Restoring microcirculatory perfusion in a preclinical model of severe hemorrhagic shock: The role of microcirculatory function.

BACKGROUND: No reflow in capillaries (no reflow) is the lack of tissue perfusion that occurs once central hemodynamics are restored. This prevents oxygen transfer and debt repayment to vital tissues after shock resuscitation. Since metabolic swelling of cells and tissues can cause no reflow, it is a target for study in shock. We hypothesize no reflow secondary to metabolic cell swelling causes the problem not addressed by current strategies that increase central hemodynamics alone. METHODS: Anesthetized swine were bled until plasma lactate reached 7.5 mM to 9 mM. Intravenous low volume resuscitation solutions were administered (6.8 mL/kg over 5 minutes) consisting of; (1) lactated Ringer (LR), (2) autologous whole blood, (3) high-dose vitamin C (200 mg/kg), or (4) 10% PEG-20k, a polymer-based cell impermeant that corrects metabolic cell swelling. Outcomes were macrohemodynamics (MAP), plasma lactate, capillary flow in the gut and tongue mucosa using orthogonal polarization spectral imaging (OPSI), and survival to 4 hours. RESULTS: All PEG-20k resuscitated swine survived 240 minutes with MAP above 60 mm Hg compared with 50% and 0% of the whole blood and LR groups, respectively. The vitamin C group died at just over 2 hours with MAPs below 40 and high lactate. The LR swine only survived 30 minutes and died with low MAP and high lactate. Capillary flow positively correlated ( p < 0.05) with survival and MAP. Sublingual OPSI correlated with intestinal OPSI and OPSI was validated with a histological technique. DISCUSSION: Targeting micro-hemodynamics in resuscitation may be more important than macrohemodynamics. Fixing both is optimal. Sublingual OPSI is clinically achievable to assess micro-hemodynamic status. Targeting tissue cell swelling that occurs during ATP depletion in shock using optimized osmotically active cell impermeants in crystalloid low volume resuscitation solutions improves perfusion in shocked tissues, which leverages a primary mechanism of injury.

Blood and fluid management during scoliosis surgery: a single-center retrospective analysis.

AIM: In the present retrospective study in scoliosis surgery, we hypothesized that application of a protocol for blood and fluid management, based on goal-directed fluid therapy, cell salvage and tranexamic acid, could lead to reduced allogeneic red blood cells transfusion. METHODS AND MATERIAL: Thirty-five patients, with American Society of Anesthesiologists physical status I/III, between 14 and 18 years scheduled for elective orthopedic surgery of scoliosis, with a planned intensive care unit admission, were enrolled in a retrospective observational study. Patients were divided in two groups. Patients in no-protocol group (Group noPro, n = 18) received a liberal intraoperative fluid therapy and patients in protocol group (Group Pro, n = 17) received fluid therapy managed according to a stroke volume variation-based protocol. The protocol included fluid therapy according to SVV monitor, permissive hypotension, tranexamic acid infusion, restrictive RBC trigger and use of perioperative cell savage. STATISTICAL ANALYSIS USED: Student's t test (2-tailed), Mann-Whitney test, Chi square test were used for statistical analysis of the data. RESULTS: There were no significant differences between the two groups in demographic data and clinical characteristics. Infused crystalloids (p = .003) and transfused allogeneic red blood cells (p = .015) were lesser in Group Pro compared to Group noPro. On the other hand, diuresis (p < .001) and vasopressors administration (p = .042) were higher in Group Pro than in Group noPro. CONCLUSION: The application of a protocol for blood and fluid management, based on goal-directed fluid therapy, cell salvage and tranexamic acid, was associated with less crystalloid fluid administration, less perioperative RBC transfusions and significantly better diuresis than patients in the no-protocol group in scoliosis surgery. REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT03814239.

The effects of crystalloid warming on maternal body temperature and fetal outcomes: a randomized controlled trial / Os efeitos do aquecimento de cristaloides sobre a temperatura corporal materna e nas condições fetais: ensaio clínico randômico

Abstract Background and objectives: Hypothermia occurs in about 60% of patients under anesthesia and is generally not managed properly during short lasting surgical procedures. Hypothermia is associated with adverse clinical outcomes. The current study is designed to assess the effects of crystalloid warming on maternal and fetal outcomes in patients undergoing elective cesarean section with spinal anesthesia. Methods: In this prospective randomized controlled trial, sixty parturients scheduled for elective cesarean section with spinal anesthesia were randomly allocated to receive crystalloid at room temperature or warmed at 37 °C. Spinal anesthesia was performed at L3-L4 interspace with 10 mg of hyperbaric bupivacaine without adding opioids. Core temperature, shivering, and hemodynamic parameters were measured every minute until 10th minute and 5-min intervals until the end of operation. The primary outcome was maternal core temperature at the end of cesarean section. Results: There was no difference for baseline tympanic temperature measurements but the difference was significant at the end of the operation (p = 0.004). Core temperature was 36.8 ± 0.5 °C at baseline and decreased to 36.3 ± 0.5 °C for isothermic warmed crystalloid group and baseline tympanic core temperature was 36.9 ± 0.4 °C and decreased to 35.8 ± 0.7 °C for room temperature group at the end of the operation. Shivering was observed in 43.3% in the control group. Hemodynamic parameter changes and demographic data were not significant between groups. Conclusions: Isothermic warming crystalloid prevents the decrease in core temperature during cesarean section with spinal anesthesia in full-term parturients. Fetal Apgar scores at first and fifth minute are higher with isothermic warming.

Resumo Justificativa e objetivos: A hipotermia ocorre em cerca de 60% dos pacientes sob anestesia e geralmente não é tratada adequadamente durante procedimentos cirúrgicos de curta duração. A hipotermia está associada a desfechos clínicos adversos. O presente estudo teve como objetivo avaliar os efeitos do aquecimento de cristaloides nas condições maternas e fetais em pacientes submetidas à cesariana eletiva com raquianestesia. Métodos: Neste estudo prospectivo, randômico e controlado, 60 parturientes agendadas para cesárea eletiva com raquianestesia foram distribuídas aleatoriamente para receber cristaloides à temperatura ambiente ou aquecidos a 37 °C. A raquianestesia foi realizada no interespaço L3-L4 com 10 mg de bupivacaína hiperbárica sem adição de opioides. Temperatura central, tremores e parâmetros hemodinâmicos foram medidos a cada minuto até o décimo minuto e em intervalos de 5 min até o fim da operação. O desfecho primário foi a temperatura central materna ao final da cesárea. Resultados: Não houve diferença nas mensurações basais da temperatura timpânica, mas a diferença foi significativa no fim da operação (p = 0,004). A temperatura central foi de 36,8 ± 0,5 °C na fase basal e diminuiu para 36,3 ± 0,5 °C no grupo com aquecimento isotérmico de cristaloides e a temperatura basal timpânica foi de 36,9 ± 0,4 °C e diminuiu para 35,8 ± 0,7 °C no grupo sem aquecimento das soluções no fim da operação. Tremores foram observados em 43,3% no grupo controle. Alterações nos parâmetros hemodinâmicos e dados demográficos não foram significantes entre os grupos. Conclusões: O aquecimento isotérmico de cristaloides previne a redução da temperatura central durante a cesariana com raquianestesia em parturientes a termo. Os escores de Apgar para os fetos no primeiro e quinto minutos são maiores com o aquecimento isotérmico.

[The effects of crystalloid warming on maternal body temperature and fetal outcomes: a randomized controlled trial]. / Os efeitos do aquecimento de cristaloides sobre a temperatura corporal materna e nas condições fetais: ensaio clínico randômico.

BACKGROUND AND OBJECTIVES: Hypothermia occurs in about 60% of patients under anesthesia and is generally not managed properly during short lasting surgical procedures. Hypothermia is associated with adverse clinical outcomes. The current study is designed to assess the effects of crystalloid warming on maternal and fetal outcomes in patients undergoing elective cesarean section with spinal anesthesia. METHODS: In this prospective randomized controlled trial, sixty parturients scheduled for elective cesarean section with spinal anesthesia were randomly allocated to receive crystalloid at room temperature or warmed at 37°C. Spinal anesthesia was performed at L3-L4 interspace with 10mg of hyperbaric bupivacaine without adding opioids. Core temperature, shivering, and hemodynamic parameters were measured every minute until 10th minute and 5-min intervals until the end of operation. The primary outcome was maternal core temperature at the end of cesarean section. RESULTS: There was no difference for baseline tympanic temperature measurements but the difference was significant at the end of the operation (p=0.004). Core temperature was 36.8±0.5°C at baseline and decreased to 36.3±0.5°C for isothermic warmed crystalloid group and baseline tympanic core temperature was 36.9±0.4°C and decreased to 35.8±0.7°C for room temperature group at the end of the operation. Shivering was observed in 43.3% in the control group. Hemodynamic parameter changes and demographic data were not significant between groups. CONCLUSIONS: Isothermic warming crystalloid prevents the decrease in core temperature during cesarean section with spinal anesthesia in full-term parturients. Fetal Apgar scores at first and fifth minute are higher with isothermic warming.