Lin et al. BMC Pediatrics(2024) 24:510
https://doi.org/10.1186/s12887-024-04989-4

BMC Pediatrics

RESEARCH

Open Access

Nomogram for intraoperatively acquiredpressure injuries in children undergoingcardiac surgery with cardiopulmonary bypass:a retrospective study
He Lin1, Haiyan Chen1, Jiehui Wang1 and Xiangai Ma1*
Abstract
Background We aimed to develop and validate a nomogram for predicting the risk of intraoperatively acquiredpressure injuries (IAPIs) in children undergoing cardiac surgery with cardiopulmonary bypass (CPB).
Methods This study retrospectively included 208 children aged 21 days to 8 years who underwent cardiac surgery
with CPB in a tertiary hospital in China between January 2020 and October 2023. All patients’ data were collectedfrom the hospital’s medical record system and randomly divided into the training (n = 146) and validation (n = 62)
cohorts by a ratio of 7:3. Logistic regression analysis was conducted in the training cohort to identify independentrisk factors and establish the nomogram. Finally, calibration curves, receiver operating characteristic (ROC) curves, anddecision curve analysis (DCA) were performed in both cohorts to validate the predictive ability of the nomogram.
Results 43 (14.7%) children developed IAPIs. Multivariate analysis showed that low Braden Q scores, use of steroids,
skin abnormalities, and low intraoperative SpO2 were independent risk factors for IAPIs. A nomogram integrating the 4
factors was established. The areas under the curve (AUCs) of the nomogram were 0.836 and 0.903 in the training andvalidation cohorts, respectively. Furthermore, calibration curves and DCA demonstrated good calibration and clinicalapplicability of the nomogram.
Conclusion We constructed a reliable nomogram based on specific risk factors for children undergoing cardiac
surgery with CPB, which could be used as an effective and convenient tool for prevention of IAPIs.
Keywords Cardiac surgery, Cardiopulmonary bypass, Intraoperatively acquired pressure injury, Risk factors,
Nomogram*Correspondence:
Xiangai Ma
Pcnl@163.com
1
Department of Operating Room, The Second Affiliated Hospital andYuying Children’s Hospital of Wenzhou Medical University,
Wenzhou 325000, Zhejiang, China© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0
International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you
give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified thelicensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images orother third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to thematerial. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation
or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://
creativecommons.org/licenses/by-nc-nd/4.0/.

Lin et al. BMC Pediatrics(2024) 24:510

Introduction
Intraoperatively acquired pressure injuries (IAPIs) referto the skin and subcutaneous tissue damage caused byprolonged pressure and shear during surgery, typicallylocated at the bony prominence or at interfaces withmedical devices/equipment [1]. In addition to causing
pain and negative impacts on body image, IAPIs canlead to infection, reoperation, extended hospitalization, increased treatment costs, and decreased quality oflife for patients [2–4]. According to the report from the
National Pressure Ulcer Advisory Panel (NPUAP) in the
United States, IAPIs accounted for 45% of health careassociated pressure injuries, posing additional risks andharm to surgical patients [5]. Importantly, IAPIs are recognized as serious, costly, but preventable medical problems, and the identification of high-risk individuals andrisk factors for IAPIs is the first step in preventing IAPIs.
A recent systematic review showed that cardiac surgery patients were among the most susceptible populations to pressure injuries [6]. Compared to other surgicalprocedures, cardiac surgery exhibits certain characteristics that may contribute to IAPIs, such as prolonged timeon the operating table, additional external forces during
thoracotomy, as well as the perfusion impairment andhypothermia induced by cardiopulmonary bypass (CPB)[7, 8]. It has been reported that the incidence of hospitalacquired pressure injuries in pediatric patients with congenital heart disease ranges from 9.7 to 15.6% [9, 10]. The
occurrence of pressure injuries not only causes physicaland psychological pain to pediatric patients, but also
increases the risk of complications, significantly hindering their postoperative recovery.
The literature on the occurrence and risk factors forpressure injuries in cardiac surgery patients mainly
focuses on adult populations. Little is known about thedevelopment of pressure injuries in pediatric cardiac
surgery patients. These young patients may be susceptible to similar risk factors as their adult counterparts,
such as prolonged immobility during complex surgical procedures [11]. However, due to unique anatomical and physiological characteristics, children exhibit
certain differences in the occurrence and risk factors ofpressure injuries compared to adults. For example, thebrain weight of a newborn is approximately 25% of thatin adulthood, while the body weight is only around 5% of
adult weight. This leads to a higher incidence of occipital pressure injuries in infants, whereas common pressure injury sites in adults include the sacrum, buttocks,
and heels [12]. Moreover, some health-related factors of
IAPIs development in adults, such as smoking and diabetes, were relatively rare in pediatric patients [13, 14].
In the update of the Prevention and Treatment of Pressure Ulcers: Clinical Practice Guideline 2019 (referred
to as Guideline 2019), it was recommended that risk

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assessment of pressure injury should encompass surgeryrelated factors and specific factors for children [15]. Thissuggested that adequate attention should be given to theidentification and management of risk factors for pressure injury in the pediatric surgical populations. Currently, there is no valid predictive tool for the risk of
IAPIs in pediatric surgical populations, especially in children undergoing cardiac surgery, making accurate risk
assessment of IAPIs in these patients relatively challenging. Common pediatric pressure injury scales, such as theBraden Q scale [16] and the Norton scale [17], evaluate
relatively few intraoperative factors and lack predictive
validity for IAPIs. Relevant research is of great importance, but existing evidence is limited [18]. Accurate literature searches revealed only a few articles reporting
the incidence and influencing factors of pressure injuries
in children undergoing cardiac surgery; however, thesestudies focused on hospital-acquired pressure injuries
rather than IAPIs [9, 10]. No studies have yet developed
a risk prediction model for IAPIs in pediatric cardiac
surgery.
To address this issue, we developed and validated anomogram by retrospectively investigating the specificrisk factors for IAPIs in children undergoing cardiac
surgery with CPB, with the aim of providing theoretical guidance for clinical preventive interventions in thisgroup.

Methods
Study design

This was a retrospective cohort study.
Setting

All surgeries for patients of this study were performedin the operating room of the Second Affiliated Hospitaland Yuying Children’s Hospital of Wenzhou Medical University. Data collection took place from October 2023 to
December 2023 in our cardiothoracic surgery unit andoperating room.
Participants

The study subjects were children who underwent cardiac surgery with CPB in the operating room of a tertiary hospital in China from January 2020 to October
2023. Inclusion criteria: (1) aged between 21 days and 8
years (recommended age range for use of the Braden Q
scale [19, 20]); (2) underwent cardiac surgery with CPB.
Exclusion criteria: (1) pressure injuries occurred before
surgery; (2) presence of skin disease affecting the observation of IAPIs; (3) intraoperative death (no skin observation record for patients who died intraoperatively); (4)postoperative installation of extracorporeal membrane
oxygenation (ECMO) (no skin observation record forLin et al. BMC Pediatrics(2024) 24:510

this group of patients due to restricted mobility); (5) data
missing.
Variables

Based on literature, guidelines, and clinical experience, a
total of 18 potential risk factors were included: (1) Demographic: sex, age, and weight. (2) Preoperative factors:
serum albumin, hemoglobin, use of steroids, condition ofskin, the Braden Q scores, and the grade of the American Society of Anesthesiologists (ASA) physical statusclassification system. (3) Intraoperative factors: durationof surgery, duration of CPB, operative position, intraoperative blood loss, intraoperative urine output, minimum
oxygen saturation (SpO2), minimum temperature, anduse of heating blankets. The primary outcome variable
was the diagnosis of IAPIs, and the remainder included
the stages and sites of pressure injuries, as well as duration of hospitalization.
The diagnostic criteria for IAPIs were adopted fromthe definition of IAPIs in the Prevention and Treatmentof Pressure Ulcers: Clinical Practice Guideline 2019[1]. According to the National Pressure Ulcer Expert
Advisory Panel (NPUAP) Pressure Injury Staging System, IAPIs were classified as stages 1 to 4, unstageable,
and deep tissue pressure injury (refer to Supplementary
Material 1). The preoperative Braden Q scores wereassessed on admission. This scale ranges from 7 to 28,
with lower scores indicating higher risk for pressure injuries [20]. The definitions and rationale for inclusion of theremaining variables are detailed in Supplementary Material 2.
Data sources

Data were collected from the hospital’s electronic medical record system. To maintain consistency in the resultsof the review, two trained researchers were assigned tocollect the data, and another researcher was responsible
for checking the accuracy of the data.
Study size

According to the Kendall’s theory, the sample size isapproximately 10 times the number of variables [21].
Considering a 10% sample loss rate, we estimated thatabout (18 × 10 ÷ 0.9=) 200 samples were needed. Since
there were about 60–90 pediatric cardiac surgeries with
CPB per year in our hospital, we collected 4-year clinicaldata. Finally, a total of 43 cases of IAPIs occurred in 208
patients. And 4 predictors of IAPIs were included in themultivariable Logistic regression. The number of events
per predictor variable (EPV) was (43/4≈) 11, meetingthe criterion of 10–20 EPV proposed by Harrell and colleagues [22, 23].

Page 3 of 10

Statistical methods

The data was randomly divided into training and validation cohorts in a ratio of 7:3 [24]. Non-normally distributed continuous variables and categorical variables
were represented by the median (interquartile ranges)
and number (proportion), respectively. The differences
between variables were compared using Mann-Whitney
U tests and chi-square tests by SPSS 27.0. Multivariate
Logistic regression analysis was conducted for variables
with P-value < 0.1 in univariate analysis to identify independent risk factors for IAPIs. Based on the results ofthe multivariate analysis, a nomogram was constructedusing the “ggplot2” package in R 4.3.2 software. Finally,
calibration curves, receiver operating characteristic(ROC) curves, and decision curve analysis (DCA) were
performed in both cohorts to validate the predictive ability and clinical utility of the nomogram. A P-value < 0.05
was defined as statistically significant.
Ethical considerations

This study was approved by the Ethics Committee of theSecond Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University [2024-K-054-01]. Dueto the retrospective nature of this study, the informed
consent of patients was waived by the Ethics Committeeof the Second Affiliated Hospital and Yuying Children’s
Hospital of Wenzhou Medical University according to
the national regulations [25]. The procedures of thisresearch adhered to the Declaration of Helsinki.

Results
Participants

A total of 208 eligible patients were included in the study[median age: 12 (5, 48) months; male: 112 (53.8%)], of
which 43 developed IAPIs, with an incidence of 20.7%.
The patient enrollment process was shown in Fig. 1. The
208 patients were divided into training and validation
cohorts in a ratio of 7:3, and there were no significant differences in variables between the two cohorts (Table 1).
Table 2 demonstrated the characteristics of patients’
IAPIs. As can be seen, the majority of patients (91.1%)
with IAPIs were at stage 1 and the most common siteof pressure injury was the occipital (22.2%), followed by
the sacrococcygeal (18.5%) and ankle/heel (18.5%). No
medical device-related pressure injuries occurred during
surgery.
Risk factors analysis

We performed univariate analysis in the training cohort,which showed P-value less than 0.1 for 4 variables(Table 3): use of steroids (P = 0.075), skin abnormalities(P = 0.019), Braden Q scores (P = 0.002), and intraoperative SpO2 (P<0.001). The 4 variables were then integrated into the multivariate Logistic regression analysis.

Lin et al. BMC Pediatrics(2024) 24:510

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Fig. 1 Patient enrollment process

The results revealed that use of steroids (odds ratio [OR],3.113; 95% confidence interval [CI], 1.113–8.807) andskin abnormalities (OR, 3.266; 95%CI, 1.062–10.044)
were independent risk factors for IAPIs, whereas highBraden Q scores (OR, 0.672; 95%CI, 0.476–0.948) andintraoperative SpO2 (OR, 0.882; 95%CI, 0.825–0.943)
were independent protective factors for IAPIs (Table 4).

that the nomogram possesses clinical utility at a specificthreshold. We observed that the net benefit of applying
the nomogram was significantly higher than “All” and“None” over a wide range of the threshold probability of
IAPIs occurrence, suggesting good clinical applicabilityof the nomogram (the area between the two dotted lines
in the Fig. 3C and F).

Development and validation of the nomogram

Discussion
The present study developed the first nomogram for predicting the risk of IAPIs in children undergoing cardiac
surgery with CPB by retrospectively analyzing their clinical data. Among several potential factors for IAPIs, wefinally screened 4 independent risk factors to construct
a nomogram for predicting the risk of developing IAPIs.
ROC curves and calibration curves demonstrated thenomogram’s good accuracy and calibration. DCA indicated that the nomogram possesses excellent clinicalapplicability.
This study showed that Braden Q score was an important predictive factors of IAPIs. The Braden Q scale,
adapted from the Braden scale by Quigley and Curleyin 1996, was the most commonly used scale for assessing pressure injury risk in pediatrics [26, 27]. Although
recent studies have noted that the Braden Q scale hasmoderate predictive accuracy and that there is a needfor further modification or development of new tools, itremains the more reliable pressure injury assessment tool
available [28, 29]. In this study, Braden Q scores demonstrated a significant association with IAPIs (P < 0.01). We
believed that the nomogram model, which combines specific perioperative risk factors on the basis of the Braden
Q scores, can effectively improve the predictive validityof IAPIs.

Based on the 4 risk predictors, we developed a nomogram predicting the probability for IAPIs in children
undergoing cardiac surgery with CPB (Fig. 2). To better
illustrate the usage of the nomogram, we have annotatedthe characteristics of a patient within the nomogram. As
depicted in Fig. 2, the patient had a Braden Q score of 24,
an SpO2 level of 80%, and exhibited neither skin abnormalities nor steroid use. The points associated with thefour variables are 36.3, 57.5, 0, and 0, respectively. Therefore, the patient’s total point is approximately 94, whichcorresponds to a 65% risk probability for developing
IAPIs.
Subsequently, we tested the prediction performance of
nomogram in both training and validation cohorts. The
areas under the curve (AUCs) of the nomogram were
0.836 (95%CI: 0.764–0.907) and 0.903 (95%CI: 0.824–
0.982) in the training and validation cohorts, demonstrating a relatively good predictive accuracy (Fig. 3A
and D). Furthermore, calibration curves demonstrated
good consistency between predicted probabilities andactual probabilities (Fig. 3B and E). In DCA, the horizontal line represents that none of the patients received
clinical pressure injury intervention, whereas the otheroblique line represents that all of the patients received
clinical intervention. When the net benefit of the nomogram exceeds that of the two extreme curves, it indicatesLin et al. BMC Pediatrics(2024) 24:510

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Table 1 Demographics and clinical characteristics of the patients (n = 208)
Variables
Demographics features
Sex
Male
FemaleAge (months)
Weight (Kg)
Preoperative factors
Serum albumin (g/L)
Hemoglobin (g/L)
AnemiaNon-anemia
Use of steroids
Yes
No
ASA classification
III-IV
I-II
Skin abnormalities
Yes
No
Braden Q scores
Intraoperative factors
Duration of surgery (h)
≥6 h
<6 h
Duration of CPB (min)≥ 100 min< 100 minOperative position
Lateral position
Supine position
Intraoperative blood loss (mL)Intraoperative urine output (mL)
Minimum SpO2 (%)
< 90%
≥ 90%
Minimum temperature (℃)
Use of heating blanket
YesNo
Outcomes
Presence of IAPIs
Yes
No
Duration of hospitalization

Total/Range

Training cohort (n = 146)

Validation cohort (n = 62)

P-value112 (53.8%)
96 (46.2%)
0.8–96.0
2.7–37.0

77 (52.7%)
69 (47.3%)
12.0 (5.0, 48.0)
9.1 (6.0, 14.0)

35 (56.5%)
27 (43.5%)
12.0 (5.0, 48.0)
9.1 (6.0, 13.5)

0.623

30.7–53.1
91.0-171.0
67 (32.2%)
141 (67.8%)

44.4 (42.3, 46.3)
115.0 (105.8, 122.3)
45 (30.8%)101 (69.2%)

45.0 (42.3, 46.5)
113.0 (102.8, 123.3)
22 (35.5%)
40 (64.5%)

0.560

54 (26.0%)
154 (74.0%)

38 (26.0%)
108 (74.0%)

16 (25.8%)
46 (74.2%)

0.973

85 (40.9%)
123 (59.1%)

58 (39.7%)
88 (60.3%)

27 (43.5%)
35 (56.5%)

0.608

35 (16.8%)
173 (83.2%)
18.0–28.0

25 (17.1%)
121 (82.9%)
28.0 (27.0, 28.0)

10 (16.1%)
52 (83.9%)
28.0 (27.0, 28.0)

0.861

3.0-8.640 (19.2%)
168 (80.8%)
36–28782 (39.4%)
126 (60.6%)

4.6 (4.0, 5.2)
26 (17.8%)
120 (82.2%)
90.5 (73.5, 123.0)
54 (37.0%)
92 (63.0%)

4.8 (4.4, 5.5)
14 (22.6%)
48 (77.4%)
94.5 (73.5, 135.3)
28 (45.2%)
34 (54.8%)

0.075
0.424

23 (11.1%)
185 (88.9%)
10.0–80.0
10.0-800.0
67.0-100.0
49 (23.6%)
159 (76.4%)
24.9–37.0

17 (11.6%)
129 (88.4%)
20.0 (20.0, 25.0)
150.0 (86.3, 300.0)
96.0 (92.0, 99.0)
32 (21.9%)
114 (78.1%)
33.7 (32.3, 34.5)

6 (9.7%)56 (90.3%)
20.0 (20.0, 21.3)
135.0 (70.0, 280.0)
95.5 (88.0, 98.3)
17 (27.4%)
45 (72.6%)
33.0 (32.0, 34.3)

0.798

21 (10.1%)
187 (89.9%)

14 (9.6%)
132 (90.4%)

7 (11.3%)
55 (88.7%)

0.710

43 (20.7%)
165 (79.3%)
10.0-121.0

28 (19.2%)
118 (80.8%)
20.0 (14.0, 35.0)

15 (24.2%)
47 (75.8%)
21.0 (14.0, 36.3)

0.414

0.779
0.888

0.510

0.972

0.335
0.270

0.908
0.249
0.378
0.392
0.308

0.624

Abbreviations: CPB, cardiopulmonary bypass; IAPIs, intraoperatively acquired pressure injuries

Consistent with the findings of Shields and Lu et al.
[30–32], the incidence of IAPIs was higher in patientsusing steroids. Reduction of growth factors induced bysteroids may be an important factor in their promotionof pressure injury development [33]. Skin abnormalities,
such as moisture, dryness, and edema, can weaken theskin’s barrier function and also contribute to pressure
injury [34]. Compared to adults, children have a thinnerand functionally immature epidermal layer, which carries a high risk for excess water loss and a higher permeability to chemicals, making them more susceptible
to skin abnormalities [35]. Therefore, it’s recommended

Lin et al. BMC Pediatrics(2024) 24:510

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Table 2 Characteristics of patients’ IAPIs (n = 43 a)n%Stage 1
Stage 2
Stage 3 and over

51
5
0

91.1%
8.9%
0

Occipital
Sacrococcygeal
Ankle/heel
Elbow joint
Mid-axillary line
Left temporal/Iliac crest
Buttocks
Back

13
11
11
6
5
4
3
3

22.2%
18.5%
18.5%
11.1%
9.3%
9.3%
5.6%
5.6%

Stage of IAPIs

Site of IAPIs

Abbreviations: IAPIs, intraoperatively acquired pressure injuriesa

The total number of wounds was greater than 43 due to the fact that somepatients had multiple pressure injuries

to provide more meticulous skin care for this surgical group, including utilizing skin barrier products andhighly absorbent incontinence products [1].
Low intraoperative oxygen saturation was the most significant factor in this study. The principle of low oxygen
saturation leading to IAPIs was mainly due to hypoxia
causing tissue cell damage along with reduced tissue tolerance to pressure and shear [36]. The Guideline 2019
also highlighted specific risk factors to consider whenassessing PI risk in pediatric patients, such as oxygen
saturation, hemoglobin levels, and other indicators ofoxygenation status [1]. Kulik et al. [37] proved that SpO2
below 85% was a predictor of the occurrence of hospitalacquired pressure injuries in children with congenital
heart disease. This study further supported that intraoperative SpO2 was significantly associated with the development of IAPIs in children undergoing cardiac surgery.
In previous studies, Gao et al. found that length ofoperation ≥ 6 h (β = 2.66, OR = 14.30) and intraoperative
blood loss (β = 0.67, OR = 1.95) were the risk factors for
IAPIs in pediatric patients [38]. Other studies exhibitedthat the age of pediatric population was inversely related
to the risk for pressure injury, which is the opposite ofadults [39, 40]. In our study, variables such as age, lengthof surgery, and intraoperative blood loss were not significant factors affecting IAPIs. This inconsistency may becaused by differences in study populations. Besides, theeffect of procedure duration and CPB duration on IAPIs
remained controversial. Chen et al. [41] found that CPB
duration was an independent influencing factor on theoccurrence of IAPIs in patients undergoing cardiovascular surgery (both adults and children; P < 0.001). However, a study of 286 adult patients undergoing cardiac
surgery by Shen et al. [42] emphasized that the durationof surgery, instead of CPB, was a risk factor for IAPIs.

These controversies still need more in-depth research to
be resolved.
Nomograms were commonly used clinical prediction
models with the advantages of convenience and ease ofuse [43]. The nomogram we constructed had reliable predictive performance in cross-validation. Through thistool, clinical nurses were able to predict the probability of IAPIs in pediatric patients before cardiac surgery,screen patients at high risk of IAPIs, and take preventive
measures in advance. The nomogram also suggested thatmeasures such as ensuring that the skin is not excessively moist or dry and maintaining normal intraoperative SpO2 levels can play a positive role in preventing thedevelopment of IAPIs. Additionally, for children requiring medications to prevent postoperative complicationsof CPB, the use of steroids may be unavoidable. Operating room nurses may consider applying gel pads or dressings intraoperatively for such high-risk patients to reducethe incidence of IAPIs.
Limitations

This retrospective study still had some limitations. Firstly,
the study population was relatively small, and the number of included variables were limited. Therefore, further
studies should be conducted in high-volume centers toinvestigate more potential risk factors, such as nutritional status and medical device factors. Secondly, inthis model, the variable SpO2 was the minimum value
recorded during surgery. While this value effectively represents the patient’s worst oxygen saturation state, it does
not account for the duration of hypoxemia. In addition,
we selected the patients with complete medical records,
which may have resulted in some selection bias. Hence,
our findings require validation through prospective studies in the future.

Conclusion
Independent risk factors for IAPIs in children undergoing cardiac surgery with CPB included low Braden Q
scores, use of steroids, skin abnormalities, and low intraoperative SpO2. The nomogram based on these 4 factors exhibited good predictive performance and clinicalapplicability. It can serve as an effective and convenient
tool to assist nurses in early identification of high-riskpatients for IAPIs and making informed clinical decisions, thereby reducing the risk of IAPI occurrence andimproving patient outcomes.

Lin et al. BMC Pediatrics(2024) 24:510

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Table 3 Univariate analysis of IAPIs in the training cohort
Variables
Demographics features
Sex
Male
FemaleAge (months)
Weight (Kg)
Preoperative factors
Serum albumin (g/L)
Hemoglobin (g/L)
AnemiaNon-anemia
Use of steroids
Yes
No
ASA classification
III-IV
I-II
Skin abnormalities
Yes
No
Braden Q scores
Intraoperative factors
Duration of surgery (h)
≥6 h
<6 h
Duration of CPB (min)≥ 100 min< 100 minOperative position
Lateral position
Supine position
Intraoperative blood loss (mL)Intraoperative urine output (mL)
Minimum SpO2 (%)
< 90%
≥ 90%
Minimum temperature (℃)
Use of heating blanket
YesNo
Outcomes
Duration of hospitalization

Total/Range (n = 146)

IAPIs group (n = 28)

Non-IAPIs group (n = 118)

P-value

77 (52.7%)
69 (47.3%)
12.0 (5.0, 48.0)
9.1 (6.0, 14.0)

15 (53.6%)
13 (46.4%)
7.0 (2.3, 42.0)
7.4 (4.7, 16.5)

62 (52.5%)
56 (47.5%)
12.0 (5.8, 48.0)
9.5 (6.2, 14.0)

0.922

44.4 (42.3, 46.3)
115.0 (105.8, 122.3)
45 (30.8%)101 (69.2%)

44.5 (40.4, 46.9)
121.5 (109.3, 128.8)
8 (28.6%)
20 (71.4%)

44.3 (42.6, 46.2)
114 (105.0, 119.3)
37 (31.4%)
81 (68.6%)

0.809

38 (26.0%)
108 (74.0%)

11 (39.3%)
17 (60.7%)

27 (22.9%)
91 (77.1%)

0.075

59 (39.7%)
88 (60.3%)

10 (35.7%)
18 (64.3%)

48 (40.7%)
70 (59.3%)

0.629

25 (17.1%)
121 (82.9%)
28.0 (27.0, 28.0)

9 (32.1%)
19 (67.9%)
27.0 (25.3, 28.0)

16 (13.6%)
102 (86.4%)
28.0 (27.0, 28.0)

0.019

4.6 (4.0, 5.3)
26 (17.8%)
120 (82.2%)
90.5 (73.5, 123)
54 (37.0%)
92 (63.0%)

4.8 (4.1, 6.5)
8 (28.6%)
20 (71.4%)
91.0 (75.3, 142.8)
12 (42.9%)
16 (57.1%)

4.6 (4.0, 5.1)
18 (15.3%)
100 (84.7%)
90.0 (72.0, 107.0)
42 (35.6%)
76 (64.4%)

0.241
0.098

17 (11.6%)
129 (88.4%)
20.0 (20.0, 25.0)
150.0 (86.3, 300.0)
96.0 (92.0, 99.0)
32 (21.9%)
114 (78.1%)
33.7 (32.3, 34.5)

5 (17.9%)23 (82.1%)
20.0 (20.0, 20.0)
145.0 (77.5, 350.0)
90.5 (81.8, 96.0)
14 (50.0%)
14 (50.0%)
33.9 (31.9, 34.7)

12 (10.2%)
106 (89.8%)
20.0 (20.0, 30.0)
150.0 (100.0, 300.0)
97.0 (93.0, 100.0)
18 (15.3%)
100 (84.7%)
33.6 (32.4, 34.5)

0.254

14 (9.6%)
24 (85.7%)

4 (14.3%)
24 (85.7%)

10 (8.5%)
108 (91.5%)

0.348

20.0 (14.0, 35.0)

27.5 (13.8, 43.8)

19.0 (14.0, 33.3)

0.075

OR
0.672
3.266
3.113
0.882

95%CI
0.476–0.948
1.062–10.044
1.113–8.807
0.825–0.943

0.147
0.419

0.774

0.002

0.301
0.474

0.497
0.746
<0.001<0.0010.879

Abbreviations: IAPIs, intraoperatively acquired pressure injuries; CPB, cardiopulmonary bypass

Table 4 Multivariate Logistic regression analysis of IAPIs in the training cohort
Variables
Braden Q scores
Skin abnormalities
Use of steroids
Minimum SpO2

B
-0.3981.148
1.135-0.126

SE
0.176
0.573
0.525
0.034

Abbreviations: IAPIs, intraoperatively acquired pressure injuries

Wald
5.134
4.266
4.680
13.557

P
0.023
0.039
0.031
<0.001

Lin et al. BMC Pediatrics(2024) 24:510

Page 8 of 10

Fig. 2 Nomogram predicting the probability for IAPIs in children undergoing cardiac surgery with cardiopulmonary bypass

Fig. 3 Validation of the nomogram. Training cohort: (A) ROC curves of the nomogram for predicting IAPIs; (B) Calibration curve of the nomogram; (C)Decision curve analysis of the nomogram. Validation cohort: (D) ROC curves of the nomogram for predicting IAPIs; (E) Calibration curve of the nomogram;(F) Decision curve analysis of the nomogram

Supplementary Information

The online version contains supplementary material available at https://doi.
org/10.1186/s12887-024-04989-4.
Supplementary Material 1
Supplementary Material 2

Acknowledgements
Not applicable.
Author contributions
XM and HL conceived and designed the study. HC, JW and XM collected thedata. HL and HC analyzed and interpreted the data. All authors were involvedin drafting and revising the paper. All authors read and approved the final
manuscript.

Lin et al. BMC Pediatrics(2024) 24:510

Funding
This study was funded by the Project of Wenzhou Science and Technology
Bureau (Y2023594, Y20240974).
Data availability
The datasets generated and/or analysed during the current study are notpublicly available due to patient privacy concerns but are available from thecorresponding author on reasonable request.

Declarations
Ethics approval and consent to participate
This study was approved by the Ethics Committee of the Second AffiliatedHospital and Yuying Children’s Hospital of Wenzhou Medical University [2024K-054-01]. Due to the retrospective nature of this study, the informed consent
of patients was waived by the Ethics Committee of the Second AffiliatedHospital and Yuying Children’s Hospital of Wenzhou Medical University
according to the national regulations [25]. The procedures of this researchadhered to the Declaration of Helsinki.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Received: 26 February 2024 / Accepted: 1 August 2024

References
1. Prevention. and treatment of pressure ulcers/injuries: clinical practice guideline. [Internet]. 2019 [Oct. 6]. https://www.epuap.org/pu-guidelines/
2. Fred C, Ford S, Wagner D, Vanbrackle L. Intraoperatively acquired pressure
ulcers and perioperative normothermia: a look at relationships. AORN J.
2012;96(3):251–60.
3. Chen H, Ren G, Guo X, Yang T. Construction and validation of a management
model for intraoperatively acquired pressure injury based on PISETI theory.
Asian J Surg. 2023;46(7):2763–4.
4. Ueno T, Kabata T, Kajino Y, Inoue D, et al. Risk factors for pressure ulcers fromthe use of a pelvic positioner in hip surgery: a retrospective observational
cohort study in 229 patients. Patient Saf Surg. 2020;14:10.
5. Engels D, Austin M, McNichol L, Fencl J, Gupta S, Kazi H. Pressure
ulcers: factors contributing to their development in the OR. AORN J.
2016;103(3):271–81.
6. Rao AD, Preston AM, Strauss R, Stamm R, Zalman DC. Risk factors Associated with pressure ulcer formation in critically ill cardiac surgery patients: asystematic review. J Wound Ostomy Cont Nurs. 2016;43(3):242–7.
7. Cai JY, Zha ML, Song YP, Chen HL. Predicting the development of surgeryrelated pressure Injury using a machine learning Algorithm Model. J Nurs Res.
2020;29(1):e135.
8. Steinmetz JA, Langemo DK. Changes in occipital capillary perfusionpressures during coronary artery bypass graft surgery. Adv Wound Care.
1996;9(3):28–32.
9. Kulik LA, Hasbani NR, Stellar JJ, Quigley SM, Shelley SS, Wypij D, Curley
MAQ. Hospital-acquired pressure injuries in children with congenital
heart disease: prevalence and Associated factors. Pediatr Crit Care Med.
2019;20(11):1048–56.
10. Neidig JR, Kleiber C, Oppliger RA. Risk factors associated with pressure ulcers
in the pediatric patient following open–heart surgery. Prog Cardiovasc Nurs.
1989;4(3):99–106.
11. Kulik LA, Connor JA, Graham DA, Hickey PA. Pressure injury prevention for
paediatric cardiac surgical patients using a nurse-driven standardized clinicalassessment and management plan. Cardiol Young. 2018;28(9):1151–62.
12. Delmore B, Deppisch M, Sylvia C, Luna-Anderson C, Nie AM. Pressure injuries
in the Pediatric Population: a national pressure Ulcer Advisory Panel White
Paper. Adv Skin Wound Care. 2019;32(9):394–408.
13. Wang I, Walker RM, Gillespie BM, Scott I, Sugathapala R, Chaboyer W. Risk
factors predicting hospital-acquired pressure injury in adult patients: an
overview of reviews. Int J Nurs Stud. 2024;150:104642.

Page 9 of 10

14. Gyawali D, Tharu NS. Pressure injury susceptibility related to lifestyle factors
in patients with spinal cord injury: a cross-sectional survey. J Wound Care.
2023;32(Sup4):S29–38.
15. Kottner J, Cuddigan J, Carville K, Balzer K, et al. Prevention and treatment ofpressure ulcers/injuries: the protocol for the second update of the international clinical practice Guideline 2019. J Tissue Viability. 2019;28(2):51–8.
16. He W, Liu P, Chen HL. The Braden Scale cannot be used alone for assessing
pressure ulcer risk in surgical patients: a meta-analysis. Ostomy Wound Manage. 2012;58(2):34–40.
17. Gurkan A, Kirtil I, Aydin YD, Kutuk G. Pressure injuries in surgical patients: acomparison of Norton, Braden and Waterlow risk assessment scales. J Wound
Care. 2022;31(2):170–7.
18. Chello C, Lusini M, Schilirò D, Greco SM, Barbato R, Nenna A. Pressure ulcers
in cardiac surgery: few clinical studies, difficult risk assessment, and profoundclinical implications. Int Wound J. 2019;16(1):9–12.
19. Speth J. Guidelines in practice: Prevention of Perioperative pressure Injury.
AORN J. 2023;118(1):37–44.
20. Curley MA, Razmus IS, Roberts KE, Wypij D. Predicting pressure ulcer risk inpediatric patients: the Braden Q Scale. Nurs Res. 2003;52(1):22–33.
21. Kendall MG, Stuart A, Ord JK, Arnold SF, O’Hagan A. Kendall’s advanced
theory of statistics, 6th edn; 1994.
22. Harrell FE Jr., Lee KL, Matchar DB, Reichert TA. Regression models for prognostic prediction: advantages, problems, and suggested solutions. Cancer Treat
Rep. 1985;69(10):1071–7.
23. Peduzzi P, Concato J, Kemper E, Holford TR, Feinstein AR. A simulation studyof the number of events per variable in logistic regression analysis. J Clin
Epidemiol. 1996;49(12):1373–9.
24. Zeng J, Li K, Cao F, Zheng Y. Development and validation of survival prediction model for gastric adenocarcinoma patients using deep learning: a SEERbased study. Front Oncol. 2023;13:1131859.
25. National Health Commission of the People’s Republic of China. Notice on
Issuing the Measures for Ethical Review of Life Sciences and Medical Research
Involving Human Subjects. [Internet]. 2023 [Jul. 25]. https://www.gov.cn/
zhengce/zhengceku/2023-02/28/content_5743658.htm
26. Quigley SM, Curley MA. Skin integrity in the pediatric population: preventing
and managing pressure ulcers. J Soc Pediatr Nurs. 1996;1(1):7–18.
27. Ferreira MKM, Gurgel SS, Lima FET, Cardoso M, Silva VMD. Instruments for thecare of pressure injury in pediatrics and hebiatrics: an integrative review ofthe literature. Rev Lat Am Enfermagem. 2018;26:e3034.
28. Liao Y, Gao G, Mo L. Predictive accuracy of the Braden Q Scale in risk
assessment for paediatric pressure ulcer: a meta-analysis. Int J Nurs Sci.
2018;5(4):419–26.
29. Chun X, Lin Y, Ma J, He J, Ye L, Yang H. Predictive efficacy of the Braden Q
Scale for pediatric pressure ulcer risk assessment in the PICU: a meta-analysis.
Pediatr Res. 2019;86(4):436–43.
30. Chen HL, Shen WQ, Xu YH, Zhang Q, Wu J. Perioperative corticosteroids
administration as a risk factor for pressure ulcers in cardiovascular surgicalpatients: a retrospective study. Int Wound J. 2015;12(5):581–5.
31. Shields A, Lin JI. Risk factors Associated with pressure Injury in critically Ill Children with congenital heart disease. Am J Crit Care. 2023;32(3):216–20.
32. Lu CX, Chen HL, Shen WQ, Feng LP. A new nomogram score for predicting
surgery-related pressure ulcers in cardiovascular surgical patients. Int Wound
J. 2017;14(1):226–32.
33. Yang JJ, Wang XL, Shi BW, Huang F. The angiogenic peptide vascular endothelial growth factor-basic fibroblast growth factor signaling is up-regulated
in a rat pressure ulcer model. Anat Rec (Hoboken). 2013;296(8):1161–8.
34. Sun ZW, Guo MR, Yang LZ, Chen ZJ, Zhang ZQ. Risk factor analysis and risk
prediction model construction of pressure Injury in critically ill patientswith Cancer: a retrospective cohort study in China. Med Sci Monit.
2020;26:e926669.
35. Schindler CA, Mikhailov TA, Cashin SE, Malin S, Christensen M, Winters JM.
Under pressure: preventing pressure ulcers in critically ill infants. J Spec
Pediatr Nurs. 2013;18(4):329–41.
36. Weng PW, Chang WP. Extrinsic factors of pressure injuries in patientsduring surgery: a frequency matched retrospective study. Int Wound J.
2023;20(6):1934–42.
37. Kulik LA, Hasbani NR, Stellar JJ, Quigley SM, Shelley SS, Wypij D, Curley MAQ,
for, Braden QDSG. Hospital-Acquired Pressure Injuries in Children With Congenital Heart Disease: Prevalence and Associated Factors. Pediatr Crit CareMed. 2019;20(11):1048–1056.

Lin et al. BMC Pediatrics(2024) 24:510

38. Gao L, Yang L, Li X, Chen J, Du J, Bai X, Yang X. The use of a logistic regression
model to develop a risk assessment of intraoperatively acquired pressure
ulcer. J Clin Nurs. 2018;27(15–16):2984–92.
39. Qu H, Tang X, Zeng W, Fu S, Zhou R, Mou S. Risk factors and the nomogram
model for intraoperatively acquired pressure injuries in children with brain
tumours: a retrospective study. Int Wound J. 2023;20(6):2250–9.
40. Weng PW, Lin YK, Seo JD, Chang WP. Relationship between predisposing andfacilitating factors: does it influence the risk of developing peri-operative
pressure injuries? Int Wound J. 2022;19(8):2082–91.
41. Chen X, Liao H, Gao W, Chen Y, Huang J, Wei Y. Cardiopulmonary bypass
duration and the Incidence of Pressure Injuries in patients undergoing
Cardiovascular surgery: a retrospective cohort study. J Wound Ostomy Cont
Nurs. 2020;47(4):343–8.

Page 10 of 10

42. Shen WQ, Chen HL, Xu YH, Zhang Q, Wu J. The relationship between lengthof surgery and the incidence of pressure ulcers in Cardiovascular Surgicalpatients: a retrospective study. Adv Skin Wound Care. 2015;28(10):444–50.
43. Ohori Tatsuo G, Riu Hamada M, Gondo T, Hamada R. [Nomogram as predictive model in clinical practice]. Gan Kagaku Ryoho. 2009;36(6):901–6.

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