Craig A. Reickert

Extracorporeal life support in pulmonary failure after trauma

OBJECTIVE To present a series of 30 adult trauma patients who received extracorporeal life support (ECLS) for pulmonary failure and to retrospectively review variables related to their outcome. METHODS In a Level I trauma center between 1989 and 1997, ECLS with continuous heparin anticoagulation was instituted in 30 injured patients older than 15 years. Indication was for an estimated mortality risk greater than 80%, defined by a PaO2: FIO2 ratio less than 100 on 100% FIO2, despite pressure-mode inverse ratio ventilation, optimal positive end-expiratory pressure, reasonable diuresis, transfusion, and prone positioning. Retrospective analysis included demographic information (age, gender, Injury Severity Score, injury mechanism), pulmonary physiologic and gas-exchange values (pre-ECLS ventilator days [VENT days], PaO2:FIO2 ratio, mixed venous oxygen saturation [SvO2], and blood gas), pre-ECLS cardiopulmonary resuscitation, complications of ECLS (bleeding, circuit problems, leukopenia, infection, pneumothorax, acute renal failure, and pressors on ECLS), and survival. RESULTS The subjects were 26.3+/-2.1 years old (range, 15-59 years), 50% male, and had blunt injury in 83.3%. Pulmonary recovery sufficient to wean the patient from ECLS occurred in 17 patients (56.7%), and 50% survived to discharge. Fewer VENT days and more normal SvO2 were associated with survival. The presence of acute renal failure and the need for venoarterial support (venoarterial bypass) were more common in the patients who died. Bleeding complications (requiring intervention or additional transfusion) occurred in 58.6% of patients and were not associated with mortality. Early use of ECLS (VENT days < or = 5) was associated with an odds ratio of 7.2 for survival. Fewer VENT days was independently associated with survival in a logistic regression model (p = 0.029). Age, Injury Severity Score, and PaO2:FIO2 ratio were not related to outcome. CONCLUSION ECLS has been safely used in adult trauma patients with multiple injuries and severe pulmonary failure. In our series, early implementation of ECLS was associated with improved survival. Although this may represent selection bias for less intractable forms of acute respiratory distress syndrome, it is our experience that early institution of ECLS may lead to improved oxygen delivery, diminished ventilator-induced lung injury, and improved survival.

Predictors of critical care-related complications in colectomy patients using the National Surgical Quality Improvement Program: exploring frailty and aggressive laparoscopic approaches.

BACKGROUND: Colectomy patients experience a broad set of adverse outcomes. Complications requiring critical care support are common in this group. We hypothesized that as frailty increases, the risk of Clavien class IV and V complications will increase in colectomy patients. METHODS: Using the National Surgical Quality Improvement Program (NSQIP) participant use files for 2005–2009, we identified patients who underwent laparoscopic and open colectomies by Current Procedural Terminology code. Using the Clavien classification for postoperative complications, we identified NSQIP data points most consistent with Clavien class IV requiring intensive care unit (ICU) care or class V complications (death). We used a modified frailty index with 11 variables based on mapping the Canadian Study of Health and Aging Frailty Index and existing NSQIP variables. Logistic regression was performed to acuity adjust the findings. RESULTS: A total of 58,448 colectomies were identified. As frailty index increased from 0 to 0.55, the proportion of those experiencing Clavien class IV or V complications increased from 3.2% at baseline to 56.3%. Variables found to be significant by logistic regression (odds ratio) were frailty index (14.4; p = 0.001), open procedure (2.35; p < 0.001), and American Society of Anesthesiologists class 4 (3.2; p = 0.038) or 5 (7.1; p = 0.001) while emergency operation and wound classification 3 or 4 were not. CONCLUSIONS: Complications requiring ICU care represent a significant morbidity in the colectomy patient population. Frailty index seems to be an important predictor of ICU-level complications and death, and laparoscopy seems to be protective. LEVEL OF EVIDENCE: II, prognostic.

Effect of rate and inspiratory flow on ventilator-induced lung injury.

BACKGROUND We examined the effects of decreasing respiratory rate (RR) at variable inspiratory times (It) and reducing inspiratory flow on the development of ventilator-induced lung injury. METHODS Forty sheep weighing 24.6+/-3.2 kg were ventilated for 6 hours with one of five strategies (FIO2 = 1.0, positive end-expiratory pressure = 5 cm H2O): (1) pressure-controlled ventilation (PCV), RR = 15 breaths/min, peak inspiratory pressure (PIP) = 25 cm H2O, n = 8; (2) PCV, RR = 15 breaths/min, PIP = 50 cm H2O, n = 8; (3) PCV, RR = 5 breaths/min, PIP = 50 cm H2O, It = 6 seconds, n = 8; (4) PCV, RR = 5 breaths/min, PIP = 50 cm H2O, It = 2 seconds, n = 8; and (5) limited inspiratory flow volume-controlled ventilation, RR = 5 breaths/min, pressure-limit = 50 cm H2O, flow = 15 L/min, n = 8. RESULTS Decreasing RR at conventional flows did not reduce injury. However, limiting inspiratory flow rate (LIFR) maintained compliance and resulted in lower Qs/Qt (HiPIP = 38+/-18%, LIFR = 19+/-6%, p < 0.001), reduced histologic injury (HiPIP = 14+/-0.9, LIFR = 2.2+/-0.9, p < 0.05), decreased intra-alveolar neutrophils (HiPIP = 90+/-49, LIFR = 7.6+/-3.8,p = 0.001), and reduced wet-dry lung weight (HiPIP = 87.3+/-8.5%, LIFR = 40.8+/-17.4%,p < 0.001). CONCLUSIONS High-pressure ventilation for 6 hours using conventional flow patterns produces severe lung injury, irrespective of RR or It. Reduction of inspiratory flow at similar PIP provides pulmonary protection.

Prenatal ultrasonography frequently fails to diagnose congenital diaphragmatic hernia

Despite increased use of prenatal ultrasonography and well-defined guidelines to aid in the detection of congenital diaphragmatic hernia (CDH), approximately half of neonates born with CDH undergo a prenatal scan that does not diagnose the defect. The purpose of this study was to (1) examine the use of prenatal ultrasonography in neonates with CDH, (2) determine possible reasons that contributed to the failure to detect the abnormality, and (3) evaluate the clinical impact of a diagnostic versus a nondiagnostic study. From 1985 to 1995, 136 consecutive neonates with CDH symptomatic within 24 hours of birth were treated at the University of Michigan Medical Center. Medical records and a University of Michigan CDH database were reviewed for prenatal ultrasound status, side of herniation, site of birth, survival, and extracorporeal life support (ECLS) use. Sonograms that did not diagnose CDH were collected and reviewed by a radiologist for possible-reasons why the diagnosis was missed. Over the 10-year period, use of ultrasonography increased from 33% to 100%, but the false-negative rate remained approximatedly 55%. In reviewing 40 nondiagnostic studies in 25 patients, 25% had technical difficulties, 57% failed to follow established guidelines (localization of the stomach and visulization of the heart with all four chambers), and 33% missed findings (intrathoracic stomach and mediastinal shift) consistent with CDH. There was no significant difference in survival or use of ECLS between neonates with a diagnostic versus nondiagnostic study (53% v 77% survival, P = 0.09; 64% v 42% ECLS, P = .29) Careful attention to following established guidelines and an increased appreciation for the abnormalities would be expected to increase the sensitivity of ultrasonography in detecting CDH. Increased prenatal diagnosis will allow for thorough evaluation for associated malformations, detection of chromosomal abnormalities, and early referra with intrauterine transport to a tertiary care center before delivery.

Congenital diaphragmatic hernia survival and use of extracorporeal life support at selected level III nurseries with multimodality support.

BACKGROUND Congenital diaphragmatic hernia (CDH) has been cited to have a mortality rate of 50%. There have been multiple studies at individual institutions demonstrating potential benefits from various strategies including extracorporeal life support (ECLS), delayed repair, and lower levels of ventilator support. There has been no multicenter survey of institutions offering these modalities to describe the current use of ECLS and survival of these infants. In addition, the relationship between the number of patients with CDH managed at an individual institution and outcome has not been evaluated. METHODS We queried 16 level III neonatal intensive care centers on the use of ECLS and survival of infants with CDH who were treated during 2 consecutive years (1993 to 1995). Data are presented as mean +/- SEM, median, and range. RESULTS Data were collected on 411 patients. Of these, 71% +/- 8% were outborn and 8% +/- 3% were considered nonviable. Overall survival of CDH infants was 69% +/- 4% (range, 39% to 95%). The survival rate of infants on ECLS was 55% +/- 4%, whereas survival of infants not requiring ECLS was significantly increased at 81% +/- 5% (p = 0.005). The mean rate of ECLS use was 46% +/- 2%. There was no correlation between the number of cases per year at an individual institution and overall survival, ECLS survival, or ECLS use (r = 0.341, 0.305, and 0.287, respectively). There was also no correlation between case volume at an individual institution and ECLS survival (r = 0.271). CONCLUSIONS The current survival rate and rate of ECLS use in infants with CDH at level III neonatal intensive care units in the United States are 69% +/- 4% and 46% +/- 2%, respectively. There is no correlation between the yearly individual center experience with managing CDH and rate of ECLS use or outcome.

Characteristics of an albumin dialysate hemodiafiltration system for the clearance of unconjugated bilirubin.

Extraction of protein bound liver failure toxins, such as unconjugated bilirubin, short chain fatty acids, and aromatic amino acids has been reported using hemodiafiltration with albumin in the dialysate, but the characteristics of such a system have not been described. Therefore, bilirubin clearance using albumin dialysate hemodiafiltration was evaluated in the setting of different dialysate albumin concentrations, varying temperature, and pH. An in vitro continuous hemodiafiltration circuit was used with single pass countercurrent dialysis. Unconjugated bilirubin was added to bovine blood and filtered across a polyalkyl sulfone (PAS) hemofilter using matched filtration and dialysate flow rates. The serial bilirubin content was measured and first order clearance kinetics verified. The clearance rate constants were calculated for three dialysate groups of different albumin concentration at constant temperature and pH (group 1:10 g/dl albumin, n = 5; 2 g/dl albumin, n = 5; normal saline, n = 5), and three groups of different temperature and pH at constant albumin dialysate concentration (group 2: pH = 7.0, temperature = 20° C, n = 5; pH = 7.5, temperature = 20° C, n = 5; pH = 7.0, temperature = 40° C, n = 5). Comparisons were made with ANOVA and Tukey post hoc analysis. When albumin was used in the dialysate, the 2 g/dl group cleared bilirubin 3.1 times faster than saline alone (p = 0.001), and the 10 g/dl group was superior to both (p = 0.001). There were no measurable differences between the 2 g/dl groups at the various temperatures tested (p = 0.08), but the clearance was less at a pH of 7.5 (p = 0.015). The clearance of unconjugated bilirubin is greatly enhanced with the use of albumin containing dialysates when compared to traditional crystalloid hemodiafiltration, is greater at lower pH, and seems to be unaffected by temperature. ASAIO Journal 1997; 43:M745-M749.

Clostridium difficile of the ileum following total abdominal colectomy, with or without proctectomy: Who is at risk?

BACKGROUND: Clostridium difficile enteritis is considered a rare entity, although recent data suggest a significant increase in prevalence and incidence. There is paucity of data evaluating risk factors of C difficile enteritis following total colectomy. OBJECTIVE: The aim of this study was to determine the incidence and risk factors of C difficile enteritis for patients who had undergone total abdominal colectomy with or without proctectomy. DESIGN: This study involves a retrospective chart review of 310 patients. Univariate analysis was performed on potential risk factors (p ⩽ 0.05) with the use of a logistic regression model, and a Fisher exact test was used for variables that had no occurrences of C difficile. These groups of variables were then examined in a multiple variate setting with stepwise logistic regression analysis. SETTINGS: This study was conducted at a tertiary referral center. PATIENTS: A data analysis was performed on patients who had undergone total abdominal colectomy with or without proctectomy who were tested for C difficile of the ileum. RESULTS: Twenty-two of 137 patients that were tested (16%) were positive for C difficile of the ileum. Univariate analysis of known risk factors for C difficile demonstrated that black race was a protective factor against C difficile (p = 0.016). The multivariate analysis demonstrated that emergency surgery (p = 0.035), race (p = 0.003), and increasing age by decade (p = 0.033) were risk factors for C difficile. LIMITATIONS: This study was limited by the small patient sample, and it was not a randomized trial. CONCLUSIONS: Black race is protective, and whites are 4 times more likely to acquire C difficile of the ileum after undergoing a total abdominal colectomy with or without proctectomy. The data also demonstrated that an increased age by a decade and emergency surgery are risk factors for C difficile enteritis, whereas the described risk factors of C difficile of the colon and type of colon surgery do not appear to influence the risk of C difficile of the ileum.

Partial liquid ventilation and positive end-expiratory pressure reduce ventilator-induced lung injury in an ovine model of acute respiratory failure

Objective To examine the isolated and combined effects of positive end-expiratory pressure (PEEP) and partial liquid ventilation (PLV) on the development of ventilator-induced lung injury in an ovine model. Design Prospective controlled animal study. Setting University-based cardiovascular animal physiology laboratory. Subjects Thirty-eight anesthetized supine sheep weighing 22.3 ± 2.2 kg. Interventions Animals were ventilated for 6 hrs (respiratory rate, 15; Fio2, 1.0, inspiratory/expiratory ratio, 1:1) with one of five pressure-controlled strategies, expressed as peak inspiratory pressure (PIP)/PEEP: low-PIP, 25/5 cm H2O (n = 8); high-PIP, 50/5 cm H2O (n = 8); high-PIP-PLV, 50/5 cm H2O-PLV (n = 8); high-PEEP, 50/20 cm H2O (n = 7); and high-PEEP-PLV, 50/20 cm H2O-PLV (n = 7). Measurements and Main Results Compared with the low-PIP control, high-PIP ventilation increased airleak, shunt, histologic evidence of lung injury, neutrophil infiltrates, and wet lung weight. Maintaining PEEP at 20 cm H2O or adding PLV reduced the development of physiologic shunt and dependent histologic injury indexes. Neither higher PEEP nor PLV reduced the high incidence of barotrauma observed in high-PIP animals. Conclusions We conclude that application of PLV or PEEP at 20 cm H2O may improve gas exchange and afford lung protection from ventilator-induced lung injury during high-pressure mechanical ventilation in this model.

Prolonged partial liquid ventilation in spontaneously breathing awake animals

OBJECTIVE To date, studies of partial liquid ventilation (PLV) have examined its effects acutely in anesthetized and mechanically ventilated subjects. We set out to develop a model of prolonged PLV in awake, spontaneously breathing animals. DESIGN Animal case series SETTING Cardiopulmonary physiology laboratory. SUBJECTS Fifteen New Zealand white rabbits (3.2+/-0.39 kg). INTERVENTIONS Animals were anesthetized and instrumented with a novel technique allowing percutaneously assisted placement of an intratracheal catheter with a subcutaneously tunneled externalized free end. After anesthetic recovery, PLV was performed in spontaneously breathing unsedated animals. MEASUREMENTS AND MAIN RESULTS Evaporative losses were determined using a single 10 mL/kg perflubron dose (n = 5); hourly radiographs were obtained until residual perflubron was minimal. For prolonged PLV (n = 10), a 10-mL/kg initial perflubron dose was followed every 4 hrs with 5-mL/kg supplements. Radiographs were obtained immediately before and after perflubron administration and were scored (0-5) by a radiologist blinded to dosing regimen and time interval. Data were analyzed with ANOVA and Students t-test with correction for multiple comparisons. Initial filling was nearly complete (score = 4.8+/-0.42); lungs were maintained approximately half-filled through 4 hrs (score = 2.53+/-0.71). By 6 hrs, the majority of perflubron had evaporated (score = 1.75+/-0.53). Over 24 hrs, radiographs documented continuous perflubron exposure (postffill = 4.53+/-0.64, prefill = 3.40+/-0.71, average = 3.97+/-0.43); scores were comparatively higher after filling (after = 4.53+/-0.64, before = 3.4+/-0.71, p< .001). Left and right lung volumes were equivalent (left = 4.06+/-0.47, right = 3.89+/-0.39, p = .027). All animals survived the 24 hrs of PLV. CONCLUSIONS Percutaneously assisted intratracheal cannulation with catheter exteriorization permits prolonged PLV in spontaneously breathing, unsedated animals. Continuous perfluorocarbon exposure with this method is reproducible, consistent, and well tolerated for 24 hrs in uninjured animals.

The value proposition of simulation

BACKGROUND Simulation has been shown to improve trainee performance at the bedside and in the operating room. As the use of simulation-based training is expanded to address a host of health care challenges, its added value needs to be clearly demonstrated. Demonstrable improvements will support the expansion of infrastructure, staff, and programs within existing simulation facilities as well as the establishment of new facilities to meet growing needs and demands. Thus, organizational and institutional leaders, faculty members, and other stakeholders can be assured of the best use of existing resources and can be persuaded to make greater investments in simulation-based training for the future. METHODS A multidisciplinary panel was convened during the 8th Annual Meeting of the Consortium of the American College of Surgeons-Accredited Education Institutes (Simulation Centers) in March 2015 to discuss the added value of simulation-based training. Panelists shared the ways in which the value of simulation was demonstrated at their institutions. CONCLUSION The value of simulation-based training was considered and described in terms of educational impact, patient care outcomes, and costs.