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Print version ISSN 0034-7094
Rev. Bras. Anestesiol. vol.52 no.1 Campinas Jan./Feb. 2002
Propofol and alfentanil sedation for extracorporeal shock wave lithotripsy *
Sedación con propofol y alfentanil para litotripsia extracorpórea por ondas de choque
José Roberto Nociti, TSA, M.D.I; Sérgio Neves Zuccolotto, TSA, M.D.II; Carlos André Cagnolati, M.D.III; Antônio Carlos Moura Oliveira, M.D.IV; Maurício Mahalem Bastos, M.D.IV
IIInstrutor do CET/SBA
IIIAnestesiologista da Santa Casa de Misericórdia de Ribeirão Preto, SP
IVME do CET/SBA
BACKGROUND AND OBJECTIVES:
This non comparative study aimed at investigating optimal propofol and alfentanil
doses used for sedation during extracorporeal shock wave lithotripsy (ESWL)
as well as the time elapsed for hospital discharge.
METHODS: Participated in this study 24 consecutive outpatients of both genders, physical status ASA I or II, submitted to ESWL under intravenous sedation. Sedation consisted of propofol (initial dose of 1 mg.kg-1 followed by continuous infusion with variable speed), and alfentanil (initial dose of 15 µg.kg-1 followed by additional 5 µg.kg-1 boluses according to clinical needs). Non invasive SpO2, SBP, DBP, and HR were monitored, and hospital discharge was provided according to Kortillas criteria for outpatient surgeries.
RESULTS: Mean procedure duration was 46.8 ± 12.8 minutes. Mean total propofol and alfentanil doses were 59.0 ± 17.9 µg.kg-1.min-1 and 0.38 ± 0.14 µg.kg-1.min-1, respectively. Time for hospital discharge was 60 min or less in 58.3% of patients; 61 to 90 minutes in 20.9%; 91 to 120 minutes in 12.5%; and more than 120 minutes in 8.3%. There has been at least one episode of low arterial blood saturation (SpO2 £ 85%) in 45.8% of patients followed by quick reversion after 100% oxygen supply.
CONCLUSIONS: Propofol and alfentanil in the doses reported are practical, effective, and safe for ESWL anesthesia, provided respiratory and cardiovascular parameters are monitored and devices for treating complications are readily avaiable.
Key Words: DIAGNOSIS AND THERAPEUTIC PROCEDURES: extracorporeal lithotripsy; HYPNOTICS: propofol; SEDATION: venous
JUSTIFICATIVA Y OBJETIVOS:
Este estudio no-comparativo tiene por objetivo pesquisar las dosis adecuadas
de propofol y alfentanil en sedación para litotripsia extracorpórea
por ondas de choque (LEOC) bien como el tiempo necesario para el alta hospitalar.
MÉTODO: Fueron observados 24 pacientes consecutivos de ambos sexos sometidos a LEOC en régimen ambulatorial, con estado físico ASA I ó II, bajo sedación por vía venosa con propofol en la dosis inicial de 1 mg.kg-1, seguida de infusión continua con velocidad variable, y alfentanil en la dosis inicial de 15 µg.kg-1, seguida de bolus adicionales de 5 µg.kg-1 conforme las necesidades clínicas. Monitorización de SpO2, PAS, PAD y FC por método no-invasivo y alta hospitalar conforme criterios propuestos por Kortilla para pacientes ambulatoriales.
RESULTADOS: La duración media de los procedimientos fue de 46,8 ± 12,8 minutos. Las dosis totales medias de propofol y de alfentanil fueron respectivamente de 59,0 ± 17,9 µg.kg-1.min-1 y 0,38 ± 0,14 µg.kg-1.min-1. Alta hospitalar en hasta 60 minutos en 58,3% de los casos; de 61 a 90 minutos en 20,9%; de 91 a 120 minutos en 12,5%; y más de 120 minutos en 8,3%. Ocurrió desaturación de la sangre arterial (SpO2 £ 85%) en por lo menos una ocasión en 45,8% de los pacientes, con rápida recuperación después de proporcionar oxígeno a 100%.
CONCLUSIONES: La sedación con propofol y alfentanil en las dosis relatadas para LEOC constituye método práctico, efectivo y seguro desde que adoptadas las medidas para monitorización y atendimiento a complicaciones cardiorrespiratorias que pueden ocurrir en el curso del procedimiento.
Extracorporeal shock wave lithotripsy (ESWL) is today the most popular method to treat high urinary tract calculi 1. It is a painful procedure and several anesthetic techniques have been used: epidural with both local anesthetics and/or opioids 2-4, local infiltration 5, intercostal blocks 6, general anesthesia 7 and intravenous sedation 8. With the introduction of new lithotripsy devices, several problems were attenuated and anesthesiologists are increasingly inducing sedation with intravenous agents associated to respiratory and hemodynamic monitoring 9. This non comparative study aimed at investigating adequate hypnotic (propofol) and opioid (alfentanil) doses for intravenous sedation as well as time for hospital discharge.
After the Hospitals Ethics Committee approval and their informed consent, participated in this study 24 consecutive patients scheduled for ESWL. Exclusion criteria were urinary tract infection and coagulopathies since these are considered absolute counterindications for ESWL 9. Patients observed a minimum of 8-hour fast, were not premedicated and were monitored with non invasive SpO2 (pulse oximetry), systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR).
Sedation was induced with intravenous propofol in an initial dose of 1 mg.kg-1 followed by continuous infusion (infusion pump) with variable speed, and alfentanil in an initial dose of 15 µg.kg-1 followed by additional 5 µg.kg-1 boluses, according to clinical needs. Propofol infusion speed was adjusted to maintain conscious sedation, characterized by: a) depressed consciousness, but not lost; b) response to verbal stimulation such as open your eyes, take a deep breath; and c) maintenance of airway protection reflexes. Alfentanil was administered in the presence of clinical signs of pain, tachycardia or hypertension.
Care was taken with airways and 100% oxygen under mask was administered whenever arterial blood saturation lowered to SpO2 £ 85%.
Hospital discharge was based on Kortillas criteria 10 for outpatient procedures (Chart I).
Adverse effects were recorded: hypotension (SBP decrease equal to or higher than 40% of control); bradycardia (HR £ 50 bpm); tachycardia (HR ³ 120 bpm); nausea and vomiting.
Patients demographics are shown in table I.
Mean procedure duration was 46.8 ± 12.8 minutes with variations shown in table II.
Mean total propofol dose (including initial dose) was 59.0 ± 17.9 µg.kg-1.min-1 (extremes 20.7 - 104.0). Mean total alfentanil dose (including initial dose) was 0.38 ± 0.14 µg.kg-1.min-1 (extremes 0.20 - 0.74).
Mean time for hospital discharge, considered as from the end of the procedure, was 74.1 ± 27.5 minutes with variations shown in table III. Among Kortillas hospital discharge criteria 10 widely used today in outpatient surgeries, special attention was given to well oriented patients in time and space; no evidence of respiratory depression, ability to dress and walk by themselves, absence of nausea and vomiting. Patients were observed in an adjacent room until discharge.
There has been at least one episode of low arterial blood saturation with SpO2 £ 85% in 11 patients (45.8%), followed by quick reversion after 100% oxygen supply. There have been hypotension and bradycardia in one patient (4.1%) with fast recovery after a single vasopressor dose.
Conscious sedation is currently the anesthetic technique of choice for routine ESWL due to the high satisfaction level of patients and brief hospital stay 8,11. To obtain the latter benefit, agents with relatively low distribution volumes and low plasma elimination half-life are necessary, as it is the case with propofol and alfentanil 12. Propofol has been used alone or in combination with nitrous oxide and other agents 13, always with satisfactory results. In our study, sedation with propofol and alfentanil was satisfactory and resulted in a relatively brief hospital stay. However, the technique does not rule out the monitoring of hemodynamic and especially respiratory parameters since there may be respiratory depression with arterial blood low saturation. One must bear in mind that such procedures are performed far from the operating center and all pieces of equipment necessary to maintain free airways and to administer oxygen must be at hands to be used in such situations.
We conclude that sedation with propofol and alfentanil in the doses reported for ESWL is practical, effective and safe, provided that monitoring measures are adopted and possible respiratory and circulatory complications inherent to the sedation technique are promptly treated.
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to Submitted for publication April 9, 2001 * Received from CET/SBA
da Santa Casa de Misericórdia de Ribeirão Preto, SP
Dr. José Roberto Nociti
Rua Stélio Machado Loureiro, 21 Alto da Boa Vista
14025-470 Ribeirão Preto, SP
Accepted for publication July 18, 2001
Submitted for publication April 9, 2001
* Received from CET/SBA da Santa Casa de Misericórdia de Ribeirão Preto, SP