1. Introduction
n late December 2019, an outbreak of pneumonia with an unknown cause was reported in parts of China that spread rapidly to other regions [1, 2]. In subsequent studies, a new type of coronavirus was identified as the causative agent of this pneumonia. The virus and the disease caused by this virus were named by the World Health Organization (WHO) as SARS-COV-2 and COVID-19, respectively [3]. On March 11, 2020, the WHO announced that the disease had become a pandemic [4]. According to the WHO’s weekly report, the frequency of diagnosed cases of COVID-19 has reached >200 million worldwide until August 2021. Besides, >4 million individuals have died due to this condition. In Iran, during this period, the number of cases of COVID-19 exceeded 4 million individuals and >95000 subjects died as a result of this disease [5].
Considering the severity of the disease and its high mortality, COVID-19 is a critical health-threatening condition. Furthermore, there is no definitive cure for this disease and most interventions are supportive; thus, prevention and rapid diagnosis are vital [15, 16]. Additionally, due to the widespread epidemic of COVID-19 around the world, especially in Iran and Gilan Province, and due to limited information about the epidemiology and clinical findings of this disease [15], we decided to review the demographic, clinical, laboratory, and imaging characteristics of critically-ill patients who were admitted to the Intensive Care Units (ICUs) of Rasht hospitals from February 20, 2020, to March 20, 2020.
2. Methods
The current retrospective, descriptive, and cross-sectional study was performed after obtaining approval from the Ethics Committee of Guilan University of Medical Sciences (Code: IR.GUMS.REC.1399.198). The study was performed on patients with COVID-19 who were admitted to the ICUs of Rasht hospitals from February 20, 2020, to March 20, 2020.
The inclusion criteria included all patients with a definitive diagnosis of COVID-19 based on a positive nasopharyngeal PCR test and hospitalization in the ICU. Moreover, the exclusion criteria included no access to patients’ medical records or inaccurate registration of information in patients’ records. We applied a census sampling method and a checklist. The necessary information was extracted from the records of the study patients applying the information system of hospitals.
In this study, patients’ demographic characteristics, including age, gender, weight, laboratory tests, including blood glucose level, serum creatinine, liver enzymes, total and direct bilirubin, complete blood cell count, lymphocyte and neutrophil count, arterial blood sample, electrolytes, albumin, lactate dehydrogenase, CRP, ESR, a history of illnesses, clinical signs at the time of admission, vital signs, including blood pressure level, heart rate, respiratory rate, body temperature, radiographic and CT scan findings, the need for a ventilator, the need for hemodialysis, the duration of hospitalization, and the patient’s treatment outcome were extracted from the patients’ medical records and consequently analyzed.
3. Results
In total, 145 patients were admitted to the ICU due to COVID-19 during the study period. Of them, 7 patients were excluded from the study due to incomplete records and the inaccurate registration of required information; finally, 138 patients were examined. The Mean±SD age of the study subjects was 62.88±13.42 years. The majority of examined patients were in the age range of 55-69 years and most cases (63.77%) were men. Diabetes mellitus, hypertension, and cardiovascular disease were the most common comorbidities with 34.78%, 32.60%, and 31.88% prevalence rates, respectively. Regarding the clinical manifestations, shortness of breath, fever, and cough were the most obvious symptoms at the onset of the disease. Based on the patient’s vital signs on admission, 101(73%) patients had a respiratory rate of >20 beats per minute, 27(19%) cases had a heart rate of >100 beats per minute, and 20(14%) patients had systolic blood pressure greater than 140 mmHg. The frequency of oxygen saturation in 92(66%) patients was less than 93%. Regarding laboratory findings, elevated Lactate Dehydrogenase (LDH), increased ESR and CRP, decreased lymphocytes, and increased neutrophils were the most common findings. In the survey of radiographic findings, most patients (80.43%) had >50% lung involvement; ground-glass opacities were the most common radiological findings in these patients. Among patients, the need for non-invasive ventilation, invasive mechanical ventilation, and hemodialysis were observed in 20(14.49%), 116(84.06%), and 12(8.70%) cases, respectively. Eventually, death occurred in 125(90.58%) patients.
4. Discussion and Conclusion
This study revealed that most patients with severe disease manifestations were elderly, had a history of underlying disease, the symptoms of shortness of breath, cough, and fever, and extensive lung involvement in imaging and changes in laboratory tests. Despite pharmacotherapy and mechanical ventilation, the mortality of the disease remains high; thus, it indicates the high severity of the disease and should be considered by the medical staff to provide services. The obtained information can be used to inform physicians to identify and evaluate patients at high risk for developing a severe form of COVID-19 and to plan for providing medical services and preventive interventions. At present, due to the short onset of the disease, the long-term complications of COVID-19 are unknown. Therefore, prospective studies are recommended to investigate these complications.  Given the prevalence of COVID-19 and the high number of deaths from the virus, further studies are required to identify effective intervention in controlling COVID-19 respiratory infection and the degree of immunity obtained from injecting vaccines produced throughout the world is essential.

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethics Committee of the Guilan University of Medical Sciences (Code: IR.GUMS.REC.1399.198). All ethical principles were considered in this research. The study participants were aware of the research process and allowed to leave the study as desired. The patient’s information was kept confidential.

Funding
This study was supported by the Deputy of Research and Technology of Guilan University of Medical Sciences, Rasht.

Authors' contributions
Conceptualization, visualization, project administration, resources, and data collection and formal analysis: All authors; Methodology, editing & review, investigation, and supervision: Mohammad Haghighi, Hossein Khoshrang, Samaneh Ghazanfar Tehran, Pegah Aghajanzadeh, Alireza Jafarinezhad; Original draft preparation: Mohammsd Haghighi, Samaneh Ghazanfar Tehran.

 Conflicts of interest
The authors declared no conflict of interest.

Acknowledgements
The authors would like to appreciate the support and constructive comments of the Deputy of Research and Technology of Guilan University of Medical Sciences, Rasht, Iran.


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