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Heliyon
Heliyon
Heliyon
2405-8440
Elsevier

S2405-8440(24)13514-1
10.1016/j.heliyon.2024.e37483
e37483
Research Article
The modified exhaust method is used in open-heart surgery for cardiopulmonary bypass in children with congenital heart disease
Luo Hong-bo abd
Shi Kun b
Chen Hui-wen Chenhuiwen@scmc.com.cn
abc⁎
a Department of Cardiovascular Surgery, the Affiliated Hospital of Guizhou Medical University, Guizhou Province, China
b Department of Cardiac Surgery, Guizhou Hospital, Shanghai Children's Medical Center, Guizhou Province, China
c Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
d Department of Cardiac Surgery, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China
⁎ Corresponding author. Department of Cardiovascular Surgery, the Affiliated Hospital of Guizhou Medical University, Guizhou Province, China. Chenhuiwen@scmc.com.cn
05 9 2024
15 9 2024
05 9 2024
10 17 e3748318 7 2024
3 9 2024
4 9 2024
© 2024 The Authors
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).
Objective

This study aimed to assess the efficacy of a modified exhaust method in pediatric open-heart surgery involving cardiopulmonary bypass.

Method

Data from 303 cases conducted at the Department of Cardiac Surgery, Guizhou Hospital, Shanghai Children's Medical Center, between October 2023 and March 2024 were analyzed. Among these cases, 202 utilized the modified exhaust method, divided into group A (101 cases with median thoracotomy) and group C (101 cases with lateral thoracotomy), while 101 cases used the traditional exhaust method in group B (median thoracotomy). Comparative analysis included general patient data, cardiopulmonary bypass duration, aortic cross-clamp time, time for exhaust and reperfusion upon opening, post-reperfusion ST segment abnormalities on electrocardiogram, intracardiac pneumogram observations via esophageal ultrasound, relevant plasma biochemical indexes on postoperative day one, postoperative drainage volume, duration of ventilator use, and length of stay in the intensive care unit (ICU).

Results

There was no difference in between-group comparisons regarding age (27.98 ± 3.57 vs. 34.05 ± 3.96 months; P = 0.401) and weight (12.23 ± 0.55vs. 12.59 ± 0.70 Kg; P = 0.563). Longer Cardiopulmonary bypass times were observed in patients undergoing median thoracotomy than those undergoing lateral thoracotomy (group B: 108.47 ± 2.30 min vs. group C: 117.03 ± 2.82 min, P = 0.002; group A: 108.91 ± 2.63 min vs. group C: 117.03 ± 2.82 min, P = 0.035). Exhaust and rebound times after opening were significantly shorter in the modified exhaust-method group compared with the traditional-method group (Group A: 52.62 ± 1.39 s vs. Group B: 65.20 ± 1.49 s, P < 0.001; Group B: 65.20 ± 1.49 s vs. Group C: 4.31 ± 1.16 s, P < 0.001). There was no statistical difference in terms of postoperative biochemical indexes, drainage volume, ventilator use time, and ICU stay time (all P > 0.05).

Conclusions

The modified exhaust method demonstrates overall good immediate results in pediatric congenital heart surgery. It was superior to the traditional exhaust method in terms of reducing exhaust times and potentially minimizing the risk of local aortic injuries. Additionally, it appeared to be suitable for lateral thoracotomy surgery.

Keywords

Modified exhaust method
Conventional exhaust method
Open-heart surgery for cardiopulmonary bypass
Congenital heart disease in children
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pmc1 Introduction

Congenital heart disease remains the most birth defect with the prevalence of 0.7–0.9 % worldwide [1]. The open-heart surgery, using cardiopulmonary bypass perfusion strategy, is the standard-of-care procedure for pediatric patients with congenital heart diseases [2]. During the operation, the intracardiac defects will be repaired after aortic cross-clamping. Notably, immediate de-airing is crucial after release of the aortic cross-clamping given that suboptimal evacuation of residual air from the heart potentially increases the risks of cardiac (e.g., gas embolism in the coronary arteries) and neurologic complications, which adversely affects the outcomes especially in neonatal and infantile patients [3,4]. Traditional exhaust method usually requires instruments to enlarge the cannula site of the aortic root to sufficiently evacuate the residual air. However, this maneuver may cause damage to the local aortic wall. Additionally, in some instance such as minimally invasive approach the limited surgical field and suboptimal exposure may be an impediment to complete air evacuation (see Table 1, Fig. 1, Fig. 2).Table 1 Comparison of baseline data between the three groups.

Table 1Clinical data	modified exhaust method	traditional exhaust method	t/z	P-	
A (median thoracotomy)	C (lateral thoracotomy)	B	A & B	A & C	B & C	A & B	A & C	B & C	
Age (month)	27.61 ± 3.80	28.35 ± 3.33	34.05 ± 3.96	−0.138	−1.112	−1.058	0.321	0.270	0.395	
Weight (kg)	11.67 ± 0.53	12.79 ± 0.57	12.59 ± 0.70	−1.030	−1.652	−0.217	0.531	0.170	0.598	
Gender (male)	51 (50.5 %)	44 (43.6 %)	44 (43.6 %)	−1.067	−0.962	0	0.286	0.336	1.000	
 (male)	51 (50.5 %)	44 (43.6 %)	44 (43.6 %)							
 (female)	50 (49.5 %)	57 (56.4 %)	57 (56.4 %)							
aortic blockade time (minutes)	
	44.85 ± 1.60	41.04 ± 1.14	40.79 ± 1.10	1.872	1.501	−0.204	0.064	0.137	0.838	
ST segment abnormalities on electrocardiogram (cases)	
	13 (12.9 %)	15 (14.9 %)	13 (12.9 %)	0.000	−0.425	−0.705	1.000	0.672	0.482	
intracardiac pneumata observed by esophageal ultrasound (cases)	
	22 (21.8 %)	20 (19.8 %)	23 (22.8 %)	−0.445	0.533	1.000	0.657	0.595	0.320	
Troponin (ug/L)	0.028 ± 0.002	0.027 ± 0.032	0.027 ± 0.002	0.861	0.586	−0.134	0.391	0.559	0.894	
creatine phosphokinase isoenzyme (ug/L)	
	16.78 ± 0.47	16.72 ± 0.43	16.80 ± 0.45	−0.146	0.307	0.541	0.884	0.760	0.590	
myoglobin (ug/L)	22.74 ± 0.36	22.48 ± 0.34	22.64 ± 0.33	0.761	1.098	0.786	0.448	0.275	0.434	
NT-Pro BNP(Pg/ml)	146.22 ± 1.53	145.39 ± 1.49	146.50 ± 1.44	−0.541	1.036	1.504	0.608	0.303	0.136	
intraoperative drainage volume (ml)	
	41.49 ± 0.97	41.62 ± 0.96	41.40 ± 0.95	0.535	−0.311	−0.551	0.594	0.757	0.583	
postoperative ventilator use time(h)	
	20.33 ± 1.32	19.76 ± 1.22	20.27 ± 1.31	0.537	1.320	1.221	0.593	0.190	0.225	
postoperative ICU stay time(h)	
	38.28 ± 1.93	38.18 ± 1.86	38.34 ± 1.96	−0.175	0.237	0.382	0.862	0.813	0.704	
cardiopulmonary bypass time (minutes)	
	108.91 ± 2.63	117.03 ± 2.82	108.47 ± 2.30	0.138	−2.140	−3.260	0.890	0.035	0.002	
The time of exhaust and open heart reperfusion (seconds)	
	52.62 ± 1.39	54.31 ± 1.16	65.20 ± 1.49	−6.519	−0.924	5.969	<0.001	0.358	<0.001	
There were no significant differences in general data among the three groups, as well as in the time of aortic blockade, abnormal ST segment on ECG after reperfusion, and intracardiac pneumoplasm observed by esophageal ultrasound, Plasma Biochemical Indexes(For example: Troponin、creatine phosphokinase isoenzyme、myoglobin、NT-Pro BNP), and there was no significant difference in intraoperative drainage volume、postoperative ventilator use time、postoperative ICU stay time.(P > 0.05). However, there was a statistically significant difference in cardiopulmonary bypass time between groups A and C, but not between groups A and B (A & B P = 0.890, A & C P = 0.035, B & C P = 0.002), and the time of exhaust and open heart reperfusion was smaller than that in group B, with statistically significant differences, and no significant difference was observed between group A and group C(A & B P < 0.001, A & C P = 0.358, B & C P < 0.001).

Fig. 1 The modified venting method (median thoracotomy and axillary incision) significantly shortens the time to venting, opening-to-rebound compared with the conventional exhaust.

Fig. 1

Fig. 2 Intracardiac pneumocardiac accumulation observed on esophageal ultrasound after cardiac rebeat (A) and normal ECG and abnormal ECG (B).

Fig. 2

In this study, we have adopted a modification of exhaust method, and sought to assess the efficacy of this procedure as an alternative to the traditional exhaust method.

2 Methods

This study is a retrospective case-control study, involving data from 303 cases of cardiopulmonary bypass open-heart surgery conducted by the same surgeon at the Cardiac Surgery Department of Guizhou Hospital, Shanghai Children's Medical Center, from February 2023 to March 2024. The cohort comprised 139 males and 164 females, with an average age of (27.96 ± 3.04) months and an age range of 1–180 months. Inclusion Criteria: (1) Clear diagnosis of congenital heart disease. (2) Indication for open-heart surgery with cardiopulmonary bypass. (3) Absence of contraindications to surgery based on preoperative evaluation. (4) Informed consent and signed informed consent form for participation in the study. (5) Before the surgical approach of the axillary incision, fully inform the patient and their family of the pros and cons (such as good cosmetic results after surgery but potentially increasing the difficulty of surgical operation and increasing surgical risks, etc.), and let the patient and their family choose for themselves. Exclusion Criteria: (1) Patients requiring correction of aortic malformations. (2) Patients with coronary artery disease. (3) Patients requiring hypothermic circulation arrest during surgery. The patients were divided into the study groups as follows: New exhaust method study group (202 cases), subdivided into group A (median thoracotomy group) with 101 cases (51 males, 50 females, average age (27.61 ± 3.80) months, age range 1–180 months, body weight (11.668 ± 0.53) kg, body weight range 2.5–32 kg) and group C (axillary incision approach) with 101 cases (44 males, 57 females, average age (28.35 ± 3.33) months, age range 1–180 months, body weight (12.79 ± 0.57) kg, body weight range 2.5–32 kg). Traditional exhaust method research group (101 cases), comprising 44 males and 57 females, with an average age of (34.05 ± 3.96) months, age range 1–156 months, body weight (12.59 ± 0.70) kg, and body weight range 3.0–35 kg. There were no significant differences in the general data among the three groups (P > 0.05), ensuring comparability. This study received approval from the Ethics Committee of Guizhou Provincial People's Hospital [Approval No.: Lun Pre-trial Zi (2021) No. 371].1. Samples: The selected sample of patients in the three groups underwent surgery performed by the same surgeon, under general anesthesia, cardiopulmonary bypass, and hypothermia (28–34 °C). Esophageal ultrasound [Norway, GE Vlngmed Ultrasound AS, National Food and Drug Administration (Jin) Zi 2014 No. 3233179] was routinely placed. Patients in groups A and B underwent median sternal incision approach, while those in group C underwent the fourth intercostal approach of the right axillary straight incision. Cannulation of the superior and inferior vena cava and the ascending aorta was established, with a suture purse inserted at the root of the ascending aorta for perfusion tube (BD indwelling needle self-made) [Shanghai, BD Medical Devices (Shanghai) Co., Ltd., National Machinery Injection 20153101935]. Cooling, head lowering, and anterograde perfusion were conducted after aortic occlusion, utilizing blood-containing low-temperature perfusate [Shanghai, Baxter Medical, Sinopharm Quasi-brand H20000475]. A suitable part of the heart was selected for incision, and a left heart drainage tube was inserted to fully decompress the left ventricle. Deformities were exposed and thoroughly corrected, followed by heart closure. The head was kept in a low position, and exhaust from the heart was conducted through the ascending aortic perfusion tube (with intermittent lung expansion and heart shaking). Patients in group B underwent the traditional exhaust method, involving pulling out the perfusion tube and pulling apart the full thickness of the aortic wall at the cannula using a nerve hook during the operation. Patients in groups A and C underwent the new exhaust method, where the perfusion tube was cut 1 cm away from the aortic wall before exhaust, discharged from its stump, and the stump of the perfusion tube was pulled out after heart reperfusion. Following auxiliary circulation cessation, chest closure was performed to complete the operation.

2. Observation indicators: Baseline data of the three groups were collected and compared, including cardiopulmonary bypass time, aortic blockade time, time of reperfusion after exhaust and opening, ST segment abnormalities on electrocardiogram after reperfusion, observation of intracardiac pneumoplasm by esophageal ultrasound after reperfusion, and plasma biochemical indexes on the day after surgery. Parameters were analyzed and compared to draw conclusions. The time of reperfusion after exhaust and opening was defined as the time from the beginning of exhaust to ventricular reperfusion. ST segment abnormalities on ECG included ST segment arching or downward shifting. Esophageal ultrasound observation of intracardiac gas was defined as the presence of numerous snowflake-like bubbles in the heart.

3. Statistical Methods: IBM SPSS 27 software was utilized for statistical analysis. Continuous data were expressed as x ± s, and paired sample t-tests were employed for intergroup comparisons. Count data were expressed as percentages, and the chi-square test was utilized. A significance level of P < 0.05 (two-tailed) was considered statistically significant.

3 Results

There were no significant differences in general data and most of the corresponding observation indicators among the three groups (P > 0.05). However, significant differences were observed in cardiopulmonary bypass time, exhaust time, and rebound time after opening (P < 0.05).

4 Discussion

Cardiopulmonary bypass-assisted open-heart surgery stands as a pivotal approach for effectively correcting intracardiac malformations in children with congenital heart disease. This well-established surgical method is extensively utilized in clinical practice. However, inadequate exhaust during the procedure may result in the introduction of gas into the body, leading to associated embolic complications. Particularly concerning is the potential entry of gas into the coronary circulatory system, which can pose challenges in heart reperfusion or lead to other severe consequences [[5], [6], [7]].

Before cardiopulmonary bypass-assisted open-heart surgery, exhaust gas is directed through right atrial and atrial septal incisions. Efforts are made to remove most of the gas from the heart by adjusting the patient's position, expanding the lungs, and shaking the pericardial cavity. However, some intracardiac and intra-aortic gas may remain, necessitating further removal from the high position of the aortic root. Typically, this residual gas is discharged from the perfusion needle inserted into the aortic cleft. The standard procedure involves pulling out the perfusion needle and using a separate exhaust needle, nerve hook, or other instruments to fully expand the dehiscence at the cleft for exhaust. These commonly used methods ensure accurate exhaust and have been proven effective. However, this method necessitates re-operation along the cleft after removing the perfusion needle, resulting in increased local injury and operation time. In our approach, during surgery, we cut the perfusion needle 1 cm from the aortic wall, utilizing the remaining tube to vent the air. This novel venting method has yielded favorable results. Compared to the traditional exhaust method, this modification did not increase the risk of local aortic injury and can substantially reduce the time between exhaust and cardiac reperfusion. Moreover, this method appeared to be successfully used in the axillary incision approach wherein there is a likelihood of local injury due to procedural inconvenience caused by limited operative field, especially in large weight patients. However, we should clarify that if the perfusion needle is not easy to cut, there is a barrier to adoption of this modified technique. In addition, long-term follow-up results should be required to confirm the effectiveness of this modification of exhaust method. In our study, the samples from the three groups were pairwise compared in terms of cardiopulmonary bypass time. Although the axillary incision approach group (group C) exhibited longer bypass times than the traditional median thoracotomy approach group (group A and B), this is due to the difficulty in exposing the heart during the axillary incision surgery, which makes the surgical operation challenging. [8], this did not compromise the efficacy of the new exhaust method. It confirmed that the new exhaust method also yields positive outcomes in open-heart surgery using this approach. Esophageal ultrasound can be utilized to observe intracardiac gas accumulation during surgery [9]. In cases of incomplete venting during early intraoperative aortic occlusion, “snowflake” residual gas may be observed in the intracardiac atrioventricular cavity. In our study, the incidence of abnormal ECG was compared among the three groups, with no significant difference observed. If coronary gas embolism leads to myocardial ischemia post-reperfusion, early manifestations of myocardial injury can be observed [[10], [11], [12]]. Cardiac enzymes are commonly employed in response to myocardial injury [[13], [14], [15], [16]], with no differences observed among the three groups in our study.

5 Conclusion

This study concluded that the modification of exhaust method can overall yield improved outcomes as compared with traditional exhaust method in terms of reducing exhaust time and potentially minimizing local aortic injuries. In addition, the new exhaust method appeared to be successfully applied in right axillary incision cardiopulmonary bypass open-heart surgery. It is crucial to promptly remove the stump of the perfusion tube after completing exhaust to prevent its retention in the pericardial cavity.

Ethical approval statement

The study has been approved by the Guizhou Provincial People's Hospital Ethics Committee, with the approval number Lun Yu Shen (2021) No. 371. The research adheres to the ethical principles of the Declaration of Helsinki and has obtained informed consent from all participants.

Data availability statement

The data underlying this article will be shared on reasonable request to the corresponding authors.

Funding

2022 Science and Technology Fund Project of Guizhou Provincial Health Commission (gzwkj2022-095 ); 10.13039/501100018555 Science and Technology Program of Guizhou Province (Qian Ke he LH zi [2016] 7181).

CRediT authorship contribution statement

Hong-bo Luo: Writing – original draft, Methodology, Investigation, Formal analysis, Data curation. Kun Shi: i, Data curation. Hui-wen Chen: Supervision, Funding acquisition.

Declaration of competing interest

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Hui-wen Chen reports administrative support was provided by 10.13039/501100010265 Guizhou Medical University . Hong-bo Luo reports article publishing charges, statistical analysis, and writing assistance were provided by The Affiliated Hospital of Guizhou Medical University. Kun Shi reports article publishing charges was provided by Guizhou Provincial People's Hospital. Hui-wen Chen reports a relationship with 10.13039/501100010265 Guizhou Medical University that includes: employment, funding grants, and non-financial support. Hui-wen Chen has patent pending to Guizhou Medical University. no.

If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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