Taras Mycyk

Respiratory function after cardiac surgery

STUDY OBJECTIVE Cardiac surgery is complicated by decreased postoperative respiratory muscle strength and spirometry with accompanying increased atelectasis. The specific respiratory symptoms attributable to these physiologic changes are unknown, and this study looked at the symptoms and underlying physiology. DESIGN Convenience sampling of observational cohort. SETTING Tertiary care university hospital. PATIENTS One hundred thirty-eight patients undergoing elective surgery were enrolled. INTERVENTIONS Changes from admission to 8-week postoperative values in atelectasis, pleural effusions, spirometry (forced vital capacity and forced expiratory volume in one second), and respiratory muscle strength (negative inspiratory pressure) were measured. These physiologic changes were compared with changes in respiratory symptoms of cough, wheeze, phlegm, and dyspnea on walking up a slight hill noted from admission to 8-week follow-up by stepward logistic regression. MEASUREMENTS AND RESULTS Spirometry and negative inspiratory pressure decreased and atelectasis increased from admission to discharge. These disturbances had only incompletely resolved at 8-week follow-up. Some patients reported fewer symptoms of cough (11%), phlegm (9%), wheeze (35%), and dyspnea (46%) at 8 weeks follow-up. Other patients reported increased symptoms of cough (15%), phlegm (10%), wheeze (6%), and dyspnea (4%) at 8 weeks follow-up. Residual atelectasis at 8 weeks was predictive of fewer symptoms of dyspnea (odds ratio [OR] 0.335, p = 0.199; 95% confidence interval [CI] 0.188, 0.597), increased symptoms of dyspnea (OR 855, p = 0.006; 95% CI 6.6, 11052), and increased symptoms of cough (OR 260, p = 0.023; 95% CI 2.13, 31829). Negative inspiratory pressure at 8 weeks was predictive of fewer symptoms of dyspnea (OR 1.05, p = 0.032; 95% CI 1.02, 1.09) and increased symptoms of wheeze (OR 0.7, p = 0.45; 95% CI 0.533, 0999). Forced vital capacity at 8 weeks was predictive of increased symptoms of wheeze (OR 0.005; p = 0.015; 95% CI 0.0060, 0.775). CONCLUSIONS Postoperative changes in respiratory muscle strength and spirometry can persist up to at least 8 weeks postoperatively. Many patients report a change in respiratory symptoms of cough, phlegm, dyspnea, or wheeze. The change in respiratory symptoms at 8 weeks is correlated with residual respiratory muscle weakness, decrease in spirometry, and residual atelectasis.

Depletion of activated neutrophils by a filter during cardiac valve surgery.

PurposeTo determine whether inclusion of a neutrophil-specific filter into the extracorporeal circuit during open heart valve surgery alters postoperative outcomes.MethodsConvenience sampling of 24 patients undergoing elective open heart valve surgery between July 1993 and June 1994. Patients were randomized to a neutrophil-specific filter (n= 11) or to a standard blood filter (n= 13) during cardiopulmonary bypass.ResultsNeutrophil-specific filter diminished (P < 0.02) the expression of CD 18, a neutrophil surface adhesion molecule, at 1 (84.5 ± 4.2 vs 94.8 ± 3.8%). 4 (80.0 ± 4.2 vs 95.1 ± 3.9%) and 24 hr (75.2 ± 4.2 vs 98.2 ±3.9%) post-operatively compared with standard filter. Total white blood cell count, neutrophil count, and proinflammatory cytokmes (IL-6, IL-8) were similar between groups at all times. Measured outcomes including: PaO2, cardiac index, ejection fraction, haemodynamic variables, use of motropes, spirometry (FEV FVC). and hospitalization duration were similar between groups.ConclusionsInclusion of the neutrophil filter during open heart valve surgery selectively depletes activated neutrophils. There were no other detectable differences between the two groups and the use of a neutrophilspecific filter in routine clinical practice for patients undergoing open heart valve surgery is not supported.RésuméObjectifDéterminer si l’ajout au circuit extracorporel d’un filtre spécifique aux neutrophiles pendant une chirurgie valvulaire modifiait les résultats de l’interventionMéthodesUn échantillonnage de 24 patients subissant une intervention valvulaire à coeur ouvert entre juillet 1993 et juin 1994. Les patients ont été répartis aléatoirement à un circuit extracorporel incluant un filtre spécifique aux neutrophiles (n= 11) ou un filtre standard (n= 13).RésultatsLe filtre spécifique aux neutrophiles a diminué l’expression de CD 18. une molécule adhésive de sur face, une heure (84.5 ± 4.2 vs 98.8 ± 3.8%), quatre heures (80 ± 4,2 vs 95.1 ± 3,9%) et 24 heures (75.2 ± 4,2 vs 98.2 ± 3.9%) après l’opération comparativement au filtre standard. Le décompte total des globules blancs, des neutrophiles et des cytokines pro-inflammatoires (IL-6. IL8) étaient à tous les moments identiques entre les groupes. Les mesures de résultats incluant la PaO2, l’index cardiaque, la fraction d’éjection, les données hémodynamiques, l’utilisation d’inotropes, la spirométne (VEMS, CVF) et la durée du séjour hospitalier étaient identiques entre les groupes.ConclusionL’ajout d’un filtre spécifique aux neutrophiles pendant la chirurgie à coeur ouvert épuise sélectivement les neutrophiles activés. Aucune autre différence n’est discernable entre les groupes. L’utilisation courante de filtres spécifiques aux neutrophiles en clinique chez des patients soumis à une chirurgie valvulaire à coeur ouvert n’est pas justifiée.

The impact of different biocompatible coated cardiopulmonary bypass circuits on inflammatory response and oxidative stress

This study was to compare the impact of different biocompatible coated circuits on inflammatory response and oxidative stress induced during cardiopulmonary bypass (CPB). Seventy-eight patients undergoing elective coronary artery bypass grafting (CABG) with CPB were randomly assigned to five groups with different biocompatible coated circuits: Trillium, Bioline, Phosphorylcholine, Polymethoxyethyl acrylate (PMEA), and the uncoated control group. Blood was drawn at three different time points: before CPB, 6 and 72 hours post CPB. Unlike the Trillium group, serum levels of TNF-α in the Bioline and Phosphorylcholine groups significantly increased only at 72 hours post CPB (p < 0.05). Serum levels of IL-6 significantly increased at 6 and 72 hours post CPB in all groups (p < 0.01). The Trillium group showed a significant increase of IL-10 compared to the control group at 72 hours post CPB (p < 0.05). Serum levels of NOx in the Phosphorylcholine group significantly decreased at 6 hours post CPB compared to baseline (p < 0.05). Both the Bioline and Phosphorylcholine groups showed statistical decreases in serum NOx levels compared with other groups at 6 hours post CPB (p < 0.05). A significant difference in NOx levels between the Bioline and the control group was also observed at 72 hours post CPB. Myeloperoxidase levels were significantly elevated at 6 and 72 hours post CPB in all groups (p < 0.05). Inflammatory response and oxidative stress are elevated during CABG with CPB. Heparin-coated and the Phosphorylcholine-coated circuits induce less inflammatory responses and oxidative stress compared to other circuits.

Outcomes comparison of 5 coated cardiopulmonary bypass circuits versus an uncoated control group of patients undergoing cardiac surgery

Attenuated inflammatory response and decreased platelet activation have been claimed repeatedly when biocompatible circuits are used for cardiopulmonary bypass. We evaluated five Health Canada approved biocompatible circuit coatings (BCC) against an un-coated control group to determine their effectiveness in improving post-operative outcomes. Patients were assigned to the Control group or one of the 5 coated circuit groups: 40 Control; 33 Trillium; 32 Phisio; 34 Bioline; 33 X; and 11 GBS. Measured outcomes included: ventilator time; ICU time; post-operative chest tube drainage and transfusion volume; high sensitivity C-reactive protein (hsCRP); tau protein; and pre- and 72-hour post-operative anti-saccadic eye movement test comparisons. Results: 183 patients were enlisted into the study. One arm of the study (GBS) was abandoned after 11 patients on account of inconsistent pressure excursions within the oxygenator and the excessive consumption of platelets necessitating transfusion. Patients in the X-coated group had significantly longer ventilator and intensive care unit (ICU) time compared to the three remaining coated circuit study groups. Though not significant, patients in the X group also demonstrated the highest post-operative chest tube losses, the most platelet transfusions, the highest tau protein levels and the lowest post-operative anti-saccadic eye movement test (ASEMT) results compared to the three remaining coated groups. The patients in the Trillium, Bioline and Phisio groups showed an improvement in ventilator and ICU time relative to the Control group. The diabetic patients in the Trillium, Bioline and Phisio groups showed an improvement in bleeding relative to the diabetic patients in the Control group. Conclusion: We compared all 5 coated circuits approved for clinical use in Canada against an uncoated control circuit. Three of the 5 coated circuits (Trillium, Phisio and Bioline BCC) were found to improve ventilator and ICU time compared to Control. Further studies are indicated to validate these results and their impact upon approval criteria, purchasing choices and safe clinical practice, especially as applied to higher risk diabetic patients.

A comparison of intra-operative cell-saving strategies upon immediate post-operative outcomes after CPB-assisted cardiac procedures

Cardiotomy suction has been associated with adverse outcomes under routine conditions in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). We hypothesized that the routine use of a cell saver (CS) in place of the cardiotomy sucker would have no negative impact on transfusion rate (TR), chest tube drainage (CTD), ventilation time (VT) or intensive care unit length of stay (ICULOS) while avoiding the detrimental effects of cardiotomy suction. Retrospective data were collected from 69 patients where a cell saver was not used (NCS). Prospective data were collected from 219 patients who were followed after the implementation of an intra-operative cell saver. No significant increase in transfusion rate, chest tube drainage or ventilation time was found between the NCS group and the CS group. However, post-operative hemoglobin concentrations were significantly higher in the CS group (0.0001) and the CS group spent significantly less time in the ICU (p=0.018).

CPB-assisted aortic valve replacement in a pregnant 27-year-old with endocarditis

A 27-year-old, G3P 2A0 female with acute Staph aureus (SA) endocarditis successfully underwent CPB-assisted aortic valve replacement with a bioprosthetic aortic valve at 22 weeks’ gestation. This patient’s presentation of acute endocarditis complicated by septic shock, congestive heart failure, severe aortic insufficiency, multiple septic embolic events and borderline renal failure appeared on the daunting background of chronic heavy tobacco usage, hepatitis C positivity, long-term IV drug abuse and a pregnancy into its twenty-second week. Optimal treatment strategies implemented for both mother and fetus throughout the perioperative period contributed to a successful outcome for both.

Outcomes and Biochemical Parameters Following Cardiac Surgery: Effects of Transfusion of Residual Blood Using Centrifugation and Multiple-Pass Hemoconcentration

OBJECTIVES To determine whether or not there was a significant difference between the methods of centrifugation (CF) and multiple-pass hemoconcentration (MPH) of the residual cardiopulmonary-bypass volume in relation to biochemical measurements and patient outcomes. DESIGN Prospective, randomized, and controlled. SETTING Conducted at a western Canadian tertiary care hospital. PARTICIPANTS Consisted of 61 consecutive male and female patients from ages 40 to 80 who were scheduled for cardiac surgery with cardiopulmonary bypass. INTERVENTIONS Either the centrifugation or multiple-pass hemoconcentration method was used to process the residual blood from the cardiopulmonary bypass circuit. RESULTS The 12-hour postoperative levels of serum hemoglobin were not significantly different in the centrifugation group as compared to the multiple-pass hemoconcentration group. However, the serum levels of total protein and albumin were significantly higher in the multiple-pass hemoconcentration group as compared to the centrifugation group. Additionally, after 12-hours postoperatively, the serum fibrinogen and platelet counts were significantly higher in the multiple-pass hemoconcentration group as compared to those of the centrifugation group. The allogeneic product transfusion index and the chest-tube blood drainage indices were lower in the multiple-pass hemoconcentration group as compared to the centrifugation group. CONCLUSION Although the CF method provided a product in a shorter turnaround time, with consistent clearance of heparin, the MPH method trended towards enhanced biochemical and clinical patient outcomes over the 12-hour postoperative period.

Dual-route tranexamic acid to reduce blood loss in coronary artery bypass graft surgery: a randomized controlled trial

To the Editor, A 2009 systematic review and meta-analysis suggested that topical anti-fibrinolytic agents can reduce postoperative bleeding and transfusion requirements in patients undergoing on-pump cardiac surgery. Systemic administration of lysine analogues, including tranexamic acid (TXA), has become the standard of care in patients undergoing on-pump coronary artery bypass graft (CABG) surgery to diminish perioperative blood loss and transfusion requirements. Here, we report the findings of a double-blind, randomized trial in low-risk CABG surgical patients that evaluated whether co-administration of intravenous and topical TXA has a significant impact on blood loss and transfusion requirements. Approval from our institutional ethics board was obtained, and written informed consent was given by each participant. Between December 1, 2011 and April 30, 2012 all patients scheduled for cardiac surgery at our institution were prospectively screened for trial participation. To limit participant heterogeneity, we recruited low-risk surgical candidates defined according to EUROScore criteria scheduled for elective or urgent CABG. Our primary outcome was the total volume of postoperative blood loss, determined by measuring mediastinal chest tube drainage. We calculated that a total sample size of 74 participants allowed 80% power to detect a 200 mL difference in total blood loss (type I error of 0.05) between groups. Secondary outcomes included chest tube losses at six and 12 hr, postoperative red blood cell transfusion requirement, and length of intensive care unit (ICU) stay. Adverse events of a thrombotic nature were recorded. Participants were randomized to receive an intraoperative topical TXA solution (study arm) or normal saline (control arm) prepared by our institutional clinical trials pharmacy according to a non-blocked randomization list generated before patient enrollment began. After general anesthesia, but prior to initiation of cardiopulmonary bypass, the study participants received a single intravenous bolus dose of TXA 30 mg kg over two minutes. Following removal of retractors and sponges prior to sternotomy closure, participants in the study arm received a cardiac bath of TXA solution containing 2 g TXA (1 g in 10 mL; Pfizer Canada, Saint-Laurent, QC, Canada) plus 50 mL of pre-warmed (42 C) normal saline. The control arm received 70 mL of pre-warmed normal saline only. This fluid remained within the pericardial cavity during placement of mediastinal chest tubes and chest closure. It was subsequently drained to the intraoperative cell-salvage machine by suction. The chest O. Prokopchuk-Gauk, MD Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, SK, Canada

Reply to Letter

for inflammation. However, and most importantly in terms of the scope and clinical significance of this study, there is absolutely no reference to patient outcome and inflammatory-mediated complications. The value of any clinical paper which focuses on the inflammatory response to CPB is considerably diminished if there is no clinical outcome element to it. The study of molecular responses to CPB are only that and, as in this case, simply confirm what we already know, that CPB is associated with the activation of an inflammatory response. What this means in terms of patient outcome is the most important aspect of such studies and it is only when these matters are taken into account that conclusions relating to the very important relative benefits of any new or pre-existing technologies can be drawn.