Usefulness of epidural administration of ketamine for relief of postherpetic neuralgia

Four patients with postherpetic neuralgia had their pain alleviated by epidural administration of ketamine. No oral non-steroidal anti-inflammatory drugs and anti-depressant drugs were effective in all cases. Lidocaine or bupivacaine was administered epidurally to all four patients. When these patients stated that they did not feel pain reduced, they received epidural infusion of ketamine at doses from 5 mg to 20 mg with lidocaine or bupivacaine and their postherpetic neuralgia was controlled. Therefore with these cases, we suspect that epidural administration of ketamine, an antagonist for N-methyl-D-aspartic acid receptor, could be an effective and useful alternative treatment in a patient with refractory postherpetic neuralgia.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.     

Differential Effect of Ketamine and Lidocaine on Spontaneous and Mechanical Evoked Pain in Patients with Nerve Injury Pain

Background: The mechanisms underlying neuropathic pain are incompletely understood. Targeting specific molecular mechanisms in the pain signaling system may assist in understanding key features in neuropathic pains such as allodynia. This study examined the effect of systemically administered ketamine, an N-methyl-d-aspartate receptor antagonist and lidocaine, a sodium channel blocker, on spontaneous pain, brush-evoked pain, and pinprick-evoked pain in patients with nerve injury pain.

Methods: Twenty patients participated in two randomized, double-blinded, placebo-controlled, crossover experiments in which they, on four different days, received a 30-minute intravenous infusion of ketamine (0.24 mg/kg), lidocaine (5 mg/kg), or saline. Ongoing pain, pain evoked by brush and repetitive pinprick stimuli, and acetone was measured before, during, and after infusion.

Results: Ketamine significantly reduced ongoing pain and evoked pain to brush and pinprick, whereas lidocaine only reduced evoked pain to repetitive pinprick stimuli. In individual patients, there was no correlation between the pain-relieving effect of lidocaine and ketamine on ongoing or mechanically evoked pains.     

Usefulness of epidural infusion of ketamine for relief of localized superficial pain]

Three patients with localized superficial pain had their pain alleviated by single epidural infusion with low dose ketamine. The patients are as follows: a 62-year-old female with herpetic neuralgia on her right sixth thoracic nerve area; a 52-year-old male whose left shoulder, anterior chest and abdomen had been burned by acetylene gas; and a 49-year-old male whose bilateral hands suffering from frostbite by propane gas. Epidural tube insertion to administer a single dose of 10 mg ketamine with lidocaine or bupibacaine was performed in all the three patients. They were administered single epidural infusion of 10 mg ketamine with lidocaine or bupibacaine everyday and they continued to receive epidural block with lidocaine or bupivacaine including buprenorphine or morphine. Therefore, we suspect that single epidural infusion of ketamine, an antagonist for N-methyl-D-aspartic acid receptor, could be an effective and useful alternative treatment in patients with various refractory localized superficial pain of either acute or chronic nature.     

Oral ketamine and transdermal nitroglycerin as analgesic adjuvants to oral morphine therapy for cancer pain management.

BACKGROUND: Guidelines for cancer pain management include nonsteroidal antiinflammatory drugs with opioids administered in a time-contingent manner. This study was designed to evaluate the role of oral ketamine or transdermal nitroglycerin polymer, a nitric oxide donor, as coadjuvants to oral morphine in cancer pain therapy. METHODS: After institutional approval and informed patient consent were obtained, 60 patients with cancer pain were randomized to one of four groups (n = 15) and studied prospectively to evaluate analgesia and any adverse effects. A visual analog scale that consisted of a 10-cm line with 0 representing "no pain at all" and 10 representing "the worst possible pain" was introduced. All patients were regularly taking oral amitriptyline 50 mg at bedtime. The morphine regimen was adjusted individually to a maximal oral dose of 80-90 mg/day to keep the visual analog scale score less than 4. When patients reported pain (visual analog scale of 4 or more), despite taking 80-90 mg oral morphine daily, the test drug was added as follows: the control group (CG) received an additional 20 mg oral morphine (10 mg at 12-h intervals); the nitroglycerin group (NG) received a 5-mg nitroglycerin patch daily; the ketamine group (KG) received 0.5 mg/kg oral ketamine at 12-h intervals; and the dipyrone group (DG) received 500 mg oral dipyrone at 6-h intervals. Patients were free to manipulate their daily morphine consumption when the test drug was introduced to keep their visual analog scale score less than 4. RESULTS: The groups were similar with respect to demographic data and visual analog scale pain scores before treatment. The visual analog scale scores after the test drug was introduced were similar among the groups. The daily consumption of oral morphine was as follows: on day 15: CG = DG = NG (P > 0.05), CG > KG (P = 0.036); on day 20: CG > NG = KG (P < 0.02) (CG > KG, P < 0.005; CG > NG, P < 0.02), DG > KG (P < 0.05); on day 30: CG = DG > KG = NG (P < 0.05). Patients in the CG and DG groups reported somnolence, but patients in the NG and KG groups did not. CONCLUSIONS: Low-dose ketamine and transdermal nitroglycerin were effective coadjuvant analgesics. In conjunction with their opioid tolerance-sparing function, joint delivery of ketamine or nitric oxide donors with opiates may be of significant benefit in cancer pain management.     

Effect of systemic N-methyl-D-aspartate receptor antagonist (ketamine) on primary and secondary hyperalgesia in humans

Ketamine reduces nociception by binding noncompetitively to the N- methyl-D-aspartate (NMDA) receptor, activation of which increases spinal hypersensitivity. We studied 19 healthy, unmedicated male volunteers, aged 20-31 yr. Burn injuries were produced on the medial surface of the dominant calf with a 25 x 50 mm rectangular thermode. On 3 separate days, at least 1 week apart, subjects received a bolus of either ketamine 0.15 mg kg-1, ketamine 0.30 mg kg-1 or placebo, delivered by a mechanical infusion pump over 15 min. The bolus was followed by continuous infusion of ketamine 0.15 mg kg-1 h-1, ketamine 0.30 mg kg-1 h-1 or placebo, respectively, for 135 min. Ketamine reduced the magnitude of both primary and secondary hyperalgesia, and also pain evoked by prolonged noxious heat stimulation, in a dose- dependent manner. In contrast, ketamine did not alter phasic heat pain perception (perception of transient, painful, thermal stimuli) in undamaged skin. The analgesic effects of ketamine in the burn injury model are in agreement with results from experimental studies, and can be distinguished from those of local anaesthetics and opioids. Side effects caused by continuous infusion of ketamine 0.15 and 0.30 mg kg-1 h-1 were frequent but clinically acceptable.      

Low-dose intravenous ketamine potentiates epidural analgesia after thoracotomy

BACKGROUND: Ketamine potentiates intravenous or epidural morphine analgesia. The authors hypothesized that very-low-dose ketamine infusion reduces acute and long-term postthoracotomy pain. METHODS: Forty-nine patients scheduled to undergo open thoracotomy were randomly assigned to receive one of two anesthesia regimens: continuous epidural infusion of ropivacaine and morphine, along with intravenous infusion of ketamine (0.05 mg . kg(-1) . h(-1) [approximately 3 mg/h], ketamine group, n = 24) or placebo (saline, control group, n = 25). Epidural analgesia was continued for 2 days after surgery, and infusion of ketamine or placebo was continued for 3 days. Pain was assessed at 6, 12, 24, and 48 h after surgery. Patients were asked about their pain, abnormal sensation on the wound, and inconvenience in daily life at 7 days and 1, 3, and 6 months after surgery. RESULTS: The visual analog scale scores for pain at rest and on coughing 24 and 48 h after thoracotomy were lower in the ketamine group than in the control group (pain at rest, 9 +/- 11 vs. 25 +/- 20 and 9 +/- 11 vs. 18 +/- 13; pain on coughing, 26 +/- 16 vs. 50 +/- 17 and 30 +/- 18 vs. 43 +/- 18, mean +/- SD; P = 0.002 and P = 0.01, P < 0.0001 and P = 0.02, respectively). The numerical rating scale scores for baseline pain 1 and 3 months after thoracotomy were significantly lower in the ketamine group (0.5 [0-4] vs. 2 [0-5] and 0 [0-5] vs. 1.5 [0-6], median [range], respectively; P = 0.02). Three months after surgery, a higher number of control patients were taking pain medication (2 vs. 9; P = 0.03). CONCLUSIONS: Very-low-dose ketamine (0.05 mg . kg(-1) . h(-1)) potentiated morphine-ropivacaine analgesia and reduced postthoracotomy pain.     

Differential effect of ketamine and lidocaine on spontaneous and mechanical evoked pain in patients with nerve injury pain

BACKGROUND: The mechanisms underlying neuropathic pain are incompletely understood. Targeting specific molecular mechanisms in the pain signaling system may assist in understanding key features in neuropathic pains such as allodynia. This study examined the effect of systemically administered ketamine, an N-methyl-D-aspartate receptor antagonist and lidocaine, a sodium channel blocker, on spontaneous pain, brush-evoked pain, and pinprick-evoked pain in patients with nerve injury pain. METHODS: Twenty patients participated in two randomized, double-blinded, placebo-controlled, crossover experiments in which they, on four different days, received a 30-minute intravenous infusion of ketamine (0.24 mg/kg), lidocaine (5 mg/kg), or saline. Ongoing pain, pain evoked by brush and repetitive pinprick stimuli, and acetone was measured before, during, and after infusion. RESULTS: Ketamine significantly reduced ongoing pain and evoked pain to brush and pinprick, whereas lidocaine only reduced evoked pain to repetitive pinprick stimuli. In individual patients, there was no correlation between the pain-relieving effect of lidocaine and ketamine on ongoing or mechanically evoked pains. CONCLUSIONS: N-methyl-D-aspartate receptor-linked systems and sodium channels are involved in generation and maintenance of pain in patients with peripheral nerve injury. It is likely that ongoing pain as well as mechanical hyperalgesia in individual patients is dependent on several separate molecular mechanisms.     

Intra-operative ketamine administration reduced the level of post-thoracotomy pain

BACKGROUND: Two different types of post-operative pain (such as acute pain and chronic pain) occur in patients undergoing thoracotomy. It has been suggested that the acute post-thoracotomy pain consists of inflammatory pain and chronic post-thoracotomy pain caused by intercostal neuralgia. In the present study, we examined the effect of intra-operative administration of ketamine, an NMDA receptor antagonist, on the acute and chronic post-thoracotomy pain. METHODS: Sixteen patients were assigned to one of two groups (ketamine or control). The ketamine group received a ketamine bolus (1 mg x kg(-1)) just before the skin incision, followed by continuous infusion of ketamine (1 mg x kg(-1) x hr(-1)) during surgery. RESULTS: Verbal rating scores (VRSs) at rest and on cough were significantly lower in the ketamine group on day 1 and VRS of chronic pain was also significantly lower in the ketamine group 4 weeks after the surgery. CONCLUSIONS: These data suggest that post-thoracotomy pain might be mediated by NMDA receptor dependent central sensitization and that the intra-operative administration of ketamine might block the development of the NMDA receptor dependent central sensitization.     

Low-dose Intravenous Ketamine Potentiates Epidural Analgesia after Thoracotomy

Background: Ketamine potentiates intravenous or epidural morphine analgesia. The authors hypothesized that very-low-dose ketamine infusion reduces acute and long-term postthoracotomy pain.

Methods: Forty-nine patients scheduled to undergo open thoracotomy were randomly assigned to receive one of two anesthesia regimens: continuous epidural infusion of ropivacaine and morphine, along with intravenous infusion of ketamine (0.05 mg [middle dot] kg-1 [middle dot] h-1 [approximately 3 mg/h], ketamine group, n = 24) or placebo (saline, control group, n = 25). Epidural analgesia was continued for 2 days after surgery, and infusion of ketamine or placebo was continued for 3 days. Pain was assessed at 6, 12, 24, and 48 h after surgery. Patients were asked about their pain, abnormal sensation on the wound, and inconvenience in daily life at 7 days and 1, 3, and 6 months after surgery.

Results: The visual analog scale scores for pain at rest and on coughing 24 and 48 h after thoracotomy were lower in the ketamine group than in the control group (pain at rest, 9 +/- 11 vs. 25 +/- 20 and 9 +/- 11 vs. 18 +/- 13; pain on coughing, 26 +/- 16 vs. 50 +/- 17 and 30 +/- 18 vs. 43 +/- 18, mean +/- SD; P = 0.002 and P = 0.01, P < 0.0001 and P = 0.02, respectively). The numerical rating scale scores for baseline pain 1 and 3 months after thoracotomy were significantly lower in the ketamine group (0.5 [0-4] vs. 2 [0-5] and 0 [0-5] vs. 1.5 [0-6], median [range], respectively; P = 0.02). Three months after surgery, a higher number of control patients were taking pain medication (2 vs. 9; P = 0.03).     

Postoperative pain management using subcutaneous fentanyl and ketamine after abdominal gynecologic surgery

BACKGROUND: Subcutaneous opioid is one way of managing postoperative pain in patients undergoing anticoagulant therapy. We have evaluated the safety and the efficacy of postoperative pain management using subcutaneous fentanyl and ketamine after abdominal gynecologic surgery. METHODS: Written informed consent was obtained from 50 ASA physical status 1 or 2 female patients aged between 20 and 65. Patients were randomized to one of 5 groups. Group 1, 2 and 3 received 25, 35 and 50 microg x h(-1) subcutaneous fentanyl infusion, respectively. Group 4 received 25 microg x h(-1) fentanyl and 2 mg x h(-1) ketamine subcutaneously; group 5 received 25 microg x h(-1) fentanyl and 4 mg x h(-1) ketamine subcutaneously. General anesthesia was administered to all patients. Two hours after induction, subcutaneous infusion of fentanyl and ketamine was started in the patients and discontinued 24 hours after the operation. All patients were assessed twice, at 4 hours and at 24 hours after operation. Blood gas analysis was performed. Number of analgesic administration required during the 24 hours after operation was recorded. Groups 1, 2, 3 and groups 1, 4, 5 were evaluated as one group, respectively. Group differences were analyzed by variance analysis. Differences of analgesic administration were analyzed with Kruskal-Wallis test. RESULTS: As to anesthetic requirement during the 24 hours after operation, there were no significant differences among treatment groups. With respect to blood gas analysis, only individuals receiving subcutaneous 25 microg x h(-1) fentanyl and 4 mg x h(-1) ketamine maintained high PaO2 4 hours after the operation (P<0.05). CONCLUSIONS: We recommend administration of 25 microg x h(-1) fentanyl and 4 mg x h(-1) ketamine subcutaneously, which maintains high Pao2 and requires less analgesic.     

The use of ketamine for abdominal tubal ligation

A study was made of ketamine hydrochloride's effectiveness in decreasing viseral pain in 50 patients undergoing postpartum abdominal tubal ligation, a procedure involving visceral pain but not requiring muscular relaxation. Patients were pre-medicated and ketamine was administered (10 mg/ml intravenously) until the patient no longer responded to surgical stimulae. The majority of patients (39) required 1 mg/kg of ketamine for induction and repeated doses of 20 mg each, every 5 minutes, for maintenance (31 patients). Analgesic effectiveness was judged on the following basis: Good - no movement or phonation during surgery (74 percent); Fair - slight limb movement or occasional phonation (20 percent); Poor - gross movement or loud phonation (6 percent). On the average blood pressure rose 14 percent, heart rate 21 percent, and respiratory rate 34 percent. Some dizziness was experienced by all patients. Alveolar-arterial oxygen difference was increased in several cases; possibly due to increase in right-to-left pulmonary blood shunt. Ketamine was found to be an adequate anaesthetic in 94% of patients with administered doses well below recommended amounts.     

Use of propofol for painful procedures in cancer pain management

BACKGROUND: Patients with intractable cancer pain often require non-pharmacological analgesic treatment that is accompanied by procedure-related pain. Previous works have shown that propofol infusion in adjunction to regional anesthesia provides appropriate sedation during such painful procedures. However, there are a few reports of its use to reduce procedure-related pain in terminal cancer patients. We report cases of propofol sedation during percutaneous vertebroplasty (PVP) in patients with metastatic vertebral compression fracture. METHODS: Propofol was infused during PVP in eleven cancer patients after obtaining written informed consent. The infusion rate of propofol was adjusted using a target-controlled infusion pump to achieve appropriate sedation levels under monitoring bispectral index of the electroencepharogram. Hepatic and renal functions were evaluated using common serum markers, which were determined using standard hospital laboratory methods. RESULTS: The duration of the procedure was 65.5 +/- 5.5 (mean +/- SD) min. The required infusion rate was 8.66 +/- 1.50 mg.kg-1.hr-1. The interval from the termination of the infusion until emergence was 10.7 +/- 4.2 min. No life-threatening complications or significant changes in liver and renal functions were observed. CONCLUSIONS: Propofol can be used effectively and safely for sedation during PVP in terminal cancer patients.     

Effect of i.v. ketamine in combination with epidural bupivacaine or epidural morphine on postoperative pain and wound tenderness after renal surgery

We studied 60 patients undergoing operation on the kidney with combined general and epidural anaesthesia, in a double-blind, randomized, controlled study. Patients were allocated to receive a preoperative bolus dose of ketamine 10 mg i.v., followed by an i.v. infusion of ketamine 10 mg h-1 for 48 h after operation, or placebo. During the first 24 h after surgery, all patients received 4 ml h-1 of epidural bupivacaine 2.5 mg ml-1. From 24 to 48 h after operation, patients received epidural morphine 0.2 mg h-1 preceded by a bolus dose of 2 mg. In addition, patient-controlled analgesia (PCA) with i.v. morphine (2.5 mg, lockout time 15 min) was offered from 0 to 48 h after operation. Patients who received ketamine felt significantly more sedated at 0-24 h, but not at 24-48 h after operation, compared with patients who received placebo (P = 0.002 and P = 0.127, respectively). There were no significant differences in pain (VAS) at rest, during mobilization or cough, PCA morphine consumption, sensory block to pinprick, pressure pain detection threshold assessed with an algometer, touch and pain detection thresholds assessed with von Frey hairs, peak flow or side effects other than sedation. The power of detecting a reduction in VAS scores of 20 mm in our study was 80% at the 5% significance level. We conclude that we were unable to demonstrate an (additive) analgesic or opioid sparing effect of ketamine 10 mg h-1 i.v. combined with epidural bupivacaine at 0-24 h, or epidural morphine at 24-48 h after renal surgery.      

Anesthetic management of an emergency surgery for panperitonitis during an asthmatic attack

We report anesthetic management of an emergency surgery for panperitonitis during an asthmatic attack in a patient with angina pectoris. A 71-year-old male patient, complaining of abdominal pain and dyspnea, was diagnosed as having panperitonitis and asthmatic attack by surgeons in the emergency room. General anesthesia was induced by intravenous injection of propofol (30 mg), ketamine (30 mg), fentanyl (200 micrograms), suxamethonium (60 mg) and diltiazem (5 mg) following cannulation of the left radial artery for continuous monitoring of direct arterial pressure. Anesthesia was maintained by continuous infusion of propofol (4-10 mg.kg-1.h-1) and ketamine (1 mg.kg-1.h-1) in combination with intermittent epidural injection of local anesthetics. Although sudden onset of increased peak airway pressure occurred 45 minutes after starting operation, 50 mg of propofol injection and 500 mg of aminophyline infusion could relieve this high airway pressure. Because increased peak airway pressure appeared frequently and this could not be relieved by bolus injection of propofol, we changed the intravenous anesthesia to nitrous oxide-oxygen-isoflurane (GOI). After this change, no asthmatic attack occurred during the operation. While the mechanical ventilation was required during the early postoperative period along with infusion of aminophyline and inhalation of beta-stimulants, the patient was weaned successfully from the mechanical ventilation 12 hours postoperatively. It was speculated that the intraoperative asthmatic attack might have been caused by light level of anesthesia with propofol and ketamine. We concluded that other analgesics, such as fentanyl or epidural local anesthetics, must have been supplemented at proper timing during the continuous infusion of propofol and ketamine during the surgery.     

Low doses of epidural ketamine or neostigmine, but not midazolam, improve morphine analgesia in epidural terminal cancer pain therapy

Study Objective: To examine analgesia and adverse effects of combination epidural pain therapy consisting of administration of morphine with either low dose of ketamine, neostigmine, or midazolam in terminal cancer pain patients.

Design: Randomized double-blind study.

Setting: Teaching hospital.

Patients: 48 terminal cancer patients suffering from chronic pain.

Interventions: Patients were randomized to one of four groups (n = 12). The concept of visual analog scale (VAS), which consisted of a 10-cm line with 0 equaling “no pain at all” and 10 equaling “the worst possible pain” was introduced. All patients were taking oral amitriptyline 50 mg at bedtime. Pain was initially treated with epidural morphine 2 mg twice daily (12-hr intervals) to maintain the VAS below 4/10. Afterwards, VAS scores ≥4/10 at any time were treated by adding the epidural study drug (2 ml), which was administered each morning, just after the 2-mg epidural morphine administration. The control group (CG) received 2 mg of epidural morphine (2 ml). The ketamine group (KG) received 0.2 mg/kg epidural ketamine (2 ml). The neostigmine group (NG) received 100 μg epidural neostigmine (2 ml). The midazolam group (MG) received 500 μg epidural midazolam (2 ml). Patients received the study drugs on a daily basis.

Measurements and Main Results: Duration of effective analgesia was measured as time from the study drug administration to the first patient’s VAS score ≥4/10 recorded in days. The groups were demographically the same. The VAS pain scores prior to the treatment were also similar among groups. Only the patients in the KG demonstrated lower VAS scores compared to the MG (p = 0.018). Time since the epidural study drug administration until patient complaint of pain VAS ≥4/10 was higher for both the KG and NG compared to the CG (KG > CG, p = 0.049; NG > CG; p = 0.0163). Only the KG used less epidural morphine compared to the CG during the period of study (25 days) (p = 0.003).

Conclusion: The association of either low-dose epidural ketamine or neostigmine (but not midazolam) to epidural morphine increased the duration of analgesia in the population studied (gt;20 days) compared to the CG and MG (8 to 10 days) when administered in the early stages of terminal cancer pain therapy, without increasing the incidence of adverse effects.     

Oral Ketamine and Transdermal Nitroglycerin as Analgesic Adjuvants to Oral Morphine Therapy for Cancer Pain Management

Background: Guidelines for cancer pain management include nonsteroidal antiinflammatory drugs with opioids administered in a time-contingent manner. This study was designed to evaluate the role of oral ketamine or transdermal nitroglycerin polymer, a nitric oxide donor, as coadjuvants to oral morphine in cancer pain therapy.

Methods: After institutional approval and informed patient consent were obtained, 60 patients with cancer pain were randomized to one of four groups (n = 15) and studied prospectively to evaluate analgesia and any adverse effects. A visual analog scale that consisted of a 10-cm line with 0 representing "no pain at all" and 10 representing "the worst possible pain" was introduced. All patients were regularly taking oral amitriptyline 50 mg at bedtime. The morphine regimen was adjusted individually to a maximal oral dose of 80-90 mg/day to keep the visual analog scale score less than 4. When patients reported pain (visual analog scale of 4 or more), despite taking 80-90 mg oral morphine daily, the test drug was added as follows: the control group (CG) received an additional 20 mg oral morphine (10 mg at 12-h intervals); the nitroglycerin group (NG) received a 5-mg nitroglycerin patch daily; the ketamine group (KG) received 0.5 mg/kg oral ketamine at 12-h intervals; and the dipyrone group (DG) received 500 mg oral dipyrone at 6-h intervals. Patients were free to manipulate their daily morphine consumption when the test drug was introduced to keep their visual analog scale score less than 4.

Results: The groups were similar with respect to demographic data and visual analog scale pain scores before treatment. The visual analog scale scores after the test drug was introduced were similar among the groups. The daily consumption of oral morphine was as follows: on day 15: CG = DG = NG (P > 0.05), CG > KG (P = 0.036); on day 20: CG > NG = KG (P < 0.02) (CG > KG, P < 0.005; CG > NG, P < 0.02), DG > KG (P < 0.05); on day 30: CG = DG > KG = NG (P < 0.05). Patients in the CG and DG groups reported somnolence, but patients in the NG and KG groups did not.     

Total intravenous anesthesia for two patients complicated with myotonic dystrophy

Total intravenous anesthesia with propofol, fentanyl and ketamine (PFK) was given to two patients complicated with myotonic dystrophy. Case-1: A 42-year-old female underwent a hemithyroidectomy. Anesthesia was induced slowly with intravenous ketamine 20 mg and propofol 60 mg. Her tracheal intubation was performed smoothly without any muscle relaxants. Anesthesia was maintained with propofol infusion of 5 mg.kg-1.h-1, ketamine infusion of 0.3 mg.kg-1.h-1 and fentanyl 200 micrograms in total. She regained consciousness 20 minutes after the end of propofol infusion, and 15 minutes later, her trachea was extubated without any troubles. Case-2: A 41-year-old female underwent a removal of left parotid tumor. Anesthesia was induced slowly with ketamine 40 mg and propofol 100 mg intravenously. Anesthesia was maintained with propofol infusion of 5-10 mg.kg-1.h-1, ketamine infusion of 0.5 mg.kg-1.h-1 and fentanyl 350 micrograms in total. No muscle relaxant was used through the surgical procedure. Emergence from anesthesia was observed 10 minutes after the end of propofol infusion and her trachea was extubated. When a nasogastric tube was pulled out, her respiration stopped suddenly and she was intubated again only for two hours without any troubles. In both cases their serum CPK levels and rectal temperatures were very stable. PFK method would be a choice for patients with myotonic dystrophy.     

Low-dose ketamine infusion for analgesia during postoperative ventilator treatment

In a randomized, double-blind study with placebo, ketamine was used as an analgesic during ventilator treatment in the period of recovery after major abdominal surgery. Forty patients were orally intubated and ventilated by means of a volume-controlled ventilator. Twenty of them received an i.v. bolus of 30 mg of ketamine followed by an 8-h infusion of 1 mg per minute. End-tidal CO2-concentration was continuously monitored and ventilation was adjusted to metabolic demands prior to assessment of pain. If pain relief was not adequate, the infusion rate was doubled, and if this was still not sufficient, 5 mg injections of ketobemidone were given i.v. If the orotracheal tube was not tolerated, the internal branch of the superior laryngeal nerve was blocked. A total of 30 injections of ketobemidone were administered to 13 control patients, but only five were given to four ketamine patients. Ten control and three ketamine patients required an internal laryngeal nerve block. Dreams and hallucinations were recalled in three patients in the control group and five in the ketamine group. Only one control and two ketamine patients experienced these as unpleasant. In this investigation, ketamine infusion in a low dose appeared to offer satisfactory analgesia and to permit tolerance of the orotracheal tube.     

Effect of Vecuronium and Pancuronium on Cardiac Performance and Transmural Myocardial Perfusion During Ketamine Anaesthesia

The haemodynamic effects of vecuronium and pancuronium were studied in 20 healthy patients during diazepam/ketamine anaesthesia. Anaesthesia was induced with glycopyrrolate 3 micrograms/kg, diazepam 0.3 mg/kg and ketamine 1.0 mg/kg as a bolus and 1.0 mg/kg over 10 min. After induction, anaesthesia was maintained with ketamine infusion 1.0 mg/kg/h. The lungs were ventilated with 50% nitrous oxide in oxygen. Equipotent doses of vecuronium (74 micrograms/kg) or pancuronium (99 micrograms/kg) were administered for intubation. The thoracic impedance, ECG and phonocardiogram were recorded during the induction of anaesthesia. The results suggest that vecuronium has no cardiovascular effects during ketamine anaesthesia, whereas pancuronium due to its chronotropic effect, causes a deterioration in left ventricular performance.