Fluid resuscitation using the intraosseous route: infusion with lactated Ringer's and hetastarch.

OBJECTIVE: The effectiveness of the intraosseous (IO) route for fluid resuscitation remains uncertain. This study compares IO infusion rates and estimated volume expansion using clinically relevant infusion pressures with lactated Ringer's (LR) and hetastarch (HES). METHODS: IO needles were placed in the sternum or tibia for infusion of HES and LR in 8 Yorkshire pigs. Pressures were recorded at variable flow rates and linear regression used to identify flow rates at 100 and 400 mm Hg. Volume expansion was calculated for a 10-minute infusion. RESULTS: Mean LR flow rates (mL x min(-1)) were 24/111 (tibia--100/400 mm Hg) and 8/34 (sternum--100/400 mm Hg). The HES flow rates (mL x min(-1)) of 10/44 (tibia--100/400 mm Hg) and 6/26 (sternum--100/400 mm Hg) were significantly lower or -40% (p < 0.01) of the LR flow rates into the tibia and -70% (p < 0.05) into the sternum. Mean volume expansion (mL) for a 10-min infusion of LR was estimated to be 80/369 (tibia--100/400 mm Hg) and 27/112 (sternum--100/400 mm Hg). In comparison, HES volume expansion was -20% higher for the tibia (p > 0.05) and 110% to 120% higher for the sternum (p < 0.05). CONCLUSION: HES flow rates are lower than LR flow rates in the sternum and tibia of swine. Sternal infusion of HES is likely to provide greater estimated intravascular volume expansion than LR despite the lower infusion rates.

Anestesia em paciente obstétrica portadora de anemia falciforme e traço talassêmico após plasmaféresis: relato de caso / Anesthesia in obstetric patient with sickle cell anemia and thalassemic trait after plasmapheresis: case report

JUSTIFICATIVA E OBJETIVOS: A plasmaféresis é a técnica de tratamento de escolha para pacientes com anemia hemolítica grave. Uma de suas conseqüências é a depleção de colinesterase plasmática, o que interfere na metabolização de alguns bloqueadores neuromusculares de uso corrente na prática anestesiológica. RELATO DO CASO: Paciente com 26 anos, estado físico ASA IV, gestação de 30 semanas e 3 dias, portadora de anemia falciforme, traço talassêmico e alo-imunização para antígenos de alta freqüência. Apresentou crise de falcização, sendo transfundida com derivado sangüíneo incompatível. Evoluiu com hemólise maciça, sendo admitida com hemoglobina de 3 g/dL e hematócrito de 10 por cento, icterícia intensa, taquicardia, apatia e descoramento. Na avaliação hematológica concluiu-se ser situação de inexistência de sangue compatível para transfusão. Foi tratada com corticoterapia, imunoglobulinas e plasmaféresis. No segundo dia de internação, evoluiu com insuficiência renal aguda e edema pulmonar agudo, piora do estado geral e instabilidade hemodinâmica. Indicada a resolução da gestação em decorrência do quadro clínico da paciente e do sofrimento fetal agudo que se sobrepôs. A paciente foi admitida na sala de operações consciente, dispnéica, pálida, ictérica, SpO2 de 91 por cento em ar ambiente, freqüência cardíaca de 110 bpm e pressão arterial de 110 x 70 mmHg, em uso de dopamina (1 æg.kg-1.min-1) e dobutamina (10 æg.kg-1.min-1). Optou-se por anestesia geral balanceada, com alfentanil (2,5 mg), etomidato (14 mg) e atracúrio (35 mg) e isoflurano. Não se observou intercorrências anestésico-cirúrgicas. Ao final, a paciente foi encaminhada à UTI, sob intubação orotraqueal, e em uso de drogas vasoativas, tendo sido extubada após 3 horas. CONCLUSÕES: Este caso mostrou-se um desafio para a equipe, visto que a paciente apresentava instabilidade hemodinâmica e alteração do coagulograma, condições que contra-indicam a anestesia regional; além disto, a plasmaféresis potencialmente depleta os estoques de colinesterases plasmáticas, o que interfere na anestesia. Entretanto, o arsenal medicamentoso disponível permitiu o manuseio seguro desta situação.

[Anesthesia in obstetric patient with sickle cell anemia and thalassemic trait after plasmapheresis: case report]. / Anestesia em paciente obstétrica portadora de anemia falciforme e traço talassêmico após plasmaféresis: relato de caso.

BACKGROUND AND OBJECTIVES: Plasmapheresis is the technique of choice for severe hemolytic anemia patients. A consequence is plasma cholinesterase depletion, which interferes with metabolism of some neuromuscular blockers currently used in anesthesiology. CASE REPORT: Pregnant patient, 26 years old, physical status ASA IV, 30 weeks and 3 days gestational age, with sickle cell anemia, thalassemic trait and allo-immunization for high frequency antigens. Patient presented sickling crisis being transfused with incompatible blood. Patient evolved with massive hemolysis being admitted with 3 g/dL hemoglobin and 10% hematocrit, severe jaundice, tachycardia, apathic and pale. Hematological evaluation has concluded for the inexistence of compatible blood for transfusion. Patient was treated with steroids, immunoglobulins and plasmapheresis. In the second admission day patient evolved with acute renal failure and pulmonary edema, general state worsening and hemodynamic instability. Gestation resolution was indicated due to patient's clinical conditions and consequent acute fetal suffering. Patient was admitted to the operating room conscious, pale, with dyspnea, jaundice, 91% SpO2 in room air, heart rate of 110 bpm and blood pressure of 110 x 70 mmHg, under dopamine (1 microg.kg-1.min-1) and dobutamine (10 microg.kg-1.min-1). We decided for balanced general anesthesia with alfentanil (2.5 mg), etomidate (14 mg), atracurium (35 mg) and isoflurane. There were no anesthetic-surgical intercurrences. Patient was referred to ICU after surgery completion under tracheal intubation and vasoactive drugs, being extubated 3 hours later. CONCLUSIONS: This case was a challenge for the team since patient was hemodynamically instable with coagulogram abnormalities counterindicating regional anesthesia. In addition, plasmapheresis potentially depletes plasma cholinesterase reserves, interfering with anesthesia. However, available drug armamentarium has allowed for the safe management of this situation.