Diaphragmatic Dysfunction as a Predictor of Weaning Outcomes from Mechanical Ventilation in Postoperative Patients with Rheumatic Heart Disease Complicated with Cachexia

Lingai Pan; Fuxun Yang; Xiaoxiu Luo; Xiaoqin Zhang

doi:10.4103/jtccm.jtccm_8_19

ORIGINAL ARTICLE

Year : 2019 | Volume : 1 | Issue : 3 | Page : 100-102

Diaphragmatic Dysfunction as a Predictor of Weaning Outcomes from Mechanical Ventilation in Postoperative Patients with Rheumatic Heart Disease Complicated with Cachexia

Lingai Pan, Fuxun Yang, Xiaoxiu Luo, Xiaoqin Zhang
Intensive Care Unit, Sichuan Provincial People's Hospital, Chengdu, China

Date of Submission	30-Apr-2019
Date of Acceptance	25-Jun-2019
Date of Web Publication	28-Oct-2020

Correspondence Address:
Dr. Xiaoqin Zhang
Intensive Care Unit, Sichuan Provincial People's Hospital, Chengdu 610072
China

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jtccm.jtccm_8_19

Abstract

Background and Objective: This study aims to evaluate the predictive value of the diaphragmatic excursion for weaning from mechanical ventilation in postoperative patients with rheumatic heart disease complicated with cachexia. Methods: Eighty-four postoperative patients with rheumatic heart disease complicated with cachexia who need mechanical ventilation >72 h were enrolled for this prospective study. All patients were evaluated during the weaning process from June 2015 to March 2018. Patients received SBT for 1 h, and we performed ultrasound for the right hemidiaphragm and tested the diaphragmatic excursion. Patients who passed the SBT and no need for reintubation or non-invasive positive pressure ventilation (NIPPV) within 48 h were classified as Group A and others were classified as Group B. Results: We found that the diaphragmatic excursion of Group B (0.76 ± 0.23 cm) was significantly smaller than that of Group A (1.19 ± 0.62 cm), and the oxygen partial pressure of Group B (70.1 ± 9.2 mmHg) was significantly lower than that of Group A (98.6 ± 7.8 mmHg). Conclusion: The assessment of diaphragmatic excursion using ultrasound may be helpful to predict the outcome of weaning for postoperative patients with rheumatic heart disease complicated with cachexia.

Keywords: Cachexia, diaphragmatic excursion, ultrasound, weaning

How to cite this article:
Pan L, Yang F, Luo X, Zhang X. Diaphragmatic Dysfunction as a Predictor of Weaning Outcomes from Mechanical Ventilation in Postoperative Patients with Rheumatic Heart Disease Complicated with Cachexia. J Transl Crit Care Med 2019;1:100-2

How to cite this URL:
Pan L, Yang F, Luo X, Zhang X. Diaphragmatic Dysfunction as a Predictor of Weaning Outcomes from Mechanical Ventilation in Postoperative Patients with Rheumatic Heart Disease Complicated with Cachexia. J Transl Crit Care Med [serial online] 2019 [cited 2023 Mar 31];1:100-2. Available from: http://www.tccmjournal.com/text.asp?2019/1/3/100/299480

Introduction

Syndrome of cardiac cachexia is caused by long-term chronic malnutrition, mainly at the end stage of patients with rheumatic heart disease.^[1] In patients with rheumatic heart disease complicated with cachexia, some may have the problem of diaphragmatic atrophy. In addition to the damage of the cardiac function, patients may need long-term mechanical ventilation, which may lead to further damage to the diaphragmatic function. As the main inspiratory muscle of the human body, the diaphragm plays a role of nearly 70% of the total inspiratory muscle. Prolonged mechanical ventilation may cause complications such as ventilator-induced diaphragmatic dysfunction.^[2] Previous studies have suggested that diaphragmatic dysfunction is one of the important causes of weaning difficulty.^[3],[4] Animal experiments by Radell et al.^[1] have shown that mechanically controlled ventilation for >5 days under intensive care conditions can lead to diaphragmatic dysfunction. Therefore, evaluation of diaphragmatic function is important for weaning in patients with rheumatic heart disease complicated with cachexia. However, methods such as computed tomography and magnetic resonance have the problem of radiation exposure, especially for patients who need high-dose vasoactive drugs. Ultrasound has the advantages of being noninvasive, repeatable, convenient, and accurate.^[5] Therefore, we used ultrasound to monitor the activity of the diaphragm in postoperative patients with rheumatic heart disease complicated with cachexia during spontaneous breathing test (SBT) to find whether the ultrasound results can predict the successful weaning in this category of patients.

Methods

Study design and patient selection

This study was conducted at the Sichuan Provincial People's Hospital from June 2015 to March 2018. Eighty-four postoperative patients with invasive mechanical ventilation ≥72 h who were diagnosed with rheumatic heart disease complicated with cachexia before surgery were considered for inclusion. Diagnostic criteria for cachexia^[6] included (1) weighing <85% of standard weight; (2) Grade III–IV of the heart function; and (3) any two of the following conditions: (a) the disease course was >15 years, (b) liver enlargement and ascites, (c) cardiothoracic ratio >80%, and (d) liver, kidney, and lung moderate or severe dysfunction. Exclusion criteria included (1) patients who are in critical medical condition and might die in the short term; (2) patients complicated with severe metabolic abnormalities such as hyperthyroidism and severe diabetes; (3) patients with hypoxic–ischemic encephalopathy after cardiopulmonary resuscitation; and (4) patients after tracheotomy. Detailed patient records, including gender, age, chest X-ray, and cardiac ultrasound results, were recorded in detail.

For spontaneous breathing trials (SBTa), patients must meet the following criteria: (1) Clinical evaluation: The patient's intubation reasons are corrected and had the ability to cough out the sputum. The attending physician assessed the patient whether they can go to the SBT course; (2) Objective indicators: (1) Good consciousness. (2) Stable hemodynamic (heart rate [HR] maintained at 60–120 beats/min, systolic blood pressure 90–140 mmHg, low-dose vasoactive drugs maintained); (3) Stable internal environment, no acidosis. (4) Good oxygenation status under low mechanical ventilation support (positive end expiratory pressure [PEEP] ≤5–8 cm H₂O, FiO₂≤40% SPO₂≥92%–95%, respiratory rate ≤35 times/min, VT ≥5 mL/kg).

Grouping method

The patient was classified into Group A if successfully weaning off from ventilation and no intubation or use of noninvasive ventilator within 48 h. Otherwise, the patient was classified into Group B (the failed weaning group).

Ultrasound examination

Diaphragmatic ultrasound was performed by a physician with the chinese critical ultrasound study group (CCUSG) certification, using the Philips iE Elite 1–5 HZ convex probe for diaphragmatic examination. The patient was placed in a supine position with a bed elevation of 30°–45°, and the liver was used as a sound window to measure the mobility and thickness of the right diaphragm. Under the right rib margin and the right anterior line intersection, use the two-dimensional mode to ensure that the D line and the posterior iliac muscle are perpendicular, select the M mode, measure the diaphragmatic muscle activity, and record five breath cycles to get the average value.

The following information was collected: patient's gender, age, APACHE II score, mechanical ventilation time, HR, mean arterial pressure, blood gas analysis, and other indicators, and we recorded the diaphragmatic activity after 1 h of SBT.

Statistical analysis

Statistical analysis was performed using SPSS19.0 (SPSS INC, Chicago, IL, USA). Average date was expressed as mean ± standard deviation. Independent sample t-test or Mann–Whitney U-test was used to compare continuous variables, and Chi-square test or Fisher's exact test was used for categorical variables. Group differences with P < 0.05 were considered statistically significant.

Results

In this study, 58 patients were successfully weaning from the ventilation, and 26 patients failed. There were no significant differences in the basic clinical characteristic data, valvular heart lesion type, and hemodynamic status between the two groups (P > 0.05) [Table 1]. The diaphragmatic movements of the two groups were measured 1 h after SBT. Patients in Group A had a diaphragmatic movement of 1.19 ± 0.62 cm and a partial pressure of oxygen (PaO₂) of 98.6 ± 7.8 mmHg, whereas patients in Group B had a diaphragmatic movement of 0.76 ± 0.23 cm and a PaO₂ of 70.1 ± 9.2 mmHg. The diaphragmatic movements and PaO₂ values in Group B were significantly smaller than that in Group A (P < 0.05) [Table 2].

Table 1: Baseline demographics and clinical characteristics

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Table 2: Comparison of diaphragmatic movements and partial pressure of oxygen 1 h after spontaneous breathing test between two groups

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Discussion

Whether the critically ill patients can successful wean from ventilation depends on a variety of factors, of which diaphragmatic function plays an important role. Diaphragmatic potential monitoring and transpulmonary pressure monitoring are often used, but these methods are generally difficult to implement for critically ill patients.^[7] Previous studies have confirmed that ultrasound assessment of diaphragmatic changes has a good correlation with traditional methods and has a certain guiding role for planed weaning patients.^[8] Ultrasound is now clinically known as “visible stethoscope,” which can monitor the diaphragmatic changes in real time. To ensure that our measurement results are highly accurate, the doctors in this study have undergone rigorous intensive ultrasound training.

For patients with rheumatic heart disease, heart dysfunction and long-term illness often lead to extremely poor nutritional status and weight loss. In addition, patients of this group often have some severe complications such as pulmonary hypertension and prolonged mechanical ventilation. Weaning remains a challenging issue for these patients. Studies have shown that mechanical control ventilation for >12 h may make diaphragmatic muscle fiber atrophy, which further induces a decline in contractile function.^[9] Therefore, this study attempted to analyze the diaphragmatic movements of the two groups after rheumatic heart disease combined with cachexia to guide weaning from ventilation. Using ultrasound to measure the diaphragmatic mobility 1 h after SBT, the mobility of the failed group was significantly reduced as compared with the successful weaning group, along with a significant decrease in oxygen partial pressure. This result is similar to previous findings. Xu et al.^[10] and other studies have shown that ultrasound has predictive value in chronic obstructive pulmonary disease (COPD) patients. When using the diaphragmatic movement 1 h after SBT (1.043 cm as the cutoff) to predict the severity of COPD weaning difficulty, the sensitivity was 73.8% with the specificity of 89.5%. Our findings may have the following implications: (1) rheumatic heart disease patients have long-term gastrointestinal congestion and edema which may lead to poor nutritional status. Moreover, the long-term chronic malnutrition may make the diaphragmatic atrophy.^[11] Early postoperative initiation of enteral nutrition under the guidance of ultrasound can improve the nutrition status has been confirmed in previous studies;^[12] (2) postoperative pulmonary hypertension may increase the difficulty for weaning. We can use sildenafil or some other drugs to decrease pulmonary artery pressure and use bedside ultrasound to dynamically monitor pulmonary artery pressure changes in real time to guide the weaning;^[13] and (3) as mentioned above, prolonged mechanical ventilation could lead to diaphragmatic atrophy. Therefore, we may need to use the spontaneous ventilation mode to make the diaphragmatic muscle fully exercised. During the process, the ultrasound can be used to dynamically monitor the diaphragmatic function in real time to find the best time point for weaning.

Conclusion

The assessment of diaphragmatic excursion using ultrasound may be helpful to predict the outcome of weaning for postoperative patients with rheumatic heart disease complicated with cachexia.

Limitations

There are still some limitations in this study. First, mechanical ventilation has a complicated mechanism of influence on diaphragmatic function, including mechanical ventilation time, mode, and sedative and analgesic drugs. These factors are not included in this study. Second, the activity of the diaphragm is greatly influenced by the patient's own inhalation effort, which may affect the results of the measurement. Nevertheless, the evaluation of diaphragmatic function by ultrasound still has some guiding value for clinical doctors.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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