adult↗