Emergency medicine is different from other disciplines in the urgency of time, and the emergency department especially emphasizes the urgency of time[9], which requires early identification and early intervention to determine the hidden dangers that threaten life and deal with them in time. In recent years, the phenomenon of emergency crowding is particularly prominent[1, 9–10]. How to identify critically ill patients at an early stage under high load and improve the accuracy of triage and evaluation is particularly important. At present, the emergency prediction of critically ill patients mostly adopts vital sign assessment method, NEWS, emergency pre-examination and triage expert consensus, adult five-level emergency triage system and so on[11–12]. In each scoring table, those with fewer indicators are convenient to use, but their accuracy may be poor, while those with more indicators improve their accuracy, but the indicators are not easy to obtain, which prolongs the triage time. Moreover, if there are more subjective indicators, it will also affect the accuracy of triage by medical staff and information systems, leading to over-triage or insufficient triage. Therefore, this study includes the predictive indicators that can be obtained in the first time in clinic, and establishes a visual prediction model for early judgment of critical risk of emergency patients, which shortens the time of emergency triage and evaluation and improves the accuracy of triage.
3.1 Risk factors of prediction model
At present, in the research on the related factors of early identification of critical emergency patients, the factors involved in identification include: temperature, HR, R, SBP, SpO2, pain score, consciousness, pupil, mental state, blood sugar, blood routine, creatinine, blood potassium, etc., but there is no consensus yet[3, 8, 13–14]. In this study, through multivariate logistic regression analysis, it is found that the risk factors for early judgment of critical risk of emergency patients are gender, age,HR, R, SBP, SpO2, consciousness, pupil, mental state and pain score, while temperature, tip, urine volume and hyperhidrosis are not independent risk factors.
The general health status of the elderly in China declines with the increase of age, and age is also an independent risk factor for various common diseases (such as diabetes, coronary heart disease, hypertension, stroke, etc.)[15–16]. Middle-aged and elderly patients account for a large proportion of emergency patients. Chung HS and other studies show that the number of emergency elderly critically ill patients and rescue operations is more than that of other adult groups[17–19]. The average age of emergency patients in this study is (50.61 ± 18.99) years, and age is also one of the risk factors in the prediction model (OR 1.044,95%CI:1.035–1.053), and the degree of critical risk is higher with the increase of age, which is consistent with the above study. Gender in this study showed that the proportion of male and female patients was similar, and the proportion of male patients was slightly higher. The results showed that male patients (OR 2.413,95%CI:1.774–3.303). The risk of critical illness is higher than that of women. Engebretsen S other studies also show that the mortality rate of men is higher than that of women, and Engebretsen S also suggest that the rate of men staying in ICU is higher than that of women, which may be related to the fact that men are still the main group of social productivity and the high-risk group of sudden serious diseases (such as cardiovascular and cerebrovascular diseases)[20–21].
HR, R, SBP, SpO2 and consciousness, as commonly used vital signs, are widely used as one of the important indicators for clinical observation of disease changes, prediction of critical illness and mortality[2–4, 8]. In the course of this study, we tried to substitute HR, R,SBP and SPO2 into continuous values in the model construction, but in clinical practice, when the first three factors are in low value and high value, they will prompt the severity of the disease, which belongs to nonlinear indicators. There is little difference in the risk degree of SPO2 in the range of 96%-100% in clinic, so these four factors are classified and assigned according to NEWS score, and they are recognized as two-category factors. Substituting into the model construction, the results show that HR, R, SBP, SPO2 and consciousness are the risk factors for early judgment of emergency critical risk, which is consistent with the research results of Kim S and Simbawa JH[13, 21]. In addition to evaluating the nervous system by observing consciousness, this study also shows that pupil size and abnormal light reflection are one of the risk factors of the prediction model (OR 6.152,95%CI:1.809–22.890). Pupil size and reflex are important monitoring parameters for patients with consciousness disorder. Minami Y and others think that pupil measurement in emergency is simpler and faster than EEG and imaging in early prediction of patients' consciousness level, but the accuracy of direct examination with flashlight is lower than that of automatic pupillometer[22–23]. so the availability and accuracy of tools for measuring pupils in actual emergency work need to be further evaluated[24].
Mental state is also a risk factor in the prediction model of this study (OR 10.403,95%CI:7.530-14.462), and its OR value is the highest among the 10 risk factors. In critical diseases such as pneumonia, acute myocardial infarction, shock, etc., it is often manifested as listlessness, but at present, domestic and foreign studies have not mentioned the role of mental state in assessing the risk of emergency critical patients, so mental state should be highly concerned in clinical work.
Pain is one of the common reasons for emergency treatment, and this study also shows that pain is one of the risk factors for predicting the critical risk of emergency treatment (OR 1.076,95%CI:1.013–1.141). Pain can cause changes in heart rate and blood pressure, and it is also a prominent manifestation of the aggravation of some diseases. Giusti GD and Hämäläinen J also think that pain is the fifth vital sign, but they also point out that there are great difficulties and diversities in the emergency assessment of acute pain[25–26]. The difference in pain scores between doctors and patients, the crowded emergency environment and the use of analgesic drugs all affect the pain assessment, which is also a place that needs close attention in the future.
In addition, temperature, tip, urine volume and hyperhidrosis are not included in the risk factors in this study. Kim S and Kushimoto S think that hypothermia is positively related to critically ill patients with sepsis, but hyperpyrexia and normal temperature have little effect on evaluation[21, 27]. This study does not show any correlation between temperature segmentation and critical risk judgment, which may be because the accuracy of axillary temperature measurement is affected by environmental temperature, emotional agitation and patient cooperation, which reduces the severity of emergency. Moreover, hyperhidrosis, tip and temperature are also greatly influenced by environmental factors and subjective factors. At present, there is no literature report that hyperhidrosis and tip are included in the study at home and abroad, so it is necessary to refine the evaluation criteria of hyperhidrosis and tip in the further study. Urine volume is an index to evaluate circulation and renal function, but it is not an index to judge critical risk in chronic renal failure, which may be the reason why urine volume is not included as a risk factor in this study.