Richard A. Steinbrook

Ketamine as Adjuvant Analgesic to Opioids: A Quantitative and Qualitative Systematic Review

Animal studies on ketamine and opioid tolerance have shown promising results. Clinical trials have been contradictory. We performed a systematic review of randomized, double-blind clinical trials of ketamine added to opioid analgesia. Thirty-seven trials with 51 treatment arms and 2385 patients were included. Studies were divided into 5 subgroups: IV ketamine as single dose (n = 11), continuous infusion (n = 11), patient-controlled analgesia (PCA) (n = 6), epidural ketamine with opioids (n = 8), and studies in children (n = 4). Outcome measures included pain scores, time to first request for analgesia, supplemental analgesics, and adverse events. Efficacy was estimated by statistical significance (P <0.05) of outcome measures as reported in studies and also by calculation of weighted mean difference for pain scores during the first 24 h after surgery. As compared to morphine alone, IV PCA with ketamine and morphine did not improve analgesia. Intravenous infusion of ketamine decreased IV and epidural opioid requirements in 6 of 11 studies. A single bolus dose of ketamine decreased opioid requirements in 7 of 11 studies. Five of 8 trials with epidural ketamine showed beneficial effects. Adverse effects were not increased with small dose ketamine. We conclude that small dose ketamine is a safe and useful adjuvant to standard practice opioid-analgesia.

Epidural anesthesia and gastrointestinal motility.

P ostoperative ileus, a temporary inhibition of gastrointestinal function, is a universal complication after major abdominal surgery. Treatment for ileus is supportive and has changed little since Wangensteen’s 1932 report (1) that nasogastric suction could delay or replace operative management of bowel obstruction, thereby reducing mortality. Gastric decompression, together with IV hydration and electrolyte replacement, remains the only proven therapy for ileus (2,3). Liu et al. (4) suggest that epidural analgesia may significantly shorten the duration of postoperative ileus. The benefits of a reduction in ileus include decreased patient morbidity and potentially substantial cost-savings, as prolongation of hospitalization in the United States due to ileus has been estimated to cost

Continuous noninvasive monitoring of cardiac output with esophageal Doppler ultrasound during cardiac surgery.

1,500 per patient or

Arterial to End-tidal Carbon Dioxide Pressure Difference during Laparoscopic Surgery in Pregnancy

750,000,000 annually (3). Nevertheless, clinical guidelines currently promulgated by some consulting firms continue to state that “while epidural analgesia is effective for thoracic surgery and certain major musculoskeletal procedures, it has often been associated with prolonged ileus, delayed oral nutrition, and discharge in patients with gastrointestinal surgery” (Milliman and Robertson, Inc, Actuaries and Consultants, Seattle, WA, written communication, 1996). In this article, the pathophysiology of postoperative ileus is reviewed, and a framework for appreciating the theoretical basis for an effect of epidural anesthesia, especially thoracic epidural anesthesia, on ileus is provided. Potential risks and benefits of epidural anesthesia for bowel surgery are considered, including an examination of relevant animal studies. The major focus of this article is to review recent clinical studies comparing epidural analgesia with systemic analgesia, as well as to review studies comparing epidural narcotics with epidural local anesthetics with regard to postoperative ileus. Catheter location is discussed as a particularly important factor in determining the effects of epidural blockade on gastrointestinal motility. Finally, suggestions for future research are offered.

Prophylactic antiemetics for laparoscopic cholecystectomy : Ondansetron versus droperidol plus metoclopramide

Esophageal Doppler ultrasonography offers a continuous and noninvasive alternative to standard thermodilution cardiac output monitoring. A total of 372 simultaneous measurements of Doppler and thermodilution cardiac output were compared in 16 patients undergoing cardiac surgery. In addition, echocardiographic aortic diameter measurement, necessary for Doppler calibration, was compared with direct surgical measurement in 23 patients. Echocardiographic aortic measurement was often time consuming and correlated poorly (r = 0.31) with surgical measurement. On the other hand, Doppler cardiac output was determined easily and accurately tracked thermodilution cardiac output (R2 = 0.95, common slope coefficient 1.050, by multiple linear regression). Furthermore, Doppler cardiac output was more reproducible, showing less short-term variability than thermodilution cardiac output. The esophageal Doppler technique allows cardiac output monitoring in patients for whom invasive monitoring is not warranted.

Laparoscopic cholecystectomy during pregnancy

Background There is controversy about whether capnography is adequate to monitor pulmonary ventilation to reduce the risk of significant respiratory acidosis in pregnant patients undergoing laparoscopic surgery. In this prospective study, changes in arterial to end-tidal carbon dioxide pressure difference (PaCO2–-PetCO2), induced by carbon dioxide pneumoperitoneum, were determined in pregnant patients undergoing laparoscopic cholecystectomy. Methods Eight pregnant women underwent general anesthesia at 17–30 weeks of gestation. Carbon dioxide pnueumoperitoneum was initiated after obtaining arterial blood for gas analysis. Pulmonary ventilation was adjusted to maintain PetCO2 around 32 mmHg during the procedure. Arterial blood gas analysis was performed during insufflation, after the termination of insufflation, after extubation, and in the postoperative period. Results The mean ± SD for PaCO2–-PetCO2 was 2.4 ± 1.5 before carbon dioxide pneumoperitoneum, 2.6 ± 1.2 during, and 1.9 ± 1.4 mmHg after termination of pneumoperitoneum. PaCO2 and p H during pneumoperitoneum were 35 ± 1.7 mmHg and 7.41 ± 0.02, respectively. There were no significant differences in either mean PaCO2–-PetCO2 or PaCO2 and p H during various phases of laparoscopy. Conclusions Capnography is adequate to guide ventilation during laparoscopic surgery in pregnant patients. Respiratory acidosis did not occur when PetCO2 was maintained at 32 mmHg during carbon dioxide pneumoperitoneum.

Dissociation of plasma and cerebrospinal fluid beta-endorphin-like immunoactivity levels during pregnancy and parturition.

Two hundred adults undergoing laparoscopic cholecystectomy were enrolled in a prospectively randomized, double-blind investigation comparing ondansetron, 4 mg (Group O) with the combination of droperidol, 0.625 mg, and metoclopramide, 10 mg (Group DM). Antiemetic drugs were administered intravenously (IV) after induction of general anesthesia (propofol, desflurane). Moderate or severe nausea in the postanesthesia care unit was treated with the crossover drug, i.e., ondansetron for patients in Group DM or droperidol plus metoclopramide for patients in Group O. Data were analyzed using t-tests and chi squared analyses, with P < 0.05 considered statistically significant. The groups were similar with respect to gender, age, weight, duration of surgery, number receiving intraoperative atropine or ephedrine, number admitted overnight, and time to discharge home. Of 102 patients in Group O, 44 required antiemetics in the postanesthesia care unit, compared with 24 of 98 patients in Group DM (P < 0.01). One patient (in Group DM) was admitted for persistent nausea. In conclusion, droperidol 0.625 mg IV in combination with metoclopramide 10 mg IV was more effective in preventing postoperative nausea than was ondansetron 4 mg IV in patients undergoing laparoscopic cholecystectomy, with no difference in the time to discharge. (Anesth Analg 1996;83:1081-3)

Effects of Alkalinization of Lidocaine on the Pain of Skin Infiltration and Intravenous Catheterization

AbstractBackground: We present our experience with laparoscopic cholecystectomy in pregnant patients, with consideration of the physiological changes of pregnancy affecting anesthetic and surgical management. Methods: We reviewed the medical records of all pregnant patients undergoing laparoscopic surgery at Brigham and Womens Hospital between January 1, 1991 and April 30, 1995. Results: Laparoscopic cholecystectomy was performed without complication in ten patients (gestational age 9–30 weeks). Details of anesthetic and surgical management are described. The anesthetic and surgical implications of pregnancy-associated physiological changes in the gastrointestinal, respiratory, cardiovascular, and central nervous system are reviewed. Conclusions: With appropriate attention to the altered physiology of pregnancy, laparoscopic cholecystectomy can be performed safely and effectively during pregnancy.

Hemodynamics during laparoscopic surgery in pregnancy.

The association between central (cerebrospinal fluid [CSF]) and peripheral (plasma) levels of beta-endorphin-like immunoactivity (β-ELI) in nonpregnant women (n = 8) and pregnant women (a) at 16 to 20 weeks of gestation (n = 6), (b) at term (n = 21), and (c) in labor (n = 15) was investigated. Umbilical arterial (n = 11) and venous (n = 11) samples were also obtained. In agreement with previous investigations, it was found that plasma levels of β-ELI increased during labor (mean ± SEM: nonpregnant women, 63.5 ± 18.2; pregnant women at term, 64.0 ± 12.2; women in labor, 110.8 ± 30.3 pg/ml), and that levels of umbilical arterial plasma of β-ELI exceeded those in umbilical venous plasma (132.5 ± 34.0 versus 68.2 ± 22.2). However, CSF levels of β-ELI did not change over the course of pregnancy or during labor (nonpregnant women, 36.5 ± 15.8; pregnant women at 16 to 20 weeks of gestation, 60.1 ± 10.3; pregnant women at term, 57.5 ± 8.4; women in labor 48.5 ± 8.3 pg/ml). This evidence that plasma and CSF levels of β-ELI are dissociated during labor calls into question inferences regarding behavioral changes during parturition based on plasma β-ELI measurements.

Prophylactic antiemetics for laparoscopic cholecystectomy: a comparison of perphenazine, droperidol plus ondansetron, and droperidol plus metoclopramide

STUDY OBJECTIVE To test the hypothesis that alkalinization of lidocaine decreases the pain of skin infiltration in surgical patients. DESIGN Double-blind, randomized, prospective study. SETTING Preoperative holding units, Brigham and Womens Hospital. PATIENTS 184 adult surgical patients. INTERVENTIONS We compared the efficacy of 1% lidocaine with and without 0.1 mEq/ml of sodium bicarbonate (NaHCO3) for relief of pain of (1) skin infiltration and (2) intravenous (i.v.) catheterization prior to surgery. MEASUREMENTS AND MAIN RESULTS Patients evaluated the intensity of pain using a 100 mm visual analog scale (VAS). There were no differences between study groups (lidocaine with NaHCO3, n = 89; lidocaine alone, n = 95) with respect to site of catheterization or catheter gauge used. Lidocaine plus NaHCO3 caused significantly less pain on skin infiltration (median VAS = 4; range = 0 to 51) than did lidocaine alone (VAS = 8; range = 0 to 48; p < 0.008). Pain of i.v. catheterization also did not differ between groups. There was a weak correlation between catheter gauge and pain of i.v. catheterization (r = -0.19; p = 0.01). CONCLUSIONS Pain resulting from skin infiltration of lidocaine solutions can be diminished by adding NaHCO3. However, catheter size is more important than the presence or absence of NaHCO3 in determining the pain of i.v. catheterization.