RESUMO
The goal of this study is to validate a new, continuous, noninvasive stroke volume (SV) method, known as transbrachial electrical bioimpedance velocimetry (TBEV). TBEV SV was compared to SV obtained by cardiac magnetic resonance imaging (cMRI) in normal humans devoid of clinically apparent heart disease. Thirty-two (32) volunteers were enrolled in the study. Each subject was evaluated by echocardiography to assure that no aortic or mitral valve disease was present. Subsequently, each subject underwent electrical interrogation of the brachial artery by means of a high frequency, low amplitude alternating current. A first TBEV SV estimate was obtained. Immediately after the initial TBEV study, subjects underwent cMRI, using steady-state precession imaging to obtain a volumetric estimate of SV. Following cMRI, the TBEV SV study was repeated. Comparing the cMRI-derived SV to that of TBEV, the two TBEV estimates were averaged and compared to the cMRI standard. CO was computed as the product of SV and heart rate. Statistical methods consisted of Bland-Altman and linear regression analysis. TBEV SV and CO estimates were obtained in 30 of the 32 subjects enrolled. Bland-Altman analysis of pre- and post-cMRI TBEV SV showed a mean bias of 2.87 % (2.05 mL), precision of 13.59% (11.99 mL) and 95% limits of agreement (LOA) of +29.51% (25.55 mL) and -23.77% (-21.45 mL). Regression analysis for pre- and post-cMRI TBEV SV values yielded y = 0.76x + 25.1 and r(2) = 0.71 (r = 0.84). Bland-Altman analysis comparing cMRI SV with averaged TBEV SV showed a mean bias of -1.56% (-1.53 mL), precision of 13.47% (12.84 mL), 95% LOA of +24.85% (+23.64 mL) and -27.97% (-26.7 mL) and percent error = 26.2 %. For correlation analysis, the regression equation was y = 0.82x + 19.1 and correlation coefficient r(2) = 0.61 (r = 0.78). Bland-Altman analysis of averaged pre- and post-cMRI TBEV CO versus cMRI CO yielded a mean bias of 5.01% (0.32 L min(-1)), precision of 12.85% (0.77 L min(-1)), 95% LOA of +30.20 % (+0.1.83 L min(-1)) and -20.7% (-1.19 L min(-1)) and percent error = 24.8%. Regression analysis yielded y = 0.92x + 0.78, correlation coefficient r(2) = 0.74 (r = 0.86). TBEV is a novel, noninvasive method, which provides satisfactory estimates of SV and CO in normal humans.
Assuntos
Artéria Braquial/fisiologia , Débito Cardíaco/fisiologia , Cardiografia de Impedância/métodos , Volume Sistólico/fisiologia , Adulto , Cardiografia de Impedância/instrumentação , Cardiografia de Impedância/estatística & dados numéricos , Desenho de Equipamento , Feminino , Humanos , Modelos Lineares , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Valores de Referência , Reologia/instrumentação , Reologia/métodos , Reologia/estatística & dados numéricosRESUMO
Activating clotting time (ACT) is a point-of-care, blood clotting test used to monitor anticoagulation. Recently, institutional requirements have required that ACT testing be completed outside the operating room with trained, certified personnel other than anesthesia staff. For this reason, in this study, we looked at whether a delay in processing an ACT makes a significant difference to the ACT results. Twenty patients between 18 and 65 years of age consented to the study, each undergoing non-cardiac surgery, with no intraoperative administration of heparin. The study was approved by our Institutional Review Board. A blood sample was taken from the patient's arterial line in the operating room. Immediately afterward, 1 mL was placed into each of two ACT cartridges and the measurement was done in a Medtronic ACT2 machine. The first ACT value was 126.9 +/- 14.5 seconds. The ACT value at approximately 30 minutes was 108.3 +/- 20.3 seconds (p < .0001). The time between the first and last measurements was 29.4 +/- 3.0 minutes. The results suggest that the ACT values decrease over time between sampling all measurements. At approximately 30 minutes, the ACT values average 15% less than the control measurements. Therefore, it would seem prudent to determine ACT values immediately in the operating room without any delay, using point-of-care testing.
Assuntos
Coagulação Sanguínea/fisiologia , Tempo de Coagulação do Sangue Total/instrumentação , Tempo de Coagulação do Sangue Total/métodos , Coagulação Sanguínea/efeitos dos fármacos , Desenho de Equipamento , Análise de Falha de Equipamento , Heparina/farmacologia , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fatores de TempoRESUMO
The potential advantages of regional anesthesia include minimal airway intervention, less cardiopulmonary depression, excellent postoperative analgesia, less postoperative nausea and vomiting, and shorter recovery room and hospital stays. These concerns are particularly important for the obese surgical patient. This review discusses the application of regional anesthetic techniques in obesity. Further clinical studies are needed to fill the knowledge gap about regional anesthesia and outcome in obese and morbidly obese patients.
Assuntos
Anestesia por Condução , Obesidade , Humanos , Obesidade/complicações , Obesidade/cirurgiaRESUMO
Preoperative assessment of blood volume (BV) is important for patients undergoing surgery. The mean value for indexed blood volume ((In)BV) in normal weight adults is 70 mL/kg. Since (In)BV decreases in a non-linear manner with increasing weight, this value cannot be used for obese and morbidly obese patients. We present an equation that allows estimation of (In)BV over the entire range of body weights.
Assuntos
Volume Sanguíneo , Obesidade Mórbida/fisiopatologia , Obesidade/fisiopatologia , Volume Sanguíneo/fisiologia , Índice de Massa Corporal , HumanosRESUMO
BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (RYGBP) is a commonly performed operation for morbid obesity. A significant number of patients experience postoperative nausea and vomiting (PONV) following this procedure. The aim of this study was to determine the effect, if any, of intra-operative fluid replacement on PONV. METHODS: Patients who underwent laparoscopic (RYGBP) for morbid obesity during a 12-month period were included in this retrospective analysis. Demographic data including age, gender, and body mass index (BMI) were collected. Perioperative data also included total volume of intra-operative fluids administered, rate of administration, urine output, length of surgery, and incidence of PONV as determined by nursing or anesthesia records in the postanesthesia care unit (PACU). Data were analyzed by t-test. RESULTS: The table below depicts demographic and perioperative data, comparing patients who experienced PONV (n=125) in the PACU with those who did not (n=55). Values are mean +/- standard deviation. CONCLUSIONS: PONV is a common complication after laparoscopic RYGB. Patient who did not experience PONV received a larger volume of intravenous fluid at a faster rate than similar patients who complained of PONV.
Assuntos
Derivação Gástrica/efeitos adversos , Náusea/epidemiologia , Vômito/epidemiologia , Adulto , Feminino , Humanos , Laparoscopia/efeitos adversos , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/fisiopatologia , Estudos RetrospectivosRESUMO
The appropriate dose of succinylcholine (SCH) in morbidly obese patients is unknown. We studied 45 morbidly obese (body mass index >40 kg/m2) adults scheduled for gastric bypass surgery. The response to ulnar nerve stimulation of the adductor pollicis muscle at the wrist was recorded using the TOF-Watch SX acceleromyograph. In a randomized double-blind fashion, patients were assigned to one of three study groups. In Group I, patients received SCH 1 mg/kg ideal body weight, in Group II 1 mg/kg lean body weight, and in Group III 1 mg/kg total body weight. After SCH administration, endotracheal intubating conditions were scored. The recovery from neuromuscular block was recorded for 20 min. There was no difference in the onset time of maximum neuromuscular blockade among groups, but maximum block was significantly less in Group I. The recovery intervals were significantly shorter in Groups I and II. In one third of the patients in Group I, intubating conditions were rated poor, whereas no patient in Group III had poor intubating conditions. Our study demonstrates that for complete neuromuscular paralysis and predictable laryngoscopy conditions, SCH 1 mg/kg total body weight is recommended.
Assuntos
Derivação Gástrica , Bloqueio Neuromuscular , Fármacos Neuromusculares Despolarizantes/administração & dosagem , Obesidade Mórbida , Succinilcolina/administração & dosagem , Adulto , Anestesia Geral , Índice de Massa Corporal , Peso Corporal , Método Duplo-Cego , Feminino , Humanos , Injeções Intravenosas , Intubação Intratraqueal , Masculino , Obesidade Mórbida/cirurgia , Transmissão SinápticaRESUMO
A simple formula for estimating ideal body weight (IBW) in kilograms for both men and women is presented. The equation IBW = 22 x H2, where H is equal to patient height in meters, yields weight values midway within the range of weights obtained using published IBW formulae.
Assuntos
Índice de Massa Corporal , Peso Corporal , Estatura , Feminino , Humanos , MasculinoRESUMO
STUDY OBJECTIVE: To assess intubating conditions without neuromuscular blocking drugs, to determine the relation between the dose of rocuronium and the probability of achieving excellent or at least good (good or excellent) intubating conditions with the intubating laryngeal mask airway (ILMA), and finally, to determine the relationship between rocuronium use and the success rate of endotracheal intubation. DESIGN: Prospective, randomized, double-blinded, placebo-controlled study. SETTING: University-affiliated medical center. PATIENTS: Sixty American Society of Anesthesiologists physical status I and II patients undergoing elective surgery. INTERVENTIONS: Anesthesia was induced with propofol 2.5 mg/kg and fentanyl 1 microg/kg. One minute after loss of consciousness, patients received rocuronium 0.2 mg/kg or saline. In the rocuronium group, if intubating conditions were scored as poor, rocuronium dose in the next patient was increased by 0.05 mg/kg. If intubating conditions were scored as good, no change was made, but if conditions were scored as excellent, the dose was decreased by 0.05 mg/kg. One minute after rocuronium or saline administration, an ILMA was used to intubate the trachea. If intubation was unsuccessful, a second attempt was made using the ILMA. MEASUREMENTS: We recorded intubating conditions and the success rate of tracheal intubation. MAIN RESULTS: Without rocuronium, the probability of achieving at least good intubating conditions with the ILMA was 30%. A rocuronium dose of 0.2 mg/kg resulted in a probability of 80% to achieve at least good intubating conditions. Rocuronium significantly increased the success rate of the second intubation attempt. CONCLUSION: To achieve good or excellent intubating conditions with the ILMA, a rocuronium dose lower than the standard intubating dose of 0.6 mg/kg can be used. Neuromuscular blockade increases the success rate of intubation if a second attempt is necessary.
Assuntos
Androstanóis/uso terapêutico , Intubação Intratraqueal/métodos , Máscaras Laríngeas , Fármacos Neuromusculares não Despolarizantes/uso terapêutico , Adulto , Método Duplo-Cego , Feminino , Humanos , Intubação/métodos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , RocurônioRESUMO
STUDY OBJECTIVE: To determine which patient parameters best predict left bronchial width (LBW) when selecting the correct size double-lumen tube (DLT). If LBW is known, a DLT that will fit that bronchus can be chosen. DESIGN: Prospective study. SETTING: University medical center. PATIENTS: Three hundred twenty-one consecutive patients scheduled for thoracic surgery and for whom there was a chest radiograph and for whom tracheal width (TW) and LBW could be measured. MEASUREMENTS: Tracheal width and LBW were directly measured from the chest radiograph. Patient demographic data were recorded and then analyzed to see which factor(s) best predicted LBW. Parameters often used for DLT selection (age, sex, height, and weight) as well as TW were compared by univariate and multivariate statistical analysis to see which factor(s) most accurately predicted LBW. MAIN RESULTS: There were weak but significant correlations between age and height and LBW in men, and height and LBW in women. Multivariate statistical analysis showed that, for both men and women, TW was the best predictor of LBW. Sex, height, and weight did not improve predictability over TW alone. The equation that best predicts LBW for both sexes is: LBWmm = (0.50)(TWmm) + 3.7 mm. This model explains 46% of the variance in LBW. As structures measured from a chest radiograph are magnified by 10%, the formula to predict LBW, which normalizes for this magnification factor, is: LBWmm = (0.45)(TWmm(CXR)) + 3.3 mm. CONCLUSIONS: Direct airway measurement is the most accurate way to select an appropriate DLT. However, when direct measurement of LBW cannot be performed, estimating LBW from TW is a better predictor of LBW than either sex, height, or weight.
Assuntos
Brônquios/anatomia & histologia , Intubação Intratraqueal/instrumentação , Traqueia/anatomia & histologia , Adulto , Idoso , Estatura , Peso Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores SexuaisRESUMO
BACKGROUND: The effect of patient position on the view obtained during laryngoscopy was investigated. METHODS: 60 morbidly obese patients undergoing elective bariatric were studied. Patients were randomly assigned into one of two groups. In Group 1, a conventional "sniff" position was obtained by placing a firm 7-cm cushion underneath the patient's head, thus raising the occiput a standard distance from the operating-table while the patient remained supine. In Group 2, a "ramped" position was achieved by arranging blankets underneath the patient's upper body and head until horizontal alignment was achieved between the external auditory meatus and the sternal notch. Following induction of general anesthesia, tracheal intubation was performed using a Video MacIntosh laryngoscope. The laryngoscopy and intubation sequences were recorded onto videotape. Three independent investigators, unaware as to which position the patient had been in at the time of tracheal intubation, then viewed the videotape and assigned a numerical grade to the best laryngeal view obtained. RESULTS: The "ramped" position improved the laryngeal view when compared to a standard "sniff" position, and this difference was statistically significant (P=0.037). CONCLUSION: The "ramped" position is superior to the standard "sniff" position for direct laryngoscopy in morbidly obese patients.
Assuntos
Intubação Intratraqueal/métodos , Laringoscopia/métodos , Obesidade Mórbida , Adulto , Comorbidade , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida/epidemiologia , Estudos ProspectivosRESUMO
STUDY OBJECTIVE: To determine the association between bispectral index (BIS) and seizure duration obtained by electroconvulsive therapy (ECT) administered sooner or later after anesthetic induction. DESIGN: Prospective, randomized, crossover study. SETTING: University-affiliated medical center. PATIENTS: Nine ASA physical status I, II, and III patients undergoing a total of 31 ECTs. INTERVENTIONS: ECT was administered soon (<210 sec) or later (between 210 sec and 360 sec) after anesthetic induction. In each individual patient, drug regimens and ECT machine settings were identical. MEASUREMENTS: BIS immediately before the start of the ECT and the duration of the EEG seizure were recorded, as well as the time period between loss of consciousness and ECT administration. MAIN RESULTS: There was no relationship between BIS level and seizure duration. Moreover, seizure duration was not dependent on the time of ECT administration in the time window between one and 6 minutes after loss of consciousness. CONCLUSION: The hypnotic drug effect measured by the BIS is not correlated to the seizure duration obtained by ECT.
Assuntos
Anestesia , Anestésicos , Eletroconvulsoterapia , Eletroencefalografia/efeitos dos fármacos , Idoso , Anestésicos Intravenosos , Estudos Cross-Over , Etomidato , Feminino , Humanos , Hipnóticos e Sedativos , Masculino , Metoexital , Pessoa de Meia-Idade , Estudos Prospectivos , Convulsões/fisiopatologia , TiopentalRESUMO
UNLABELLED: The objectives of this study were to test the effects of low-dose ketorolac and hydromorphone added to continuous local anesthetic wound instillation on surgical-site inflammatory mediators, postoperative pain, and opioid consumption. Sixty healthy women undergoing cesarean delivery were enrolled in this randomized, double-blinded study. Patients were randomized to receive a subcutaneous wound instillation of bupivacaine .5% at 10 mg/hour (active control), bupivacaine .5% with ketorolac .6 mg/hour, or bupivacaine .5% with hydromorphone .04 mg/hour for 48 hours postcesarean. Wound exudate was sampled at 4, 24, and 48 hours postcesarean and assayed for interleukins IL-1ß, IL-2, IL-6, IL-8, IL-10, and IL-12, tumor necrosis factor (TNF-α), interferon (INF-γ), and granulocyte-macrophage colony stimulating factor (GM-CSF). The addition of ketorolac to bupivacaine significantly decreased IL-6 (P = .012) and IL-10 (P = .005) compared to plain bupivacaine. Ketorolac, but not hydromorphone, was associated with a decrease in pain (P = .018) and analgesic use (P = .020) following cesarean delivery. Our results are compatible with the view that significant analgesics effects are mediated through local modulation of inflammatory events. Low-dose ketorolac administered into surgical wounds exert significant anti-inflammatory and analgesic effects and may be a valuable analgesic alternative to systemic nonsteroidal anti-inflammatories (NSAIDs) but with potentially fewer side effects. PERSPECTIVE: This article demonstrates that low-dose ketorolac administered into wounds modulates local inflammatory events, decreases postoperative pain, and reduces opioid consumption. These results suggest that administration of NSAIDs into surgical wounds may be an analgesic alternative to higher systemic dosing of NSAIDs.
Assuntos
Analgésicos Opioides/administração & dosagem , Analgésicos Opioides/uso terapêutico , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/uso terapêutico , Cesárea , Exsudatos e Transudatos/metabolismo , Hidromorfona/administração & dosagem , Hidromorfona/uso terapêutico , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Cetorolaco/administração & dosagem , Cetorolaco/uso terapêutico , Dor Pós-Operatória/prevenção & controle , Adulto , Anestésicos Locais/uso terapêutico , Bupivacaína/uso terapêutico , Citocinas/metabolismo , Método Duplo-Cego , Feminino , Humanos , Injeções Subcutâneas , Medição da Dor/efeitos dos fármacos , Cuidados Pós-Operatórios , GravidezAssuntos
Período de Recuperação da Anestesia , Anestesia Geral/métodos , Monitorização Intraoperatória/instrumentação , Obesidade Mórbida/cirurgia , Anestesia Geral/efeitos adversos , Segurança de Equipamentos , Feminino , Humanos , Masculino , Monitorização Intraoperatória/métodos , Obesidade Mórbida/diagnóstico , Cuidados Pré-Operatórios , Medição de Risco , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: This study was undertaken to compare the effect of deep hypothermic circulatory arrest, compared with moderate hypothermia, on the plasma concentrations and pharmacokinetic profile of vancomycin, administered as prophylaxis, in patients undergoing cardiac surgery with cardiopulmonary bypass. METHODS: Two groups of adult cardiac surgery patients were prospectively studied. One group consisted of 12 patients undergoing valvular surgery with moderate hypothermia, and another group was of 12 patients undergoing surgery with the use of profound hypothermic circulatory arrest. Vancomycin was administered before skin incision, and plasma levels were measured at regular intervals for 24h. RESULTS: The plasma concentrations of vancomycin showed a similar pattern in both groups. The pharmacokinetic profile showed a three-compartment model in both groups. CONCLUSION: The dosing of vancomycin, if used as antibiotic prophylaxis, does not need to be adjusted in cardiac surgery patients when undergoing profound hypothermic circulatory arrest, since the plasma concentrations and pharmacokinetic profile are similar to patients with moderate hypothermia. The pharmacokinetic profile, consisting of three compartments, was not changed by the differences in temperature.
Assuntos
Antibacterianos/sangue , Antibioticoprofilaxia/métodos , Procedimentos Cirúrgicos Cardíacos/métodos , Parada Circulatória Induzida por Hipotermia Profunda , Vancomicina/sangue , Adulto , Idoso , Ponte Cardiopulmonar , Feminino , Humanos , Hipotermia Induzida/métodos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Estudos Prospectivos , Infecção da Ferida Cirúrgica/sangue , Infecção da Ferida Cirúrgica/prevenção & controleRESUMO
BACKGROUND: Morbid obesity and bariatric surgery are both risk factors for the development of postoperative rhabdomyolysis (RML). RML results from injury to skeletal muscle, and a serum creatine phosphokinase (CK) level >1,000 IU/L is considered diagnostic of RML. The aim of this study was to determine if intraoperative intravenous fluid (IVF) volume affects postoperative CK levels following laparoscopic bariatric operations. STUDY DESIGN: Prospective, single blinded, and randomized trial was conducted. METHODS: Patients scheduled to undergo laparoscopic sleeve gastrectomy, adjustable gastric band, or Roux-en-Y gastric bypass operations were randomized into two groups. Subjects in Group A received 15 ml/kg total body weight (TBW) of IV crystalloid solution during surgery, while subjects in Group B received 40 ml/kg TBW. Preoperative and postoperative CK and creatinine levels and intra- and postoperative urine output were monitored and recorded. RESULTS: Forty-seven patients were assigned to Group A and 53 patients to Group B. Group B patients had significantly higher urine output in the operating room, in the post-anesthesia care unit (PACU), and on postoperative days 0 and 1. Group B patients also had significantly lower serum creatinine level in the PACU and a trend towards lower creatinine levels on postoperative days 0, 1, and 2. There were no statistical differences in CK levels at any time between the two groups. Four patients in Group A and three patients in Group B developed postoperative RML. CONCLUSIONS: Conservative (15 ml/kg) versus liberal (40 ml/kg) intraoperative IVF administration did not change the incidence of RML in patients undergoing laparoscopic bariatric operations. Since the occurrence of RML in this patient population is relatively high, postoperative CK levels should be routinely obtained in patients at special risk.
Assuntos
Creatina Quinase/sangue , Hidratação/métodos , Laparoscopia/métodos , Rabdomiólise , Adulto , Biomarcadores/sangue , Feminino , Gastrectomia/métodos , Derivação Gástrica/métodos , Gastroplastia/métodos , Humanos , Cuidados Intraoperatórios , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Rabdomiólise/enzimologia , Rabdomiólise/prevenção & controle , Fatores de Risco , Método Simples-Cego , UrinaAssuntos
Derivação Gástrica/métodos , Obesidade Mórbida/diagnóstico , Obesidade Mórbida/cirurgia , Índice de Massa Corporal , Peso Corporal , Feminino , Derivação Gástrica/efeitos adversos , Humanos , Masculino , Prognóstico , Medição de Risco , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
OBJECTIVES: We sought to assess the effects of cardiopulmonary bypass and profound hypothermic circulatory arrest on plasma cefazolin levels administered for antimicrobial prophylaxis in cardiovascular surgery. METHODS: Four groups (10 patients per group) were prospectively studied: vascular surgery without cardiopulmonary bypass (group A), cardiac surgery with a cardiopulmonary bypass time of less than 120 minutes (group B), cardiac surgery with a cardiopulmonary bypass time of greater than 120 minutes (group C), and cardiac surgery with cardiopulmonary bypass and profound hypothermic circulatory arrest (group D). Subjects received cefazolin at induction and a second dose before wound closure. Arterial blood samples were obtained preceding cefazolin administration, at skin incision, hourly during the operation, and before redosing. Cefazolin plasma concentrations were determined by using a radial diffusion assay, with Staphylococcus aureus as the indicator microorganism. Cefazolin plasma concentrations were considered noninhibitory at 8 microg/mL or less, intermediate at 16 mug/mL, and inhibitory at 32 microg/mL or greater. RESULTS: In group A cefazolin plasma concentrations remained greater than 16 microg/mL during the complete surgical procedure. In group B cefazolin plasma concentrations diminished to 16 microg/mL or less in 30% of the patients but remained greater than 8 microg/mL. In group C cefazolin plasma concentrations decreased to less than 16 microg/mL in 60% of patients and were less than 8 microg/mL in 50% of patients. In group D cefazolin plasma concentrations reached 16 microg/mL in 66% of the patients but decreased to 8 microg/mL in only 1 patient. CONCLUSIONS: For patients undergoing cardiac surgery with a cardiopulmonary bypass time of greater than 120 minutes, a single dose of cefazolin before skin incision with redosing at wound closure does not provide targeted antimicrobial cefazolin plasma levels during the entire surgical procedure. Patients undergoing profound hypothermic circulatory arrest are better protected, but the described protocol of prophylaxis is not optimal.