Direct peritoneal resuscitation from hemorrhagic shock: effect of time delay in therapy initiation

Evaluating the effectiveness and outcomes associated with direct peritoneal resuscitation in damage control surgery patients with and without hemorrhagic shock

INTRODUCTION

This narrative review aims to evaluate the efficacy of adjunct direct peritoneal resuscitation (DPR) in the treatment of adult damage control surgery (DCS) patients both with and without hemorrhagic shock, and its impact on associated outcomes.

METHODS

PubMed, Google Scholar, EMBASE, ProQuest, and Cochrane were searched for relevant articles published through April 13th, 2023. Studies assessing the utilization of DPR in adult DCS patients were included. Outcomes included time to abdominal closure, intra-abdominal complications, in-hospital mortality, and ICU length of stay (ICU LOS).

RESULTS

Five studies evaluating 437 patients were included. In patients with hemorrhagic shock, DPR was associated with reduced time to abdominal closure (DPR 4.1 days, control 5.9 days, p = 0.002), intra-abdominal complications including abscess formation (DPR 27 %, control 47 %, p = 0.04), and ICU LOS (DPR 8 days, control 11 days, p = 0.004). Findings in patients without hemorrhagic shock were conflicting. Closure times were decreased in one study (DPR 5.9 days, control 7.7 days, p < 0.02) and increased in another study (DPR 3.5 days, control 2.5 days, p = 0.02), intra-abdominal complications were decreased in one study (DPR 27 %, control 47 %, p = 0.04) and similar in another, and ICU LOS was decreased in one study (DPR 17 days, control 24 days, p < 0.002) and increased in another (DPR 13 days, control 11.4 days, p = 0.807).

CONCLUSION

In patients with hemorrhagic shock, adjunct DPR is associated with reduced time to abdominal closure, intra-abdominal complications such as abscesses, fistula, bleeding, anastomotic leak, and ICU LOS. Utilization of DPR in patients without hemorrhagic shock showed promising but inconsistent findings.

Direct Peritoneal Resuscitation in Trauma Patients Results in Similar Rates of Intra-Abdominal Complications

Background: Trauma patients undergoing damage control surgery (DCS) have a propensity for complicated abdominal closures and intra-abdominal complications. Studies show that management of open abdomens with direct peritoneal resuscitation (DPR) reduces intra-abdominal complications and accelerates abdominal closure. This novel study compares intra-abdominal complication rates and the effect of DPR initiation in patients who received DPR and those who did not. Patients and Methods: A retrospective chart review was performed on 120 patients who underwent DCS. Fifty patients were identified as DCS with DPR, and matched to 70 controls by gender, race, age, body mass index (BMI), past medical history, mechanism of trauma, and injury severity score. Results: The two groups of patients, those without DPR (-DPR) and those with DPR (+DPR), were similar in their characteristics. The +DPR group was more likely to have a mesh closure than the -DPR (14% and 3%; p = 0.022). The +DPR group took longer to have a final closure (3.5 ± 2.6 days vs. 2.5 ± 1.8; p = 0.020). Infection complications and mechanical failure of the closure technique were similar among the two groups. Timing of DPR initiation had no effect on closure type but did statistically increase the number of days to closure (initiation at first operation 2.8 ± 1.8 days vs. initiation at subsequent operations 6.0 ± 3.3 days; p ≤ 0.001). Conclusions: The use of DPR did not result in different outcomes in trauma patients. Therefore, traditional resuscitative measures for DCS may not be inferior to DCS with DPR. When choosing to use DPR, initiating it at the first operation could reduce the number of days to closure.

Physiology of Human Hemorrhage and Compensation

Hemorrhage is a leading cause of death following traumatic injuries in the United States. Much of the previous work in assessing the physiology and pathophysiology underlying blood loss has focused on descriptive measures of hemodynamic responses such as blood pressure, cardiac output, stroke volume, heart rate, and vascular resistance as indicators of changes in organ perfusion. More recent work has shifted the focus toward understanding mechanisms of compensation for reduced systemic delivery and cellular utilization of oxygen as a more comprehensive approach to understanding the complex physiologic changes that occur following and during blood loss. In this article, we begin with applying dimensional analysis for comparison of animal models, and progress to descriptions of various physiological consequences of hemorrhage. We then introduce the complementary side of compensation by detailing the complexity and integration of various compensatory mechanisms that are activated from the initiation of hemorrhage and serve to maintain adequate vital organ perfusion and hemodynamic stability in the scenario of reduced systemic delivery of oxygen until the onset of hemodynamic decompensation. New data are introduced that challenge legacy concepts related to mechanisms that underlie baroreflex functions and provide novel insights into the measurement of the integrated response of compensation to central hypovolemia known as the compensatory reserve. The impact of demographic and environmental factors on tolerance to hemorrhage is also reviewed. Finally, we describe how understanding the physiology of compensation can be translated to applications for early assessment of the clinical status and accurate triage of hypovolemic and hypotensive patients. © 2021 American Physiological Society. Compr Physiol 11:1531-1574, 2021.

Direct Peritoneal Resuscitation: A Novel Adjunct to Damage Control Laparotomy

Direct peritoneal resuscitation is a validated resuscitation strategy for patients undergoing damage control surgery for hemorrhage, sepsis, or abdominal compartment syndrome with open abdomen and planned reexploration after a period of resuscitation in the intensive care unit. Direct peritoneal resuscitation can decrease visceral edema, normalize body water ratios, accelerate primary abdominal wall closure after damage control surgery, and prevent complications associated with open abdomen. This review article describes the physiological benefits of direct peritoneal resuscitation, how this technique fits within management priorities for the patient in shock, and procedural components in the care of open abdomen surgical patients receiving direct peritoneal resuscitation. Strategies for successful implementation of a novel multidisciplinary intervention in critical care practice are explored.

LCTX-F2, a Novel Potentiator of Coagulation Factors From the Spider Venom of Lycosa singoriensis

Spider venoms contain many functional proteins/peptides such as proteinases, serine/cysteine proteinase inhibitors, insecticidal toxins, and ion channel toxins. However, to date, no peptide toxin with procoagulant activities has been identified from spider venom. In this study, a novel toxin LCTX-F2 with coagulation-promoting activity was identified and characterized in the venom of the spider Lycosa singoriensis (L. singoriensis). LCTX-F2 significantly shortened activated partial thromboplastin time (APTT), clotting time, and plasma recalcification time. This toxin directly interacted with several coagulation factors such as FXIIa, kallikrein, thrombin, and FXa and increased their protease activities. In liver bleeding and tail bleeding mouse models, LCTX-F2 significantly decreased the number of blood cells and bleeding time in a dose-dependent manner. At the same dosage, LCTX-F2 exhibited a more significant procoagulant effect than epsilon aminocaproic acid (EACA). Moreover, LCTX-F2 showed no cytotoxic or hemolytic activity against either normal cells or red blood cells. Our results suggested that LCTX-F2 is a potentiator of coagulation factors with the potential for use in the development of procoagulant drugs.

Effect of peritoneal dialysis solution with different pyruvate concentrations on intestinal injury

To investigate the effects of direct peritoneal resuscitation with pyruvate-peritoneal dialysis solution (Pyr-PDS) of different concentrations combined with intravenous resuscitation on acid–base imbalance and intestinal ischemia reperfusion injury in rats with hemorrhagic shock. Sixty rats were randomly assigned to group SHAM, group intravenous resuscitation, and four direct peritoneal resuscitation groups combined with intravenous resuscitation: group NS, LA, PY1, and PY2, that is, normal saline, lactate-PDS (Lac-PDS), lower concentration Pyr-PDS (Pyr-PDS1), and higher concentration Pyr-PDS (Pyr-PDS2), respectively. Two hours after hemorrhagic shock and resuscitation, the pH, oxygen partial pressure, carbon dioxide partial pressure (PCO2), base excess, and bicarbonate ion concentration (HCO3−) of the arterial blood were measured. The intestinal mucosal damage index and intercellular adhesion molecule 1 (ICAM-1), tumor necrosis factor-α, interleukin-6, zonula occludens-1, claudin-1, and occludin levels in intestinal issues were detected. Two hours after resuscitation, group PY2 had higher mean arterial pressure, pH, oxygen partial pressure, and base excess and lower PCO2of arterial blood than group PY1 ( P <  0.05). Tumor necrosis factor-α and interleukin-6 levels in group PY2 were significantly lower than those in group PY1 ( P <  0.05). Zonula occludens-1, claudin-1, and occludin expression levels were significantly higher in group PY2 than in group PY1 ( P <  0.05). Direct peritoneal resuscitation with Pyr-PDS2 combined with intravenous resuscitation enhanced the hemodynamics, improved the acid–base balance, and alleviated intestinal ischemia reperfusion injury from hemorrhagic shock and resuscitation in rats. The mechanisms might include correction of acidosis, inhibition of inflammatory response, enhancement of systemic immune status, regulation of intestinal epithelial permeability, and maintenance of intestinal mucosal barrier function.

Impact statement

Hemorrhagic shock is a life-threatening condition after trauma or during surgery. Acid–base imbalance and intestinal ischemia reperfusion injury are two significant causes in the pathogenetic process and multiple organ dysfunction. As a result, it is urgent and necessary to find an effective method of resuscitation in order to reverse the acid–base imbalance and protect organ function. This current study confirmed the protection against hypoxic acidosis and intestinal ischemia reperfusion injury by peritoneal resuscitation with pyruvate combined with intravenous resuscitation in rats with hemorrhagic shock. And the peritoneal dialysis solution with pyruvate of high concentration plays a crucial role in the process. It provided a new idea and possible direction of fluid resuscitation for alleviating organ injuries, protecting organ functions, and improving clinical prognosis after hemorrhagic shock and resuscitation.

Pyruvate Protects Against Intestinal Injury by Inhibiting the JAK/STAT Signaling Pathway in Rats With Hemorrhagic Shock

BACKGROUND

This study aimed to investigate the role of Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway in protection by peritoneal resuscitation (PR) using pyruvate-peritoneal dialysis solution (PY-PDS) against intestinal injury from hemorrhagic shock (HS) in rats.

MATERIALS AND METHODS

Sixty-four rats were assigned to eight groups: group SHAM; group intravenous resuscitation (VR); groups NS, LA, and PY in which the rats were subjected to HS and PR with normal saline (NS), lactate-peritoneal dialysis solution (LA-PDS), and PY-PDS, respectively, combined with VR; and groups DMSO, RPM, and AG490 in which the rats were subjected to HS and VR with pretreatment of dimethyl sulfoxide (DMSO), rapamycin (RPM), and tyrphostin B42 (AG490).

RESULTS

At 2 h after HS and resuscitation, the levels of diamine oxidase, 15-F_2t-isoprostane, thromboxane B₂, and endothelin-1, in the blood and the intestinal mucosal apoptotic index and caspase-3 were lower in groups PY, RPM, and AG490 than in groups VR, NS, LA, and DMSO. Group PY showed lower levels of malondialdehyde and myeloperoxidase and a higher level of superoxide dismutase than groups VR, NS, and LA. Phosphorylated JAK2 and phosphorylated STAT3 levels were lower in groups PY, RPM, AG490, and LA than in groups VR, NS, and DMSO.

CONCLUSIONS

The protection mechanism of PR with PY-PDS combined with VR was related to the inhibition of the JAK/STAT signaling pathway during HS and resuscitation. The process might include suppression of oxidative stress, reduction of neutrophil infiltration, regulation of microcirculation, and inhibition of apoptosis.

Hemorrhagic Shock and the Microvasculature

The microvasculature plays a central role in the pathophysiology of hemorrhagic shock and is also involved in arguably all therapeutic attempts to reverse or minimize the adverse consequences of shock. Microvascular studies specific to hemorrhagic shock were reviewed and broadly grouped depending on whether data were obtained on animal or human subjects. Dedicated sections were assigned to microcirculatory changes in specific organs, and major categories of pathophysiological alterations and mechanisms such as oxygen distribution, ischemia, inflammation, glycocalyx changes, vasomotion, endothelial dysfunction, and coagulopathy as well as biomarkers and some therapeutic strategies. Innovative experimental methods were also reviewed for quantitative microcirculatory assessment as it pertains to changes during hemorrhagic shock. The text and figures include representative quantitative microvascular data obtained in various organs and tissues such as skin, muscle, lung, liver, brain, heart, kidney, pancreas, intestines, and mesentery from various species including mice, rats, hamsters, sheep, swine, bats, and humans. Based on reviewed findings, a new integrative conceptual model is presented that includes about 100 systemic and local factors linked to microvessels in hemorrhagic shock. The combination of systemic measures with the understanding of these processes at the microvascular level is fundamental to further develop targeted and personalized interventions that will reduce tissue injury, organ dysfunction, and ultimately mortality due to hemorrhagic shock. Published 2018. Compr Physiol 8:61-101, 2018.

Shock associated with endothelial dysfunction in omental microvessels

BACKGROUND

Impaired microvascular function leads to a poor outcome in a variety of medical conditions. Our aim was to determine whether vasodilator responses to acetylcholine (Ach) are impaired in human omental arterioles from patients with severe trauma.

MATERIALS AND METHODS

Patients with massive blood loss and severe shock requiring damage control procedures were included. Tissues were collected at the first (FEL) and the second explorative laparotomy (SEL). Control tissues were collected from nontrauma patients. Freshly isolated 50-200-μm-diameter omental arterioles were analysed using videomicroscopy. Dihydroethidine and DCF-DA fluorescence were used to assess reactive oxygen species (ROS) production. MnTBAP was used to determine the contribution of excess vascular superoxide contribution to endothelial dysfunction.

RESULTS

After constriction (30-50%) with endothelin-1, dilation to graded doses of Ach (10^-9 -10^-4 M) was greater in control vessels compared to FEL and SEL (max dilation at 10^-4 M (MD) = 25 ± 3%, n = 8; and 59 ± 8%, n = 8, respectively, and controls MD = 93 ± 10%, n = 6, P < 0·05). Fluorescence imaging of ROS production showed significant increases in superoxide (225·46 ± 12·86; 215·77 ± 10·75 vs. 133·75 ± 7·26, arbitrary units; P < 0·05) and peroxide-related ROS (240·8 ± 20·42; 234·59 ± 28·86, vs. 150·78 ± 15·65, arbitrary units; P < 0·05), in FEL and SEL microvessels compared to control, respectively. FEL pretreated with MnTBAP demonstrated significant improvement in Ach-induced vasodilation (25·5 ± 3·0% vs. 79·5 ± 8·2%; P < 0·05).

CONCLUSIONS

Severe shock associated with microvascular endothelial dysfunction enhances production of ROS in human omental tissues. The altered flow regulation may contribute to a mismatch between local blood supply and demand, exacerbating abnormal tissue perfusion and function.

Impact of hemoglobin nitrite to nitric oxide reductase on blood transfusion for resuscitation from hemorrhagic shock

Background:

Transfusion of blood remains the gold standard for fluid resuscitation from hemorrhagic shock. Hemoglobin (Hb) within the red blood cell transports oxygen and modulates nitric oxide (NO) through NO scavenging and nitrite reductase.

Aims:

This study was designed to examine the effects of incorporating a novel NO modulator, RRx-001, on systemic and microvascular hemodynamic response after blood transfusion for resuscitation from hemorrhagic shock in a hamster window chamber model. In addition, to RRx-001 the role of low dose of nitrite (1 × 10⁻⁹ moles per animal) supplementation after resuscitation was studied.

Materials and Methods:

Severe hemorrhage was induced by arterial controlled bleeding of 50% of the blood volume (BV) and the hypovolemic state was maintained for 1 h. The animals received volume resuscitation by an infusion of 25% of BV using fresh blood alone or with added nitrite, or fresh blood treated with RRx-001 (140 mg/kg) or RRx-001 (140 mg/kg) with added nitrite. Systemic and microvascular hemodynamics were followed at baseline and at different time points during the entire study. Tissue apoptosis and necrosis were measured 8 h after resuscitation to correlate hemodynamic changes with tissue viability.

Results:

Compared to resuscitation with blood alone, blood treated with RRx-001 decreased vascular resistance, increased blood flow and functional capillary density immediately after resuscitation and preserved tissue viability. Furthermore, in RRx-001 treated animals, both mean arterial pressure (MAP) and met Hb were maintained within normal levels after resuscitation (MAP >90 mmHg and metHb <2%). The addition of nitrite to RRx-001 did not significantly improve the effects of RRx-001, as it increased methemoglobinemia and lower MAP.

Conclusion:

RRx-001 alone enhanced perfusion and reduced tissue damage as compared to blood; it may serve as an adjunct therapy to the current gold standard treatment for resuscitation from hemorrhagic shock.

Intestinal Microcirculatory Flow Alterations in Necrotizing Enterocolitis are Improved by Direct Peritoneal Resuscitation

Vasoconstriction of the neonatal intestinal microvasculature is a central mechanistic event in development of necrotizing enterocolitis. We hypothesized that topical treatment of the intestine with dialysate fluid would ameliorate the vasoconstriction in necrotizing enterocolitis (NEC). NEC was induced in experimental groups. Control animals were delivered vaginally and dam-fed (control group). Neonatal pups underwent laser Doppler flow study of the terminal ileum to determine real-time blood flow in the intestinal microvasculature. After baseline flow was determined, dialysis solution was added to the peritoneal cavity and alterations in microcirculation were recorded. Baseline ileal blood flow in the control group was significantly higher than in NEC rat pups at 48 hours post delivery ( P < 0.05), but not at 24 hours ( P = NS). Ileal blood flow increased in all groups after adding dialysate ( P < 0.05), improving ileal blood flow in the 48-hour NEC group and reaching the baseline level of the 48-hour control group ( P < 0.05). Our data shows blood flow to be higher in 48-hour controls as compared with 24-hour controls suggesting a time-dependency in the development of intestinal vasoregulatory processes. All groups had an increase in blood flow with dialysate treatment. This may represent a novel initial therapy to improve intestinal ischemia in human necrotizing enterocolitis.

Direct peritoneal resuscitation augments ileal blood flow in necrotizing enterocolitis via a novel mechanism

PURPOSE

Endothelin-1, prostaglandins (PGs), and nitric oxide (NO) have been implicated in the intestinal microvascular dysfunction of necrotizing enterocolitis (NEC). We hypothesized that direct peritoneal resuscitation (DPR) dilates the intestinal microvasculature and improves blood flow independent of these mechanisms.

METHODS

Rat pups were assigned by litter to experimental NEC or CONTROL groups. Laser Doppler flowmetry evaluation of intestinal microvascular blood flow was studied at baseline, with mediator blockade (endothelin-A receptor, endothelin-B receptor, PG synthesis, or NO synthase) and with DPR. Repeated-measures analysis of variance test was applied with Tukey-Kramer honestly significant difference test (P < .05).

RESULTS

At baseline, NEC animals demonstrated significantly decreased ileal blood flow as compared with CONTROLs (P < .05). Endothelin-A receptor and PG inhibition increased flow in the intestinal microvasculature, but this was significantly augmented by the addition of DPR (P < .05). Blockade of NO synthase decreased intestinal blood flow, which was overcome with addition of DPR (P < .05).

CONCLUSION

Ileal blood flow was significantly reduced in NEC animals as compared with CONTROLs. The addition of DPR to the peritoneum increased ileal blood flow significantly in all groups in spite of blockade of these known vasoactive mechanisms. Direct peritoneal resuscitation may be a novel strategy to improve intestinal blood flow in NEC.

The beneficial effect of direct peritoneal resuscitation on septic shock in rats

The high mortality associated with conventionally resuscitated septic shock and the subsequent multiple-organ failure remain a very significant and costly clinical problem. Conventional simple intravenous resuscitation (CR) from septic shock often fails to restore the progressive splanchnic vasoconstriction and hypoperfusion, and fails to reverse gut-derived systemic inflammatory response and fluid sequestration. Numerous interventions have been used to protect organ systems and cellular viability from the lethal injury accompanying hypoperfusion and ischemia but none of these efforts have been sufficient to halt or reverse the main course of the pathophysiology noted with conventional resuscitated shock. Recently, some studies have found that in hemorrhagic shock, direct peritoneal resuscitation (DPR) not only produces sustained hyperperfusion in viscera but also has immunomodulatory and anti-fluid sequestration effects. Although the etiology and pathogenesis of septic shock and hemorrhagic shock differ, both kinds of shock result in hypoperfusion of the intestines and other internal organs. In this paper, we seek to determine whether DPR has a similar therapeutic effect on septic shock/resuscitation.

Preliminary resuscitation for perforated necrotizing enterocolitis: 2 cases treated with initial direct peritoneal resuscitation

We used peritoneal infusions of 2.5% dextrose solution as an adjunct to resuscitation of 2 very low-birth-weight infants having perforated necrotizing enterocolitis. This was repeated every 12 hours for 7 days before and 1 day after extensive bowel resection. The designation of this research method has been termed direct peritoneal resuscitation. We discuss our observations and the evolution of this technique from studies in the animal laboratory to a recent trial in patients with abdominal trauma. We propose that the early response benefit of this preoperative resuscitation seen in our 2 cases be investigated by others. Prospective controlled trials could then be considered for those high-risk patients having diffuse disease and shock.

Screening the Hemostatic Active Fraction of Artemisia annua L. In-vitro

Artemisinin extracted from Artemisia annua L. is the best medicine with the highest efficiency, the most effective and the lowest toxicity in treating ague nowadays. At present, most studies focus on artemisinin and its derivatives, while the study and report about the other active components are rare. This paper purposed to further discover new indication of Artemisia annua L. connecting with the record of traditional medicine. We screened the hemostatic active fraction of Artemisia annua L. in-vitro by plasma recalcification time (PRT). The crude extract and the extract of n-butanol were purified by polyamide, MCI, gel column in order. Determining the part of 20% methanol fraction after column chromatography of MCI gel is the hemostatic active fraction of Artemisia annua L. The shorten rate of clotting time are followed by: crude extract of Artemisin annua L. (8.51%); the n-butanol extract (14.89%); water eluting fraction after the extract of n-butanol was purificated by polyamide (22.11%); 20% methanol fraction after column chromatography of MCI gel (27.37%). It can provide experimental data for the clinical application of Artemisia annua L. which can be exploited as hemostatic. This topic has a certain academic value and potential prospects on the deep research of the Artemisia annua L. resource.

Direct peritoneal resuscitation accelerates primary abdominal wall closure after damage control surgery

BACKGROUND

Damage control surgery is a staged approach to the trauma patient in extremis that improves survival, but leads to open abdominal wounds that are difficult to manage. We evaluated whether directed peritoneal resuscitation (DPR) when used as a resuscitation strategy in severely injured trauma patients with hemorrhagic shock requiring damage control surgery would affect the amount of and timing of resuscitation and/or show benefits in time to abdominal closure and reduction of intra-abdominal complications.

STUDY DESIGN

A retrospective case-matched study of patients undergoing damage control surgery for hemorrhagic shock secondary to trauma between January 2005 and December 2008 was performed. Twenty patients undergoing standardized wound closure and adjunctive DPR were identified and matched to 40 controls by Injury Severity Score, age, gender, and mechanism of injury. A single early death was excluded because of inability to control ongoing hemorrhage.

RESULTS

There were no differences in age, gender, or mechanism of injury between the groups. Injury Severity Score (35.07 +/- 17.1 versus DPR 34.95 +/- 16.95; p = 0.82) and packed red blood cell administration in 24 hours (23.8 +/- 14.35 U versus DPR 26.9 +/- 14.1 U; p = 0.43) were similar between the groups. Presenting pH was similar between the study group and the DPR group (7.24 +/- 0.13 d versus DPR 7.26 +/- 0.11; p = 0.8). Time to definitive abdominal closure was significantly less in the DPR group compared with controls (DPR: 4.35 +/- 1.6 d versus 7.05 +/- 3.31; p < 0.003). DPR also allowed for a higher rate of primary fascial closure, lower intra-abdominal complication rate, and lower rate of ventral hernia formation at 6 months. Adjunctive DPR afforded a definitive wound closure advantage compared with Wittmann patch closure techniques (DPR 4.35 +/- 1.6 versus Wittmann patch 6.375 +/- 1.3; p = 0.004).

CONCLUSIONS

The addition of adjunctive DPR to the damage control strategy shortens the interval to definitive fascial closure without affecting overall resuscitation volumes. As a result, this mitigates intra-abdominal complications associated with open abdomen and damage control surgery and affords better patient outcomes.

Hemostatic properties of a venomic protein in rat organ trauma

Previous in vitro work characterized the protease Q8009 isolated from the venom of the Australian brown snake Pseudonaja textilis textilis with Factor Xa-like activity and hemostatic properties. The purpose of the work described here characterizes the in vivo hemostatic properties in a rat model of parenchymatous organ injury. The key parameters of activity included reduction in time-to-hemostasis and total volume of blood loss in spleen, liver and kidney wound models in rats. The surgical protocols involved exposure of the organs via a midline abdominal laparotomy. Using a clean metal template with 6, 6.5, 9 mm holes for spleen, liver and kidney, respectively, a predetermined volume of the organ was gently extruded through the template hole and excised with a razor blade. About 50 to 75 microL of collagen matrix with the different test solutions was applied to the wounds. Blood was collected and at the end of the procedure animals were humanely sacrificed with an anesthetic overdose. Determination of blood was performed using the hematin assay using a standard curve. Blood loss per minute and total blood loss were calculated. Results from the studies demonstrated that the application of Q8009 and collagen matrix to surgical wounds significantly reduced the total amount of blood loss and the time-to-hemostasis. In the spleen wound model, Q8009 at 100, 250 and 1000 microg/ml significantly reduced (p<0.001) the total volume of blood lost relative to thrombin and reduced the time-to-hemostasis by 25-50%, as compared to 7% by thrombin. In the liver wound model, Q8009 at 250 and 1000 microg/ml significantly reduced (p<0.001) the total volume of blood lost relative to thrombin and reduced the time-to-hemostasis from 10.5 min by thrombin to 5.6 min with Q8009. In the kidney wound model, Q8009 at 250 microg/ml significantly reduced (p<0.05) the total volume of blood lost and reduced the time-to-hemostasis by 25% when compared to thrombin. The hemostasis levels were consistent with previous findings in skin wound rat models where Q8009 consistently reduced the total volume of blood lost and shortened time-to-hemostasis. Application of Q8009 plus collagen matrix significantly reduced the volume of total blood loss and time-to-hemostasis in rat surgical organ wound models induced bleeding, as compared to a commercially available hemostat device. The protein Q8009 has greater capacity to reduce blood loss and shorten time-to-hemostasis; highly desirable properties where rapid hemostasis is needed in surgical wounds in parenchymatous organs.

Hemorrhage-induced hepatic injury and hypoperfusion can be prevented by direct peritoneal resuscitation

BACKGROUND

Crystalloid fluid resuscitation after hemorrhagic shock (HS) that restores/maintains central hemodynamics often culminates in multi-system organ failure and death due to persistent/progressive splanchnic hypoperfusion and end-organ damage. Adjunctive direct peritoneal resuscitation (DPR) using peritoneal dialysis solution reverses HS-induced splanchnic hypoperfusion and improves survival. We examined HS-mediated hepatic perfusion (galactose clearance), tissue injury (histopathology), and dysfunction (liver enzymes).

METHODS

Anesthetized rats were randomly assigned (n = 8/group): (1) sham (no HS); (2) HS (40% mean arterial pressure for 60 min) plus conventional i.v. fluid resuscitation (CR; shed blood + 2 volumes saline); (3) HS + CR + 30 mL intraperitoneal (IP) DPR; or (4) HS + CR + 30 mL IP saline. Hemodynamics and hepatic blood flow were measured for 2 h after CR completion. In duplicate animals, liver and splanchnic tissues were harvested for histopathology (blinded, graded), hepatocellular function (liver enzymes), and tissue edema (wet-dry ratio).

RESULTS

Group 2 decreased liver blood flow, caused liver injuries (focal to submassive necrosis, zones 2 and 3) and tissue edema, and elevated liver enzymes (alanine aminotransferase (ALT), 149 +/- 28 microg/mL and aspartate aminotransferase (AST), 234 +/- 24 microg/mL; p < 0.05) compared to group 1 (73 +/- 9 and 119 +/- 10 microg/mL, respectively). Minimal/no injuries were observed in group 3; enzymes were normalized (ALT 89 +/- 9 microg/mL and AST 150 +/- 17 microg/mL), and tissue edema was similar to sham.

CONCLUSIONS

CR from HS restored and maintained central hemodynamics but did not restore or maintain liver perfusion and was associated with significant hepatocellular injury and dysfunction. DPR added to conventional resuscitation (blood and crystalloid) restored and maintained liver perfusion, prevented hepatocellular injury and edema, and preserved liver function.

Postresuscitation tissue neutrophil infiltration is time-dependent and organ-specific

BACKGROUND

Hemorrhagic shock with conventional resuscitation (CR) primes circulating neutrophils and activates vascular endothelium for increased systemic inflammation, superoxide release, and end-organ damage. Adjunctive direct peritoneal resuscitation (DPR) with intraperitoneal instillation of a clinical peritoneal dialysis solution decreases systemic inflammation and edema formation by enhancing tissue perfusion. The aim of this study is to determine the effect of adjunctive DPR on neutrophil and fluid sequestration.

METHODS

Anesthetized rats were hemorrhaged to 40% mean arterial pressure for 60 min. Animals were randomized for CR with the return of the shed blood plus two volumes of saline, or CR plus adjunctive DPR with 30 mL of intraperitoneal injection of a clinical peritoneal dialysis solution. Tissue myeloperoxidase (MPO) level, a marker of neutrophil sequestration, and total water content were assessed in the gut, lung, and liver in sham animals and at time-points 1, 2, 4, and 24 h postresuscitation.

RESULTS

Resuscitation from hemorrhagic shock increases MPO level in all tissues in a near-linear fashion during the first 4 h following resuscitation. This occurs irrespective of the resuscitation regimen used. Tissue MPO level returned to baseline at 24 h following resuscitation except in the liver where CR and not adjunctive DPR caused a significant rebound increase. Adjunctive DPR prevented the CR-mediated obligatory fluid sequestration in the gut and lung and maintained a relative normal tissue water in these organs compared with CR alone (n = 7, F = 10.1, P < 0.01).

CONCLUSION

Hemorrhagic shock and resuscitation produces time-dependent organ-specific trends of neutrophil sequestration as measured with tissue levels of myeloperoxidase, a marker of neutrophil infiltration. Modulation of the splanchnic blood flow by direct peritoneal resuscitation did not alter the time-dependent neutrophil infiltration in end-organs, suggesting a subordinate role of blood rheology in the hemorrhage-induced neutrophil sequestration. Vulnerable window for neutrophil-mediated tissue damage exists during the first 4 h following resuscitation from hemorrhagic shock in rats. Direct peritoneal resuscitation prevents the early obligatory fluid sequestration and promotes early fluid mobilization.

Cellular edema regulates tissue capillary perfusion after hemorrhage resuscitation

BACKGROUND

Hemorrhage-induced activation of endothelial cell Na+/H+ -exchanger results in cellular swelling, which physically impedes capillary filling and compromises gut perfusion. We hypothesized that correction of the vascular volume deficit by conventional resuscitation does not improve capillary filling unless cellular swelling is prevented. Also, we hypothesized that adjunctive direct peritoneal resuscitation (DPR) with topical peritoneal dialysis solution (Delflex; Fresenius USA, Inc., Ogden, Ut) enhances capillary filling and gut perfusion by mechanisms that are independent of the Na+/H+ function.

METHODS

In vivo intravital videomicroscopy and Doppler velocimeter were used by us to measure microvascular diameter and flow, capillary filling (index of functional capillary density, FCD), and endothelial cell function in the terminal ileum of anesthetized rats. Rats were bled to 50% mean arterial pressure for 60 min and resuscitated with the shed blood plus 2 volumes of saline (conventional resuscitation). Prevention of endothelial cell swelling was achieved with topical amiloride (specific Na+/H+ inhibitor) in the tissue bath before hemorrhage or simultaneously with conventional resuscitation. DPR was simulated by instillation of Delflex in the tissue bath as adjunctive to conventional resuscitation. Sham no hemorrhage group and a simulated DPR group that received topical amiloride treatment served as controls.

RESULTS

Conventional resuscitation from hemorrhagic shock restored and maintained central hemodynamics but caused progressive and persistent intestinal vasoconstriction and hypoperfusion associated with low FCD and endothelial cell dysfunction. Prevention of endothelial cell swelling when combined with conventional resuscitation, preserved endothelial cell function, and restored local intestinal microvascular variables to near-prehemorrhage levels. Simulated adjunctive DPR produced rapid, sustained, and generalized vasodilation associated with restoration of endothelial cell function, and maximum recruitment of FCD independent of the Na+/H+ -exchanger function.

CONCLUSIONS

Paradoxical endothelial cell swelling occurs early during hemorrhagic shock because of activation of the Na+/H+ exchanger. This cellular edema, which is not resolved by correction of the vascular volume deficit, explains the persistent postresuscitation endothelial cell dysfunction and gut hypoperfusion. Simulated adjunctive DPR in this study reversed endothelial cell swelling and enhanced gut perfusion by mechanisms that are independent of the Na+/H+ exchanger activity.

Hemostatic properties of a venomic protein in rodent dermal injuries

Hemostatic properties of a factor Xa-like protease (Q8009) from the Australian snake Pseudonaja textilis textilis were determined. In tail-tip transection and dermal incision (hind limb) models, reagents were applied with collagen matrix. Blood was collected on filter paper chads for 12 one-minute intervals or until hemostasis. Determination of blood loss was performed using the hematin content and reported as blood loss per minute and total blood lost. Results from the studies demonstrated that the addition of the protease Q8009 and collagen matrix significantly reduced the volume of blood loss and shortened the time-to-hemostasis. In the dermal incision model, Q8009 (100, 250 and 1000 microg/ml) plus collagen matrix significantly reduced (p<0.001) the volume of blood lost relative to Thrombin and shortened the time-to-hemostasis to 2.0 min compared to 4.77 min with Thrombin. In the tail-tip transection model when Q8009 was mixed with a collagen matrix there was no significant reduction in blood loss, when compared to Thrombin plus collagen matrix. However, when injured tail-tips were held in Q8009 (1000 microg/ml) solution, there was a significant reduction (p<0.001) in blood loss (5.88 microl) versus that of Thrombin at 58.0 mul, and time-to-hemostasis was reduced from 11 min with Thrombin to 3 min when the Q8009 solution was used. In these studies, topical application of the venomic protease Q8009 significantly reduced total blood loss with a shorter time-to-hemostasis relative to Thrombin.

Mechanisms of direct peritoneal resuscitation-mediated splanchnic hyperperfusion following hemorrhagic shock

Conventional resuscitation (CR) from hemorrhagic shock causes a persistent and progressive splanchnic vasoconstriction and hypoperfusion despite hemodynamic restoration with intravenous fluid therapy. Adjunctive direct peritoneal resuscitation (DPR) with a clinical peritoneal dialysis solution instilled into the peritoneal cavity has been shown to restore splanchnic tissue perfusion, down-regulate the gut-derived exaggerated systemic inflammatory response, promote early fluid mobilization, and improve overall outcome. This study was conducted to define the molecular mechanisms of DPR-induced gut hyperperfusion after hemorrhagic shock. Male rats were bled to 50% baseline mean arterial pressure and resuscitated with the shed blood plus two volumes of saline (CR). In vivo videomicroscopy and Doppler velocimetry were used to assess terminal ileal microvascular diameters and blood flow. Direct peritoneal resuscitation animals received CR and topical application of a clinical glucose-based peritoneal dialysis solution (Delflex). Inhibitors, glibenclamide (K(+)ATP channels), N-monomethyl-L-arginine (L-NMMA) (nitric oxide synthase), 8-cyclopentyl-1,3-diprophylxanthine (DPCPX) (A1 adenosine receptor), tetrabutylammonium (K(+)Ca2+ channels), and mefenamic acid (cyclooxygenase) were topically applied (individually or in combination) with DPR according to protocol; BQ-123 (endothelin A receptor antagonist) and BQ-788 (endothelin B receptor antagonist) were used topically with CR to define the mechanism of post-CR vasoconstriction and hypoperfusion. Conventional resuscitation caused a persistent progressive intestinal vasoconstriction and hypoperfusion that can be abolished with endothelin antagonists. In contrast, adjunctive DPR caused an instantaneous sustained vasodilation and hyperperfusion. Glibenclamide or L-NMMA partially attenuated DPR-induced vasodilation, whereas the addition of DPCPX to the two inhibitors eliminated the dilation. Cyclooxygenase and K(+)Ca2+channels were not active in DPR-mediated microvascular effects. In conclusion, DPR improves splanchnic tissue perfusion by endothelium-dependent mechanisms mediated by activations of glibenclamide-sensitive K(+) channels (KATP), adenosine A1 receptor subtype activation, and nitric oxide release. Direct peritoneal resuscitation preserves endothelial dilatory functions, thereby overriding any endothelium-derived constrictor response triggered by hemorrhagic shock and CR.

Clinical peritoneal dialysis solutions modulate white blood cell-intestinal vascular endothelium interaction

BACKGROUND

Hemorrhagic shock (HS) with conventional resuscitation (CR) (HSCR) primes neutrophils and modulates leukocyte (WBC)-endothelium interaction as part of an exaggerated systemic inflammatory response. We hypothesize that topical application of clinical peritoneal dialysis solutions (PD) modulates such interaction.

METHODS

Intestinal intravital microscopy was used to measure WBC rolling in terminal ileum post capillary venules (V2 and V3) in sham-operated animals, and in animals that underwent fixed pressure hemorrhage (50% mean arterial pressure for 60 minutes), followed by conventional resuscitation with the return of the shed blood and 2 vol of saline. Number of rolling WBCs per thirty seconds in selected V2 and V3, bathed in either Kreb's solution or a 2.5% clinical peritoneal dialysis solution (PD) was quantified. Diameters were measured for the in-flow arterioles (A1), and out-flow venules (V1), for calculation of local blood flow with optical Doppler velocimetry.

RESULTS

The PD solution significantly (P < .05, n = 11) attenuated WBC-endothelium interaction in sham-operated animals while no significant difference was elicited in HSCR (P > .05, n = 9 Kreb's, n = 7 PD). In addition, the PD solution produced an instantaneous dilation at all levels of the intestinal arterioles in both sham and HSCR. While intestinal venular blood outflow was increased by the PD solution, venular diameters changed very little.

CONCLUSION

Superfusion of the gut with glucose-based peritoneal dialysis solutions decreases the concentration of rolling leukocytes along the venular vascular endothelium by a vasodilation-mediated increase in arteriolar inflow and venous outflow mechanism. Hemorrhagic shock and conventional resuscitation enhance the concentration of rolling leukocytes presumably by mechanisms related to upregulation of the adhesion molecules and the low-flow state. Hemorrhage and resuscitation-enhanced leukocytes rolling was not reversed by adjunctive DPR despite the associated marked increase in arterial inflow and venous outflow. The status of the endothelium and the level of leukocyte priming in low-flow states are stronger predictors of leukocyte-endothelium interaction than rheology factors.

Peritoneal resuscitation

BACKGROUND

After resuscitation from hemorrhagic shock, intestinal microvessels constrict leading to impaired mucosal blood flow. This occurs despite restoration of central hemodynamics. We review studies on the use of peritoneal dialysis fluid as an adjunct treatment in amelioration of this gut hypoperfusion.

METHODS

Using in vivo microscopy of the intestinal microcirculation, the effects of topically applied dextrose-based peritoneal dialysis fluid was measured. In other words, animal experiments, the survival benefits, the morbidity, blood flow distribution, and the postresuscitation inflammatory response to direct peritoneal resuscitation (DPR) were determined.

RESULTS

Simulated DPR caused a dramatic vasodilation compared with a progressive vasoconstriction when used during conventional resuscitation (CR) from hemorrhagic shock. It also reversed established vasoconstriction 2 and 4 hours after CR. In CR animals, there was a 40% mortality compared with 100% survival in DPR animals. DPR resulted in a downregulation of the gut-associated proinflammatory response noted after CR and similarly prevented edema formation.

CONCLUSION

DPR enhances organ blood flow to organs incited in the pathogenesis of multiple organ failure and improves survival after severe hemorrhage and CR.