key: cord-0824462-hc6a1vwj
authors: Barkhordari, Khosro; Khajavi, Mohamad R.; Bagheri, Jamshid; Nikkhah, Sepideh; Shirzad, Mahmood; Barkhordari, Sepehr; Kharazmian, Katayun; Nosrati, Marjan
title: Early respiratory outcomes following cardiac surgery in patients with COVID‐19
date: 2020-08-13
journal: J Card Surg
DOI: 10.1111/jocs.14915
sha: 9a7434768cd5da73b2169c88cf372b2876cb4c27
doc_id: 824462
cord_uid: hc6a1vwj

BACKGROUND: Both coronavirus disease (COVID‐19) and cardiac surgery have a negative impact on pulmonary function. This study aimed to determine the postoperative respiratory outcomes of patients with COVID‐19 who underwent cardiac surgery. METHODS: In this retrospective study, we reviewed and analyzed the patient characteristics and clinical data of 25 asymptomatic patients with COVID‐19 who underwent urgent or emergency cardiac surgery at Tehran Heart Center Hospital, Iran, between 29 February and 10 April 2020. RESULTS: The mean age, EuroSCORE, and body mass index were 57.3 ± 15.1 years, 6.65 ± 1.29, and 25.7 ± 3.7 kg/m(2), respectively. Four patients underwent off‐pump cardiac surgery and 21 underwent on‐pump cardiac surgery with a median cardiopulmonary bypass time of 85 minutes (interquartile range (IQR, 50‐147). The overall mortality rate and the length of stay in the intensive care unit (ICU) were higher compared to those of a propensity‐matched group of patients who underwent cardiac surgery in the pre‐COVID era. The median intubation time was 13 hours (IQR, 9.5‐18), which was comparable to that of pre‐COVID cardiac surgery patients. The readmission rate to the ICU was 16%. In this ICU readmitted group, the mean oxygen index, FiO(2), and mortality rate were higher and the PaO(2)/FiO(2) ratio was lower than those of the nonreadmitted patients. CONCLUSIONS: Although early respiratory outcomes of asymptomatic COVID‐19 patients who underwent early cardiac surgery appeared to be satisfactory, compared to the propensity‐scored matched non‐COVID group, the postoperative outcomes were worse, especially in the ICU readmitted patients. We suggest postponing cardiac operations unless the patient requires emergency surgery.

On 11 March 2020, the World Health Organization (WHO) declared the coronavirus disease (COVID-19) as a pandemic. Unfortunately, Iran was one of the worst affected countries. COVID-19 mainly affects the lungs. Approximately 80% of symptomatic patients with COVID-19 develop the mild disease, while 15% develop severe disease with hypoxemia, dyspnea, and tachypnea, and 5% become critically ill with respiratory failure, septic shock and/or multiorgan dysfunction. 1 Abnormalities are visible on chest computed tomography (CT) in 85% of patients. 2 The majority of patients with the severe respiratory disease require invasive mechanical ventilation. 3 Inflammatory renal and lung diseases, such as acute respiratory distress syndrome (ARDS) and acute renal failure are serious complications of both COVID-19 and cardiopulmonary bypass (CPB). 3, 4 There are few studies regarding the clinical outcomes of patients with COVID-19 in the intensive care unit (ICU). ICU mortality is between 22% and 66% in nonsurgical patients. 3, 5 In a recent large case series in Italy, the mortality rate of patients admitted to ICU was about 26%. 3 There is little information available about the clinical outcomes of surgical COVID-19 patients. The surgery itself and mechanical ventilation have negative impacts on the lung. CPB aggravates these injuries even further in cardiac surgery patients. 6 In a retrospective cohort study of general surgical COVID-19 patients, all had lung CT abnormalities after surgery, and the mortality rate in ICU was 20.5%. 7 Studies about airway management during surgery in patients with COVID-19 are rare, and we based our strategies on the recommendations and suggestions of experts. 8 Experts recommend a lung protection strategy for intubated COVID-19 patients, similar to that in other ARDS patients 9,10 ; we tried to apply these recommendations in the best possible way in the management of our patients. We were unable to find any study that focused on the postanesthesia respiratory outcomes of cardiac surgery patients. Our study aimed to explore the early postoperative respiratory outcomes of asymptomatic patients with COVID-19 who underwent urgent or emergency surgery at the discretion of the cardiac surgeons and cardiologists of our hospital. We hope that this study will provide useful information on the postoperative respiratory course of patients with COVID-19 who undergo cardiac surgery.

In this retrospective study, the baseline characteristics and clinical data of patients with COVID-19 who underwent urgent or emergency cardiac surgery at Tehran Heart Center Hospital, Iran, between 29 February and 10 April 2020, and fulfilled our study criteria were reviewed and analyzed. Informed consent was obtained from all patients regarding using their medical information for research purposes. This study was approved by the research committee of the Tehran Heart Center for medical record review. The COVID-19 diagnosis was confirmed by a team comprising of a radiologist, an infectious disease specialist, and an intensivist, based on positive reverse transcription-polymerase chain reaction (RT-PCR) tests and/or chest CT according to the WHO interim guidance. 10 All of the patients were asymptomatic from their time of admission to the operating room and were receiving hydroxychloroquine and azithromycin. In addition, some were also prescribed antiviral drugs.

General anesthesia was induced with routine anesthetic drugs. Onpump cardiac surgery was done in 21 (84%) patients, while four patients (16%) had off-pump surgery. The types of operations were diverse, and the majority of the patients had a coronary artery bypass graft (CABG) or combined CABG-valve surgeries with a mean graft number of 2.17 ( Table 1) 

The patient characteristics and other relevant data were collected from the medical records. Furthermore, the ICU flow sheets and the data of the pre-COVID-19 cardiac surgery patients were retrieved from our surgery database. Data of patients that were 18-years old or younger had active respiratory disease, renal and hepatic failure, or a history of uncontrolled respiratory diseases were excluded. Hemodynamic and respiratory parameters, average fluid balance over 3 days, serum creatinine, postoperative bleeding, reopening of the chest due to surgical complications, amount of received packed red blood cells, and blood components were collated from the ICU flow sheets.

EuroSCORE II was used for the risk stratification of the patients. 11 

Our primary respiratory outcomes were extubation failure rate, intubation time, PaO 2 /FiO 2 ratio, oxygen index, and the mean airway pressure (MAWP). Other outcomes included length of stay in ICU (ICU LOS), rate of readmission to ICU, acute kidney injury (AKI), and mortality within 30 days of surgery. The PaO 2 /FiO 2 ratio and oxygenation index calculated from the computation of PaO 2 , FiO 2 , and MAWP variables were based on their specific formula. The severity of ARDS was determined using the PaO 2 /FiO 2 ratios based on the Berlin definition. 12 AKI was defined based on changes in serum creatinine according to the KDIGO guidelines for postoperative patients. 13 

Continuous variables are presented as the mean ± SD (standard deviation) or median (interquartile range; IQR). Categorical variables are expressed as frequencies and percentages. Quantitative variables were compared using the Student t test or the Mann-Whitney U test, as appropriate, while categorical variables were compared using the χ 2 or the Fisher exact test as required. The statistical analysis was performed with SPSS software, version 21 (SPSS Inc. Chicago, IL) and SAS version 9.2 (SAS Institute, Inc). All P values were two-tailed and a P ≤ .05 was considered to be statistically significant.

A total of 25 patients who had COVID-19 and underwent cardiac surgery were enrolled in the study. Twenty-one patients had positive RT-PCR tests, and four had positive chest CT showing pneumonia.

The baseline characteristics of patients are shown in Table 1 . The mean age was 57.3 ± 15 years, and the mean EuroSCORE was 6.56 ± 1.29. The median body mass index was 26.3 kg/m 2 (IQR, 22.5-28.6). Sixty-eight percent of the patients had one or more comorbidities. Hypertension (56%) was the most common, followed by diabetes type 2 (40%). Twenty percent of the patients were cigarette smokers. There was no statistical difference between the patients that were readmitted to ICU and those that were not in terms of the baseline characteristics. Compared to the nonadmitted group, the FiO 2 , oxygen index, and PEEP were higher, and the PaO 2 /FiO 2 ratio was lower ( In that study, the rate of ICU admission was 44%. Patients in that study underwent elective surgeries, whereas our patients had an emergency or urgent surgeries. In addition, the number of patients with at least one morbidity was higher in the current study. Hypertension was the most common comorbidity in our cohort, which is consistent with other studies. 3, 7 The median EuroSCORE of our patients was 7.50 (IQR, 6.5-8.5), indicating that the risk of morbidity and mortality was high. The overall mortality of our patients was 16%, which is higher than the non-COVID-19 cardiac surgery patients (P = .040).

Hemodynamic complications, as well as cardiogenic and septic shocks, are not uncommon in patients with COVID-19. 7, 14 In a study by Lei, 53% of the patients admitted to the ICU had shock, and 33% had cardiac arrhythmias. As inotropes are usually used to support hemodynamics in cardiac surgery patients, it is difficult to compare the incidence rate of Emergency or urgent surgery, old age, comorbidities, and high frailty scores are associated with a longer mechanical ventilation time in cardiac surgery patients. 18 The initial intubation time in the present study was not different from our non-COVID-19 cardiac surgery patients ( Table 3 ), indicating that the early respiratory course was unremarkable. We had only one case of extubation failure in the ICU.

This patient was reintubated in 8 hours, extubated 2 days later, and discharged from ICU but was then readmitted after 5 days. In addition, we could not wean and extubate another one of our patients and he died during the first 7 days of his stay in ICU. Unlike the postsurgery patients in the study by Lei et al, 7 in which fever was the most common symptom, in the present study, low SpO 2 (<87%) was the most common first sign (80%). Fever (72%), respiratory distress (64%), headache (28%), and cough (28%) were also common signs and symptoms. The majority of the patients improved with routine supportive care. However, four patients were readmitted to the ICU due to respiratory and hemodynamic problems. The respiratory and ventilator indices in the readmitted group were unfavorable during their second ICU stay (Table 2) . Three (75%) of these patients suffered from severe ARDS and one had moderate ARDS. The mean PEEP and mean airway pressure values were higher than the nonreadmitted group (P = .01).

The median ICU LOS in the readmitted group was 6.5 (IQR, 5.25-23.23), which was longer than that of the nonreadmitted group.

Three (75%) of these patients died, which, by comparison with our nonreadmitted group and the nonsurgical ICU admitted patients in the study by Grasselli et al, 3 is high. This indicates that symptomatic postcardiac surgery patients have a very high risk of mortality.

This study has several limitations. First, this study is a retrospective study, and the data was collected from the medical records and flow sheets. As such, some of the data was missing. Second, the sample size was too small to make an accurate comparison between the groups. Third, patients in post ICU and other wards were not monitored to the same extent as those in the cardiothoracic ICU.

Fourth, at the peak of the COVID-19 pandemic, we did not always have enough test kids to test our patients.

Even though the respiratory outcomes of asymptomatic COVID-19

patients that underwent early postcardiac surgery appeared to be satisfactory, the rate of readmission to the ICU was high. The patients that were readmitted to ICU had high rates of severe ARDS and mortality. Therefore, we suggest postponing cardiac operations on patients with COVID-19 unless they require emergency surgery.

Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: summary of a report of 72 314 cases from the Chinese Center for Disease Control and Prevention

Clinical characteristics of coronavirus disease 2019 in China

Baseline characteristics and outcomes of 1591 patients infected with SARS-CoV-2 admitted to ICUs of the Lombardy region

Incidence and risk factors of pulmonary complications after cardiopulmonary bypass

Care for critically ill patients with COVID-19

Cardiopulmonary bypass time is an independent risk factor for acute kidney injury in emergent thoracic aortic surgery: a retrospective cohort study

Clinical characteristics and outcomes of patients undergoing surgeries during the incubation period of COVID-19 infection

Respiratory support for patients with COVID-19 infection

Surviving sepsis campaign: guidelines on the management of critically ill adults with coronavirus disease 2019 (COVID-19)

Clinical management of severe acute respiratory infection when novel coronavirus (2019-nCoV) infection is suspected: interim guidance

Comparison of EuroSCORE II, original EuroSCORE, and the society of thoracic surgeons risk score in cardiac surgery patients

Acute respiratory distress syndrome

Diagnosis, evaluation, and management of acute kidney injury: a KDIGO summary (Part 1)

The variety of cardiovascular presentations of COVID-19

Emergency coronary artery bypass grafting: indications and outcomes from

Anti-inflammatory properties of anesthetic agents

The effects of cardiopulmonary bypass following pediatric cardiac surgery

Development and validation of a score to identify cardiac surgery patients at high risk of prolonged mechanical ventilation

Early respiratory outcomes following cardiac surgery in patients with COVID-19

The authors declare that there are no conflict of interests.

http://orcid.org/0000-0001-9074-2785