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Introduction: Veno-venous extracorporeal membrane oxygenation (VV ECMO) improves hypoxemia and carbon dioxide clearance in patients with severe respiratory derangements. A greater understanding of the potential benefits of VV ECMO in trauma patients could lead to broader adoption. We hypothesize that trauma patients who receive VV ECMO have improved mortality outcomes when compared to those receiving conventional ventilator management given the rapid stabilization VV ECMO promotes., Methods: We performed a single center, propensity score matched cohort study. All trauma patients from January 1, 2014, to October 30, 2023, who were placed on VV ECMO or who would have met institutional guidelines for VV ECMO but were managed with conventional ventilator strategies were matched 1:1. The primary outcome analysis was survival at hospital discharge. Significance was defined as p < 0.05., Results: Eighty-one trauma VV ECMO patients and 128 patients who received conventional management met criteria for inclusion. After matching, VV ECMO and conventional treatment cohort characteristics were similar in age and MOI. Matched ISS, SI, lactate levels, and frequency of TBI were also similar. Finally, respiratory parameters including pre-intervention, pH, partial pressure of carbon dioxide (PaCO2), lactate levels, and oxygen saturation were similar between matched groups. VV ECMO patients had higher survival rates at discharge when compared to the matched conventional treatment group (70% v 41%, p < 0.001). Corresponding hazard ratio for VV ECMO use was 0.31 (95%CI 0.18-0.52; p < 0.001). The odds ratio of mortality in matched trauma patients who receive VV ECMO versus conventional treatment was 0.29 (95%CI 0.14-0.58; p < 0.001)., Conclusion: VV ECMO may represent a safe, alternative treatment approach for appropriately screened trauma patients with acute respiratory failure, however further studies are warranted., Competing Interests: All work was performed at the R Adams Cowley Shock Trauma Center at the University of Maryland Medical Center. No funding was used to accomplish this research. The authors report no conflict of interest., (Copyright © 2024 by the Shock Society.)

Traumatic injury is associated with several pulmonary complications, including pulmonary contusion, transfusion-related acute lung injury (TRALI), and the development of acute respiratory distress syndrome (ARDS). There is a lack of literature on these patients supported with veno-venous extracorporeal oxygenation (VV ECMO). Understanding the safety of using VV ECMO to support trauma patients and the ability to hold anticoagulation is important to broaden utilization. This is a single-center retrospective cohort study of adult trauma patients cannulated for VV ECMO during their initial admission over an 8 year period (2014-2021). We hypothesize that anticoagulation can be held in trauma patients on VV ECMO without increasing mortality or prothrombotic complications. We also describe the coagulopathy of traumatically injured patients on VV ECMO. Withholding anticoagulation was not associated with mortality in our study population, and there were no significant differences in bleeding or clotting complications between patients who did and did not receive systemic anticoagulation. Patients in the nonsurvivor group had increased coagulopathy both pre- and post-cannulation. Our study suggests anticoagulation can be safely withheld in traumatically injured VV ECMO patients without increasing mortality, complication rates, or transfusion requirements. Future, multicenter prospective studies with larger sample sizes are required to confirm our results., Competing Interests: Disclosure: The authors have no conflicts of interest to report., (Copyright © ASAIO 2024.)

Background: As the pandemic progressed, the use of extracorporeal membrane oxygenation (ECMO) for COVID-19-related acute respiratory distress syndrome increased, and patient triage and transfer to ECMO centers became important to optimize patient outcomes. Our objectives are to identify predictors of patient transfer for veno-venous extracorporeal membrane oxygenation (V-V ECMO) evaluation as well as to describe the outcomes of accepted patients., Methods: This is a single-center, retrospective analysis of V-V ECMO transfer requests for adult patients with known or suspected COVID-19 and respiratory failure from March 2020 until March 2021. Data were collected prospectively during the triage process for transfer requests as part of clinical patient care at our institution., Results: Of 341 referred patients, 112 (33%) were accepted for transfer to our facility, whereas 229 (67%) patients were declined for transfer. The Classification and Regression Tree analysis showed that patients' high pressure during airway pressure release ventilation (APRV) and age were the variables most significantly associated with the decision to accept or decline patients for transfer., Conclusions: Our triage process enabled one-third of referred patients to be transferred for evaluation, with nearly 70% of those patients ultimately receiving ECMO support. High ventilator settings on APRV and young age were associated with acceptance for transfer. Accepted patients also had a higher incidence of adjunctive therapies (proning and paralysis) prior to transfer request, less cardiac or renal dysfunction, and a shorter duration of mechanical ventilation. Further research is warranted to investigate the outcomes of nontransferred patients., (© 2024 International Center for Artificial Organ and Transplantation (ICAOT) and Wiley Periodicals LLC.)

Introduction: Massive pulmonary embolism (MPE) is a rare but highly fatal condition. Our study's objective was to evaluate the association between advanced interventions and survival among patients with MPE treated with venoarterial extracorporeal membrane oxygenation (VA-ECMO)., Methods: This is a retrospective review of the Extracorporeal Life Support Organization (ELSO) registry data. We included adult patients with MPE who were treated with VA-ECMO during 2010-2020. Our Primary outcome was survival to hospital discharge; secondary outcomes were ECMO duration among survivors and rates of ECMO-related complications. Clinical variables were compared using the Pearson chi-square and Kruskal-Wallis H tests., Results: We included 802 patients; 80 (10%) received SPE and 18 (2%) received CDT. Overall, 426 (53%) survived to discharge; survival was not significantly different among those treated with SPE or CDT on VA-ECMO (70%) versus VA-ECMO alone (52%) or SPE or CDT before VA-ECMO (52%). Multivariable regression found a trend towards increased survival among those treated with SPE or CDT while on ECMO (AOR 1.8, 95% CI 0.9-3.6), but no significant correlation. There was no association between advanced interventions and ECMO duration among survivors, or rates of ECMO-related complications., Conclusion: Our study found no difference in survival in patients with MPE who received advanced interventions prior to ECMO, and a slight non-significant benefit in those who received advanced interventions while on ECMO., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Veno-venous extracorporeal membrane oxygenation (VV ECMO) is a low-frequency, high-intensity procedure used for severe lung illness or injury to facilitate rapid correction of hypoxemia and respiratory acidosis. This technology is more portable and extracorporeal support is more frequently performed outside of the hospital. Future conflicts may require prolonged causality care and more specialized critical care capabilities including VV ECMO to improve patient outcomes. We used an expert consensus survey based on a developed bifemoral VV ECMO cannulation checklist with an operational focus to establish a standard for training, validation testing, and sustainment., Methods: A 36-item procedural checklist was provided to 14 experts from multiple specialties. Using the modified Delphi method, the checklist was serially modified based on expert feedback., Results: Three rounds of the study were performed, resulting in a final 32-item checklist. Each item on the checklist received at least 70% expert agreement on its inclusion in the final checklist., Conclusion: A procedural performance checklist was created for bifemoral VV ECMO using the modified Delphi method. This is an objective tool to assist procedural training and validation for medical providers performing VV ECMO in austere environments.

Background: Venovenous extracorporeal membrane oxygenation (VV ECMO) can support trauma patients with severe respiratory failure. Use in traumatic brain injury (TBI) may raise concerns of worsening complications from intracranial bleeding. However, VV ECMO can rapidly correct hypoxemia and hypercarbia, possibly preventing secondary brain injury. We hypothesize that adult trauma patients with TBI on VV ECMO have comparable survival with trauma patients without TBI., Methods: A single-center, retrospective cohort study involving review of electronic medical records of trauma admissions between July 1, 2014, and August 30, 2022, with discharge diagnosis of TBI who were placed on VV ECMO during their hospital course was performed., Results: Seventy-five trauma patients were treated with VV ECMO; 36 (48%) had TBI. Of those with TBI, 19 (53%) had a hemorrhagic component. Survival was similar between patients with and without a TBI (72% vs. 64%, p = 0.45). Traumatic brain injury survivors had a higher admission Glasgow Coma Scale (7 vs. 3, p < 0.001) than nonsurvivors. Evaluation of prognostic scoring systems on initial head computed tomography demonstrated that TBI VV ECMO survivors were more likely to have a Rotterdam score of 2 (62% vs. 20%, p = 0.03) and no survivors had a Marshall score of ≥4. Twenty-nine patients (81%) had a repeat head computed tomography on VV ECMO with one incidence of expanding hematoma and one new focus of bleeding. Neither patient with a new/worsening bleed received anticoagulation. Survivors demonstrated favorable neurologic outcomes at discharge and outpatient follow-up, based on their mean Rancho Los Amigos Scale (6.5; SD, 1.2), median Cerebral Performance Category (2; interquartile range, 1-2), and median Glasgow Outcome Scale-Extended (7.5; interquartile range, 7-8)., Conclusion: In this series, the majority of TBI patients survived and had good neurologic outcomes despite a low admission Glasgow Coma Scale. Venovenous extracorporeal membrane oxygenation may minimize secondary brain injury and may be considered in select patients with TBI., Level of Evidence: Prognostic and Epidemiological; Level IV., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: VV ECMO is increasingly used as a rescue strategy for hypercarbic and hypoxic respiratory failure refractory to conventional management, and more than 14,000 patients with COVID-19 related respiratory failure have been supported with VV ECMO to date. One of the known complications of VV ECMO support is the development of cannula-associated deep vein thromboses (CaDVT). The purpose of this study was to identify the incidence of CaDVT in COVID-19 patients supported with VV ECMO as compared to non-COVID-19 patients. We hypothesized that due to the hypercoagulable state and longer duration of VV ECMO support required for patients with COVID-19, a higher incidence of CaDVT would be observed in these patients., Methods: This is a single center, retrospective observational study. About 291 non-trauma adult patients who were cannulated for VV ECMO and managed at our institution from January 1, 2014 to January 10, 2022 were included. The primary outcome was the presence of CaDVT 24 h after decannulation in COVID-19 versus non-COVID-19 patients. Our secondary outcome was continued presence of DVT on follow up imaging. CaDVT were defined as venous thrombi detected at prior cannulation sites., Results: Both groups had a high incidence of CaDVT. There was no significant difference in the incidence of CaDVT in COVID-19 patients compared to non-COVID-19 patients (95% vs 88%, p  = 0.13). Patients with COVID-19 had an increased incidence of persistent CaDVT on repeat imaging (78% vs 56%, p  = 0.03)., Conclusion: Given the high number of post-decannulation CaDVT in both groups, routine screening should be a part of post ECMO care in both populations. Repeat venous duplex ultrasound should be performed to assess for the need for ongoing treatment given the high incidence of CaDVT that persisted on repeat duplex scans., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: The PREdiction of Survival on ECMO Therapy Score (PRESET-Score) predicts mortality while on veno-venous extracorporeal membrane oxygenation (VV ECMO) for acute respiratory distress syndrome. The aim of our study was to assess the association between PRESET-Score and survival in a large COVID-19 VV ECMO cohort., Methods: This was a single-center retrospective study of COVID-19 VV ECMO patients from 15 March 2020, to 30 November 2021. Univariable and Multivariable analyses were performed to assess patient survival and score differences., Results: A total of 105 patients were included in our analysis with a mean PRESET-Score of 6.74. Overall survival was 65.71%. The mean PRESET-Score was significantly lower in the survivor group (6.03 vs 8.11, p < 0.001). Patients with a PRESET-Score less than or equal to six had improved survival compared to those with a PRESET-Score greater than or equal to 8 (97.7% vs. 32.5%, p < 0.001). In a multivariable logistic regression, a lower PRESET-Score was also predictive of survival (OR 2.84, 95% CI 1.75, 4.63, p < 0.001)., Conclusion: We demonstrate that lower PRESET scores are associated with improved survival. The utilization of this validated, quantifiable, and objective scoring system to help identify COVID-19 patients with the greatest potential to benefit from VV-ECMO appears feasible. The incorporation of the PRESET-Score into institutional ECMO candidacy guidelines can help insure and improve access of this limited healthcare resource to all critically ill patients., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: With the increased demand for veno-venous extracorporeal membrane oxygenation (VV ECMO) during the COVID-19 pandemic, guidelines for patient candidacy have often limited this modality for patients with a body mass index (BMI) less than 40 kg/m 2 . We hypothesize that COVID-19 VV ECMO patients with at least class III obesity (BMI ≥ 40) have decreased in-hospital mortality when compared to non-COVID-19 and non-class III obese COVID-19 VV ECMO populations., Methods: This is a single-center retrospective study of COVID-19 VV ECMO patients from January 1, 2014, to November 30, 2021. Our institution used BMI ≥ 40 as part of a multi-disciplinary VV ECMO candidate screening process in COVID-19 patients. BMI criteria were not considered for exclusion criteria in non-COVID-19 patients. Univariate and multivariable analyses were performed to assess in-hospital mortality differences., Results: A total of 380 patients were included in our analysis: The COVID-19 group had a lower survival rate that was not statistically significant (65.7% vs.74.9%, p = .07). The median BMI between BMI ≥ 40 COVID-19 and non-COVID-19 patients was not different (44.5 vs 45.5, p = .2). There was no difference in survival between the groups (73.3% vs. 78.5%, p = .58), nor was there a difference in survival between the COVID-19 BMI ≥ 40 and BMI < 40 patients (73.3, 62.7, p = .29). Multivariable logistic regression with the outcome of in-hospital mortality was performed and BMI was not found to be significant (OR 0.99, 95% CI 0.89, 1.01; p = .92)., Conclusion: BMI ≥ 40 was not an independent risk factor for decreased in-hospital survival in this cohort of VV ECMO patients at a high-volume center. BMI should not be the sole factor when deciding VV ECMO candidacy in patients with COVID-19.

Background: Venovenous extracorporeal membrane oxygenation (VV ECMO) is used for respiratory failure when standard therapy fails. Optimal trauma care requires patients be stable enough to undergo procedures. Early VV ECMO (EVV) to stabilize trauma patients with respiratory failure as part of resuscitation could facilitate additional care. As VV ECMO technology is portable and prehospital cannulation possible, it could also be used in austere environments. We hypothesize that EVV facilitates injury care without worsening survival., Methods: Our single center, retrospective cohort study included all trauma patients between January 1, 2014, and August 1, 2022, who were placed on VV ECMO. Early VV was defined as cannulation ≤48 hours from arrival with subsequent operation for injuries. Data were analyzed with descriptive statistics. Parametric or nonparametric statistics were used based on the nature of the data. After testing for normality, significance was defined as a p < 0.05. Logistic regression diagnostics were performed., Results: Seventy-five patients were identified and 57 (76%) underwent EVV. There was no difference in survival between the EVV and non-EVV groups (70% vs. 61%, p = 0.47). Age, race, and gender did not differ between EVV survivors and nonsurvivors. Time to cannulation (4.5 hours vs. 8 hours, p = 0.39) and injury severity scores (34 vs. 29, p = 0.74) were similar. Early VV survivors had lower lactic acid levels precannulation (3.9 mmol/L vs. 11.9 mmol/L, p < 0.001). A multivariable logistic regression analysis examining admission and precannulation laboratory and hemodynamic values demonstrated that lower precannulation lactic acid levels predicted survival (odds ratio, 1.2; 95% confidence interval, 1.02-1.5; p = 0.03), with a significant inflection point of 7.4 mmol/L corresponding to decreased survival at hospital discharge., Conclusion: Patients undergoing EVV did not have increased mortality compared with the overall trauma VV ECMO population. Early VV resulted in ventilatory stabilization that allowed subsequent procedural treatment of injuries., Level of Evidence: Therapeutic Care/Management; Level III., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Venovenous extracorporeal membrane oxygenation (VV ECMO) has been used to treat severe coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome; however, patient selection criteria have evolved throughout the pandemic. In this study, we sought to determine the association of patient mortality with time from positive COVID-19 test and infiltrate on chest radiograph (x-ray) to VV ECMO cannulation. We hypothesized that an increasing duration between a positive COVID-19 test or infiltrates on chest x-ray and cannulation would be associated with increased mortality. This is a single-center retrospective chart review of COVID-19 VV ECMO patients from March 1, 2020 to July 28, 2021. Unadjusted and adjusted multivariate analyses were performed to assess for mortality differences. A total of 93 patients were included in our study. Increased time, in days, from infiltrate on chest x-ray to cannulation was associated with increased mortality in both unadjusted (5-9, P = 0.002) and adjusted regression analyses (odds ratio [OR]: 1.49, 95% CI: 1.22-1.81, P < 0.01). Time from positive test to cannulation was not found to be significant between survivors and nonsurvivors (7.5-11, P = 0.06). Time from infiltrate on chest x-ray to cannulation for VV ECMO should be considered when assessing patient candidacy. Further larger cohort and prospective studies are required., Competing Interests: Disclosure: The authors have no conflicts of interest to report., (Copyright © ASAIO 2022.)

Objectives: To explore whether precannulation international normalized ratio (INR) is associated with in-hospital mortality in venoarterial extracorporeal membrane oxygenation (VA-ECMO) patients., Design: A retrospective, observational cohort study., Setting: A quaternary care academic medical center., Participants: Patients with cardiogenic shock on VA-ECMO for >24 hours., Interventions: None, observational study., Measurements and Main Results: A total of 188 patients who were on VA-ECMO were included over three years. Patients were stratified into three groups based on their pre-ECMO INR: INR <1.5, INR 1.5 to 1.8, and INR >1.8. For all patients, demographics, comorbidities, and ECMO details were recorded. The study's primary outcome was in-hospital mortality and secondary outcomes included major bleeding, minor bleeding, allogeneic transfusion, ischemic stroke, intracranial hemorrhage, acute renal failure, acute liver failure, gastrointestinal bleeding, intensive care unit and hospital lengths of stay. A multivariate logistic regression was used to determine whether precannulation INR was associated independently with in-hospital mortality. In-hospital mortality differed significantly by INR group (51.6% INR >1.8 v 42.3% INR 1.5-1.8 v 24.3% INR <1.5; p = 0.004). In a multivariate logistic regression model, precannulation INR >1.8 was associated independently with an increased odds of mortality (odds ratio, 2.48; 95% confidence interval, 1.05-6.04) after controlling for sex, Survival after VA- ECMO score, and ECMO indication. An INR within 1.5 to 1.8 did not confer an increased mortality risk., Conclusions: An INR >1.8 before VA-ECMO cannulation is associated independently with in-hospital mortality. Precannulation INR should be considered by clinicians so that ECMO resources can be better allocated and risks of organ failure and intracranial hemorrhage can be better understood., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background : Prehospital intubation success is routinely treated as a dichotomous outcome based on an endotracheal tube passing through vocal cords regardless of number of attempts or occurrence of hypoxia, or hypotension, which are associated with worse outcomes. We explore patient, provider, and procedure-related variables associated with successful definitive airway sans hypoxia/hypotension on first attempt (DASH-1A) in traumatically injured subjects undergoing endotracheal intubation at the scene of injury by a helicopter EMS system. Methods : This single-center retrospective chart review included patients with traumatic injuries and at least one attempted intubation by helicopter EMS at the scene of injury. Demographic and clinical variables were tested for association with DASH-1A and overall first-attempt success using univariate comparisons and multivariable logistic regression to produce adjusted odds ratios (aORs) and 95% confidence intervals (CIs). Purposeful backwards stepwise elimination was used to develop logistic regression models for outcomes. Initial inclusion of covariates in multivariable models was based on clinical judgement, known or suspected risk factors and confounders for intubation success, and univariate associations. Results : Of 419 subjects screened, 263 met inclusion criteria. Median age was 34 years and the majority of subjects were Caucasian (95%), male (76%), and suffered blunt trauma (90%). The endotracheal tube was successfully placed on the first attempt in 198 (75.3%) of patients, but only 142 (55.3%) had a successful DASH-1A, and overall, 246 (94%) had an endotracheal tube passed successfully before hospital arrival. Factors significantly associated with successful DASH-1A were no ground EMS intubation attempt prior to arrival [aOR 2.2 (CI 1.0-4.9)], lack of airway secretions/blood [1.9 (1.0-3.4)], Cormack-Lehane Score of I and II [12.3 (4.5-33.2) & 3.2 (1.2-9.1), respectively], and bougie use [5.4 (1.8-15.8)]. For endotracheal tube passing only, the following were significantly associated with first pass success: grade of view I and II [aORs 87.3 (CI 25.8-295.7) & 6.8 (2.3-19.5), respectively], lack of secretions/blood [4.9 (2.1-11.2), bougie use [7.8 (2.3-26.3)], direct laryngoscopy [5.1 (1.5-17.0)] and not using apneic oxygenation through a nasal cannula [2.5 (1.1-5.6)]. Conclusion : In our helicopter EMS system, successful endotracheal intubation on the first attempt and without an episode of hypoxia was associated with no ground EMS intubation attempt prior to flight crew arrival, lack of airway secretions/blood, Cormack-Lehane Score, and bougie use.

Background: Hemorrhage is a leading cause of death in traumatically injured patients. Currently, the importance of earlier administration of packed red blood cells (pRBC) to improve outcomes is limited. We evaluated the association of earlier pRBC administration and mortality when compared with later transfusion initiation., Methods: This single-center retrospective cohort study of trauma patients transported by a single helicopter service from the scene of injury to an urban academic trauma center included patients receiving at least one unit of pRBC within 24 hours of hospital arrival. The final cohort included patients transported to the trauma center between March 11, 2010, and October 30, 2013. The helicopter service carries two units of pRBC for protocol-driven prehospital transfusion. Logistic regression was used to model odds of death, and 95% confidence intervals were calculated., Results: The 94 patients meeting inclusion criteria had a mean (SD) age of 43 (19) years; 87 (93%) of 94 were white, 66 (70%) of 94 were male, and 88(94%) of 94 sustained blunt force injuries. Median Injury Severity Score was 29 (range, 2-75), and 31 (33%) of 94 died within 30 days. Most patients [82/94 (87%)] received their first pRBC transfusion during transport or within one hour of arrival at the emergency department (ED). For the 82 patients receiving a first pRBC transfusion within one hour of ED arrival, each 10-minute increase in time to transfusion increased the odds of death [OR, 1.27 (95% CI, 1.01-1.62; p = 0.044)], controlling for TRISS. At 30 days, 29/82 (35%) patients who received a pRBC transfusion within one hour of ED arrival, and 2 (16%) of 12 patients who received delayed transfusion were deceased (difference, 19%; 95% CI, -5% to 42%)., Conclusion: In this study, delays in time to pRBC administration of as short as 10 minutes were associated with increased odds of death for patients receiving ultra-early pRBC transfusion. Expedient prehospital and ED transfusion capabilities may improve outcomes after trauma., Level of Evidence: Therapeutic/care management study, level III.

Interleukin-1 stimulated bovine nasal cartilage fragments were cultured in the presence and absence of various metalloproteinase inhibitors. Tissue inhibitor of metalloproteinases (TIMP) and tissue inhibitor of metalloproteinases-2 (TIMP-2) completely blocked the release of collagen from the cartilage but were unable to prevent the release of proteoglycan. Similarly, a low molecular weight synthetic inhibitor (BB87) inhibited collagen release in a dose dependent manner, but was unable to inhibit proteoglycan release at the same concentrations. Significantly greater concentrations of inhibitor than those required to block collagen release did, however, block proteoglycan release. These results indicate that the therapeutic use of naturally occurring or synthetic inhibitors may provide a means of modifying the destruction of connective tissue proteins occurring in the arthritides and other connective tissue pathologies.

Objective: To determine the levels in serum of tissue inhibitor of metalloproteinases (TIMP) in pregnancy and to examine the possibility of a time course in relation to parturition, both term and preterm., Methods: Serum tissue inhibitor of metalloproteinases was measured using an enzyme-linked immunosorbent assay. A cross-sectional study was conducted in 333 women during pregnancy, labor, and the postpartum period and in 27 nonpregnant volunteers. Longitudinal data were obtained from 22 women who provided a sample at term, during labor, and in the postpartum period., Results: In uncomplicated pregnancies, serum TIMP levels were low from the onset of pregnancy until 37 weeks' gestation, in comparison to levels in nonpregnant women (P < .001). During the final weeks of pregnancy, levels rose and at 37-42 weeks were similar to nonpregnant levels. The levels did not change with the onset of labor. Serum concentrations of TIMP obtained during preterm labor were elevated compared to a control group of patients at a similar gestation who subsequently delivered at term (P < .01). Serum TIMP levels were significantly higher during the postpartum period than at all other times (P < .001)., Conclusions: Changes in serum TIMP levels during and after pregnancy may parallel the remodeling of the extracellular matrix that takes place throughout this period. Further work is necessary to evaluate the prognostic value of TIMP for preterm labor.

Serum levels of tissue collagenase, matrix metalloproteinase-1, were measured in both longitudinal and cross-sectional studies, in 332 pregnant women and 27 non-pregnant volunteers. The enzyme-linked immunosorbent assay (ELISA) used is the first described to measure collagenase in serum directly, is specific, and is rapid and reproducible. Levels were determined throughout pregnancy, during term and preterm labour, and in the post-partum period. Serum tissue collagenase levels were elevated in pregnancy (P < 0.001). There was no difference between levels of serum collagenase prior to labour at term and those observed during labour. Similarly, there was no significant difference in levels obtained during preterm labour and those at a similar gestation in women who subsequently delivered at term. No significant decrease in levels had occurred by the 4th post-partum day. In view of these findings of unaltered matrix metalloproteinase-1 levels in association with labour, previous reports of raised serum collagenase activity in association with the onset of spontaneous labour, at term and preterm gestation periods, may be due to increased neutrophil collagenase activity.