Inhaled nitric oxide reduces the intrapulmonary shunt to ameliorate severe hypoxemia after acute type A aortic dissection surgery

Study on risk factors and treatment strategies of hypoxemia after acute type a aortic dissection surgery

Acute type A aortic dissection is a life-threatening cardiovascular disease characterized by rapid onset and high mortality. Emergency surgery is the preferred and reliable treatment option. However, postoperative complications significantly impact patient prognosis. Hypoxemia, a common complication, poses challenges in clinical treatment, negatively affecting patient outcomes and increasing the risk of mortality. Therefore, it is crucial to study and comprehend the risk factors and treatment strategies for hypoxemia following acute type A aortic dissection to facilitate early intervention.

Effect of pre-operative hypoxemia on the occurrence and outcomes of post-operative ARDS in Stanford type a aortic dissection patients

BACKGROUND

Pre-operative and post-operative hypoxemia are frequent complications of Stanford type A aortic dissection (AAD). This study explored the effect of pre-operative hypoxemia on the occurrence and outcome of post-operative acute respiratory distress syndrome (ARDS) in AAD.

METHOD

A total of 238 patients who underwent surgical treatment for AAD between 2016 and 2021 were enrolled. Logistic regression analysis was conducted to investigate the effect of pre-operative hypoxemia on post-operative simple hypoxemia and ARDS. Post-operative ARDS patients were divided into pre-operative normal oxygenation group and pre-operative hypoxemia group that were compared for clinical outcomes. Post-operative ARDS patients with pre-operative normal oxygenation were classified as the real ARDS group. Post-operative ARDS patients with pre-operative hypoxemia, post-operative simple hypoxemia, and post-operative normal oxygenation were classified as the non-ARDS group. Outcomes of real ARDS and non-ARDS groups were compared.

RESULT

Logistic regression analysis showed that pre-operative hypoxemia was positively associated with the risk of post-operative simple hypoxemia (odds ratios (OR) = 4.81, 95% confidence interval (CI): 1.67-13.81) and post-operative ARDS (OR = 8.514, 95% CI: 2.64-27.47) after adjusting for the confounders. The post-operative ARDS with pre-operative normal oxygenation group had significantly higher lactate, APACHEII score and longer mechanical ventilation time than the post-operative ARDS with pre-operative hypoxemia group (P < 0.05). Pre-operative the risk of death within 30 days after discharge was slightly higher in ARDS patients with pre-operative normal oxygenation than in ARDS patients with pre-operative hypoxemia, but there was no statistical difference(log-rank test, P = 0.051). The incidence of AKI and cerebral infarction, lactate, APACHEII score, mechanical ventilation time, intensive care unit and post-operative hospital stay, and mortality with 30 days after discharge were significantly higher in the real ARDS group than in the non-ARDS group (P < 0.05). After adjusting for confounding factors in the Cox survival analysis, the risk of death within 30 days after discharge was significantly higher in the real ARDS group than in the non-ARDS group (hazard ratio(HR): 4.633, 95% CI: 1.012-21.202, P < 0.05).

CONCLUSION

Preoperative hypoxemia is an independent risk factor for post-operative simple hypoxemia and ARDS. Post-operative ARDS with pre-operative normal oxygenation was the real ARDS, which was more severe and associated with a higher risk of death after surgery.

The association between lymphocyte-monocyte ratio and postoperative acute kidney injury in patients with acute type A aortic dissection

BACKGROUND

The aim of this study was to investigate the relationship between baseline lymphocyte-monocyte ratio (LMR) and postoperative acute kidney injury (AKI) in patients with acute type A aortic dissection (ATAAD).

METHODS

ATAAD patients undergoing surgery in Nanjing First Hospital were enrolled from January 2019 to April 2021. Lymphocyte and monocyte were measured on admission. Multivariable logistic regression analyses were performed to explore the relationship between LMR and postoperative AKI. We also used receiver operating characteristic (ROC), net reclassification index (NRI) and integrated discrimination improvement (IDI) analyses to assess the predictive ability of LMR.

RESULTS

Among the 159 recruited patients, 47 (29.6%) were diagnosed with AKI. Univariate logistic regression analysis indicated that ATAAD patients with higher levels of LMR were prone to have lower risk to develop AKI (odds ratio [OR], 0.493; 95% confidence interval [CI] 0.284-0.650, P = 0.001). After adjustment for the potential confounders, LMR remained an independent related factor with postoperative AKI (OR 0.527; 95% CI 0.327-0.815, P = 0.006). The cutoff value for LMR to predict AKI was determined to be 2.67 in the ROC curve analysis (area under curve: 0.719). NRI and IDI further confirmed the predictive capability of LMR in postoperative AKI.

CONCLUSION

Elevated baseline LMR levels were independently associated with lower risk of postoperative AKI in ATAAD patients.

Nitric Oxide Inhalation Therapy Attenuates Postoperative Hypoxemia in Obese Patients with Acute Type A Aortic Dissection

Objective

To investigate the differences between inhaled nitric oxide (iNO) treatment and conventional therapy in the treatment of postoperative hypoxemia in obese patients with acute type A aortic dissection (ATAAD).

Methods

ATAAD patients diagnosed and treated with emergency surgery in our hospital from June 2017 to December 2019 were retrospectively analyzed. Patients with postoperative hypoxemia were divided into the iNO group and control group. Propensity score matching was used to analyze clinical characteristics and results of the two groups.

Results

A total of 218 ATAAD patients with BMI ≥ 25 were treated with surgery. Among them, 115 patients developed refractory hypoxemia (64 in the control group and 51 in the iNO group). Patients in the iNO group had significantly shorter invasive mechanical ventilation time, intensive care unit (ICU) stay, and hospital stay. After 6 h of iNO treatment, the PaO2/FiO2 ratio in the iNO group increased significantly, and this ratio was higher than that in the control group at 6, 12, 24, 48, and 72 h after treatment.

Conclusion

Low-dose iNO could improve oxygenation and shorten mechanical ventilation and ICU stay in patients with hypoxemia after ATAAD surgery, but without significant side effects or increase in postoperative mortality or morbidity. These findings provide a basis for a randomized multicenter controlled trial to assess the efficacy of iNO in the treatment of hypoxemia after ATAAD surgery.