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Biomedical subjects

D C Cheng

Publications and source records attributed to D C Cheng.

At least 19 recordsLinked to original sources
PubMed2001

Clinical and echocardiographic diagnoses disagree in patients with unexplained hemodynamic instability after cardiac surgery.

PURPOSE: To investigate 1) if clinical indications match diagnostic findings from urgent transesophageal echocardiography (TEE) in hemodynamically unstable patients after cardiac surgery and 2) the clinical impact of the TEE findings. METHODS: Retrospective review of all postcardiac surgical intensive care patients who received an urgent TEE over a three- year period from July 1(st) 1997 until June 30(th) 2000. The clinician's presumed diagnosis based on hemodynamic and clinical evaluation was compared to TEE diagnosis. Surgical and medical interventions based on TEE results and the associated mortality were correlated. RESULTS: A hundred and thirty TEEs were performed for hemodynamic instability or suspected intracardiac vegetation or thrombus, all category I indications according to ASA guidelines. In 41.5% of patients the echocardiographic finding matched the presumed diagnosis. Patient management was significantly changed as a result of TEE findings in 58.5% of patients; 43.3% had changes in pharmacological therapy and 15.3% had a surgical intervention. Mortality was significantly lower in those who received a surgical intervention when compared to those who had changes in drug treatment (P <0.05). CONCLUSIONS: The results of urgent TEE in hemodynamically unstable patients or patients with thromboembolic phenomena in the postcardiac surgical intensive care unit are unpredictable in over half of cases. Inappropriate management decisions may result without the information obtained from TEE examination. Clinical management is often modified as a result of TEE findings. TEE is essential in the management of hemodynamically unstable postcardiac surgical patients.

Adult↗
PubMed2001

Computerized analysing system using the active contour in ultrasound measurement of carotid artery intima-media thickness.

BACKGROUND AND PURPOSE: B-mode measurement of the carotid intima-media (IM) thickness (T) based on manual tracing (MT) procedures are dependent on the subjectivity of the reader and the existing automatic tracing procedures often fail to detect the IM boundaries accurately. The purpose of this study was to compare the tracing results of the IM boundaries of the carotid wall with a new automatic identification (AI) procedure, based on an active contour model, and computer-assisted manual tracing (MT). METHODS: The detection of the IM boundaries was performed with both procedures in 126 ultrasound images [63 each of the common carotid artery (CCA) and carotid bulb] along the far wall of the distal CCA and the carotid bulb. Intra- and inter-reader variability for mean and maximum IMT with AI and MT and accuracy of identification of both IM boundaries were evaluated. RESULTS: Using MT the intra- and inter-reader variability amounted to 0.01-0.03 and 0.03-0.07 mm, respectively. The variability was slightly higher in the carotid bulb than in the CCA. Using AI the variability was almost eliminated. Mean and maximum IMT were measured systematically lower by AI compared with MT in all regions by 0.01 mm. The accuracy of identification was similar for both IM boundaries, but lower in the carotid bulb region than in the CCA. CONCLUSIONS: The new AI procedure identifies both IM boundaries in the region of the far wall of the CCA and carotid bulb with high precision, and eliminates most of the intra- and inter-reader variability of the IMT measurement using MT.

Adult↗
PubMed2001

Ultra-fast-track anesthetic technique facilitates operating room extubation in patients undergoing off-pump coronary revascularization surgery.

OBJECTIVE: To determine if implementation of ultra-fast-track anesthetic (UFTA) technique facilitates operating room extubation in patients undergoing off-pump coronary artery bypass graft (CABG) surgery. DESIGN: Retrospective review. SETTING: Referral center for cardiovascular surgery at a university hospital. PARTICIPANTS: Thirty-seven patients undergoing off-pump CABG surgery. INTERVENTIONS: Two groups represented UFTA (n = 10) and standard anesthetic (controls, n = 27) techniques. Anesthesia was conducted with propofol, remifentanil, vecuronium, and thoracic epidural analgesia in the UFTA group and thiopental, fentanyl, pancuronium, and isoflurane in the control group. Active temperature control was an integral part of the UFTA technique but not the standard technique. The active temperature control included intravenous fluid warmer, prewarmed skin preparation, humidified inspired gases, a circulating water warming blanket, and a forced-air warmer, along with the maintenance of the operating room temperature at 24 degrees C. The control group was managed with an intravenous fluid warmer, and the ambient temperature remained constant (20 degrees C). Patients who did not satisfy extubation criteria within 30 minutes from the end of surgery were sedated and transferred to the intensive care unit (ICU). MEASUREMENTS AND MAIN RESULTS: All patients in the UFTA group and 2 in the control group were extubated in the operating room immediately after surgery. None of the patients required reintubation. There was no significant difference in postextubation PaO(2) and PaCO(2) between the groups. Nasopharyngeal temperature decreased from 36.7 +/- 0.4 degrees C to 36.4 +/- 0.3 degrees C in the UFTA group and from 36.6 +/- 0.5 degrees C to 35.6 +/- 0.4 degrees C in the control group (p < 0.0001). Bradycardia occurred significantly more often in the UFTA group but there was no difference in episodes of hypotension. There were no perioperative deaths. Patients who were extubated in the operating room required lower nurse-to-patient acuity ratio (1:2) in the ICU. No difference was found in ICU and hospital length of stay. CONCLUSIONS: Implementation of UFTA technique provided adequate hemodynamic control and facilitated operating room extubation in all patients. The impact of UFTA on earlier patient discharge and actual cost savings within a fully integrated post-cardiac surgery unit requires further evaluation.

Aged↗
PubMed2001

Fast-track cardiac anaesthesia in the elderly: effect of two different anaesthetic techniques on mental recovery.

Elderly patients may be considered for 'fast-track' cardiac anaesthesia, but can suffer psychological complications and slow recovery of mental function after surgery, which can interfere with recovery. Reduced metabolism and changed distribution of anaesthetic and sedative agents can cause poor recovery. We made a prospective randomized comparison of mental function, haemodynamic stability and extubation and discharge times in elderly patients (65-79 yr) receiving two premedication, anaesthetic and sedative techniques. Patients received either propofol (n=39) (fentanyl 10-15 microg kg(-1) and propofol 2-6 mg kg(-1) intraoperatively and a propofol infusion for 3 h postoperatively) or premedication with lorazepam followed by midazolam for anaesthesia (n=39) (fentanyl 10-15 microg kg(-1) and midazolam 0.05-0.075 mg kg(-1) intraoperatively and a midazolam infusion for 3 h postoperatively). Impairment of mental function was noted in 41% of patients in the propofol group and 83% in the lorazepam and midazolam group (P=0.001) 18 h after extubation. Patients in the propofol group were extubated earlier [1.4 (SD 0.6) vs 1.9 (0.8) h, P=0.02]; and reached standard intensive care unit discharge criteria [7.6 (4.6) vs 14.2 (13) h, P=0.02] and hospital discharge criteria [4.3 (1.0) vs 4.9 (1.1) days, P=0.04) sooner than patients in the lorazepam and midazolam group, but actual discharge times did not differ between the groups. Haemodynamic values were stable in both groups.

Aged↗
PubMed2001

The effect of insulin cardioplegia on atrial fibrillation after high-risk coronary bypass surgery: a double-blinded, randomized, controlled trial.

UNLABELLED: Atrial fibrillation after coronary bypass (CABG) surgery is an important cause of morbidity and increased resource utilization. Insulin-enhanced cardioplegia may reduce postoperative arrhythmias by improving aerobic myocardial metabolism and mitigating the deleterious effects of ischemia. We performed a double-blinded, randomized, controlled clinical trial to determine if insulin-enhanced cardioplegia decreases the risk of post-CABG atrial fibrillation in a high-risk patient population. We randomized 501 patients undergoing urgent CABG to receive insulin-enhanced (Humulin R 10 IU/L, Insulin group, n = 243) or standard (Control group, n = 258) blood cardioplegia during cardiopulmonary bypass. Patients were monitored by using continuous electrocardiography for a minimum of 3 days postoperatively. All standard cardiac medications, including beta-adrenergic blockers, were continued postoperatively. Insulin-enhanced cardioplegia did not result in a significant reduction in postoperative atrial fibrillation. Furthermore, we failed to detect a difference in the incidence of conduction defects, ventricular tachycardia, or pacemaker requirements between insulin and placebo patients. Atrial fibrillation was the most common arrhythmia, occurring in 31% of all patients. Independent predictors of atrial fibrillation were elderly age, preoperative atrial fibrillation, and renal insufficiency. Right bundle branch block was the most common conduction abnormality. Predictors of right bundle branch block were elderly age, female sex, and circumflex coronary artery disease. The incidence of postoperative ventricular tachycardia, left bundle branch block, and permanent pacemaker requirement was small. We conclude that insulin-enhanced cardioplegia does not reduce the incidence of postoperative atrial fibrillation in high-risk CABG patients. IMPLICATIONS: We conducted a double-blinded, randomized, placebo-controlled trial of insulin-enhanced cardioplegia in 501 patients undergoing urgent coronary bypass surgery. Insulin did not decrease the incidence of postoperative atrial fibrillation when compared with placebo. We also failed to demonstrate a difference in the incidence of other postoperative arrhythmias between the two groups of patients.

Aged↗
PubMed2001

The efficacy and resource utilization of remifentanil and fentanyl in fast-track coronary artery bypass graft surgery: a prospective randomized, double-blinded controlled, multi-center trial.

UNLABELLED: We compared (a) the perioperative complications; (b) times to eligibility for, and actual time of the following: extubation, less intense monitoring, intensive care unit (ICU), and hospital discharge; and (c) resource utilization of nursing ratio for patients receiving either a typical fentanyl/isoflurane/propofol regimen or a remifentanil/isoflurane/propofol regimen for fast-track cardiac anesthesia in 304 adults by using a prospective randomized, double-blinded, double-dummy trial. There were no differences in demographic data, or perioperative mortality and morbidity between the two study groups. The mini-mental status examination at postoperative Days 1 to 3 were similar between the two groups. The eligible and actual times for extubation, less intense monitoring, ICU discharge, and hospital discharge were not significantly different. Further analyses revealed no differences in times for extubation and resource utilization after stratification by preoperative risk scores, age, and country. The nurse/patient ratio was similar between the remifentanil/isoflurane/propofol and fentanyl/isoflu-rane/propofol groups during the initial ICU phase and less intense monitoring phase. Increasing preoperative risk scores and older age (>70 yr) were associated with longer times until extubation (eligible), ICU discharge (eligible and actual), and hospital discharge (eligible and actual). Times until extubation (eligible and actual) and less intense monitoring (eligible) were significantly shorter in Canadian patients than United States' patients. However, there was no difference in hospital length of stay in Canadian and United States' patients. We conclude that both anesthesia techniques permit early and similar times until tracheal extubation, less intense monitoring, ICU and hospital discharge, and reduced resource utilization after coronary artery bypass graft surgery. IMPLICATIONS: An ultra-short opioid technique was compared with a standard fast-track small-dose opioid technique in coronary artery bypass graft patients in a prospective randomized, double-blinded controlled study. The postoperative recovery and resource utilization, including stratification of preoperative risk score, age, and country, were analyzed.

Aged↗
PubMed2001

Safety and efficacy of o-raffinose cross-linked human hemoglobin (Hemolink) in cardiac surgery.

PURPOSES: There are currently two major classes of oxygen therapeutics: hemoglobin based oxygen carriers (HBOCs) and synthetic perfluorocarbons (PFCs). This review focuses on the use of o-raffinose cross-linked human hemoglobin (Hb raffimer) in cardiac surgery. SOURCE: The literature on HBOCs was reviewed and the development and clinical trials on Hb raffimer were outlined. PRINCIPAL FINDING: The benefits of HBOCs include avoidance of known viruses, pathogens and cross-matching; increased stability and storage time; and efficient oxygen delivery to tissues. The limitations of HBOCs include binding the endogenous vasodilator, nitric oxide, thereby resulting in transient hypertension, esophageal dysfunction and abdominal discomfort. The short half-lives of these products makes them best suited to situations of acute anemia. Hb raffimer is prepared from outdated red blood cells, cross-linked with o-raffinose, a polyaldehyde obtained through the oxidation of the trisaccharide raffinose. The Hb is covalently cross-linked (beta-beta) within the 2,3 DPG binding pocket to form a stable 64 kDa tetramer. At this time, a total of over 500 patients have been enrolled and more than 300 patients have been treated with Hb raffimer. Preliminary analysis of data from recent Phase II & III clinical trials of Hb raffimer in routine coronary artery bypass grafting surgery suggest that the product is well tolerated and may facilitate avoidance of allogeneic blood product transfusion in this surgical setting. CONCLUSION: The converging evidence from clinical studies with HBOCs has demonstrated that these products have the potential to provide hemoglobin and oxygen carrying capacity to tissues in times of acute anemia during surgery. It is anticipated that Hb raffimer will be used to facilitate intraoperative autologous donation and emerge as an important alternative to allogeneic blood transfusion during cardiac surgery.

Cardiac Surgical Procedures↗
PubMed2000

Non-steroidal anti-inflammatory drugs in treatment of postoperative pain after cardiac surgery.

PURPOSE: Non-steroidal anti-inflammatory drugs (NSAIDs) are used as analgesic in postoperative pain to reduce opioid side effects, such as drowsiness and nausea. However, NSAIDs have not been used extensively in cardiac surgical patients due to the fear of untoward effects on gastric, renal, and coagulation parameters. This study will evaluate the efficacy and safety of three NSAIDs for pain control in CABG patients. METHODS: One hundred and twenty patients scheduled for elective CABG surgery were enrolled in randomized, double blind, controlled study. Standardized fast track cardiac anesthesia was used. One dose of drug (75 mg diclofenac, 100 mg ketoprofen, 100 mg indomethacin, or placebo) was given pr one hour before tracheal extubation and a second dose 12 hr later. Pain was treated with morphine iv and acetaminophen po. Visual analogue pain scores were recorded at baseline, 3, 6, 12 and 24 hr after the first dose of drug. RESULTS: There were no differences among the groups in pain scores. Only patients who received diclofenac required less morphine than patients in the control group (P < 0.05). When the total amounts of pain medications were computed to morphine equivalents, only patients in the diclofenac group received less pain medications than the placebo group (P < 0.05). Proportion of patients with postoperative increase of creatinine level (20% and over) did not differ between placebo and drug groups. CONCLUSION: Non-steroidal anti-inflammatory drugs may be used for analgesia management post CABG surgery in selected patients. Diclofenac appears to have the best analgesic effects by reducing the morphine and other analgesic requirement postoperatively.

Aged↗
PubMed1999

Morbidity outcome in patients with hypertrophic obstructive cardiomyopathy undergoing cardiac septal myectomy: early-extubation anesthesia versus high-dose opioid anesthesia technique.

OBJECTIVE: Anesthetic management of patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing septal myectomy is challenging. The morbidity outcome of early-extubation anesthesia (EEA), or fast tracking, versus high-dose opioid (HDO) anesthesia was studied. DESIGN: Retrospective study. SETTING: University teaching hospital. PARTICIPANTS: One hundred seventy-five cardiac septal myectomy patients (EEA, n = 53; HDO, n = 122). INTERVENTIONS: EEA technique consisted of low-dose fentanyl, 10 to 15 microg/kg; propofol infusion; midazolam; and inhalation agent. HDO technique consisted of fentanyl, 50 to 100 microg/kg, and benzodiazepines, with or without an inhalation agent. Demographic data, preoperative symptoms, and data on anesthesia management and postoperative complications were recorded. MEASUREMENTS AND MAIN RESULTS: There were no differences between the groups (EEA v HDO, respectively) regarding age, sex, preoperative symptoms (dyspnea, 89% v 79%; palpitations, 28% v 26%; angina, 47% v 61%; syncope, 47% v 41%), redo surgery, or combined surgery. Mean +/- standard deviation time to tracheal extubation was 7.2 +/- 5.3 hours in EEA versus 19.4 +/- 10.5 hours in HDO patients (p < 0.0001). Intensive care unit (ICU) stay was significantly shorter in EEA versus HDO patients (2.2 v 3.0 days; p < 0.005), with the trend toward earlier hospital discharge (9.7 v 11.3 days; p = 0.09). There was a high requirement for temporary pacing in both groups immediately postoperatively (EEA, 60% v HDO, 48%; p > 0.08). Permanent pacemaker insertion postoperatively was required in 7 of 53 patients (13%) in the EEA group and 11 of 122 patients (9%) in the HDO group (p > 0.25). Atrial arrhythmias occurred postoperatively in 25% of EEA patients versus 34% of HDO patients (p > 0.08). CONCLUSION: EEA facilitates earlier tracheal extubation by 12 hours in patients with HOCM undergoing septal myectomy, significantly shortening ICU stay by 1 day without increasing perioperative cardiac morbidity or mortality.

Adjuvants, Anesthesia↗
PubMed1999

Fast-track cardiac anesthesia in patients with sickle cell abnormalities.

UNLABELLED: We conducted a retrospective review of 10 patients with sickle cell trait (SCT) and 30 patients (cohort control) without SCT undergoing first-time coronary artery bypass graft surgery with cardiopulmonary bypass. Demographic, perioperative management, and outcome data were collected. Both groups were matched according to age, weight, duration of surgery, and preoperative hemoglobin (Hb) concentration. Distribution of gender, medical conditions, pharmacological treatment, and preoperative left ventricular function were similar between the groups. The comparisons were analyzed in respect to postoperative blood loss and transfusion rates, as well as duration of intubation, intensive care unit, and hospital length of stay (LOS). All patients underwent fast-track cardiac anesthesia. A combination of cold crystalloid and blood cardioplegia was used. The lowest nasopharyngeal temperature was 33 degrees C. There were no episodes of significant hypoxemia, hypercarbia, or acidosis. None of the patients had sickling crisis during the perioperative period. The postoperative blood loss was 687 +/- 135 vs 585 +/-220 mL in the SCT and control groups, respectively. The trigger for blood transfusion during cardiopulmonary bypass was hematocrit <20% and Hb <75 g/L postoperatively. Three SCT patients (30%) and 10 control patients (33%) received a blood transfusion. Median extubation time was 4.0 vs 3.9 h; intensive care unit LOS was 27 vs 28 h; and hospital LOS was 6.0 vs 5.5 days in the SCT and control groups, respectively. There were no intraoperative deaths. One patient in the SCT group died from multiorgan failure 2 mo after surgery. IMPLICATIONS: Fast-track cardiac anesthesia can be used safely in patients with sickle cell trait undergoing first-time coronary artery bypass graft surgery. Extubation time and intensive care unit and hospital length of stay are comparable to those of matched controls, and blood loss and transfusion requirements are not increased. A hematocrit of 20% seems to be a safe transfusion trigger during cardiopulmonary bypass in these patients.

Adult↗
PubMed1999

Risk factors of delayed extubation, prolonged length of stay in the intensive care unit, and mortality in patients undergoing coronary artery bypass graft with fast-track cardiac anesthesia: a new cardiac risk score.

BACKGROUND: Risk factors of delayed extubation, prolonged intensive care unit (ICU) length of stay (LOS), and mortality have not been studied for patients administered fast-track cardiac anesthesia (FTCA). The authors' goals were to determine risk factors of outcomes and cardiac risk scores (CRS) for CABG patients undergoing FTCA. METHODS: Consecutive CABG patients undergoing FTCA were prospectively studied. Outcome variables were delayed extubation > 10 h, prolonged ICU LOS > 48 h, and mortality. Univariate analyses were performed followed by multiple logistic regression to derive risk factors of the three outcomes. Simplified integer-based CRS were derived from logistic models. Bootstrap validation was performed to assess and compare the predictive abilities of CRS and logistic models for the three outcomes. RESULTS: The authors studied 885 patients. Twenty-five percent had delayed extubation, 17% had prolonged ICU LOS, and 2.6% died. Risk factors of delayed extubation were increased age, female gender, postoperative use of intraaortic balloon pump, inotropes, bleeding, and atrial arrhythmia. Risk factors of prolonged ICU LOS were those of delayed extubation plus preoperative myocardial infarction and postoperative renal insufficiency. Risk factors of mortality were female gender, emergency surgery, and poor left ventricular function. CRSs were modeled for the three outcomes. The area under the receiver operating characteristic curve for the CRS-logistic models was not significantly different: 0.707/0.702 for delayed extubation, 0.851/0.855 for prolonged ICU LOS, and 0.657/0.699 for mortality. CONCLUSION: In CABG patients undergoing FTCA, the authors derived and validated risk factors of delayed extubation, prolonged ICU LOS, and mortality. Furthermore, they developed a simplified CRS system with similar predictive abilities as the logistic models.

Aged↗
PubMed1999

Gas exchange and hemodynamics in experimental pleural effusion.

OBJECTIVE: To investigate the cardiorespiratory effects of graded bilateral pleural effusions in the anesthetized pig. DESIGN: Prospective, randomized, controlled, laboratory study. SETTING: Animal laboratory. SUBJECTS: Eleven male Yorkshire pigs. INTERVENTIONS: Animals were anesthetized using inhaled isoflurane. Orotracheal intubation was followed by mechanical ventilation. Bilateral chest tubes were inserted, and graded increasing pleural effusions were created using saline of 0, 20, 40, and 80 mL/kg, divided equally between each side. At each pleural volume, intravascular volume was randomly altered (by phlebotomy or transfusion of colloid) to normal (unchanged), low (decreased by 10 mL/kg), or high (increased by 10 mL/kg). MEASUREMENTS AND MAIN RESULTS: Hemodynamic parameters, intrapleural pressures, hemoglobin, and blood gases were measured. At the lowest volume of pleural fluid, PaO2 was reduced by approximately 50% vs. baseline, whereas systemic hemodynamics were unchanged. PaO2 was reduced in a dose-dependent fashion as pleural volume increased but was not affected by alterations in intravascular volume. Intrapulmonary shunt was increased both by intrapleural volume in a dose-dependent fashion and by increases in intravascular volume at high levels of pleural volume. Cardiac output and systemic mean arterial pressure increased with elevated intravascular volume but were not influenced by lower levels of intrapleural volume. Mean pulmonary arterial pressure, central venous pressure, and pulmonary artery occlusion pressure were increased by elevations in both intrapleural volume and intravascular volume. Intrapleural pressure and pulmonary vascular resistance were related to intrapleural volume only. CONCLUSIONS: Hypoxemia occurs as an early event in acute bilateral pleural effusions and precedes hemodynamic decompensation. Oxygenation is independent of intravascular filling pressures, but hemodynamics are preserved with elevated filling pressures. Clinical studies should be undertaken to examine the risks/benefits of careful removal of pleural fluid in patients with pleural effusions, when oxygenation is impaired during mechanical ventilation.

Anesthesia, Inhalation↗
PubMed1999

Structural models for intermediate care areas.

OBJECTIVE: To describe structural models of intermediate care units used for critically ill patients. DATA SOURCES: Three multidisciplinary units with varying structures and functions of intermediate care areas (ICAs) are described. DATA SYNTHESIS: Advantages and limitations for each of the three models are outlined. The structural models described are the conventional isolated ICA model, the parallel model, and the integrated model of ICA. CONCLUSION: Each structural model has advantages and limitations. Selection of the appropriate ICA model for an institution depends on the specific circumstances and needs of the institution. Each of the three models can facilitate improved utilization of critical care resources.

Critical Illness↗
PubMed1999

Acute graded hypercapnia increases collateral coronary blood flow in a swine model of chronic coronary artery obstruction.

OBJECTIVE: To evaluate the effect of acute hypercapnia on regional myocardial blood flow in a swine model of chronic, single-vessel coronary artery obstruction. Permissive hypercapnia is being used frequently in critical care settings. One possible detrimental effect of hypercapnia is the initiation of coronary "steal" in patients with coronary artery disease. The effects of hypercapnia on collateral coronary blood flow in the setting of coronary obstruction have not been defined. DESIGN: Prospective controlled experimental study. SETTING: Institutional animal research facility. SUBJECTS: Eight juvenile swine weighing 25-30 kg. INTERVENTIONS: Collateral coronary circulation was induced in eight piglets by banding the proximal left anterior descending coronary artery for 8-10 wks followed by total ligation. Graded hypercapnia (mean Paco2, 81 torr [10.80 kPa; Paco2 = 81 torr] and 127 torr [16.93 kPa; Paco2 = 127 torr]) was induced by increasing inspiratory carbon dioxide under isoflurane anesthesia (1 minimum alveolar concentration). MEASUREMENTS AND MAIN RESULTS: Animals were attached to instruments to measure pulmonary and systemic hemodynamics, regional myocardial blood flow, and cardiac output. Regional myocardial blood flow was determined using radiolabeled microspheres. Cardiac output, mean arterial pressure, and coronary perfusion pressure were unchanged at both levels of hypercapnia compared with baseline values. Heart rate was increased at Paco2 [HI] (p < .05). Regional blood flow was increased at both levels of hypercapnia in the collateral-dependent and normally perfused myocardium (p < .05; as high as 56% for subendocardium and as high as 106% for subepicardium at Paco2 [HI]). The intercoronary blood flow ratio remained unaltered. The transmural flow ratio was reduced at Paco2 [HI] (P < .05). During hypercapnia, regional lactate extraction remained unaltered, and regional oxygen extraction was unchanged or reduced despite the increase in oxygen consumption. CONCLUSIONS: In this swine model of chronic single-vessel coronary artery obstruction, acute hypercapnia does not induce coronary steal from collateral-dependent myocardium, but it does increase global coronary blood flow.

Animals↗
PubMed1998

Fast-track cardiac surgery: economic implications in postoperative care.

Economics is the main driving force in changing health care delivery in the 90s. The motto is to "do more with less." Cost containment and efficient resource utilization swing the pendulum back to the debate of early tracheal extubation in cardiac surgical patients. Recently, it has been confirmed that fast-track cardiac anesthesia is both safe and cost-effective. This article describes the economic implications in postoperative care of fast-track cardiac surgery. First, the developments of early extubation postcardiac surgery and the factors that influence costs of cardiac surgery are reviewed. Second, the morbidity outcome, utilization, and cost implications of early extubation in cardiac surgery are summarized. The perioperative cost analysis in fast-track cardiac surgery, including the cost of complications and resource utilization, is outlined. Lastly, it is important to realize that early extubation does not necessarily mean earlier intensive care unit or hospital discharge. To achieve a maximum cost benefit from early extubation, team organization of a fast-track cardiac surgery program for the perioperative management of these patients is detailed.

Anesthesia↗