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On-line version ISSN 1806-907X
Rev. Bras. Anestesiol. vol.54 no.2 Campinas Mar./Apr. 2004
Anesthetic procedure for balneotherapy of burned patients: prospective evaluation of 2852 cases*
Conducta anestésica en balneoterapia de pacientes quemados: evaluación prospectiva de 2852 procedimientos
Fernando Antônio de Freitas Cantinho, TSA, M.D.I; Fernando Guedes Santos, M.D.II; Antônio Carlos Pereira da Silva, TSA, M.D.III
IInstrutor do Centro
de Ensino e Treinamento do Hospital do Andaraí
IIAnestesiologista do Hospital do Andaraí
IIIChefe da Clínica de Anestesiologia e Responsável pelo Centro de Ensino e Treinamento do Hospital do Andaraí
BACKGROUND AND OBJECTIVES: Deep
analgesia of burned patients needing daily care of their injuries is a field
where references are very scarce in the literature. This study aimed at evaluating
balneotherapy anesthetic technique in 2852 procedures.
METHODS: A one-year period prospective evaluation was performed on sedative and analgesic alternatives adopted by anesthesiologists. Age, weight, gender, burned surface area (BSA), drugs and doses used, duration, monitoring, number of sessions by patient, and complications were recorded. Samples was divided in four groups according to age: group A, < 10 years; group B, 11 to 17 years; group C, 18 to 65 years; group D, > 65 years, and the results were compared.
RESULTS: There have been 2852 balneotherapy sessions performed in 134 patients: Group A = 743 sessions in 42 patients; Group B = 354 sessions in 16 patients; Group C = 1573 sessions in 68 patients; Group D = 182 sessions in 8 patients. Throughout the study, the intravenous S(+)-ketamine as single agent was used in 116 sessions. The intravenous S(+)-ketamine with midazolam was used in 631 sessions. The intravenous S(+)-ketamine with midazolam and fentanyl was used in 1562 sessions. The muscular S(+)-ketamine as single agent was used in 188 sessions, being 173 in group A. The propofol was associated in 149 sessions. The racemic ketamine was used in 142 sessions. The alfentanil, as some other agents, was seldom used. Sessions lasted 29.3 ± 10.6 minutes and the increased weight and/or BSA was correlated to significantly longer sessions. There have been 30 cases of SpO2 below 90%, being 3 cases (0.59%) in patients receiving intravenous S(+)-ketamine and midazolam, and 24 cases (1.93%) in patients receiving intravenous S(+)-ketamine, midazolam and fentanyl (p = 0.039). There has been one case of cardiac arrest in moribund patient, who was resuscitated and the session was completed.
CONCLUSIONS: The S(+)-ketamine, midazolam and fentanyl were the most common agents, being the S(+)-ketamine the major agent. Anesthetic techniques were safe and effective.
Key Words: ANESTHESIA; DISEASES: burn; THERAPY: balneotherapy
JUSTIFICATIVA Y OBJETIVOS:
La analgesia profunda en el paciente quemado, que necesita de cuidados diarios
de las lesiones, constituye un campo de actuación del anestesiologista
en que las referencias de conducta aun son muy escasas. El objetivo de este
estudio fue evaluar la conducta anestésica en balneoterapia de pacientes
quemados en 2852 procedimientos.
MÉTODO: Fue realizada evaluación prospectiva de las alternativas de analgesia y sedación utilizadas por anestesiologistas, en el período de 1 año. Edad, peso, sexo, superficie corporal quemada (SCQ), drogas y dosis utilizadas, duración, monitorización, número de procedimientos por paciente y complicaciones, fueron registradas. Para la análisis de los resultados, la muestra fue dividida en grupos: grupo A, con edad hasta 10 años; grupo B, 11 a 17 años; grupo C, 18 a 65 años; grupo D, mayores de 65 años, los datos fueron comparados.
RESULTADOS: Fueron 2852 procedimientos realizados en 134 pacientes. En el grupo A, fueron 743 procedimientos en 42 pacientes; en el grupo B, 354 procedimientos en 16 pacientes; en el grupo C, 1573 procedimientos en 68 pacientes; en el grupo D, 182 procedimientos en 8 pacientes. En toda la muestra, la S(+)-cetamina por vía venosa, como agente único, fue usada en 116 casos. La S(+)-cetamina, asociada al midazolam, por vía venosa, fue usada en 631 casos. La S(+)-cetamina, asociada al midazolam y al fentanil, por vía venosa, fue usada en 1562 casos. La S(+)-cetamina por vía muscular, como agente único, fue utilizada en 188 casos, siendo 173 en el grupo A. El propofol fue asociado en otros 149 casos. La cetamina racémica fue usada en más 142 casos. El alfentanil, como algunos otros agentes, fue poco usado. La duración de los procedimientos fue de 29,3 ± 10,6 minutos; mayor peso y SCQ se correlacionaron con el aumento significante de la duración. Hubo 30 casos de disminución de la SpO2 abajo de 90%, siendo 3 casos (0,59%) en el subgrupo que recibió S(+)-cetamina y midazolam por vía venosa, y 24 casos (1,93%) en el que recibió S(+)-cetamina, midazolam y fentanil por la misma vía (p = 0,039). Hubo un caso de parada cardíaca en paciente moribundo, que fue recuperado, prosiguiéndose el baño hasta el final.
CONCLUSIONES: La S(+)-cetamina, el midazolam y el fentanil fueron los agentes más utilizados, siendo la S(+)-cetamina el principal agente. Las técnicas anestésicas utilizadas se mostraron seguras y eficaces.
The treatment of extensively burned patients wounds is very often a challenge when it comes to analgesia and sedation. It is among the injuries promoting the highest degree of painful stimulation and acts as a promising environment for microorganism development. Besides, this kind of patients have a possibility of associations with others systemic diseases, that results in a complex pathophysiological situation. This pathophysiological state trigger pharmacokinetic changes. It is accepted that in presence of such changes, analgesic doses for burned patients should be individually defined in a case-by-case basis 1.
Periodic wound care is critical for the satisfactory evolution of burned patients. However, pain caused by such procedure very often goes beyond bearable thresholds during superficial analgesia techniques. Severe pain disturbs or inhibits the attention of those in charge of care and, as a consequence, most effective care is not achieved. The highest attention given to burned children analgesia is understandable, but it is a severe mistake to assume that pain in burned adults should be borne with superficial analgesia alone. The necessary care for thorough wound care requires the use of potent analgesics regardless of patients' age.
In our hospital, by request of the Burned Patients Treatment Center (CTQ) staff, the members of department of Anesthesiology has become part of balneotherapy sessions to induce sedation and analgesia since October 1999. In the search for references, we have found a major gap in the literature. We have also observed that it is impossible to regularly use the some monitoring equipment, such as the cardioscope.
In face of the high number of procedures and absence of similar literature we have developed a project to prospectively evaluate, during one year, the technical alternatives used by our Department of Anesthesiology. This study aimed at evaluating our anesthetic management of 2852 balneotherapy procedures for burned patients.
After the Ethics Committee approval, all balneotherapy procedures performed in CTQ in the period June 1, 2001 to May 31, 2002 were evaluated. Anesthesiology Department physicians were informed about the project and were asked to carefully fill out anesthetic records which would be our data source. The authors have not interfered with the techniques used by other anesthesiologists of the Department. Paper records were weekly copied to electronic records developed with the Epi-Info 6 program. The colleague filling it out could be asked to clarify any doubts arising from paper records. Age, weight, gender, burned surface area (BSA), drugs and doses used, duration, monitoring, number of procedures per patient and complications were recorded. In the first semester, only total doses used were recorded; in the second semester, we started to record also the initial doses, that is, those allowing the beginning of wound care.
Balneotherapy is a procedure performed in special CTQ room, where pulse oximeter and ventilatory assistance are available. Oximeter sensor is preferably pediatric, which favors its protection against water and antiseptics with a glove finger. Cardioscope and defibrillator are available for specific cases. Balneotherapy is performed on stainless steel tables. Procedures are performed in the morning with patients fasting since the night before. When patients are admitted to bathing table, their general status is evaluated and information is shared with Burned Patients Center staff. Venous access is checked and oximeter sensor is installed. Bath and wound care are performed by the nursing staff under supervision of the medical team. Very often, oral hygiene is performed on the bathing table before starting drug administration. The whole body, and not only burned areas, is brushed and receives anti-septic solution. Often, minor débridements are performed by surgeons. Since débridements can be frequent, they prevent the need for major débridements in the operating room. Procedures such as superficial or deep venous access replacement, removal of autogenous graft stitches, abscess drainage, among others, are associated to the bath.
To evaluate results, sample was divided in four groups according to age: Group A = < 10 years of age; Group B = 11 to 17 years of age; Group C = 18 to 65 years of age; Group D = > 65 years of age. Analysis of Variance (ANOVA) was used to compare parametric values and Chi-square test was used to compare non-parametric data being significant p < 0.05.
This study involved 2852 procedures performed in 134 patients. Age distribution is shown in table I. Age extremes were 4 months and 89 years. There has been wide variation in the number of procedures each patient was submitted to (21.1 ± 19.1; extremes: 1 - 102 procedures/patient; median = 15.5). Participated in analgesia and sedation 41 anesthesiologists and 19 physicians in specialization.
Mean procedure duration throughout the sample and in each age group is shown in table I. Group A duration (24.2 ± 9 minutes) was shorter as compared to Group B (28.8 ± 9.8 minutes). Group B duration was shorter as compared to Group C (31.6 ± 10.6 minutes). Duration was similar for Groups C and D (31.1 ± 9.7 minutes). BSA in each age group is also shown in table I. The figure 1 shows the significant correlation throughout the sample between BSA and increased procedure duration. The figure 2, in spite of smoother regression line slope, shows significant correlation between increased weight and longer duration.
Basic sedation and analgesia objective was to maintain patients painless and relaxed during the procedure; hypnosis was not mandatory. Eye opening and speech were frequent with ketamine.
Intravenous S(+)-ketamine as single agent was used in 116 procedures, being 93 in Group A. Initial dose was 1.608 ± 1.084 mg.kg-1 and total dose was 2.162 ± 1.170 mg.kg-1.
Intravenous midazolam and S(+)-ketamine were used in 631 procedures; doses used in different age groups are shown in table II. Intravenous midazolam, S(+)-ketamine and fentanyl were used in 1562 procedures; doses are shown in table III. Muscular S(+)-ketamine as single agent was used in 186 procedures, being 173 in Group A; dose was 4.3 ± 1.5 mg.kg-1. Propofol was associated to different drug combinations in 149 procedures in a total dose of 2.3 ± 1.6 mg.kg-1.
Racemic ketamine was used in 142 procedures. When associated to midazolam (n = 48) doses were similar to those of the association S(+)-ketamine and midazolam. When associated to midazolam and fentanyl (n = 88) there have been higher midazolam (p = 0.0006), fentanyl (p = 0.06) and racemic ketamine doses as compared to the isomeric form (p = 0.01).
In comparing the group receiving intravenous midazolam and S(+)-ketamine with the group receiving intravenous midazolam, S(+)-ketamine and fentanyl, it has been observed that fentanyl has allowed for lower midazolam and S(+)-ketamine doses.
Alfentanil was used in 17 procedures to replace fentanyl. Other drugs used were haloperidol (3 cases), droperidol (2 cases) and meperidine (2 cases). Dipirone for postoperative analgesia was used in 1344 procedures (dose = 34.1 ± 10.6 mg.kg-1).
Pulse oximetry has been recorded in 2233 procedures (78.3%). There have been 30 cases of respiratory depression; 2 cases of apnea and 28 cases of persistent SpO2 decrease below 90% and requiring oxygen under facial mask. Among 504 oximeter-monitored procedures where intravenous midazolam and S(+)-ketamine were used, there have been 3 cases of respiratory depression (0.59%). Among 1238 oximeter-monitored procedures where intravenous midazolam, S(+)-ketamine and fentanyl were used, there have been 24 cases of respiratory depression (1.93%). These groups were homogeneous in other variables such as age, weight, procedure duration, burned body surface area and gender. Fentanyl addition has shown significant correlation with higher incidence of respiratory depression (p = 0.039).
One male patient aged 14 years with 22% BSA submitted to 35 balneotherapy sessions has presented trunk, face and/or neck flare during 11 sessions. Trying to identify the triggering agent of possible allergic reaction, either midazolam, or S(+)-ketamine or fentanyl were withdrawn session after session. None of the three drugs could be characterized as the triggering agent. Reaction was also not caused by the anti-septic solution because it would appear before its use. Reaction was localized without associated systemic effect. Patient had satisfactory evolution and was discharged without identification of the cause of the event.
There has been one case of cardiac arrest in a 53-year old patient with 63% BSA. Drugs used were intravenous midazolam and S(+)-ketamine. Oximeter was ineffective in recording pulse wave during the procedure and cardiac arrest was established 30 minutes after beginning of analgesia. Patient was resuscitated and the procedure continued until the end. Patient evolved to death 3 days after. No other case has presented respiratory depression needing tracheal intubation.
Among different databases queried (Medline, Ovid, LILACS, SciELO, Cochrane Library), there has been major scarcity of the best description of anesthetic techniques used for burned patients balneotherapy. Acupuncture 2, massage 3, hypnosis or other psychological approaches 4-8 are non-pharmacological alternatives. Alfentanil 9.10, midazolam 11, propofol 12,13, sevoflurane 14 and more often ketamine 13,15-17 are drugs almost always used in association.
Sessions are daily and so, suppression of one meal could negatively impact nutritional support of those patients. So, there is a concern that patients could receive food minutes after balneotherapy, what has been made possible by our techniques.
Ketamine has four characteristics which make it a valuable balneotherapy agent: (1) potent analgesic; (2) minor or no respiratory depression; (3) does not need complex devices for its administration, needing just syringe and needle; (4) fast onset and high efficacy even by muscular route. The association of ketamine to other drugs depressing ventilation impairs this profile of respiratory safety. Hallucination and psychomotor agitation are major limitations for the use of this drug; the association of benzodiazepines decreases agitation. Some authors admit that S(+)-ketamine has advantages over the racemic form, among them less psychedelic properties 18-20. We have not found in the literature studies using S(+)-ketamine for burned patients analgesia.
Intravenous fentanyl associated to midazolam and S(+)-ketamine has increased the risk for respiratory depression. This finding has more statistical than clinical value, because there has been no related complication impossible to be solved with oxygen under facial mask. The higher incidence of respiratory depression with fentanyl has not been perceived before statistical analysis. These findings grant safety to the association of intravenous fentanyl, S(+)-ketamine and midazolam and justify its routine use.
Propofol is also gaining space in balneotherapy. It allows for lower doses of other agents, such as midazolam, with the potential advantage of patients presenting a higher level of awareness after the procedure, providing, among other advantages, the condition of early feeding. More midazolam and less propofol is still the choice for most anesthesiologists working in the CTQ. We have observed major propofol action in decreasing agitation and hallucination during the procedure, with advantages over midazolam.
It is important that drug administration follows the degree of painful stimulation. This implies administering drugs only when everything is ready to start wound care. The administration of the same dose to the same patient in the absence of painful stimulation may promote a level of respiratory depression which would not be present if the nursing staff would be already taking care of the wounds.
High statistical correlation has been found in increased procedure duration with higher BSA and weight. Clinically it is worth mentioning that in infants or neonates with small BSA, the procedure is normally fast (10 to 15 minutes), being initial doses enough to complete the procedure. In the other extreme, in obese adults with large BSA, very often with co-morbidity unrelated to the burn, the procedure tends to be longer, needing more than one additional dose, thus being a more complex procedure. Three or four minutes which have determined high statistical difference due to sample size, are of minor value for analgesic approach.
The difficulty in monitoring such patients has been and still is a reason of concern for anesthesiologists. There is no way to strictly comply with issues defined in standards ruling the anesthetic practice, such as those defined by Resolution 1363 of the Federal Council of Medicine. So, there might be unique difficulties if there is any medical-legal claim. For sure, anesthesiologists' role in balneotherapy deserves special consideration and is a subject deserving further discussions. We understand that pulse oximeter, for allowing the follow up of cardiac rate and rhythm, plays part of the cardioscope role. Nevertheless, cardioscope should always be easily available. During balneotherapy sessions, when major changes in rate and/or rhythm are detected, the session should be interrupted for the effective use of cardioscopy. So, sessions should continue or be interrupted according to the evaluation.
There is another unique feature in balneotherapy monitoring, almost always absent in operating room patients. Chest is always uncovered and chest expansion observation is a major anesthesiologist ally, especially when the oximeter is unable to record pulse wave. We prefer to observe expanded chest to oximeter wave and oximetry value.
There is no question about the limitation of ketamine in hypertensive and/or ischemic patients. This is another topic of wide and complex discussion. Superficial analgesia may induce more severe hypertension than that caused by ketamine. Opioids, in the doses needed for satisfactory analgesia, induce respiratory depression which may imply increase in PaCO2 and also severe cardiovascular involvement. Our preference for those patients has been higher opioid doses, but we do not necessarily rule out ketamine to assure analgesia, which should be the best protection for the cardiovascular system.
The repeated use of anesthetic drugs in patients who very often present with severe systemic changes deserves special consideration. After more than 3 years using the described techniques, we still lack information pointing to complications caused by the repeated administration of the drugs. However, care is recommended and more time and/or specific studies are necessary to identify potential complications.
Knowing the importance of proper burn wound care for patients' best evolution and knowing the severe pain caused by such care makes balneotherapy anesthesia a highly gratifying activity for the physician, the major objective of who is to relief pain in an effective and safe way.
In the conditions of our study, anesthetic techniques have shown to be safe and effective for burned patients balneotherapy.
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Dr. Fernando Antônio de Freitas Cantinho
Rua Professor Fernando Raja Gabaglia, 182 - Casa 1 Jacarepaguá
22750-660 Rio de Janeiro, RJ
Apresentado (Submitted) em 03 de
abril de 2003
Aceito (Accepted) para publicação em 01 de julho de 2003
* Recebido do (Received from) Centro de Ensino e Treinamento em Anestesiologia do Hospital do Andaraí, Rio de Janeiro, RJ