Monitoring modalities and assessment of fluid status: A practice management guideline from the Eastern Association for the Surgery of Trauma.

BACKGROUND: Fluid administration in critically ill surgical patients must be closely monitored to avoid complications. Resuscitation guided by invasive methods are not consistently associated with improved outcomes. As such, there has been increased use of focused ultrasound and Arterial Pulse Waveform Analysis (APWA) to monitor and aid resuscitation. An assessment of these methods using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework is presented. METHODS: A subsection of the Surgical Critical Care Task Force of the Practice Management Guideline Committee of EAST conducted two systematic reviews to address the use of focused ultrasound and APWA in surgical patients being evaluated for shock. Six population, intervention, comparator, and outcome (PICO) questions were generated. Critical outcomes were prediction of fluid responsiveness, reductions in organ failures or complications and mortality. Forest plots were generated for summary data and GRADE methodology was used to assess for quality of the evidence. Reviews are registered in PROSPERO, the International Prospective Register of Systematic Reviews (42015032402 and 42015032530). RESULTS: Twelve focused ultrasound studies and 20 APWA investigations met inclusion criteria. The appropriateness of focused ultrasound or APWA-based protocols to predict fluid responsiveness varied widely by study groups. Results were mixed in the one focused ultrasound study and 9 APWA studies addressing reductions in organ failures or complications. There was no mortality advantage of either modality versus standard care. Quality of the evidence was considered very low to low across all PICO questions. CONCLUSION: Focused ultrasound and APWA compare favorably to standard methods of evaluation but only in specific clinical settings. Therefore, conditional recommendations are made for the use of these modalities in surgical patients being evaluated for shock. LEVEL OF EVIDENCE: Systematic Review, level II.

Advances in resuscitation strategies.

Shock, regardless of etiology is characterized by decreased delivery of oxygen and nutrients to the tissues and our interventions are directed towards reversing the cellular ischemia and preventing its consequences. The treatment strategies that are most effective in achieving this goal obviously depend upon the different types of shock (hemorrhagic, septic, neurogenic and cardiogenic). This brief review focuses on the two leading etiologies of shock in the surgical patients: bleeding and sepsis, and addresses a number of new developments that have profoundly altered the treatment paradigms. The emphasis here is on new research that has dramatically altered our treatment strategies rather than the basic pathophysiology of shock.

Intraoperative evaluation of tissue perfusion in high-risk patients by invasive and noninvasive hemodynamic monitoring.

OBJECTIVE: Although invasive monitoring has not been effective in late stages after organ failure has occurred, early postoperative monitoring revealed differences in survivor and nonsurvivor patterns and provided goals for improving outcome. We searched for the earliest divergence of survivor and nonsurvivor circulatory changes as an approach to earlier preventive therapy. The aim was to describe the intraoperative time course of circulatory dysfunction in survivors and nonsurvivors among high-risk elective surgery patients using both the thermodilution pulmonary artery catheter (PAC) and multicomponent noninvasive monitoring. DESIGN: Prospective intraoperative description of circulatory dysfunction. SETTING: University-run county hospital. PATIENTS: Two hundred nine consecutively monitored high-risk elective surgery patients. MEASUREMENTS AND MAIN RESULTS: We evaluated the data of high-risk elective surgery patients using both PAC and multicomponent noninvasive monitoring. The latter consisted of the following: a) an improved bioimpedance method for estimating cardiac output; b) the standard pulse oximetry to screen for pulmonary problems; c) transcutaneous oxygen and carbon dioxide tension sensors to evaluate tissue perfusion; and d) routine noninvasive blood pressure and heart rate. The current noninvasive impedance cardiac output estimations closely approximated those of the thermodilution method; r2 = .74, p < .001; the precision and bias was -0.124 +/- 0.75 L/min/m2. Outcome measures included intraoperative description of circulatory patterns of high-risk surgical patients who survived compared with nonsurvivors. Hypotension, low cardiac index, arterial hemoglobin desaturation, low transcutaneous oxygen, high transcutaneous carbon dioxide tensions, low oxygen delivery, and low oxygen consumption developed intraoperatively gradually over time; the abnormalities were more pronounced in the nonsurvivors than in the survivors. CONCLUSIONS: The survivors had slightly higher mean arterial pressure, cardiac index, and mixed venous oxygen saturation, as well as significantly higher oxygen delivery, oxygen consumption, transcutaneous oxygen tension, and transcutaneous oxygen tension/FIO2 ratios, than did the nonsurvivors. The data suggest that blood flow, oxygen delivery, and tissue oxygenation of the nonsurvivors became inadequate toward the end of the operation. Noninvasive monitoring provides similar information to that of the PAC; both approaches revealed low-flow and poor tissue perfusion that were worse in the nonsurvivors. The continuous on-line real-time displays of hemodynamic trends facilitate early recognition of acute circulatory dysfunction.

Hemodynamic patterns of survivors and nonsurvivors during high risk elective surgical operations.

Postoperative survivors' and nonsurvivors' hemodynamic and oxygen transport patterns have been extensively studied, and the early postoperative circulatory events leading to organ failures and death have been documented. Outcome was improved when potentially lethal circulatory patterns were treated during the early (the first 8-12 hours) postoperative period; but after the appearance of organ failure, reversal of nonsurvival patterns did not improve the outcome. The purpose of this study was to describe prospectively intraoperative circulatory deficiencies that precede shock, organ failures, and death. The ultimate aim was to elucidate nonsurvivor patterns at the earliest possible time to develop more effective preventive strategies for lethal organ failures. This approach is based on the assumption that it is easier and more effective to prevent the initiators of shock, such as hypovolemia, hypoxemia, poor tissue perfusion, and tissue hypoxia, than to treat the mediators of organ failure, such as cytokines, antigens, eicosinoids, and heat shock proteins. We monitored 356 high risk elective surgical patients with preoperative and intraoperative hemodynamic monitoring by the pulmonary artery (PA) thermodilution catheter. The conventionally monitored mean arterial pressure and heart rate remained in the normal range in both groups; the nonsurvivor pattern included decreased cardiac index, stroke index, stroke work, oxygen delivery, and oxygen consumption. Low oxygen consumption was partly compensated by increased oxygen extraction rates, and arterial pressures were maintained by increasing systemic vascular resistance. The early temporal pattern of nonsurvivors' changes were similar to those described during the postoperative period that preceded development of organ failure and death. This suggests that lethal circulatory dysfunctions may begin during the intraoperative period but become more apparent before and after organs fail during later postoperative stages.

Acute adrenal insufficiency presenting as shock after trauma and surgery: three cases and review of the literature.

Profound nonhemorrhagic shock developed in one postoperative and two trauma patients. Cardiovascular collapse was characterized by severe hypotension (systolic blood pressure less than 80 mm Hg), hyperdynamic cardiac indices (CI greater than 4 L/min/m2), low systemic vascular resistance (SVR less than 500 dyne.sec/cm5.m2), and multiple organ failure. Sepsis was not found by culturing of specimens or visual inspection at laparotomy. Screening cortisol levels were low (less than 2 micrograms/dL in two patients) and did not respond appropriately to synthetic ACTH (cosyntropin) challenge. Administration of exogenous glucocorticoids promptly and dramatically reversed shock and organ failure in two patients. Oral glucocorticoid and mineralocorticoid supplementation were required at hospital discharge. Acute adrenal insufficiency is rare after trauma, but may produce life-threatening cardiovascular collapse, mimicking the "septic" shock state. Cosyntropin stimulation testing confirms the diagnosis and is accurate in traumatized patients. Outcome is dependent upon early recognition and exogenous glucocorticoid administration. Appropriate endocrine evaluation prevents unnecessary use of steroids in a population of trauma patients who are already in a state of immunosuppression.

Continuous monitoring of pH in the tissue mode: evaluation of a miniature sensor during acidosis and tissue hypoperfusion.

The in vivo performance of a 20G copolymer pH sensor, needlelike in configuration, was studied in the normal dog, and dogs made acidotic by the constant infusion of lactic acid, or by the induction of tissue perfusion defects. Sensors were placed at two extravascular sites in the leg, deep subcutaneous (pHe/sc), and intramuscular in the adductor (pHe/im). This pH sensor is a silver wire capped by a H+-specific polymer; it has a built-in reference system. Its electrochemical characteristics and in vivo performance are similar to those of glass pH electrodes. The continuously monitored values were compared with discrete arterial blood gas analyses at 10 to 20 minute intervals. The baseline values in 15 dogs under general anesthesia were: pH/art 7.331 +/- .042, pHe/sc 7.291 +/- .076, and pHe/im 7.265 +/- .102 (mean +/- SD; n = 45 observations each). During metabolic acidosis (lactic acid infusion), the direction and rates of change were similar in pHe/sc and pHe/im. Tissue perfusion defects were induced by moderate-to-severe hemorrhage (single or repeated bleeds) or operative shock (splenectomy and exteriorization of bowel). Both pHe/sc and pHe/im fell sharply, with a more gradual drop in pH/art. In those who survived after infusion of shed blood or dextran-40, pHe recovered rapidly. In the moribund, pHe continued to deteriorate. This pH sensor is a sensitive prognosticator of acid-base changes in the tissue. The in vivo drift is small: 0.008 pH per hour. The placement of the sensor via an intracath cannula in the subcutaneous tissue of the thigh is recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

[Collapse and functional adrenocortical failure in surgical interventions]. / Kollaps i funktsional'naia nedostatochnost' kory nadpochechnikov pri khirurgicheskikh vmeshatel'stvakh.

The authors observed collapses during operations under narcosis resulting from the adrenal insufficiency in 0,75% of the operated patients. Patients with the potential adrenal insufficiency were detected by means of laboratory and clinical investigations. In order to prevent its development before, during and after the operation a substituting therapy with hydrocortisone was carried out.

[Renal perfusion during experimental hyper-acute rejection. 133-xenon perfusion compared with microscopy and angiography (author's transl)]. / Nierenperfusion bei hyperakuter xenogener abstrssung im Tierversuch. 133-Xenon-Durchblutung im Vergleich zur Mikroskopie und Angiographie.

Twenty-two cat kidneys and 11 pig kidneys were incorporated into canine circulatory systems. The delayed hyper-acute and hyper-acute rejections produced by these models were studied with respect to blood flow and blood distribution with an intra-arterial 133-xenon wash-out technique at intervals of 7-30 minutes until the death of the kidney at 40 minutes to twelve hours. In addition, magnification angiograms and serial cortical biopsies were obtained for continuous histological study of the rejection phenomenon. At the beginning of the rejection process, there is a reduction in blood-flow through the cortex. During delayed hyper-acute rejection, cortical flow could no longer be demonstrated 180 minutes after the period of flow maximum. After A.L.G. treatment of dogs, rejection could be delayed for ten to twelve hours. Magnification angiograms showed characteristic changes consisting of irregular segmental and interlobar arteries, occlusion of small cortical vessels and focal contrast accumulation in the renal cortex. The changes in blood-flow and blood distribution measured with 133-xenon and the vascular findings on the angiogram could be correlated with the microscopic findings. Serial estimations of blood flow and blood distribution with the xenon blood wash-out technique permit differentiation between shock kidney and rejection following renal transplantation.