Hypothermia Is Associated With Increased Mortality in Patients Undergoing Repair of Ruptured Abdominal Aortic Aneurysm

Comparative Efficacy of Six Active Warming Systems for Intraoperative Warming in Adult Patients Undergoing Laparoscopic Surgery: A Systematic Review and Network Meta-Analysis

Intraoperative hypothermia is very common and harmful in adult patients undergoing laparoscopic surgery. A variety of active warming systems has received close attention and has been researched by related scholars. However, the relative efficacy of these systems and which active warming system is preferred for such patients remain unclear. The aim of this study was to compare and rank six active warming systems regarding intraoperative warming efficacy in adult patients undergoing laparoscopic surgery. Following the PRISMA 2020 guidelines, relevant randomized controlled trials (RCTs) on the efficacy of different active warming systems in warming adult patients undergoing laparoscopic surgery were searched from five English databases and three Chinese databases. The quality of the studies was assessed using the Cochrane Risk of Bias tool (RoB2). The outcome was the final intraoperative core temperature. We estimated direct effects by using pairwise meta-analysis, estimated relative effects and ranking with the consistency model to conduct an NetworkMeta-Analysis (NMA). We used GRADE (Grading of Recommendations Assessment, Development, and Evaluation) to assess the certainty of the evidence. Sensitivity analysis was performed to test the robustness of the results. This study is registered with PROSPERO, with number CRD42022309057. In total, 19 RCTs involving 6 active warming systems and comprising 1364 patients were included in this NMA. The NMA once again confirmed the validity of forced-air warming (FAW) systems compared with other active warming systems, and further showed that underbody FAW was associated with more remarkable warming efficacy in different types of FAW systems. NMA was used to perform an exhaustive comparison of the warming efficacy of six active warming systems and indicated that underbody FAW was most likely to be the most effective warming system in adult patients undergoing laparoscopic surgery; however, considering the sparsity of the network, our results should be cautiously interpreted. Furthermore, a large number of high-quality RCTs comparing the warming efficacy of different competitive active warming systems are needed.

Artifacts in fluoroscopy and changes in radiation dose caused by heating blankets and insulating covers during simulated endovascular treatment

PURPOSE

We aimed to assess whether insulating covers and warming systems cause artifacts in fluoroscopy, and whether they alter the radiation dose.

METHODS

Eight insulating and warming systems were wrapped around the phantom in order to obtain images in fluoroscopy, and to measure the absorbed and scattered radiation dose. A dosimeter, endovascular catheters, and stents were placed into a phantom. The other dosimeter was placed outside of a C-arm table, at the operator's and anesthesiologist's locations.

RESULTS

Most of the insulating covers did not cause artifacts in the fluoroscopy and led to a significant decrease in both the absorbed and scattered radiation dose. The highest decrease in the absorbed dose was observed with metalized foil (- 2.09%; p = 0.001) and in the scattered dose with Helios cover (- 55%; p < 0.001). Only one heating system (Ready Heat combined with Hypothermia Prevention and Management Kit cover) caused significant artifacts and increased radiation up to 99% (p < 0.001).

CONCLUSION

Thermal insulation may be maintained during X-ray-guided emergency endovascular procedures in trauma victims. Self-heating blankets should be replaced with another warming system.

The Significance of Hypothermia in Abdominal Aortic Aneurysm Repair

BACKGROUND

The aim of this study was to review the literature on the association between hypothermia and outcomes in open and endovascular abdominal aortic aneurysm (AAA) repair. The secondary aim was to determine whether there is a difference in body temperature in patients undergoing either transperitoneal (TP), retroperitoneal (RP), or endovascular surgical repair of the abdominal aorta (EVAR).

METHODS

MEDLINE, Web of Science, and Trip searched for all studies on temperature in the context of aortic surgery or endovascular aortic interventions. To be included in the review, the papers had to be related to intraoperative or postoperative hypothermia and/or normothermia, with regards to either open or endovascular repair of the abdominal aorta. Thoracic or thoracoabdominal aortic repairs were not included for review.

RESULTS

Eight studies involving 765 patients were eligible. Of these, 6 studies looked at open elective AAA repair involving 605 patients. Only 2 studies investigated emergency AAA repair and consisted of 160 patients where only 35 of those patients underwent emergency EVAR. Normothermic patients had a shorter length of stay in the intensive care unit (P = 0.0008), while hypothermia was independently associated with higher rates of organ dysfunction, in-hospital mortality, and prolonged hospital length of stay. In ruptured AAAs, the lowest average intraoperative temperature was recorded in open repair compared with EVAR (P = 0.02). There was no statistically significant difference in postoperative temperature between patients undergoing elective RP repair and those having TP surgery.

CONCLUSIONS

The studies identified in this review have shown that hypothermia has numerous deleterious effects on outcomes in AAA repair - whether or not these adverse outcomes are those such as higher rates of organ dysfunction, mortality or prolonged hospital length of stay, can only be done at the single paper level and not at a literature review level, due to multiple confounding variables. Despite these limitations, the benefits of this review are numerous. This article highlights the importance of core body temperature and outcomes of AAA repair. Furthermore, it brings forth the need to standardize the method of core body temperature measurement and method of rewarming. Given the body of evidence so far, these standardized data collection points will be important for national vascular quality improvement initiatives. Only through rigorous analysis of standardized dataset can firm recommendation regarding peri- and postoperative temperature management be made.

Surgical and anesthetic considerations for the endovascular treatment of ruptured descending thoracic aortic aneurysms

PURPOSE OF REVIEW

Ruptured descending thoracic aortic aneurysm (rDTAA) is a life-threatening disease. In the last decade, thoracic endovascular aortic repair (TEVAR) has evolved as a viable option and is now considered the preferred treatment for rDTAAs. New opportunities as well as new challenges are faced by both the surgeon and the anesthesiologist. This review describes the impact of current developments and new modalities for the surgical and anesthetic management of rDTAAs.

RECENT FINDINGS

A collaborative approach between the anesthesiologist and surgeon during critical moments such as induction, moment of aortic occlusion and placement of the aortic stent-graft is mandatory. Important issues to consider on preoperative imaging evaluation are correct sizing of the aortic stent-graft and localization of the artery of Adamkiewicz. Emergency TEVAR should preferentially be started under local anesthesia and could be switched to general anesthesia after stent placement. Patients should be kept in permissive hypotension preoperatively and during the intervention before stent-graft deployment and relative hypertension after deployment. The use of a proactive spinal cord protection protocol could decrease the risk of spinal cord ischemia and/or paraplegia and consists of permissive hypertension after stent deployment, cerebrospinal fluid drainage to maintain adequate spinal cord perfusion, relative hypothermia and possibly use of mannitol.

SUMMARY

In order to improve outcomes of TEVAR for rDTAA, a close communication between the anesthesiologist and the surgeon and a thorough understanding of the events during the procedure is mandatory. The use of a proactive spinal cord protection protocol may decrease the rates of devastating spinal cord ischemia.

Effect of regional cooperation on outcomes from ruptured abdominal aortic aneurysm

BACKGROUND

Care for patients with a ruptured abdominal aortic aneurysm (rAAA) in the Amsterdam ambulance region (The Netherlands) was concentrated into vascular centres with a 24-h full emergency vascular service in cooperation with seven referring regional hospitals. Previous population-based survival after rAAA in the Netherlands was 46 (95 per cent confidence interval (c.i.) 43 to 49) per cent. It was hypothesized that regional cooperation would improve survival.

METHODS

This was a prospective observational cohort study carried out simultaneously with the Amsterdam Acute Aneurysm Trial. Consecutive patients with an rAAA between 2004 and 2011 in all ten hospitals in the Amsterdam region were included. The primary outcome was 30-day survival after admission. Multivariable logistic regression, including age, sex, co-morbidity, intervention (endovascular or open repair), preoperative systolic blood pressure, cardiopulmonary resuscitation and year of intervention, was used to assess the influence of hospital setting on survival.

RESULTS

Of 453 patients with rAAA from the Amsterdam ambulance region, 61 did not undergo intervention; 352 patients were treated surgically at a vascular centre and 40 at a referring hospital. The regional survival rate was 58.5 (95 per cent c.i. 53.9 to 62.9) per cent (265 of 453). After multivariable adjustment, patients treated at a vascular centre had a higher survival rate than patients treated surgically at a referring hospital (adjusted odds ratio 3.18, 95 per cent c.i. 1.43 to 7.04).

CONCLUSION

After regional cooperation, overall survival of patients with an rAAA improved. Most patients were treated in a vascular centre and in these patients survival rates were optimal.

Intraoperative hypothermia is associated with an increased intensive care unit length-of-stay in patients undergoing elective open abdominal aortic aneurysm surgery: a retrospective cohort study

Intraoperative hypothermia in open elective abdominal aortic aneurysm repair may be associated with increased hospital morbidity. This retrospective, single centre study investigated whether there was an association between intraoperative hypothermia in open elective abdominal aortic aneurysm repair and postoperative in-hospital morbidity. The data of 119 patients who underwent open infrarenal abdominal aortic aneurysm repair between January 2006 and January 2011 were collected. The electronic databases from the hospital, intensive care unit, transfusion medicine and operating theatres were linked by the patient's unique identifiers including date of birth and unit record number. Intraoperative nasopharyngeal temperature measurements were collected manually from paper-based anaesthetic records. The study group included 102 out of the 119 patients. Sixty-six patients (64.6%) had intraoperative hypothermia as defined by temperature <36°C. Intraoperative temperature was not predictive of hospital length-of-stay or any of the other perioperative complications such as acute renal failure, acute respiratory complications, acute myocardial infarction, transfusion requirements or postoperative infection. In the normothermic group, the number of hours in the intensive care unit was 35% lower (ratio of means=0.65; 95% confidence interval 0.51 to 0.84; P=0.0008), even after adjusting for possible confounders such as age, duration of anaesthesia, size of aneurysm, comorbidities and transfusion. Intraoperative hypothermia is a persisting problem and more aggressive warming strategies may need to be identified and employed to achieve normothermia.

Multicenter audit of emergency endovascular repair of infrarenal aortic aneurysms

BACKGROUND

Emergency endovascular aneurysm repair (eEVAR) for infrarenal abdominal aortic aneurysm has become widely accepted as an alternative to open repair, if the aortic anatomy is favorable and endovascular expertise is readily available. The aim of this study is to report the outcome of eEVAR in Hong Kong.

METHODS

This was a retrospective review of prospectively collected data from Hong Kong Hospital Authority Clinical Data Analysis and Reporting System (CDARS), Clinical Management System (CMS), and departmental prospective computerized databases. Patient demographics, clinical and biochemical parameters, perioperative complications, and outcomes were recorded and analyzed. The independent sample t-test was used for continuous variables and the Fisher's exact test was used for nonparametric variables. Kaplan-Meier analysis was performed for overall survival and survival of subgroups. Binary logistic regression was performed for factors predicting perioperative mortality. SPSS software (version 15.0; SPSS Inc., Chicago, IL) was used for all statistical analyses.

RESULTS

A total of 40 patients (36 men with a mean age of 74.9 ± 1.53 years [range: 52-89 years]) underwent emergency eEVAR between January 2006 and September 2011 in 6 Hospital Authority Hospitals in Hong Kong. All patients were treated using commercially available aortoiliac endografts (including 26 bifurcated and 14 aorto-uniiliac grafts). There was 1 conversion from eEVAR to open repair. Blood loss, operating time, duration of stay in intensive care, and duration of stay in the hospital were 948 ± 495.5 mL, 194 ± 12.7 min, 4.7 ± 1.26 days, and 14.5 ± 2.19 days, respectively. The 7-day, 30-day, and 12-month mortality rates were 15%, 17.5%, and 35%, respectively. Six patients required reintervention on follow-up, and 8 patients died during hospitalization. Cox regression analysis of survival found that hypotension (P = 0.001) and being >76 years of age (P = 0.002) were associated with reduced overall survival. Binary logistic regression found that hypotension is associated with increased 30-day mortality (P = 0.026).

CONCLUSIONS

This audit shows that the results of eEVAR in Hong Kong are comparable to international standards. In the endovascular era, this may be an attractive alternative to emergency open aneurysm repair.