A Laparoscopically Compatible Rapid-Adhesion Bioadhesive for Asymmetric Adhesion, Non-Pressing Hemostasis, and Seamless Seal

Bioadhesive hydrogels offer unprecedented opportunities in hemostatic agents and tissue sealing; however, the application of existing bioadhesive hydrogels through narrow spaces to achieve strong adhesion in fluid-rich physiological environments is challenged either by undesired indiscriminate adhesion or weak wet tissue adhesion. Here, a laparoscopically compatible asymmetric adhesive hydrogel (aAH) composed of sprayable adhesive hydrogel powders and injectable anti-adhesive glue is proposed for hemostasis and to seal the bloody tissues in a non-pressing way, allowing for preventing postoperative adhesion. The powders can seed on the irregular bloody wound to rapidly absorb interfacial fluid, crosslink, and form an adhesive hydrogel to hemostatic seal (blood clotting time and tissue sealing in 10 s, ≈200 mm Hg of burst pressure in sealed porcine tissues). The aAH can be simply formed by crosslinking the upper powder with injectable glue to prevent postoperative adhesion (adhesive strength as low as 1 kPa). The aAH outperforms commercial hemostatic agents and sealants in the sealing of bleeding organs in live rats, demonstrating superior anti-adhesive efficiency. Further, the hemostatic seamless sealing by aAH succeeds in shortening the time of warm ischemia, decreasing the blood loss, and reducing the possibility of rebleeding in the porcine laparoscopic partial nephrectomy model.

Surgical Science and the Evolution of Critical Care Medicine

Surgical science has driven innovation and inquiry across adult and pediatric disciplines that provide critical care regardless of location. Surgically originated but broadly applicable knowledge has been globally shared within the pages Critical Care Medicine over the last 50 years.

Damage control strategy in bleeding trauma patients

Hemorrhagic shock is a main cause of death in severe trauma patients. Bleeding trauma patients have coagulopathy on admission, which may even be aggravated by incorrectly directed resuscitation. The damage control strategy is a very urgent and essential aspect of management considering the acute coagulopathy of trauma and the physiological status of bleeding trauma patients. This strategy has gained popularity over the past several years. Patients in extremis cannot withstand prolonged definitive surgical repair. Therefore, an abbreviated operation, referred to as damage control surgery (DCS), is needed. In addition to DCS, the likelihood of survival should be maximized for patients in extremis by providing appropriate critical care, including permissive hypotension, hemostatic resuscitation, minimization of crystalloid use, early use of tranexamic acid, and avoidance of hypothermia and hypocalcemia. This review presents an overview of the evolving strategy of damage control in bleeding trauma patients.

When Enough is Enough: Impact of Packed Red Blood Cells in Massive Transfusion Outcomes

Massive transfusion protocol (MTP) with fresh-frozen plasma and packed red blood cells (PRBCs) in a 1:1 ratio is one of the most common resuscitative strategies used in patients with severe hemorrhage. There are no studies to date that examine the best postoperative hematocrit range as a marker for survival after MTP. We hypothesize a postoperative hematocrit dose-dependent survival benefit in patients receiving MTP. This was a 53-month retrospective analysis of patients with intra-abdominal injuries requiring surgery and transfusion of 10 units PRBCs or more at a single Level I trauma center. Groups were defined by postoperative hematocrit (less than 21, 21 to 29, 29.1 to 39, and 39 or more). Kaplan-Meier (KM) survival probability was calculated. One hundred fifty patients requiring operative abdominal explorations and 10 units PRBCs or more were identified. There were no significant differences in demographics between groups. When comparing postoperative hematocrit groups, relative to a hematocrit of less than 21 per cent in KM survival analysis, an overall survival advantage was only evident in patients transfused to hematocrits 29.1 to 39 per cent ( P < 0.03; odds ratio [OR], 0.284; 95% confidence interval [CI], 0.089 to 0.914). This survival advantage was not seen in the other groups (21 to 29: OR, 0.352; 95% CI, 0.103 to 1.195 or 39% or greater: OR, 0.107; 95% CI, 0.010 to 1.121). This is the first study to examine the impact of postoperative hematocrit as an indicator of survival after MTP in the trauma patient. Transfusion to hematocrits between 29.1 and 39 per cent conveyed a survival benefit, whereas resuscitation to supraphysiologic hematocrits 39 per cent or greater conveyed no additional survival benefit. This study highlights the need for judicious PRBC administration during MTP and its potential impact on survival in patients with postoperative supraphysiologic hematocrits.

Planned re-laparotomy and the need for optimization of physiology and immunology

Planned re-laparotomy or damage control laparotomy (DCL), first described by Dr. Harlan Stone in 1983, has become a widely utilized technique in a broad range of patients and operative situations. Studies have validated the use of DCL by demonstrating decreased mortality and morbidity in trauma, general surgery and abdominal vascular catastrophes. Indications for planned re-laparotomy include severe physiologic derangements, coagulopathy, concern for bowel ischemia, and abdominal compartment syndrome. The immunology of DCL patients is not well described in humans, but promising animal studies suggest a benefit from the open abdomen (OA) and several human trials on this subject are currently underway. Optimal critical care of patients with OA's, including sedation, paralysis, nutrition, antimicrobial and fluid management strategies have been associated with improved closure rates and recovery.

Neurohormonal interactions on the renal oxygen delivery and consumption in haemorrhagic shock-induced acute kidney injury

Haemorrhagic shock is a common cause of acute kidney injury (AKI), which is a major risk factor for developing chronic kidney disease. The mechanism is superficially straightforward. An arterial pressure below the kidney's autoregulatory region leads to a direct reduction in filtration pressure and perfusion, which in turn cause renal failure with reduced glomerular filtration rate and AKI because of hypoxia. However, the kidney's situation is further worsened by the hormonal and neural reactions to reduced perfusion pressure. There are three major systems working to maintain arterial pressure in shock: sympathetic signalling, the renin-angiotensin system and vasopressin. These work to retain electrolytes and water and to increase peripheral resistance and cardiac output. In the kidney, the increased electrolyte reabsorption consumes oxygen. At the same time, at the signalling level seen in shock, all of these hormones reduce renal perfusion and thereby oxygen delivery. This creates an exaggerated hypoxic situation that is liable to worsen the AKI. The present review will examine this mechanistic background and identify a number of areas that require further studies. At this time, the ideal treatment of haemorrhagic shock appears to be slow fluid resuscitation, possibly with hyperosmolar sodium, low chloride and no artificial colloids. From the standpoint of the kidney, renin-angiotensin system inhibitors appear fruitful for further study.