Orthopedics

Feature Article 

Intensive Care Unit Resource Utilization After Hip Fracture Surgery in Elderly Patients: Risk Factor Identification and Risk Stratification

Zhenggang Guo, MD; Feng Zhao, MD; Ye Wang, MD; Xiaoyan Wang, MD

Abstract

The objective of this study was to develop a risk stratification index (RSI) system to guide intensive care unit (ICU) resource use for elderly patients after hip fracture surgery. The authors' first study cohort consisted of 302 elderly patients with hip fractures who had surgical treatment at their hospital. The authors conducted multivariate logistic regression analysis to investigate relevant risk factors for ICU resource utilization postoperatively. An RSI system was developed based on the significant risk factors from regression analysis. A second study cohort consisted of 205 elderly patients, among whom the authors applied the RSI system to guide ICU resource assignment. Among the first cohort of 302 hip fracture patients, 89 were transferred to ICU postoperatively, of whom 81 were planned to be transferred to ICU and 8 were not. Multivariate stepwise regression analysis revealed that age (≥80 years), preoperative pulmonary disease, perioperative anemia (hemoglobin <8 g/dL), and perioperative lactic acid level (>2 mmol/L) were independent risk factors for postoperative ICU management. The authors then constructed a weighted RSI with these risk factors. In addition, they manually added American Society of Anesthesiologists classification (III/IV) and types of anesthesia as additional risk factors based on their clinical experience. It was determined that an RSI score greater than 4 required postoperative ICU care. The RSI system was then prospectively applied to an independent cohort of 205 elderly surgical patients with hip fractures, among whom only 40 required ICU care. More importantly, there were no later transfers from the general ward to ICU after the application of RSI. The RSI system is effective for guiding postoperative ICU transfer without compromising patient care and minimizes unexpected transfers from the general ward to the postoperative ICU. [Orthopedics. 2020;43(x):xx–xx.]

Abstract

The objective of this study was to develop a risk stratification index (RSI) system to guide intensive care unit (ICU) resource use for elderly patients after hip fracture surgery. The authors' first study cohort consisted of 302 elderly patients with hip fractures who had surgical treatment at their hospital. The authors conducted multivariate logistic regression analysis to investigate relevant risk factors for ICU resource utilization postoperatively. An RSI system was developed based on the significant risk factors from regression analysis. A second study cohort consisted of 205 elderly patients, among whom the authors applied the RSI system to guide ICU resource assignment. Among the first cohort of 302 hip fracture patients, 89 were transferred to ICU postoperatively, of whom 81 were planned to be transferred to ICU and 8 were not. Multivariate stepwise regression analysis revealed that age (≥80 years), preoperative pulmonary disease, perioperative anemia (hemoglobin <8 g/dL), and perioperative lactic acid level (>2 mmol/L) were independent risk factors for postoperative ICU management. The authors then constructed a weighted RSI with these risk factors. In addition, they manually added American Society of Anesthesiologists classification (III/IV) and types of anesthesia as additional risk factors based on their clinical experience. It was determined that an RSI score greater than 4 required postoperative ICU care. The RSI system was then prospectively applied to an independent cohort of 205 elderly surgical patients with hip fractures, among whom only 40 required ICU care. More importantly, there were no later transfers from the general ward to ICU after the application of RSI. The RSI system is effective for guiding postoperative ICU transfer without compromising patient care and minimizes unexpected transfers from the general ward to the postoperative ICU. [Orthopedics. 2020;43(x):xx–xx.]

Hip fractures are proximal femoral fractures that include the following 3 major types: femoral neck fractures, intertrochanter fractures of the femur, and subtrochanteric fractures. More than 1 million hip fractures have occurred annually worldwide since 1990. This number is expected to rise to 2.6 million by 2025. Major demographic changes will occur in Asia, where 26% of all hip fractures occurred worldwide in 1990. However, this figure is expected to increase to 37% by 2025.1 In the capital city of Beijing, China, women and men older than 70 years were 3.37 times and 2.01 times more likely to have hip fractures, respectively, than younger populations.2 With the aging population, the increased burden of comorbidity also needs to be managed along with hip fractures. Nonsurgical treatment is not preferred due to serious complications, such as pressure ulcers and pneumonia, which carry high morbidity and mortality risks.3 At the authors' hospital, the implementation of early surgical treatment for suitable hip fracture patients, followed by early function rehabilitation, has been promoted in recent years. The goal is to reduce patients' complications while simultaneously reducing the health care cost.

Hip fracture is a common orthopedic disease in the elderly (65 years or older), with mortality rates as high as 36% within 1 year, and an average reduced life expectancy of 1.8 years.4–6 Other perioperative complications that can also significantly jeopardize the quality of patient recovery include pneumonia, urinary retention, anemia, and others.7–9 Early effective treatment and perioperative management promote mobilization and rehabilitation, which subsequently help to reduce perioperative risks. The comorbidity burden of selected patients might indicate intensive care unit (ICU) level of care, with experienced well-trained intensivist specialists and other resources reducing severe postoperative complications and mortality.10 It is clear, however, that when patients are transferred to the ICU after surgery, associated total hospital charges also increase dramatically.11 Therefore, how to balance optimal clinical care and health care cost was the focus of this study.

Whether patients are assigned to the ICU depends mainly on the clinical judgment of the managing team, without a quantitative matrix to guide ICU resource assignment.10,12–14 It was the authors' goal, therefore, to study the risk factors in elderly patients with hip fractures who were transferred postoperatively to the ICU and to develop a risk stratification index (RSI) system to guide ICU assignment. In addition, the authors conducted a prospective study to test the efficiency and safety of the RSI.

Materials and Methods

Sample Size

The authors first conducted a chart review from February 2016 to March 2016, which included 22 hip fracture patients with 5 (22.72%) ICU transfers. Therefore, based on preliminary observations and prior literature, it was assumed that the expected positive rate (ϖ) was 20%, the allowable error E was 5%, and the confidence level 1-α was 95%. The eventual estimated sample size should be a minimum of 246 cases (Figure 1).

Formula for calculating the minimum sample size.

Figure 1:

Formula for calculating the minimum sample size.

This study received institutional review board approval. The chart review of the first cohort of 302 patients was covered by a hospital quality and improvement project, and patient consent was waived. Written informed consent was obtained from the second group of 205 elderly patients who were prospectively studied.

Patient Selection

The authors identified a cohort of 312 patients based on Current Procedural Terminology codes (S72.001; S72.104; S72.201) from March 2016 to May 2017. Patients admitted to the ICU before surgery were excluded from the study (n=10). Of the 302 elderly patients who met the inclusion criteria, 89 were males and 213 were females, with a mean age of 79.34±7.36 years. Eighty-nine patients were transferred to the ICU postoperatively, of whom 81 were planned to be transferred to the ICU and 8 were not. The patients were divided into an ICU group (n=89) and a control group (n=213) according to their status of ICU transfer after surgery. Postoperative ICU transfer was defined as those elderly patients with hip fractures who were admitted to the ICU within 24 hours after surgery. This study was open labeled, without limitation of perioperative treatment measures.

Independent Variables

Perioperative risk factors for ICU admission included the following categories: (1) demographic information: sex, age, height, and weight; (2) comorbidities: American Society of Anesthesiologists (ASA) classification, coronary heart disease, hypertension, diabetes mellitus, pneumonia, emphysema, pulmonary hypertension, and cerebrovascular disease with functional impairment; (3) intraoperative factors: type of operation, type of anesthesia, operative time, intraoperative lowest hemoglobin, intraoperative lactic acid level, total infusion volume, blood loss, and blood transfusion; (4) postoperative event: liver function abnormality (bilirubin ≥2.5 mg/dL), renal injury creatinine (≥2 mg/dL), any coagulation abnormality (prothrombin time, international normalized ratio, activated partial thromboplastin time, thrombin time, and fibrinogen), length of hospital stay, medical cost, and mortality; and (5) emergency admission status.

Statistical Methods

Stata 14.0 statistical software (Stata-Corp LP, College Station, Texas) was used for data analysis. Measurement data were expressed as mean and standard deviation, and t test was used to compare groups. Categorical data were represented by sample rate or constituent ratio, and chi-square test was adopted for comparison between groups. Multivariate backward stepwise logistic regression analysis was applied to identify independent risk factors (exclusion of variables with P>.05). To avoid multicollinearity among variables, variables of variance inflation factor greater than 2 were excluded. The statistical significance was adjusted using the Bonferroni correction (2-sided) at P<.0083 (0.05/6 comparisons) to account for the multiple models examined in this study.

Results

The authors' first study cohort consisted of 302 patients, of whom 89 were transferred to the ICU. Table 1 summarizes patient characteristics of the ICU group and the control group. The ICU group included more patients aged 80 years or older (64 of 89 [71.91%] vs 98 of 213 [46.01%]; P=.000), ASA III/IV (70 of 89 [78.65%] vs 97 of 213 [45.54%]; P=.000), emergency admission (19 of 89 [21.35%] vs 20 of 213 [9.39%]; P=.005), pulmonary disease (66 of 89 [74.16%] vs 60 of 213 [28.17%]; P=.000), and cerebrovascular disease (19 of 89 [21.35%] vs 14 of 213 [6.57%]; P=.000). The ICU group also had a longer operative time (>120 minutes; 22 of 89 [24.72%] vs 35 of 213 [16.43%]; P=.093), greater blood loss (248.09±278.99 vs 190.31±272.47 mL; P=.096), more blood transfusion (52 of 89 [58.43%] vs 104 of 213 [48.83%]; P=.128), a higher incidence of intraoperative anemia (57 of 89 [64.04%] vs 9 of 213 [4.23%]; P=.000), and an elevated lactic acid level (75 of 89 [84.27%] vs 31 of 213 [14.55%]; P=.000). The ICU group also was more likely to receive general anesthesia (65 of 89 [73.03%] vs 107 of 213 [50.23%]; P<.05).

Single-Factor Analysis for Postoperative Transfer to the ICU

Table 1:

Single-Factor Analysis for Postoperative Transfer to the ICU

There were several risk factors with statistical significance, including age (≥80 years), preoperative pulmonary disease, perioperative anemia (hemoglobin <8 g/dL), and perioperative lactic acid level (>2 mmol/L) (Table 2). The authors established a weighted RSI model based on the odds ratio (OR) of the corresponding independent risk factors. In addition, they added ASA classification (III/IV) and types of anesthesia as additional risk factors based on their clinical experience. To simplify the model for clinical use, the authors assigned weight of 1, 2, or 3 corresponding to OR of 1 to 10, greater than 10 to 20, or greater than 20, respectively (age, 1; ASA [III/IV], 1; anesthesia method [general], 1; preexisting pulmonary disease, 1; perioperative lactic acid level >2 mmol/L, 2; perioperative anemia, 3). Simulation analysis on the 302 patients showed that the highest RSI score was 9 (Table 2). The ICU postoperative transfer rates were 0%, 0%, 1.41%, 4.35%, 43.48%, 70%, 77.78%, 92.86%, 100%, and 92.86% corresponding to RSI score from 0 to 9, respectively (Figure 2). The incidence of postoperative ICU transfer was significantly higher when the RSI was 4 or greater (Figure 2). Therefore, the authors selected an RSI of 4 as the cutoff value for ICU transfer (Figure 2).

Risk Factors for Postoperative Transfer to the ICU

Table 2:

Risk Factors for Postoperative Transfer to the ICU

The intensive care unit (ICU) postoperative transfer rates were 0%, 0%, 1.41%, 4.35%, 43.48%, 70%, 77.78%, 92.86%, 100%, and 92.86% corresponding to a risk stratification index (RSI) score from 0 to 9, respectively. The incidence of postoperative ICU transfer was significantly higher when the RSI was 4 or greater.

Figure 2:

The intensive care unit (ICU) postoperative transfer rates were 0%, 0%, 1.41%, 4.35%, 43.48%, 70%, 77.78%, 92.86%, 100%, and 92.86% corresponding to a risk stratification index (RSI) score from 0 to 9, respectively. The incidence of postoperative ICU transfer was significantly higher when the RSI was 4 or greater.

For the 302 patients undergoing surgery for hip fractures, postoperative complications of pulmonary infection were significantly increased in the ICU group (P<.05) compared with the control group. However, there were no significant differences in the incidence of other complications such as hepatic and renal function impairment and coagulation disorders. Additionally, although the ICU group's length of hospital stay did not increase, mortality and total hospital charges increased significantly (P=.0001). Of the 89 elderly patients with hip fractures who were transferred to the ICU, 81 patients (9 deaths) were scheduled to be transferred directly to the ICU after surgery; the remaining 8 cases (5 deaths) were unplanned transfers from the ward to the ICU within 24 hours (Table 3). Among the 89 elderly patients, the mortality rate for patients who were not planned ICU postoperative transfers was significantly increased (5 of 8 [62.5%] vs 9 of 81 [11.1%]; P=.001). The RSI was then prospectively applied to 205 elderly patients with hip fractures undergoing surgery. The patterns of complications were similar to the first cohort of 302 patients, including pulmonary infection (P=.0012) and other complications. There were 8 deaths in the ICU group, and none of these regular floor patients required emergent ICU-level care (P=.0000) (Table 4). Cross-comparison of the ICU patients in the 2 cohorts revealed no statistical significance regarding pattern of outcomes (Table 5). There were 40 patients with an RSI of 4 or greater who were transferred to the ICU. The RSI can simplify ICU assignment, reduce the number of patients transferred to the ICU postoperatively (P=.0115), decrease average total hospital charges by 2.40%, and minimize transfers from the general floor to the ICU within 24 hours after hip fracture surgery in elderly patients (8 of 302 [2.65%] vs 0 of 205 [0%]; P=.0470) (Table 6).

Comparison of Outcomes Between the ICU Group and the Control Group (302 Patients)

Table 3:

Comparison of Outcomes Between the ICU Group and the Control Group (302 Patients)

Comparison of Outcomes Between the ICU Group and the Control Group (205 Patients)

Table 4:

Comparison of Outcomes Between the ICU Group and the Control Group (205 Patients)

Comparison of Outcomes Between the Non-RSI Group and the RSI Group Among ICU Patients

Table 5:

Comparison of Outcomes Between the Non-RSI Group and the RSI Group Among ICU Patients

Comparison of Outcomes Between the Non-RSI Group and the RSI Group

Table 6:

Comparison of Outcomes Between the Non-RSI Group and the RSI Group

Discussion

The ICU is a valuable resource for patients with unstable and/or severe medical conditions. Selected elderly patients with hip fractures usually carry significant comorbidities and might benefit from ICU management during the perioperative period.10,11 However, ICU service is associated with significantly higher increases in total hospital charges and out-of-pocket expenses, especially because patients in China need to self-pay a considerable proportion of their medical bills. How to balance health care costs and optimal clinical care was the focus of this study. Of the 302 elderly surgical patients with hip fractures in the testing cohort, 81 (26.82%) were planned ICU postoperative transfers, and the remaining 8 (2.65%) were unplanned ICU transfers within 24 hours postoperatively. Of the 14 mortalities, 5 were unplanned ICU transfers from the ward. Although these transfers might have been due to the natural progression of the patients or delays in treatment, an internal review at the hospital of these cases indicated that some events could potentially be minimized if early ICU intervention was established. All of these highlight the importance of minimizing depriving patients of ICU-level care when indicated.

Hip fractures have drawn broad attention worldwide, and researchers have identified many confounding factors seriously affecting the prognosis, including demographic information (eg, age, sex, ethnicity, body mass index), preexisting comorbidities (eg, chronic obstructive pulmonary disease, congestive heart failure, dyspnea), ASA classification, and certain abnormal laboratory test results before surgery.15–18 However, no study has focused on ICU resource use. In this study, the authors found that age (≥80 years), preoperative pulmonary disease, and intraoperative factors (hemoglobin <8 g/dL; lactic acid level >2 mmol/L) were independent risk factors for elderly surgical patients with hip fractures requiring ICU postoperative management.

Given the complexity of comorbidities in elderly patients with hip fractures, reasonable individualized anesthesia management should be determined according to postoperative complications, the patient's functional status, and health-related quality of life.19 Although the application of general anesthesia has been decreasing in elderly patients with hip fractures, 172 (56.95%) patients received general anesthesia in the current study (OR, 3.87; 95% confidence interval [CI], 1.25–12.04).20 Moreover, the ratio of ICU transfer in patients who received general anesthesia was significantly higher than that of combined spinal epidural anesthesia (37.79% vs 18.46%; P<.001). In perioperative management, severe anemia (<8 g/dL; OR, 38.16; 95% CI, 10.37–140.39) can lead to insufficient oxygen supply to the heart, brain, and other vital organs and tissues, especially in elderly patients with ischemic heart disease. Similarly, blood lactate level is an indicator of oxygenation, perfusion, and metabolism of tissue (variance inflation factor=1.55). The value of blood lactic acid measurement (>2 mmol/L) is considered as the standard of emergency classification in major trauma medical centers, which is consistent with the current study's significance (OR, 17.98; 95% CI, 6.81–47.49).21

Generally, clinicians believe that most pulmonary complications are associated with persistent pneumonia caused by prolonged bed rest. Actually, with improvements in surgical methods, the time of bed rest has been greatly reduced, but postoperative complications have not remarkably decreased in elderly patients with hip fractures.22 It may be related to multiple organ failure in the elderly, of which pulmonary dysfunction is the key link in its initiation.23 In the current study, it was noteworthy that the incidence of pulmonary infection increased significantly when patients were transferred to the ICU (14.61% vs 8.92%; P=.0000), which might indicate the severity of medical conditions in this group of patients.

There are several commonly used clinical evaluation systems for hip fracture patients, including the Nottingham Hip Fracture Score, Surgeons-National Surgical Quality Improvement Program-Surgical Risk Calculator, Acute Physiology and Chronic Health Evaluation (APACHE)-III, and Modified Early Warning Score. Although these indicators can predict the prognosis of patients, the clinical management flow is extremely complicated, and it has not been applied to resource assignment after surgery, including ICU use. In this study, the established RSI was applied to 205 elderly patients with hip fractures to guide decision making regarding postoperative destination, and satisfactory results were achieved with no emergent transfer from the general ward to the ICU afterward.

This study had several limitations. First, it was a single-center study, and the outcome might not be applicable to other institutions. Second, the study focused on the available variables in the database and might have missed other interesting factors. Third, the classification of hip fractures surgery was not analyzed, which might result in insufficient analysis of risk factors due to the difference in severity of surgical insult.

Conclusion

Multivariate backward stepwise logistic regression analysis shows that age (≥80 years), preoperative pulmonary disease, perioperative anemia (hemoglobin <8 g/dL), and perioperative lactic acid level (>2 mmol/L) were independent risk factors for elderly patients with hip fractures transferred postoperatively to the ICU. In clinical practice, a formulated RSI system based on the OR value of clinical variables and clinical experience can effectively guide prognosis and management decision making for elderly patients with hip fractures.

References

  1. Gullberg B, Johnell O, Kanis JA. Worldwide projections for hip fracture. Osteoporos Int. 1997;7(5):407–413. doi:10.1007/PL00004148 [CrossRef]
  2. Xia WB, He SL, Xu L, et al. Rapidly increasing rates of hip fracture in Beijing, China. J Bone Miner Res. 2012;27(1):125–129.
  3. Colloca G, Santoro M, Gambassi G. Age-related physiologic changes and perioperative management of elderly patients. Surg Oncol. 2010;19(3):124–130. doi:10.1016/j.suronc.2009.11.011 [CrossRef] PMID:20004566
  4. Roche JJ, Wenn RT, Sahota O, Moran CG. Effect of comorbidities and postoperative complications on mortality after hip fracture in elderly people: prospective observational cohort study. BMJ. 2005;331(7529):1374. doi:10.1136/bmj.38643.663843.55 [CrossRef] PMID:16299013
  5. Abrahamsen B, van Staa T, Ariely R, Olson M, Cooper C. Excess mortality following hip fracture: a systematic epidemiological review. Osteoporos Int. 2009;20(10):1633–1650. doi:10.1007/s00198-009-0920-3 [CrossRef]
  6. Johnell O, Kanis JA. An estimate of the worldwide prevalence, mortality and disability associated with hip fracture. Osteoporosis International. 2004;15(11):897–902. doi:10.1007/s00198-004-1627-0 [CrossRef]
  7. Belmont PJ Jr, Garcia EJ, Romano D, Bader JO, Nelson KJ, Schoenfeld AJ. Risk factors for complications and in-hospital mortality following hip fractures: a study using the National Trauma Data Bank. Arch Orthop Trauma Surg. 2014;134(5):597–604. doi:10.1007/s00402-014-1959-y [CrossRef] PMID:24570142
  8. Lv H, Yin P, Long A, et al. Clinical characteristics and risk factors of postoperative pneumonia after hip fracture surgery: a prospective cohort study. Osteoporos Int. 2016;27(10):3001–3009. doi:10.1007/s00198-016-3624-5 [CrossRef]
  9. Folbert EC, Hegeman JH, Gierveld R, et al. Complications during hospitalization and risk factors in elderly patients with hip fracture following integrated orthogeriatric treatment. Arch Orthop Trauma Surg. 2017;137(4):507–515. doi:10.1007/s00402-017-2646-6 [CrossRef] PMID:28233062
  10. Ghaffar S, Pearse RM, Gillies MA. ICU admission after surgery: who benefits?Curr Opin Crit Care.2017;23(5):424–429. doi:10.1097/MCC.0000000000000448 [CrossRef] PMID:28777159
  11. Irone M, Parise N, Bolgan I, Campostrini S, Dan M, Piccinni P. Assessment of adequacy of ICU admission. Minerva Anestesiol. 2002;68(4):201–207. PMID:12024083
  12. Marufu TC, White SM, Griffiths R, Moonesinghe SR, Moppett IK. Prediction of 30-day mortality after hip fracture surgery by the Nottingham Hip Fracture Score and the Surgical Outcome Risk Tool. Anaesthesia. 2016;71(5):515–521. doi:10.1111/anae.13418 [CrossRef] PMID:26940757
  13. Goltz DE, Baumgartner BT, Politzer CS, DiLallo M, Bolognesi MP, Seyler TM. The American College of Surgeons National Surgical Quality Improvement Program surgical risk calculator has a role in predicting discharge to post-acute care in total joint arthroplasty. J Arthroplasty. 2018;33(1):25–29.
  14. Qin Q, Xia Y, Cao Y. Clinical study of a new Modified Early Warning System scoring system for rapidly evaluating shock in adults. J Crit Care. 2017;37:50–55. doi:10.1016/j.jcrc.2016.08.025 [CrossRef] PMID:27626832
  15. Flikweert ER, Wendt KW, Diercks RL, et al. Complications after hip fracture surgery: are they preventable?Eur J Trauma Emerg Surg.2018;44(4):573–580.
  16. Jürisson M, Raag M, Kallikorm R, Lember M, Uusküla A. The impact of comorbidities on hip fracture mortality: a retrospective population-based cohort study. Arch Osteoporos. 2017;12(1):76. doi:10.1007/s11657-017-0370-z [CrossRef] PMID:28849347
  17. Wiklund R, Toots A, Conradsson M, et al. Risk factors for hip fracture in very old people: a population-based study. Osteoporos Int. 2016;27(3):923–931. doi:10.1007/s00198-015-3390-9 [CrossRef]
  18. Lewis PM, Waddell JP. When is the ideal time to operate on a patient with a fracture of the hip?: a review of the available literature. Bone Joint J. 2016;98-B(12):1573–1581. doi:10.1302/0301-620X.98B12.BJJ-2016-0362.R2 [CrossRef] PMID:27909117
  19. Roberts KC, Brox WT, Jevsevar DS, Sevarino K. Management of hip fractures in the elderly. J Am Acad Orthop Surg. 2015;23(2):131–137. doi:10.5435/JAAOS-D-14-00432 [CrossRef] PMID:25624365
  20. Patorno E, Neuman MD, Schneeweiss S, Mogun H, Bateman BT. Comparative safety of anesthetic type for hip fracture surgery in adults: retrospective cohort study. BMJ. 2014;348:g4022. doi:10.1136/bmj.g4022 [CrossRef] PMID:24972901
  21. Bou Chebl R, El Khuri C, Shami A, et al. Serum lactate is an independent predictor of hospital mortality in critically ill patients in the emergency department: a retrospective study. Scand J Trauma Resusc Emerg Med. 2017;25(1):69. doi:10.1186/s13049-017-0415-8 [CrossRef] PMID:28705203
  22. Haleem S, Lutchman L, Mayahi R, Grice JE, Parker MJ. Mortality following hip fracture: trends and geographical variations over the last 40 years. Injury. 2008;39(10):1157–1163. doi:10.1016/j.injury.2008.03.022 [CrossRef] PMID:18653186
  23. Ma RS, Gu GS, Huang X, et al. Postoperative mortality and morbidity in octogenarians and nonagenarians with hip fracture: an analysis of perioperative risk factors. Chinese Journal of Traumatology. 2011;14(6):323–328.

Single-Factor Analysis for Postoperative Transfer to the ICU

FactorICU Group (N=89)Control Group (N=213)tChi-squareP
Preoperative
  Age ≥80 y, No.64 (71.91%)98 (46.01%)16.9339.000
  Sex, No.
    Male22671.3704.242
    Female67146
  Body mass index, mean±SD, kg/m223.52±4.7722.94±3.63−1.1496.251
  ASA classification, No.
    II1911627.8414.000
    III + IV7097
  Admission (emergency), No.19 (21.35%)20 (9.39%)7.9822.005
  Preexisting diabetes mellitus, No.21 (23.60%)48 (22.54%)0.0400.841
  Preexisting pulmonary diseases, No.66 (74.16%)60 (28.17%)54.5994.000
  Preexisting cardiovascular diseases, No.40 (44.94%)64 (30.05%)6.1698.013
  Preexisting cerebrovascular disease with functional impairment, No.19 (21.35%)14 (6.57%)14.0798.000
Perioperative
  Anesthesia, No.
    General6510713.3087.000
    Local24106
  Operative time >120 min, No.22 (24.72%)35 (16.43%)2.8155.093
  Blood loss, mean±SD, mL248.09±278.99190.31±272.47−1.6684.096
  Blood transfusion, No.52 (58.43%)104 (48.83%)2.3169.128
  Total infusion volume, mean±SD, mL1700.67±916.971497.47±677.92−2.1298.034
  Intraoperative hemoglobin <8 g/dL, No.57 (64.04%)9 (4.23%)131.5248.000
  Intraoperative lactic acid >2 mmol/L, No.75 (84.27%)31 (14.55%)133.9293.000

Risk Factors for Postoperative Transfer to the ICU

Risk FactorOdds Ratio95% Confidence IntervalZPWeighted Odds Ratio (Total=9)
Age ≥80 y5.831.779–19.0792.91.0041
ASA classification >II2.971.075–8.1952.10.0361
Anesthesia (general)3.871.246–12.0442.34.0191
Preexisting pulmonary diseases8.603.069–24.1124.09.0001
Intraoperative lactic acid 2 mmol/L17.986.807–47.4935.83.0002
Intraoperative hemoglobin <8 g/dL38.1610.372–140.3915.48.0003

Comparison of Outcomes Between the ICU Group and the Control Group (302 Patients)

OutcomeICU Group (N=89)Control Group (N=213)tChi-squareP
Pulmonary infection, No.13 (14.61%)19 (8.92%).0000
Hepatic function impairment (bilirubin ≥2.5 mg/dL), No.8 (8.99%)19 (8.92%)0.0004.9848
Renal function impairment (creatinine ≥2 mg/dL), No.10 (11.24%)32 (15.02%)0.7521.3858
Disturbance of blood coagulation, No.3 (3.37%)11 (5.16%)0.1411.7072
Hospital stay, mean±SD, d13.06±2.6713.28±3.08−0.588.5571
Medical cost, mean±SD, ¥10,00010.88±4.888.42±4.764.064.0001
Mortality, No.14 (15.73%)031.6662.0000

Comparison of Outcomes Between the ICU Group and the Control Group (205 Patients)

OutcomeICU Group (N=40)Control Group (N=165)tChi-squareP
Pulmonary infection, No.10 (25.00%)12 (7.27%)10.5611.0012
Hepatic function impairment (bilirubin ≥2.5 mg/dL), No.4 (10.00%)15 (9.09%)0.0316.8588
Renal function impairment (creatinine ≥2 mg/dL), No.6 (15.00%)20 (12.12%)0.2409.6235
Disturbance of blood coagulation, No.2 (5.00%)6 (3.64%)0.1596.6895
Hospital stay, mean±SD, d12.87±2.9412.98±2.90−0.215.8303
Medical cost, mean±SD, ¥10,00012.90±7.398.93±5.163.982.0001
Mortality, No.8 (16.67%)034.3401.0000

Comparison of Outcomes Between the Non-RSI Group and the RSI Group Among ICU Patients

OutcomeNon-RSI Group (N=89)RSI Group (N=40)tChi-squareP
Pulmonary infection, No.13 (14.61%)10 (25.00%)2.0347.1537
Hepatic function impairment (bilirubin ≥2.5 mg/dL), No.8 (8.99%)4 (10.00%)0.0210.8849
Renal function impairment (creatinine ≥2 mg/dL), No.10 (11.24%)6 (15.00%)0.0968.7557
Disturbance of blood coagulation, No.3 (3.37%)2 (5.00%)0.4665.4946
Hospital stay, mean±SD, d13.06±2.6712.87±2.940.362.7178
Medical cost, mean±SD, ¥10,00010.88±4.8812.90±7.39−1.840.0682
Mortality, No.14 (15.73%)8 (16.67%)0.3556.5509

Comparison of Outcomes Between the Non-RSI Group and the RSI Group

OutcomeNon-RSI Group (N=302)RSI Group (N=205)tChi-squareP
Postoperative transfer to ICU, No.89 (29.47%)40 (19.51%)6.3831.0115
Unplanned transfer to ICU, No.8 (2.65%)03.9436.0470
Pulmonary infection, No.32 (10.60%)22 (9.52%)0.0024.9612
Hepatic function impairment (bilirubin ≥2.5 mg/dL), No.27 (8.94%)19 (9.27%)0.0159.8996
Renal function impairment (creatinine ≥2 mg/dL), No.42 (13.91%)26 (12.68%)0.1576.6914
Disturbance of blood coagulation, No.14 (4.86%)8 (3.90%)0.1582.6908
Hospital stay, mean±SD, d13.21±2.9612.97±2.910.902.3674
Medical cost, mean±SD, ¥10,0009.15±4.928.93±5.150.485.6280
Mortality, No.14 (4.38%)8 (3.90%)0.1582.6908
Authors

The authors are from the Department of Anesthesiology (ZG, YW), Peking University Shougang Hospital, Shijingshan District; and the Anesthesia and Operation Center (ZG, FZ), The First Medical Center, the Medical School of Chinese PLA (FZ), and the Department of Anesthesiology (XW), The Fourth Medical Center, Chinese PLA General Hospital, Haidian District, Beijing, China.

Drs Guo and Zhao contributed equally to this work and should be considered as equal first authors.

The authors have no relevant financial relationships to disclose.

The authors thank their supervisor, Professor Liu, for guidance in every stage of the writing process.

Correspondence should be addressed to: Zhenggang Guo, MD, Department of Anesthesiology, Peking University Shougang Hospital, 9 Jinyuan Zhuang Rd, Shijingshan District, Beijing 100144, China ( gsgzg304@163.com).

Received: October 15, 2018
Accepted: February 14, 2019
Posted Online: January 31, 2020

10.3928/01477447-20200129-02

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