Changes in onset time of rocuronium in patients pretreated with ephedrine and esmolol--the role of cardiac output.

BACKGROUND: We investigated the hypothesis that manipulation of cardiac output (CO) with esmolol (Es) or ephedrine (E) affects the onset time of rocuronium. METHODS: Following anesthesia induction, 33 patients received E (70 micro g kg-1), Es (500 micro g kg-1) or placebo (P) 30 s before rocuronium (0.6 mg kg-1) administration. Cardiac output was measured non-invasively after intubation every 3 min. The interval from the end of rocuronium administration to the disappearance of all twitches was considered to be the onset time. RESULTS: Onset time was shorter after E (52.2 +/- 16.5 s) and longer after Es (114.3 +/- 11.1 s) compared with P (87.4 +/- 7.3 s) (P < 0.0001). Cardiac output increased (P < 0.05) in group E for 15 min after rocuronium. In group Es, CO decreased (P < 0.05) at 3 and 6 min. Cardiac output was higher in group E vs. group Es, 3-6 min post administration of rocuronium (P=0.015). CONCLUSION: Pretreatment with E or Es appears to affect the onset time of rocuronium by altering CO as measured with the NICO (Non-Invasive Cardiac Output) monitor (Novametrix Medical Systems Inc., Willingford, CO).

Celite-activated thrombelastography in children.

STUDY OBJECTIVE: To quantify global coagulation and establish normal ranges for the celite-activated thrombelastograph (TEG) in healthy pediatric patients. DESIGN: Prospective observational study. SETTING: Operating suite of a university-based hospital. PATIENTS: 110 healthy pediatric patients in four age groups and 25 healthy adult patients. INTERVENTIONS: Blood sampling for the celite-activated TEG was carried out after anesthetic induction. MEASUREMENTS: TEG indices: R time (reflecting time to fibrin formation), K time and alpha angle (fibrinogen-platelet interaction), maximum amplitude (reflecting maximal clot strength, platelet and fibrinogen function), TEG index (mathematical incorporation of the prior four measurements), and percent fibrinolysis at 30 minutes, were all recorded. MAIN RESULTS: Statistically significant differences between <12-month group in angle (compared to 25-48 month group) and % fibrinolysis (compared to all other pediatric groups). Significant differences in angle between two pediatric groups and adult group, and in the TEG index between three pediatric groups and adult group (all differences p < 0.05). CONCLUSIONS: These data identify changes of small magnitude in three celite-TEG parameters in healthy children compared to adults, without implication of abnormal coagulation between groups. Changes do not seem to be consistently related to age and will be useful for clinicians using the TEG to monitor (ab) normal coagulation in pediatric patients.

Sonoclot analysis in healthy children.

UNLABELLED: Although use of the Sonoclot device (Sienco, Inc., Morrison, CO) has been reported in isolated pediatric cases and in small reports in neonates, there are no published data for normal pediatric patients. As the device is used in situations of abnormal coagulation, such as cardiac and liver transplantation surgery, our aim was to determine normal data ranges in healthy pediatric surgical patients. Blood was withdrawn after anesthetic induction, and the Sonoclot activated clotting time, rate of clot formation, time to peak amplitude, and peak amplitude was compared among four pediatric groups (< 12 mo, 13-24 mo, 25-48 mo, 49 mo-9 yr) and an adult group. The Sonoclot activated clotting time in the < 12-mo and the Adult groups were shorter than the oldest group of children (P < 0.05), although all were within the anticipated normal range, and there were no significant differences in clot rate, peak amplitude, and time to peak amplitude among groups without apparent trends with increasing age. These Sonoclot variables quantify adequate global clot formation in pediatric patients and will facilitate clinical coagulation management with appropriate pediatric normal ranges, avoiding the application of extrapolated adult data to children. IMPLICATIONS: Sonoclot variables are presented for 95 healthy pediatric surgical patients in four age groups, with small differences found in the Sonoclot (Sienco, Inc., Morrison, CO) activated clotting time between two groups and no significant differences in three other variables among groups.

The effects of intentional hyperthermia on the Thrombelastograph and the Sonoclot analyser.

The effect of whole-body hyperthermia (WBH) on viscoelastic properties of whole blood, as measured by the thrombelastogram (TEG) and Sonoclot analyser, was investigated in 10 patients undergoing WBH-carboplastin therapy for metastatic disease. Blood was taken from an existing central line at baseline (37 degrees C), during warming (39 and 41 degrees C) and cooling (39 and 37 degrees C). Sonoclot and TEG samples were analysed simultaneously at 37 degrees C and at the patient's temperature with a temperature-compensated unit, except at 41 degrees C for the Sonoclot (maximum temperature adjustment of 40 degrees C). TEG measurements included R time (time to initial fibrin formation [mm]), K time (mm) and alpha angle (degrees) (both reflecting fibrinogen-platelet interaction), maximum amplitude (representing qualitative platelet function [mm]) and per cent fibrinolysis at 30 and 60 min. The Sonoclot ACT (SonACT-secs), initial rate of clot formation (%), time to peak amplitude (min) and peak amplitude of the Sonoclot signature (mm) were recorded. Decreased R time of the TEG compared to a marginally elevated baseline was found at all times during warming and cooling (p < 0.05). The K time was decreased at 41 degrees C compared to a normal baseline (p < 0.05). The SonACT was decreased (from an elevated baseline) at all other times, without differences in measures at patient temperature versus 37 degrees C (p < 0.05). The data suggest acceleration of fibrin formation during WBH to 41 degrees C in patients with malignancy. Implications for defining thromboembolic risk require further investigation.

Thromboelastography with heparinase in orthotopic liver transplantation.

OBJECTIVE: To investigate the role of heparin in the postreperfusion coagulopathy during liver transplantation with heparinase-guided thromboelastography. DESIGN: A prospective, interventional study. SETTING: A university-affiliated hospital. PARTICIPANTS: Twenty-six patients undergoing orthotopic liver transplantation (OLT). INTERVENTIONS: Blood drawn at five intervals for thromboelastography assessment with native (12 patients) or celite blood (14 patients) compared with simultaneous thromboelastography traces with added heparinase. MAIN RESULTS: In the native samples, the prolonged R (reaction) and K (coagulation) time and decreased alpha angle were corrected in heparinase thromboelastograph traces immediately before reperfusion and 10 minutes postreperfusion. In the celite-accelerated samples, the heparinase traces showed correction of the R and K times and alpha angle only at the 10-minute postreperfusion stage. In seven patients who had thromboelastography performed after protamine administration, there were no differences between celite and heparinase-celite traces. CONCLUSIONS: Heparinase-treated thromboelastography offered compelling evidence for the presence of heparin-like activity after liver graft reperfusion. The objective evidence provided by this modification of thromboelastography-guided protamine administration and was useful in identifying one of the many potential causes of postreperfusion bleeding in patients undergoing OLT.

Massive macroglossia after posterior fossa surgery in the prone position.

We describe an unusual case of severe postoperative macroglossia after posterior fossa surgery in the prone position, and review potential causative factors and prophylactic measures that may alleviate this serious complication.

Perioperative hypercoagulability in uremic patients: a viscoelastic study.

STUDY OBJECTIVE: To examine whole blood coagulation in uremic patients presenting for surgery with the thromboelastogram and the Sonoclot analyzer. DESIGN: Prospective, observational study. SETTING: Operating rooms of a university-affiliated hospital. PATIENTS: 30 ASA physical status II and III patients with chronic renal failure, and 30 age-matched and gender-matched patients with normal renal function, presenting for elective surgery. INTERVENTIONS: Blood sampling for thromboelastograph and Sonoclot analysis immediately after anesthetic induction, prior to surgical incision. MEASUREMENTS AND MAIN RESULTS: Thromboelastographic indices of coagulation, reflecting coagulation factor function (R time), fibrinogen-platelet interaction (K time and alpha angle), and qualitative platelet function (maximum amplitude) were hypercoagulable in the uremic group compared with the control group (p < 0.05). Fibrinolysis (%) was decreased in the uremic group (p < 0.05). Fibrin formation (initial slope) and platelet function (time to peak) of the Sonoclot trace also were hypercoagulable in the uremic group (p < 0.05). CONCLUSIONS: The high incidence of arteriovenous graft and fistulae thromboses in uremic patients belies in vitro laboratory evidence of platelet dysfunction. We have demonstrated perioperative hypercoagulability in uremic patients with viscoelastic measures of whole blood coagulation. These data suggest that traditional concern for coagulopathy and platelet dysfunction in uremic patients may require re-assessment in light of this "pro-thrombotic" state.