Unexplained in-hospital fever following cardiac surgery. Natural history, relationship to postpericardiotomy syndrome, and a prospective study of therapy with indomethacin versus placebo

Unveiling the nexus of postoperative fever and delirium in cardiac surgery: identifying predictors for enhanced patient care

Background

Postoperative delirium (POD) is a significant complication observed in cardiac surgery patients, characterized by acute cognitive decline, fluctuating mental status, consciousness impairment, and confusion. Despite its impact, POD often goes undiagnosed. Postoperative fever, a common occurrence after cardiac surgery, has not been comprehensively studied in relation to delirium. This study aims to identify perioperative period factors associated with POD in patients undergoing cardiopulmonary bypass, with the potential for implementing preventive interventions.

Methods

In a prospective observational study conducted between February 2023 and April 2023 at the Department of Cardio-Thoracic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, a total of 232 patients who underwent cardiac surgery were enrolled. POD assessment utilized the Confusion Assessment Method for the ICU (CAM-ICU), while high fever was defined as a bladder temperature exceeding 39°C. Statistical analysis included univariate and multivariate analyses, logistic regression, nomogram development, and internal validation.

Result

The overall incidence of postoperative delirium was found to be 12.1%. Multivariate analysis revealed that postoperative lactate levels [odds ratio (OR) = 1.787], maximum temperature (OR = 11.290), and cardiopulmonary bypass time (OR = 1.015) were independent predictors of POD. A predictive nomogram for POD was developed based on these three factors, demonstrating good discrimination and calibration. The prediction model exhibited a C-statistic value of 0.852 (95% CI, 0.763-0.941), demonstrating excellent discriminatory power. Sensitivity and specificity, based on the area under the receiver operating characteristic (AUROC) curve, were 91.2% and 67.9%, respectively.

Conclusion

This study underscores the high prevalence of POD in cardiac surgery patients and identifies postoperative lactate levels, cardiopulmonary bypass duration, and postoperative fever as independent predictors of delirium. The association between postoperative fever and POD warrants further investigation. These findings have implications for implementing preventive strategies in high-risk patients, aiming to mitigate postoperative complications and improve patient outcomes.

Postoperative Inflammation and Fever After Elective Aortic Valve and Aortic Root Replacement: A Retrospective Cohort Study

Background

Fever after cardiac surgery is common. More knowledge of postoperative fever could lead to better patient selection for diagnostic workup and empirical antibiotic treatment. We aimed to analyze the postoperative course of inflammation and fever after elective aortic valve and aortic root replacement.

Methods

In a retrospective single-center cohort study, we included 3 groups of patients after elective cardiac surgery: aortic root with aortic valve replacement (Bentall procedure, from 2014 to 2021), valve-sparing root replacement (VSRR, from 2014 to 2021), and isolated surgical aortic valve replacement (SAVR, from 2018 to 2021). Exclusion criteria were age <18 years, cardiac surgery other than described, use of deep-hypothermic circulatory arrest, reoperations, and preexisting infections. Primary outcome measure was the number of patients per group with postoperative fever (≥38°C). Secondary outcome measures were the percentage of patients per group with infections and outcome.

Results

Among 307 patients included (76 Bentall, 40 VSRR, 191 SAVR), 71% had postoperative fever. Fever occurred significantly more often in the Bentall (84%) and VSRR group (83%) compared with patients after SAVR (64%, P = .001). Seventeen patients had fever due to infection versus 202 with diagnoses of postoperative inflammation. In case of infection, fever was significantly higher (38.8°C vs 38.4°C, P = .03), and both the number of days with fever and hospital admission duration were significantly longer.

Conclusions

Postoperative fever is more often observed after Bentall procedure and VSRR compared to SAVR. In diagnoses of infection, there is a higher and prolonged fever.

Postoperative fever secondary to enoxaparin usage with pork allergy

Postoperative fevers are common in hospitalised patients and warrant workup beyond the early post-op period. A 50-year-old man was admitted after sustaining a tibial plateau fracture. Fevers began 3 days after external fixation and persisted through a second surgery despite initial negative workup. Careful review of medications revealed enoxaparin as the instigating agent of a febrile drug reaction, and the fevers resolved after discontinuing the drug. On further questioning, it was discovered the patient had an allergy to pork, from which the main components of enoxaparin are typically derived. To our knowledge, this is the first reported enoxaparin-induced fever in the setting of a pork allergy. Enoxaparin-induced fevers should be considered in patients with unexplained post-op fever. Our case demonstrates the importance of analysing newly administered medications. Simple detailed history may significantly reduce patient morbidity and help to broaden differentials during investigation.

Post-pericardiotomy syndrome: insights into neglected postoperative issues

ABSTRACT OBJECTIVES

Pericardial effusion is a common complication after cardiac surgery, both isolated and in post-pericardiotomy syndrome (PPS), a condition in which pleuropericardial damage triggers both a local and a systemic inflammatory/immune response. The goal of this review was to present a complete picture of PPS and pericardial complications after cardiac surgery, highlighting available evidence and gaps in knowledge.

METHODS

A literature review was performed that included relevant prospective and retrospective studies on the subject.

RESULTS

PPS occurs frequently and is associated with elevated morbidity and significantly increased hospital stays and costs. Nevertheless, PPS is often underestimated in clinical practice, and knowledge of its pathogenesis and epidemiology is limited. Several anti-inflammatory drugs have been investigated for treatment but with conflicting evidence. Colchicine demonstrated encouraging results for prevention.

CONCLUSIONS

Wider adoption of standardized diagnostic criteria to correctly define PPS and start early treatment is needed. Larger studies are necessary to better identify high-risk patients who might benefit from preventive strategies.

Placement of Labcor Pulmonary Conduit Results in a High Incidence of Postoperative Fever

BACKGROUND

Fever in the postoperative period in cardiac patients is common. The purpose of this study is to recognize the risk factors for prolonged postoperative fever in cardiac patients with pulmonary conduit insertion.

METHODS

Patients were identified retrospectively by looking at the International Classification of Diseases, Ninth Revision, Clinical Modification procedure code for pulmonary conduit insertion between June 2009 and December 2015 at the American University of Beirut Medical Center. Data about preoperative, perioperative, and postoperative variables were collected. Data entry and analysis were performed using SPSS version 22.

RESULTS

The study identified 59 patients. The most common type of pulmonary conduit used was the Contegra type (57.6%) (n = 34), followed by the Labcor type (20.3%; n = 12). Postoperative fever occurred in 61% of patients (n = 36). Fourteen patients (38.8%) had a prolonged fever that lasted for more than seven days. Prolonged postoperative fever was significantly associated with the Labcor pulmonary conduit (P value < .001) and a longer duration of pacing wires (P value: .039). Significantly prolonged fever that lasted for more than 21 days occurred in five patients who all had inserted the Labcor pulmonary conduit.

CONCLUSIONS

The Labcor pulmonary conduit type is a risk factor for prolonged postoperative fever. The protracted use of pacing wires could be a consequence of the prolonged fever rather than a cause. In the absence of a demonstrable infectious etiology for prolonged postoperative fever in cardiac patients with pulmonary conduit insertion, the Labcor pulmonary conduit could be the underlying cause. Alternative management of such cases may lead to decreased antibiotic use and morbidity.

Post-operative fever (POF) after cardiac surgery in a low- and middle-income-country: 7-year institutional experience

BACKGROUND

Post-operative fever (POF) after cardiac surgery in a developing country is of great concern because of the associated morbidity and mortality. In our country, we experience this complication more because of a high rate of malaria infestations, gastroenteritis, and malnutrition. We also experience a low yield of positive diagnostic tests when POF develops; this is partly due to expense and the prioritisation of other essential items in our poorly equipped cardiac ICU.

AIMS/OBJECTIVE

To assess the causes of POF after cardiac surgery and determine its impact on the outcome on patients.

MATERIALS AND METHODS

International Cardiac Surgery Mission teams visited our centre for 7 years (2013-2019). During this period, a significant number of cardiac surgeries were performed. A retrospective study of patients with POF was performed with data from our hospital's database, and included standard demographics; types of surgery performed, and management protocols being used in the peri-operative care.

RESULTS

A total of 242 patients were treated during the study period and underwent 266 surgeries. Of these, 151 (56.8%) and 115 (43.2%) were adult and paediatric cases respectively. Ages ranged between 0 and 90 years; 34 (14.1%) had POF. When we evaluated the clinical and associated laboratory findings, pyrexia (temp >38.0 °C) and elevated white blood cell count with differential neutrophilia were present in 10 patients (29.4%). The time of onset and duration of POF were between <24 and >144 hours. In the invasive procedure related to POF, sternotomy infections were present in seven patients (18.4%). Malaria infestations and breach in sterility protocol were predominant.

CONCLUSION

The management of POF in the cardiac ICU was complicated by the requirement of co-operation from a larger number of specialties than is usually required in advanced centres with special expertise in malaria confirmation. We, therefore, introduced structured clinical, laboratory, and appropriate interventions to treat POF more aggressively. We found that more careful attention to peri-operative details to ensure strict observation of sterility protocol with anti-malaria prophylaxis led to improvements in our centre's outcomes.

Postpericardiotomy syndrome after cardiac surgery

Postpericardiotomy syndrome (PPS) is a well-known complication after cardiac surgery. The syndrome results in prolonged hospital stay, readmissions, and invasive interventions. Previous studies have reported inconsistent results concerning the incidence and risk factors for PPS due to the differences in the applied diagnostic criteria, study designs, patient populations, and procedure types. In recent prospective studies the reported incidences have been between 21 and 29% in adult cardiac surgery patients. However, it has been stated that most of the included diagnoses in the aforementioned studies would be clinically irrelevant. This challenges the specificity and usability of the currently recommended diagnostic criteria for PPS. Moreover, recent evidence suggests that PPS requiring invasive intervention such as the evacuation of pleural and/or pericardial effusion is associated with increased mortality. In the present review, we summarise the existing literature concerning the incidence, clinical features, diagnostic criteria, risk factors, management, and prognosis of PPS. We also propose novel approaches regarding to the definition and diagnosis of PPS. Key messages: Current diagnostic criteria of PPS should be reconsidered, and the analyses should be divided into subgroups according to the severity of the syndrome to achieve more clinically applicable and meaningful results in the future studies. In contrast with the previous presumption, severe PPS - defined as PPS requiring invasive interventions - was recently found to be associated with higher all-cause mortality during the first two years after cardiac surgery. The association with an increased mortality supports the use of relatively aggressive prophylactic methods to prevent PPS. The risk factors clearly increasing the occurrence of PPS are younger age, pleural incision, and valve and ascending aortic procedures when compared to CABG.

Postoperative Non-Pathological Fever Following Posterior Cervical Fusion Surgery : Is Laminoplasty a Better Preventive Method than Laminectomy?

Objective

To analyze the incidence and characteristics of delayed postoperative fever in posterior cervical fusion using cervical pedicle screws (CPS).

Methods

This study analyzed 119 patients who underwent posterior cervical fusion surgery using CPS. Delayed fever was defined as no fever for the first 3 postoperative days, followed by an ear temperature ≥38℃ on postoperative day 4 and subsequent days. Patient age, sex, diagnosis, laminectomy, surgical level, revision status, body mass index, underlying medical disease, surgical duration, and transfusion status were retrospectively reviewed.

Results

Of 119 patients, seven were excluded due to surgical site infection, spondylitis, pneumonia, or surgical level that included the thoracic spine. Of the 112 included patients, 28 (25%) were febrile and 84 (75%) were afebrile. Multivariate logistic regression analysis showed that laminectomy was a statistically significant risk factor for postoperative non-pathological fever (odds ratio, 10.251; p=0.000). In contrast, trauma or tumor surgery and underlying medical disease were not significant risk factors for fever.

Conclusion

Patients who develop delayed fever 4 days after posterior cervical fusion surgery using CPS are more likely to have non-pathologic fever than surgical site infection. Laminectomy is a significant risk factor for non-pathologic fever.

Controversies in the prophylaxis and treatment of postsurgical pericardial syndromes: a critical review with a special emphasis on paediatric age

Postsurgical pericardial syndromes are common complications after cardiac surgery; however, their treatment is not well established yet. We reviewed the accuracy and limits of clinical trials of prophylaxis and treatment of these diseases to identify an evidence-based therapeutic approach. We performed a literature search in the National Library of Medicine using the keywords pericardial effusion, cardiac surgery and paediatric/congenital. The research was then redefined adding separately the keywords postpericardiotomy syndrome, NSAIDs, steroids and colchicine. We found 12 clinical trials (eight for the prophylaxis and four regarding treatment), testing three major agent classes: NSAIDs, corticosteroids and colchicine. Therapy is generally based on NSAID with or without steroids with the adjunct of colchicine for recurrences. Only a few randomized controlled trials (RCTs) in adults support NSAID therapy. Efficacy of steroids has been proved only in small paediatric works, whereas no studies are available for colchicine. Studies furthermore presented some limitations: not univocal endpoints (not allowing for a meta-analysis), a limited sample size, scarce attention to confounders (such as the underlying cardiac disease and diuretic/analgesic regimen). Moreover, different agents were not assessed, nor when to start therapy. More evidence (two wide RCT plus a meta-analysis) supports the role of colchicine for prophylaxis in adults. Prophylaxis with NSAID/corticosteroids instead failed to have significant advantage in children, whereas a few data are available for adults. Evidence for the treatment of postsurgical pericardial syndromes is incomplete, making it difficult to understand when to treat and which agent to employ, especially in children.

Evaluation of fever and infections in cardiac surgery patients

Fever following cardiac surgery is common and may be infectious or noninfectious in etiology. In this article, we review the major causes of postoperative fever while highlighting special considerations in cardiac surgery patients. We also outline a structured approach to evaluation and present an overview of diagnostic and management considerations for mediastinitis, postpericardiotomy syndrome, prosthetic valve endocarditis, aortic vascular graft infections, and ventricular assist device infections.

Advantages of 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography in detecting post cardiac surgery infections

The 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) offers an excellent negative predictive value. Consequently, it is a reliable tool for excluding an infectious phenomenon in case of negativity. In case of persistent fever of unknown origin after cardiac surgery and in combination with other bacteriological examinations and medical imaging, we can rely on FDG-PET/CT to confirm or eliminate deep infections and prosthetic endocarditis. For this reason, FDG-PET/CT should be considered among the examinations to be performed in case of suspected infection after cardiac surgery. We have reported the case of a 76-year-old man who presented with a fever of unknown origin and recurrent septic shocks after a biological Bentall procedure combined with left anterior descending (LAD) coronary artery revascularization by the left internal thoracic artery. We performed a FDG-PET/CT which showed external iliac vein and right common femoral vein hyperfixation with infiltration of adjacent soft tissues, highly suspected to be an infectious process.

LEARNING OBJECTIVE

The aim of this case report is to show that FDG-PET/CT, in combination with other bacteriological examinations and medical imaging, can be extremely helpful in detecting deep infectious sources, even during the early postoperative period.

The efficacy of parecoxib on systemic inflammatory response associated with cardiopulmonary bypass during cardiac surgery

AIMS

Cardiopulmonary bypass (CPB) during cardiac surgery is well known to be associated with the development of a systemic inflammatory response. The efficacy of parecoxib in attenuating this systemic inflammatory response is still unknown.

METHODS

Patients undergoing elective mitral valve replacement with CPB were assessed, enrolled and randomly allocated to receive parecoxib (80 mg) or placebo. Blood samples were collected in EDTA vials for measuring serum cytokine concentrations, troponin T, creatinekinase myocardial-brain isoenzyme CK-MB concentrations and white cell counts.

RESULTS

Compared with the control group, IL-6 and IL-8-values in the parecoxib group increased to a lesser extent, peaking at 2 h after the end of CPB (IL-6 31.8 pg ml⁻¹ ± 4.7 vs. 77.0 pg ml⁻¹ ± 14.1, 95% CI -47.6, -42.8, P < 0.001; IL-8 53.6 pg ml⁻¹ ± 12.6 vs. 105.7 pg ml⁻¹ ± 10.8, 95% CI -54.8, -49.4, P < 0.001). Peak concentrations of anti-inflammatory cytokine IL-10 occurred immediately after termination of CPB and were higher in the parecoxib group (115.7 pg ml⁻¹ ± 10.5 vs. 88.4 pg ml⁻¹ ± 12.3, 95% CI 24.7, 29.9, P < 0.001). Furthermore, the increase in neutrophil counts caused by CPB during cardiac surgery was inhibited by parecoxib. The increases in serum troponin T and CK-MB concentrations were also significantly attenuated by parecoxib in the early post-operative days. Peak serum concentrations of CK-MB in both groups occurred at 24 h post-CPB (17.4 μg l⁻¹ ± 5.2 vs. 26.9 μg l⁻¹ ± 6.9, 95% CI -10.9, -8.1, P < 0.001). Peak troponin T concentrations occurred at 6 h post-bypass (2 μg l⁻¹ ± 0.62 vs. 3.5 μg l⁻¹ ± 0.78, 95% CI -1.7, -1.3, P < 0.001).

CONCLUSION

Intra-operative parecoxib attenuated the systemic inflammatory response associated with CPB during cardiac surgery and lowered the biochemical markers of myocardial injury.

Approach to postoperative fever in pediatric cardiac patients

Fever in the postoperative period in children undergoing surgery for congenital heart disease is fairly common and tends to cause anxiety to both the surgeon and the patient. Such fever is associated with the metabolic response to trauma, systemic response to the cardiopulmonary bypass, hypothermia, presence of drainage tubes, drugs, blood transfusion as well as infections. Establishing the diagnosis requires proper assessment of the patient with focused history, targeted physical examination and judicious use of investigations with the knowledge of the common causes.

Noninfectious fever following aortic surgery: incidence, risk factors, and outcomes

OBJECTIVE

To determine the incidence, course, potential risk factors, and outcomes of noninfectious fever developed in patients after aortic surgery.

METHODS

patients who received operation for aortic aneurysm or dissection in our center from January 2006 to January 2008 were reviewed. Patients who met one of the following criteria were excluded: having a known source of infection during hospitalization; having a preoperative oral temperature greater than or equal to 38.0 degrees C; undertaking emergency surgery; having incomplete data. Univariate analysis was performed in patients with noninfectious postoperative fever and those without, with respect to demographics, intraoperative data, etc. Risk factors for postoperative fever were considered for the multivariate logistic regression model if they had a P value less than 0.10 in the univariate analysis.

RESULTS

Totally 463 patients undergoing aortic surgery were enrolled for full review. Among them, 345 (74.5%) patients had noninfectious postoperative fever, the other 118 (25.5%) patients didn't develop postoperative fever. Univariate analysis demonstrated that several risk factors were associated with the development of noninfectious postoperative fever, including weight, surgical procedure, minimum intraoperative bladder temperature, temperature upon intensive care unit (ICU) admission, discharge, and during ICU stay, as well as blood transfusion. In a further multivariate analysis, surgical site of thoracic and thoracoabdominal aorta (odds ratio: 4.861; 95% confidence interval: 3.029-5.801; P=0.004), lower minimum intraoperative bladder temperature (odds ratio: 1.117; 95% confidence interval: 1.01-1.24; P=0.04), and higher temperature on admission to the ICU (odds ratio: 2.57; 95% confidence interval: 1.28-5.18; P=0.008) were found to be significant predictors for noninfectious postoperative fever. No difference was found between the febrile and afebrile patients with regard to postoperative hospitalization duration (P=0.558) or total medical costs (P=0.896).

CONCLUSION

Noninfectious postoperative fever following aortic surgery is very common and closely related with perioperative interventions.

The effect of short-term prophylactic acetylsalicylic acid on the incidence of postpericardiotomy syndrome after surgical closure of atrial septal defects

Postpericardiotomy syndrome (PPS), a potential complication of open heart surgery, has a variable clinical course and severity. This study evaluated the effectiveness of acetylsalicylic acid (ASA) prophylaxis in preventing PPS after surgical closure of atrial septal defects (ASDs) in pediatric patients. A retrospective review was performed for 177 patients who underwent uncomplicated ASD closure from 1986 to 2006. The study group received prophylactic ASA 20 to 50 mg/kg/day for 1 to 6 weeks after surgery, whereas the control group did not. The primary outcome was a diagnosis of PPS based on the presence of two or more of the following symptoms or signs occurring at least 72 h postoperatively: fever (temperature >38 degrees C), pericardial or pleural rub, and worsening or recurring anterior pleuritic chest pain. Consequently, PPS developed in 5 (2.8%) of the 177 children: 2.8% (3/106) in the control group and 2.8% (2/71) in the study group (p = 1.00). The secondary outcomes were frequency of other postoperative complications. Postoperative pericardial effusions experienced by 26.7% of the patients were identified more frequently in the treatment group (p < 0.001). Postoperative prophylaxis ASA at a dose of 20 to 50 mg/kg/day for 1 to 6 weeks after surgical closure of ASD does not decrease the incidence of PPS in pediatric patients.

Risk Factors of Prosthetic Valve Endocarditis: A Case-Control Study

BACKGROUND

Prosthetic valve endocarditis is an important cause of the morbidity and mortality associated with heart valve replacement surgery. The objective of this study was to assess risk factors of prosthetic valve endocarditis related to patients, perioperative events, and postoperative complications.

METHODS

This was a retrospective case-control study conducted in a tertiary care hospital in Santander, Spain, from January 1986 to January 1998. Cases were patients with "definite" and "possible" infective endocarditis defined according to the Durack criteria. Controls were patients undergoing prosthetic valve replacement who at the time of the study had not developed infective endocarditis. Information was abstracted from medical records. Cases and controls (1:2) were matched by sex, age at operation (+/- 5 years), surgery of one or more valves in the same anatomic position, and date of operation (+/- 6 months).

RESULTS

There were 81 cases and 162 controls. In the multivariate analysis, risk factors significantly associated with prosthetic valve endocarditis were functional class III or IV (New York Heart Association), alcohol consumption, prior history of endocarditis, fever in the intensive care unit, and gastrointestinal bleeding. Functional class III or IV and complications of the surgical wound were independent predictors of early infective endocarditis, whereas fever in the intensive care unit and gastrointestinal bleeding were predictors of prosthetic valve endocarditis late after operation.

CONCLUSIONS

Patients with prosthetic valve endocarditis differ from people without infective endocarditis with regard to intrinsic and postoperative risk factors but not regarding perioperative-related variables.

Modulation of systemic inflammatory response after cardiac surgery

Cardiac surgery and cardiopulmonary bypass initiate a systemic inflammatory response largely determined by blood contact with foreign surfaces and the activation of complement. It is generally accepted that cardiopulmonary bypass initiates a whole-body inflammatory reaction. The magnitude of this inflammatory reaction varies, but the persistence of any degree of inflammation may be considered potentially harmful to the cardiac patient. The development of strategies to control the inflammatory response following cardiac surgery is currently the focus of considerable research efforts. Diverse techniques including maintenance of hemodynamic stability, minimization of exposure to cardiopulmonary bypass circuitry, and pharmacologic and immunomodulatory agents have been examined in clinical studies. This article briefly reviews the current concepts of the systemic inflammatory response following cardiac surgery, and the various therapeutic strategies being used to modulate this response.

[Frequency of postoperative fever in children with congenital heart disease undergoing cardiovascular surgery and associated risk factors]

OBJECTIVES

To determine the frequency of postoperative fever in children with congenital heart disease who undergo cardiovascular surgery, and the risk factors associated.

PATIENTS AND METHODS

In a prospective cohort study, 100 children under the age of less than 9 years were followed-up during hospitalization in order to detect fever after cardiac surgery. Preoperative, perioperative, and postoperative variables were assessed to determine their relationship with postoperative fever. The cases were patients who developed fever. Multivariate analysis was used, and the odds ratio (OR) and 95% confidence intervals (95% CI) were calculated.

RESULTS

The frequency of postoperative fever was 46%. Fever appeared within 24 hours of surgery in 56% cases. In 32/46 (70%) cases, fever remitted within 72 hours. Fever was more common in patients who underwent open-heart surgery than in those treated with a closed technique (28 vs. 18, P = 0.045). Prolonged extracorporeal circulation (OR = 1.024; 95% CI, 1.004-1.045), aortic cross-clamping (OR = 2.83; 95% CI, 1.21-6.61) and postoperative infections (OR = 24.07; 95% CI, 7.2-75.0) were the risk factors associated with the development of postoperative fever.

CONCLUSIONS

Postoperative fever is common in children with congenital heart disease. The identification of risk factors associated to the development of fever should help clinicians to identify the cause of fever in this group of patients.

Increased plasma concentrations of serum amyloid A: an indicator of the acute-phase response after cardiopulmonary bypass

OBJECTIVES

To assess the expression of mixed and hepatic venous serum amyloid A (SAA) concentrations and its relationship to plasma concentrations of C-reactive protein, interleukin-6 (IL-6), and endotoxin during and after cardiopulmonary bypass (CPB).

DESIGN

Prospective, consecutive sample with repeated measurements.

SETTING

Surgical intensive care unit (ICU) in a university hospital.

PATIENTS

Twenty patients who underwent elective coronary bypass grafting.

INTERVENTIONS

A radial artery catheter, pulmonary artery catheter, and right hepatic vein catheter were inserted. Blood samples were collected to determine the different mediators, lactate concentrations, and oxygen saturations.

MEASUREMENTS AND MAIN RESULTS

After induction of anesthesia, baseline values were obtained and the following parameters were determined 20 mins after onset of CPB, 20 mins after termination of CPB, at admission to the ICU, and 6, 8, 12, and 24 hrs later: hemodynamics, body core temperature, hepatic venous oxygen saturation, and mixed and hepatic venous lactate, endotoxin, interleukin (IL)-6, C-reactive protein (CRP), and SAA concentrations. Endotoxin and IL-6 plasma concentrations increased during CPB, peaked 6 hrs after admission to the ICU (endotoxin: 23.1 +/- 6.2 pg/mL; IL-6: 646 +/- 104 pg/mL), and decreased thereafter; SAA and CRP concentrations began to increase after 6 and 8 hrs, respectively, with the highest concentrations reached 24 hrs postoperatively (CRP: 14 +/- 3.6 mg/L; SAA: 668 +/- 114 micrograms/mL). Lactate concentrations began to increase 20 mins after CPB, and continued to increase until 12 hrs postoperatively. There were no significant differences between mixed and hepatic venous values of endotoxin, IL-6, CRP, SAA, and lactate (p < .05). Body core temperature, which was < 37.5 degrees C before surgery for all patients, increased 6 hrs after admission to the ICU and peaked 12 hrs postoperatively (38.3 +/- 1.1 degrees C). Hepatic venous oxygen saturation did not change. Correlations were obtained between IL-6 values and heart rate (r2 = .20; p < .005), and endotoxin concentrations and systemic vascular resistance (r2 = .18; p < .001). Body core temperature correlated significantly closer with SAA (r2 = .52; p < .0001) values than with IL-6 (r2 = .27; p < .0001) or CRP (r2 = .16; p < .001) values (p < .05).

CONCLUSIONS

SAA is an additional and sensitive marker of the acute-phase response following CPB; the increase in SAA concentrations parallels the temporary increase in body core temperature and is preceded by endotoxemia and IL-6 secretion.

Different activation patterns in the plasma kallikrein-kinin and complement systems during coronary bypass surgery

Components of the plasma kallikrein-kinin and complement systems were determined in patients undergoing open heart surgery with cardiopulmonary bypass. Spontaneous kallikrein activity (KK), plasma prekallikrein (PKK), functional kallikrein inhibition capacity (KKI), C3 activation products (C3-act), and the terminal complement complex (TCC) were measured. A marked, transitory increase in KK and a decrease in PKK were found prior to cardiopulmonary bypass just after heparin injection. An additional decline in PKK and KKI during bypass with a return to near control levels in the postoperative period was observed. C3-act increased in all patients during bypass, reaching a peak value at wound closure. The TCC concentration also increased significantly during cardiopulmonary bypass, returned to control levels in the early postoperative period, and then increased again in the late postoperative period. It is concluded that activation of the kallikrein-kinin system started after injection of heparin, prior to cardiopulmonary bypass. Activation of both the initial and the terminal complement cascade, however, started only after onset of cardiopulmonary bypass.

Postpericardiotomy syndrome

Postpericardiotomy syndrome, a frequent complication of open-heart surgery, is characterized by fever, chest pain, and pericardial and pleural effusions. These signs may develop 1 to 12 weeks after intracardiac surgery in approximately 30 percent of patients. Although the etiology of the syndrome is unknown, evidence points to a viral and/or autoimmune cause. Postpericardiotomy syndrome is diagnosed after excluding other conditions such as endocarditis and pneumonia. In many cases, the syndrome is self-limiting and occurs only once, but in other cases the symptoms have recurred as many as eight times. When the symptoms recur, management is more difficult because optimal pharmacologic treatment is not known. Antiinflammatory agents, such as salicylates and steroids, represent the drugs most commonly used. Although analgesics with codeine or oxycodone are important for the patients' symptomatic relief, early recognition of the syndrome is the key to limiting the discomfort and possible complications associated with this condition.

Clinical features and long-term natural history of the postpericardiotomy syndrome

We followed 34 consecutive patients with the postpericardiotomy syndrome for a median of 7 years. In each patient, the syndrome was documented by the occurrence of: (1) a pericardial type of pain or pericardial rub (or both); and (2) fever or an elevated erythrocyte sedimentation rate. The postpericardiotomy syndrome occurred at a median postoperative time of 4 weeks (range, 2 to 52 weeks). The duration of the syndrome was highly variable (range, 2 to 100 days; median, 22 days) and depended primarily on treatment; the median duration of symptoms in 21 patients treated with salicylates alone was only 4 days. Of the 9 patients receiving anticoagulants alone and in whom this treatment was continued, none had clinical evidence of hemopericardium. On follow-up, 7 patients (21%) had an initial recurrence at an interval of 1 to 3 months; 5 of these patients had further recurrences at an interval of 3 to 30 months. This long-term study indicates that the postperiocardiotomy syndrome is a benign but often recurrent clinical entity, presumably related to viral and/or immunologic factors.

Fever and infection after cardiac operation

The occurrence of fever (daily maximal temperature greater than or equal to 38 degrees C) was analyzed in 123 patients after open-heart operation. A statistical difference was found in the incidence of fever after the third postoperative day between patients without infection and patients with bacteremia, wound infection, or pneumonia. Fever after the third day should prompt a diligent search for deep-seated infection.

Changes in body temperature after administration of antipyretics, LSD, delta 9-THC, CNS depressants and stimulants, hormones, inorganic ions, gases, 2,4-DNP and miscellaneous agents

This survey concludes a series of complications of data from the literature, primarily published since 1965, on thermoregulatory effects of antipyretics in afebrile as well as in febrile subjects, LSD and other hallucinogens, cannabinoids, general CNS depressants, CNS stimulants including xanthines, hormones, inorganic ions, gases and fumes, 2,4-dinitrophenol and miscellaneous agents including capsaicin, cardiac glycosides, chemotherapeutic agents, cinchona alkaloids, cyclic nucleotides, cycloheximide, 2-deoxy-D-glucose, dimethylsulfoxide, insecticides, local anesthetics, poly I:poly C, spermidine and spermine, sugars, toxins and transport inhibitors. The information listed includes the species used, route of administration and dose of drug, the environmental temperature at which the experiments were performed, the number of tests, the direction and magnitude of body temperature change and remarks on the presence of special conditions such as age or lesions, or on the influence of other drugs, such as antagonists, on the response to the primary agents.