Rapacuronium recovery characteristics and infusion requirements during inhalation versus propofol-based anaesthesia.

We examined the effect of four maintenance anaesthetics on the neuromuscular blocking activity and spontaneous recovery characteristics after a short-term infusion of rapacuronium. Eighty ASA I-III adult patients undergoing elective surgery were studied at four centres. Anaesthesia was induced with propofol 1.5-2.5 mg kg-1 and fentanyl 1-2 micrograms kg-1, followed by a bolus of rapacuronium 1.5 mg kg-1. The patients were randomized to receive either desflurane (2-4% end-tidal, ET), sevoflurane (0.75-1.5% ET), isoflurane (0.4-0.8% ET), or a propofol infusion (75-150 micrograms kg-1 min-1) for maintenance of anaesthesia in combination with nitrous oxide (60-70%) in oxygen. When the first twitch (T1) of a train-of-four stimulus (using the TOF Guard accelerometer) returned to 5%, an infusion of rapacuronium was started at 3 mg kg-1 h-1 and adjusted to maintain T1/T0 at 10%. The duration of infusion lasted between 45 and 60 min, and the average infusion rates of rapacuronium were similar in all groups, ranging from 1.6 to 2.5 mg kg-1 h-1. There were no significant differences among the groups in the times for T1/T0 to return to 25%, 75% or 90%, or for T4/T1 to return to 70% and 80% upon discontinuation of the infusion. When potent inhalation anaesthetics are used in clinically relevant concentrations for maintenance of anaesthesia, the neuromuscular recovery profile of rapacuronium administered as a variable-rate infusion for up to 1 h is similar to that found with a propofol-based anaesthetic technique.

Bisulfite-containing propofol: is it a cost-effective alternative to Diprivan for induction of anesthesia?

UNLABELLED: Propofol (Diprivan(TM); AstraZeneca, Wilmington, DE) is a commonly used drug for the induction of general anesthesia in the ambulatory setting. With the availability of a new bisulfite-containing generic formulation of propofol, questions have arisen regarding its cost effectiveness and safety compared with Diprivan(TM). Two hundred healthy outpatients were randomly assigned, according to a double-blinded protocol, to receive either Diprivan(TM) or bisulfite-containing propofol 1.5 mg/kg IV as part of a standardized induction sequence. Maintenance of anesthesia consisted of either desflurane (4%-8% end-tidal) or sevoflurane (1%-2% end-tidal) in combination with a remifentanil infusion (0.125 microg x kg(-1) x min(-1) IV). Patient assessments included pain on injection, induction time, hemodynamic and bispectral electroencephalographic changes during induction, emergence time, and incidence of postoperative nausea and vomiting. The two propofol groups were comparable demographically, and the induction times and bispectral index values during the induction were also similar. However, the bisulfite-containing formulation was associated with less severe pain on injection (5% vs 11%), with fewer patients recalling pain on injection after surgery (38% vs. 51%, P<0.05). None of the patients manifested allergic-type reactions after the induction of anesthesia. The acquisition cost (average wholesale price in US dollars) of a 20-mL ampoule of Diprivan(TM) was $15 compared with $13 for the bisulfite-containing propofol formulation. Therefore, we concluded that the bisulfite-containing formulation of propofol is a cost-effective alternative to Diprivan(TM) for the induction of outpatient anesthesia. IMPLICATIONS: Bisulfite-containing propofol and Diprivan(TM) (AstraZeneca, Wilmington, DE) were similar with respect to their induction characteristics; however, the generic formulation was associated with a smaller incidence of injection pain. Assuming that the drug costs are similar, these data suggest that the bisulfite-containing formulation of propofol is a cost-effective alternative to Diprivan(TM).

A comparison of the costs and efficacy of ondansetron versus dolasetron for antiemetic prophylaxis.

UNLABELLED: The optimal dose and timing of 5-HT(3) antagonist administration for prophylaxis against postoperative nausea and vomiting (PONV) remains controversial. Although 5-HT(3) antagonists seem to be most effective when administered near the end of surgery, there are no data on the comparative efficacy or costs associated with the 5-HT(3) antagonists dolasetron and ondansetron when administered at the end of the operation. In this double-blinded study, 200 outpatients undergoing otolaryngologic procedures with a standardized general anesthetic received 4 (O4) or 8 mg (O8) of ondansetron or 12.5 (D12.5) or 25 mg (D25) of dolasetron IV within 30 min before the end of surgery. A blinded observer recorded the emetic episodes, maximum nausea score, recovery room resource and drug use, nursing time spent managing PONV, times to achieve discharge criteria from the Phase 1 and 2 recovery units, postdischarge emesis, and patient satisfaction. Total costs were calculated by using the perspective of a free-standing surgicenter. There were no differences in patient demographics, incidence of PONV, need for rescue medications, time spent in the recovery areas, unanticipated hospital admissions, or patient satisfaction among the four treatment groups. The mean total costs (95% confidence intervals) to prevent PONV in one patient were lowest in the D12.5 group: $23.89 (17.18-28.79) vs $37.81 (30.29-45.32), $33.91 (28.92-39.35), and $75.18 (61.13-89.24) for D25, O4, and O8, respectively. Excluding nursing labor costs did not alter this finding: $18.51 (14.18-22.85), $34.77 (28.03-41.49), $31.77 (28. 92-39.35), and $71.76 (58.17-85.35) for D12.5, D25, O4, and O8, respectively. We conclude that 12.5 mg of dolasetron IV is more cost effective than 4 mg of ondansetron IV for preventing PONV after otolaryngologic surgery and is associated with similar patient satisfaction. IMPLICATIONS: When administered at the end of surgery, 12.5 mg of dolasetron IV is as effective as 25 mg of dolasetron IV, 4 mg of ondansetron IV, and 8 mg of ondansetron IV in preventing emetic symptoms after otolaryngologic surgery and was associated with similar patient satisfaction at a reduced cost. There were no differences in the antiemetic efficacy of the 4 and 8 mg doses of ondansetron.

Use of the cuffed oropharyngeal airway as an alternative to the laryngeal mask airway with positive-pressure ventilation.

BACKGROUND: The cuffed oropharyngeal airway is a modified Guedel-type oral airway with a cuff at its distal end. The objectives of this study were to compare the ability of the cuffed oropharyngeal airway and the laryngeal mask airway to provide positive-pressure ventilation during general anesthesia, and to assess their relative ease of use and ability to reduce total fresh gas flow rates. METHODS: In this prospective, randomized study, a cuffed oropharyngeal airway (n = 25) or a laryngeal mask airway (n = 25) device was inserted after induction of anesthesia intravenously using 2 mg/kg propofol. While anesthesia was maintained with sevoflurane and nitrous oxide, the leak pressure, leak fraction (the fractional difference between the inspired and expired tidal volume), minimum fresh gas flow rate, and need for airway manipulations were determined. The anesthesia provider who inserted the device completed an evaluation form at the end of the 15-min study period. RESULTS: Positive-pressure ventilation was established successfully on the first attempt in 92% of the patients when the cuffed oropharyngeal airway was used and in 88% of the patients when the laryngeal mask airway device was used. However, manipulations of the airway device were necessary more frequently (8 vs. 1 patient; P < 0.05) and the leak pressure was less (22 +/- 6 cm water vs. 26 +/- 5 cm water; P < 0.05) with the cuffed oropharyngeal airway than with the laryngeal mask airway. In addition, the leak fraction (0.19 +/- 0.18 vs. 0.31 +/- 0.22; P < 0.05) and the minimum fresh gas flow rate (1.3 +/- 1.5 vs. 2.4 +/- 2.5; P = 0.12) were less in the laryngeal mask airway group. CONCLUSIONS: Positive-pressure ventilation is possible with the laryngeal mask airway and cuffed oropharyngeal airway devices. Although the cuffed oropharyngeal airway can be inserted easily by inexperienced users with a high first-attempt success rate (> 90%), manipulations of the device may be required to maintain a patent airway. The laryngeal mask airway device allows positive-pressure ventilation at slightly greater peak inspiratory pressures.

Safety considerations and fluid resuscitation in liposuction: an analysis of 53 consecutive patients.

There is no agreement as to appropriate fluid resuscitation in patients undergoing liposuction. This has assumed greater significance, as surgeons have undertaken larger volume aspirations (> or = 4 liters) and the potential complications of hypovolemia and fluid overload have materialized. This prospective study of 53 consecutive healthy patients undergoing liposuction using a superwet technique served to develop general guidelines for safe perioperative fluid management, especially in regard to large-volume aspirations. In this context, "aspirate" is defined as the total fat and fluid that is removed during liposuction. All patients were monitored using standard noninvasive hemodynamic monitoring. Thirty-six patients were monitored perioperatively with Foley catheters. The 53 patients underwent liposuction alone. We did not include patients who underwent concurrent aesthetic surgical procedures because our intention was to establish fluid administration guidelines for the liposuction patient. There were no significant complications in our series. The intraoperative fluid ratio, defined as (intravenous fluid + infiltrate)/aspirate, was 2.1 for the small-volume group and 1.4 for the large-volume group. These values were significantly different (p < .001, t test). Average urine output in the operating room and recovery room and on the floor was satisfactory (> 0.5 to 1 cc/kg/hr) and did not relate to volume aspirated (p = 0.21, 0.91, and 0.6, respectively, t test). Four patients who underwent "large-volume" aspirations (> or = 4 liters) had transient hypotension, which was immediately responsive to crystalloid fluid boluses in the first postoperative hours. All other patients required only maintenance intravenous crystalloid postoperatively until oral intake had been resumed. There were no statistically significant differences in postoperative fluid administration between the small- and large-volume groups. Ninety-three percent of patients were discharged within 24 hours of surgery. Our suggested guidelines for fluid resuscitation based on this retrospective study are as follows: (1) small volume (< 4 liters aspirated): maintenance fluid + subcutaneous wetting solution; (2) large volume (> or = 4 liters aspirated): maintenance fluid + subcutaneous wetting solution + 0.25 cc of intravenous crystalloid per cc of aspirate removed after 4 liters. This formula has since been used in the care of 94 patients who have undergone liposuction exclusively. All patients have had unremarkable hospital courses. These guidelines do not replace sound clinical judgment. Good communication between the surgeon and anesthesiologist is critical to optimal patient care and safety.

Phenomenological and pharmacological study of provoked obsessive/anxiety symptoms in obsessive-compulsive disorder: a preliminary study.

BACKGROUND: Inclusion of obsessive-compulsive disorder (OCD) as an anxiety disorder in DSM-i.v. assumes that anxiety is the primary symptom of OCD; however, persuasive empirical evidence in support of this view has not been presented yet. In the present study we hypothesized that provoked anxiety symptoms respond better to intravenous diazepam than would provoked obsessions. We, therefore, reasoned that anxiety symptoms are secondary symptoms of OCD. METHODS: To test the hypothesis we designed a double-blind, randomized, placebo-controlled crossover study. Patients underwent four experimental conditions in which the sequence of symptom provocation and i.v. injection of (placebo or diazepam) were alternated. Baseline and i.v. injection-induced symptom changes were assessed using visual analogs. RESULTS: Obsessions and anxiety correlated strongly for all four experimental conditions in which the sequence of the symptom provocation and diazepam i.v. injections was alternated. i.v. diazepam injection before and after symptom provocation failed to preferentially modulate anxiety symptoms over obsessions. Unexpectedly, in the group in which i.v. diazepam injection preceded the symptom provocation, reduction of mean obsessions was even more pronounced. CONCLUSIONS: Strong correlations between anxiety and obsessions at baseline, during symptom provocation, and after i.v. diazepam infusion suggest that anxiety and obsessions are tightly coupled phenomena in OCD.

Optimal dose of nicardipine for maintenance of hemodynamic stability after tracheal intubation and skin incision.

UNLABELLED: To determine the optimal dose of nicardipine (N) for maintenance of hemodynamic stability during the postinduction period, we designed a randomized, double-blind, placebo-controlled, dose-ranging study using four different doses of N administered after a standardized anesthetic induction sequence. A total of 106 patients were assigned to one of the following treatment groups: saline (control), N 0.5 mg (N0.5), N 1 mg (N1), N 2 mg (N2), and N 4 mg (N4). The study medication was administered intravenously (I.V.) in 2.5 mL of saline over 30 s 2 min before laryngoscopy. Mean arterial pressure (MAP) and heart rate (HR) were recorded at 1-min intervals for 15 min after tracheal intubation and for 5 min after skin incision. After intubation, the peak MAP values differed from the preinduction baseline MAP values by 21% +/- 20%, 9% +/- 12%, 1% +/- 13%, -10% +/- 12%, and -15% +/- 13% (mean +/- SD) in the control, N0.5, N1, N2, and N4 groups, respectively. However, the percent change in the pre- to postintubation MAP values (37% to 47%) was similar in all five groups. The highest postintubation HR values were recorded in the N4 group (P < 0.05 versus the other groups). However, the increases in MAP values after skin incision were the least in the N4 group. In conclusion, N1 I.V., administered 2 min before laryngoscopy provides optimal control of arterial blood pressure during the postinduction period. IMPLICATIONS: Acute increases in blood pressure during anesthesia are undesirable in patients with preexisting cardiovascular diseases. This double-blind study found that the calcium-channel blocker, nicardipine, 1 mg intravenously 2 min before tracheal intubation maintained hemodynamic stability during the intraoperative period.

Transdermal fentanyl system plus im ketorolac for the treatment of postoperative pain.

PURPOSE: To assess the safety and efficacy of transdermal fentanyl plus im ketorolac vs im ketorolac alone in the treatment of postoperative pain. METHODS: Ninety-two patients scheduled for surgery involving moderate to severe postoperative pain were randomized to one of two groups. Group A (n = 46) received an active fentanyl patch and group P (n = 46) received a placebo patch. Patches remained in place for 24 hr. Each patient received intraoperative ketorolac, 60 mg im. Patients were monitored for 36 hr postoperatively and the groups were analyzed for ketorolac usage, pain scores, vital signs, serum fentanyl concentrations, and adverse events. Intramuscular ketorolac was available on demand. RESULTS: Group A had lower pain scores at 8.12, 16 and 24 hr after patch placement (P < 0.05). Group A had lower heart rates, lower respiratory rates and fewer dropouts due to inadequate pain relief (4.3% vs 21.7% P < 0.05). Group A patients also used less ketorolac than group P patients (P < 0.05). The incidence of pruritus was higher in group A patients (19% vs 2%, P < 0.05), while the incidence of nausea and vomiting was not different between the two groups. Transdermal fentanyl was adequate "stand-alone" analgesia in only 23.8% of group A patients while 93.7% of the remaining group A patients receiving a combination of transdermal fentanyl and ketorolac had adequate pain relief. CONCLUSION: The transdermal fentanyl delivery system plus ketorolac im was more effective in controlling post-operative pain than ketorolac im alone. The two treatment modalities were comparable in safety with no difference in serious adverse events.

The effect of timing of ondansetron administration in outpatients undergoing otolaryngologic surgery.

A randomized, double-blind, placebo-controlled study was designed to compare the relative efficacy of prophylactic ondansetron, 4 mg intravenously (IV), when administered before induction of anesthesia or at the end of surgery to an outpatient population at high risk of developing postoperative nausea and vomiting (PONV). Patients undergoing otolaryngologic surgery were randomly assigned to one of three different treatment groups: Group 1 (placebo) received saline 5 mL prior to induction of anesthesia and again at the end of surgery; Group II received ondansetron 4 mg in 5 mL prior to induction of anesthesia and saline 5 mL at the end of surgery; and Group III received saline 5 mL prior to induction of anesthesia and ondansetron 4 mg at the end of surgery. All patients received the same general anesthetic technique. A standardized regimen of rescue antiemetics was administered in the recovery room to patients with > or = 2 emetic episodes or at the patients request for persistent nausea. Episodes of nausea and vomiting, as well as the need for rescue antiemetics, were recorded for 24 h after the operation. The incidences of nausea and emesis in the recovery room after prophylactic ondansetron, 4 mg IV, administered either before induction (68% and 20%, respectively) or at the end of surgery (60% and 4%, respectively) were not significantly decreased compared to the placebo control group (80% and 12%, respectively). However, when ondansetron was administered at the end of the operation, it significantly reduced the need for rescue antiemetics in the recovery room (36% vs 64% in the control group). The postanesthesia care unit and hospital discharge times were similar in all three study groups. One patients in Group II and one patient in Group III were hospitalized because of intractable symptoms related to PONV. After discharge from the ambulatory surgery unit, the incidence of nausea, vomiting, and the need for rescue antiemetic drugs were similar in all three treatment groups. In conclusion, ondansetron (4 mg IV) was more effective in reducing the need for rescue antiemetics in the recovery room when administered at the end versus prior to the start of otolaryngologic surgery. Therefore, when ondansetron is used for antiemetic prophylaxis in outpatients undergoing otolaryngologic procedures, it should be administered at the end of the operation rather than prior to induction of anesthesia.

Does monitoring end-tidal isoflurane concentration improve titration during general anesthesia?

STUDY OBJECTIVE: To assess the value of end-tidal anesthetic gas monitoring with respect to intraoperative hemodynamic stability and recovery times. DESIGN: Randomized blinded study. SETTING: Operating rooms at a university teaching hospital. PATIENTS: 120 ASA I and II patients receiving general anesthesia maintained with isoflurane and nitrous oxide (N2O). INTERVENTIONS: Following a standardized induction technique, patients were assigned to either an end-tidal isoflurane monitored (n = 60) or unmonitored (n = 60) group. During each operation, the anesthesiologist attempted to maintain an adequate "depth of anesthesia" by varying the administered concentration of isoflurane with or without information from an end-tidal isoflurane monitor. Intraoperative hemodynamic stability was assessed by determining the variation from a preincisional "baseline" mean arterial pressure (MAP) value established during a 10 minute interval immediately prior to the surgical incision. Recovery times were recorded from discontinuation of isoflurane and N2O until awakening, orientation, and postanesthesia care unit discharge. MEASUREMENTS AND MAIN RESULTS: Intraoperative hemodynamic stability was assessed in each patient and reported as the average error from the baseline MAP, absolute average error from the baseline MAP, coefficients of variation of heart rate (HR), systolic and diastolic MAP, and end-tidal isoflurane concentrations. Both study groups had similar intraoperative MAP and HR values, average error and coefficients of variation for the hemodynamic variables, as well as similar numbers of episodes of hypertension, hypotension, tachycardia, and bradycardia. Finally, the two groups were comparable with respect to early recovery times and postoperative side effects. CONCLUSIONS: This study suggests that end-tidal isoflurane monitoring does not improve the titration of isoflurane during general anesthesia.

Accommodation of time delay variations in automatic infusion of sodium nitroprusside.

A new self-tuning regulator for control of mean arterial blood pressure using sodium nitroprusside is presented. In addition to adapting to various patient response gains and time constants, the controller can accommodate variations in pure time delays, a problem that has not been addressed fully in previously proposed controllers. The control algorithm derivation is based on incorporating a self-tuning controller with an adaptive discrete time delay compensator. The derivation, however, is general and can potentially be applied to other pharmacological agents in addition to sodium nitroprusside. The a priori information required for implementation of the controller is the estimate of the order of the patient response transfer function and the range of the pure time delay. An attractive feature of the controller is its capability to optimize the level of the infused drug during the transient phase of the control without creating an output offset. This feature tends to reduce the overall level of the infused drug. Hence, it may be useful when the cost of a drug or its long-term administration side effects is of concern, such as in the case of sodium nitroprusside.

Effects of end-tidal gas monitoring and flow rates on hemodynamic stability and recovery profiles.

This study was designed to evaluate the impact of routine end-tidal anesthetic gas monitoring on the intraoperative hemodynamic stability and early recovery profile in 253 consenting ASA physical status I-III patients undergoing elective otolaryngologic procedures with isoflurane or enflurane anesthesia. Patients were randomly assigned to one of six treatment groups: Group I, monitored high-flow isoflurane; Group II, unmonitored high-flow isoflurane; Group III, monitored low-flow isoflurane; Group IV, unmonitored low-flow isoflurane; Group V, monitored low-flow enflurane; or Group VI, unmonitored low-flow enflurane. After a standardized induction sequence, anesthesia was maintained by administering variable concentrations of isoflurane or enflurane in an air/oxygen mixture at two different total gas flow rates (0.7 L/min or 3.5 L/min, respectively). Mean arterial pressure (MAP), heart rate (HR), and end-tidal (ET) anesthetic concentrations were recorded by a computer throughout the operation. The resident anesthesiologist was instructed to maintain an adequate "depth of anesthesia" by varying the administration of isoflurane (Groups I-IV) or enflurane (Groups V and VI) with or without end-tidal gas monitoring. Intraoperative hemodynamic stability was assessed in each patient and reported as the average error from the preincisional (baseline) MAP, average absolute error from the baseline MAP, coefficients of variation for HR, systolic, diastolic, and MAP values, and ET anesthetic concentrations. Recovery times from discontinuation of the volatile drug until awakening, following commands, and postanesthesia care unit (PACU) discharge were recorded. The six study groups had similar intraoperative MAP and HR values, coefficients of variation, and numbers of episodes of hypertension, hypotension, tachycardia, and bradycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Transdermal scopolamine for the reduction of postoperative nausea in outpatient ear surgery: a double-blind, randomized study.

We evaluated the effect of transdermal scopolamine on the incidence of postoperative nausea and vertigo after outpatient ear surgery (exploratory tympanotomy, mastoidectomy, or endolymphatic sac and oval and round window surgery) in a double-blind, placebo-controlled study. A transdermal patch containing either scopolamine (n = 19) or placebo (n = 20) was placed behind the nonsurgical ear 2 h before surgery. Anesthesia was induced with thiopental (4-6 mg/kg intravenously [i.v.]), sufentanil (0.5 microgram/kg i.v.), and vecuronium (0.1 mg/kg i.v.) and maintained with isoflurane (0.2%-2%) and nitrous oxide (70%) in oxygen. Patients were observed postoperatively in the recovery room and after discharge for 72 h. There was no significant difference between groups with respect to time in recovery room, time to discharge, incidence of in-house nausea, vomiting, amount of antiemetics required, or postoperative visual analog scale (VAS) scores while in the hospital. After discharge, there were lower VAS nausea scores (by repeat measures analysis, P < 0.05) and a lower reported incidence of nausea (31% vs 62%; P < 0.05) and vertigo (6.2% vs 25%; P < 0.05) in the active patch group versus the placebo group. There was a higher incidence of dry mouth in the active patch group (44% vs 25%). Seven patients did not complete the study due to failure to keep the patch in place or failure to return the diary from home; and one patient from the placebo patch group was admitted for uncontrolled nausea and vomiting. The authors concluded that transdermal scopolamine is effective in reducing, but not eliminating, postoperative nausea and vertigo after discharge in outpatient ear surgery.

Autonomic reflex dysfunction in patients presenting for elective surgery is associated with hypotension after anesthesia induction.

BACKGROUND: Autonomic reflex dysfunction in patients with diabetes is associated with an increased incidence of hypotension after induction of anesthesia. Whether this finding can be extrapolated to patients with autonomic dysfunction from other causes (e.g., advanced age, hypertension, altered ventricular function) has not been established. METHODS: The authors investigated whether autonomic reflex dysfunction in a more generalized patient group (26 consecutively consenting day-surgery patients older than 39 yr) was similarly associated with the occurrence of hypotension after induction. Preoperative tests of autonomic function included: Valsalva maneuver, change in heart rate with forced breathing, change in heart rate and blood pressure with standing, and spectral analysis of heart rate variability. Anesthesia was induced with 3-5 mg/kg thiopental, 2 micrograms/kg fentanyl, and 60% N2O; 0.1 mg/kg vecuronium was used for paralysis; 0-1.5% isoflurane was added for maintenance of anesthesia after intubation. Noninvasive measurements of mean blood pressure were obtained every minute for 10 min after induction and then every 3 min until skin incision. RESULTS: Twelve patients developed hypotension (mean blood pressure < 70 mmHg), and 14 patients did not. Measurements of autonomic reflex function were significantly more abnormal in the patients who developed hypotension (P < 0.006 for Valsalva measurements, heart rate variability parameters, and change in heart rate with forced breathing). Using critical test values for autonomic tests, the incidence of hypotension was 67-83% in patients with autonomic nervous system dysfunction versus 9-17% in other patients. CONCLUSIONS: The results document that: (1) some degree of autonomic reflex dysfunction is not uncommon in patients older than 39 yr presenting for elective surgery, and (2) such dysfunction is associated with an increased incidence of hypotension when using the described induction technique.

Influence of ketorolac tromethamine on clot elastic strength in humans as assessed by thromboelastography.

STUDY OBJECTIVE: To evaluate the effect of ketorolac tromethamine on coagulation using thromboelastography (TEG). DESIGN: TEGs were performed in each patient before and after ketorolac administration. Each patient's predrug results were used as control measurements for comparison with the postdrug results. SETTING: Medical center surgical unit. PATIENTS: Twenty ASA physical status I and II patients undergoing minor elective surgery; 12 healthy volunteers. INTERVENTIONS: TEGs were performed in all subjects before and 60 minutes after the intramuscular (IM) administration of ketorolac tromethamine 60 mg. Ten surgical patients were studied in the intraoperative period, and 10 surgical patients were studied in the postoperative period. The 12 healthy volunteers did not undergo a surgical procedure. MEASUREMENTS AND MAIN RESULTS: Specific parameters assessed from the TEGs were reaction time (R time), coagulation time (RK time), clot formation rate (angle of deflection), and maximum clot strength (maximum amplitude of deflection). Ketorolac administration did not cause statistically significant changes in these parameters in any of the three groups studied. CONCLUSIONS: IM administration of ketorolac tromethamine 60 mg did not significantly alter the speed of formation or viscoelastic strength of clots as measured by TEG. These results provide additional support for prior clinical studies confirming the safety of ketorolac administration in the perioperative period.