Insights from CTTACC: immune system reset by cellular therapies for chronic illness after trauma, infection, and burn

BACKGROUND AIMS

In this paper, we present a review of several selected talks presented at the CTTACC conference (Cellular Therapies in Trauma and Critical Care) held in Scottsdale, AZ in May 2023. This conference review highlights the potential for cellular therapies to "reset" the dysregulated immune response and restore physiologic functions to normal. Improvements in medical care systems and technology have increasingly saved lives after major traumatic events. However, many of these patients have complicated post-traumatic sequelae, ranging from short-term multi-organ failure to chronic critical illness.

METHODS/RESULTS

Patients with chronic critical illness have been found to have dysregulated immune responses. These abnormal and harmful immune responses persist for years after the initial insult and can potentially be mitigated by treatment with cellular therapies.

CONCLUSIONS

The sessions emphasized the need for more research and clinical trials with cellular therapies for the treatment of a multitude of chronic illnesses: post-trauma, radiation injury, COVID-19, burns, traumatic brain injury (TBI) and other chronic infections.

How does Injury Severity Score derived from International Classification of Diseases Programs for Injury Categorization using International Classification of Diseases, Tenth Revision, Clinical Modification codes perform compared with Injury Severity Score derived from Trauma Quality Improvement Program?

BACKGROUND

Injury Severity Score (ISS) is a measurement of injury severity based on the Abbreviated Injury Scale. Because of the difficulty and expense of Abbreviated Injury Scale coding, there have been recent efforts in mapping ISS from administrative International Classification of Diseases ( ICD ) codes instead. Specifically, the open source and freely available International Classification of Diseases Programs for Injury Categorization (ICDPIC) in R (Foundation for Statistical Computing, Vienna, Austria) converts International Classification of Diseases, Ninth Revision, codes to ISS. This study aims to compare ICDPIC calculations versus manually derived Trauma Quality Improvement Program (TQIP) calculations for International Classification of Diseases, Tenth Revision ( ICD-10 ), codes. Moderate concordance was chosen as the hypothetical relationship because of previous work by both Fleischman et al. ( J Trauma Nurs. 2017;24(1):4-14) who found moderate to substantial concordance between ICDPIC and ISS and Di Bartolomeo et al. ( Scand J Trauma Resusc Emerg Med. 2010;18(1):17) who found none to slight concordance. Given these very different findings, we thought it reasonable to predict moderate concordance with the use of more detailed ICD-10 codes.

METHODS

This was an observational cohort study of 1,040,728 encounters in the TQIP registry for the year 2018. International Classification of Diseases Programs for Injury Categorization in R was used to derive ISS from the ICD-10 codes in the registry. The resulting scores were compared with the manually derived ISS in TQIP.

RESULTS

The median difference between ISS calculated by ICDPIC-2021 using ICD-10, Clinical Modification (ISS-ICDPIC), and manually derived ISS was -3 (95% confidence interval, -5 to 0), while the mean difference was -2.09 (95% confidence interval, -2.10 to -2.07). There was substantial concordance between ISS-ICDPIC and manually derived ISS ( κ = 0.66). The ISS-ICDPIC was a better predictor of mortality (area under the curve, 0.853 vs. 0.836) but a worse predictor of intensive care unit admission (area under the curve, 0.741 vs. 0.757) and hospital stay ≥10 days (AUC, 0.701 vs. 0.743). The ICDPIC has substantial concordance with TQIP for the firearm ( κ = 0.69), motor vehicle trauma ( κ = 0.71), and pedestrian ( κ = 0.73) injury mechanisms.

CONCLUSION

When TQIP data are unavailable, ICDPIC remains a valid way to calculate ISS after transition to ICD-10 codes. The ISS-ICDPIC performs well in predicting a number of outcomes of interest but is best served as a predictor of mortality.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Defining obstacles to emergency transfer of trauma patients: An evaluation of retriage processes from nontrauma and lower-level Illinois trauma centers

BACKGROUND

Retriage is the emergency transfer of severely injured patients from nontrauma and lower-level trauma centers to higher-level trauma centers. We identified the barriers to retriage at sending centers in a single health system.

METHODS

We conducted a failure modes effects and criticality analysis at 4 nontrauma centers and 5 lower-level trauma centers in a single health system. Clinicians from each center described the steps in the trauma assessment and retriage process to create a process map. We used standardized scoring to characterize each failure based on frequency, impact on retriage, and prevention safeguards. We ranked each failure using the scores to calculate a risk priority number.

RESULTS

We identified 26 steps and 93 failures. The highest-risk failure was refusal by higher-level trauma centers (receiving hospitals) to accept a patient. The most critical failures in the retriage process based on total risk, frequency, and safeguard scores were (1) refusal from a receiving higher-level trauma center to accept a patient (risk priority number = 191), (2) delay in a sending center's consultant examination of a patient in the emergency department (risk priority number = 177), and (3) delay in receiving hospital's consultant calling back (risk priority number = 177).

CONCLUSION

We identified (1) addressing obstacles to determining clinical indications for retriage and (2) identifying receiving level I trauma centers who would accept the patient as opportunities to increase timely retriage. Establishing clear clinical indications for retriage that sending and receiving hospitals agree on represents an opportunity for intervention that could improve the retriage of injured patients.

Assessing the utility of deep neural networks in predicting postoperative surgical complications: a retrospective study

BACKGROUND

Early detection of postoperative complications, including organ failure, is pivotal in the initiation of targeted treatment strategies aimed at attenuating organ damage. In an era of increasing health-care costs and limited financial resources, identifying surgical patients at a high risk of postoperative complications and providing personalised precision medicine-based treatment strategies provides an obvious pathway for reducing patient morbidity and mortality. We aimed to leverage deep learning to create, through training on structured electronic health-care data, a multilabel deep neural network to predict surgical postoperative complications that would outperform available models in surgical risk prediction.

METHODS

In this retrospective study, we used data on 58 input features, including demographics, laboratory values, and 30-day postoperative complications, from the American College of Surgeons (ACS) National Surgical Quality Improvement Program database, which collects data from 722 hospitals from around 15 countries. We queried the entire adult (≥18 years) database for patients who had surgery between Jan 1, 2012, and Dec 31, 2018. We then identified all patients who were treated at a large midwestern US academic medical centre, excluded them from the base dataset, and reserved this independent group for final model testing. We then randomly created a training set and a validation set from the remaining cases. We developed three deep neural network models with increasing numbers of input variables and so increasing levels of complexity. Output variables comprised mortality and 18 different postoperative complications. Overall morbidity was defined as any of 16 postoperative complications. Model performance was evaluated on the test set using the area under the receiver operating characteristic curve (AUC) and compared with previous metrics from the ACS-Surgical Risk Calculator (ACS-SRC). We evaluated resistance to changes in the underlying patient population on a subset of the test set, comprising only patients who had emergency surgery. Results were also compared with the Predictive OpTimal Trees in Emergency Surgery Risk (POTTER) calculator.

FINDINGS

5 881 881 surgical patients, with 2941 unique Current Procedural Terminology codes, were included in this study, with 4 694 488 in the training set, 1 173 622 in the validation set, and 13 771 in the test set. The mean AUCs for the validation set were 0·864 (SD 0·053) for model 1, 0·871 (0·055) for model 2, and 0·882 (0·053) for model 3. The mean AUCs for the test set were 0·859 (SD 0·063) for model 1, 0·863 (0·064) for model 2, and 0·874 (0·061) for model 3. The mean AUCs of each model outperformed previously published performance metrics from the ACS-SRC, with a direct correlation between increasing model complexity and performance. Additionally, when tested on a subgroup of patients who had emergency surgery, our models outperformed previously published POTTER metrics.

INTERPRETATION

We have developed unified prediction models, based on deep neural networks, for predicting surgical postoperative complications. The models were generally superior to previously published surgical risk prediction tools and appeared robust to changes in the underlying patient population. Deep learning could offer superior approaches to surgical risk prediction in clinical practice.

FUNDING

The Novo Nordisk Foundation.

Brain Metabolism Monitoring through CCO Measurements Using All-Fiber-Integrated Super-Continuum Source

For monitoring of concussion, brain function, organ condition and other medical applications, what is needed is a non-invasive method of monitoring tissue metabolism. MRI-based functional imaging technology detects changes in blood oxygenation, a correlate of neural activity, and thus may offer a prediction of prognosis in cases of concussion and other cerebral traumas. Yet, potential relationships between perturbations to cerebral metabolism and patient outcomes cannot be effectively exploited clinically because we lack a practical, low-cost, non-invasive means to monitor cerebral oxygenation and metabolism in the emergency department, operating room, or medical facilities. We have developed a device to optically assay the redox state of Cytochrome-C-Oxidase (CCO), the mitochondrial enzyme responsible for the last step of the electron transport chain. Changes in CCO redox reflect changes in respiratory flux, and thus changes in the rate of oxidative adenosine triphosphate (ATP) synthesis. In other words, changes in CCO reflect brain cell's metabolic activity more directly than the traditional blood oxygenation measurement methods. To non-invasively measure changes in CCO as well as blood oxygenation, we have developed a Super-Continuum Infrared Spectroscopy of Cytochrome-C-Oxidase (SCISCCO) system that uses an all-fiber integrated, super-continuum light source to simultaneously measure both of the new (CCO) and the traditional (blood oxygenation) markers of neural metabolism. The SCISCCO system is validated by confirming the near-infrared spectrum of CCO in vitro. To demonstrate in vivo feasibility, the measured responses of oxygenation and CCO responses to acute ischemia (e.g., blood pressure tests) in human participants are compared to data from the literature. Furthermore, we show that the new device's measurements of oxygenated (HbO) and deoxygenated (HbR) hemoglobin in response to breath hold challenges are principled and consistent with previously reported findings. The validated SCISCCO system is finally applied to measure cerebral oxygenation and the redox state of CCO in participants during an attention test protocol. Twenty-five healthy adults completed an attention task that included nine 60-second periods of attention task, interleaved with 60-s periods of resting baseline. It has been well established that the frontal lobe of the human brain is active during tasks of attention. We therefore predicted that attention task should elicit an increase in HbO concentration accompanied by a decrease in redox state of CCO (e.g., ratio of oxidized CCO to reduced CCO) in frontal lobe brain regions as measured with the SCISCCO system. Our findings are consistent with our predictions: HbO concentration increases while CCO concentration decreases during the attention blocks relative to the resting baseline, thereby indicating an increase in oxidative metabolism of the frontal lobe brain regions of interest. Our systematic, multi-method approach thus validates the new device as well as the validity of the metabolic biomarkers that it measures. The SCISCCO system could be a new tool for monitoring brain and organ metabolism, which could be invaluable for screening concussion patients or use in an operating or emergency room to gauge patient's organ response to treatments.

Ureteral Involvement Within an Incarcerated Inguinal Hernia in a Patient With Crossed-fused Renal Ectopia

Crossed-fused renal ectopy is an uncommon abnormality of the genitourinary tract that results from errors during embryological development. Ureteral herniation represents another rare anatomic event and can often occur from spontaneous, postoperative, and congenital causes (Allam, Johnson, Grewal & Johnson 2015; Pollack, Popky & Blumberg 1975). Here, we discuss the complex clinical course of a patient with crossed-fused renal ectopia who presents with symptoms due to ureteroinguinal herniation and provide a brief overview of the literature. We highlight the clinical considerations in the management of this patient and provide a potential anatomical and embryological explanation for his presentation.

Beneficial effects of histone deacetylase inhibition with severe hemorrhage and ischemia-reperfusion injury

BACKGROUND

Valproic acid (VPA) is a histone deacetylase inhibitor that may decrease cellular metabolic needs following traumatic injury. We hypothesized that VPA may have beneficial effects in preventing or reducing the cellular and metabolic sequelae of ischemia-reperfusion injury.

METHODS

Twenty-eight Yorkshire swine underwent 35% blood volume hemorrhage, followed by a lethal truncal ischemia-reperfusion injury and 6 h of resuscitation. Physiologic and laboratory parameters were closely measured and the pigs divided into four groups: sham, control (injury protocol), VPA dosing before cross-clamp (VPA-B), and VPA dosing after cross-clamp (VPA-A).

RESULTS

All animals developed significant coagulopathy, acidosis, and anemia. Animals receiving VPA-A had decreased acidosis and coagulopathy as measured by pH (P = 0.016) and international normalized ratio (P = 0.013) over the resuscitation. VPA-A pigs had a decreased requirement for crystalloid (P = 0.007) and epinephrine (P < 0.0001) during resuscitation. Pathologic analysis demonstrated decreased liver injury with VPA administration. VPA administration increased levels of acetylated proteins in liver and lung tissues, and was associated with increased expression of heat shock protein 70 versus controls.

CONCLUSIONS

Valproic acid conferred a significant cardiovascular, metabolic, and pathologic protective effect in a model of severe injury. Earlier administration (VPA-B) was significantly less effective compared with dosing after initial hemorrhage control.

Fifty-four emergent cricothyroidotomies: are surgeons reluctant teachers?

BACKGROUND

Emergent cricothyroidotomy remains an uncommon, but life-saving, core procedural training requirement for emergency medicine (EM) physician training. We hypothesized that, although most cricothyroidotomies occur in the emergency department (ED), they are rarely performed by EM physicians.

METHODS

We conducted a retrospective analysis of all emergent cricothyroidotomies performed at two large level one trauma centers over 10 years. Operators and assistants for all procedures were identified, as well as mechanism of injury and patient demographics were examined.

RESULTS

Fifty-four cricothyroidotomies were performed. Patients were: mean age of 50, 80% male and 90% blunt trauma. The most common primary operator was a surgeon (n = 47, 87%), followed by an Emergency Medical Services (EMS) provider (n = 6, 11%) and a EM physician (n = 1, 2%). In all cases, except those performed by EMS, the operator or assistant was an attending surgeon. All EMS procedures resulted in serious complications compared to in-hospital procedures (p < 0.0001).

CONCLUSIONS

1. Pre-hospital cricothyroidotomy results in serious complications. 2. Despite the ubiquitous presence of emergency medicine physicians in the ED, all crico-thyroidotomies were performed by a surgeon, which may represent a serious emergency medicine training deficiency.

Intraparenchymal vs extracranial ventricular drain intracranial pressure monitors in traumatic brain injury: less is more?

BACKGROUND

Management of severe traumatic brain injury has centered on continuous intracranial pressure (ICP) monitoring with intraparenchymal ICP monitors (IPM) or extracranial ventricular drains (EVD). Our hypothesis was that neurologic outcomes are unaffected by the type of ICP monitoring device.

STUDY DESIGN

We reviewed 377 adult patients with traumatic brain injury requiring ICP monitoring. Primary outcome was Glasgow Outcome Score (GOS) 1 month after injury. Secondary outcomes included mortality, monitoring-related complications, and length of ICU and hospital stay.

RESULTS

There were 253 patients managed with an IPM and 124 with an EVD. There was no difference in Glasgow Outcome Score (2.7 ± 1.3 vs 2.5 ± 1.3, p = 0.45), mortality (30.9% vs 32.2%, p = 0.82), and hospital length of stay (LOS) (15.6 ± 12.4 days vs 16.4 ± 10.7 days, p = 0.57). Device-related complications (11.9% vs 31.1%, p < 0.001), duration of ICP monitoring (3.8 ± 2.6 days vs 7.3 ± 5.6 days, p < 0.001), and ICU LOS (7.6 ± 5.6 days vs 9.5 ± 6.2 days, p = 0.004) were longer in the EVD group. Age, opening ICP, and size of midline shift were independent predictors for neurologic outcomes and mortality, when type and severity of brain injury, as well as overall injury severity were controlled for. Duration of ICP monitoring and opening ICP were independent predictors for hospital LOS and the former predicted prolonged ICU stay. Device-related complications were affected by type of device.

CONCLUSIONS

Use of EVDs in adult traumatic brain injury patients is associated with prolonged ICP monitoring, ICU LOS, and more frequent device-related complications.

Status of HIV infection among the pregnant women attending in outpatient department

Human immunodeficiency virus (HIV) infection has been spreading rapidly in the developing countries and vertical transmission also taking place. This study has been done to find out the prevalence of HIV infection among the pregnant women, so that necessity of routine screening test can be identified. It is a cross sectional study. Five hundred two pregnant women were included. Three ml venous blood was taken and then HIV screening test was done by ELISA method. All reactive tests were confirmed by Western blot antibody testing. The positive cases were followed up and necessary treatment was given. Delivery was conducted in this hospital. Baby's blood was tested to see vertical transmission after 18 months. Most of the subject were educated housewife, mean age was 25 years. Six (6%) husband was overseas service holder, 12% were smoker and 1.6% had drug addiction. Eight (8%) subject had previous history of blood transfusion and 49% subject or her husband had history of surgery or got parental therapy. 2% subject gave the history of familial disharmony and 2% had multiple sex partners. HIV infection was found in 2 patients (0.4%). Both of them got infection from their husband. One husband was over seas service holder and another one was injecting drug user. For the prevention of spread, reduction of vertical transmission and providing early management to the positive patient all pregnant women should be screened for HIV routinely.

Characteristics of infertile couples

The objective of the study was to evaluate the sociodemographic characteristics and to find out the causes of infertility among the couple attending out patient department of infertility unit in Bangabandhu Sheikh Mujib Medical University (BSMMU) from January to December 2007. This is a descriptive observational study. Data were analyzed done manually and statistical analysis was calculated by Statistical package for social sciences (SPSS) program. During this period 3184 patients were attended out patient department (OPD) of infertility unit (IU-I & II). Among them primary infertility was present in 1971(61.90%) and secondary infertility in 1213(38%) cases. One thousand four hundred and two (1402) patient's complete data were reviewed from OPD register book of IU-I. The mean duration of the infertility was 4.7(4.52) years. The mean age of female patient was 26.5±5.35 years. The mean age of male patient was 34.56±6.33 years. A positive male factor problem alone was found in 13% couples, female factors in 71.46% couples and unexplained infertility in 15.47% couples. Among the male factor Oligozoospermia (33.33%) was the most common cause of male infertility. Anovulation (52.16%) was the most common cause of female infertility and major cause of anovulation was Polycystic ovary syndrome (PCOS) (29.90%). Fibroid uterus, Bilateral tubal block and Pelvic inflammatory disease (PID) were significantly (p<0.001) higher in secondary infertility. Endometriosis and unexplained infertility were significantly (p<0.001) higher in primary infertility. Distribution of other causes of infertility was same for both primary and secondary infertility.

Ethical awareness in surgical management

Getting information about disease has been suffering, the management needed, procedure and complication of that management, is the right of the patients. Giving that information to the patients is the responsibility of the physician/surgeons. The objective of this study was to assess the existing awareness of the surgeons and female patients regarding ethical issues of medical practices. This observational study was undertaken in the gynecological department of two tertiary hospital of the capital city of Bangladesh. One hundred fifty five patients were interviewed who were underwent surgical management for different gynecological problems. Mean age of the studied population was 41 (SD+/-10) years. All of them were from lower and lower middle economical classes. Sixty three percents (63%) were illiterate. Consent for the surgery was given by the husband in 52% cases, by son in 22% cases, by herself in 1% case and remaining by other relatives. About 50% of the patients did not know the name of their disease, 75% of them never talked with the surgeon. Only in 31% cases surgeon spontaneously explained them about her disease. Most of them had no knowledge about anaesthesia, operating time, need of blood transfusion, operating complications and long-term effects of the surgery they had. The result of this study showed very poor awareness about medical ethics and patient's right.

Diazoxide, as a postconditioning and delayed preconditioning trigger, increases HSP25 and HSP70 in the central nervous system following combined cerebral stroke and hemorrhagic shock

Combined hemorrhagic shock (Shock) and unilateral common carotid artery occlusion (Stroke) results in a decrease of oxygen availability to peripheral tissues and organs and the central nervous system (CNS). A variety of biochemical processes ensue, including organ failure, cellular apoptosis, and necrosis. The present study used male, Sprague-Dawley rats to assess the impact of cerebral insult. Using heat-shock protein 25 and 70 (HSP25, HSP70) as biomarkers, measured 24 h after injury, we tested the hypothesis that pharmacological induction of preconditioning can offer cytoprotection from combined Stroke and Shock. The compound, diazoxide (DZ), is known to induce preconditioning through its effect as a mitochondrial potassium ATP (mK(ATP)) channel opener and succinate dehydrogenase inhibitor. When administered 24 h prior to Stroke and Shock (delayed preconditioning), DZ increased cerebral cortical and hippocampal levels of HSP25 and HSP70. A more clinically relevant treatment paradigm was tested, where DZ was administered after the induction of Stroke and Shock (postconditioning). When administered 60 min (but not 10 min) after the induction of Stroke and Shock, DZ significantly increased HSP25 and HSP70 expression in the ipsilateral cerebral cortex and hippocampus. Taken together, these results suggest that DZ treatment may be efficacious for CNS injury resulting from blood loss and anoxia from combined cerebral ischemia and hemorrhagic shock. "Postconditioning" triggered by DZ, immediately before resuscitation, is a potentially effective treatment for ischemia-reperfusion injury from combined Stroke and Shock.

A portable cardiopulmonary bypass/extracorporeal membrane oxygenation system for the induction and reversal of profound hypothermia: feasibility study in a Swine model of lethal injuries

The Cleveland Clinic Foundation's (CCF) cardiopulmonary bypass/extracorporeal membrane oxygenation (CPB/ECMO) system capabilities were tested in a hypothermia trauma management feasibility study in a porcine animal model at the Uniformed Services University of the Health Sciences (USUHS, Bethesda, MD, U.S.A.). In this survival series, the CCF system was used in a simulated forward lines combat casualty application where lethal uncontrolled hemorrhage from major vascular injuries was repaired under a state of profound hypothermic arrest (suspended animation), followed by recovery and monitoring in an intensive care unit (ICU) setting. The animals were monitored for survival, neurological impact, cognitive functions, organ damage, and delayed complications over 3 weeks. A survival rate of 83% matched rates previously found using conventional equipment. Neurological findings, organ dysfunction, and complication rates also were no different from previous studies using standard equipment. Successful survival results demonstrated that the CCF CPB/ECMO system could be used to induce a period of profound hypothermic arrest for the repair of lethal traumatic injuries. The logistical advantages of this system make it an attractive choice for use in austere settings and during transport.

Laser Doppler imaging determines need for excision and grafting in advance of clinical judgment: a prospective blinded trial

INTRODUCTION

Clinicians' judgment as to which burns require excision and grafting remains one aspect of burn care without objective measurements. This study presents a prospective, blinded trial to assess decision to operate by laser Doppler imaging (numerical criteria) versus the clinical judgment of an experienced burn surgeon.

METHODS

A number of 23 patients were enrolled in this prospective trial and 41 representative wounds of indeterminate depth were selected for observation. Daily determination of need to operate (burn depth) was made by a single burn surgeon. Laser Doppler imager (LDI) scans of the same wounds were simultaneously obtained, and not revealed to the clinician. Data analysis compared quickness of decision to operate by LDI to the clinician's judgment. Concurrence of decisions by either method was compared.

RESULTS

A total of 23 patients and 41 wounds were analyzed. LDI and the surgeon agreed in determination of wound depth 56% of the time (23/41, P=0.031). Biopsy confirmation was obtained for 21 wounds. The surgeon's determination of burn depth was accurate in 71.4% of wounds biopsied (15/21). When the LDI scan median flux indicated need for excision, it was 100% accurate (7/7). When both the surgeon and the LDI were correct in assessing wound depth, LDI would have saved median number of 2 days (minimum=0, maximum=4).

CONCLUSION

LDI allowed for earlier, objective determination of need to operate. Concurrence with clinical judgment in this blinded study was excellent. LDI should be seen as an effective aid to clinical judgment when contemplating excision of burns with indeterminate depth.

Comparison of the effects of a 50% exchange-transfusion with albumin, hetastarch, and modified hemoglobin solutions

We compared the hemodynamic effects of replacing 50% of the blood volume of anesthetized rats with an equal volume of five solutions: human serum albumin (HSA), hetastarch, unmodified hemoglobin, diaspirin-crosslinked hemoglobin, and o-raffinose-crosslinked hemgolobin. Control rats were exchange-transfused with their own blood. HSA and hetastarch caused a severe reduction in systemic vascular resistance (SVR), hypotension, and acute renal failure immediately after the exchange-transfusion. Unmodified and diaspirin-crosslinked hemoglobins caused comparable and severe increases in SVR, whereas vasoconstriction induced by o-raffinose-crosslinked hemoglobin was minimal. The increased SVR induced by all hemoglobin solutions resolved over a 2-day period as the hemoglobin was cleared from plasma. Body weight was monitored for 5 days after the exchange transfusion as a measure of the relative long-term efficacy of the exchange solutions tested and increased substantially in control rats (that received blood). Rats that received both crosslinked hemoglobin solutions gained a comparable amount of weight as the control group. By contrast rats that received HSA, hetastarch and unmodified hemoglobin failed to gain weight or lost weight over the same period. In summary: i) HSA and hetastarch are relatively ineffective as resuscitative fluids when administered after the loss of a large volume of blood; ii) diaspirin-crosslinked hemoglobin causes severe vasoconstriction, comparable in intensity to that induced by unmodified hemoglobin; iii) o-raffinose-crosslinked hemoglobin induces minimal vasoconstriction; iv) the vasoactive effects of all hemoglobin solutions are reversible. We conclude, that of all solutions tested, both the short- and long-term effects of an exchange-transfusion with whole blood are most closely reproduced by an exchange with o-raffinose-crosslinked hemoglobin.

Visceral ischemia after cardiopulmonary bypass

The diagnosis and management of gastrointestinal complications associated with cardiopulmonary bypass is often hindered by a complicated clinical picture and equivocal examination. To better define the incidence, risk factors, and mortality, we reviewed the records of all patients undergoing cardiopulmonary bypass from 1988 through 1996. The database for this study comprised 14,521 patients who underwent cardiac surgery. The patients (543) with gastrointestinal complications were identified, and those with major complications (166) were individually reviewed. Major complications included pancreatitis, gastritis, laparotomy, gastric ulcer, cholecystitis, colonic perforation, gastrointestinal bleeding, diverticulitis, bowel obstruction, perforation, and visceral ischemia. Our results were the following. 1) Gastrointestinal complications were noted in 3.7 per cent (543) of patients with major complications occurring in 1.2 per cent. In 166 patients, 187 major complications were noted. 2) Visceral ischemia, an infrequent but usually fatal (71%) complication, occurred in 24 (0.17%). 3) Of the ischemic events, 83 per cent (20 of 24) affected the bowel; with the colon involved 80 per cent of the time (16 of 20). 4) Patients with visceral ischemia were more likely to be female (relative risk 2.1), have longer pump times (92.2 versus 74.2), have cardiac procedures other than coronary artery bypass graft (relative risk 2.6), and have end-stage renal disease (relative risk 16.7). We conclude that, given the incidence and mortality related to visceral ischemia, especially to the colon, patients with risk factors (end-stage renal disease, female sex, non-coronary artery bypass graft, and longer pump times) should undergo routine endoscopic examination of the colon early after bypass and when clinically indicated thereafter.

Visceral Ischemia after Cardiopulmonary Bypass

The diagnosis and management of gastrointestinal complications associated with cardiopulmonary bypass is often hindered by a complicated clinical picture and equivocal examination. To better define the incidence, risk factors, and mortality, we reviewed the records of all patients undergoing cardiopulmonary bypass from 1988 through 1996. The database for this study comprised 14,521 patients who underwent cardiac surgery. The patients (543) with gastrointestinal complications were identified, and those with major complications (166) were individually reviewed. Major complications included pancreatitis, gastritis, laparotomy, gastric ulcer, cholecystitis, colonic perforation, gastrointestinal bleeding, diverticulitis, bowel obstruction, perforation, and visceral ischemia. Our results were the following. 1) Gastrointestinal complications were noted in 3.7 per cent (543) of patients with major complications occurring in 1.2 per cent. In 166 patients, 187 major complications were noted. 2) Visceral ischemia, an infrequent but usually fatal (71%) complication, occurred in 24 (0.17%). 3) Of the ischemic events, 83 per cent (20 of 24) affected the bowel; with the colon involved 80 per cent of the time (16 of 20). 4) Patients with visceral ischemia were more likely to be female (relative risk 2.1), have longer pump times (92.2 versus 74.2), have cardiac procedures other than coronary artery bypass graft (relative risk 2.6), and have end-stage renal disease (relative risk 16.7). We conclude that, given the incidence and mortality related to visceral ischemia, especially to the colon, patients with risk factors (end-stage renal disease, female sex, non-coronary artery bypass graft, and longer pump times) should undergo routine endoscopic examination of the colon early after bypass and when clinically indicated thereafter.

A placental-derived tissue matrix as a bowel wall substitute in rats: preliminary study

BACKGROUND

Occasionally, conventional closure of an intestinal wall defect (fistula) is not possible. The development of a biologic material that can be used in this setting would solve a significant clinical problem. We hypothesized that a collagen patch (connective tissue matrix [CTM]) designed to allow tissue regeneration was such a material.

METHODS

To test this hypothesis, we performed a laparotomy on 75 male Sprague-Dawley rats (experiment A) and removed 25% of the anterior cecal wall (1 cm in diameter) to compare intestinal wound healing in four situations: (1) control (no repair), (2) fibrin glue repair, (3) primary repair, and (4) repair with CTM (human placental bilayer, types I, III, and IV). Animals were killed at 1, 2, 4, and 6 weeks. Healing was graded by bursting pressure expressed in millimeters of mercury, histologic score (0 to 4), and mortality rates. After this, we used the same protocol to remove 80% of the cecal wall (1.5 x 2.0 cm) in 19 animals (experiment B) to compare (5) fibrin glue repair alone with (6) CTM repair in a situation in which the defect was too large for primary repair.

RESULTS

CTM repair of a lethal cecal wall defect (experiment A) is equivalent to either primary repair or fibrin glue repair. When the defect is too large for primary repair (experiment B), repair with fibrin glue also does not work. However, in this same setting, CTM repair is successful (p < 0.00001).

CONCLUSIONS

Intestinal wall defects not suitable for conventional closure can be repaired successfully with a collagen patch, with histologic characteristics similar to those seen with primary repair.

Does resuscitation produce a reperfusion injury?

Conceptually, shock with resuscitation should produce cellular changes that parallel those observed in a single organ exposed to ischemia with reperfusion, i.e., a transient worsening of the injury pattern after reperfusion with the degree of recovery reflecting the magnitude of the ischemic injury. To test this hypothesis, 74 male Sprague Dawley rats (300-400 g) were randomized into two groups with controls and exposed to 1) hemorrhagic shock (mean arterial pressure < 50 mm Hg) for 2 hours before sacrifice, or 2) shock (2 hours) with reinfusion of shed blood over 1 hour before sacrifice. Mean arterial pressure, blood loss, serum lactate, base excess, and bicarbonate were serially measured to determine the degree of tissue ischemia. At sacrifice, hepatic mitochondrial function was determined by the respiratory control ratio. Our findings were as follows: 1) Hemorrhagic shock produced significant (P < 0.001) tissue ischemia and impairment of mitochondrial function (P < 0.001), 2) resuscitation rapidly corrects the metabolic sequelae of tissue ischemia, and 3) mitochondrial function was unaffected by resuscitation. We conclude that resuscitation rapidly corrects the tissue ischemia associated with hemorrhagic shock, without producing any measurable reperfusion injury at the mitochondrial level.

Portal vein thrombosis in the adult: surgical implications in an era of dynamic imaging

Extrahepatic portal vein thrombosis (EHPVT) is the leading cause of variceal hemorrhage in patients with healthy livers; however, in an era of dynamic imaging, the incidental discovery of EHPVT places a special burden on the surgeon to understand the surgical implications of the disease in this setting. During the period 1989 to 1995, 23 patients (12 males and 11 females) were found to have EHPVT. In 20 (87%), this was an unexpected finding on ultrasound (11 of 23), abdominal CT scan (9 of 23), or both (9 of 23). In two patients, the diagnosis was suspected and confirmed with angiography, whereas in the other, the lesion was discovered at surgery. Only seven (30%) had hemorrhage as a presenting complaint. More typically (61%), abdominal pain alone or pain with sepsis was the indication for evaluation. In 20 patients (87%), there was an identifiable etiology for the EHPVT. A total of 15 operations were performed on 12 patients (52%), in 7 (4, variceal hemorrhage, and 3, bowel ischemia) as a direct consequence of the EHPVT and in five, for conditions not directly related to the EHPVT. Three of the 23 patients (13%) died, two (17%) following surgery and one (9%) from advanced malignant disease. No patients with hemorrhage (seven), even those who required a shunt for decompression (three) or devascularization (one), died. We found that the diagnosis of EHPVT is usually not related to variceal hemorrhage, but rather, abdominal symptoms that serve as an indication for the imaging study. Three subsets of patients emerged: (1) those requiring no surgery (11 patients), (2) those requiring surgery related to hemorrhage (4 patients), and (3) those requiring surgery for conditions other than varices (8 patients). In any of these circumstances, mortality (13%) was related to the underlying disease process rather than EHPVT. Given the earlier recognition of EHPVT, the natural history of the disease has been altered, with outcome reflecting the underlying disease rather than the sequelae of portal hypertension.

A five-year prospective study of the health of children in different ethnic groups, with particular reference to the effect of inbreeding

A 5-year prospective study of 4,934 children of different ethnic groups has demonstrated a 3-fold increase of postneonatal mortality and childhood morbidity in the offspring of consanguineous Pakistani parents. Most of these families contained more than one consanguineous union, resulting in a mean inbreeding coefficient for their children of 0.0686. It is estimated that 60% of the mortality and severe morbidity of this group of children could be eliminated if inbreeding ceased. However consanguinity is much favoured in this minority group, and health education will have to be carefully and sensitively handled.

Why do UK-born Pakistani babies have high perinatal and neonatal mortality rates?

A prospective study of 4934 babies of different ethnic groups has confirmed the high perinatal mortality rate for Pakistanis and has shown that this was not due to a reluctance to terminate a fetus who is known to be seriously malformed. The major cause of early mortality was a high rate of lethal malformations, which occurred in about 1 in 100 Pakistani babies and which accounted for about half of their perinatal mortality. Many of these were autosomal recessive and occurred only in the offspring of consanguineous parents. However, there was also an excess of lethal cardiac malformations which were not associated with parental consanguinity. The remainder of the excess perinatal mortality was probably due to socio-economic factors. These causes are partly amenable to preventive measures, such as the referral of Pakistani women for expert ultrasonography at 18 to 20 weeks of pregnancy.

Race, consanguinity and social features in Birmingham babies: a basis for prospective study

STUDY OBJECTIVE

The aim of the study was to investigate the influence of consanguinity on children's health.

DESIGN

The study is a prospective survey from birth to five years of a cohort of babies born in a multiracial community. This report details the initial findings on consanguinity.

SETTING

Participating families live predominantly in three health districts of Birmingham, and were recruited in three local maternity hospitals.

PARTICIPANTS

Babies of 2432 European mothers, 509 Afro-Caribbean mothers, 625 Indian mothers, 956 Pakistani mothers, and 216 Bangladeshi mothers have been enrolled in the study. Eighty mothers refused to participate.

MEASUREMENTS AND RESULTS

Sociodemographic information was obtained using a structured questionnaire administered at interview. Interview data were supplemented with obstetric information from the medical records. The highest prevalence of parental consanguinity was in Pakistani Muslims (69%), whereas in Muslims from other countries it was 23%, and it was less than 1% in non-Muslims. In the majority of consanguineous Muslim pedigrees the degree of inbreeding was greater than that for first cousin parents.

CONCLUSIONS

This prospective study will allow an assessment to be made about any ill health in childhood arising from parental consanguinity, about whether screening programmes are indicated for particular autosomal recessive diseases, and about whether premarital health education might be beneficial. The study has also documented parental ages in different races and this, together with the levels of parental consanguinity in all races, will be useful in genetic methods for assessing the frequency of recessive genes, the possibility of genetic heterogeneity, and whether or not parental age effect exists for new mutations of specific genetic disorders.