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Biomedical subjects

Ronald F Sing

Publications and source records attributed to Ronald F Sing.

At least 37 records · Page 2Linked to original sources
PubMed2005

The role of transesophageal echocardiography in optimizing resuscitation in acutely injured patients.

BACKGROUND: The goal of resuscitation is to correct the mismatch between oxygen delivery and that of cellular demands. The pulmonary artery catheter (PAC) is frequently used to gauge the adequacy of resuscitation and guide therapy based on ventricular filling pressures. Transesophageal echocardiography (TEE) has emerged as a potential tool in assessing adequacy of acute hemodynamic resuscitation. The purpose of this study was to evaluate the role of TEE in assessing preload during ongoing volume resuscitation in trauma patients. METHODS: A retrospective review was conducted of acutely injured patients undergoing TEE during resuscitation from hemorrhagic shock from January 2002 to 2004 at a Level I trauma center. The indication for TEE was persistent hemodynamic instability in the absence of ongoing surgical hemorrhage. Variables included hemodynamic and PAC parameters, pre-TEE resuscitation volume, and vasopressor requirements. The impact of TEE findings on therapeutic decisions was evaluated. RESULTS: Twenty-five patients underwent TEE, 18 (72%) had an indwelling PAC with a mean pulmonary artery occlusion pressure of 19.3 mm Hg (range, 12-29 mm Hg) and mean cardiac index of 2.9 L/min/m2 (range, 1.6-4.6 L/min/m2). Twelve patients (48%) were receiving inotropes and/or vasopressors for hypotension at the time of TEE. Resuscitation volume within 6 hours before TEE included a mean of 6.5 L of crystalloid and 12.2 units of blood products (packed red blood cells, fresh frozen plasma, and platelets). TEE revealed left ventricular hypovolemia in 13 patients (52%) and altered therapy in 16 patients (64%), including additional volume (n = 13), addition of an inotrope (n = 4), and addition of a vasodilator (n = 1) in one patient with ventricular overdistention. Comparison of the abnormal and normal TEE groups revealed that only cardiac index was significantly different (2.6 L/min/m2 in the abnormal group vs. 3.9 L/min/m2 in the normal group; p = 0.005). Significant mitral valve regurgitation leading to valve replacement was identified in one patient. No clinically relevant pericardial effusion was identified. CONCLUSION: TEE altered resuscitation management in almost two thirds of patients. Many patients with "acceptable" pulmonary artery occlusion pressure parameters may in fact have inadequate left ventricular filling. In addition, TEE offers the advantage of direct assessment of cardiac valve competency, myocardial wall contractility, and pericardial fluid.

Adolescent↗
PubMed2005

Evaluation of the efficacy of the electrosurgical bipolar vessel sealer (LigaSure) devices in sealing lymphatic vessels.

Various sources of ultrasonic and thermal energy have been developed to facilitate blood vessel ligation. However, their efficacy in sealing lymphatics has not been clearly established to date. We hypothesized that the electrosurgical bipolar vessel sealer (EBVS) produces reliable and durable sealing of large lymphatic vessels in a porcine model. Thoracic ducts from 4 adult pigs were explanted and sealed at multiple levels by using 3 different EBVS devices: LigaSure Atlas, XTD, and V. Fifteen seals (5 per group) were analyzed for sealing time and visual quality. Seal burst strength was measured by using a graduated pressure saline injection system. Twelve intact seals also underwent a histologic analysis. The mean overall burst strength of the seals was 271+/-78 mm Hg (127 to 360 mm Hg). The burst pressures in the 3 groups were not statistically different. The overall mean time to achieve a seal was 5.1+/-2.2 seconds (3 to 10 seconds). Seals were achieved significantly faster in the V group (4.1+/-0.6 seconds) compared with the Atlas (6.3+/-2.3 seconds) and XTD (6.4+/-2.6 seconds) groups. Qualitative seal assessment revealed minimal sticking and charring, a favorable degree of seal tissue clarity, and desiccation in the 3 groups. Histologic analysis demonstrated a fusion of lymphovascular channels with a complete obliteration of the lumens. We demonstrated that the use of EBVS results in a fast and effective sealing of large porcine lymphatic vessels. The seals created by all 3 devices burst at markedly supraphysiologic intraluminal pressures. Ongoing randomized human trials may prove the clinical benefits of the routine use of EBVS devices for various tissue dissections.

Animals↗
PubMed2005

Optional vena cava filters for patients with high thromboembolic risk: questions to be answered.

The use of vena cava filters has increased rapidly over the past few years to more than 140,000 filters inserted worldwide in 2003. Continued improvements in filter design have increased the safety of intravascular caval filtration. Although there are many factors attributed to this increase, the most significant contributing factor has been the development of optional vena cava filters. That is, filters that can be left as a permanent device or can be removed endovascularly at a later date. Three filters are approved for removal in the United States, the Günther Tulip, the OptEase, and the Recovery. Recent reports have demonstrated the safety and feasibility of these devices in appropriate patients, but a number of questions have arisen regarding their use.

Device Removal↗
PubMed2005

National study of the effect of patient and hospital characteristics on bariatric surgery outcomes.

The influence of patient and hospital demographics on gastric bypass (GB) outcomes is unknown. We analyzed year 2000 data from the Nationwide Inpatient Sample database for all GB patients. In 2000, 5876 GB were performed in the 137 sample hospitals (M:F, 14%:86%). Length of stay (LOS, days), charges, comorbidities, and morbidity were higher for those aged >60 years compared to < 40 years. LOS, charges, comorbidities, morbidity, and mortality were highest in males. LOS was longest in African Americans compared to Caucasians and Hispanics. Charges and comorbidities were greatest in African Americans and Hispanics compared to Caucasians. Medicare and Medicaid-insured patients have higher LOS, charges, comorbidities, morbidity, and mortality compared to privately insured and self-pay patients. Lower income patients have higher LOS and total charges. Nonteaching hospitals have an increased LOS and charges and treat patients with more comorbidities compared to teaching hospitals. LOS, charges, and morbidity are directly proportional to hospital size. Urban hospitals have lower LOS and higher charges compared to rural hospitals. As hospital GB volume increases, LOS, charges, and morbidity decrease with no mortality effect. After controlling for all other covariates, male gender, increased age, and large hospital size were predictors of increased morbidity. Having had a complication predicted increased mortality, while female gender had a protective effect. Patient income, insurance status, and race did not play a role in morbidity or mortality. Neither academic, teaching status of the hospital or hospital gastric bypass volume influenced patient outcomes. Patient and hospital demographics do affect the outcomes of patients undergoing GB. Increasing age, male gender, and surgery performed in large hospitals are predictors of morbidity. Male gender and postoperative complications predict increased mortality. Neither comorbidities, race, payer, income, hospital academic status, location, nor hospital volume affect the outcome after GB.

Adult↗
PubMed2005

Prospective, blinded evaluation of accuracy of operative reports dictated by surgical residents.

Incomplete or inaccurate operative notes result in delayed, reduced, or denied reimbursement. Deficient reports may be more common when dictated by the surgical residents. We performed a blinded study to assess the accuracy of residents' dictations and their effect on the appropriate level of coding for reimbursement. A prospective, blinded study was performed comparing operative reports dictated by senior surgical residents (postgraduate years 3, 4, and 5) to reports dictated by attending surgeons. All residents had previously undergone group instruction on the importance and structure of operative notes. The trainees were blinded to the fact that the attending surgeons were dictating the operative reports on a separate dictation system. The dictations were analyzed by faculty reimbursement billing personnel for accuracy and completeness. Fifty operative reports of general surgical procedures dictated by both surgical residents and attending physicians were reviewed. A total of 97 CPT codes were used to report services rendered. Residents' dictations resulted in incorrect coding in 14 cases (28% error rate). The types of inaccuracies were a completely missed procedure (4) and insufficient documentation for an appropriate CPT code and/or modifier (10). All deficiencies occurred in complex, multicode, and/or laparoscopic cases. Sixty-seven per cent of late dictations were incomplete. The financial analysis revealed that deficiencies in resident dictations would have reduced the reimbursement by $18,200 (9.7%). For cases with deficient dictations, 29.5 per cent of charges would have been missed, delayed, or denied if the resident-dictated note was used to justify charges. Operative reports dictated by surgical residents are often incomplete or inaccurate, likely leading to reduced or delayed reimbursement. Dictations of complex, multicode, or laparoscopic surgeries, especially if delayed beyond 24 hours, are likely to contain significant deficiencies that affect billing. Attending surgeons may be better equipped to dictate complex cases. Formal housestaff education, mentorship by the attending faculty, and ongoing quality control may be paramount to minimize documentation errors to ensure appropriate coding for the services rendered.

Current Procedural Terminology↗
PubMed2004

Optimal closure method of five-millimeter trocar sites.

BACKGROUND: Although many surgeons use absorbable sutures for skin closure of 5-mm trocar sites, effective alternative materials exist. We compared 5-mm trocar site closures using a vicryl suture (VS), cyanoacrylate tissue adhesive (CTA), or skin tape (ST). METHODS: Patients rated wound pain and appearance at 1 and 6 weeks after surgery. Seven surgeons masked to the closure method rated wound photographs at these time points using the Hollander wound evaluation scale. Logistic regression analysis was used to evaluate the ratings of each closure group. RESULTS: The 137 wounds of 48 patients undergoing laparoscopic procedures were randomized among three closure method groups. Patient demographics and procedure type were similar for all groups. Long closure times (>30 seconds) was significantly higher for VS compared with CTA and ST. Patients favored VS over ST and CTA at 1 week with respect to pain and wound appearance (P = 0.04 and P = 0.02, respectively). They rated CTA closures more likely to have pain and poor wound appearance at 6 weeks (P = 0.05 and P = 0.03, respectively). Surgeons rated VS less likely (P = 0.02) and CTA more likely (P = 0.003) to show moderate to severe scar formation. Vicryl suture was less likely to have wound separation and edge inversion (P = 0.017 and P = 0.006, respectively). Cyanoacrylate tissue adhesive was more likely to yield step-off (P = 0.03), contour irregularities (P = 0.005), separation (P = 0.004), excessive distortion (P = 0.001), and edge inversion (P = 0.03). CONCLUSIONS: Although VS closure time of 5-mm trocar sites takes longer than CTA and ST, VS scar formation and comfort is superior to CTA and ST. Cyanoacrylate tissue adhesive yields poor results with respect to both wound healing and pain.

Equipment Design↗
PubMed2004

Laparoscopic splenectomy for splenic abscess.

Splenic abscess is a rare clinical entity, and splenectomy remains the treatment of choice. We sought to determine the safety and efficacy of laparoscopic splenectomy in this setting. Using a prospective database of laparoscopic splenectomy, we identified 4 patients who underwent surgery for splenic abscess (3 male, 1 female). Mean age was 55.5 (range 42-78) years. Patient symptoms included: fever and abdominal pain in 4 patients, pleural effusions in 2, and nausea and leukocytosis in 1. Risk factors for splenic abscess included septic emboli from bacterial endocarditis in 2 patients and acquired immune deficiency syndrome in 1. All patients underwent successful laparoscopic splenectomy. Mean operative time was 200 (range 160-220) minutes, and blood loss was 220 (range 100-450) mL. There were no postoperative complications or deaths; postoperative length of stay averaged 14 (range 2-26) days. Despite the difficulty of the operation, the laparoscopic approach appears to be a safe and effective treatment of splenic abscess.

Abscess↗
PubMed2004

Influence of demographics on colorectal cancer.

The purpose of this study was to examine the influence of race, gender, and age on colorectal cancer cases in our tumor registry between January 1987 and December 2000 and to determine the implications of these factors on screening strategies. Tumors were defined as early (Stage I/II) or late (Stage III/IV) and proximal or distal (relationship to splenic flexure). Effect of age was examined by stratifying patients into three groups (<50 years, 50-70 years, >70 years). Two time periods (1/87-12/96 and 1/97-12/00) were compared. Significance (P < 0.05) was determined by univariate and logistic regression analysis. Between January 1987 and December 2000, 1355 patients (M:F, 699:656; mean, 65.9 years) were entered into the tumor registry [998 whites, 357 African Americans (AA)]. The AA population had a significantly higher proportion of females (P = 0.0001) and patients <50 years (P = 0.01). The incidence of carcinoma in situ (CIS) was significantly higher in AA (P = 0.01). African Americans were more likely to present with late disease (P = 0.05), proximal cancers (P = 0.05), and well-differentiated tumors (P = 0.04). In the entire cohort, proximal lesions were significantly larger (P = 0.002), poorly differentiated (P = 0.002), and occurred more often in females (P = 0.03), patients >70 years (P = 0.04), and patients with family history of colon cancer compared to distal lesions. Proximal migration of tumors occurred in the latter part (1997-2000 compared to 1987-1996) of the study (P = 0.002). Patients <50 years had a higher incidence of late stage (P = 0.03) and poorly differentiated tumors (P = 0.009). The probability for a proximal tumor in an AA female >70 years was 61.9 per cent and in a white male >50 years was 35.1 per cent. Significant differences exist in the stage and location of tumors according to patient's age, race, and gender. These factors should be considered in implementing public screening strategies. Specifically, African-American patients were more likely to present with late-stage tumors, and more aggressive patient education and screening programs should be implemented. For all groups, a proximal migration of colorectal tumors was identified. This factor should eliminate use of sigmoidoscopy as a screening tool. Complete colonoscopy, instead, should be the procedure of choice to identify colonic neoplasia.

Adenocarcinoma↗
PubMed2003

Factors affecting intravenous analgesic requirements after colectomy.

BACKGROUND: The purpose of this study was to determine factors that influence postoperative IV analgesic use after colectomy. STUDY DESIGN: We retrospectively evaluated patients who underwent colectomy between January 1997 and December 2000 at our medical center and calculated the amount of postoperative IV narcotics needed in morphine equivalents. Statistical differences (p < 0.05 considered significant) were measured using the Wilcoxon rank-sum test. Correlations were performed using Spearman correlation coefficients, and linear regression analysis was also performed. RESULTS: Four hundred eighty-one patients (235 men, 246 women) underwent colectomy; patients had a mean age of 60.6 years (range, 17 to 96 years). Procedures performed included total/subtotal colectomy (10%, n = 49), right colectomy (42%, n = 200), transverse colectomy (3%, n = 12), left/sigmoid colectomy (40%, n = 195), and low anterior resection (4%, n = 17). Laparoscopic colectomy was performed in 53 (11%) patients. Mean postoperative morphine equivalent use was 160.2 mg. Narcotic analgesic use was significantly less for women (p = 0.02), diagnosis of cancer (p = 0.02), and laparoscopic colectomy (p = 0.0001). Patients undergoing a right colectomy required less postoperative narcotics than patients having other types of colectomies (p < 0.02). There was a positive correlation between postoperative narcotic use and operative time (r = 0.14, p = 0.007) and a negative correlation with patient age (r = -0.37, p = 0.0001). Linear regression analysis demonstrated that age (p = 0.0001), female gender (p = 0.04), and laparoscopy (p = 0.001) were independent predictors for decreased narcotic use. CONCLUSIONS: Postoperative IV narcotic analgesic use is affected by gender, patient age, indication for colectomy, operative time, type of procedure, and operative technique.

Adolescent↗
PubMed2003

Laparoscopic gastric bypass surgery: equipment and necessary tools.

Advanced laparoscopy in the morbidly obese patient is technically challenging. Having the proper instrumentation and equipment available is a major component of technical success. Items routinely used during surgery performed on patients of normal size must often be modified or substituted when morbidly obese patients undergo surgery. In this article, we review the specific tools necessary for the safe and proper completion of laparoscopic Roux-en-Y gastric bypass, in addition to various alternatives that can be helpful when other procedures are performed on morbidly obese patients.

Bioelectric Energy Sources↗
PubMed2003

A comparison of laparoscopic bipolar vessel sealing devices in the hemostasis of small-, medium-, and large-sized arteries.

INTRODUCTION: The development of new energy sources for hemostasis has facilitated advanced laparoscopic procedures. Few studies, however, have documented the strength of the vessels sealed or the extent of surrounding lateral thermal injury, two important factors in maintaining hemostasis while preventing injury to surrounding structures. This study compared the burst pressure and extent of thermal injury of vessels sealed with the 5-mm laparoscopic PlasmaKinetics trade mark sealer (PK) (Gyrus Medical, Maple Grove, Minnesota) and the 5-mm laparoscopic LigaSure trade mark sealing device (LS) (Valleylab, Boulder, Colorado). METHODS: Arteries in three sizes (2-3 mm, 4-5 mm, and 6-7 mm) were harvested from domestic pigs. Eight to 17 specimens from each size were randomly sealed with the PK, and the same number with the LS. Burst pressures were measured in mm Hg. The extent of thermal injury, determined by coagulation necrosis, was measured microscopically in millimeters after staining the transected vessels with hematoxylin and eosin. Descriptive statistics, including means and standard deviations, are reported. Student's t-test and ANOVA were performed to determine significance (P <.05). RESULTS: The mean bursting pressures of the PK and the LS were equal in the 2-3 mm vessels (397 vs. 326 mm Hg, P =.49). The PK bursting pressures were significantly less than the LS in the 4-5 mm (389 vs. 573 mm Hg, P =.02) and the 6-7 mm groups (317 vs. 585 mm Hg, P =.0004). As vessel size increased, the PK was associated with significantly lower burst pressures, while the LS was associated with progressively higher burst pressures (P =.035). Thermal spread was not significantly different between the PK and the LS in the 2-3 mm (1.5 vs. 1.2 mm, P =.27), the 4-5 mm (2.4 vs. 2.4 mm, P =.79), or the 6-7 mm vessel size groups (3.2 vs. 2.5 mm, P =.32). Increasing vessel size, regardless of instrument used, was associated with increased thermal injury (P <.0001). CONCLUSION: The LS produces supraphysiologic seals with significantly higher bursting pressures than the PK in vessels ranging from 4 to 7 mm. The PK seals become progressively weaker while the LS seals increase in strength as the vessel size increases. Although thermal spread increases with vessel size, the degree of lateral thermal injury is no different between the two instruments.

Animals↗
PubMed2003

Physiologic predictors of survival in post-traumatic arrest.

Traumatic cardiac or pulmonary arrest is often associated with a dismal outcome and is considered by many to be an example of medical futility and inappropriate use of resources. This study aimed to identify the predictors of survival in patients experiencing traumatic cardiac arrest. We retrospectively reviewed all trauma patients undergoing cardiopulmonary resuscitation on arrival to the Emergency Department (ED) at an American College of Surgeons-designated Level I trauma center over 4 years. ED survival, hospital survival, and neurologic outcomes on discharge were the primary outcomes. Survival rates were examined in relation to demographics, mechanism of injury, airway management, cardiac electrical rhythm, and pupil size and reactivity. Statistical analyses used chi-square and t tests, P < 0.05 was considered significant. A total of 195 patients arrived in the ED with traumatic cardiac arrest; 34 were pronounced dead on arrival (no signs of life), and no resuscitation efforts were initiated. Of the remaining 161 patients 53 (33%) survived to leave the ED, and only 15 (9%) left the hospital alive. Demographic features were similar in survivors and nonsurvivors. The setting of intubation (prehospital vs ED) did not influence survival (P = 0.36). Penetrating trauma adversely affected survival in the ED (P = 0.01); however, this only approached significance in the final outcome of hospital survival (P = 0.06). The presence of sinus rhythm and nondilated reactive pupils was highly significant in predicting ED and hospital survival (P = 0.001). No patient with agonal rhythm or ventricular fibrillation/tachycardia survived, and 14 of the 15 hospital survivors had reactive pupils on arrival to the ED. We conclude that sinus rhythm and pupil size and reactivity are important physiologic variables that predict potential survival and may be used to guide continuation of resuscitative efforts in patients with traumatic cardiac arrest.

Adolescent↗
PubMed2003

Clinical characteristics and outcomes of surgical patients with vancomycin-resistant enterococcal infections.

The purpose of this study is to determine risk factors associated with mortality in surgical patients with vancomycin-resistant enterococcus (VRE) infections. The hospitalizations of surgical patients with VRE infections from January 1998 to December 2001 were reviewed. Statistical analysis was performed using the Student's t test, chi square, and Fisher's exact test. Thirty-one surgical patients (male:female, 14:17) with a mean age of 51.9 years (range, 21-83 years) developed VRE infection. Infections included bacteremia (12), urinary tract (11), surgical site (seven), and soft tissue (five) infections and intra-abdominal abscess (one). Nine (29.0 per cent) patients received recent outpatient antibiotics and 20 (64.5 per cent) were on steroids. Fifteen (48.4 per cent) patients were treated with intravenous vancomycin before infection. Twelve (38.1 per cent) patients died with a trend toward advanced age (60.7 vs 46.5 years; P = 0.06). The incidence of VRE infection in kidney transplant patients was 1.8 per cent. Six transplant patients (five kidney and one kidney/ pancreas) developed VRE infections with four deaths. Hypertension (P = 0.04), coronary artery disease (P = 0.02), and the need for intra-arterial pressure monitoring (P = 0.04) were associated with mortality. Isolate location, gender, diabetes, renal dysfunction, respiratory disease, liver disease, and serum albumin were not associated with mortality. Kidney transplant patients have a high incidence of VRE infection. Surgical patients with VRE infections have a high mortality rate. Hypertension and coronary artery disease are risk factors for mortality.

Adult↗
PubMed2003

The role of vena caval filters in the management of venous thromboembolism.

Deep venous thrombosis (DVT) and pulmonary embolism (PE) are important, and not infrequent, causes of morbidity and mortality in critically ill patients. Anticoagulation remains the treatment of choice for DVT and PE, but contraindications to, and complications from, anticoagulant therapy mandate the availability of alternate therapeutic and prophylactic strategies. The recent availability of safe and effective vena caval filters that can be inserted via a minimally invasive percutaneous approach has expanded the indications for, and acceptance of, these devices in selected patients at high risk for the development of PE. This article reviews both the established and the evolving indications for vena caval filters and discusses how improvements in filter design may impact future use.

Anticoagulants↗
PubMed2003

Overview of current inferior vena cava filters.

Inferior vena cava (IVC) filter technology has expanded dramatically over the past decade. Improvements in catheter and filter technology have allowed for the safe and rapid insertion of IVC filters from multiple venous access sites, using increasingly lower-profile percutaneous delivery systems. While the currently available filters have slightly different designs and insertion techniques, all function in a similar fashion to prevent venous thromboembolic propagation through the inferior vena cava. This article describes the construction and deployment mechanisms of the various filters that are currently on the market.

Equipment Design↗
PubMed2003

Complications of inferior vena cava filters.

Inferior vena cava (IVC) filters offer a safe and effective means of preventing pulmonary embolus and have reduced complications when compared to earlier techniques of caval interruption. However, despite continued improvement in filters and insertion methods, complications still occur. Pneumothorax, hemorrhage, and vessel injury may result while obtaining vascular access. Filter misplacement, excessive tilt, and vascular injury have been reported with insertion, but preinsertion cavography is helpful in preventing these insertion-related complications. Attention to detail, proper use of guidewires, and preinsertion imaging are vital in preventing insertion-related complications as well. Long-term complications occur in a minority of patients and include recurrent pulmonary embolus, caval occlusion, and filter migration. Overall, the benefits of preventing pulmonary embolism far exceed the risks related to filter placement in properly selected patients.

Humans↗
PubMed2003

Bedside insertion of the inferior vena cava filter in the intensive care unit.

Historically, inferior vena cava (IVC) filters have been inserted in the Radiology Department or the Operating Room. When initially designed, vena cava filters required surgical cut down of the internal jugular vein to insert a large (24 French) introducer and it was therefore necessary to perform this procedure in the operating room. Percutaneous methods (e.g., the Seldinger technique) with smaller profile sheath-dilator devices (6 to 12 French) have made IVC filter insertion a much easier procedure. Furthermore, the remaining equipment is simple, portable, and readily available throughout most hospitals (e.g., C-arm, contrast, sterile drapes, gowns, gloves, catheters, etc.). These factors have made it easy to "bring the procedure to the patient." This is particularly advantageous in critically ill ICU patients. Complication rates of "road trips" for critically ill patients from the ICU to other parts of the hospital (i.e., radiology department or operating room) can result in a mishap rate of 5-30. Secondary benefits of bedside insertion of vena cava filters include cost-effectiveness.

Costs and Cost Analysis↗