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PubMed1989

[Anesthetic management in surgery of thoracic aortic aneurysms--a report of eleven cases].

Anesthetic management of patients with thoracic aneurysm is discussed. During a period of two years, 11 cases were observed; 7 cases of dissecting aneurysm and 4 cases of true aneurysm. Dissecting aneurysms were of DeBakey's type 1 in 5 cases and of DeBakey's type 2 in 2 cases. Four cases had hypertension. As many of these patients often have hypertension, it is important not to change the circulatory dynamics during induction of anesthesia. We employed high dose fentanyl in 9 cases and used nitroglycerin or nitroprusside to control systolic blood pressure at about 100-120 mmHg. Massive bleeding can occur during intraoperative period and it is important to secure a sufficient number of intravenous routes to protect the central nervous system during cardio-pulmonary bypass.

Aged↗
PubMed2004

Determinants of regional myocardial acidosis during cardiac surgery.

BACKGROUND: Intraoperative regional myocardial acidosis (RMA) during cardiac surgery has been shown to be reflective of regional myocardial ischemia and an independent predictor of adverse postoperative outcomes. This study identifies the determinants of intraoperative RMA. METHODS: Intramyocardial tissue pH(37C) in the anterior and posterior LV walls was measured in 641 adult patients during cardiac surgery. RMA at two intraoperative periods was quantified as integrated mean pH(37C) < 6.35 during aortic clamping (AC) and pH(37C) < 6.73 at the end of cardiopulmonary bypass (CPB). These pH thresholds were chosen because of their demonstrated relationship to long-term patient survival. Multivariate logistic regression models were constructed. An acidosis prediction score was constructed based on the factors determining RMA at the end of CPB. RESULTS: Independent determinants of RMA during AC were preoperative New York Heart Association class III/IV (P = .007), current smoker (P = .0088), pH(37C) < 6.63 prior to AC (P < .0001), and intraoperative myocardial management technique (P = .0001). Independent determinants of RMA at end of CPB were ASA class IV/V (P = .0042), pH(37C) < 6.63 prior to AC (P = .035), pH(37C) < 6.35 during AC (P = .001), and total duration of CPB > or = 212 minutes (P = .001). CONCLUSIONS: RMA during cardiac surgery is determined by patient risk factors, the magnitude of preceding regional myocardial acidosis, and the duration of CPB.

Acidosis↗
PubMed1996

Intraoperative positioning of surgical patients.

All perioperative team members are responsible for the safe positioning of surgical patients. Circulating nurses coordinate the positioning of patients during intraoperative periods of care. Skilled perioperative nursing interventions afford patients safe and comfortable positioning during surgery, ensure optimal exposures of surgical sites, and prevent postoperative complications (e.g., pressure injuries, neuropathies, cardiovascular and respiratory compromises). Perioperative nurses should have a working knowledge of anatomy and physiology, patient risk factors, injury mechanisms, potential complications, and positioning devices before placing patients in required perioperative positions.

Humans↗
PubMed1992

The risk of myocardial ischemia in patients receiving desflurane versus sufentanil anesthesia for coronary artery bypass graft surgery. The S.P.I. Research Group.

Desflurane, a coronary vasodilator, may induce myocardial ischemia in patients with coronary artery disease. To determine whether desflurane is safe to administer to the at-risk patient population (with known coronary artery disease), we compared the incidence and characteristics of perioperative myocardial ischemia in 200 patients undergoing coronary artery bypass graft (CABG) surgery randomly assigned to receive desflurane (thiopental adjuvant) versus sufentanil anesthesia. Under conditions of hemodynamic control, perioperative ischemia was assessed using continuous echocardiography (precordial: during induction; transesophageal: during surgery) and Holter electrocardiography (ECG); hemodynamics (including pulmonary artery pressure) were measured continuously. Hemodynamic results: During induction, no significant changes in hemodynamics occurred in the sufentanil group, while in the desflurane group, heart rate, systemic and pulmonary arterial pressure increased and stroke volume decreased significantly. During the intraoperative period, the incidence of hemodynamic variations was low in both anesthetic groups; however, the prebypass incidence of tachycardia (greater than 120% of preoperative baseline heart rate) was greater in the desflurane group (4 +/- 7% of total time monitored) than in the sufentanil group (1 +/- 6%) (P = 0.0003). Similarly, the incidence of prebypass hypotension (less than 80% of preoperative baseline systolic arterial blood pressure) was greater in the desflurane group (21 +/- 14%) than in the sufentanil group (15 +/- 16%) (P = 0.01). ECG results: Preoperatively, 15% (28/191) of patients developed ECG ischemia, with no difference between patients who received desflurane, 13% (12/96) or sufentanil, 16% (16/95) (P = 0.6). During anesthetic induction, 9% (9/99) of patients who received desflurane developed ECG ischemia, compared with 0% (0/98) who received sufentanil (P = 0.007). During the prebypass period, 5% (10/197) of patients developed ECG ischemia, with no difference between patients who received desflurane, 7% (7/99) or sufentanil, 3% (3/98) (P = 0.3). Postbypass, 12% (24/194) of patients developed ECG ischemic changes, with no difference between patients who received desflurane, 13% (13/97) or sufentanil, 11% (11/96) (P = 0.9). Echocardiographic results: The incidence of precordial echocardiographic ischemia during anesthetic induction was 13% (5/39) in the desflurane group versus 0% (0/29) in the sufentanil group (P = 0.1). Moderate to severe transesophageal echocardiographic (TEE) ischemic episodes occurred in 12% (21/175) of patients during prebypass, with no significant difference between the desflurane group, 16% (15/91) and the sufentanil group, 7% (6/84) (P = 0.09). TEE ischemic episodes occurred in 27% (49/178) of patients during the postbypass period, with no difference between the desflurane, 29% (27/92) and sufentanil, 25% (22/86) groups (P = 0.7).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1996

Physiological perspectives of therapy in bronchial hyperreactivity.

PURPOSE: This paper reviews the literature on the aetiology and therapy of bronchial hyperreactivity to describe the underlying pathophysiology, identify patients at risk and update knowledge on new and existing therapies. SOURCE: Information was obtained from monograms on New Drugs for Asthma, Respiratory Medicine: recent advances, Agents and Actions Supplements, Pulmonary Pharmacology, Anesth Analg, the European Journal of Respiration and a Medline literature search. PRINCIPAL FINDINGS: Reduced airway calibre, increased bronchial contractility, altered permeability of the bronchial mucosa, humoral and cellular mediators, and dysfunctional neural regulation are critical factors for bronchial hyperreactivity, a characteristic feature of hyperreactive airways which results in bronchoconstriction after exposure to varied stimuli. Preoperative anaesthetic considerations in these patients include FEV1 and PEFR testing to assess the severity and for optimal control of the condition. Bronchospasm causing hypoxaemia is the major intraoperative problem anticipated in these patients. Current therapeutic management of bronchoconstriction focuses on the beta 2 agonists, theophylline and steroids. Besides relaxing the airway smooth muscle these agents are all capable of altering bronchial inflammatory responses. Future developments of therapy are directed towards the inflammatory components of the disease. CONCLUSION: This review has presented background information on physiological mechanisms of smooth muscle contractility, pathophysiological alterations of bronchial contractility and the pharmacological basis of therapy in bronchoconstrictive disease. Information is presented to enable the prompt arrest and reversal of airway constriction, and to maintain prophylactic treatment during the perioperative period. Intraoperative bronchospasm is managed by adequate oxygenation and reversal of bronchoconstriction.

Bronchi↗
PubMed1988

Perioperative management of diabetic subjects. Subcutaneous versus intravenous insulin administration during glucose-potassium infusion.

The purpose of this study was to validate methods for the perioperative management of diabetic patients that meet the prerequisites of simplicity, applicability in the absence of a diabetologist, and flexibility, to rapidly meet changing metabolic requirements. The patients were divided into two groups that were comparable for age, sex distribution, type of diabetes, and type of surgical procedures. The results show that intravenous insulin administration achieved better glycemic control during the intraoperative period, whereas it did not offer advantages over the subcutaneous route during the pre- and postoperative periods. The satisfactory degree of steady glycemic control achieved and the absence of hypoglycemic episodes indicate that the separate administration of insulin and glucose plus electrolytes is an effective and safe management modality for diabetic patients undergoing major surgery.

Adult↗
PubMed1989

[Auditory evoked potentials in the monitoring of 15 laser microsurgeries of the brain stem].

Based upon the results observed in 15 patients submitted to tumor resection by the CO2 microlaser technique and submitted to brain stem auditive evoked potential (BAEP) intraoperative determination, the authors emphasize the importance of the technique. BAEP during the intraoperative period and the ultrasonic control of removal of tumors proved useful in the 15 cases of brain stem tumors or tumor adherent to it. Morbidity and mortality are described, and the important changes in BAEP that precede bradycardia are detailed. The importance of advances obtained through BAEP in peroperative control in such surgeries is stressed.

Adult↗
PubMed1996

Spectral edge frequency of the electroencephalogram to monitor "depth" of anaesthesia with isoflurane or propofol.

To determine threshold values, sensitivity and specificity of the spectral edge frequency (SEF) of the electroencephalogram (EEG) that indicate intraoperative movements, we studied 49 patients undergoing, elective laparotomy. Extradural analgesia was used in all patients. To maintain general anaesthesia, patients in group 1 (n = 23) received 0.4-1.2 vol% isoflurane and patients in group 2 (n = 24) propofol 3-5 mg kg-1 h-1 i.v. During operation and emergence from anaesthesia, spontaneous purposeful movements were documented. The EEG was recorded continuously in the awake state until the end of anaesthesia. Power spectral analysis calculated the SEF and power in the delta, theta, alpha and beta bands and the delta ratio. Adequate anaesthesia caused a statistically significant decrease in SEF from 16 to 12 Hz. Power in the beta band decreased and power in the theta band and total power increased compared with the awake state. Before and during movements observed in the intraoperative period or during emergence from general anaesthesia, SEF increased from 12 to 18 Hz, the power in beta band increased and theta power decreased compared with the state of adequate anaesthesia. A threshold value of SEF 14 Hz to predict movements during anaesthesia had a sensitivity of 72% and specificity of 82%.

Adult↗
PubMed1995

Antibiotic therapy and the anesthesiologist.

The anesthesiologist is frequently responsible for administering antibiotics in the immediate preoperative and intraoperative periods. Anesthesiologists often are not trained in the administration of antibiotics, which can be associated with both acute and long-term complications including potentiation of neuromuscular blocking agents, allergic reactions, and end-organ toxicity. The indications for perioperative antibiotics, proper method of administration, and occurrence and treatment of major side effects of the more commonly recommended prophylactic antibiotics are discussed.

Anesthesia↗
PubMed1996

Intraoperative maintenance of tissue perfusion prevents ARDS. Adult Respiratory Distress Syndrome.

Patients undergoing prolonged, complex oncological surgery are at increased risk of developing the adult respiratory distress syndrome (ARDS) and other organ failures. Our hypothesis is that maintaining adequate tissue perfusion and oxygenation may prevent tissue hypoxia and acidosis in pulmonary, peripheral, and splanchnic microcirculations. Experimental evidence suggests that the hypoxic, acidotic endothelium stimulates the release of cytokines, kinins, and other mediators. We developed and tested an intraoperative protocol for surgical patients likely to develop ARDS and organ dysfunction; the protocol focuses on the intraoperative period but is not limited to this time. Nitroglycerin and fluids were used to maintain tissue perfusion and prevent tissue hypoxia as reflected by transcutaneous oxygen tension values. In 155 high-risk patients, none developed ARDS. We conclude that maintenance of tissue perfusion and oxygenation in high-risk surgical patients decreases the incidence of ARDS.

Adult↗
PubMedDate not supplied

[Variation cardiac intervalometry -- a component of neurophysiological monitoring].

The course of intraoperative period is retrospectively analyzed in patients operated on for bulky formations of the brain. Mathematical analysis of cardiac rhythm structure, performed using an original method within the framework of operation monitoring, detected early signs of disorders in adaptation systems, indicative of insufficient anesthesia and overrun physiological permissiveness during the main stages of operation. The results of the study extend our notions on the potentialities of traditional monitoring and improve the efficiency of neuroanesthesiological support and choice of surgical strategy.

Adaptation, Physiological↗
PubMed1998

Is there a relationship between hypertension and lower-extremity contracture release in cerebral palsy?

Recent reports have suggested a relationship between release of lower-extremity contractures and the development of hypertension in cerebral palsy and poliomyelitis patients. A retrospective study was performed on 119 cerebral palsy patients who had undergone lower-extremity contracture releases. Temporary elevation of systolic blood pressure in the perioperative and intraoperative periods occurred in 46 patients (39%), and temporary elevation of diastolic blood pressure occurred in 14 patients (12%). Type of cerebral palsy, patient age, patient sex, type of anesthesia, and type of procedure were not significantly correlated with the temporary blood pressure elevations. No patient developed sustained elevation of systolic and diastolic blood pressure. We conclude that lower-extremity contracture release in pediatric patients is not associated with an increased incidence of postoperative hypertension.

Adolescent↗
PubMed2006

Comparison of the pretreatment effects of mixed vasodilators (3-D solution) on radial and internal thoracic arteries by using a 3-dimensional anaglyph electron microscope technique.

OBJECTIVE: Currently, internal thoracic arteries (ITA) and radial arteries (RA) are the first choice of conduits for coronary artery bypass grafts (CABG). Because the perioperative vasospasm continues to be a major problem, a number of pharmacologic agents such as papaverine, calcium receptor blockers, nitroglycerine, and phenoxybenzamine have been suggested as topical antispasmodics that may be used in the pre- and postoperative periods. In the present study, we investigated the quantitative efficacies of the mixed solution, which included verapamil, nitroglycerin, and papaverine, on RA and ITA using a scanning electron microscope with a 3-dimensional anaglyph technique. METHODS: Diameter changes of RA and ITA in response to clinically important vasodilators were measured on 40 RA and 40 ITA rings from patients who had been subjected to coronary artery bypass procedure after 20 minutes of ex vivo incubation with verapamil (45 microg/L), nitroglycerin (45 microg/L), papaverine solution (266 micromol/L or 0.1 micro/mL), and 30 mL autologous heparinized whole blood (individual patient's blood obtained before cardiopulmonary bypass contained 100 IU of heparin per kg of patient weight). The pretreatment action was assessed by measuring the response to vasodilators. RESULTS: In all cases, we did not observe graft vasospasm in any of the conduits during the intraoperative period between postanastomosis and sternal closure. In the postoperative period, we did not record any evidence of ischemic change in patients' electrocardiographic and myocardial enzyme analyses. None of the cases required inotropic support after the operation. The diameters of the pretreated RA and ITA were: minimum, 2.1 mm; maximum, 4.0 mm; and mean value, 2.80 +/- 0.46 mm. The diameters of the pretreated ITA were: minimum, 1.2 mm; maximum, 2.5 mm; and mean value, 1.76 +/- 0.35 mm. Incubated arterial segment diameters for the RA were: minimum, 2.8 mm; maximum, 5.2 mm; and mean value, 3.95 +/- 0.65 mm. These values for the ITA were: minimum, 1.5 mm; maximum, 3.9 mm; and mean value, 2.37 +/- 0.50 mm. These findings were statistically significant for both arterial grafts (P <.05). CONCLUSIONS: According to our study findings, the mixed solution demonstrates a broad range of efficacy. We conclude that the described vasodilator solution with heparinized autologous blood seems to be very effective and may be used as a pretreatment agent in CABG conduits. Although papaverine has the shortest duration of action, its efficiency is increased by verapamil and nitroglycerin, in our opinion. To the best of our knowledge, high-quality imaging of CABG conduits with the 3-D anaglyph technique using a scanning electron microscope was a first in the literature. This technical approach may be used for confirming the ultrastructural anatomy and the quantitative vasodilator effects of arterial conduits. We believe that valuable anatomo-pathologic details of the CABG conduit can be obtained by this technique.

Coronary Artery Bypass↗
PubMed2003

Delayed paraplegia after thoracic and thoracoabdominal aneurysm repair: a continuing risk.

BACKGROUND: Paraplegia or paraparesis after otherwise successful thoracic or thoracoabdominal aortic reconstruction is a devastating complication for patient and physician. Interventions for its prevention have focused primarily on the intraoperative period. We have recently noted a significant incidence of delayed-onset neurologic deficit. METHODS: We reviewed our most recent 5-year experience with thoracic and thoracoabdominal reconstruction to examine the incidence of and potential contributors to delayed paraplegia or paraparesis. RESULTS: Between June 1996 and June 2001, 60 patients (29 men, 31 women) underwent repair of isolated thoracic (n = 26) or thoracoabdominal aortic aneurysm (Crawford I, n = 7; Crawford II, n = 14; Crawford III, n = 12; Crawford IV, n = 1) by the cardiac and vascular surgical services collaboratively. Repair was performed endovascularly in 6, and open with either circulatory arrest in 12, partial left heart bypass in 37, or partial femorofemoral bypass in 5. Operative mortality was 9.3% (5 of 54 patients) for open repair and 0% for endovascular repair. Paraplegia or paraparesis occurred in 6 (10%) patients of which 83.3% (5 of 6) were delayed in onset. All patients with delayed paraplegia or paraparesis had degenerative aneurysms of Crawford extent II (n = 3) or III (n = 2), had intraoperative left heart bypass, and had perioperative spinal drainage. Delayed paraplegia or paraparesis occurred up to 27 days postoperatively, and was associated with a documented episode of hypotension in 60% (3 of 5) of patients. CONCLUSIONS: Improvements in intraoperative management may have reduced immediate paraplegia or paraparesis among vulnerable patients only to leave them at risk of delayed-onset deficit. Postoperative care, including assiduous attention to avoidance of even transient hypotension, must be tailored to this patient population.

Adult↗
PubMed2002

Effectiveness of acute normovolemic hemodilution to minimize allogeneic blood transfusion in major liver resections.

BACKGROUND: Liver resection is a major operation for which, even with the improvements in surgical and anesthetic techniques, the reported rate of blood transfusion was rarely less than 30%. About 60% of transfused patients require only 1 or 2 units of blood, a blood requirement that may be accommodated by the use of acute normovolemic hemodilution (ANH). METHODS: The efficacy, hemodynamic effects, and safety of ANH were investigated in a randomized, active-control study in patients with American Society of Anesthesiologists status I-II who were undergoing major liver resection with fentanyl-nitrous oxide-isoflurane anesthesia. Patients were randomized to the ANH (n = 39) or control group (n = 39). Patients in the ANH group underwent hemodilution to a target hematocrit of 24%. The indication for blood transfusion was standardized. In both groups transfusion was started at a hematocrit of 20%. The primary efficacy endpoint was the avoidance of allogeneic blood transfusion in the intraoperative period and first 72 h after surgery. Various laboratory and hemodynamic parameters as well as postoperative morbidity were monitored to define the safety of ANH in this patient population. RESULTS: During the perioperative period, 14 control patients (36%) received at least one unit of allogeneic blood compared with 4 patients (10%) in the ANH group ( < 0.05). The hemodilution process was not associated with significant changes in patients' hemodynamics. Morbidity was similar between the control and the ANH groups. Postoperative hematocrit levels and biochemical liver, renal, and standard coagulation test results were similar in both groups. CONCLUSIONS: Acute normovolemic hemodilution in patients with American Society of Anesthesiologists status I-II undergoing major liver resection may allow a significant number of patients to avoid exposure to allogeneic blood.

Adult↗
PubMed2001

Auditory information processing during adequate propofol anesthesia monitored by electroencephalogram bispectral index.

UNLABELLED: Memory for intraoperative events may arise from inadequate anesthesia when the hypnotic state is not continuously monitored. Electroencephalogram bispectral index (BIS) enables monitoring of the hypnotic state and titration of anesthesia to an adequate level (BIS 40 to 60). At this level, preserved memory function has been observed in trauma patients. We investigated memory formation in elective surgical outpatients during target-controlled propofol anesthesia supplemented with alfentanil. While BIS remained between 40 and 60, patients listened to a tape with either familiar instances (exemplars) from two categories (Experimental [E] group, n = 41) or bird sounds (Control [C] group, n = 41). After recovery, memory was tested directly and indirectly. BIS during audio presentation was on average (+/- SD) 44 +/- 5 and 46 +/- 5 for Groups E and C, respectively. No patient consciously recalled the intraoperative period, nor were presented words recognized reliably (Group E, 0.9 +/- 0.8 hits; Group C, 0.8 +/- 0.8 hits) (P = 0.7). When asked to generate category exemplars, Group E named 2.10 +/- 1.0 hits versus 1.98 +/- 1.0 in Group C (P = 0.9). We found no explicit or implicit memory effect of familiar words presented during adequate propofol anesthesia at BIS levels between 40 and 60 in elective surgical patients. IMPLICATIONS: This study suggests that stable levels of adequate hypnosis may prevent information processing and memory formation during general anesthesia and supports the feasibility of electroencephalogram bispectral index as a monitor of adequate anesthesia.

Acoustic Stimulation↗
PubMed2000

Comparison of erbium:yttrium-aluminum-garnet-laser vitrectomy and mechanical vitrectomy: a clinical study.

OBJECTIVE: To evaluate the clinical usefulness of the erbium:YAG (yttrium-aluminum-garnet) laser for vitrectomy and to compare it with a conventional mechanical vitrectomy system regarding the intraoperative parameters. DESIGN: Prospective, randomized, clinical trial. PARTICIPANTS: Thirty eyes of 30 patients underwent vitrectomy, 15 eyes in each group. METHODS: For mechanical vitrectomy, a commercially available vitrectomy unit was used. The operating parameters, cutting rate (7 Hz = 420 cpm), maximal suction force (300 mmHg), and aspiration flow (20 ml/min), were held constant. A newly developed erbium (Er):YAG laser unit and handpiece was used for laser vitrectomy with predetermined parameters for cutting rate (70 Hz = 4200 cpm), maximal suction force (50 mmHg), and aspiration flow (20 ml/min). Surgery parameters were recorded in real time and the operation was video recorded. The clinical follow-up time was a minimum of 3 months (average, 6.2 months; range, 3-9 months). MAIN OUTCOME MEASUREMENTS: The surgery time was comparable in both groups. During Er:YAG laser vitrectomy, the average suction force was significantly reduced (P< 0.001) compared with that during mechanical vitrectomy. The mean-square variation in suction as a measure to quantify the forces acting on intraocular structures during surgery was significantly smaller in the Er:YAG laser vitrectomy group (P << 0.001). CONCLUSIONS: Erbium:YAG laser vitrectomy may provide a semicontinuous procedure. This technique minimizes periodical intraoperative forces and movements of intraocular structures and may provide, therefore, a safer vitrectomy.

Aged↗
PubMed2001

Intraoperative epidural blockade prevents the increase in protein breakdown after abdominal surgery.

BACKGROUND: The aim of this study was to investigate the effect of epidural blockade with bupivacaine, restricted to the intraoperative period, on protein catabolism after major abdominal surgery. METHODS: Fourteen patients undergoing cystoprostatectomy were randomly assigned to receive either general anaesthesia with isoflurane (control group, n=7) or a combination of general anaesthesia and epidural blockade with bupivacaine from segment T4 to S5 (epidural group, n=7). Rates of urea (Ra urea) and glucose production (Ra glucose) were measured three days before and three days after the operation using stable isotope tracers ([15N2]urea, [6,6-2H2]glucose). Protein breakdown was calculated from the urea production rate. Plasma concentrations of metabolic substrates (urea, glucose, lactate, glycerol, amino acids) and hormones (insulin, glucagon, cortisol, adrenaline, noradrenaline) were also determined. RESULTS: Protein breakdown significantly increased after surgery in the control group (P<0.05), while it remained unaltered in the epidural group (control; 66 (54-76), epidural; 43 (29-58) mg x kg(-1) x h(-1), P<0.05, median (range)). Glucose plasma concentration and Ra glucose increased in both groups to a similar extent (P<0.05). Plasma concentration of branched chain amino acids decreased after epidural analgesia to a value significantly lower than in the control group (P<0.05). Glutamine plasma concentration decreased in the control group (P<0.05), but did not change in the epidural group. There were no differences in plasma concentrations of insulin, cortisol and catecholamines between the two groups. Glucagon plasma concentration in the epidural group was significantly lower than in the control group (P<0.05). CONCLUSION: Intraoperative epidural blockade inhibits the increase in protein breakdown after abdominal surgery.

Abdomen↗