Radha Sukhani

The effect of preoperative dexamethasone on the immediate and delayed postoperative morbidity in children undergoing adenotonsillectomy.

In this prospective, randomized, double-blind, placebo-controlled study, we examined the effect of preoperative dexamethasone on postoperative nausea and vomiting (PONV) and 24-h recovery in children undergoing tonsillectomy. One hundred thirty children, 2-12 yr of age, ASA physical status I or II, completed the study. All children received oral midazolam 0.5-0.6 mg/kg preoperatively. Anesthesia was induced with halothane and nitrous oxide in 60% oxygen and maintained with nitrous oxide and isoflurane. Intubation was facilitated by mivacurium 0.2 mg/kg. Each child received fentanyl 1 [micro sign]g/kg IV before initiation of surgery, as well as dexamethasone 1 mg/kg (maximal dose 25 mg) (steroid group) or an equal volume of saline (control group). Intraoperative fluids were standardized to 25-30 mL/kg lactated Ringers solution. All tonsillectomies were performed under the supervision of one attending surgeon using an electrodissection technique. Postoperatively, fentanyl and acetaminophen with codeine elixir were administered as needed for pain. Rescue antiemetics were administered when a child experienced two episodes of retching and/or vomiting. Before home discharge, the incidence of PONV, need for rescue antiemetics, quality of oral intake, and analgesic requirements did not differ between groups. However, during the 24 h after discharge, more patients in the control group experienced PONV (62% vs 24% in the steroid group) and complained of poor oral intake. Additionally, more children in the control group (8% vs 0% in the steroid group) returned to the hospital for the management of PONV and/or poor oral intake. The preoperative administration of dexamethasone significantly decreased the incidence of PONV over the 24 h after home discharge in these children. Implications: In this double blind, placebo-controlled study, we examined the efficacy of a single large dose (1 mg/kg; maximal dose 25 mg) of preoperative dexamethasone on posttonsillectomy postoperative nausea and vomiting (PONV) in children 2-12 yr of age undergoing tonsillectomy. Compared with placebo, dexamethasone significantly decreased the incidence of PONV in the 24 h after discharge, improved oral intake, decreased the frequency of parental phone calls, and resulted in no hospital returns for the management of PONV and/or poor oral intake. (Anesth Analg 1998;87:57-61)

Propofol versus propofol-ketamine sedation for retrobulbar nerve block: comparison of sedation quality, intraocular pressure changes, and recovery profiles.

UNLABELLED We compared sedation quality, intraocular pressure (IOP) changes, and recovery profiles in patients who received propofol or propofol-ketamine sedation during placement of the retrobulbar nerve block (RBB). Seventy elderly patients undergoing cataract extraction according to a prospective, randomized, double-blinded protocol were preoperatively evaluated with a Mini-Mental State examination and baseline IOP. A hypnotic dose was provided with either propofol (Group P) or a propofol-ketamine (Group PK) combination. The IOP measurement was repeated, and the surgeon initiated the RBB. Supplemental study drug was given if needed. The level of sedation was considered acceptable if the patient exhibited minimal or no movement and grimacing with needle insertion. Patients were evaluated in terms of quality of sedation, cardiopulmonary stability, and recovery profile. Compared with patients in Group P, patients in Group PK had a significantly faster onset of acceptable sedation (Group P 235 +/- 137 s versus Group PK 164 +/- 67 s) and required significantly less supplemental sedation (Group P 1.1 +/- 1.9 mL versus Group PK 0.15 +/- 0.3 mL). Additionally, none of the Group PK patients required ventilatory assistance, but two patients in Group P required assisted mask ventilation. In conclusion, the addition of ketamine (13.2 +/- 3.3 mg) to propofol (44 +/- 11 mg) decreased the hypnotic requirement and improved the quality of sedation without prolonging recovery. IMPLICATIONS Anesthesiologists frequently perform retrobulbar blocks while simultaneously providing sedation. Using ketamine to supplement propofol sedation provided a faster onset and improved the quality of sedation during the retrobulbar block procedure.

Recovery after propofol with and without intraoperative fentanyl in patients undergoing ambulatory gynecologic laparoscopy.

This prospective, randomized double-blind study was conducted to examine the effect of intraoperative opioid (fentanyl) supplementation on postoperative analgesia, emesis, and recovery in ambulatory patients receiving propofol-nitrous oxide anesthesia. Eighty patients undergoing ambulatory gynecologic laparoscopy participated. Confounding variables that could influence the incidence of postoperative emesis were controlled. Patients received either fentanyl 100 micro g (Group I) or ketorolac 60 mg (Group II) intravenously (IV) at the time of anesthetic induction. No further analgesic supplements were given intraoperatively. Anesthesia was induced with propofol and maintained with propofol-nitrous oxide. Atracurium was used for muscle relaxation and reversed with neostigmine and glycopyrrolate. Postoperative pain during early recovery was treated with IV fentanyl 25-50 micro g (Group I) or IV ketorolac 15-30 mg (Group II). Subsequent breakthrough pain in both groups was treated with IV fentanyl 25 micro g increments as needed (rescue analgesia). Eighty-four percent of patients in Group I required analgesics during early recovery versus 56% of patients in Group II (P < 0.05). Maintenance dose of propofol was significantly lower in Group I (129 +/- 35 micro g [centered dot] kg-1 [centered dot] min-1) than in Group II (170 +/- 63 micro g [centered dot] kg-1 [centered dot] min-1). Immediate recovery (emergence) in the two groups was comparable, despite different propofol requirements. Although the incidence of emetic sequelae in the postanesthesia care unit was not significantly different between the two treatment groups, a significantly larger number of patients in Group I (fentanyl group) had emetic sequelae that required therapeutic intervention (Group I 29% versus Group II 10%). Patients in Group I also took a significantly longer time to ambulate and meet criteria for home discharge. These results indicate that, in patients undergoing ambulatory gynecologic laparoscopy, the practice of administering a small dose of fentanyl at the time of anesthetic induction reduces maintenance propofol requirement, but fails to provide effective postoperative analgesia. Fentanyl administration at anesthetic induction increased the need for rescue antiemetics. The relative severity of emetic sequelae could have contributed to delay in ambulation and discharge. (Anesth Analg 1996;83:975-81)

Propofol for ambulatory gynecologic laparoscopy: does omission of nitrous oxide alter postoperative emetic sequelae and recovery?

The role of nitrous oxide in postoperative emesis is controversial. This prospective randomized study was performed to compare the emetic sequelae and quality of recovery between a group of patients anesthetized with propofol alone and a group anesthetized with propofol plus nitrous oxide. Seventy patients, ASA grade I or II, scheduled for ambulatory gynecologic laparoscopy under general anesthesia were included. Most factors which could influence the incidence of postoperative emesis were controlled. The overall incidence of emetic sequelae during the first 24 h postoperatively was 25% in the group anesthetized with propofol alone versus 29% for the group anesthetized with propofol and nitrous oxide. The incidence of emetic sequelae requiring therapeutic intervention was 13% and 6%, respectively. This difference was not statistically significant. The group of patients who received propofol alone required an average propofol dose of 221.5 +/- 71.9 micrograms.kg-1.min-1 to maintain anesthesia compared with 162.5 +/- 43.9 micrograms.kg-1.min-1 for the group receiving propofol plus nitrous oxide (P < 0.001). The time from discontinuation of propofol to eye-opening and orientation was significantly longer in patients anesthetized with propofol alone. Otherwise, the recovery variables were comparable between the two groups. We conclude that supplementing propofol with nitrous oxide in patients undergoing ambulatory laparoscopy reduces the requirements of propofol, expedites immediate recovery (emergence), and does not increase the incidence of postoperative emesis. This tends to confirm that there is no clinical advantage to omitting nitrous oxide.

Incidence and Etiology of Failed Spinal Anesthetics in a University Hospital: A Prospective Study

Two recent retrospective reports on the incidence of failed spinal anesthetics that indicated extremely variable results prompted the present prospective study of 200 consecutive spinal anesthetics to determine the incidence and causes of failed spinal anesthetics.Tetracaine was the spinal anesthetic agent utilized in all cases — crystalline tetracaine (Niphanoid) in 71% and a 1% solution in 19% of the cases. The failure rate overall was 4%, with all failures being due to anesthetic factors, both technical and pharmacologic. However, only 25% of the failures were due to errors in technique, and 75% were due to errors in judgment with respect to pharmacologic factors (dosage, use of epinephrine, and/or positioning of the patient). Our data, therefore, differ from those of Levy et al. (Anesth Analg 1985;64:705–10), both in terms of failure rate, which is 25% of theirs, and in terms of causation, with our data indicating errors in judgment to be the causative factor three times as often as errors in technique. Presumably, this difference is due to the greater experience in spinal anesthesia that a resident receives at our institution.

Lidocaine disposition following intravenous regional anesthesia with different tourniquet deflation technics

It has been claimed that tourniquet cycling, cyclic deflation and reinflation of the tourniquet at the termination of intravenous regional anesthesia (IVRA), enhances the safety of IVRA by minimizing the peak blood level of local anesthetics. To evaluate the validity of these claims and to determine the optimal cycling technic, peak arterial (Cmax) plasma concentrations of lidocaine were determined as well as the time to reach these peaks (Tmax) utilizing contralateral radial arterial blood samples in three groups of volunteers after 30 minutes of IVRA: In all three groups IVRA was induced with 3 mg/kg of lidocaine and maintained for 30 min. In the first group the tourniquet was then simply deflated once (and not reinflated); in the second group the tourniquet was deflated three times with variable periods of deflation (0, 10 and 30 seconds) separated by 1-minute periods of reinflation; and in the third group the tourniquet was again deflated 3 times but with fixed periods of deflation (10 sec) separated by 1 min periods of reinflation. The results obtained indicate that cycling technics do not appear to significantly reduce Cmax, but they do significantly prolong Tmax. Of the two cycling technics, the 10-second deflation interval technic appeared to be superior, both clinically and pharmacologically, as it was associated with less venous congestion and therefore less discomfort, and it sequentially decreased the arterial plasma concentration of lidocaine with each subsequent deflation-reinflation cycle.

Prolonged Horner's syndrome after interscalene block : a management dilemma

he interscalene approach to brachial plexus block as described by Winnie (1) is a valuable T anesthetic technique for shoulder surgery, since it can provide intraoperative anesthesia as well as prolonged postoperative analgesia. Reversible neural complications, such as phrenic nerve block, recurrent laryngeal nerve block, and cervical sympathetic block presenting as Horner ’s syndrome, are not unusual with interscalene block, especially when larger volumes of local anesthetics are employed. Horner’s syndrome occurs with a frequency of 60%-75% with supraclavicular techniques of brachial plexus block (2,3). The clinical manifestations of Horner’s syndrome are usually temporary and not of much concern to the patient or to the anesthesiologist, since they do not cause significant patient discomfort. We recently encountered a patient who developed prolonged Horner ‘s syndrome after interscalene block. The case presented a diagnostic as well as a therapeutic dilemma. A pharmacologic intervention described in the anesthesia literature failed to resolve the patient’s ptosis (4).

Is succinylcholine after pretreatment with d-tubocurarine and lidocaine contraindicated for outpatient anesthesia?

Because succinylcholine has obvious advantages for facilitating endotracheal intubation in the ambulatory setting (e.g., low cost, fast onset, and no need for reversal of neuromuscular block), it is important to determine whether this muscle relaxant is indeed associated with an increased incidence of postoperative myalgias, compared with alternative but more expensive nondepolarizing muscle relaxants. We studied 119 outpatients undergoing endoscopic nasal sinus surgery or septoplasty. The anesthetic technique consisted of propofol/lidocaine for induction, followed by isoflurane/nitrous oxide/oxygen for maintenance. Oral tracheal intubation was performed by using a fiberscope. Patients were randomly assigned to one of two muscle relaxant groups. Group 1 patients received d-tubocurarine 3 mg followed by succinylcholine 1.5 mg/kg. Group 2 patients received mivacurium 0.2 mg/kg. After recovery from anesthesia, patients were asked whether they had any muscle pain and/or stiffness. Pain was categorized by location and quantified by using a verbal scale (from 0 to 10). Analgesic usage and myalgias limiting ambulation were recorded. After discharge from the ambulatory surgery unit, patients were contacted by telephone on Postoperative Day 1. If patients complained of myalgias, they were contacted by telephone on Days 2 and 3. Only one patient (in the mivacurium-treated group) reported myalgia as a limiting factor in ambulation or resumption of normal activity. There were no differences between groups with respect to the incidence (21% in the succinylcholine-treated group and 18% in the mivacurium-treated group), location, or severity of myalgia. In conclusion, succinylcholine (preceded by pretreatment with d-tubocurarine and lidocaine) is not associated with an increased incidence of myalgias, compared with mivacurium, when used to facilitate tracheal intubation in patients undergoing ambulatory nasal surgery. Implications The results of this study show that the frequency of muscle pains after surgery in outpatients is approximately 20%, regardless of whether succinylcholine (after precurarization) or mivacurium is used to assist in insertion of the breathing tube.

Clinical pharmacokinetics of carbonated local anesthetics III: interscalene brachial block model

&NA; To compare serum levels of lidocaine resulting from 1.1% lidocaine carbonate and 1.0% lidocaine hydrochloride, the two salts were administered to ten healthy adult patients undergoing upper extremity surgery under interscalene brachial plexus block. Epinephrine (1:200,000) was added to both the solutions just prior to injection, and, following performance of the blocks, venous blood samples were drawn at 3, 5, 10, 15, 20, 30, 60 and 120 minutes. The concentration of lidocaine tended to rise more rapidly and to achieve higher levels in the first 10 minutes following injection of the carbonated lidocaine. However, no significant differences were found in the parameters of Cmax, Tmax or AUC for the two salts, and the serum levels in both groups at all times were well below the levels known to produce systemic toxicity. Therefore, while previous studies appear to indicate that the carbonate salt enhances diffusion, penetration, and uptake of neural tissues as compared with the hydrochloride salt, the present study indicates that vascular uptake is not similarly affected.

Caudal anesthesia and urinary retention in ambulatory surgery.

Voiding intervals in children receiving caudal anesthesia are variable, but urinary retention requiring therapeutic intervention has not been reported (1,2). Caudal anesthesia is, however, frequently implicated when urinary retention occurs after discharge. To determine the incidence of voiding difficulties and the contribution of perioperative factors, a retrospective survey of the postoperative course of 326 children (<12 yr) undergoing urological surgery and inguinal herniorrhaphy was conducted. Data were collected from anesthesia records, recovery room data sheets, and quality assurance data sheets designed to monitor recovery 24 h after discharge. Recorded variables were demographics, type and duration of surgery, local anesthetic drug and adjunct (epinephrine), type of analgesia-caudal versus local anesthetic infiltration, use of autonomic drugs (atropine, reversal drugs), amount of intravenous fluids, and postoperative voiding difficulties. Caudal anesthesia was administered to 237 children, and local anesthesia was administered to 63 children. Twenty-six children who did not undergo either of the two analgesic techniques were excluded. The study variables were comparable between the two groups. Bupivacaine 0.25% was used in all cases. Postoperative voiding difficulties were identified in seven children (9-22 h after discharge), five (2%) in the caudal group and two (3%) in the local group. Urinary retention (bladder distension and dribbling) requiring invasive intervention (catheterization/suprapubic drainage) occurred predominately in children undergoing hypospadias repair; four (6%) children required such intervention. In comparison, only 1 of the 233 children who underwent other surgical procedures required invasive intervention (single catheterization) for urinary retention (P < 0.01). Although commonly implicated, caudal anesthesia was found to have no correlation with the incidence of postoperative urinary retention in this retrospective study. There was, however, a distinct correlation between urinary retention and type of surgery, with patients undergoing hypospadias repair having the highest incidence of urinary retention requiring therapeutic intervention.