The incidence of POAF in our study (10.5% ) was greater than reported in the previous studies (3.5–8.6%) [1–4]. Our team performs post-surgery electrocardiogram monitoring within 24–72 hours, detecting potential or transient POAF cases. Additionally, the patients in our study had a higher age threshold (73 years) than previous[2,3]. These factors may explain the higher incidence of POAF than in other studies.
Preceding studies consistently reported a correlation between POAF and extended hospitalizations[2]. Our findings revealed that patients who improved POAF experienced a significantly longer median postoperative hospital stay of 11 days compared to those who did not develop POAF, with a median stay of 9 days (p < 0.05). Furthermore, the group of patients with POAF exhibited significantly longer drainage time and higher drainage volume. To evaluate the potential relationship between platelet counts and drainage volume, we conducted an analysis; however, we found no significant differences between the POAF and non-POAF (n-POAF) groups (p > 0.05).
Prior research consistently indicated that POAF tends to manifest within the initial three days post-surgery[1, 2]. Our findings demonstrated the highest POAF incidence (51.7%) on the first day after surgery, with 25 of 29 cases arising within three days post-surgery. This early occurrence could intensify sputum production during the initial 24–72 hours post-surgery, potentially leading to acute hypoxia. Pain and anesthesia directly impact respiration and cough reflex, adding to POAF incidence. It's vital to note that POAF usually diminishes over time and is often a result of surgical trauma, hypoxia, and other stressors rather than organic heart disease. Hence, POAF post lung resection is commonly transient and temporary.
Amiodarone and digoxin have been recommended by researchers for managing POAF effectively[11]. These drugs have demonstrated safety and can be easily administered during invasive procedures. Our study assessed their efficacy in POAF treatment. Treatment with amiodarone or digoxin led to clinical improvement in 26 cases and spontaneous sinus rhythm conversion in 3 cases (10.3%). Within 24 hours, 22 of 32 patients reverted to sinus rhythm, while 3 continued to experience atrial fibrillation and received anticoagulation therapy upon discharge. Symptomatic patients reported palpitations and chest tightness, yet all maintained stable hemodynamics without significant discomfort.
In 2002, Amar's study[12] highlighted increased POAF incidence with age among patients aged 60 + undergoing chest surgery, marking this age group as a risk factor. Subsequent research confirmed this[1, 5, 9]. Our study focused on NSCLC patients undergoing VATS, setting the age cutoff at 73 years. For patients over 73, POAF incidence (34.5%) was notably higher than non-POAF (18.6%, P = 0.045). Surprisingly, our multivariate analysis didn't confirm age as an independent POAF risk, differing from prior findings[12]. This may stem from our higher age threshold and the specific NSCLC VATS focus. Further multicenter prospective studies are needed for deeper insights.
Furthermore, previous studies have reported that the incidence of POAF increases when the surgical duration exceeds 180 minutes [13]. In our study, the cut-off value for surgical duration was also set at 180 minutes, consistent with the mentioned research[13]. Although the final results did not show surgical duration as a significant factor influencing POAF, we still recommend controlling the surgical time to be within 180 minutes whenever possible.
Existing research shows that the extent of lung resection can affect POAF development. Vaporciyan et al.[8] found similar POAF rates in patients who had single or multiple wedge resections. This trend persisted even with increased tissue resection, without corresponding POAF rise. Our study classified lung resection into five groups: wedge, segmentectomy, lobectomy, bi-lobectomy, and pneumonectomy. We didn't observe significant POAF differences among these groups, aligning with Vaporciyan's findings[8]. Another study[3] found lower POAF rates in segmentectomy (1.4%) than lobectomy (2.8%). Additionally, earlier research[2,14] has singled out pneumonectomy as a significant independent POAF risk. Multiple studies propose a direct link between tissue loss during lung resection, reduced post-op lung function, inadequate myocardial oxygen, and potential POAF[4,9]. Therefore, lung tissue resection extent could impact POAF onset.
Mediastinal lymph node dissection may influence the incidence of POAF, potentially leading to direct damage to the cardiac plexus at the aortic arch and tracheal bifurcation. Some experts [1,2, 15] have hypothesized that mediastinal lymph node dissection could trigger atrial fibrillation, increasing the risk of POAF. However, a study[16] argues that there is no significant association between them.
We separately analyzed mediastinal lymph nodes retrieved and node stations explored. Median nodes retrieved were 10 in POAF, 6 in n-POAF. Median stations explored were 3 in both groups. Differences were statistically significant (P < 0.05). However, multivariate analysis showed retrieved nodes and explored stations minimally affect POAF.
Due to missing pulmonary function test data, this study employed blood gas analysis, red blood cell count, and hemoglobin content as oxygen level indicators. Except for hemoglobin (P = 0.048), other findings showed no substantial differences in these metrics between groups (P > 0.05). Nonetheless, further data collection and prospective studies are essential to ascertain lung function's impact on POAF.
Local inflammation is widely acknowledged as a POAF risk, supported by scholars [11, 17, 18]. Previous studies linked POAF incidence to interleukin 2, interleukin 6, and C-reactive protein (CRP) levels[18–20]. Boons et al.[17] tied prolonged ventilation and lung infections to POAF in cardiothoracic patients. Implementing preventive measures like low-flow oxygen inhalation might lower POAF, but this has been debated[21]. Our study found pulmonary infection, accounting for 72.2% (70/97) of complications, significantly linked to POAF (P < 0.001). Multivariate analysis affirmed pulmonary infection as an independent POAF risk. Post-op infection markers (white blood cells, neutrophils, CRP) showed no notable differences, aligning with prior research[21]. Blood biomarker studies yield inconsistent outcomes, likely due to unique heart effects[22–23].
The study has two strengths. Firstly, prior research indicated that lung resection can impact cardiac function, leading to arrhythmias[24]. However, these studies overlooked surgery-related fluid administration. Cautious fluid management during surgery is crucial to prevent cardiac overload, pulmonary edema, and respiratory infections. The study shows no significant differences in fluid volume between the POAF and non-POAF groups, demonstrating our expertise in fluid management. However, larger-scale research is needed to explore the correlation between fluid infusion and POAF. Secondly, continuous ECG monitoring for at least three days in the majority of patients ensured accurate POAF incidence during hospitalization. Additionally, the study's strength lies in selecting VATS techniques for surgery in NSCLC patients, offering valuable insights to thoracic surgeons.
However, this study has limitations. Firstly, being a retrospective study without randomization reduced its control, slightly affecting the findings. Secondly, incomplete data collection on outcomes like pulmonary function and pain hindered their examination. Thirdly, the small sample size and limited AF incidence hindered comprehensive analysis of risk factors. Lastly, the study found that NSCLC stage didn't notably impact POAF development. Notably, our study lacked further analysis on lymph node involvement and tumor size in relation to POAF. Thus, more exploration through multicenter prospective studies is needed.
In conclusion, postoperative pulmonary infection is a risk factor for POAF following VATS treatment for NSCLC. POAF leads to extended drainage and hospital stays. To prevent this, proactive anti-infective therapy and physical interventions post-surgery can effectively decrease pulmonary infections and lower the occurrence of POAF.