A Review of Bicarbonate Use in Common Clinical Scenarios.

BACKGROUND: The use of sodium bicarbonate to treat metabolic acidosis is intuitive, yet data suggest that not all patients benefit from this therapy. OBJECTIVE: In this narrative review, we describe the physiology behind commonly encountered nontoxicologic causes of metabolic acidosis, highlight potential harm from the indiscriminate administration of sodium bicarbonate in certain scenarios, and provide evidence-based recommendations to assist emergency physicians in the rational use of sodium bicarbonate. DISCUSSION: Sodium bicarbonate can be administered as a hypertonic push, as a resuscitation fluid, or as an infusion. Lactic acidosis and cardiac arrest are two common scenarios where there is limited benefit to routine use of sodium bicarbonate, although certain circumstances, such as patients with concomitant acute kidney injury and lactic acidosis may benefit from sodium bicarbonate. Patients with cardiac arrest secondary to sodium channel blockade or hyperkalemia also benefit from sodium bicarbonate therapy. Recent data suggest that the use of sodium bicarbonate in diabetic ketoacidosis does not confer improved patient outcomes and may cause harm in pediatric patients. Available evidence suggests that alkalinization of urine in rhabdomyolysis does not improve patient-centered outcomes. Finally, patients with a nongap acidosis benefit from sodium bicarbonate supplementation. CONCLUSIONS: Empiric use of sodium bicarbonate in patients with nontoxicologic causes of metabolic acidosis is not warranted and likely does not improve patient-centered outcomes, except in select scenarios. Emergency physicians should reserve use of this medication to conditions with clear benefit to patients.

Elexacaftor - Tezacaftor - Ivacaftor treatment improves systemic infection parameters and Pseudomonas aeruginosa colonization rate in patients with cystic fibrosis a monocentric observational study.

Background & aims: The CFTR-modulating therapy Elexaftor - Tezacaftor - Ivacaftor (ETI) has been widely prescribed since its approval in 2020 in the European Union. The aim of this study was to methodically evaluate the effects of an ETI treatment on clinical, biochemical data and Pseudomonas colonization in order to demonstrate its efficacy. Methods: This prospective monocentric study comprised 69 patients diagnosed with cystic fibrosis aged at least 12 years and treated with ETI between September 2020 and November 2021. Clinical and laboratory data of each patient and study visit were collected before and after 24 weeks of ETI treatment. Follow-up status of Pseudomonas aeruginosa (PsA) colonization was assessed after one year of therapy by regularly determined sputum or throat swab samples. Results: Marked improvements biochemical markers of systemic inflammation as white blood cell count, levels of immunoglobulins A, G and M and albumin within 24 weeks of therapy were observed. ETI treatment proved to be effective as seen by amelioration of lung function and sweat chloride concentration. Assessment of PsA colonization status revealed a conversion from a positive to negative detection in 36% of the cases after one year of therapy. Conclusions: ETI treatment effectively improves systemic inflammation parameters and shows promising results in PsA status conversion.

Increase of liver stiffness and altered bile acid metabolism after triple CFTR modulator initiation in children and young adults with cystic fibrosis.

BACKGROUND: Novel cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies (elexacaftor/tezacaftor/ivacaftor-ETI) promise clinically significant and sustained improvements for patients with cystic fibrosis (CF). In this study, we investigated the impact of ETI therapy on liver stiffness and bile acid metabolism in a cohort of children and young adults with CF. METHODS: A prospective observational study (NCT05576324) was conducted from September 2020 to November 2021 enrolling CF patients naive to ETI. Standard laboratory chemistry, sweat test, lung function, share wave velocity (SWV) derived by acoustic radiation force impulse imaging (ARFI) and serum bile acid profiles were assessed before and 6 months after induction of ETI therapy. RESULTS: A total of 20 patients (10 aged <20 years) completed the study. While lung function and BMI improved after ETI therapy, ARFI SWV increased in CF patients <20 years of age (from 1.27 to 1.43 m/s, p = 0.023). Bile acid (BA) profiles revealed a decrease in unconjugated (5.75 vs 1.46, p = 0.007) and increase in glycine-conjugated derivatives (GCDCA) (4.79 vs 6.64 p = 0.016). There was a positive correlation between ARFI SWV values and GCDCA (r = 0.80, p < 0.0001). Glycine-conjugated BA provided high diagnostic accuracy to predict increased ARFI measurements (AUC 0.90) and clinical (Colombo) CFLD grading (AUC 0.97). CONCLUSIONS: ARFI SWV and bile acid profiles provide evidence for early increase in liver stiffness and altered bile acid metabolism in young CF patients after initiation of ETI and may serve as synergistic measures for detection of hepatic complications during ETI therapy.

The Knowledge Gap: Mentorship in Emergency Medicine Residency.

STUDY OBJECTIVE: Studies of mentorship in emergency medicine show that mentored residents are twice as likely to describe their career preparation as excellent as compared to nonmentored peers. There has been significant interest in the mentor-mentee relationship in medicine; however, there is minimal guidance and published literature specific to emergency medicine residents. METHODS: In this narrative review, we described the emergency medicine mentor-mentee relationship, discussed alternatives to the traditional dyadic model, and highlighted current barriers to effective mentorship. We conducted a structured literature review to identify relevant published articles regarding the mentoring of emergency medicine residents. Additional studies from general mentoring literature were included based on relevancy. RESULTS: We identified 39 studies in emergency medicine literature based on our search criteria. Additional studies from general medicine literature were included based on relevancy to this review. Based on the limited available literature, we recommend maximizing the resident mentoring relationship by developing formal mentoring programs, supporting the advancement of women and underrepresented minority mentors, and moving toward team mentoring, including peer, near-peer, and collaborative mentorship. The development of a mentoring network is a logical strategy for residents to work with a diverse group of individuals to maximize benefits in multiple areas. CONCLUSION: Alternative approaches to the traditional and hierarchal dyadic mentoring style (eg, team mentoring) are effective methods that residencies may promote to increase effective mentoring. Future efforts in mentoring emergency medicine residents emphasize these strategies, which are increasingly beneficial given the constraints and use of technology highlighted by the COVID-19 pandemic.

Envenomation by the Green Bush Viper Atheris squamigera.

The Green Bush Viper, Atheris squamigera, is native to West and Central Africa and has few well reported envenomations. Bite victims experience dizziness, nausea, headache, regional lymphadenopathy, and localized edema. Most reports also detail severe effects including thrombocytopenia, coagulopathy, hemolysis, hemorrhage, or renal failure. Fatalities are reported, but poorly described. There is no specific antivenom for A. squamigera, but non-species specific antivenom has been reported helpful in several cases. We report the case of a 36-year-old woman who was bitten by a green bush viper and was treated with several non-species specific antivenoms. There were no complications to antivenom administration and the patient experienced a milder envenomation than detailed in previous reports.

Reduction in Hospital Transfers at a US COVID-19 Alternate Care Site: Maintaining Surge Capacity Support in Imperial County, California.

OBJECTIVE: The transfer rate for patients from an Alternate Care Site (ACS) back to a hospital may serve as a metric of appropriate patient selection and the ability of an ACS to treat moderate to severely ill patients accepted from overwhelmed health-care systems. During the coronavirus infectious disease 2019 (COVID-19) pandemic, hospitals worldwide experienced acute surges of patients presenting with acute respiratory failure. METHODS: An ACS in Imperial County, California was re-established in November 2020 to help decompress 2 local hospitals experiencing surges of COVID-19 cases. The patients treated often had multiple comorbid illnesses and required a median supplemental oxygen of 3 L/min (LPM) on admission. Numerous interventions were initiated during a 2-wk period to improve clinical care delivery. RESULTS: The objectives of this retrospective observational study are to evaluate the impact of these clinical and staff interventions at an ACS on the transfer rate and to provide issues to consider for future ACS sites managing COVID-19 patients. CONCLUSIONS: The data suggest that continuous, real-time process-improvement interventions helped reduce the transfer rate back to hospitals from 36.7% to 14.5% and that an ACS is a viable option for managing symptomatic COVID-19 positive patients requiring hospital-level care when hospitals are overburdened.

Novel Use of 3-Point Genicular Nerve Block for Acute Knee Pain in the Emergency Department.

BACKGROUND: Ultrasound-guided genicular nerve blocks (GNBs) in the emergency department (ED) have easily identifiable anatomic targets and offer an opportunity to provide safe, effective, motor-sparing analgesia for acute knee pain. Case Report A 68-year-old woman presented with acute, 8/10 right knee pain due to an isolated right lateral tibial plateau fracture. After informed consent and with the ultrasound in the sagittal plane, the superior lateral (SLGN), superior medial (SMGN), and inferior medial (IMGN) genicular nerves were identified at the junction of their respective femoral or tibial epicondyle and femoral or tibial epiphysis. The skin was anesthetized and an echogenic needle was inserted under ultrasound guidance to inject 1.0 mL of 0.5% bupivacaine around the right SLGN, SMGN, and IMGN. Approximately 30 minutes after the GNBs, the patient reported 0/10 pain at rest and 1/10 pain with movement. She did not require opioids during her ED visit or upon discharge. Why Should an Emergency Physician Be Aware of This? GNBs show promise as a useful tool to provide acute and medium-term motor-sparing analgesia in a patient with acute knee pain. GNBs have easy-to-recognize anatomic targets on ultrasound and may be a suitable adjunct or alternative to a multimodal pain regimen in the emergency department.

Impact of supplemental training programs on improving medical students' confidence in providing diabetes self-management education and support.

BACKGROUND/PURPOSE: The purpose of this study was to evaluate the effectiveness of supplemental diabetes-related training modalities and volunteer activities in increasing first-year medical students' knowledge/comfort in providing diabetes self-management education and support (DSMES) to patients. METHODS: A group of medical students developed supplemental diabetes-related training/volunteer programs. The training modalities included an optional 7-session interprofessionally taught Diabetes Enrichment Elective and a 3-hour endocrinologist-led training session intended to prepare students for involvement in an inpatient DSMES volunteer program. The volunteer program provided the students with the opportunity to provide DSMES to patients with diabetes admitted to an academic medical center. Those participating in any of the stated programs were compared to those with no such training regarding confidence in providing DSMES using an optional online survey. The results were analyzed by using Mann-Whitney U test and descriptive analyses. RESULTS: A total of 18 first-year medical students responded to the optional survey with a response rate of ~30% (10 of 33) among participants in any training/volunteer program. First-year medical students who attended any of the offered optional programs had statistically significant higher comfort level in 4 of the 6 areas assessed regarding providing DSMES compared with those with no such training (p<0.05), with medium to large effect size (r=0.48-0.59). CONCLUSION: This study suggests that the supplemental preclerkship diabetes-specific training modalities/volunteer programs can provide benefit in providing medical students with practical knowledge while improving their confidence in providing DSMES to patients with diabetes.

Low-profile versus standard-profile multibranched thoracoabdominal aortic stent grafts.

OBJECTIVE: This study compared midterm results using low-profile stent grafts (LPSGs; 18F) and standard-profile stent grafts (SPSGs; 22F-24F) for endovascular pararenal and thoracoabdominal aortic aneurysm (TAAA) repair. METHODS: From July 2005 to March 2015, 134 asymptomatic patients underwent endovascular repair of a pararenal or TAAA using multibranched aortic stent grafts. In March 2011, we started using a LPSG with nitinol stents and thin-walled polyester fabric. Prospectively collected data on operative repair, complications, and outcomes were compared between the two groups. RESULTS: LPSGs were used in 37 patients (8 women [21.6%]; mean ± standard deviation age, 72.5 ± 8 years) and SPSGs in 97 patients (25 [26%] women; mean age, 73 ± 8 years). Medical comorbidities, aneurysm size, and aneurysm extent were similar in the LPSG and SPSG groups. Mean follow-up time was longer in the SPSG group (3.1 ± 2 years) than in the LPSG group (1.3 ± 0.9 years; P < .001). Operative time, renal failure, stroke, myocardial infarction, and perioperative death were not significantly different between the two groups (P > .05). Aneurysm-related death, rupture, stent graft migration, type I or III endoleaks, aneurysm enlargement >5 mm, branch vessel occlusion, and reintervention rates were similar between the two groups (P > .05). However, the combined outcome of conduit use or access artery injury occurred at a lower rate in the LPSG group than in the SPSG group (16% vs 36%; P = .03). Women experienced significantly higher rates of conduit use and access artery injury than men after repair with SPSGs (64% vs 26%, respectively; P = .001) but similar rates after repair with the LPSG (25% vs 14%, respectively; P = .45). CONCLUSIONS: LPSGs had similar safety profile and midterm outcomes compared with the SPSGs for treatment of pararenal and TAAA. The substitution of LPSGs for SPSGs lowered the number of patients who required conduit insertion to avoid access artery injury, especially in women, thereby reducing an otherwise striking gender difference.

Standard off-the-shelf versus custom-made multibranched thoracoabdominal aortic stent grafts.

OBJECTIVE: The complex aortic branch anatomy in thoracoabdominal aortic aneurysms (TAAAs) and pararenal aortic aneurysms (PRAAs) presents a challenge for endovascular repair. The multibranched endovascular device has durable midterm results with use of a custom branch stent graft (CSG) configuration. The midterm results with use of the standard branch stent graft (SSG) configuration are unknown, but it has the advantage of off-the-shelf technology. The goal of this study was to compare the midterm outcomes of CSG and SSG multibranched endovascular devices. METHODS: From July 2005 to September 2014, 133 patients underwent elective endovascular repair of TAAA and PRAA in a prospective trial. Beginning in December 2008, SSGs were used in those with suitable anatomy. RESULTS: Fifty patients (mean age, 71 ± 7 years; 11 women [22%]) were treated using SSGs, and 83 patients (mean age, 74 ± 9 years; 22 women [26.5%]) underwent repair using CSGs. The SSG and CSG groups were similar with regard to aneurysm size, aneurysm extent, and medical comorbidities, with the sole exception of lung disease, which was more common in the SSG group. All stent grafts were deployed as intended, with no conversions to open repair. Mean ± standard deviation follow-up (days) was 694 ± 525 for the SSG group and 942 ± 764 for the CSG group (P = .045). There were no significant differences in aneurysm-related death, renal failure requiring dialysis, stroke, endoleak, visceral or renal branch occlusion, lower extremity weakness, or reintervention (P > .05 for each). The volume of contrast material was significantly lower in those with SSGs compared with CSGs (P = .016), but there were no significant differences in operative or fluoroscopy times. Time to treatment (days from consent to surgery) was significantly lower in SSG patients compared with CSG patients (P = .01). CONCLUSIONS: For patients with suitable anatomy, the use of SSGs for TAAA and PRAA repair results in significantly shorter wait times to surgery and is as safe, effective, and durable in the midterm compared with CSGs.

Lower extremity weakness after endovascular aneurysm repair with multibranched thoracoabdominal stent grafts.

OBJECTIVE: We conducted our study to describe the incidence, presentation, management, risk factors, and outcomes of lower extremity weakness (LEW) after elective endovascular aneurysm repair with multibranched thoracoabdominal stent grafts. METHODS: Excluding symptomatic patients and those with aortic dissection, between July 2005 and October 2013, 116 patients with aortic aneurysms were treated in a prospective, single-center trial of multibranched endovascular aneurysm repair. LEW that resolved within 30 days of operation was classified as transient. Persistent LEW was defined as inability to walk or stand 30 days after surgery. Perioperative spinal cord protection measures included bypass as needed to maintain flow to the subclavian and internal iliac arteries, cerebrospinal fluid drainage, and permissive hypertension. RESULTS: Postoperative LEW occurred in 24 of 116 patients (20.6%). In 15 (12.9%), LEW was transient with full recovery. Nine patients (7.7%) had persistent LEW, three with paraparesis and six with paraplegia. Five of 24 patients (21%) awoke from anesthesia with LEW. Symptoms of LEW developed within 72 hours of operation in 14 of 24 (58%). Late-onset LEW (≥72 hours postoperatively) always occurred in the presence of a precipitating hypotensive event (5 of 24; 21%). Univariate analysis showed no association between LEW and Crawford type, staged repair, aneurysm extent, or postoperative endoleak. Baseline glomerular filtration rate <30 mL/min/1.73 m(2) (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.2-14.6; P = .03), fluoroscopy time >190 minutes (OR, 3.6; 95% CI, 1.0-12.7; P = .04), and sustained hypotension (OR, 2.9; 95% CI, 1.1-7.7; P = .04) were identified as independent risk factors for LEW in multivariate analysis. CONCLUSIONS: Most episodes of LEW after multibranched endovascular aneurysm repair are transient and do not occur in the operating room. Adjunctive strategies to maintain spinal perfusion, including cerebrospinal fluid drainage and permissive hypertension, may help prevent permanent LEW.

Visceral branch occlusion following aneurysm repair using multibranched thoracoabdominal stent-grafts.

PURPOSE: To identify risk factors for late-occurring branch occlusion following multibranched endovascular repair of thoracoabdominal and pararenal aortic aneurysm. METHOD: Out of 120 patients who underwent multibranched endovascular aneurysm repair between September 2005 and May 2013, 100 (78 men; mean age 72.4 ± 7.4 years) met the criteria for inclusion in the current retrospective analysis. Demographic data were gleaned from a prospectively maintained database. Mean aneurysm diameter was 66.7 ± 11.7 mm. Multiplanar reconstructions of postoperative computed tomographic angiography were used to measure 6 parameters of renal branch morphology. RESULTS: All 100 patients had undergone successful placement of multibranched aortic stent-grafts with a total of 95 celiac branches, 100 superior mesenteric artery (SMA) branches, and 187 renal branches. During a mean follow-up of 25.6 months, there were no stent fractures or stent separations, no SMA occlusions, and only 2 (2.1%) celiac artery occlusions, neither of which required reintervention. In contrast, there were 18 (9.6%) renal branch occlusions in 16 patients, all men (p=0.02). Patients with renal branch occlusions were significantly more likely to have a history of myocardial infarction (p=0.004). The mean renal artery length was significantly greater in the occlusion group compared to the non-occlusion group (47.5 ± 13.6 vs. 39.4 ± 14.2, p=0.03). No other aspect of branch morphology was significantly different between the occlusion and non-occlusion groups. CONCLUSION: Renal branch occlusion was by far the commonest late failure mode after multibranched endovascular aneurysm repair. The current study provides no basis for a change in patient selection or stent-graft design, only a change in the components used to construct renal branches. It is too early to tell the effect this will have.

Assessing the anatomic applicability of the multibranched endovascular repair of thoracoabdominal aortic aneurysm technique.

BACKGROUND: Multibranched endovascular aneurysm repair (MBEVAR) has the potential to lower the morbidity and mortality rates of thoracoabdominal aneurysm repair, but the applicability of the technique is unknown. Our aim was to estimate the prevalence of anatomic suitability for MBEVAR. METHODS: Retrospective review of patients referred for a prospective trial of MBEVAR between November 2005 and July 2012. Anatomic suitability was assessed on three-dimensional computed tomography scan reconstructions according to the current criteria for a custom-made stent graft or a fixed, off-the-shelf stent graft in both standard (22F) and low-profile (18F) delivery systems. RESULTS: A total of 250 contrast-enhanced computed tomography scans were reviewed, 49 of which were excluded due to inadequate aneurysm size. Of 201 candidates for repair, 149 (74%) were men and 86 (43%) had Crawford classification type IV/paravisceral aneurysms; 109 (58%) were anatomically suitable for a single-stage repair with a custom-made, low-profile stent graft. Another 58 (29%) could have been made suitable for MBEVAR with an adjunct procedure, including angiogram with visceral or renal artery stenting (n = 23), carotid-subclavian bypass (n = 5), or iliac bypass for device insertion (n = 17), or to preserve internal iliac artery flow because of an iliac aneurysm (n = 9), or dissection (n = 8). There was no association between suitability and gender, aneurysm diameter, or type. However, women were significantly more likely to need a conduit or low-profile device (P = .003). Patients with type B aortic dissections were significantly less likely to have anatomy suitable for repair (P = .035) and more likely to require a multistage repair. Thirty-four patients would have been unsuitable for repair because of renal artery anatomy (n = 14), visceral artery anatomy (n = 4), lack of a proximal landing zone due to an arch aneurysm (n = 7), or inadequate access arteries (n = 9). The low-profile device increased the number of patients who would have been suitable for a single-stage repair by 16. The off-the-shelf graft has the advantage of a faster assessment-to-treatment time, but only 64 patients would have been suitable for a single-stage repair and another 30 could have been made suitable with an adjunct procedure. CONCLUSIONS: Most patients would have been suitable or could have been made suitable for a thoracoabdominal stent graft using current anatomic criteria. The applicability of MBEVAR will continue to change as the experience with the technique grows and devices evolve, as evidenced by the potential reduction in iliac bypasses after the introduction of a low-profile device and the ability to treat symptomatic or urgent patients with the off-the-shelf device.

Efficacy and durability of endovascular thoracoabdominal aortic aneurysm repair using the caudally directed cuff technique.

OBJECTIVE: This study determined early and intermediate results of multibranched endovascular thoracoabdominal (TAAA) and pararenal aortic aneurysm (PRAA) repair using a uniform operative technique. METHODS: Eighty-one patients (mean age, 73 ± 8 years, 19 [23.5%] women) underwent endovascular TAAA repair in a prospective trial using self-expanding covered stents connecting axially oriented, caudally directed cuffs to target aortic branches. Mean aneurysm diameter was 67 ± 10 mm. Thirty-nine TAAA (48.1%) were Crawford type II, III, or V; 42 (51.9%) were type IV or pararenal. Thirty-three procedures (40.7%) were staged. The insertion approach was femoral for aortic components and brachial for branch components. Follow-up assessments were performed at 1, 6, and 12 months, and yearly thereafter. RESULTS: All devices (n = 81) and branches (n = 306) were successfully inserted and deployed, with no conversions to open repair. Overall mortality was 6.2% (n = 5), including three perioperative (3.7%) and two late treatment-related deaths (2.5%). Permanent paraplegia occurred in three patients (3.7%), and transient paraplegia/paraparesis occurred in 16 (19.8%). Four patients (4.9%) required dialysis postoperatively, three permanently and one transiently. Women accounted for 67% of the paraplegia, 75% of the perioperative dialysis, and 60% of the perioperative or treatment-related deaths. During a mean follow-up of 21.2 months, no aneurysms ruptured, but four (4.9%) enlarged: two were successfully treated, one was unsuccessfully treated, and one was not treated. No late onset spinal cord ischemia symptoms developed. Of the five patients starting dialysis during follow-up, two resulted from renal branch occlusion. Sixteen branches occluded (nine renal, two celiac) or developed stenoses (four renal, one superior mesenteric artery), requiring stenting. Primary patency was 94.8%, and primary-assisted patency was 95.1%. Thirty-two patients (39.5%) underwent 42 reinterventions. Of 25 early reinterventions (≤ 45 days), 10 were to treat access or insertion complications, and 5 were for endoleak. Of 17 late reinterventions, eight were for endoleak and five were for branch stenosis/occlusion. New endoleaks developed in two patients during follow-up. Overall, 73 of 81 patients (90.1%) were treated without procedure-related death, dialysis, paralysis, aneurysm rupture, or conversion to open repair. CONCLUSIONS: Total endovascular TAAA/PRAA repair using caudally directed cuffs is safe, effective, and durable in the intermediate term. The most common form of late failure, renal artery occlusion, rarely had a clinically significant consequence (dialysis). The trend toward worse outcome in women needs further study.