James M. Berry

The antiemetic effect of lorazepam after outpatient strabismus surgery in children

The high incidence of postoperative emesis after strabismus surgery in pediatric outpatients can be reduced by the prophylactic administration of droperidol 75 micrograms/kg intravenously. However, this may be associated with profound sedation, delayed discharge, dysphoria, agitation, and extrapyramidal symptoms in this population. Because lorazepam used as an antiemetic in children during chemotherapy decreased the incidence of nausea and vomiting, we compared the antiemetic effects of lorazepam and droperidol in a randomized, double-blind, placebo-controlled study of 129 healthy children undergoing surgical correction of strabismus. The children, aged 1-13 yr, were randomly allocated into three groups. The children in group 1 received droperidol 75 micrograms/kg intravenously; those in group 2 received lorazepam 10 micrograms/kg intravenously; and those in group 3 received placebo. Anesthesia consisted of halothane, nitrous oxide in oxygen, and atracurium. Study drugs were administered intravenously after induction of anesthesia but before surgery. In children 3-13 yr old, administration of either lorazepam or droperidol was associated with a lower (P < 0.024) incidence of postoperative vomiting. There was no difference between the antiemetic effect of lorazepam and that of droperidol. The incidence of postoperative agitation was greater in the droperidol group (P < 0.001) than in the lorazepam and placebo groups. Postdischarge vomiting was less (P < 0.009) in children younger than 3 yr of age. Lorazepam, similar to droperidol, has an antiemetic effect in outpatient children 3-13 yr old undergoing strabismus correction, but it is associated with less postoperative agitation than is droperidol.

Body Morphology and the Speed of Cutaneous Rewarming

BackgroundInfants and children cool quickly because their surface area (and therefore heat loss) is large compared with their metabolic rate, which is mostly a function of body mass. Rewarming rate is a function of cutaneous heat transfer plus metabolic heat production divided by body mass. Therefore, the authors tested the hypothesis that the rate of forced-air rewarming is inversely related to body size. MethodsIsoflurane, nitrous oxide, and fentanyl anesthesia were administered to infants, children, and adults scheduled to undergo hypothermic neurosurgery. All fluids were warmed to 37°C and ambient temperature was maintained near 21°C. Patients were covered with a full-body, forced-air cover of the appropriate size. The heater was set to low or ambient temperature to reduce core temperature to 34°C in time for dural opening. Blower temperature was then adjusted to maintain core temperature at 34°C for 1 h. Subsequently, the forced-air heater temperature was set to high (≈ 43°C). Rewarming continued for the duration of surgery and postoperatively until core temperature exceeded 36.5°C. The rewarming rate in individual patients was determined by linear regression. ResultsRewarming rates were highly linear over time, with correlations coefficients (r2) averaging 0.98 ± 0.02. There was a linear relation between rewarming rate (°C/h) and body surface area (BSA; m2): Rate (°C/h) = −0.59 · BSA (m2) + 1.9, r2 = 0.74. Halving BSA thus nearly doubled the rewarming rate. ConclusionsInfants and children rewarm two to three times faster than adults, thus rapidly recovering from accidental or therapeutic hypothermia.

Etomidate myoclonus and the open globe

Etomidate is a rapid-acting hypnotic, valued for its minimal respiratory and cardiovascular depression in comparison with thiopental. Known side effects include pain on injection, postoperative nausea and vomiting, electroencephalic activation, adrenal suppression, and myoclonus (1,2). Patients who have sustained open eye injuries are at risk of exacerbation of damage to the injured eye on induction of general anesthesia. Coughing, straining, hypoxia, and airway obstruction can rapidly increase intraocular pressure (IOP) (3-5). The combination of an open eye injury, a full stomach, and limited cardiovascular reserves produces a uniquely treacherous combination of circumstances for the anesthesiologist.

The successful use of regional anesthesia to prevent involuntary movements in a patient undergoing awake craniotomy

IMPLICATIONS The authors demonstrate that the combination of single and continuous peripheral nerve blocks allows the control of involuntary movements in patients undergoing awake craniotomy.

A cost-construction model to assess the total cost of an anesthesiology residency program

BACKGROUND Although the total costs of graduate medical education are difficult to quantify, this information may be of great importance for health policy and planning over the next decade. This study describes the total costs associated with the residency program at the University of Texas--Houston Department of Anesthesiology during the 1996-1997 academic year. METHODS The authors used cost-construction methodology, which computes the cost of teaching from information on program description, resident enrollment, faculty and resident salaries and benefits, and overhead. Surveys of faculty and residents were conducted to determine the time spent in teaching activities; access to institutional and departmental financial records was obtained to quantify associated costs. The model was then developed and examined for a range of assumptions concerning resident productivity, replacement costs, and the cost allocation of activities jointly producing clinical care and education. RESULTS The cost of resident training (cost of didactic teaching, direct clinical supervision, teaching-related preparation and administration, plus the support of the teaching program) was estimated at

Residual Neuromuscular Blockade at Extubation: A Randomized Comparison of Sugammadex and Neostigmine Reversal of Rocuronium-Induced Blockade in Patients Undergoing Abdominal Surgery

75,070 per resident per year. This cost was less than the estimated replacement value of the teaching and clinical services provided by residents,

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

103,436 per resident per year. Sensitivity analysis, with different assumptions regarding resident replacement cost and reimbursement rates, varied the cost estimates but generally identified the anesthesiology residency program as a financial asset. CONCLUSIONS In most scenarios, the value of the teaching and clinical services provided by residents exceeded the cost of the resources used in the educational program.

Comets and life

Background: Residual neuromuscular blockade (NMB) is associated with increased risk of post-operative critical respiratory events. We compared incidence of residual NMB at tracheal extubation after reversal of rocuroniuminduced NMB with sugammadex versus neostigmine. Methods: Adult patients of American Society of Anesthesiologists Class 1-3, scheduled to undergo open abdominal surgery were included. Patients were randomized to receive sugammadex 4.0 mg/kg at ≥1-2 posttetanic counts after last rocuronium dose, or neostigmine 50mg/kg + glycopyrrolate 10mg/kg, according to usual care practices at each institution. Neuromuscular function was assessed using TOF-Watch® SX. Anesthesiologists were blinded to the TOF-Watch recording, except to ask the TOF-Watch operator whether ≥1 PTC had been reached before administering reversal. Use of a peripheral nerve stimulator was permitted. Clinical criteria defined by the institution were used to determine when to perform extubation. Primary efficacy variable was incidence of residual NMB (train-of-four [TOF] ratio <0.9) at extubation. Safety parameters were assessed by a blinded safety assessor. Results: The intent-to-treat group comprised 97 patients (sugammadex, n=51; neostigmine, n=46). Among patients with valid TOF data, a TOF ratio of ≥0.9 was reached at or before extubation in 48 of 50 (96.0%) sugammadex and 17 of 43 (39.5%) neostigmine patients (P<0.0001). One sugammadex (2.0%) and 15 neostigmine patients (34.9%) were extubated at TOF ratios ≤0.7. Median (95% CI) time from study drug administration to recovery to a TOF ratio ≥0.9 was 2.0 (1.8-2.5) minutes for sugammadex (n=49) versus 8.0 (3.8-16.5) minutes for neostigmine (n=18) (P<0.0001). Safety was comparable between groups, with no clinical evidence of recurrence of NMB. Conclusions: Significantly more sugammadex-treated patients recovered to a TOF ratio ≥0.9 at extubation and did so significantly faster than neostigmine-treated patients. This study confirms that sugammadex is more effective than neostigmine in reducing potential for residual blockade in the absence of objective NMB monitoring.

Sudden asystole during craniotomy: unrecognized phenytoin toxicity.

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 patients 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.

Recognizing changes in patient condition on a postsurgical unit.

Some of the chemical species which have been detected in comets include H2O, HCN, CH3CN, CO, CO2, NH3, CS, C2 and C3. All of these have also been detected in the interstellar medium, indicating a probable relationship between interstellar dust and gas clouds and comets. Laboratory experiments carried out with different mixtures of these molecules give rise to the formation of the biochemical compounds which are necessary for life, such as amino acids, purines, pyrimidines, monosaccharides, etc. However, in spite of suggestions to the contrary, the presence of life in comets is unlikely. On the other hand, the capture of cometary matter by the primitive Earth is considered essential for the development of life on this planet. The amount of cometary carbon-containing matter captured by the Earth, as calculated by different authors, is several times larger than the total amount of organic matter present in the biosphere (10(18)g). The major classes of reactions which were probably involved in the formation of key biochemical compounds are discussed. Our tentative conclusions are that: 1) comets played a predominant role in the emergence of life on our planet, and 2) they are the cosmic connection with extraterrestrial life.