Outcomes after Surgery among Patients Diagnosed with One or More Multi-Drug-Resistant Organisms

Background: Infections with multi-drug-resistant organisms (MDROs) may be difficult to treat and prolong patient hospitalization and recovery. Multiple MDRO coinfections may increase the complexity of clinical management. However, association between multiple MDROs and outcomes of patients who undergo surgery is unknown. Patients and Methods: We performed a retrospective, cross-sectional analysis of the 2016 National Inpatient Sample for identified by International Classification of Disease, 10th Revision Clinical Modification (ICD-10-CM) diagnosis codes associated with multi-drug-resistant organisms: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), multi-drug-resistant gram-negative bacilli, and Clostridioides difficile infection (CDI). Admitted patients with diagnosis codes for MDROs were cross-matched with codes for common general surgery procedures. Outcomes of interest included length of stay and mortality. Weighted univariable and multivariable analyses accounting for the survey methodology were performed. Results: Of 1,550,224 patients undergoing surgery in 2016, 39,065 (3%) admissions were diagnosed with an MDRO and 1,176 (0.1%) were associated with dual MDROs diagnoses. Patients diagnosed with one MDRO were hospitalized three times longer (17.3 days; 95% confidence interval [CI], 16.8-17.7) and patients diagnosed with two MDROs five times longer (31.6 days; 95% CI, 27.0-36.2; p < 0.0001) than undiagnosed patients (6.1 days; 95% CI, 6.1-6.1; all p < 0.0001). On multivariable analysis, the strongest predictor of mortality was a diagnosis of two MDRO infections (odds ratio [OR], 4.8; 95% CI, 3.16-7.21; p < 0.0001). The second strongest predictor was diagnosis of single MDRO infection (OR, 2.9; 95% CI, 2.64-3.20; p < 0.0001). Conclusion: Presence of an MDRO was associated with increased odds of mortality and length of stay in admitted surgical patients. Interventions to reduce MDRO infection among surgical patients may reduce hospital length of stay and mortality.

Prospective study of short-term quality-of-life after traumatic rib fractures

BACKGROUND

Postdischarge convalescence after traumatic rib fractures remains unclear. We hypothesized that patients with rib fractures, even as an isolated injury, have associated poor quality of life (QoL) after discharge.

METHODS

We prospectively enrolled adult patients at our level I trauma center with rib fractures between July 2019 and January 2020. We assessed QoL at 1 and 3 months after discharge using the Trauma-specific Quality-of-Life (T-QoL; 43-question survey evaluating five QoL domains on a 4-point Likert scale, where 4 indicates optimal and 1, worst QoL) and supplementary questionnaires. We used generalized estimating equations to assess T-QoL score trends over time and effect of age, sex, injury pattern, self-perceived injury severity, and Injury Severity Score.

RESULTS

We enrolled 139 patients (108 completed the first and 93 completed both surveys). Three months after discharge, 33% of patients were not working at preinjury capacity, and 7% were still using opioid analgesia. Suffering rib fractures mostly impacted recovery and resilience (T-QoL score, mean [robust standard error] at 1 month, 2.7 [0.1]; 3 months, 3.0[0.1]) and physical well-being domains (1 month, 2.5 [0.1]; 3 months, 2.9[0.1]). Quality of life improved over time across all domains. Compared with patients who perceived their injuries as mild/moderate, patients who perceived their injuries as severe/very severe reported worse T-QoL scores across all domains. In contrast, Injury Severity Score did not affect QoL. Patients 65 years or older (-0.6 [0.1]) and women (-0.6 [0.2]) reported worse functional engagement compared with those 65 years or older and men, respectively.

CONCLUSION

We found that patients with traumatic rib fractures experience suboptimal QoL after discharge. Quality of life improved over time, but even 3 months after discharge, patients reported challenges performing activities of daily living, slower-than-expected recovery, and not returning to work at preinjury capacity. Perception of injury severity had a large effect on QoL. Patients with rib fractures may benefit from close short-term follow-up.

LEVEL OF EVIDENCE

Prognostic and epidemiological, level III.

A multi-institutional study assessing general surgery faculty teaching evaluations

BACKGROUND

Resident evaluation of faculty teaching is an important metric in general surgery training, however considerable variability in faculty teaching evaluation (FE) instruments exists.

STUDY DESIGN

Twenty-two general surgery programs provided their FE and program demographics. Three clinical education experts performed blinded assessment of FEs, assessing adherence 2018 ACGME common program standards and if the FE was meaningful.

RESULTS

Number of questions per FE ranged from 1 to 29. The expert assessments demonstrated that no evaluation addressed all 5 ACGME standards. There were significant differences in the FEs effectiveness of assessing the 5 ACGME standards (p < 0.001), with teaching abilities and professionalism rated the highest and scholarly activities the lowest.

CONCLUSION

There was wide variation between programs regarding FEs development and adhered to ACGME standards. Faculty evaluation tools consistently built around all suggested ACGME standards may allow for a more accurate and useful assessment of faculty teaching abilities to target professional development.

Modified percutaneous tracheostomy in patients with COVID-19

Background

Patients hospitalized with COVID-19 are at risk of developing hypoxic respiratory failure and often require prolonged mechanical ventilation. Indication and timing to perform tracheostomy is controversial in patients with COVID-19.

Methods

This was a single-institution retrospective review of tracheostomies performed on patients admitted for COVID-19 between April 8, 2020 and August 1, 2020 using a modified percutaneous tracheostomy technique to minimize hypoxia and aerosolization.

Results

Twelve tracheostomies were performed for COVID-related respiratory failure. Median patient age was 54 years (range: 36–76) and 9 (75%) were male. Median time to tracheostomy was 17 days (range: 10–27), and 5 (42%) patients had failed attempts at extubation prior to tracheostomy. There were no intraprocedural complications, including hypoxia. Post-tracheostomy bleeding was noted in two patients. Eight (67%) patients have been discharged at the time of this study, and there were four patient deaths unrelated to tracheostomy placement. No healthcare worker transmissions resulted from participating in the tracheostomy procedure.

Conclusions

A modified percutaneous tracheostomy is feasible and can be safely performed in patients infected with COVID-19.

Level of evidence

Level V, case series.

Intravenous lidocaine as a non-opioid adjunct analgesic for traumatic rib fractures

INTRODUCTION

Pain management is the pillar of caring for patients with traumatic rib fractures. Intravenous lidocaine (IVL) is a well-established non-opioid analgesic for post-operative pain, yet its efficacy has yet to be investigated in trauma patients. We hypothesized that IVL is associated with decreased inpatient opioid requirements among patients with rib fractures.

METHODS

We retrospectively evaluated adult patients presenting to our Level 1 trauma center with isolated chest wall injuries. After 1:1 propensity score matching patients who received vs did not receive IVL, we compared the two groups' average daily opioid use, opioid use in the last 24 hours of admission, and pain scores during admissions hours 24-48. We performed multivariable linear regression for these outcomes (with sensitivity analysis for the opioid use outcomes), adjusting for age as a moderating factor and controlling for hospital length of stay and injury severity.

RESULTS

We identified 534 patients, among whom 226 received IVL. Those who received IVL were older and had more serious injury. Compared to propensity-score matched patients who did not receive IVL, patients who received IVL had similar average daily opioid use and pain scores, but 40% lower opioid use during the last 24 hours of admission (p = 0.002). Multivariable regression-with and without sensitivity analysis-did not show an effect of IVL on any outcomes.

CONCLUSION

IVL was crudely associated with decreased opioid requirements in the last 24 hours of admission, the time period associated with opioid use at 90 days post-discharge. However, we did not observe beneficial effects of IVL on multivariable adjusted analyses; we are conducting a randomized control trial to further evaluate IVL's opioid-sparing effects for patients with rib fractures.

Evidenced-Based Practice Among Trainees: A Survey on Facial Trauma Wound Management

OBJECTIVE

Assess whether facial trauma wound care and antibiotic use recommendations are guided by evidence-based practice (EBP) or practice patterns, and investigate strategies to improve EBP adoption among surgical trainees.

DESIGN

We conducted a survey of all trainees who manage facial trauma (general surgery, emergency medicine, plastic surgery, otolaryngology) to assess clinical knowledge and sources of treatment recommendations. Clinical questions were based on Oxford Center for Evidence-Based Medicine Level 1 or 2 evidence. We measured internal validity of questions using Cronbach's α. Results were weight-adjusted for nonresponse and then analyzed using Welch t test and descriptive statistics.

STUDY SETTING

Stanford Hospital and Clinics, a Level I trauma center.

RESULTS

Response rate was 50.3% overall (78/155). For recommendations on facial trauma wound and antibiotic use, nonspecialty junior residents most frequently relied on their own senior or specialty residents (79.1%); nonspecialty senior residents relied on specialty residents (67.9%). Specialty junior residents most often relied on their own senior residents (51.0%), the majority of whom made recommendations based on their own knowledge (73.2%). Questions assessing EBP knowledge had Cronbach's α of 0.98; response accuracy was similar between specialty and nonspecialty residents (54.6% vs 55.5%, p = 0.96). When provided recommendations that conflict with EBP, both nonspecialty and specialty residents more frequently followed recommendations rather than EBP; junior residents reported doing so to avoid conflict with superiors. Total 92.6% of surveyed residents felt cross-departmental EBP guidelines would improve patient care.

CONCLUSIONS

Facial trauma wound care and antibiotic recommendations disseminate down seniority and from craniofacial specialty to nonspecialty residents, yet knowledge of EBP among senior specialty and nonspecialty residents was weak. EBP may be difficult to adopt in the absence of consensus society guidelines. To address this gap, we published a review of EBP for facial trauma and plan to update our trauma manual with cross-departmental guidelines to facilitate EBP adoption among trainees.

Splenectomy for benign and malignant hematologic pathology: Modern morbidity, mortality, and long-term outcomes

Background

The role of splenectomy to diagnose and treat hematologic disease continues to evolve. In this single-center retrospective review, we describe modern morbidity, mortality, and long-term outcomes associated with splenectomy for benign and malignant hematologic disorders.

Methods

We analyzed all nontrauma splenectomies performed for benign or malignant hematologic disorders from January 2009 to September 2018. Variables collected included demographics, preexisting comorbidities, laboratory results, intra- and postoperative features, and long-term follow-up. Outcomes of interest included postoperative complications, 30-day mortality, and overall mortality.

Results

We identified 161 patients who underwent splenectomy for hematologic disorders. Median age was 54 years (range 19–94), and 83 (52%) were female. Splenectomy was performed for 95 (59%) patients with benign hematologic disorders and for 66 (41%) with malignant conditions. Most splenectomies were laparoscopic (76%), followed by laparoscopic hand assisted (11%), open (8%), and laparoscopic converted to open (6%). Median follow-up was 761 days (interquartile range: 179–2025 days). Major complications occurred in 21 (13%) patients. Three (2%) patients died within 30 days; 16 (9%) died more than 30 days after operation, none from surgical complications, with median time to death of 438 days (interquartile range: 231–1497 days). Among malignant cases, only preoperative thrombocytopenia predicted death (odds ratio = 5.8, 95% confidence interval = 1.1–31.8, P = .04). For benign cases, increasing age was associated with inferior survival (odds ratio = 2.3, 95% confidence interval = 1.0–5.1, P = .05).

Conclusion

Splenectomy remains an important diagnostic and therapeutic option for patients with benign and malignant hematologic disorders and can be performed with a low complication rate. Despite considerable burden of comorbid disease in these patients, early postoperative mortality was uncommon.

Mortality After General Surgery Among Hospitalized Patients With Hematologic Malignancy

BACKGROUND

Hospitalized patients with hematologic malignancies (HMs) may require abdominal operations for complications of malignancy, treatment sequelae, or unrelated abdominal pathology. We determined predictors of mortality after emergency general surgery for patients with HM using national-level data.

MATERIALS AND METHODS

We analyzed the 2010-2014 National Inpatient Sample for International Classification of Disease, Ninth Revision, Clinical Modification codes for HM and abdominal operations, comparing adult patient encounters with abdominal operations with HM to those without HM. Multivariate logistic regression was performed to identify predictors of mortality.

RESULTS

Of the 7.9 million adult inpatient encounters where abdominal surgery was performed, 82,187 (1%) had concomitant diagnoses of HM. Mortality among patient encounters with HM was significantly higher than without HM (9.0% versus 2.0%; P < 0.0001). Patient encounters with HM and surgery and a diagnosis of acute abdominal pain had mortality rates as high as 41%. The median standardized risk ratio for death after the top 25 general surgery procedures was 2.9 (interquartile range: 2.2-3.8) among patients with HM. In adjusted analyses, odds of mortality among patients with HM undergoing surgery were increased by concomitant acute abdominal pain diagnosis (odds ratio [OR] = 2.6; P < 0.0001), coagulopathy (OR = 2.0; P < 0.0001), aplastic anemia (OR = 1.7; P < 0.0001), peripheral vascular disease (OR = 1.4; P = 0.001), and weight loss (OR = 1.3; P < 0.0001).

CONCLUSIONS

Although uncommon, surgery on patients with HM is associated with mortality rates nearly five times higher than the general surgical population. Patients with HM requiring surgical intervention may be at particularly high odds of death and postoperative complications.

Pulmonary contusions in patients with rib fractures: The need to better classify a common injury

BACKGROUND

Pulmonary contusions are common injuries. Computed tomography reveals vast contused lung volume spectrum, yet pulmonary contusions are defined dichotomously (unilateral vs bilateral). We assessed whether there is stepwise increased risk of pulmonary complications among patients without, with unilateral, and with bilateral pulmonary contusion.

METHODS

We identified adults admitted with rib fractures using the largest US inpatient database. After propensity-score-matching patients without vs with unilateral vs bilateral pulmonary contusions and adjusting for residual confounders, we compared risk for pneumonia, ventilator-associated pneumonia (VAP), respiratory failure, intubation, and mortality.

RESULTS

Among 148,140 encounters of adults with multiple rib fractures, 19% had concomitant pulmonary contusions. Matched patients with pulmonary contusions had increased risk of pneumonia 19% [95%CI:16-33%], respiratory failure 40% [95%CI: 31-50%], and intubation 46% [95%CI: 33-61%]. Delineation showed bilateral contusions, not unilateral contusions, attributed to increased risk of complications.

CONCLUSIONS

There is likely a correlation between contused lung volume and risk of pulmonary complications; dichotomously classifying pulmonary contusions is insufficient. Better understanding this correlation requires establishing the clinically significant contusion volume and a correspondingly refined classification system.

Understanding Health Care Utilization and Mortality After Emergency General Surgery in Patients With Underlying Liver Disease

BACKGROUND

Mortality and complications are not well defined nationally for emergency general surgery (EGS) patients presenting with underlying all-cause liver disease (LD).

STUDY DESIGN

We analyzed the 2012-2014 National Inpatient Sample for adults (aged ≥ 18 years) with a primary EGS diagnosis. Underlying LD included International Classification of Diseases, Ninth Revision, Clinical Modification codes for alcoholic and viral hepatitis, malignancy, congenital etiologies, and cirrhosis. The primary outcome was mortality; secondary outcomes included complications, operative intervention, and costs.

RESULTS

Of the 6.8 million EGS patients, 358 766 (5.3%) had underlying LD. 59.1% had cirrhosis, 6.7% had portal hypertension, and 13.7% had ascites. Compared with other EGS patients, EGS-LD patients had higher mean costs ($12 847 vs $10 234, P < .001). EGS-LD patients were less likely to have surgery (26.1% vs 37.0%, P < .001) but for those who did, mortality was higher (4.8% vs 1.8%, P < .001). Risk factors for mortality included ascites (adjusted odds ratio [aOR] = 2.68, P < .001), dialysis (aOR = 3.44, P < .001), sepsis (aOR = 8.97, P < .001), and respiratory failure requiring intubation (aOR = 10.40, P < .001). Odds of death increased in both surgical (aOR = 4.93, P < .001) and non-surgical EGS-LD patients (aOR = 2.56, P < .001).

CONCLUSIONS

Underlying all-cause LD among EGS patients is associated with increased in-hospital mortality, even in the absence of surgical intervention.

Placement of Surgical Feeding Tubes Among Patients With Severe Traumatic Brain Injury Requiring Exploratory Abdominal Surgery : Better Early Than Late

OBJECTIVES

The purpose of this study was to identify trauma patients who would benefit from surgical placement of an enteral feeding tube during their index abdominal trauma operation.

METHODS

We performed a retrospective analysis of all patients admitted to 2 level I trauma centers between January 2013 and February 2018 requiring urgent exploratory abdominal surgery.

RESULTS

Six-hundred and one patients required exploratory abdominal surgery within 24 hours of admission after trauma activation. Nineteen (3% of total) patients underwent placement of a feeding tube after their initial exploratory surgery. On multivariate analysis, an intracranial Abbreviated Injury Scale ≥4 (odds ratio [OR] = 9.24, 95% CI 1.09-78.26, P = .04) and a Glasgow Coma Scale ≤8 (OR = 4.39, 95% CI 1.38-13.95, P = .01) were associated with increased odds of requiring a feeding tube. All patients who required a feeding tube had an Injury Severity Score ≥15. While not statistically significant, patients with an open surgical feeding tube compared with interventional radiology/percutaneous endoscopic gastrostomy placement had lower median intensive care unit length of stay, fewer ventilator days, and shorter median total hospital length of stay.

CONCLUSIONS

Trauma patients with severe intracranial injury already requiring urgent exploratory abdominal surgery may benefit from early, concomitant placement of a feeding tube during the index abdominal operation, or at fascial closure.

Association of Coworker Reports About Unprofessional Behavior by Surgeons With Surgical Complications in Their Patients

Importance

For surgical teams, high reliability and optimal performance depend on effective communication, mutual respect, and continuous situational awareness. Surgeons who model unprofessional behaviors may undermine a culture of safety, threaten teamwork, and thereby increase the risk for medical errors and surgical complications.

Objective

To test the hypothesis that patients of surgeons with higher numbers of reports from coworkers about unprofessional behaviors are at greater risk for postoperative complications than patients whose surgeons generate fewer coworker reports.

Design, Setting, and Participants

This retrospective cohort study assessed data from 2 geographically diverse academic medical centers that participated in the National Surgical Quality Improvement Program (NSQIP) and recorded and acted on electronic reports of safety events from coworkers describing unprofessional behavior by surgeons. Patients included in the NSQIP database who underwent inpatient or outpatient operations at 1 of the 2 participating sites from January 1, 2012, through December 31, 2016, were eligible. Patients were excluded if they were younger than 18 years on the date of the operation or if the attending surgeon had less than 36 months of monitoring for coworker reports preceding the date of the operation. Data were analyzed from August 8, 2018, through April 9, 2019.

Exposures

Coworker reports about unprofessional behavior by the surgeon in the 36 months preceding the date of the operation.

Main Outcomes and Measures

Postoperative surgical or medical complications, as defined by the NSQIP, within 30 days of the operation.

Results

Among 13 653 patients in the cohort (54.0% [7368 ] female; mean [SD] age, 57 [16] years) who underwent operations performed by 202 surgeons (70.8% [143] male), 1583 (11.6%) experienced a complication, including 825 surgical (6.0%) and 1070 medical (7.8%) complications. Patients whose surgeons had more coworker reports were significantly more likely to experience any complication (0 reports, 954 of 8916 [10.7%]; ≥4 reports, 294 of 2087 [14.1%]; P < .001), any surgical complication (0 reports, 516 of 8916 [5.8%]; ≥4 reports, 159 of 2087 [7.6%]; P < .01), or any medical complication (0 reports, 634 of 8916 [7.1%]; ≥4 reports, 196 of 2087 [9.4%]; P < .001). The adjusted complication rate was 14.3% higher for patients whose surgeons had 1 to 3 reports and 11.9% higher for patients whose surgeons had 4 or more reports compared with patients whose surgeons had no coworker reports (P = .05).

Conclusions and Relevance

Patients whose surgeons had higher numbers of coworker reports about unprofessional behavior in the 36 months before the patient's operation appeared to be at increased risk of surgical and medical complications. These findings suggest that organizations interested in ensuring optimal patient outcomes should focus on addressing surgeons whose behavior toward other medical professionals may increase patients' risk for adverse outcomes.

Traumatic Injuries Due to Interpersonal and Domestic Violence in the United States

BACKGROUND

Domestic and intimate partner violence (DV) are under-reported causes of injury. We describe the health care utilization of DV patients, hypothesizing they are at increased risk of mortality.

METHODS

We queried the 2014 Nationwide Emergency Department Sample for adult patients (18 y and older) with a primary diagnosis of trauma. DV was abstracted using International Statistical Classification of Diseases, ninth Revision codes for partner or spouse intimate violence, abuse, or neglect. The primary outcome was mortality; secondary outcomes included admission rates and charges.

RESULTS

Among 14 million trauma patients, 654,356 (5.0%) had a diagnosis of DV. Compared with other trauma patients, DV patients were younger (34.6 versus 46.8 y, P < 0.001), more often male (69.5% versus 50.1%, P < 0.001), and more likely to be uninsured (31.5% versus 15.6%, P < 0.001). 9154 (1.4%) were injured because of intimate partner violence, of which 90.2% were female. Drug and alcohol abuse (22.2%), anxiety (1.8%), and depression (1.3%) were high among all DV trauma patients. DV emergency department charges were higher ($4462 versus $2,871, P < 0.001). In adjusted analyses, DV trauma patients had 2.1 higher odds of mortality (aOR: 2.31, P < 0.001). DV trauma patients were also associated with a $1516 increase in emergency department charges compared with non-DV trauma patients (95% CI: $1489-$1,542, P < 0.001).

CONCLUSIONS

Injuries related to all types of DV are emerging as a public health crisis among both genders. To mitigate under-reporting, it is important to identify at-risk patients and provide them with appropriate resources.

Impact of shelter-in-place order for COVID-19 on trauma activations: Santa Clara County, California, March 2020

Introduction

The shelter-in-place order for Santa Clara County, California on 16 March was the first of its kind in the USA. It was unknown what impact this order would have on trauma activations.

Methods

We performed a retrospective analysis of institutional trauma registries among the two American College of Surgeons Level 1 trauma centers serving Santa Clara County, California. Trauma activation volumes at the trauma centers from January to March 2020 were compared with month-matched historical cohorts from 2018 to 2019.

Results

Only 81 (3%) patients were trauma activations at the trauma centers in the 15 days after the shelter-in-place order went into effect on 16 March 2020, compared with 389 activations during the same time period in 2018 and 2019 (p<0.0001). There were no other statistically significant changes to the epidemiology of trauma activations. Only one trauma activation had a positive COVID-19 test.

Discussion

Overall trauma activations decreased 4.8-fold after the shelter-in-place order went into effect in Santa Clara County on 16 March 2020, with no other effect on the epidemiology of persons presenting after traumatic injury.

Conclusion

Shelter-in-place orders may reduce strain on healthcare systems by diminishing hospital admissions from trauma, in addition to reducing virus transmission.

Regionalization Patterns for Children with Serious Trauma in California (2005-2015): A Retrospective Cohort Study

OBJECTIVE

Trauma centers provide coordinated specialty care and have been demonstrated to save lives. Many states do not have a comprehensive statewide trauma system. Variable geography, resources, and population distributions present significant challenges to establishing an effective uniform system for pediatric trauma care. We aimed to identify patterns of primary (field) triage and transfer of serious pediatric trauma throughout California. We hypothesized that pediatric primary triage to trauma center care would be positively associated with younger age, increased injury severity, and local emergency medical service (EMS) regions with increased resources. We hypothesized that pediatric trauma transfer would be associated with younger age, increased injury severity, and rural regions with decreased resources. Methods: We conducted a retrospective cohort study of the California Office of Statewide Health Planning and Development emergency department and inpatient discharge data (2005-2015). All patients with serious injury, defined as Injury Severity Score (ISS) >9 were included. Demographic, injury, hospital, and regional characteristics such as distances between patient residence and destination hospitals were tabulated. Univariate and multinomial logit analyses were conducted to analyze individual, hospital, and regional characteristics associated with the outcomes of location of primary triage and transfer. Estimates were converted into predicted probabilities for ease of data interpretation. Results: Primary triage to was to either a pediatric trauma center (37.8%), adult level I/II trauma center (35.0%), adult level III/IV trauma center (1.9%), pediatric non-trauma hospital (3.4%), or an adult non-trauma hospital (21.9%).Younger age, private non-HMO insurance, motor vehicle mechanism, and rural areas were the major factors influencing primary triage to any trauma hospital. Younger age, private non-HMO insurance, higher ISS, fall mechanism, <200 bed hospital, and rural areas were the major factors influencing transfer from a non-trauma hospital to any trauma center. Conclusions: We demonstrate statewide primary triage and transfer patterns for pediatric trauma in a large and varied state. Specifically we identified previously unrecognized individual, hospital, and EMS system associations with pediatric trauma regionalization. Knowledge of these de facto trauma care access patterns has policy and process implications that could improve care for all injured children in need.

Generalized Dilation of the Visceral Microvasculature by Peritoneal Dialysis Solutions

Objectives

Conventional peritoneal dialysis solutions are vasoactive. This vasoactivity is attributed to hyperosmolality and lactate buffer system. This study was conducted to determine if the vasodilator property of commercial peritoneal dialysis solutions is a global phenomenon across microvascular levels, or if this vasodilation property is localized to certain vessel types in the small intestine.

Design

Experimental study in a standard laboratory facility.

Interventions

Hemodynamics of anesthetized rats were monitored while the terminal ileum was prepared for in vivo intravital microscopy. Vascular reactivity of inflow arterioles (A1), branching (A2), and arcade, as well as pre-mucosal (A3) arterioles was assessed after suffusion of the terminal ileum with a non-vasoactive solution or a commercial 4.25% glucose-based solution (Delflex; Fresenius USA, Ogden, Utah, USA). Vascular reactivity of three different level venules was also assessed. Maximum dilation response was obtained from sequential applications of the endothelial-dependent dilator, acetylcholine (10–5 mol/L), and the endothelial-independent nitric oxide donor, sodium nitroprusside (NTP; 10–4mol/L).

Results

Delflex induced an instant and sustained vasodilation that averaged 28.2% ± 2.4% of baseline diameter in five different-level arterioles, ranging in size between 7 μ and 100 μ. No significant vascular reactivity was observed in three different-level venules. Delflex increased intestinal A1 blood flow from baseline 568 ± 31 nL/second to 1049 ± 46 nL/sec ( F = 24.7, p < 0.001). Similarly, intestinal venous outflow increased to 435 ± 17 nL/sec from a baseline outflow of 253 ± 59 nL/sec ( F = 4.7, p < 0.05). Adjustment of the initial pH of Delflex from 5.5 to 7.4 resulted in similar microvascular responses before pH adjustment.

Conclusions

Ex vivo exposure of intestinal arterioles to conventional peritoneal dialysis solutions produces a sustained and generalized vasodilation. This vasoactivity is independent of arteriolar level and the pH of the solution. Dialysis solution-mediated vasodilation is associated with doubling of A1 intestinal arteriolar blood flow. Addition of NTP at an apparent clinical dose does not appear to produce any further significant arteriolar dilation than that induced by dialysis solution alone. Experimental data that estimate the exchange vessel surface area per unit volume of tissue will be required to make a correlation with permeability in order to extrapolate our findings to clinical in vivo conditions.