RESUMO
A minitracheostomy (MTS) is performed after surgery for oral cancer at our institution in patients who are at risk of postoperative airway obstruction. The aim of this study was to evaluate outcomes of preventive airway management with this procedure. A total of 105 patients undergoing preventive airway management with a Seldinger MTS kit after oral cancer surgery between October 2014 and March 2020 were enrolled. Information on patient characteristics, time required for the MTS, duration of tracheal cannula placement, and MTS-related complications was obtained from both the medical and anesthesia records. In addition, the numbers of postoperative instances of tracheotomy between April 2009 and September 2014 and extubation between October 2014 and March 2020 were also counted for a comparison. The time required for an MTS was 3.2±2.6 min. Minor complications, including mild subcutaneous or mediastinal emphysema and bleeding, were found in 5 patients, but all recovered in a short time. The median duration of tracheal cannula placement was 2 days, with a range of from 0 to 8 days. A total of 348 oral cancer surgeries were performed between April 2009 and September 2014. Among patients undergoing these procedures, 111 underwent a tracheostomy (32%), 235 extubation (68%), and 2 sustained intubation. A total of 580 oral cancer surgeries were performed between October 2014 and March 2020. Here, 121 patients underwent a tracheostomy (21%), 105 an MTS (18%), and 354 extubation (61%). The results suggest that an MTS can be performed safely and smoothly with no significant complications. They also suggest that an MTS reduces the need for a full tracheostomy and the risk of airway obstruction after extubation. We conclude that airway management strategy with an MTS is a useful option in preventing airway obstruction following oral cancer surgery.
Assuntos
Obstrução das Vias Respiratórias , Neoplasias Bucais , Manuseio das Vias Aéreas , Obstrução das Vias Respiratórias/etiologia , Obstrução das Vias Respiratórias/prevenção & controle , Humanos , Intubação Intratraqueal/efeitos adversos , Neoplasias Bucais/cirurgia , Estudos RetrospectivosRESUMO
PURPOSE: Tapentadol is a dual-acting mu-opioid receptor agonist and noradrenaline reuptake inhibitor with non-inferior analgesic efficacy to oxycodone and better gastrointestinal tolerability than full mu-opioid receptor agonists. Tapentadol is approved for cancer pain in Japan; however, real-world evidence on tapentadol's effectiveness and safety for cancer-related pain in Japan is limited. METHODS: This retrospective study evaluated the effectiveness, safety, and tolerability of tapentadol (by patient type-opioid-naïve and opioid-tolerant) in 84 patients with moderate-to-severe cancer pain at Ichikawa General Hospital between September 2014 and August 2016. RESULTS: Almost 93% of patients achieved clinically relevant pain relief within 4 days (median). Over 90% of patients with neuropathic pain or mixed pain and all patients with nociceptive pain were responders. Pain intensity significantly decreased from baseline through to the end of maintenance period in opioid-naïve and opioid-tolerant patients. No patients discontinued tapentadol due to serious adverse events. No opioid-naïve patients experienced nausea or vomiting during tapentadol treatment. Only three opioid-tolerant patients experienced nausea which was considered to be related to tapentadol. CONCLUSION: Tapentadol is effective and well tolerated in opioid-naïve and opioid-tolerant patients with cancer pain of varying pathophysiology, including those with nociceptive and/or neuropathic components. Tapentadol may be considered for first-line use in moderate-to-severe cancer-related pain.
Assuntos
Dor do Câncer , Neoplasias , Idoso , Analgésicos Opioides/uso terapêutico , Dor do Câncer/tratamento farmacológico , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Neoplasias/complicações , Fenóis/uso terapêutico , Estudos Retrospectivos , TapentadolRESUMO
Since 2018, we have been using a 3D printer to fabricate a proprietary device for fixing nasotracheal tubes. The aim of this retrospective study was to investigate the impact of this nasotracheal intubation (NTI) fixation device. It has been used in 335 patients undergoing general anesthesia for oral and maxillofacial surgeries. No necrosis or permanent tissue damage was observed, and none of the patients developed complications requiring treatment. No unintentional tube-related incidents such as extubation, dislocation of the tube, or disconnection between the tube and the artificial respiration circuit occurred either. This fixation device offers three advantages: safety, no impediment to surgery, and minimal invasiveness. Of these, safety is the most important. The high degree of immobilization it offers makes it possible to prevent injury to the nasal ala when the tracheal tube is tugged to the cranial side. There is also a high degree of immobilization at the connection site between the tracheal tube and anesthesia circuit, making it possible to prevent disconnection due to intraoperative pressure. In addition, safety during fixation is less likely to differ depending on the degree of proficiency of the individual anesthesiologist. The presence of a groove through which the sampling tube of the capnometer can be passed makes it possible to prevent the problem of flexion of the sampling tube, rendering detection impossible during surgery. Thus, use of this fixation device offers the potential to improve immobilization of the tracheal tube and increase intraoperative safety. However, there remain several problems that need to be addressed with this novel device. Further improvements aimed at enhancing safety are planned, therefore.
Assuntos
Cavidade Nasal , Cirurgia Bucal , Anestesia Geral , Humanos , Intubação Intratraqueal/efeitos adversos , Estudos RetrospectivosRESUMO
A 41-year-old woman with anti-N-methyl-D-aspartate (NMDA) receptor encephalitis, characterized by vari- ous psychiatric disturbances, was scheduled for laparo- scopic salpingo-oophorectomy. Anesthesia was induced with fentanyl, propofol and rocuronium, and maintained with intravenous propofol combined with epidural anesthesia (T10-11). The patient received 20 mEq of MgSO4 after induction. MgSO4 administrations were repeated at the end of surgery and every 12 hours for 48 hours after the operation. The operation was per- formed successfully, without any troubles. Trachea was extubated in the operating room. The cognitive dys- function was not observed postoperatively. There was no complication and no unexpected event postopera- tively. One month after surgery, the patient's clinical symptom began to improve. The resection of tumor is recommended as a thera- peutic treatment ; however, there has been few report of the management of postoperative cognitive dysfunc- tion for patients with NMDA receptor antibodies. These patients were more likely to experience a post- operative cognitive dysfunction associated with a poor outcome. We, therefore, administered magnesium sul- fate, NMDA antagonist to prevent postoperative delir- ium. In the present case, magnesium sulfate might have prevented the incidence of postoperative delirium without any complications. The prophylactic magne- sium administration could prevent postoperative delir- ium and agitation safely.
Assuntos
Encefalite Antirreceptor de N-Metil-D-Aspartato , Delírio , Adulto , Extubação , Anestesia Epidural , Autoanticorpos/imunologia , Cognição , Feminino , Humanos , Período Pós-OperatórioRESUMO
Governmental policies recommend the palliative care at home for cancer patients. However, there are some barriers to discharge cancer patients from the hospital who want to receive end-of-life care at their homes. Anesthesiologists whose main job is to perform general anesthesia in the operating theater usually have little contact with general practitioners giving community palliative care. So it is important to communicate each other to make opportunities to discuss an organized system and care plan for these patients, and to improve information transfer.
Assuntos
Anestesia , Serviços de Assistência Domiciliar , Cuidados Paliativos , Papel do Médico , Anestesia/métodos , Humanos , Neoplasias/complicações , Alta do Paciente , Assistência TerminalRESUMO
BACKGROUND: Postoperative analgesia is important in patients undergoing open abdominal surgery. We prospectively compared the efficacy of ropivacaine and that of levobupivacaine for postoperative epidural analgesia in patients undergoing gynecological open abdominal surgery. METHODS: Fifty-two ASA 1-2 patients scheduled for gynecological open abdominal surgery under combined general and epidural anesthesia were enrolled and randomized into two groups. In ropivacaine group (n = 26) the patients received 0.187% ropivacaine and fentanyl 3.2 microg x ml(-1) for postoperative epidural analgesia. In levobupivacaine group (n = 26) the patients received 0.187% levobupivacaine and fentanyl 3.2 microg ml(-1). Visual analogue scale (resting pain and pain on mobilization), the amount of rescue analgesics and epidural anesthesia related adverse events such as hypotension, nausea and vomiting were observed for 48 hours after surgery. RESULTS: There were no differences in visual analogue scale at all intervals between the two groups. In levobupivacaine group the patients used less amounts of rescue analgesics than ropivacaine group (P = 0.01). There were no differences in the incidences of postoperative hypotension, nausea and vomiting between the two groups. CONCLUSIONS: Both 0.187% ropivacaine and levobupivacaine similarly provide appropriate postoperative epidural analgesia for patients undergoing gynecological open abdominal surgery.
Assuntos
Amidas/farmacologia , Analgesia Epidural/métodos , Anestésicos Locais/farmacologia , Bupivacaína/análogos & derivados , Procedimentos Cirúrgicos em Ginecologia , Dor Pós-Operatória/tratamento farmacológico , Adulto , Bupivacaína/farmacologia , Feminino , Humanos , Levobupivacaína , Período Pós-Operatório , RopivacainaRESUMO
The aim of the present study was to determine the effect of low-dose remifentanil on the monitoring quality of the Bispectral index for mechanically ventilated patients. Twelve patients who underwent elective surgery and required mechanical ventilation post-operatively were enrolled in this study with written informed consent. Eligible patients were divided into two groups. Patients in the remifentanil group received low-dose remifentanil (0.05-0.125 µg/kg/min) and propofol (1-3 mg/kg/h). Patients in the control group received propofol (1-3 mg/kg/h). Levels of sedation were evaluated by both the Richmond Agitation Sedation Scale (RASS) and BIS monitor (A2000-XP, version 4.0, Aspect Medical Systems, Newton, USA). Monitoring quality was assessed by a correlation between RASS and BIS values. These values were assessed by single regression analysis and a P value of <0.05 was considered significant. There was a significant correlation between RASS and BIS values (P = 3 × 10(-12), R (2) = 0.67) in the remifentanil group, but not in the control group (P = 0.50, R (2) = 0.057). The administration of low-dose remifentanil makes BIS a more precise tool for sedated patients under mechanical ventilation in the ICU.
Assuntos
Sedação Consciente , Monitores de Consciência , Hipnóticos e Sedativos/administração & dosagem , Unidades de Terapia Intensiva , Piperidinas/administração & dosagem , Respiração Artificial , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Propofol/administração & dosagem , RemifentanilRESUMO
An 86-year-old woman with low cardiac function was scheduled to undergo hip fracture surgery. Preoperative electrocardiogram showed complete left bundle brunch block, first degree atrioventricular block, left axis deviation and bigeminy. However, her electrocardiogram had changed to complete atrioventricular block on arrival at operating theater. ACC/AHA guideline on perioperative cardiovascular evaluation and care for non cardiac surgery indicates the assessment of both the urgency of the surgery and cardiac complications. Because complete atrioventricular block is classified to "active cardiac conditions", we decided to postpone the surgery for more detailed evaluation and treatment of cardiac conditions. In spite of the discontinuation of digoxin and carvegilol, complete atrioventricular block continued for a week, and the permanent pacemaker was inserted. The surgery was performed 2 weeks following the insertion of the pacemaker without any problems under combined general and lumbar epidural anesthesia.
Assuntos
Bloqueio Atrioventricular/diagnóstico , Bloqueio Atrioventricular/terapia , Fraturas do Quadril/cirurgia , Salas Cirúrgicas , Marca-Passo Artificial , Cuidados Pré-Operatórios , Período Pré-Operatório , Idoso de 80 Anos ou mais , Anestesia Epidural , Anestesia Geral , Eletrocardiografia , Feminino , Humanos , Guias de Prática Clínica como AssuntoRESUMO
We report a man with severe dilated cardiomyopathy with an implantable cardioverter-defibrillator (ICD) who underwent sigmoidectomy. During the operation, the defibrillation function of the ICD has been stopped to prevent malfunction caused by electrocautery artifacts, and the electrodes of the external defibrillator were placed on the chest wall. Pulmonary artery catheter was inserted under X-ray imaging to prevent the interference between ICD leads and the catheter. Anesthesia was maintained with combined general and thoracic epidural anesthesia. In order to prevent the afterload increase, both milrinone and carperitide were administered. Fluid resuscitation was also performed to maintain circulating blood volume. As a result of the management, patient has not exhibited any heart failure.
Assuntos
Anestesia Geral/métodos , Cardiomiopatia Dilatada/complicações , Cardiomiopatia Dilatada/terapia , Desfibriladores Implantáveis , Neoplasias do Colo Sigmoide/cirurgia , Idoso , Colo Sigmoide/cirurgia , Humanos , MasculinoRESUMO
A 60-year-old female with multiple sclerosis (MS) and supranuclear palsy (PSP) was scheduled for right eye iridotomy, left eye phaco emulcification aspiration and insertion of the intraocular lens. Her medical conditions included prolonged immobility, spastic contracture, and a history of convulsion. She was administered with L-dopa, tizanidine, bacrofen, and dantrorane. Anesthesia was induced with propofol 50 mg and fentanyl 25 microg intravenously, and inhalation of oxygen and 1% sevoflurane. Tracheal intubation was performed without neuromuscular blocking agents. Anesthesia was maintained with inhalation of oxygen-air (Fi(O2) 0.4) and 1-1.5% sevoflurane, combined with regional anesthesia. Supplemental fentanyl was administered as needed. The bispectral index (BIS) was monitored and kept between 40 and 60. The operation proceeded uneventfully. After discontinuation of anesthetic agents, she awoke immediately and the BIS index returned to the pre-induction level. Neither neurological disturbances nor unexpected event were observed postoperatively. In patients with MS, it is important to remember the possibility of drugs moving into the central nervou system easily due to the disturbance of the blood-brai barrier. Patients with PSP are usually medicated wit. various medicines which have possibility of interactin with anesthetics. Therefore, we used least anesthetic as possible. In this case, monitoring of BIS seemed to be useful to maintain the minimum sevoflurane concen trations needed.
Assuntos
Anestesia Geral/métodos , Esclerose Múltipla/complicações , Paralisia Supranuclear Progressiva/complicações , Feminino , Glaucoma/cirurgia , Humanos , Pessoa de Meia-Idade , FacoemulsificaçãoRESUMO
BACKGROUND: Associated laryngeal paralysis is a clinical condition merged with other cranial nerve disorders associated with vocal cord paralysis. It is a rare complication in patients after general anesthesia. Here, we report our experience with a patient who developed associated laryngeal paralysis after oral surgery. CASE PRESENTATION: A healthy 31-year-old man underwent extraction of horizontally impacted wisdom teeth in the bilateral mandible under general anesthesia. During the surgery, no significant changes in respiratory and cardiovascular parameters or neurosurgical abnormalities occurred. After the surgery, the patient was diagnosed with aspiration pneumonia. Furthermore, the results of otorhinolaryngological and neurological examinations led to a diagnosis of a combination of bilateral glossopharyngeal and vagus nerve paralysis, right recurrent nerve paralysis, and right hypoglossal nerve paralysis. In this case, seriously associated peripheral laryngeal paralysis with repeated episodes of aspiration pneumonia improved in approximately 6 months with rehabilitation and vitamin B12 administration, and no complications remained. CONCLUSIONS: We suggest that the anesthesiologist should take care of each procedure minutely. It is important to diagnose cases of nerve palsy as soon as possible to reduce the damage. Having had experience with this case, we believe sharing our experience with anesthesiologists is important.
RESUMO
PURPOSE: It has been reported some patients have opened eyes with low bispectral index (BIS) values immediately following electroconvulsive therapy (ECT). We investigated the time course of the recovery from amnesia and BIS values. METHODS: Five patients with depression requiring repeated ECT procedures were enrolled. The patients were asked to recall an object presented prior to anesthesia at four specific points (prior to induction, upon regaining consciousness following ECT, when they returned to their ward, and when their BIS values had returned to pre-anesthetic levels). BIS data were recorded continuously until BIS values returned to the pre-anesthetic levels at their ward. The area under a receiver-operating characteristic (ROC) curve was used to detect associations between the BIS values and disturbance of memory function. RESULTS: A total of 41 ECT stimuli were administered. After returning to their ward, patients generally fell asleep, with BIS values of between 50 and 70, and they woke up 1-2 h later. All the patients could recall the presented object prior to anesthesia and when the BIS values had returned to pre-anesthetic levels. The area under the ROC curve for the detection of memory disturbance was 0.902. CONCLUSION: The present study demonstrated a high frequency of patients falling asleep and the frequent occurrence of prolonged periods of low BIS values following ECT. The results of memory testing showed that ECT procedures resulted in amnesia. The ROC curve findings suggest a strong association of memory disturbance with BIS values. In conclusion, patients generally fell asleep, with low BIS values, for 1-2 h after ECT, and a prolonged period of impairment of memory formation was associated with low BIS values.
Assuntos
Anestesia , Eletroconvulsoterapia/efeitos adversos , Eletroencefalografia/efeitos dos fármacos , Transtornos da Memória/etiologia , Transtornos da Memória/psicologia , Convulsões/fisiopatologia , Adulto , Idoso , Período de Recuperação da Anestesia , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Curva ROC , Reconhecimento Psicológico/fisiologia , Adulto JovemRESUMO
We present a life-threatening case of hemothorax resulting from right brachiocephalic vein perforation during right internal jugular vein catheterization. We considered that the guidewire had punctured the right brachiocephalic vein extraluminally and the catheter inserted over the guidewire had enlarged the size of the perforation. Despite the use of proper technique, an angle-tip guidewire may perforate the venous wall. Therefore, when there is negative aspiration after central venous catheterization, it is important to perform an emergency chest radiograph before proceeding with surgery; it is also important not to use an angle-tip guidewire.
Assuntos
Veias Braquiocefálicas/lesões , Cateterismo Periférico/efeitos adversos , Hemotórax/etiologia , Veias Jugulares , Idoso , Aneurisma da Aorta Abdominal/cirurgia , Perda Sanguínea Cirúrgica , Hemotórax/diagnóstico por imagem , Hemotórax/terapia , Humanos , Masculino , RadiografiaRESUMO
A case of accidental total spinal anesthesia was presented. A 47-year-old woman was scheduled for a total abdominal hysterectomy. An epidural catheter was inserted at the L1-2 interspace and 10 ml of 1% ropivacaine was injected. Following surgery, the patient did not regain consciousness and we confirmed total spinal anesthesia because of the cerebrospinal fluid leak through the epidural catheter. Therefore propofol was administered again until the recovery of sufficient spontaneous breathing confirmed approximately 3 hours following administration of ropivacaine, and patient was extubated. No neurologic deficits could be detected.
Assuntos
Amidas/efeitos adversos , Anestesia Epidural/efeitos adversos , Raquianestesia , Cateterismo/efeitos adversos , Espaço Epidural , Erros Médicos , Amidas/administração & dosagem , Anestesia Geral , Feminino , Humanos , Histerectomia , Pessoa de Meia-Idade , Prognóstico , Propofol/administração & dosagem , RopivacainaRESUMO
BACKGROUND: The prediction of the hypnotic states is useful to maintain the adequate anesthesia. During propofol anesthesia, the respiratory depression has been documented in a dose-dependent manner. Therefore, we investigated whether the respiratory depression under the spontaneous breathing reflected the estimated effect site propofol concentrations (Cp) in a dose-dependent fashion. METHODS: We enrolled 12 patients for elective lower limb surgery under combined subarachnoid anesthesia and propofol sedation. The respiratory parameters and BIS were measured at the Cp of 5 microg x ml(-1) followed by the 0.5 microg x ml(-1) decrements until the patients' movement. Effective indices to predict patients' movement were determined by receiver-operator characteristics. RESULTS: The significant correlations within a particular patient between the respiratory parameters and Cp were observed, although those were not between the patients. An EtCO2 of 53 mmHg or greater represents a clinically determinant condition for non-movement of the patients. CONCLUSIONS: We concluded that the respiratory parameters during spontaneous breathing were useful indices to predict the changes in the effect site propofol concentrations and to maintain the adequate anesthetic levels.
Assuntos
Anestesia Geral/métodos , Anestésicos Intravenosos , Propofol , Respiração/efeitos dos fármacos , Adulto , Idoso , Raquianestesia , Dióxido de Carbono/sangue , Procedimentos Cirúrgicos Eletivos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Propofol/administração & dosagem , Curva ROCRESUMO
BACKGROUND: The effect of nitrous oxide either as a sole agent or with volatile anesthetic agents on the central nervous system has been well studied. However, it has not been clarified during various levels of propofol anesthesia. We therefore evaluated the effect of nitrous oxide on the central nervous system using bispectral index (BIS) and suppression ratio (SR) under various levels of propofol anesthesia. METHODS: Twelve patients were enrolled for the study. After the administration of subarachnoid block, propofol was infused using a stepped down series (effect site concentration of 5, 4, 3 microg x ml(-1)) for 20 minutes. After obtaining BIS and SR at each concentration, nitrous oxide was added. RESULTS: When 67% of nitrous oxide was added to the estimated effect site propofol concentration of 5 microg x ml(-1), BIS decreased and SR increased indicating that the nitrous oxide had a depressant effect on the central nervous system. On the other hand, nitrous oxide combined with 3 or 4 microg x ml(-1) of propofol did not cause significant changes in BIS and SR, suggesting that nitrous oxide did not have a suppressive effect. CONCLUSIONS: We conclude that nitrous oxide has different effects on BIS according to their basal propofol concentrations.
Assuntos
Anestesia Intravenosa , Encéfalo/fisiologia , Eletroencefalografia/efeitos dos fármacos , Óxido Nitroso/farmacologia , Propofol , Adulto , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Feminino , Humanos , Masculino , Propofol/administração & dosagem , Propofol/sangue , Procedimentos Cirúrgicos OperatóriosRESUMO
Marshall-Smith syndrome (MSS) is a rare clinical disorder, characterized by accelerated skeletal maturation, facial anomalies, failure to thrive and death in early infancy due to respiratory complications. We experienced the difficult airway case with MSS. A 4-year-old boy underwent tenosynovectomy for the snapping finger. Although his upper airway was diagnosed as almost normal on the fiber-optic laryngoscope examination, he frequently showed pharyngeal collapse during sleep. Anesthesia was induced and maintained with N2O-O2-sevoflurane using oral-airway without muscle relaxants. But, when we inserted the laryngoscope in order to clarify the existence of the difficult intubation, we could only see a part of the epiglottis. We concluded that we must treat MSS as difficult airway and intubation, even if in the mild case of MSS.
Assuntos
Anormalidades Múltiplas , Anestesia Geral/métodos , Anormalidades do Sistema Respiratório , Doenças do Desenvolvimento Ósseo , Pré-Escolar , Face/anormalidades , Articulações dos Dedos/cirurgia , Transtornos do Crescimento , Humanos , Intubação Intratraqueal , Masculino , Transtornos Psicomotores , Síndrome , Tendões/cirurgia , Tenossinovite/cirurgiaRESUMO
UNLABELLED: The effect of opioid administration on the bispectral index (BIS) during general anesthesia is controversial. Several investigators have reported BIS to be insensitive to opioid addition, whereas others have found a hypnotic response. We designed this study to examine the effect of remifentanil on BIS during combined regional/general propofol anesthesia under steady-state conditions. After Human Investigations Committee approval, 19 healthy ASA physical status I or II patients were enrolled in a prospective experimental design. Regional anesthesia was initiated and general anesthesia induced by using computer-assisted continuous infusion of propofol. Propofol was incrementally adjusted to a BIS of approximately 60. After 20 min at a stable propofol infusion rate, a remifentanil computer-assisted continuous infusion (effect-site target concentration of 0.5, 2.5, and then 10 ng/mL) was sequentially administered at stepped 15-min intervals. BIS decreased from 56 +/- 2 to 44 +/- 1, 95% spectral edge frequency from 17.9 +/- 0.5 Hz to 15.0 +/- 0.4 Hz, heart rate from 84 +/- 5 bpm to 62 +/- 4 bpm, and mean arterial blood pressure from 93 +/- 4 mm Hg to 69 +/- 3 mm Hg with increasing remifentanil concentration. A significant linear correlation between BIS, 95% spectral edge frequency, heart rate, and log (remifentanil effect-site) concentration was found. The change in baseline BIS was relatively modest but significant, suggesting that remifentanil has some sedative/hypnotic properties, or that it potentiates the hypnotic effect of propofol. IMPLICATIONS: This experiment identified a significant, dose-dependent decrease in bispectral index (BIS), 95% spectral edge frequency, heart rate, and mean arterial blood pressure with increasing remifentanil dose. The change in baseline BIS was relatively modest but significant, suggesting that remifentanil has some sedative/hypnotic properties, or that it potentiates the hypnotic effect of propofol.