Bruce Ben-David

Intrathecal fentanyl with small-dose dilute bupivacaine: better anesthesia without prolonging recovery.

Recent concern regarding lidocaine neurotoxicity has prompted efforts to find alternatives to lidocaine spinal anesthesia.Small-dose dilute bupivacaine spinal anesthesia yields a comparably rapid recovery profile but may provide insufficient anesthesia. By exploiting the synergism between intrathecal opioids and local anesthetics, it may be possible to augment the spinal anesthesia without prolonging recovery. Fifty patients undergoing ambulatory surgical arthroscopy were randomized into two groups receiving spinal anesthesia with 3 ml 0.17% bupivacaine in 2.66% dextrose without (Group I) or with (Group II) the addition of 10 micro g fentanyl. Median block levels reached T7 and T8, respectively (P = not significant [NS]). Mean times to two-segment regression, S2 regression, time out of bed, time to urination, and time to discharge were 53 vs 67 min (P < 0.01), 120 vs 146 min (P < 0.05), 146 vs 163 min (P = NS), 169 vs 177 min (P = NS), and 187 vs 195 min (P = NS) respectively. Motor blockade was similar between groups, but sensory blockade was significantly more intense in Group II (P < 0.01). Six of 25 blocks failed in Group I, whereas none failed in Group II. The addition of 10 micro g fentanyl to spinal anesthesia with dilute small-dose bupivacaine intensifies and increases the duration of sensory blockade without increasing the intensity of motor blockade or prolonging recovery to micturition or street fitness. Implications: Concerns about the neurotoxicity of lidocaine have prompted efforts to find alternatives to lidocaine spinal anesthesia. We studied 50 patients undergoing ambulatory surgical arthroscopy and found that although small-dose bupivacaine alone is inadequate for this procedure, the addition of fentanyl makes it reliable. (Anesth Analg 1997;85:560-5)

Spinal bupivacaine in ambulatory surgery: the effect of saline dilution.

The safety of lidocaine spinal anesthesia has recently been called into question by reports of both permanent and transient neurologic toxicity.This study explored the possibility of adapting the longer acting spinal bupivacaine to ambulatory surgery. Sixty patients presenting for ambulatory arthroscopy were randomized to four groups receiving the following spinal anesthetics: Group I (15 mg bupivacaine), 3 mL of 0.5% spinal bupivacaine in 8% dextrose; Group II (10 mg bupivacaine), 2 mL of the 0.5% spinal bupivacaine + 1 mL saline; Group III (7.5 mg bupivacaine), 1.5 mL of the 0.5% spinal bupivacaine + 1.5 mL saline; Group IV (5 mg bupivacaine), 1 mL of the 0.5% spinal bupivacaine + 2 mL saline. Maximum block height was T-5 in Group I versus T-8 in the other groups. Onset times to peak block were similar in all groups and averaged 14 min. Time to two-segment regression, complete regression, micturition, and discharge were significantly reduced from Group I to Group II and from Group II to Group III. Reductions in times between Groups III and IV did not achieve statistical significance. Times from placement of the spinal block until discharge were 471 +/- 35, 260 +/- 15, 202 +/- 14, and 181 +/- 8 min, respectively, for the four groups. The intensity of motor block decreased significantly from group to group, such that 13 of the 15 patients in Group IV failed to achieve Bromage level 2 or 3. The intensity of sensory block also decreased from group to group with four patients in Group IV having pain intraoperatively that required further treatment. Therefore, Group III provided the optimum combination of adequate depth of anesthesia and rapid recovery. The results of this study indicate that spinal anesthesia with 7.5 mg of 0.5% bupivacaine in 8% dextrose diluted with an equal volume of saline provides an acceptable spinal anesthetic for ambulatory arthroscopy with a recovery profile appropriate to the ambulatory setting. (Anesth Analg 1996;83:716-20)

Low-dose bupivacaine-fentanyl spinal anesthesia for cesarean delivery

Background and Objectives: The hypotension following spinal anesthesia remains commonplace in cesarean delivery. Intrathecal opioids are synergistic with local anesthetics and intensify sensory block without increasing sympathetic block. The combination makes it possible to achieve spinal anesthesia with otherwise inadequate doses of local anesthetic. We hypothesized that this phenomenon could be used to provide spinal anesthesia for cesarean delivery while incurring less frequent hypotension. Methods: Thirty‐two women scheduled for cesarean delivery were divided into 2 groups of patients who received a spinal injection of either 10 mg of isobaric (plain) bupivacaine 0.5% or 5 mg of isobaric bupivacaine with 25 μg fentanyl added. Each measurement of a systolic blood pressure less than 95 mm Hg or a decrease in systolic pressure of greater than 25% from baseline was considered as hypotension and treated with a bolus of 5 to 10 mg of intravenous ephedrine. Results: Spinal block provided surgical anesthesia in all patients. Peak sensory level was higher (T3 v T4.5) and motor block more intense in the plain bupivacaine group. The plain bupivacaine patients were more likely to require treatment for hypotension (94% v 31%) and had more persistent hypotension (4.8 v 0.6 hypotensive measurements per patient) than patients in the minidose bupivacaine‐fentanyl group. Mean ephedrine requirements were 23.8 mg and 2.8 mg, respectively, for the 2 groups. Patients in the plain bupivacaine group also complained of nausea more frequently than patients in the minidose bupivacaine‐fentanyl group (69% v 31%). Conclusions: Bupivacaine 5 mg + fentanyl 25 μg provided spinal anesthesia for cesarean delivery with less hypotension, vasopressor requirements, and nausea than spinal anesthesia with 10 mg bupivacaine.

Minidose Bupivacaine–Fentanyl Spinal Anesthesia for Surgical Repair of Hip Fracture in the Aged

Background Spinal anesthesia for surgical repair of hip fracture in the elderly is associated with a high incidence of hypotension. The synergism between intrathecal opioids and local anesthetics may make it possible to achieve reliable spinal anesthesia with minimal hypotension using a minidose of local anesthetic. Methods Twenty patients aged ≥ 70 yr undergoing surgical repair of hip fracture were randomized into two groups of 10 patients each. Group A received a spinal anesthetic of bupivacaine 4 mg plus fentanyl 20 &mgr;g, and group B received 10 mg bupivacaine. Hypotension was defined as a systolic pressure of < 90 mmHg or a 25% decrease in mean arterial pressure from baseline. Hypotension was treated with intravenous ephedrine boluses 5–10 mg up to a maximum 50 mg, and thereafter by phenylephrine boluses of 100–200 &mgr;g. Results All patients had satisfactory anesthesia. One of 10 patients in group A required ephedrine, a single dose of 5 mg. Nine of 10 patients in group B required vasopressor support of blood pressure. Group B patients required an average of 35 mg ephedrine, and two patients required phenylephrine. The lowest recorded systolic, diastolic, and mean blood pressures as fractions of the baseline pressures were, respectively, 81%, 84%, and 85%versus 64%, 69%, and 64% for group A versus group B. Conclusions A “minidose” of 4 mg bupivacaine in combination with 20 &mgr;g fentanyl provides spinal anesthesia for surgical repair of hip fracture in the elderly. The minidose combination caused dramatically less hypotension than 10 mg bupivacaine and nearly eliminated the need for vasopressor support of blood pressure.

A Randomized Controlled Trial Comparing the ProSeal™ Laryngeal Mask Airway with the Laryngeal Tube Suction in Mechanically Ventilated Patients

Background:The ProSeal™ Laryngeal Mask Airway (PLMA) (Laryngeal Mask Company, Henley-on-Thames, United Kingdom) is a new laryngeal mask with a modified cuff designed to improve its seal and a drain tube for gastric tube placement. Similarly, the Laryngeal Tube Suction (LTS) (VBM Medizintechnik Gmbh, Sulz a.N, Germany) is a new laryngeal tube that also has an additional channel for gastric tube placement. This study compared the placement and functions of these two devices. Methods:One hundred fifty patients undergoing general anesthesia for elective surgery were randomly allocated to the PLMA (n = 75) or LTS (n = 75). Oxygenation and ventilation, ease of insertion, fiberoptic view, oropharyngeal leak pressure, ventilatory data, ease of gastric tube insertion, and postoperative airway morbidity were determined. Results:After successful insertion of the devices in 96% of patients with the PLMA and in 94.4% with the LTS it was possible to maintain oxygenation, ventilation, and respiratory mechanics during the entire duration of surgery. Successful first and second attempt insertion rates were 57 patients (76%) and 15 patients (20%), respectively, for the PLMA and 60 patients (80%) and 11 patients (14.6%), respectively, for the LTS. Airway placement was unsuccessful with the PLMA in three patients and with the LTS in four patients. Time to achieve an effective airway was 36 ± 24 s with the PLMA versus 34 ± 25 s with the LTS. Gastric tube insertion was possible in 97.3% of patients with the PLMA and in 96% with the LTS. Conclusions:With respect to both physiologic and clinical function, the PLMA and LTS are similar and either device can be used to establish a safe and effective airway in mechanically ventilated anesthetized adult patients.

A comparison of minidose lidocaine-fentanyl and conventional-dose lidocaine spinal anesthesia.

The syndrome of transient neurologic symptoms (TNS) after spinal lidocaine has been presumed to be a manifestation of local anesthetic neurotoxicity. Although TNS is not associated with either lidocaine concentration or dose, its incidence has never been examined with very small doses of spinal lidocaine. One hundred ten adult ASA physical status I and II patients presenting for arthroscopic surgery of the knee were randomly assigned to receive spinal anesthesia with either 1% hypobaric lidocaine 50 mg (Group L50) or 1% hypobaric lidocaine 20 mg + 25 &mgr;g fentanyl (Group L20/F25). Hemodynamic data, block height and regression, and time to first micturition and discharge were recorded. Follow-up phone calls were made by a blinded researcher at 48–72 h using a standardized questionnaire. Both groups had a median peak cephalad block level of T10. Lidocaine 50 mg was associated with a greater decrease in systolic blood pressure and a greater need for ephedrine. Time until block regression to the S2 dermatome (80 vs 110 min) and outpatient time to void (130 vs 162 min) and discharge (145 vs 180 min) were faster in the L20/F25 group. Complaints of TNS were found in 32.7% of the patients in the L50 group and in 3.6% of the patients in the L20/F25 group. We conclude that spinal anesthesia with lidocaine 20 mg + fentanyl 25 &mgr;g provided adequate anesthesia with greater hemodynamic stability and faster recovery than spinal anesthesia with lidocaine 50 mg. The incidence of TNS after spinal lidocaine 20 mg + fentanyl 25 &mgr;g was significantly less than that after spinal lidocaine 50 mg. Implications The use of a small-dose lidocaine plus fentanyl combination for spinal anesthesia provides greater hemodynamic stability, faster recovery, and a significantly reduced incidence of transient neurologic symptoms than a conventional dose (50 mg) of spinal lidocaine.

The Influence of High Spinal Anesthesia on Sensitivity to Midazolam Sedation

We tested whether a high spinal anesthesia may alter the susceptibility to the soporific effects of sedatives.Twenty ASA grade I and II women undergoing elective abdominal hysterectomy were randomly allocated into two groups. Patients in Group I were given a subarachnoid injection of 12 mg hyperbaric tetracaine and those patients who after 10 min had a sensory level of T4-6 (10 patients) were included in the study. Ten additional patients (Group II) received no spinal injection. Induction of anesthesia was performed on all patients by injecting 1 mg of midazolam intravenously every 30 s until the patient failed to respond to three repeated commands to squeeze the anesthetists hand. This was considered the induction dose or end-point for the purposes of the study. Patients were then given a neuromuscular blocker, ventilated with oxygen, nitrous oxide, and a volatile anesthetic, tracheally intubated, and maintained under general anesthesia for the remainder of the operation. The dose of midazolam administered to the point of patient failure to respond to command was 7.6 +/- 0.72 mg SEM for Group I and 14.7 +/- 1.16 mg SEM for Group II, (P < 0.0001). These results support the conclusion that patients having a high spinal anesthetic are more sensitive to the sedative effects of midazolam. (Anesth Analg 1995;81:525-8)

The Combitube in elective surgery: a report of 200 cases.

BackgroundThe Combitube has proved to be a valuable device for securing the airway in cases of difficult intubation. This study investigated the effectiveness of the Combitube in elective surgery during both mechanical and spontaneous ventilation. MethodsTwo hundred patients classified as American Society of Anesthesiologists physical status I and II, with normal airways, scheduled for elective surgery were randomly allocated into two groups: nonparalyzed, spontaneously breathing (n = 100); or paralyzed, mechanically ventilated (n = 100). After induction of general anesthesia and insertion of the Combitube, oxygen saturation, end-tidal carbon dioxide and isoflurane concentration, systolic and diastolic blood pressure and heart rate, as well as breath-by-breath spirometry data were obtained every 5 min. ResultsIn 97% of patients, it was possible to maintain oxygenation, ventilation, and respiratory mechanics, as well as hemodynamic stability during either mechanical or spontaneous ventilation for the entire duration of surgery. The duration of surgery was between 15 and 155 min. ConclusionsThe results of this study suggest that the Combitube is an effective and safe airway device for continued management of the airway in 97% of elective surgery cases.

Gabapentin therapy for vulvodynia.

V ulvar pain may be the presenting symptom of a variety of unrelated disorders (1). “Essential” vulvodynia or “burning vulva syndrome” is a chronic, idiopathic pain syndrome characterized by unremitting, diffuse burning of the vulva. Allodynia and hyperpathia are present despite a lack of clinical findings. The condition is accompanied by psychological disability, severe preoccupation with the pain, and limitation of daily activities. Its diagnosis is one of exclusion, particularly of chronic vestibulitis (2). Of the various therapies that have been recommended, none has been proven successful. Recently, the novel anticonvulsant gabapentin (GBP) has been reported effective in the treatment of a variety of chronic pain conditions, particularly those of neuropathic pain (3). Based on these encouraging reports and our conviction that vulvodynia represents an unexplained neuropathic process, we chose to try gabapentin treatment in a group of patients. This is the first published report of its use in vulvodynia.

Anesthesia and postoperative analgesia: outcomes following orthopedic surgery.

The demand for increased efficiency and decreased hospital stay has magnified the role of anesthesia and acute postoperative pain management in orthopedics. Orthopedic anesthesia and acute postoperative pain management, which are subspecialties of anesthesiology, are increasingly recognized for their positive effect on the length of hospital stay, functional recovery, and patient satisfaction. Recently, there has been a resurgence in the use of continuous nerve block techniques for postoperative pain management. These techniques have been shown to be effective and safe in controlling postoperative pain, both at rest and during physical therapy, even in anticoagulated patients. The use of peripheral nerve blocks for anesthesia has been associated with earlier discharge when compared with general anesthesia and neuraxial blocks in patients undergoing ambulatory orthopedic surgery. Regional techniques are usually part of a multimodal strategy that includes both pharmacological and nonpharmacological approaches to pain management.