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PubMed1994

Characterization of prothrombin activation during cardiac surgery by hemostatic molecular markers.

BACKGROUND: Prothrombin activation represents the key regulatory step in the hemostatic process. Once formed, thrombin contributes to the generation of fibrin as well as the activation of platelets and fibrinolysis. Failure to suppress thrombin formation during cardiac surgery could result in disorders of hemostasis and thrombosis in the perioperative period. The aim of this study was to determine the time course for prothrombin activation during the perioperative period associated with cardiac surgery. METHODS: We measured prothrombin activation during the perioperative period in 19 adult patients undergoing primary cardiac surgery using enzyme-linked immunosorbent assays for the detection of thrombin formation (prothrombin fragment 1.2 and thrombin-antithrombin III complex) and thrombin activity (fibrinopeptide A and fibrin monomer). Blood samples were obtained preoperatively; at 30-min intervals during cardiopulmonary bypass (CPB); and 1, 3, and 20 h after completion of CPB. RESULTS: Despite anticoagulation with heparin, plasma concentrations of prothrombin fragment 1.2, thrombin-antithrombin III complex, and fibrin monomer increased throughout CPB. Peak concentrations for all hemostatic markers occurred in the samples obtained 3 h after completion of CPB. By the morning after surgery, plasma prothrombin fragment 1.2 returned to preoperative concentrations; however, fibrinopeptide A and fibrin monomer concentrations remained significantly increased (P < 0.05) compared to preoperative values. CONCLUSIONS: These data clearly demonstrate the occurrence of prothrombin activation and thrombin activity during CPB despite heparin concentrations adequate to maintain the activated clotting time greater than 400 s. Hemostatic markers for the activation of prothrombin demonstrated peak concentrations 3 h after completion of CPB with a return to baseline concentrations by the morning after surgery. Markers for thrombin activity, however, suggest the presence of active thrombin through the morning after surgery. Further investigations will be necessary to determine the role of hemostatic activation in thrombotic complications after cardiac surgery.

Aged↗
PubMed1998

Pharmacokinetic analysis of the effect of vecuronium in surgical patients: pharmacokinetic and pharmacodynamic modeling without plasma concentrations.

BACKGROUND: Methods of the kinetic analysis of vecuronium based on effect only were developed but have been limited by the short time period of the studies. Using a multicompartment model and sequential dosing, the authors studied the ability of tests to determine most pharmacokinetic and pharmacodynamic parameters of vecuronium without measuring plasma concentrations. METHODS: The time course of neuromuscular blockade by successive bolus doses of vecuronium was recorded using electromyography. Inhibition of neuromuscular transmission by vecuronium was modeled by a biexponential decline in the concentrations in the central compartment and first-order transfer between the central and the effect compartments responsible for the inhibition of the first (T1) and fourth (T4) responses to train-of-four stimulation. RESULTS: The time course of the effect of vecuronium was described well by the model. The mean half-lives of equilibration between plasma and the effect compartments to inhibit T1 and T4 were 2.5 and 3.2 min, respectively. The mean half-lives of distribution and elimination from the central compartment were 7.7 and 7.8 min, respectively. From the kinetic and dynamic parameters calculated after two and three doses, the time taken to recover to 50% of the maximal block of T1 was predicted for the succeeding dose. The mean prediction errors (100 x [absolute difference between actual and predicted times]/actual) were 13.6% (range, 0-40%) and 15% (range, 0-25%) after three and four doses, respectively. CONCLUSIONS: After sequential doses, measurement of the time course of the effect of vecuronium yields pharmacokinetic and pharmacodynamic parameters with clinically acceptable accuracy in individual patients.

Dose-Response Relationship, Drug↗
PubMed2004

Surgical site infection and the routine use of perioperative hyperoxia in a general surgical population: a randomized controlled trial.

CONTEXT: Surgical site infection (SSI) in the general surgical population is a significant public health issue. The use of a high fractional inspired concentration of oxygen (FIO2) during the perioperative period has been reported to be of benefit in selected patients, but its role as a routine intervention has not been investigated. OBJECTIVE: To determine whether the routine use of high FIO2 during the perioperative period alters the incidence of SSI in a general surgical population. DESIGN, SETTING, AND PATIENTS: Double-blind, randomized controlled trial conducted between September 2001 and May 2003 at a large university hospital in metropolitan New York City of 165 patients undergoing major intra-abdominal surgical procedures under general anesthesia. INTERVENTIONS: Patients were randomly assigned to receive either 80% oxygen (FIO2 of 0.80) or 35% oxygen (FIO2 of 0.35) during surgery and for the first 2 hours after surgery. MAIN OUTCOME MEASURES: Presence of clinically significant SSI in the first 14 days after surgery, as determined by clinical assessment, a management change, and at least 3 prospectively defined objective criteria. RESULTS: The study groups were closely matched in a large number of clinical variables. The overall incidence of SSI was 18.1%. In an intention-to-treat analysis, the incidence of infection was significantly higher in the group receiving FIO2 of 0.80 than in the group with FIO2 of 0.35 (25.0% vs 11.3%; P =.02). FIO2 remained a significant predictor of SSI (P =.03) in multivariate regression analysis. Patients who developed SSI had a significantly longer length of hospitalization after surgery (mean [SD], 13.3 [9.9] vs 6.0 [4.2] days; P<.001). CONCLUSIONS: The routine use of high perioperative FIO2 in a general surgical population does not reduce the overall incidence of SSI and may have predominantly deleterious effects. General surgical patients should continue to receive oxygen with cardiorespiratory physiology as the principal determinant.

Anesthesia, General↗
PubMed1983

Axillofemoral and femorofemoral grafts: a 6-year experience with emphasis on the relationship of peroperative flow measurement to graft survival.

Over a 6-year period 64 axillofemoral bypass and femorofemoral crossover grafts have been performed in 58 patients, most of whom were considered unfit for intra-abdominal surgery. Indications were peripheral ischaemia in 78 per cent and disabling claudication in 22 per cent. The limb salvage rate at 3 years was 75 per cent. No claudicants lost limbs, but only one-third of patients presenting with forefoot gangrene or ulceration avoided amputation. Most patients presenting with ischaemic symptoms at rest had associated femoropopliteal and distal disease, confirmed by the ankle pressure index measurements, and this influenced graft patency. Although the cumulative patency at 3 years for all grafts combined was 57 per cent with similar patencies for both the axillofemoral and femorofemoral grafts, early occlusion was more common in axillofemoral grafts and this may be reduced in bifemoral grafts by the increased flow rate in the vertical limbs. Peroperative electromagnetic flowmeter measurements were made after reconstruction on 55 femoral arteries in 46 of the patients and graft flow velocities were derived from these measurements. Comparison between velocities from those grafts remaining patent and those subsequently occluding showed a high incidence of occlusion in grafts with a maximal velocity after distal vasodilatation of less than 8 cm/s. Graft occlusion after the first postoperative month was more commonly associated with other factors such as continued smoking, severity of distal disease and perigraft infection.

Aged↗
PubMed2005

Bioelectric impedance and individual characteristics as prognostic factors for post-operative complications.

BACKGROUND AND AIMS: Malnutrition increases morbidity and mortality in surgical patients, and for this reason, several nutritional markers have been used as prognostic tools to identify surgical patients under a higher risk to develop complications in post-operative period. Few studies show the impact of nutritional markers after controlling for others variables, such as age and severity of disease. A new method, bioelectric impedance analysis (BIA), and its parameter, phase angle, have been described as a prognostic tool in several clinical situations, but they have never been studied in surgical population. The objective of this work is to assess the importance of nutritional variables and parameters from BIA as predictors of post-operative complications in a multivariable regression model. METHODS: The nutritional status of 225 adult patients scheduled to undergo gastrointestinal surgery was assessed by several methods, including bioelectric impedance analysis and subjective global assessment. Potential confounding factors were also studied. Patients were screened for post-operative complications until hospital discharge. RESULTS: Weight loss greater than 10%, subjective global assessment, nutritional risk assessment, ECM/BCM ratio and phase angle (from BIA) were the prognostic factors significantly associated with post-operative complications in the crude analysis. After adjusting for sex, age, marital status, tumors and pre-operative infections, only phase angle remained as a prognostic factor (RR=4.3; CI95% 1.6-11.8 for phase angle <-0.8 sd), while the other nutritional variables lost their association with post-operative complications. CONCLUSION: Phase angle remains as an important prognostic factor for postoperative complications, even after adjusting for other individual predictors and confounders. Its utility in the identification of patients eligible for nutritional therapy has now to be evaluated.

Adolescent↗
PubMed2005

Extra-pleural pneumonectomy for malignant pleural mesothelioma: the risks of induction chemotherapy, right-sided procedures and prolonged operations.

OBJECTIVE: With the increasing incidence of malignant pleural mesothelioma and renewed interest in radical surgery as a therapeutic option, we have examined our experience of extra-pleural pneumonectomy, to document the incidence and management of its peri-operative complications. METHODS: This analysis was conducted using prospectively entered data contained within the departmental database, with additional information from retrospective case note review. Details of patient selection criteria and operative modifications are included. RESULTS: Over a 59-month period, extra-pleural pneumonectomy was carried out on 74 patients (66 men; 8 women; median age 57 years). Fifteen patients (20%) received cisplatin-doublet induction chemotherapy. The majority (80%) of patients had epithelial tumours and 85% of patients had disease in International Mesothelioma Interest Group stages III and IV. The 30-day post-operative mortality was 6.75% (five patients) and significant morbidity was recorded in 47 patients (63%). Major complications included those of technical origin (diaphragmatic patch dehiscence 8.1%; chylothorax 6.7%; intra-thoracic haemorrhage 6.7%; bronchopleural fistula 6.7%), cardiovascular morbidity (atrial fibrillation 17.5%; mediastinal shift with subacute tamponade 10.8%; right ventricular failure 4%; pulmonary embolus 2.7%) and respiratory morbidity (pneumonia 10.8%; acute lung injury 8.1%). Admission to intensive care was required in 19 patients (26%). Univariate analysis identified the incidence of acute lung injury and mediastinal shift to be significantly associated with induction chemotherapy (P=0.005 and 0.014, respectively). In addition to this, laterality of operation influenced respiratory morbidity (P=0.018) and admission to intensive care (P=0.025). Finally, prolonged operations (greater than the median) were associated with an increased risk of technical (P=0.018) and gastro-intestinal (P=0.023) complications. CONCLUSIONS: Extra-pleural pneumonectomy is associated with a high rate of morbidity, but an acceptable mortality rate can be achieved with increasing peri-operative experience. Surgery following induction chemotherapy requires extra vigilance for the development of post-operative respiratory complications.

Adult↗
PubMed1997

Primary fibrinolysis during supraceliac aortic clamping.

PURPOSE: An increased incidence of bleeding complications has been observed after supraceliac aortic clamping (SCC). This study was performed to identify possible hemostatic abnormalities that contribute to this problem. METHODS: A prospective cohort study over a 3-month period was performed by comparing hemostatic parameters in 10 consecutive patients who required elective SCC with those of eight concurrent randomly selected control subjects who required infrarenal clamping (IRC) for abdominal aortic reconstruction. Measures of coagulation, fibrinolysis, platelet function, temperature, hemodilution, and hepatic function were performed at selected times before, during, and after operation. RESULTS: Aneurysm size, fibrinogen, D-dimers, prothrombin, partial thromboplastin time, platelet counts, bleeding times, hemodilution, and temperature were comparable in both groups. Patients in the SCC group, however, consistently developed a primary fibrinolytic state within 20 minutes after supraceliac clamping, reflected by significantly decreased euglobulin clot lysis times (ECLT; p < 0.0001), elevated tissue plasminogen activator (t-PA) levels (p < 0.0006), elevated t-PA-to-plasminogen activator inhibitor-1 ratios (p < 0.0001), and reduced alpha 2-antiplasmin levels (p < 0.002). SCC produced hepatocellular injury documented by elevations in both aspartate transaminase (p < 0.0001) and lactate dehydrogenase (p < 0.009). CONCLUSIONS: SCC rapidly induces a primary fibrinolytic state manifested by increased circulating t-PA, reduced alpha 2-antiplasmin, and increased fibrinolytic activator-to-inhibitor ratios. These effects may be a result of hepatic hypoperfusion caused by SCC leading to insufficient clearance of t-PA. Antifibrinolytic agents may be of benefit if bleeding develops after aortic procedures that require supraceliac clamping.

Aged↗
PubMedDate not supplied

Surgical reversal of two-kidney one clip hypertension during inhibition of the renin-angiotensin system.

Conscious rats with two-kidney one clip Goldblatt hypertension had the constricting clip removed during continuous infusion of either dextrose, saralasin, or captopril. Other dextrose-infused animals underwent removal of the ischemic kidney or a sham procedure. Direct arterial blood pressure (BP) was recorded throughout the 15-hour preoperative and subsequent 24-hour postoperative period. Rats were studied in the "early" phase (1-3 weeks duration) or "chronic" phase (greater than 4 months) of hypertension. Animals subjected to a sham procedure returned to preoperative BP values. The BP of animals unclipped or nephrectomized did not return to previous hypertensive levels. Instead, a biphasic response was seen where BP partially recovered from an operative fall and then slowly declined to normal at 24 hours; this effect occurred in both stages of hypertension. At 24 hours, removal of the ischemic kidney was as effective as removal of the constricting clip in the correction of both early and chronic phase hypertension. Rats infused with saralasin or captopril demonstrated an acute (within 2 hours) and sustained fall in BP, but not to normotensive levels. This fall was significant in all animals (p less than 0.01) apart from chronic phase rats infused with saralasin where no significant fall was seen. Although animals infused with saralasin or captopril commenced at a lower preoperative BP, the biphasic pattern of response to unclipping was identical to that of dextrose-infused unclipped rats. Thus, sustained inhibition of the renin-angiotensin system did not modify the correction of hypertension produced by removal of the constricting clip, and the response to surgical correction did not appear to be entirely mediated by changes in the activity of the renin-angiotensin system, particularly in the chronic stage. Equally, the rapidity of correction is not consistent with a role of vascular hypertrophy.

Animals↗
PubMed2006

Surgical treatment and clinical course of patients with hypopharyngeal carcinoma.

In the period between 1 January 1978 and 1 January 2004, 85 patients with hypopharyngeal squamocellular carcinoma were admitted at the Department of Esophagogastric Surgery in Belgrade. Among them, only 46 patients (54.1%) had radical surgical en-block resection and functional neck dissection, and they were included into an historical cohort study. In 40 patients a pharyngolaryngoesophagectomy was performed using for reconstruction, stomach tissue in 29 and colon tissue in 11 patients. Since 1996, in six patients with localized hypopharyngeal carcinoma pharyngolaryngectomy was performed with resection of cervical esophagus and free jejunal graft interposition. The overall incidence of morbidity was 50.0% and the overall mortality rate was 13.0% (6 patients). Mean hospital stay was 35 days (range, 18-78 days). The median survival of patients was 26 months, and overall 5-year survival rate was 26.5%. At present, surgery seems to be the appropriate therapeutic choice for patients with advanced hypopharyngeal carcinoma, providing a definitive palliation of dysphagia and relatively good long-term survival. At our Institution, after pharyngolaryngoesophagectomy, reconstructive method of choice is gastric 'pull-up', and the colon is used only when stomach tissue is not available, that is, previous gastric resections, inappropriate blood supply, synchronous gastric carcinoma and so on. Recently, pharyngolaryngectomy and free jejunal transfer has become the standard technique in patients with small carcinomas (up to 3 cm) confined to the hypopharynx in the absence of synchronous esophageal and/or gastric carcinoma.

Adult↗
PubMed2004

Risk stratification in paediatric open-heart surgery.

OBJECTIVE: The aims of this study were to identify independent risk factors for mortality following paediatric open-heart surgery and to develop risk models for use in clinical audit based on identified risk factors. The study also tests the validity of the recently proposed Risk Adjustment in Congenital Heart Surgery (RACHS-1) method of risk stratification as applied to open-heart operations. METHODS: A multiple logistic regression analysis was performed on all patients less than 18 years of age undergoing open-heart surgery at a single institution over a 3-year period. Preoperative and operative variables included for analysis were age at operation, weight, sex, American Society of Anaesthesiology (ASA) grade, RACHS-1 risk category, preoperative haemoglobin, bypass time, temperature, cross-clamp time, circulatory arrest time, blood transfusion on bypass and surgeon. The outcome measure was in-hospital death. RESULTS: 1085 consecutive open-heart cases were identified. There were 51 in-hospital deaths (4.7%). Variables identified as being independently significant risk factors for in-hospital death were age (P = 0.0002), RACHS-1 risk category (P < 0.0001), and bypass time. Based on these three variables, a risk model was constructed to predict mortality. The area under the receiver-operating-characteristic (ROC) curve for this model was 0.86. A second model was constructed ignoring bypass time. In this model, the significance of the 'preoperative' risk factors was (P = 0.0003) for age and (P < 0.0001), for RACHS-1 risk category. The area under the ROC curve was 0.81 for the second model. CONCLUSIONS: This study identifies age at operation, RACHS-1 risk category and bypass time as highly significant risk factors for mortality after paediatric open-heart surgery. It validates the RACHS-1 risk stratification method as applied to the subset of open-heart surgery, whilst accepting the limitations of such a system. The risk models formulated permit risk prediction and allow for analysis of surgical results. Such risk-adjustment is important when assessing performance and comparing outcomes amongst individuals or institutions.

Adolescent↗
PubMed2005

[Perioperative cortisol circadian secretion and neuropsychological states in patients undergoing coronary artery bypass grafting surgery].

OBJECTIVE: To investigate the relationship between the circadian rhythm of perioperative cortisol secretion and neuropsychological states in patients undergoing coronary artery bypass grafting surgery. METHODS: Forty male patients scheduled for elective coronary artery bypass grafting (CABG) under hypothermic cardio-pulmonary bypass (CPB) or off-pump were enrolled in this study. They were allocated into CPB group or off-pump group with 20 patients in each group. Blood samples were withdrawn during surgery at specific time-points and every 3 h for 24 h in the immediate postoperative period. Plasma cortisol was measured by radioimmunoassay. All subjects were investigated preoperatively as well as 7 to 10 d and 3 months postoperatively with a comprehensive neuropsychologic assessment, while depression and anxiety were assessed by Self-Rating Depression Scale and the State-Trait Anxiety Inventory respectively. RESULTS: During postoperative 24 h, three patients in the CPB group and 7 patients in the off-pump group were demonstrating a circadian secretion pattern, while they were disturbed in the remaining patients in both groups. Postoperative depression scores of patients in both groups were significantly higher than preoperative values. Postoperative anxiety scores of patients in the CPB group were significantly higher than those in the off-pump group. The CABG with CPB patients showed a significant deficit in the Digit Span subtest of the WAIS-R and the Stroop colour word interference test. The disturbed cortisol circadian secretion in the CPB group correlated with depression and the Stroop colour word interference test, whereas in the off-pump group it correlated with depression, Digit Span subtest (forward), symbol digit modalities test and the Stroop colour word interference test. Degree of depression correlated with some items of cognitive dysfunctions. CONCLUSION: Perioperative secretion rhythm of cortisol in patients undergoing CABG surgery with CPB or off-pump was disturbed. The disordered cortisol may correlate directly or indirectly through mood with neuropsychological deficits.

Cardiopulmonary Bypass↗
PubMed1997

The effect of preoperative recombinant human erythropoietin therapy on platelets and hemostasis in patients undergoing cardiac surgery.

In a double-blind, randomized, placebo-controlled trial we evaluated the effects of the administration of recombinant human erythropoietin (5 x 500 U epoetin beta/kg body weight intravenously over a 14-day period before surgery) in patients undergoing cardiac surgery and in whom autologous blood donation was contraindicated on platelet count, platelet distribution width, mean platelet volume (MPV), and certain hemostaseologic parameters. All patients received 3 x 70 IU heparin/kg per day s.c. from 2 days before operation. No thromboembolic events were associated with epoetin beta therapy during the study period. The thrombocytic parameters showed no significant changes in the placebo group before surgery, and the preoperative hematocrit increase in the epoetin beta group was accompanied with an MPV drop (in contrast to the known MPV rise in recombinant human erythropoietin-treated patients with uremia) by a mean of 0.85 fl and a platelet distribution width rise by 3.3% without a significant change in platelet count. In the epoetin beta group the coagulation time (K) of thromboelastogram (TEG) showed an increase from 4.8 to 5.4 minutes by the seventh study day and after the initiation of heparin therapy a further increase to 7.5 minutes. The higher preoperative K increase in the epoetin beta group may partly be a result of the MPV reduction, because smaller platelets are less reactive, a fact underlined by the negative correlation between the preoperative changes of MPV and reaction time of TEG (r = -0.58, p = 0.0148). In contrast, in the placebo group the K of TEG increased only after the start of heparin therapy (from 5.1 to 6.4 minutes). The significant drop in MPV in the epoetin beta group and the higher increase in K of TEG and the other investigated hemostatic parameters do not suggest any increased thromboembolic risk during the preoperative epoetin beta therapy. Therefore this treatment seems to be a safe way for increasing mean hematocrit by approximately 0.06 within the normal range and reducing the homologous blood requirement in patients undergoing elective cardiac surgery.

Adolescent↗
PubMed1996

[Augmented spontaneous breathing].

Impaired pulmonary gas exchange can result from lung parenchymal failure inducing oxygenation deficiency and fatigue of the respiratory muscles, which is characterized by hypercapnia or a combination of both mechanisms. Contractility of and coordination between the diaphragm and the thoracoabdominal respiratory muscles predominantly determine the efficiency of spontaneous breathing. Sepsis, cardiac failure, malnutrition or acute changes of the load conditions may induce fatigue of the respiratory muscles. Augmentation of spontaneous breathing is not only achieved by the application of different technical principles or devices; it also has to improve perfusion, metabolism, load conditions and contractility of the respiratory muscles. Intermittent mandatory ventilation (IMV) allows spontaneous breathing of the patient and augments alveolar ventilation by periodically applying positive airway pressure tidal volumes, which are generated by the respirator. Potential advantages include lower mean airway pressure (PAW), as compared with controlled mechanical ventilation, and improved haemodynamics. Suboptimal IMV systems may impose increased work and oxygen cost of breathing, fatigue of the respiratory muscles and CO2 retention. During pressure support ventilation (PSV), inspiratory alterations of PAW or gas flow (trigger) are detected by the respirator, which delivers a gas flow to maintain PAW at a fixed value (usually 5-20 cm H2O) during inspiration. PSV may be combined with other modalities of respiratory therapy such as IMV or CPAP. Claimed advantages of PSV include decreased effort of breathing, reduced systemic and respiratory muscle consumption of oxygen, prophylaxis of diaphragmatic fatigue and an improved extubation rate after prolonged periods of mechanical ventilation. Minimum alveolar ventilation is not guaranteed during PSV; thus, close observation of the patient is mandatory to avoid serious respiratory complications. Continuous positive airway pressure breathing (CPAP) maintains PAW above atmospheric pressure throughout the respiratory cycle, which may increase functional residual capacity and decrease the effort of breathing. CPAP has been conceptually designed for the augmentation of spontaneous breathing and requires the intact central and peripheral regulation of the respiratory system. Airway pressure release ventilation (APRV) improves alveolar ventilation by intermittent release of PAW, which is kept above atmospheric pressure by means of a high-flow CPAP system. The opening of an expiratory valve for 1-2 s induces a decreased PAW and lung volume, which increases rapidly to pre-exhalation values after closure of the valve due to the high gas flow within the circuit (90-100 1/min). APRV may improve haemodynamics and VA/Q distribution as compared with conventional mechanical ventilation. Biphasic positive airway pressure (BIPAP) is characterized by the combination of spontaneous breathing and time-regulated, pressure-controlled mechanical ventilation. During the respiratory cycle the ventilator generates two alternating CPAP levels, which can be modified with regard to time and pressure. As with APRV, alveolar ventilation is maintained even if the spontaneous breathing efforts of the patient cease, which improves the safety of both modes of respiratory therapy. The contribution of spontaneous breathing to total minute ventilation may be important, since a decreased shunt and improved VA/Q relationship have been observed in experimental non-cardiogenic lung oedema. These data give support to the concept that spontaneous breathing should be maintained and augmented in the setting of acute respiratory failure.

Humans↗
PubMed2005

Ocular-hypertensive response and corneal endothelial changes after intravitreal triamcinolone injections in Chinese subjects: a 6-month follow-up study.

PURPOSE: To assess the intraocular pressure (IOP) and corneal endothelial changes, over a 6-month period, after a single injection of intravitreal triamcinolone (ivTA) in Chinese patients. METHODS: A total of 43 eyes of 43 consecutive Chinese patients with various macular diseases received a single bolus injection of 4 mg ivTA, of which, 14 eyes with significant cataracts underwent simultaneous phacoemulsification and primary intraocular lens implantation. IOP was measured preoperatively and weekly in the first month, and then monthly until 6 months postinjection. Specular microscopy was performed on 24 of the 29 eyes without simultaneous cataract surgery, preoperatively and at months 1, 3, and 6. RESULTS: All patients completed 6 months of follow-up. Nine out of 43 (20.9%) eyes had IOP >21 mmHg. Their mean maximum IOP was 29.2 mmHg (range 23.0-37.0), necessitating the use of 2.0 types of topical antiglaucomatous medications on average. The IOP elevation occurred at a mean of 5.2 weeks (range 1-17) postinjection. All IOPs returned to normal, without additional antiglaucomatous medications, by 6 months. There was no statistically significant difference (paired t-test, P<0.05) in the corneal endothelial cell count and other specular microscopy parameters up to 6 months after the injections. CONCLUSION: A single 4 mg bolus injection of ivTA appeared to have no harmful effects on the corneal endothelium. IvTA caused transient IOP elevations in 20.9% of Chinese patients, similar to that observed in Caucasians. As the IOP rise can occur as early as 1 week after the injection, early monitoring will help its early detection and prevent optic nerve damage.

Adult↗
PubMed1993

Clinical significance of pulmonary aspiration during the perioperative period.

BACKGROUND: Pulmonary aspiration of gastric contents during the perioperative period may be associated with postoperative mortality or pulmonary morbidity. Recent determination of the incidence of perioperative pulmonary aspiration and evaluation of factors related to clinical outcomes is lacking. METHODS: We retrospectively reviewed the perioperative courses of 172,334 consecutive patients 18 yr of age or older who underwent 215,488 general anesthetics for procedures performed in all surgical specialties from July 1985 to June 1991. Pulmonary aspiration was defined as either the presence of bilious secretions or particulate matter in the tracheobronchial tree or, in patients who did not have their tracheobronchial airways directly examined after regurgitation, the presence of an infiltrate on postoperative chest roentgenogram that was not identified by preoperative roentgenogram or physical examination. RESULTS: Pulmonary aspiration occurred in 67 patients (1:3,216 anesthetics). Fifteen aspirations occurred in 13,427 (1:895) anesthetics of patients undergoing emergency surgery, and 52 occurred in 202,061 (1:3,886) anesthetics of patients undergoing elective surgery (P < .001). Of the 66 patients who survived their surgery, 42 (64%) did not develop a cough or wheeze, a decrease in arterial hemoglobin oxygen saturation while breathing room air > 10% less than the preoperative value, or radiographic abnormalities within 2 h of aspiration. These 42 patients had no respiratory sequelae. Of the 24 patients who had one or more of these findings, 13 required mechanical ventilatory support for more than 6 h. Three of the six patients whose lungs required mechanical ventilation for more than 24 h died from pulmonary insufficiency (overall mortality = 1:71,829 anesthetics). CONCLUSIONS: This study suggests that patients with clinically apparent aspiration who do not develop symptoms within 2 h are unlikely to have respiratory sequelae.

Adult↗
PubMed1999

Myocardial substrate uptake and oxidation during and after routine cardiac surgery.

OBJECTIVE: This study was designed to clarify whether myocardial substrate uptake and oxidation change after a period of hypothermic cardioplegic arrest during coronary artery bypass grafting procedures. METHODS: In 30 patients arterial and coronary sinus blood was sampled and coronary sinus flow measurements were performed before and after sternotomy and 10 minutes, 20 minutes, 50 minutes, and 6 hours after release of the aortic crossclamp. Measurement of free fatty acids, lactate, glucose, oxygen content, and carbon dioxide content in arterial and coronary sinus blood allowed calculations of myocardial substrate use, respiratory quotients, and myocardial oxidation rates of carbohydrates and fat. RESULTS: Uptake of free fatty acids and lactate was significant throughout the study and did not change in association with release of the crossclamp. Free fatty acid and lactate uptake measured 6 +/- 4 micromol/min and 23 +/- 26 micromol/min, respectively, before crossclamping compared with 8 +/- 7 micromol/min and 19 +/- 21 micromol/min, respectively, after release of the clamp. Glucose uptake was significant only during the first hour after crossclamp release and increased from 7 +/- 50 to 28 +/- 34 micromol/L after crossclamp release. Myocardial oxygen consumption did not change significantly (0.5 +/- 0.2 mmol/L compared with 0.35 +/- 0.2 mmol/L) after release of the crossclamp. Myocardial oxygen extraction ratio decreased from 58% +/- 8% to 41% +/- 13% after crossclamp release. Respiratory quotient increased after crossclamp release (0.85 +/- 0. 2 compared with 1.00 +/- 0.2), which implies that carbohydrate oxidation increased at the expense of free fatty acid oxidation. CONCLUSION: We conclude that hypothermic cardioplegic arrest during coronary artery bypass graft operations is associated with a transiently increased uptake and oxidation of carbohydrates during the immediate reperfusion phase.

Aged↗
PubMed1993

[20 years of mitral valve replacement. Development of a patient profile and operative mortality].

Between 1971 and 1991, 1,179 mitral valve replacements (MVR) were carried out in 1,134 patients. The sex ratio was stable over this period (0.7 men/women) whereas the average age of the patients increased by 10 years (50 years in 1971, 61 years in 1991). Since 1980, patients over 60 years of age represent about 60% and those over 70 years of age 16 to 22% of the population. The functional status of the patients has tended to be less severe, the NYHA stages III and IV which were initially preponderant, only represent 50 to 60% of patients operated nowadays. This reduction in the severity of symptoms is reflected in the average value of the cardio thoracic index which was 60 in 1971 and 54.8 in 1991. Similarly, the mean pulmonary artery pressures (measured in 823 patients, 69.8%) have decreased from 37.4 mmHg in 1971 to 29.9 mmHg in 1991. Rheumatic fever has tended to be replaced by degenerative etiologies which, since 1985, represent 40 to 50% of cases. Ischemic mitral regurgitation rare before 1980, is more common, presently making up 5 to 15% of MVR cases. In relation with the etiological changes mitral stenosis is giving way to mitral regurgitation as the commonest valve lesion (40 to 50% of cases in 1991). The annual operative mortality is lower (6 to 8%) than in 1982, despite the increasing number of emergency cases (7 to 10% of cases since 1985). The number of MVR with associated tricuspid valve repair has decreased with respect to isolated MVR or associated with aortocoronary bypass grafting. The only constant feature is the death rate due to myocardial dysfunction which remains over 50% whereas mortality related to the prosthetic valves varied over the years.

Age Factors↗
PubMed1996

Value of perioperative Doppler echocardiography in patients undergoing major lung resection.

BACKGROUND: The effects of major lung resection on right heart function have not been well established. Our goal was to evaluate these effects using serial Doppler echocardiography in the perioperative period. METHODS: In 86 patients undergoing lobectomy (n = 47) and pneumonectomy (n = 39), we examined the effects of pulmonary resection on perioperative changes in right heart function by transthoracic echocardiography. Serial echocardiograms were performed preoperatively, on postoperative day 1, and again between postoperative days 2 and 6 (median, 3 days) to evaluate cardiovascular function and to estimate right ventricular systolic pressure by the tricuspid regurgitation jet Doppler velocity method. RESULTS: Right or left atrial size, right atrial pressure, and estimated right ventricular systolic pressure did not differ between groups on the preoperative or postoperative day 1 examinations. However, on postoperative days 2 through 6 patients who underwent pneumonectomy had higher (mean +/- standard deviation) right ventricular systolic pressure values than lobectomy patients (31 +/- 15 versus 25 +/- 10 mm Hg, respectively; p < 0.05 by analysis of variance). In the subset of patients with percent predicted forced expiratory volume in 1 second less than 60% undergoing pneumonectomy (9/39), preoperative right ventricular systolic pressure was inversely correlated with percent predicted forced expiratory volume in 1 second values (r = -0.78; p < 0.04). This correlation was not significant in corresponding lobectomy patients. Postoperative right ventricular enlargement determined by echocardiography occurred with similar frequency in both groups and was associated with poor short-term prognosis in patients in whom severe respiratory failure developed. CONCLUSIONS: Preoperative indices of right heart function were within the normal range in both groups. Pneumonectomy but not lobectomy was associated with mild postoperative pulmonary hypertension that was not accompanied by significant right ventricular systolic dysfunction. Postoperative echocardiography may be useful to evaluate right heart function in critically ill patients after lung resection.

Adult↗