304
ANESTH ANALG 1991;72:304-7
Patient-Controlled Sedation During Epidural Anesthesia woo Young Park,
MD,
and Patricia A. Watkins,
PARK WY, WATKINS PA. Patient-controlled sedation during epidural anesthesia. Anesth Analg 1991;72:30&7.
The purpose of this study was to evaluate the feasibility m d advantages or disadvantages, if any, of patient-controlled sedation compared with sedation administered by the anesthesiologist during surgical epidural anesthesia. Forty patients were divided at random into two groups with 20 patients in each group. Patients in group 1 received 0.5-1 .O mg intravenous midazolam and 25-50 pg intravenous fentanyl in increments administered by the anesthesiologist to achieve intraoperative sedation; patients in group 2 self-administered a mixture of midazolam (0.5 mg) and fentanyl (25 pg) in increments using an Abbott Lifecare PCA infuser to achieve sedation. Demographics of the patients, the types of surgery performed, doses of midazotam and fentanyl administered in a given period of time, and the level of sedation maintained during epidural anesthesia and surgery were similar in both groups. Patients in
Successful epidural anesthesia requires not only intraoperative relief of pain but also an adequately sedated, cooperative patient. To allay fear and anxiety and to ease any discomfort associated with the performance of the epidural block and/or the surgical procedure, sedatives and narcotics are often administered intravenously in the operating room by the anesthesiologist (1). It has been our clinical experience that, because of wide individual variations in response to sedatives and narcotics, over- or undersedation is not infrequent. In addition, there is considerable variation in the level of sedation desired by different patients. An occasional patient requests that he be fully awake during the entire procedure. Other patients request heavy sedation with total amnesia for the event. In recent years, patient-controlled analgesia (PCA) has become popular for postoperative pain control
CRNA
the self-administered group, however, rated their level of comfort during anesthesia and surgery higher than did those in the anesthesiologist-controlled sedation group. This could have been due to a positive psychological effect produced by allowing patients to feel that they have some control over their situation. The findings of this study indicate that patient-controlled sedation using a combination of midazolam and fentanyl is a safe and effective technique that provides intraoperative sedation ranked better by patients than that provided by anesthesiologists using the same drugs. More studies are, however, needed to determine the best choice of drug(s), the doses, the lock-out intervals, and the possible use of continuous infusion with pa tien t-con trolled sedation. Key Words: ANESTHETIC TECHNIQUES, EPIDURAL ANESTHESIA. HYPNOTICS, PATIENTCONTROLLED SEDATION.
(2,3). There is evidence that the pain can be better controlled by the self-administration of small, repetitive, on-demand, intravenous doses of narcotics using a PCA infuser than by the traditional timed intramuscular administration of these drugs (4-6). It has been also reported that midazolam can be given using a PCA infuser to provide anxiolysis in the intensive care unit (7). A logical extension of this form of analgesia or anxiolysis is to allow patients to find and maintain their own steady state of sedation by self-administration of sedatives and/or narcotics during surgery. This study was designed to evaluate the feasibility and advantages or disadvantages, if any, of patient-controlled sedation (PCS) compared with sedation provided by an anesthesiologist during surgery performed under epidural anesthesia.
Methods Supported in part by Abbott Laboratories. Received from the V.A. Medical Center and the Department of Anesthesiology, Georgetown University Medical School, Washington, D.C. Accepted for publication October 16, 1990. Address correspondence to Dr. Park, Chief of Anesthesiology, V.A. Medical Center, 50 Irving Street N.W., Washington, DC 20422. 01991 by the International Anesthesia Research Society 0003-2999/91/$3.50
Forty patients scheduled to have epidural anesthesia for proposed elective surgery of lower extremities or lower abdomen and who had no history of narcotic abuse were investigated. Patients were divided equally into two groups at random with 20 patients in
PATIENT-CONTROLLED SEDATION
each group. For sedation during anesthesia and surgery, patients in group 1 were given midazolam and fentanyl administered intravenously in divided doses at the discretion of the anesthesiologist. Patients in group 2 self-administered a mixture of midazolam and fentanyl intravenously using a PCA infuser. Permission to conduct this study was obtained from the hospital’s research review committee. After obtaining informed consent, patients were premedicated with 5-10 mg diazepam and/or 5-10 mg morphine. Morphine was administered intramuscularly and diazepam was administered either orally or intramuscularly approximately 1 h before surgery. On arrival in the operating room, the degree of sedation from premedication was rated jointly by the anesthesiologist assigned to the case and by the investigator using the ”Sedation Scale’’ (1-10, 1 = fully awake; 5 = moderate sedation: resting comfortably with eyes closed but responsive to verbal stimuli; 10 = heavy sedation: unresponsive to verbal stimuli but responsive to gentle tactile stimuli). An intravenous cannula was inserted and a blood pressure cuff, electrocardiogram electrodes, and a pulse-oxymetry probe were applied. If indicated, the anesthesiologist administered 0.5-1.0 mg midazolam and/or 25-50 pg fentanyl in increments intravenously in group 1 patients before performing the epidural block. Midazolam was administered for sedation, and fentanyl was used to treat pain (or discomfort). Patients in group 2, on the other hand, self-administered a mixture of midazolam and fentanyl in 2.5-mL increments (each milliliter containing 0.2 mg midazolam and 10 pg fentanyl) as desired using an Abbott Lifecare PCA infuser (Abbott Laboratories, North Chicago, Ill.). The PCA infuser was programmed to allow self-administration of 2.5 mL of the mixture of midazolam and fentanyl with a minimum of a 5-min obligatory lock-out interval between consecutive doses. When the patient was adequately sedated, he or she was placed in the lateral decubitus position on a horizontal operating room table. A #17 Tuohy needle was introduced through the second or third lumbar intervertebral space, and the epidural space was identified using ”loss of resistance” technique. With the bevel of the needle pointing cephalad, 3 mL of 1.5%-2.0% lidocaine or 0.5% bupivacaine, both with epinephrine (1:200,000), was injected. After 1 min, if there was no evidence of inadvertent subarachnoid or intravenous injection of the drug, an additional amount of the same local anesthetic was injected at the approximate rate of 1.0 mL/s. An epidural catheter was inserted if indicated, and the patient was then positioned for surgery. Oxygen (3 L/min) was administered by nasal cannula in the operating room.
ANESTH ANALG 1991;72:304-7
305
Table 1. Demographics of the Study Patients
Age (Yd Height (cm) Weight (kg)
Group 1 (n = 20)
Group 2 (n = 20)
P
59.6 2 16.7 175.6 & 8.1 78.5 2 14.8
56.3 k 10.4 172.5 2 7.9 79.8 k 13.9
NS NS NS
Values are expressed as mean 2 SD. Group I, anesthesiologist-controlled sedation; group 2, patientcontrolled sedation; NS, not significant.
Skin incision was made only after confirming the presence of an adequate level and intensity of epidural anesthesia for the proposed surgery. During the surgery, patients in group 1 had midazolam administered intravenously in increments for sedation and fentanyl to treat discomfort (or pain) as determined by the anesthesiologist. Patients in group 2 selfadministered a mixture of midazolam and fentanyl using a preprogrammed Abbott PCA infuser. At the end of surgery the total doses of midazolam and fentanyl given were calculated and the overall adequacy of the sedation during surgery was rated jointly by the anesthesiologist assigned to the case and the investigator using the aforementioned sedation scale. The patient was observed for any of the following complications during the study: (a) respiratory rate
ANESTH ANALG 1991;72:304-7
Patient-Controlled Sedation During Epidural Anesthesia woo Young Park,
MD,
and Patricia A. Watkins,
PARK WY, WATKINS PA. Patient-controlled sedation during epidural anesthesia. Anesth Analg 1991;72:30&7.
The purpose of this study was to evaluate the feasibility m d advantages or disadvantages, if any, of patient-controlled sedation compared with sedation administered by the anesthesiologist during surgical epidural anesthesia. Forty patients were divided at random into two groups with 20 patients in each group. Patients in group 1 received 0.5-1 .O mg intravenous midazolam and 25-50 pg intravenous fentanyl in increments administered by the anesthesiologist to achieve intraoperative sedation; patients in group 2 self-administered a mixture of midazolam (0.5 mg) and fentanyl (25 pg) in increments using an Abbott Lifecare PCA infuser to achieve sedation. Demographics of the patients, the types of surgery performed, doses of midazotam and fentanyl administered in a given period of time, and the level of sedation maintained during epidural anesthesia and surgery were similar in both groups. Patients in
Successful epidural anesthesia requires not only intraoperative relief of pain but also an adequately sedated, cooperative patient. To allay fear and anxiety and to ease any discomfort associated with the performance of the epidural block and/or the surgical procedure, sedatives and narcotics are often administered intravenously in the operating room by the anesthesiologist (1). It has been our clinical experience that, because of wide individual variations in response to sedatives and narcotics, over- or undersedation is not infrequent. In addition, there is considerable variation in the level of sedation desired by different patients. An occasional patient requests that he be fully awake during the entire procedure. Other patients request heavy sedation with total amnesia for the event. In recent years, patient-controlled analgesia (PCA) has become popular for postoperative pain control
CRNA
the self-administered group, however, rated their level of comfort during anesthesia and surgery higher than did those in the anesthesiologist-controlled sedation group. This could have been due to a positive psychological effect produced by allowing patients to feel that they have some control over their situation. The findings of this study indicate that patient-controlled sedation using a combination of midazolam and fentanyl is a safe and effective technique that provides intraoperative sedation ranked better by patients than that provided by anesthesiologists using the same drugs. More studies are, however, needed to determine the best choice of drug(s), the doses, the lock-out intervals, and the possible use of continuous infusion with pa tien t-con trolled sedation. Key Words: ANESTHETIC TECHNIQUES, EPIDURAL ANESTHESIA. HYPNOTICS, PATIENTCONTROLLED SEDATION.
(2,3). There is evidence that the pain can be better controlled by the self-administration of small, repetitive, on-demand, intravenous doses of narcotics using a PCA infuser than by the traditional timed intramuscular administration of these drugs (4-6). It has been also reported that midazolam can be given using a PCA infuser to provide anxiolysis in the intensive care unit (7). A logical extension of this form of analgesia or anxiolysis is to allow patients to find and maintain their own steady state of sedation by self-administration of sedatives and/or narcotics during surgery. This study was designed to evaluate the feasibility and advantages or disadvantages, if any, of patient-controlled sedation (PCS) compared with sedation provided by an anesthesiologist during surgery performed under epidural anesthesia.
Methods Supported in part by Abbott Laboratories. Received from the V.A. Medical Center and the Department of Anesthesiology, Georgetown University Medical School, Washington, D.C. Accepted for publication October 16, 1990. Address correspondence to Dr. Park, Chief of Anesthesiology, V.A. Medical Center, 50 Irving Street N.W., Washington, DC 20422. 01991 by the International Anesthesia Research Society 0003-2999/91/$3.50
Forty patients scheduled to have epidural anesthesia for proposed elective surgery of lower extremities or lower abdomen and who had no history of narcotic abuse were investigated. Patients were divided equally into two groups at random with 20 patients in
PATIENT-CONTROLLED SEDATION
each group. For sedation during anesthesia and surgery, patients in group 1 were given midazolam and fentanyl administered intravenously in divided doses at the discretion of the anesthesiologist. Patients in group 2 self-administered a mixture of midazolam and fentanyl intravenously using a PCA infuser. Permission to conduct this study was obtained from the hospital’s research review committee. After obtaining informed consent, patients were premedicated with 5-10 mg diazepam and/or 5-10 mg morphine. Morphine was administered intramuscularly and diazepam was administered either orally or intramuscularly approximately 1 h before surgery. On arrival in the operating room, the degree of sedation from premedication was rated jointly by the anesthesiologist assigned to the case and by the investigator using the ”Sedation Scale’’ (1-10, 1 = fully awake; 5 = moderate sedation: resting comfortably with eyes closed but responsive to verbal stimuli; 10 = heavy sedation: unresponsive to verbal stimuli but responsive to gentle tactile stimuli). An intravenous cannula was inserted and a blood pressure cuff, electrocardiogram electrodes, and a pulse-oxymetry probe were applied. If indicated, the anesthesiologist administered 0.5-1.0 mg midazolam and/or 25-50 pg fentanyl in increments intravenously in group 1 patients before performing the epidural block. Midazolam was administered for sedation, and fentanyl was used to treat pain (or discomfort). Patients in group 2, on the other hand, self-administered a mixture of midazolam and fentanyl in 2.5-mL increments (each milliliter containing 0.2 mg midazolam and 10 pg fentanyl) as desired using an Abbott Lifecare PCA infuser (Abbott Laboratories, North Chicago, Ill.). The PCA infuser was programmed to allow self-administration of 2.5 mL of the mixture of midazolam and fentanyl with a minimum of a 5-min obligatory lock-out interval between consecutive doses. When the patient was adequately sedated, he or she was placed in the lateral decubitus position on a horizontal operating room table. A #17 Tuohy needle was introduced through the second or third lumbar intervertebral space, and the epidural space was identified using ”loss of resistance” technique. With the bevel of the needle pointing cephalad, 3 mL of 1.5%-2.0% lidocaine or 0.5% bupivacaine, both with epinephrine (1:200,000), was injected. After 1 min, if there was no evidence of inadvertent subarachnoid or intravenous injection of the drug, an additional amount of the same local anesthetic was injected at the approximate rate of 1.0 mL/s. An epidural catheter was inserted if indicated, and the patient was then positioned for surgery. Oxygen (3 L/min) was administered by nasal cannula in the operating room.
ANESTH ANALG 1991;72:304-7
305
Table 1. Demographics of the Study Patients
Age (Yd Height (cm) Weight (kg)
Group 1 (n = 20)
Group 2 (n = 20)
P
59.6 2 16.7 175.6 & 8.1 78.5 2 14.8
56.3 k 10.4 172.5 2 7.9 79.8 k 13.9
NS NS NS
Values are expressed as mean 2 SD. Group I, anesthesiologist-controlled sedation; group 2, patientcontrolled sedation; NS, not significant.
Skin incision was made only after confirming the presence of an adequate level and intensity of epidural anesthesia for the proposed surgery. During the surgery, patients in group 1 had midazolam administered intravenously in increments for sedation and fentanyl to treat discomfort (or pain) as determined by the anesthesiologist. Patients in group 2 selfadministered a mixture of midazolam and fentanyl using a preprogrammed Abbott PCA infuser. At the end of surgery the total doses of midazolam and fentanyl given were calculated and the overall adequacy of the sedation during surgery was rated jointly by the anesthesiologist assigned to the case and the investigator using the aforementioned sedation scale. The patient was observed for any of the following complications during the study: (a) respiratory rate
