Online medical education: A student survey

BACKGROUND

During COVID-19, medical schools transitioned to online learning as an emergency response to deliver their education programmes. This multi-country study compared the methods by which medical schools worldwide restructured the delivery of medical education during the pandemic.

METHODS

This multi-country, cross-sectional study was performed using an internet-based survey distributed to medical students in multiple languages in November 2020.

RESULTS

A total of 1,746 responses were received from 79 countries. Most respondents reported that their institution stopped in-person lectures, ranging from 74% in low-income countries (LICs) to 93% in upper-middle-income countries. While only 36% of respondents reported that their medical school used online learning before the pandemic, 93% reported using online learning after the pandemic started. Of students enrolled in clinical rotations, 89% reported that their rotations were paused during the pandemic. Online learning replaced in-person clinical rotations for 32% of respondents from LICs versus 55% from high-income countries (HICs). Forty-three per cent of students from LICs reported that their internet connection was insufficient for online learning, compared to 11% in HICs.

CONCLUSIONS

The transition to online learning due to COVID-19 impacted medical education worldwide. However, this impact varied among countries of different income levels, with students from LICs and lower middle income countries facing greater challenges in accessing online medical education opportunities while in-person learning was halted. Specific policies and resources are needed to ensure equitable access to online learning for medical students in all countries, regardless of socioeconomic status.

Who gets burned in Brazil?

Burns are preventable injuries that still represent a relevant public health issue. The identification of risk factors might contribute to the development of specific preventive strategies. Data of patients admitted at the Hospital due to acute burn injuries from May 2017 to December 2019, was extracted manually from medical records. The population was analyzed descriptively, and differences between groups were tested using the appropriate statistical test. The study population consisted of 370 patients with burns admitted to the Hospital burn unit during the study period. The majority of the patients were males (257/370, 70%), median age was 33 (IQR:18-43), median TBSA% was 13 (IQR 6.35-21.5 and range 0-87.5%), and 54% of patients had full thickness burns (n=179). Children younger than 13 years old represented 17% of the study population (n=63), 60% of them were boys (n= 38), and scalds was the predominant mechanism of burn injury (n= 45). No children died, however 10% of adults did (n= 31). Self-inflicted burns were observed in 16 adults (5%), of whom 6 (38%) died during admission, however self-inflicted burns were not observed in children. Psychiatric disorders and substance misuse were frequent in this subgroup. White adults male from urban areas who had not completed primary school degree were the major risk group for burns. Smoking and alcohol misuse were the most frequent comorbidities. Accidental domestic flame burns were the predominant injuries in the adult population and scalds in the pediatric.

Gender-Based Discrimination Among Medical Students: A Cross-Sectional Study in Brazil

INTRODUCTION

Gender-based discrimination (GBD) creates a hostile environment during medical school, affecting students' personal life and academic performance. Little is known about how GBD affects the over 204,000 medical students in Brazil. This study aims to explore the patterns of GBD experienced by medical students in Brazil.

METHODS

This is a cross-sectional study using an anonymous, Portuguese survey disseminated in June 2021 among Brazilian medical students. The survey was composed of 24 questions to collect data on GBD during medical school, formal methods for reporting GBD, and possible solutions for GBD.

RESULTS

Of 953 responses, 748 (78%) were cisgender women, 194 (20%) were cisgender men, and 11 (1%) were from gender minorities. 65% (616/942) of respondents reported experiencing GBD during medical school. Women students experienced GBD more than men (77% versus 22%; P < 0.001). On comparing GBD perpetrator roles, both women (82%, 470/574) and men (64%, 27/42) reported the highest rate of GBD by faculty members. The occurrence of GBD by location differed between women and men. Only 12% (115/953) of respondents reported knowing their institution had a reporting mechanism for GBD.

CONCLUSIONS

Most respondents experienced GBD during medical school. Cisgender women experienced GBD more than cisgender men. Perpetrators and location of GBD differed for men and women. Finally, an alarming majority of students did not know how to formally report GBD in their schools. It is imperative to adopt broad policy changes to diminish the rate of GBD and its a consequential burden on medical students.

Thoracoscopy versus thoracotomy for esophageal atresia and tracheoesophageal fistula: Outcomes from the Midwest Pediatric Surgery Consortium

BACKGROUND/PURPOSE

Controversy persists regarding the ideal surgical approach for repair of esophageal atresia with tracheoesophageal fistula (EA/TEF). We examined complications and outcomes of infants undergoing thoracoscopy and thoracotomy for repair of Type C EA/TEF using propensity score-based overlap weights to minimize the effects of selection bias.

METHODS

Secondary analysis of two databases from multicenter retrospective and prospective studies examining outcomes of infants with proximal EA and distal TEF who underwent repair at 11 institutions was performed based on surgical approach. Regression analysis using propensity score-based overlap weights was utilized to evaluate outcomes of patients undergoing thoracotomy or thoracoscopy for Type C EA/TEF repair.

RESULTS

Of 504 patients included, 448 (89%) underwent thoracotomy and 56 (11%) thoracoscopy. Patients undergoing thoracoscopy were more likely to be full term (37.9 vs. 36.3 weeks estimated gestational age, p < 0.001), have a higher weight at operative repair (2.9 vs. 2.6 kg, p < 0.001), and less likely to have congenital heart disease (16% vs. 39%, p < 0.001). Postoperative stricture rate did not differ by approach, 29 (52%) thoracoscopy and 198 (44%) thoracotomy (p = 0.42). Similarly, there was no significant difference in time from surgery to stricture formation (p > 0.26). Regression analysis using propensity score-based overlap weighting found no significant difference in the odds of vocal cord paresis or paralysis (OR 1.087 p = 0.885), odds of anastomotic leak (OR 1.683 p = 0.123), the hazard of time to anastomotic stricture (HR 1.204 p = 0.378), or the number of dilations (IRR 1.182 p = 0.519) between thoracoscopy and thoracotomy.

CONCLUSION

Infants undergoing thoracoscopic repair of Type C EA/TEF are more commonly full term, with higher weight at repair, and without congenital heart disease as compared to infants repaired via thoracotomy. Utilizing propensity score-based overlap weighting to minimize the effects of selection bias, we found no significant difference in complications based on surgical approach. However, our study may be underpowered to detect such outcome differences owing to the small number of infants undergoing thoracoscopic repair.

LEVEL OF EVIDENCE

Level III.

Surgical capacity assessment in the state of Amazonas using the surgical assessment tool. Cross-sectional study

OBJECTIVE

Brazil is a country with universal health coverage, yet access to surgery among remote rural populations remains understudied. This study assesses surgical care capacity among hospitals providing care for the rural populations in the Amazonas state of Brazil through in-depth facility assessments.

METHODS

a stratified randomized cross-sectional evaluation of hospitals that self-report providing surgical care in Amazonas was conducted from July 2016 to March 2017. The Surgical Assessment Tool (SAT) developed by the World Health Organization and the Program in Global Surgery and Social Change at Harvard Medical School was administered at remote hospitals, including a retrospective review of medical records and operative logbooks.

RESULTS

18 hospitals were surveyed. Three hospitals (16.6%) had no operating rooms and 12 (66%) had 1-2 operating rooms. 14 hospitals (77.8%) reported monitoring by pulse oximetry was always present and six hospitals (33%) never have a professional anesthesiologist available. Inhaled general anesthesia was available in 12 hospitals (66.7%), but 77.8% did not have any mechanical ventilation device. An average of 257 procedures per 100,000 were performed. 10 hospitals (55.6%) do not have a specific post-anesthesia care unit. For the regions covered by the 18 hospitals, with a population of 497,492 inhabitants, the average surgeon, anesthetist, obstetric workforce density was 6.4.

CONCLUSION

populations living in rural areas in Brazil face significant disparities in access to surgical care, despite the presence of universal health coverage. Development of a state plan for the implementation of surgery is necessary to ensure access to surgical care for rural populations.

Acid suppression duration does not alter anastomotic stricture rates after esophageal atresia with distal tracheoesophageal fistula repair: A prospective multi-institutional cohort study

INTRODUCTION

Anastomotic stricture is the most common complication after esophageal atresia (EA) repair. We sought to determine if postoperative acid suppression is associated with reduced stricture formation.

METHODS

A prospective, multi-institutional cohort study of infants undergoing primary EA repair from 2016 to 2020 was performed. Landmark analysis and multivariate Cox regression were used to explore if initial duration of acid suppression was associated with stricture formation at hospital discharge (DC), 3-, 6-, and 9-months postoperatively.

RESULTS

Of 156 patients, 79 (51%) developed strictures and 60 (76%) strictures occurred within three months following repair. Acid suppression was used in 141 patients (90%). Landmark analysis showed acid suppression was not associated with reduction in initial stricture formation at DC, 3-, 6- and 9-months, respectively (p = 0.19-0.95). Multivariate regression demonstrated use of a transanastomotic tube was significantly associated with stricture formation at DC (Hazard Ratio (HR) = 2.21 (95% CI 1.24-3.95, p<0.01) and 3-months (HR 5.31, 95% CI 1.65-17.16, p<0.01). There was no association between acid suppression duration and stricture formation.

CONCLUSION

No association between the duration of postoperative acid suppression and anastomotic stricture was observed. Transanastomotic tube use increased the risk of anastomotic strictures at hospital discharge and 3 months after repair.

Impact of out-of-pocket expenses for surgical care on households in rural Haiti: a mixed-methods study

OBJECTIVES

This study aimed to report household catastrophic spending on surgery and the experiences of patients and families seeking surgical care in rural Haiti.

DESIGN

The study used an explanatory, sequential mixed-methods approach. We collected both quantitative and qualitative data from the participants through interviews.

SETTING

A rural tertiary hospital (St. Boniface Hospital) in southern Haiti.

PARTICIPANTS

There were 200 adult Haitian surgical patients who entered the study. Of these, 41 were excluded due to missing variables or health expenditure outliers. The final sample included 159 participants.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcomes were (1) direct and indirect payments for surgical care; (2) the rate of catastrophic health expenditure (CHE) (as defined by the Sustainable Development Goals (10% of total household expenditure) and WHO (10%, 20%, 30% and 40% of household capacity to pay)) due to surgical care; and (3) common themes across the lived experiences of households of surgical patients seeking care.

RESULTS

The median household expenditure on surgery-related expenses was US$385.6, slightly more than half of per capita gross domestic product in Haiti (US$729.3). Up to 86% of households experienced CHE, as defined by the Sustainable Development Goals, due to receiving surgical care. Patients commonly paid for surgical costs through loans and donations (69.8%). The qualitative analysis revealed prominent themes related to barriers to care including the burden of initiating care-seeking, care-seeking journeys and social suffering.

CONCLUSIONS

CHE is common for Haitian surgical patients, and the associated care-seeking experiences are often arduous. These findings suggest that low, flat fees in non-profit hospital settings may not be sufficient to mitigate the costs of surgical care or the resulting challenges that patients experience.

Evolution of Gender Disparities Among Brazilian Surgical, Anesthesia, and Obstetric Providers

INTRODUCTION

Since 2010, most graduating physicians in Brazil have been female, nevertheless gender disparities among surgical specialties still exist. This study aims to explore whether the increase in female physicians has translated to increased female representation among surgical specialties in Brazil.

METHODS

Data on gender, years of practice, and specialty was extracted from Demografia Médica do Brasil, from 2015 to 2020. The percentage of women across 18 surgical, anesthesia, and obstetric (SAO) specialties and the relative increases in female representation during the study period were calculated.

RESULTS

Of the 18 SAO specialties studied, 16 (88%) were predominantly male (>50%). Only obstetrics/gynecology and breast surgery showed a female predominance, with 58% and 52%, respectively. Urology, neurosurgery, and orthopedic surgery and traumatology were the three specialties with the largest presence of men - and the lowest absolute growth in the female workforce from 2015 to 2020.

CONCLUSIONS

In Brazil, where significant gender disparities persist, women are still underrepresented in surgical specialties. Female presence is predominant in surgical specialties dedicated to the care of female patients, while it remains poor in those with male patient dominance. Over the last 5 y, the proportion of women working in SAO specialties has grown, but not as much as in nonsurgical specialties. Future studies should focus on investigating the causes of gender disparities in Brazil to understand and tackle the barriers to pursuing surgical specialties.

Is authorship by women in Brazilian academic surgery increasing? A five-year retrospective analysis

Women remain underrepresented in 80% of Brazilian surgical specialties, however, women representation within the Brazilian academic surgical literature remains unknown. This study aims to evaluate the gender distribution of first and last authors in Brazilian surgical journals. All publications between 2015 and 2019 from the five Brazilian surgical journals with the highest impact factor were reviewed. The first and last authors' names were extracted from each article and a predictive algorithm was used to classify the gender of each author. Authors were further classified by surgical field and geographic region to investigate patterns of female authorship among journals, specialties, and region over the study period. Multivariable logistic regression was then used to identify factors independently associated with female authorship. 1844 articles were analyzed; 23% (426/1844) articles had female first authors, and 20% (348/1748) had female last authors. Acta Cirúrgica Brasileira was observed to have the highest rates for both first and last female authors (37%, 138/371; 26%, 95/370)) and Revista Brasileira de Ortopedia (9%, 48/542; 10%, 54/522) had the lowest rates. Papers with a woman senior author were twice as likely to have a woman first author (OR 1.98, 95% CI 1.51-2.58, p≤0.01). Women's representation in medicine is increasing in Brazil, yet women remain underrepresented as the first and last authors in the Brazilian surgical literature. Our results highlight the importance of senior women mentorship in academic surgery and demonstrate that promoting female surgeon senior authorship through academic and financial support will positively impact the number of female first authors.

Association between government policy and delays in emergent and elective surgical care during the COVID-19 pandemic in Brazil: a modeling study

Background

The impact of public health policy to reduce the spread of COVID-19 on access to surgical care is poorly defined. We aim to quantify the surgical backlog during the COVID-19 pandemic in the Brazilian public health system and determine the relationship between state-level policy response and the degree of state-level delays in public surgical care.

Methods

Monthly estimates of surgical procedures performed per state from January 2016 to December 2020 were obtained from Brazil's Unified Health System Informatics Department. Forecasting models using historical surgical volume data before March 2020 (first reported COVID-19 case) were constructed to predict expected monthly operations from March through December 2020. Total, emergency, and elective surgical monthly backlogs were calculated by comparing reported volume to forecasted volume. Linear mixed effects models were used to model the relationship between public surgical delivery and two measures of health policy response: the COVID-19 Stringency Index (SI) and the Containment & Health Index (CHI) by state.

Findings

Between March and December 2020, the total surgical backlog included 1,119,433 (95% Confidence Interval 762,663–1,523,995) total operations, 161,321 (95%CI 37,468–395,478) emergent operations, and 928,758 (95%CI 675,202–1,208,769) elective operations. Increased SI and CHI scores were associated with reductions in emergent surgical delays but increases in elective surgical backlogs. The maximum government stringency (score = 100) reduced emergency delays to nearly zero but tripled the elective surgical backlog.

Interpretation

Strong health policy efforts to contain COVID-19 ensure minimal reductions in delivery of emergent surgery, but dramatically increase elective backlogs. Additional coordinated government efforts will be necessary to specifically address the increased elective backlogs that accompany stringent responses.

Implementation of a checklist to improve pediatric trauma assessment quality in a Brazilian hospital

BACKGROUND

Trauma is the leading cause of death among children and adolescents in Brazil. Measurement of quality of care is important, as well as interventions that will help optimize treatment. We aimed to evaluate adherence to standardized trauma care following the introduction of a checklist in one of the busiest Latin American trauma centers.

MATERIAL AND METHODS

A prospective, non-randomized interventional trial was conducted. Assessment of children younger than age 15 was performed before and after the introduction of a checklist for trauma primary survey assessment. Over the study period, each trauma primary survey was observed and adherence to each step of a standardized primary assessment protocol was recorded. Clinical outcomes including mortality, admission to pediatric intensive-care units, use of blood products, mechanical ventilation, and number of CT scans in the first 24 h were also assessed.

RESULTS

A total of 80 patients were observed (39 pre-intervention and 41 post-intervention). No statistically significant differences were observed between the pre- and post-intervention groups in regard to adherence to checklist by specialty (57.7% versus 50.5%, p = 0.115) and outcomes. No mortality was observed.

CONCLUSION

In our trauma center, the quality of the adherence to standardized trauma assessment protocols is poor among both surgical and non-surgical providers. The quality of this assessment did not improve after the introduction of a checklist. Further work aimed at organizing the approach to pediatric trauma including triage and trauma education specifically for pediatric providers is needed.

The sticky surgical floor: An analysis of female authorship trends in vascular surgery

OBJECTIVE

Prior research in vascular surgery has identified significant gender disparities in leadership positions, but few data exist regarding gender disparities in vascular publications. This study aims to evaluate authorship trends by gender in the three highest impact factor vascular surgery journals.

METHODS

In this bibliometric analysis, PubMed was searched for articles published in the European Journal of Vascular and Endovascular Surgery, the Journal of Vascular Surgery, and Annals of Vascular Surgery from 2015 to 2019. The web-based application Genderize used predictive algorithms to classify names of first and last authors as male or female. Statistical analyses regarding trends in authorship were performed using Stata16.

RESULTS

A total of 6457 articles were analyzed, with first author gender predicted with >90% confidence in 83% (4889/5796) and last author gender in 88% (5078/5796). Overall, 25% (1223/4889) of articles had women first authors, and 10% (501/5078) had women last authors. From 2015 to 2019, there was a slight increase in the proportion of articles written by women first authors (P = .001), but no increase in the proportion of articles written by women last authors (P = .204). The proportion of articles written by women last authors was lower than the proportion of active women vascular surgeons in 2015 (8% of articles vs 11% of surgeons; P = .015), 2017 (9% of articles vs 13% of surgeons; P < .001), and 2019 (11% of articles vs 15% of practicing surgeons; P < .001). The average number of last-author publications was higher for men (2.35 ± 3.76) than for women (1.62 ± 1.88, P = .001). The proportion of unique authors who were women was less than the proportion of active women vascular surgeons in 2017 (10% unique authors vs 13% surgeons; P = .047), but not in 2015 (9% unique authors vs 11% surgeons; P = .192) or 2019 (13% unique authors vs 15% surgeons; P = .345). Notably, a woman last author was associated with 1.45 higher odds of having a woman first author (95% confidence interval, 1.17-1.79; P = .001).

CONCLUSIONS

Over the past 5 years, there has been no significant increase in women last authors among top-tier journals in vascular surgery. Women remain under-represented as last authors in terms of proportion of published articles, but not in terms of proportion of unique authors. Nevertheless, women last authors are more likely to publish with women first authors, indicating the importance of women-led mentorship in achieving publication gender equity. Support for women surgeons through grants and promotions is essential not only for advancing last authorship gender equity, but for advancing junior faculty and trainee academic careers.

Intravenous cephalosporin versus non-cephalosporin-based prophylaxis to prevent surgical site infections in colorectal surgery patients: A systematic review and meta-analysis

Background

Surgical site infection (SSI) is common in colorectal surgery patients and associated with morbidity and mortality. Guidelines recommend preoperative intravenous antimicrobial prophylaxis with aerobic and anaerobic coverage to reduce SSI risk. Cephalosporin based prophylaxis (CBP) regimens are recommended as first-line prophylaxis, and non-cephalosporin based are recommended as alternative prophylaxis (AP). We evaluate the efficacy of CBP versus AP in preventing surgical site infections in colorectal surgery patients.

Methods

A systematic review and meta-analysis was conducted of studies published between 2005 and 2020 in MEDLINE and Web of Science. Studies were excluded if intravenous antimicrobial prophylaxis was not administered, or if oral and intravenous prophylaxis were routinely co-administered. Heterogeneity was reported using the Q-statistic and I²-statistic. Publication bias was evaluated using a funnel plot and Egger test for small study effects. Statistical significance was defined as a two-sided p < 0.05.

Results

11 studies met inclusion criteria. AP was not associated with increased SSI risk at 30 days compared to CBP (OR 1.01, 95% CI 0.91, 1.13; OR < 1 favors AP). There was no effect size variability in subgroup analysis comparing higher-to lower-quality studies (I² = 99%, P = 0.17). Subgroup analysis by publication year approached a significant difference in effect size between studies published prior to 2014 and later than 2014 (I² = 99%, P = 0.06).

Conclusions

Meta-analysis of 11 studies of SSI risk in adult colorectal surgery patients suggest that SSI risk is similar for patients receiving CBP or AP, subgroup analysis of studies published since 2014 suggest increased SSI risk with AP compared to CBP.

•

Meta-Analysis found that surgical site infection risk is similar for patients receiving intravenous cephalosporin based or alternative prophylaxis.

•

Subgroup analysis of studies published since 2014 suggest increased surgical site infection risk with alternative prophylaxis compared to cephalosporin based prophylaxis.

•

RCT’s are needed to evaluate trends in SSI risk in cephalosporin-based prophylaxis compared to alternative prophylaxis.

General Surgery Applicants are Interested in Global Surgery, but Does It Affect Their Rank List?

BACKGROUND

The interest of medical students and surgery residents in global surgery continues to grow. Few studies have examined how the presence of global surgery opportunities influences an applicant's decision to choose a surgical training program. We designed a survey to examine the interest in global surgery among general surgery residency applicants and the influence of a global surgery rotation on a general surgery residency applicant's rank list.

METHODS

In March 2019, an online 20-question qualitative survey was administered to all general surgery applicants to a single academic institution. Results were stratified into two applicant groups; applicants from domestic or international medical schools. The survey was designed to capture demographic information, previous global rotations or experiences, future interest in global surgery opportunities, and the importance of global surgery in choosing a residency program.

RESULT

s: A total of 179 (21% response rate) applicants completed the entire survey. Of the respondents 81% were interested in a global surgery rotation during residency, 56% considered a global surgery opportunity as moderately to extremely important to their residency rankings, 71% said they would rank a residency higher if it had a funded global surgery program compared to one without funding and 58% of the surveyed applicants were interested in incorporating global surgery into their future career.

CONCLUSIONS

Global surgery opportunities are important to some general surgery residency applicants. A majority of applicants believe a funded global surgery would positively influence their rank list. As residency programs train residents for their future careers greater consideration needs to be given to developing global surgery opportunities.

The Impact of Increasing Surgical Capacity at a Tertiary Hospital in Southern Haiti

BACKGROUND

St. Boniface Hospital (SBH) plays a critical role in providing safe, accessible surgery in rural southern Haiti. We examine the impact of SBH increasing surgical capacity on case volume, patient complexity, and inpatient mortality across three phases.

MATERIALS AND METHODS

A retrospective review and geospatial analysis of all surgical cases performed at SBH between 2015 and 2017 were performed. Inpatient mortality was defined by in-hospital deaths divided by the number of procedures performed.

RESULTS

Between February 2015 and August 2017, over 2000 procedures were performed. The average number of surgeries per week was 3.1 with visiting surgical teams in phase 1 (P1), 10.4 with a single general surgeon in phase 2 (P2), and 20.1 with two surgeons and a resident in phase 3 (P3). There was a six-fold increase in surgical volume between P1 and P3 and a significant increase in case complexity. The distribution of American Society of Anesthesiologists scores of 1, 2, 3, and 4 during P2 was 81.05%, 14.74%, 3.42%, and 0.79%, respectively, whereas in P3, the distribution was 68.91%, 22.55%, 7.70%, and 0.84%. Surgical mortality was 0%, 1.2%, and 1.67% across phases.

CONCLUSIONS

Increasing resources and surgical staff at SBH allowed for greater delivery of safe surgical care. This study highlights that investing in surgery has a significant impact in regions of great surgical need.

Current status of international experiences in general surgery residency programs in the United States

Background

The aim of this study is to identify, quantify, and characterize the international experiences available for general surgery residents in the general surgery residency programs in the United States (US).

Methods

The Fellowship and Residency Electronic Interactive Database (FREIDA) database was used to identify all the general surgery residency programs in the US. Each institution was contacted by both e-mail and telephone. Respondents were asked if an international experience was available for residents within their program and, if available, details of the experience were obtained.

Results

A total of 253 general surgery residency programs were identified using the FREIDA database. Eighty-six (34 %) programs were noted to offer an international experience for their residents. A majority are incorporated into the PGY 3 and PGY 4 level of training with a duration of 1–4 weeks. Common locations are evenly distributed among the Americas and Africa and are usually funded through a combination of resident and department funding.

Conclusions

US resident interest in global health is growing along with an increasing demand for surgical care worldwide. This is one of the first studies to identify, quantify, and characterize in detail the international experiences currently available to general surgery residents within the general surgery training programs in the US. These results can help general surgery residency applicants with an interest in global health and also pave the path for residency programs to develop future international experiences.

Effect of Protein Concentration on the Flow of Cerebrospinal Fluid Through Shunt Tubing

BACKGROUND:

Protein levels in cerebrospinal fluid (CSF) are commonly thought to be related to sterile shunt malfunction.

OBJECTIVE:

To investigate the relationship between protein concentration and flow through CSF shunt tubing and a shunt valve.

METHODS:

New and explanted shunt catheters were tested with and without a shunt valve attached at various protein concentrations. The protein concentrations used were 0.5, 2, 5, and 10 g/L. A flask with artificial CSF attached to the proximal end provided flow. The flow was allowed to stabilize over 1 hour, and then the change in pressure between the proximal and distal end of the catheter was measured and recorded. The resistance to flow was calculated for new and explanted catheters for adult shunt systems, as well as with the addition of a programmable siphon control valve. The resistance was examined after the addition of various protein concentrations to a normal CSF solution.

RESULTS:

Both new and explanted catheters exhibited a decrease in the resistance to flow with higher concentrations of protein.

CONCLUSION:

In our laboratory setting, there was decreased resistance of adult CSF shunt catheters with and without a valve as the concentration of protein in the CSF increased. The decrease in the resistance of CSF shunt catheters with the addition of protein to the CSF may be related to the lowering of surface tension. This is the first study to examine the effects of varying protein concentrations across different lengths of shunt tubing for both new and explanted catheters.

Geospatial mapping to estimate timely access to surgical care in nine low-income and middle-income countries

BACKGROUND

The Lancet Commission on Global Surgery calls for universal access to safe, affordable, and timely surgical care. Two requisite components of timely access are (1) the ability to reach a surgical provider in a given timeframe, and (2) the ability to receive appropriately prompt care from that provider. We chose a threshold of 2 h in view of its relevance in time-to-death in post-partum haemorrhage. Here, we use geospatial mapping to enumerate the percentage of a nation's population living within 2 h of a surgeon and the surgeon-to-population ratio for each provider.

METHODS

Geospatial mapping was used to identify the population living within a 2-h driving distance (access zone) of a health-care facility staffed by a surgeon. Surgeon locations were extracted from Ministries of Health, professional society databases, and published literature for countries which had available data. Data were reviewed by individuals knowledgeable of in-country distribution. Spatial distribution of providers was mapped with Google Maps engine. Access zones were constructed around every provider through estimation of driving times in Google Maps. The number of people living within zones was estimated with the Socioeconomic Data and Applications Center Population Estimation Service. Surgeon-to-population ratios were constructed for every individual access zone and averaged to report a single ratio.

FINDINGS

Results (% country's population living within an access zone; average surgeon:population ratio within all access zones) are reported for nine countries with available data: Somaliland (16·9%; 1:118 306), Botswana (31·0%; 1:64 635), Ethiopia (39·6%; 1:229 696), Rwanda (41·3%; 1:158 484), Namibia (43·4%; 1:69 385), Zimbabwe (54%; 1:148 292), Mongolia (55·5%; 1:10 500), Sierra Leone (70·3%; 1:106 742), and Pakistan (84·4%, 1:139 299). Surgeon-to-population ratios vary substantially even within countries; in Sierra Leone, urban access zones have a ratio of 1:45 058 and rural access zones have a ratio of 1:467 929.

INTERPRETATION

Surgical access is poor in many low-income and middle-income countries, even when using a narrow definition of surgical access consisting only of timeliness. Living outside of an access zone makes timely access to surgical care highly unlikely, and in view of low surgeon-to-population ratios and poor prehospital transport, even living within a 2-h access zone might not confer 2-h access. Investments in infrastructure and training must be prioritised to address widespread disparity in access to timely surgery.

FUNDING

None.

Flow characteristics of cerebrospinal fluid shunt tubing

OBJECT

Cerebrospinal fluid shunt systems malfunction for a multitude of reasons, including malpostitioning, obstruction of the ventricular or distal catheter, obstruction of the shunt valve, and catheter disruptions or disconnections. The goal of this study was to examine the hydrodynamic resistance and flow in new and explanted catheters and also in catheters with 1 or 2 straight connectors.

METHODS

Explanted catheters of multiple lengths, 2-piece catheters, 3-piece catheters, and new catheters were attached to a proximal and distal manometer. A flask with artificial CSF attached to the proximal end provided flow. The flow was allowed to stabilize over 1 hour; then the change in pressure between the proximal and distal end of the catheter was measured.

RESULTS

The resistance to flow was calculated for new, never-implanted catheters and compared with the resistance of explanted distal shunt catheters. The resistance of the new catheters was examined after the addition of 1 and 2 straight connectors. Explanted catheters exhibited a slight increase in the resistance to flow of artificial CSF compared with new catheters. Two-piece and 3-piece catheters had a significant increase in resistance to flow compared with new catheters. For all catheters, resistance to flow increased as length increased (new, p = 0.01; explanted, p = 0.009; 1 connector, p = 0.01; 2 connectors, p = 0.03). In this paper, effective diameter is defined as the available cross-sectional area of catheter contacted by the artificial CSF. For new and explanted catheters, a decrease in the effective diameter of the catheter was associated with an increase in the resistance to flow of artificial CSF (new, p = 0.1083; explanted, p = 0.0091). However, after the addition of 1 or 2 connectors, an inverse trend was observed: resistance to flow increased with effective diameter.

CONCLUSIONS

There appears to be some increase in resistance of CSF shunt catheters as they age, altering flow dynamics. In addition, the use of straight connectors within a CSF shunt system increases the resistance to flow of artificial CSF within the shunt system. The increase in resistance appears to be related to the duration of implantation and the length of the catheter and inversely related to the diameter of the catheter. This increase in resistance may be related to sterile shunt malfunction. The addition of straight connectors is associated with a significant increase in resistance in comparison with catheters without connectors (p = 0.005).