Case report

Noninvasive Ventilation for Awake Percutaneous Aortic Valve Implantation in High-Risk Respiratory Patients: A Case Series

Understanding vegetation dynamics and its response to climate changes is important for revealing the mechanisms of terrestrial ecosystem behaviour, predicting future vegetation growth, and thus guiding environmental management. The Jing River Basin (JRB) and the Beiluo River Basin (BLRB), two typical ecoenvironmentally vulnerable regions on the Loess Plateau in China, were selected as case study regions. Based on long-term Normalized Difference Vegetation Index (NDVI) datasets, the time-lag relationships between NDVI and climatic factors (precipitation/temperature) as well as teleconnection factors (large-scale modes of climate variability and solar activity) were revealed. Additionally, ridge regression models were established to quantitatively explore the response of vegetation dynamics to climate change. Results indicate that: (1) NDVI in autumn showed significantly increasing trend (p < 0.01), whereas that in spring and summer was insignificant; (2) there was a time-lag of more than one month between spring/winter NDVI and precipitation/temperature behaviour, and summer NDVI exhibited no lag with temperature but a one month lag with precipitation; (3) regarding the time-lag effects, precipitation was the driving factor of NDVI variations in spring, whereas sunspots dominated NDVI variations in autumn; (4) when time-lagged teleconnection factors were considered, the explanation of the climate effect on the vegetation dynamics in three seasons all relatively increased by >95%, which indicates that the prediction accuracy of NDVI was significantly improved; (5) in summer, time-lagged climatic and teleconnection factors explained <20% of NDVI variations, whereas when soil moisture and base flow were considered, the explanation of NDVI changes in the JRB and BLRB relatively increased by 37.4% and 65.1%, respectively. These findings highlight that considering the time-lag effect of climatic and teleconnection factors has important significance for the accurate monitoring of underlying surface dynamics under changing environment.

Describe the change in intraoperative transcatheter aortic valve replacement (TAVR) care by examining the utilization of transesophageal echocardiography (TEE) versus transthoracic echocardiography (TTE) and general anesthesia (GA) versus conscious sedation (CS) over time.

Retrospective, observational.

A university, single, high-volume TAVR center.

Patients who underwent TAVR.

Retrospective data collection from the electronic medical records on TAVR patients at a single institution from March 1, 2014 to August 31, 2017. The intraoperative echocardiographic modality, anesthetic type, Society of Thoracic Surgeons (STS) operative mortality risk score, and date each new TAVR valve first was employed at the institution were recorded.

Data were analyzed using descriptive statistics apportioned into 6-month intervals. The Fisher exact test and chi-square test were used to test the association of anesthesia type and echocardiography over time, respectively. STS score, anesthetic type, and echocardiographic type were compared using the Wilcoxon rank sum test.

Analysis showed increased use of TTE and CS, from 0% and 0% intially to 68.42% and 63.16% most recently (p < 0.0001). In the final study period (after March 1, 2017), the use of TTE and CS surpassed TEE and GA, respectively. STS scores were significantly higher among patients having TEE versus TTE (median STS 6.34 v 4.45, respectively [p = 0.0047]) and GA versus CS (median STS 6.36 v 4.37, respectively [p = 0.0090]).

Although TAVR initially was conducted exclusively under GA with TEE, nearly two-thirds of TAVR procedures now are performed using CS and TTE at the authors’ institution. STS scores were significantly lower in patients having CS and TTE.

Transcatheter aortic valve implantation (TAVI) has become the mainstay for high-risk or inoperable patients with symptomatic aortic valve stenosis, and research regarding the use of transcatheter valves in intermediate or low-risk patients is currently ongoing. The aim of this article is to provide comprehensive insight into the anesthetic management of patients undergoing TAVI and to highlight possible gaps in the current knowledge. One important procedural characteristic that is imperative to consider is the type of anesthesia being used and its possible complications. Increasingly, experienced centers have changed from general anesthesia with endotracheal intubation to local anesthesia with sedation, especially when the transfemoral access route is used for TAVI. There is still debate regarding what type of anesthesia should be used in the procedure, and the lack of randomized data makes it even more challenging for the operators.

Transcatheter aortic valve implantation (TAVI) is a treatment strategy for patients with severe aortic stenosis. Although general anaesthesia (TAVI-GA) and sedation (TAVI-S) have previously been described for TAVI, the difference in safety and efficacy of both methods has not been studied in a randomized trial.

The INSERT trial was a single centre, controlled parallel-group trial with balanced randomization. Sixty-six patients (68–94 yr) with acquired aortic stenosis undergoing transfemoral CoreValve™ were assigned to TAVI-GA or TAVI-S. Comparable operative risk was determined from risk-scores (EUROscore, STS-Score). Monitoring and anaesthetic drugs were standardized. Near-Infrared-Spectroscopy was used to monitor cerebral-oxymetry blinded. Primary outcome was the perioperative cumulative cerebral desaturation. As secondary outcomes, changes in neurocognitive function and respiratory and haemodynamic adverse events were evaluated.

Of 66 included patients, 62 (TAVI-GA: n+31, TAVI-S: n+31) were finally analysed. Baseline characteristics were comparable. In 24 patients (39%) cerebral desaturation was observed. Cumulative cerebral desaturation was comparable (TAVI-GA:(median [IQR]) (0[0/1308] s%) vs. TAVI-S:(0[0/276] s%); P+0.505) between the groups. Neurocognitive function did not change within and between groups. Adverse events were more frequently observed in TAVI-S patients (P<0.001). Bradypnoea (n+16, 52%) and the need for airway manoeuvres (n+11, 36%) or bag-mask-ventilation (n+6, 19%) were the most common respiratory adverse events.

Cerebral desaturation occurred in both patient groups, but there was no significant difference between the two groups. Based on primary outcome, both methods were shown to be comparable. Neurocognitive outcome was similar. The higher incidence of adverse events in the sedation group suggests a potential advantage of general anaesthesia.

NCT 01251328.