Invasive mechanical ventilation (IMV) is a life support measure that is widely applied in clinics and greatly improves the symptoms and prognosis of patients with respiratory failure, especially for those patients with Multiple Organ Dysfunction Syndrome in the Elderly (MODSE). However, previous study had demonstrated that long duration of IMV could lead to poor outcome [
This study enrolled 6512 patients, prospectively, who were treated in multiple ICUs of the General Hospital of the People's Liberation Army (PLA) and the 8th medical center of Chinese PLA General Hospital (including the Emergency Intensive Care Unit (EICU), the Surgical Intensive Care Unit (SICU), and the Medicine Intensive Care Unit (MICU)) between January 2013 and January 2018.
The inclusion criteria were as follows: (1) the patient was 60 years of age or older and met the multiple organ dysfunction definition proposed by Marshall et al. in 1995 [
A total of 351 cases among 749 MODSE patients with complete clinical information were obtained and constituted the database of MODSE patients undergoing IMV, of which there were 327 cases of respiratory failure, 288 cases of heart failure, 245 cases of renal failure, 159 cases of liver failure, 74 cases of gastrointestinal dysfunction, 203 cases of neurological dysfunction, and 194 cases of coagulation disorders. Among the study subjects, there were 274 cases which were allowed to wean from MV, as they met the conditions for weaning, whereas 77 did not meet the standard during the ICU stay (Figure
Flowchart of patient enrollment in this study.
All participants signed an informed consent upon admission to the ICUs. This study was approved by the Clinical Ethics Committee of the General Hospital of the PLA.
Among the 749 enrolled MODSE patients, 351 patients who were undergoing IMV were analyzed prospectively. Many disease information should be collected, including the worst parameter among various vital signs (body temperature, heart rate, respiratory rate, blood pressure, urine volume, etc.), laboratory test results (blood routine, blood biochemistry, and coagulation parameters), and the clinical data (gender, age, ICU entry diagnosis, ICU stay duration, underlying disease). In addition, the APACHE II, APACHE III, SAPS II, and MODS results were calculated for the participants within 24 h after their ICU entry. Based on the outcomes upon ICU discharge, the participants were divided into a survival group and a nonsurvival group. Based on weaning criteria, the participants were divided into a weaning group (274 cases) and a nonweaning group (77 cases); depending on whether weaning would be successful, the weaning eligible individuals were further divided into a successful-weaning group (105 cases) and a failure-to-wean group (169 cases). If the datum for a parameter was missing, it was considered to be a default value of normal. ICU discharge (survival or death) was adopted as the observation end point. Multivariate logistic regression was performed to analyze individual parameters to identify the factors influencing weaning.
The weaning criteria previously reported [
The criteria of successful weaning included the following [
The criteria of failed weaning were as follows: reintubation within 48 hours, a participant was considered to experience weaning failure if he/she died or needed to receive another procedure of MV.
SPSS 17.0 software was employed herein for statistical analyses. Measurement data consistent with a normal distribution were all expressed as means ± standard deviations (
Among the 749 enrolled MODSE patients from 6 ICU-centers, 351 (46.83%) were received IMV and had a mean age of 77.7 ± 9.2 years. Of the 351 patients, there were 254 males (72.46%) and 97 females (27.64%); there were 102 survivors (29.06%) and 249 nonsurvivors (70.94%) based on the outcome of 28-day; there were 274 individuals who met the ventilator weaning criteria (78.06%), including 105 cases (76 survivals and 29 deaths) of successful weaning (38.32% of the 274) and 169 cases (26 survivals and 143 deaths) of failed weaning (61.68% of the 274); and there were 64 participants undergoing tracheotomy (26 in the weaning failure subgroup, and 38 in the nonweaning group). These general statistics are summarized in Table
General clinical information of the enrolled patients.
Total | 28-day survivors ( |
28-day nonsurvivors ( |
|
|
---|---|---|---|---|
Age (years) | 77.71 ± 9.22 | 77.52 ± 9.18 | 77.86 ± 9.24 | 0.816 |
Gender (no., %) | ||||
Male | 254 | 72 | 182 (71.65%) | 0.781 |
Female | 97 | 30 | 67 (69.07%) | |
Number of failing organs |
3.82 ± 1.22 | 3.14 ± 1.03 | 4.09 ± 1.19 | <0.001 |
Vital signs and laboratory tests | ||||
Body temperature (°C) |
37.81 ± 1.40 | 37.45 ± 1.25 | 37.95 ± 1.44 | 0.021 |
Heart rate (times/min) |
114.7 ± 29.2 | 104.3 ± 26.1 | 118.9 ± 29.4 | 0.001 |
Breathing rate (times/minute) |
24.5 ± 6.7 | 22.6 ± 5.6 | 25.3 ± 7.0 | 0.006 |
Mean arterial pressure (mmHg) | 77.5 ± 22.6 | 82.1 ± 22.4 | 75.6 ± 22.5 | 0.070 |
Urine output (mL/24 hours) |
1671.7 ± 1392.1 | 1371.8 ± 181.7 | 1332.1 ± 112.6 | <0.001 |
WBC count (109/L) |
12.95 ± 8.20 | 11.19 ± 5.56 | 13.66 ± 8.98 | 0.021 |
Platelet count (109/L) |
126.5 ± 74.7 | 150.8 ± 69.3 | 116.7 ± 74.8 | 0.003 |
PaO2/FiO2 |
156.0 ± 85.0 | 180.7 ± 96.2 | 142.3 ± 76.2 | <0.001 |
Serum creatinine ( |
194.2 ± 173.0 | 141.5 ± 130.0 | 215.7 ± 183.7 | 0.002 |
Serum sodium (mmol/L) |
140.05 ± 8.72 | 137.71 ± 7.01 | 141.00 ± 9.18 | 0.016 |
Serum potassium (mmol/L) |
4.22 ± 1.10 | 3.78 ± 0.80 | 4.40 ± 1.16 | <0.001 |
Serum albumin (g/L) | 30.42 ± 8.72 | 32.32 ± 10.71 | 29.65 ± 7.68 | 0.050 |
Serum bilirubin ( |
31.82 ± 61.00 | 16.43 ± 12.42 | 38.08 ± 71.05 | 0.001 |
Scoring systems | ||||
APACHE II |
25.6 ± 8.2 | 18.8 ± 6.1 | 28.4 ± 7.4 | <0.001 |
APACHE III |
96.5 ± 31.4 | 71.1 ± 24.6 | 106.9 ± 27.8 | <0.001 |
SAPS II |
61.9 ± 17.8 | 48.1 ± 13.3 | 67.6 ± 16.3 | <0.001 |
MODS |
8.7 ± 3.5 | 5.9 ± 2.5 | 9.9 ± 3.2 | <0.001 |
Outcomes of weaning |
||||
Success | 105 | 76 | 29 (27.94%) | <0.001 |
Failure | 169 | 26 | 143 (84.62%) | |
The length of ICU stay (days) |
20.93 ± 21.69 | 17.67 ± 19.99 | 28.95 ± 23.71 | 0.001 |
Quantitative data of normal distribution are presented as mean ± SD. Qualitative data are presented as
Based on the survival/death upon discharge (or ICU discharge), prognosis was assessed using the worst scores (APACHE II, APACHE III, SAPS II, and MODS) during the first 24 h of ICU entry, before the ROC curve was plotted. The score corresponding to the maximal Youden index was set as the optimal cutoff value, whereby the individual sensitivities, specificities, Youden indices, AUCs, and 95% confidence intervals were calculated (Table
Comparison of the diagnostic indicators of the prognostic scoring systems.
Scoring models | Cutoff | Se | Sp | Youden index | AUC | 95% CI |
---|---|---|---|---|---|---|
APACHE II | 25.5 | 0.769 | 0.856 | 0.604 | 0.837 | 0.768–0.898 |
APACHE III | 86.0 | 0.748 | 0.809 | 0.557 | 0.833 | 0.752–0.890 |
SAPS II | 57.5 | 0.698 | 0.762 | 0.420 | 0.784 | 0.706–0.832 |
MODS | 6.5 | 0.816 | 0.827 | 0.643 | 0.860 | 0.797–0.916 |
Se: sensitivity; Sp: specificity; ROC curve: receiver operating characteristic curve; AUC: area under the curve; 95% CI: 95% confidence interval.
The ROC curves for predicting prognosis of 28-day survivors and 28-day nonsurvivors.
Depending on the weaning outcome, the subjects were divided into a weaning success subgroup and a weaning failure subgroup. The prognostic differences of the two subgroups were evaluated (Table
Different prognostic outcomes of patients from different weaning groups/subgroups.
Successful-weaning ( |
Failure-to-wean ( |
||
---|---|---|---|
Age (years) | 76.5 ± 9.6 | 79.5 ± 8.8 | 0.050 |
Gender (no., %) | |||
Male | 67 | 136 | 0.067 |
Female | 38 | 33 | |
Underlying disease (no., %) | |||
Underlying lung disease |
26 | 82 | <0.001 |
Coronary heart disease | 41 | 72 | 0.502 |
Hypertension | 46 | 79 | 0.556 |
Diabetes | 31 | 58 | 0.297 |
Number of failing organs |
3.2 ± 1.0 | 3.9 ± 1.2 | <0.001 |
Outcome of 28-day |
0.001 | ||
Survivors | 76 | 26 | |
Nonsurvivors | 29 | 143 | |
The length of ICU stay (days) |
19.4 ± 13.1 | 26.8 ± 24.4 | 0.034 |
Logistic regression analysis of dichotomous variables was performed to screen the factors influencing weaning. First, the 274 weaning-eligible patients were divided into a weaning success subgroup and a weaning failure subgroup. Their clinical data were subsequently documented, including their gender, age, number of organs with failure, concurrent diseases (e.g., hypertension, diabetes, chronic obstructive pulmonary disease, coronary heart disease, and immunosuppression), worst vital sign within 24 h of ICU entry, and laboratory test results. These parameters were then introduced into univariate and multivariate logistic regression equations of dichotomous variables. Underlying lung disease, plasma albumin, serum creatinine level, number of organs with failure, and IMV duration fit into the regression equation, indicating that the five parameters were independent factors influencing the weaning success rate for MODSE patients receiving IMV, with odds ratios (ORs) of 1.447, 0.820, 1.603, 2.374, and 3.105, respectively (Table
Logistic regression analysis for MODSE patients with IMV.
Variable | B | Se | Wald | d |
|
OR | 95% CI |
---|---|---|---|---|---|---|---|
Underlying lung disease | 0.439 | 0.156 | 6.796 | 1 | 0.001 | 1.447 | 1.098–1.816 |
Serum albumin | -0.085 | 0.033 | 5.890 | 1 | 0.021 | 0.820 | 0.732–0.924 |
Serum creatinine | 0.004 | 0.003 | 2.913 | 1 | 0.036 | 1.603 | 1.210–1.974 |
Duration of MV | 1.475 | 0.327 | 7.372 | 1 | 0.001 | 2.441 | 1.742–2.837 |
The number of failing organs | 0.427 | 0.141 | 9.876 | 1 | 0.001 | 3.105 | 2.313–3.795 |
MODSE refers to conditions in which elderly individuals with multiple underlying diseases experience decreased organ function and reserve capacity. As a consequence, they are vulnerable to infections and display aggravated progression, leading to critical conditions that urgently require multiple organ support therapy (MOST). In this study, 53.97% of the MODSE patients underwent the life support treatment of IMV to alleviate symptoms and improve prognosis. However, long-term IMV may lead to ventilator dependence and difficulty in weaning, which elevates medical expenditure, decreases quality of life, and increases mortality.
Our data from multiple centers revealed that MODSE patients receiving IMV had poor prognosis and a high mortality rate of 71.07%. Comparison between the mortality group and the survival group revealed that the former had a slightly higher mean age, but the difference was not significant (
A scoring system consists of a set of objective quantitative indicators to evaluate disease severity and to assess prognosis. Its results indicate the degree of disease severity and the body’s physiological dysfunction and can reliably reveal critical conditions and predict mortality risk [
Early weaning and extubation followed by spontaneous breathing is the eventual goal of MV [
To investigate the factors influencing weaning, multivariate logistic regression analyses of dichotomous variables were performed to identify indicators related to weaning success, which included underlying lung disease, plasma albumin, serum creatinine level, number of organs with failure, and MV duration, with ORs of 1.447, 0.820, 1.603, 2.374, and 3.105, respectively. As such, the data indicated that a high plasma albumin level is an independent protective factor for MODSE patients to wean from MV. In contrast, the other indicators (i.e., underlying lung disease, serum creatinine level, number of organs with failure, and MV duration) were risk factors affecting MODSE patients’ weaning.
Plasma albumin can reliably reveal a patient’s recent nutritional status. Under MV, the body is under stress conditions associated with robust energy consumption, metabolism, and decomposition activity, which can lead to relative malnutrition, manifested by a decreased plasma albumin level. In response, the body degrades respiratory muscle to compensate the energy deficit, which results in respiratory muscle atrophy and decreased muscle strength. Correspondingly, weaning from MV may cause respiratory muscle fatigue and, in turn, increase the risk of weaning failure [
In addition, it was reported that MV duration is also a crucial factor influencing whether weaning can be successful [
In summary, the weaning of MODSE patients undergoing IMV is affected by complex and multisided factors. For these patients, it is important to actively provide impaired organs with functional support and to ameliorate or improve organ failure, thereby reducing the influences of intrapulmonary factors on weaning. In addition, it is also crucial to treat the primary disease, augment nutritional support, and improve the patient’s condition. Among the critical scoring systems tested in this study, MODS exhibited the best performance of prognosis assessment for MODSE patients undergoing MV and is recommended for clinical application. Nevertheless, most indicators employed herein were extrapulmonary parameters, whereas intrapulmonary parameters, such as the rapid shallow breathing index [
The clinical data used to support the findings of this study have not been made available because of the protection of patient privacy.
The authors declare that they have no conflicts of interest.
Kun Xiao and Bin Liu have contributed equally to this work.
The authors express their gratitude to the nurses and doctors of the EICU, MICU, and SICU of the General Hospital of the People’s Liberation Army (PLA) and the 8th medical center of Chinese PLA General Hospital for their help with this study. This work was supported by Clinical Support Fund of Chinese PLA general hospital (no. 15KMM03), Young Talents Support Project of Military science and Technology (no. 17-JCJQ-QT-036), and Major Science and Technology Projects for the 13th Five-Year Plan (2018ZX09201013).