Identifying workflow disruptions in the cardiovascular operating room.

The objectives of this study were to identify the frequency and nature of flow disruptions in the operating room with respect to three cardiac surgical team members: anaesthetists; circulating nurses; and perfusionists. Data collected from 15 cases and coded using a human factors taxonomy identified 878 disruptions. Significant differences were identified in frequency relative to discipline type. Circulating nurses experienced more coordination disruptions (χ(2) (2, N = 110) = 7.136, p < 0.028) and interruptions (χ(2) (2, N = 427) = 29.743, p = 0.001) than anaesthetists and perfusionists, whereas anaesthetists and perfusionists experienced more layout issues than circulating nurses (χ(2) (2, N = 153) = 48.558, p = 0.001). Time to resolve disruptions also varied among disciplines (λ (12, 878) = 5.186, p = 0.000). Although most investigations take a one-size fits all approach in addressing disruptions to flow, this study demonstrates that targeted interventions must focus on differences with respect to individual role.

Endothelin-1 during and after cardiopulmonary bypass: association to graft sensitivity and postoperative recovery.

OBJECTIVE: Our objectives are 2-fold: (1) to serially measure the release of endothelin and graft-conduit endothelin sensitivity during and after coronary artery bypass grafting and (2) to define potential relationships of changes in endothelin levels to perioperative parameters. METHODS: Endothelin plasma content was measured in patients (n = 105) undergoing bypass grafting from select vascular compartments before operations and at specific intervals up to 24 hours postoperatively. Endothelin sensitivity was determined in isolated internal thoracic artery segments. RESULTS: Systemic arterial and pulmonary arterial endothelin levels were increased by approximately 50% immediately after bypass grafting and increased by another 85% during the first 24 hours postoperatively. Endothelin levels were highest in patients with prolonged ventilatory requirements and extended stays in the intensive care unit (10.2 +/- 0.8 vs 13.2 +/- 1.1 fmol/mL, P =.02, and 9.8 +/- 0.7 vs 13.9 +/- 1.2 fmol/mL, P =.01, respectively. Endothelin sensitivity of the internal thoracic artery was increased in patients requiring prolonged vasodilator support with nitroglycerin. CONCLUSIONS: Systemic and pulmonary arterial endothelin levels remained increased for at least 24 hours postoperatively. Prolonged pharmacologic management and increased intensive care unit stay were associated with increased systemic endothelin release and heightened graft-conduit sensitivity to endothelin.

Coronary artery bypass grafting with and without cardiopulmonary bypass: a comparison analysis.

Coronary artery bypass grafting (CABG) using stabilization devices in place of the heart-lung machine is being performed on a wide range of patients. This study retrospectively compared the performance of off-pump coronary artery grafting bypass (OPCAB) with conventional bypass patients over the same 6-month period at The Medical University of South Carolina. Data were collected and compared from the National Cardiac Database of the Society of Thoracic Surgeons (STS). Parameters studied included age, gender, left ventricular ejection fraction (LVEF), previous myocardial infarction (MI), disease severity, number of grafts, complications, blood usage, ventilation times, operating room (OR) time, and hospital length of stay (LOS). There were no significant difference between the patient groups with regard to age, gender, LVEF, previous MI, predicted mortality, and LOS. Operative mortality was also similar in the two groups: conventional bypass 4/117 (3%) and OPCAB 2/86 (2%). The conventional bypass patients (CPB) had significantly (p < 0.05) more diseased vessels (2.9 vs. 2.6) and distal grafts (4.1 vs. 2.7), as compared to the OPCAB group. OPCAB procedures resulted in significantly (p < 0.05) lower mean OR time (365 min vs. 406 min) and reduced mean postoperative ventilation hours (3.4 vs. 8.3 hours), as compared to conventional bypass. There were significantly (p < 0.05) fewer blood transfusions in the OPCAB group (1.1 units vs. 2.4 units), and the percentage of patients transfused blood was significantly less (34.9% vs. 57.3%). Nine out of 95 (9.5%) of patients who presented for OPCAB were converted to conventional bypass. Although there may be potential benefits to OPCAB, further studies must be directed at determining those patients who would benefit most from CABG using the off-pump technique.

Multicenter trial of prolonged infusions of rocuronium bromide in critically ill patients: effects of multiple organ failure.

BACKGROUND: This study was done to determine the safety, efficacy, dosing requirements, and spontaneous recovery profiles of prolonged infusions of rocuronium bromide in the critically ill. METHODS: This multicenter, prospective, nonrandomized, open label trial enrolled 32 patients at two university-based medical centers. Patients who were determined to require neuromuscular blockade for at least 24 hours received a bolus of 0.6 mg/kg of rocuronium. After subsequent recovery of two responses (T2) to the TOF stimulation, an infusion of rocuronium was begun at 10 microg/kg/min and continued for 24 to 120 hours as required by the patients' clinical status. RESULTS: Patients were divided into multiple organ failure (MOF) and non-multiple organ failure (non-MOF) groups on enrollment. The mean infusion rates for the MOF and non-MOF groups were 0.2 and 0.5 mg/kg/hour, respectively. CONCLUSION: The mean infusion rate of rocuronium that provides approximately 90% blockade is less for critically ill patients with MOF. Spontaneous recovery was prolonged in patients with MOF.

Temporal synthesis and release of endothelin within the systemic and myocardial circulation during and after cardiopulmonary bypass: relation to postoperative recovery.

OBJECTIVE: To determine endothelin levels in arterial, pulmonary, and myocardial vascular compartments in patients undergoing coronary artery bypass graft surgery and to examine the influence of endothelin on postoperative recovery. DESIGN: Prospective, clinical study. SETTING: University hospital. PARTICIPANTS: Fifty patients undergoing elective coronary artery bypass graft surgery. INTERVENTIONS: Endothelin plasma content (fmol/mL) was measured in 50 patients undergoing coronary revascularization from various vascular compartments before surgery and at specific intervals up to 24 hours postoperatively. MEASUREMENTS AND MAIN RESULTS: Myocardial endothelin gradient (coronary sinus - aorta) was calculated before cardiopulmonary bypass (CPB), at release of the aortic cross-clamp, immediately after CPB, and 0.5 hour after CPB. The requirement for inotropic therapy and duration of patient stay in the intensive care unit were determined. Systemic and pulmonary endothelin levels were increased by >80% immediately after CPB when compared with preoperative values and increased again by approximately 60% during the first 24 hours postoperatively (p < 0.05). The myocardial endothelin gradient was reversed after CPB, indicating myocardial production of endothelin (pre-CPB, -0.72+/-0.39 fmol/mL v 0.5 hour post-CPB, 0.60+/-0.49 fmol/mL; p < 0.05). Longer intensive care unit times (>28 hours) were associated with higher systemic endothelin levels when compared with shorter times (<18 hours) (16.30+/-1.33 fmol/mL v 9.81+/-1.67 fmol/mL; p < 0.05). Patients with higher endothelin levels 6 hours postoperatively had greater inotropic requirements during the intensive care unit period. CONCLUSION: Endothelin levels after CPB remained persistently increased for at least 24 hours after surgery and were associated with increased myocardial production of endothelin. These results suggest that the increased endothelin observed in the early postoperative period may contribute to a complex recovery from coronary artery bypass graft surgery.

Magnesium supplementation in the prevention of arrhythmias in pediatric patients undergoing surgery for congenital heart defects.

BACKGROUND: The efficacy of magnesium in the prevention of arrhythmias in pediatric patients after heart surgery remains unknown. Therefore we prospectively examined the effect of magnesium treatment on the incidence of postoperative arrhythmias in pediatric patients undergoing surgical repair of congenital heart defects. METHODS AND RESULTS: Twenty-eight pediatric patients undergoing heart surgery with cardiopulmonary bypass were prospectively, randomly assigned in a double-blind fashion to receive intravenous magnesium (magnesium group, n = 13; 30 mg/kg) or saline (placebo group, n = 15) immediately after cessation of cardiopulmonary bypass. Magnesium, potassium, and calcium levels were measured at defined intervals during surgery and 24 hours after surgery. Continuous electrocardiographic documentation by Holter monitor was performed for 24 hours after surgery. Magnesium levels were significantly decreased below the normal reference range for patients in the placebo group compared with the magnesium group on arrival in the intensive care unit and for 20 hours after surgery. Magnesium levels remained in the normal range for patients in the magnesium group after magnesium supplementation. In 4 patients in the placebo group (27%), junctional ectopic tachycardia developed within the initial 20 hours in the intensive care unit. No junctional ectopic tachycardia was observed in the magnesium group (P =.026). CONCLUSIONS: Although this study was originally targeted to include 100 patients, the protocol was terminated because of the unacceptable incidence of hemodynamically significant junctional ectopic tachycardia that was present in the placebo group. Thus low magnesium levels in pediatric patients undergoing heart surgery are associated with an increased incidence of junctional ectopic tachycardia in the immediate postoperative period.

Preliminary report on high thoracic epidural analgesia: relationship between its therapeutic effects and myocardial blood flow as assessed by stress thallium distribution.

OBJECTIVES: To extend the duration of high thoracic epidural analgesia (HTEA) treatment compared with the authors' previous studies, to test the hypothesis that the mechanism by which HTEA reduces angina during long-term treatment includes an improvement in myocardial blood flow distribution and a reduction in stress-induced ischemia, and to show that new myocardial infarctions are not masked or missed in patients receiving HTEA. DESIGN: Prospective consecutive study. SETTING: Department of Veteran's Affairs medical center and university-affiliated hospital. PARTICIPANTS: Six consenting adult patients. INTERVENTIONS: Patients were evaluated before HTEA catheter insertion and >2 months after HTEA catheter insertion with stress thallium tests. MEASUREMENTS AND MAIN RESULTS: Two of 6 patients had improvement but not resolution of stress-induced ischemia at 8 and 12 months. The remaining 4 patients had no change in stress-induced ischemia. None of the 6 patients had any new areas of ischemia or infarction as determined by stress thallium tests. CONCLUSIONS: The authors previously showed that HTEA is safe and effective in relieving refractory angina pectoris. The current study shows that this therapeutic effect persists and does not appear to be related to a change in myocardial blood flow; rather the improvement in symptoms probably results, in part, from an anesthetic effect. HTEA does not mask the development of new myocardial infarctions.

Continuous infusions of lorazepam, midazolam, and propofol for sedation of the critically ill surgery trauma patient: a prospective, randomized comparison.

OBJECTIVE: To compare the efficacy, safety, and cost of continuous infusions of lorazepam, midazolam, and propofol in a critically ill trauma/surgery patient population. DESIGN: A prospective, randomized, nonblinded, single center. SETTING: A 16-bed intensive care unit. PATIENTS: A total of 30 ventilated patients who were 18-70 yrs of age and required pharmacologic sedation. Patients with renal and/or liver failure, a history of alcohol abuse, a head injury, or in a coma were excluded. INTERVENTIONS: Patients were randomized by block design to receive lorazepam, midazolam, or propofol. Initial boluses and infusion rates were as follows: lorazepam 0.05 mg/kg, then 0.007 mg/kg/hr; midazolam 0.05 mg/kg, then 0.003 mg/kg/hr; and propofol 0.25 mg/kg, then 0.06 mg/kg/hr. Sedation was assessed and agents titrated every 5-10 mins to achieve > or =2 and <5 on the modified Ramsay scale. Once adequate response was achieved, agents were titrated to maintain the desired level of sedation. MEASUREMENTS AND MAIN RESULTS: Maintenance doses of lorazepam 0.02+/-0.01 mg/kg/hr, midazolam 0.04+/-0.03 mg/kg/hr, and propofol 2.0+/-1.5 mg/kg/hr achieved the desired level of sedation 68%, 79%, and 62% of the time, respectively. Oversedation occurred most often with lorazepam, compared with midazolam and propofol, at 14%, 6%, and 7% of the assessment times, respectively. Undersedation occurred most frequently with propofol compared with lorazepam and midazolam, at 31%, 18%, and 16% of the assessment times, respectively. The mean number of dosage changes per day was 7.8+/-4.3 for lorazepam, 4.4+/-2.9 for midazolam, and 5.6+/-6.0 for propofol (p = .91). Sedation costs per patient day (mean +/- SD) were $48+/-$76 (lorazepam), $182+/-$98 (midazolam), and $273+/-$200 (propofol) (p = .005). The potential savings, if all study patients had received lorazepam, is $14,208 compared with $8,808 if all received midazolam. CONCLUSIONS: The data suggest that lorazepam appears to be a cost-effective choice for sedation; however, oversedation may be problematic. Midazolam is the most titratable drug in our population, avoiding excessive oversedation or undersedation. Trauma patients may respond inadequately to propofol even at higher doses. Lorazepam may be the sedative of choice in critically ill trauma/surgery patients.

Postdural puncture headache in paediatric oncology patients.

PURPOSE: Previous studies have not determined the correlation between dural puncture and postural headache in paediatric patients. Furthermore, no studies have evaluated the correlation between atypical headache and dural puncture in the paediatric population. Therefore, we prospectively analyzed the incidence of typical postdural puncture headache (PDPHA) and atypical headache in paediatric oncology patients following dural puncture. METHODS: The study population consisted of 66 paediatric patients undergoing 128 consecutive procedures, including 99 lumbar punctures and 29 bone marrow aspirations without concomitant lumbar puncture. Patients were prospectively randomized into four groups: Group I, preteens (< 13 yr) undergoing lumbar puncture, Group II, adolescents (13-21 yr) undergoing lumbar puncture, Group III, preteens undergoing bone marrow aspiration, and Group IV, adolescents undergoing bone marrow aspiration. The presence and description of headache was documented immediately after dural puncture or bone marrow aspiration, and on post-procedure days # 1, 3 and 5 by personnel blinded to the type of procedure. RESULTS: There was an increase in the incidence of headache (9.1%) after lumbar puncture in patients < 21 yr relative to patients undergoing bone marrow aspiration (P < 0.05). No difference was found between the incidence of typical PDPHA after dural puncture in preteens and adolescents. There was also no difference in the incidence of atypical headache after dural puncture or after bone marrow aspiration among preteens and adolescents. CONCLUSIONS: Paediatric patients experience an increased incidence of typical postdural puncture headache after dural puncture compared with age-matched patients undergoing bone marrow aspiration only. Atypical headache is relatively common in the paediatric population after dural puncture or bone marrow aspiration.

Nondepolarizing neuromuscular blocking drugs in the intensive care unit: a clinical review.

BACKGROUND: The use of nondepolarizing neuromuscular blocking drugs (NDNMBDs) via continuous infusion in the intensive care unit (ICU) is gaining in popularity. Several new NDNMBDs have been developed recently; these drugs vary in their elimination, metabolism, and half-lives. METHODS: A review of the recent English language literature was done, with those articles relevant to the ICU being incorporated into this paper. RESULTS: The six most frequently used NDNMBDs, consisting of atracurium, cisatracurium, doxacurlum, pancuronium, rocuronium, and vecuronium, were reviewed. The neuromuscular junction and impulse transmission, clinical monitoring, clinical pharmacology, the elimination and metabolism, the adverse reactions, and the drug interactions of these NDNMBDs are reviewed. CONCLUSIONS: The use of NDNMBDs is progressively increasing in ICUs. Proper understanding of normal neuromuscular physiology, clinical pharmacology, and drug interactions is essential to optimize patient care and to minimize the risk of adverse reactions.

Treatment of medically and surgically refractory angina pectoris with high thoracic epidural analgesia: initial clinical experience.

Surgical sympathectomy can relieve symptoms of angina in patients with refractory angina. However, in these high-risk patients this thoracic surgery may result in significant morbidity and mortality rates. Similar sympathetic blockade can now be produced with high thoracic epidural analgesia (HTEA). From September 1995 to August 1996, we treated 10 consecutive patients with HTEA. These eight men and two women, aged 58 +/- 5 years, with extensive three-vessel coronary disease and ejection fractions of 40% +/- 5%, had New York Heart Association (NYHA) class IV angina despite medical therapy, including nitrates, beta-blockade, calcium channel blockade, and narcotics. HTEA was performed at the T1 through T4 levels with a catheter placed either percutaneously or surgically, with radiographic confirmation of catheter placement with an epidurogram or computed tomography scan. Bupivacaine (0.25% to 0.5%), an amide local anesthetic, was given as a bolus through the epidural catheter and then maintained either as a continuous infusion or an intermittent rebolus. The epidural catheter remained in place for 7 days in four patients, 14 days in three patients, and > or =90 days in three patients. Before consideration for HTEA, each patient was deemed unsuitable for or refused coronary bypass surgery and percutaneous coronary angioplasty and had NYHA class IV symptoms of angina. Seven of 10 patients required intravenous nitroglycerin and heparin and were unable to be discharged from the intensive care unit because of anginal symptoms. Two of these seven patients also required an intraaortic balloon pump for symptom control. After HTEA, all 10 patients had improved symptoms, with five patients improving to NYHA class II symptoms and five improving to NYHA class III. All seven patients receiving intravenous nitroglycerin, heparin, or intraaortic balloon pump support had these modalities discontinued. Six of these seven patients were subsequently discharged from the hospital. One patient died from a non-HTEA related cause. There were no HTEA-related deaths. There were three catheter-related complications necessitating catheter removal during 12 months of HTEA use. Local infection developed in one patient, one had catheter occlusion caused by fibrosis, and one patient had chronic back pain exacerbation from a paraspinous muscle spasm. No patient had a myocardial infarction or a significant arrhythmia. In patients with otherwise intractable angina pectoris, HTEA is an effective modality that produces symptomatic relief of angina pectoris and allows increased activity level.

Abdominal compartment syndrome.

PURPOSE: Two cases of abdominal compartment syndrome are described and the pathophysiology associated with it is reviewed. CLINICAL FEATURES: The first patient was a 46-yr-old man who sustained extensive blunt abdominal injuries following a fall. The second was a 54-yr-old man involved in a motor vehicle accident with blunt abdominal trauma. In both cases, the patients developed an extremely tense abdomen, increasing peak inspiratory pressures, hypercarbia and oliguria. Both demonstrated improvement in cardiac performance and ventilatory variables following an emergency decompressive celiotomy. CONCLUSION: Abdominal compartment syndrome results in impairment of organ function secondary to increased intraabdominal pressure. These patients require emergency decompressive celiotomy to relieve the symptoms. However, the incidence of intractable asystole and hypotension during this procedure is high and vigilance must be maintained during the release of the increased intraabdominal pressure.

Tranexamic acid reduces bleeding after cardiopulmonary bypass when compared to epsilon aminocaproic acid and placebo.

UNLABELLED: Perioperative bleeding following coronary artery bypass grafting (CABG) is associated with increased blood product usage. Although aprotonin is effective in reducing perioperative blood loss, excessive cost prohibits routine utilization. Epsilon aminocaproic acid (EACA) and tranexamic acid (TA) are inexpensive antifibrinolytic agents, which, when given prophylactically, may reduce blood loss. The present study was undertaken to compare the efficacy of TA and EACA in reducing perioperative blood loss. METHODS: The study population consisted of first-time CABG patients. Patients were allocated in a prospective double-blind fashion: (1) group EACA (loading dose 15 mg/kg, continuous infusion 10 mg/kg per hour for 6 hours, N = 20); (2) group TA (loading dose 15 mg/kg, continuous infusion 1 mg/kg per hour for 6 hours, N = 20); (3) control group (infusion of normal saline for 6 hours, N = 19). RESULTS: Treatment groups were similar preoperatively. No significant difference in intraoperative blood loss or perioperative use of blood products was noted. D-dimer concentration was elevated in the control group compared to the EACA and TA groups (p < 0.05). Group TA had less postoperative blood loss than the EACA and control groups at 6 and 12 hours postoperatively (p < 0.05). TA had reduced total blood loss (600 +/- 49 mL) postoperatively compared to EACA (961 +/- 148 mL) and control (1060 +/- 127 mL, p < 0.05). CONCLUSION: TA and EACA effectively inhibited fibrinolytic activity intraoperatively and throughout the first 24 hours postoperatively. TA was more effective in reducing blood loss postoperatively following CABG. This suggests that TA may be beneficial as an effective and inexpensive antifibrinolytic in first-time CABG patients.

The effect of bupivacaine skull block on the hemodynamic response to craniotomy.

The placement of pointed cranial pins into the periosteum is a recognized acute noxious stimulation during intracranial surgery which can result in sudden increases in blood pressure and heart rate, causing increases in intracranial pressure. A skull block (blockade of the nerves that innervate the scalp, including the greater and lesser occipital nerves, the supraorbital and supratrochlear nerves, the auriculotemporal nerves, and the greater auricular nerves) may be effective in reducing hypertension and tachycardia. Twenty-one patients were allocated in a prospective, double-blind fashion to a control group or a bupivacaine group. After a standardized induction and 5 min prior to head pinning, a skull block was performed. Patients in the control group received a skull block of normal saline, while the bupivacaine group received a skull block with 0.5% bupivacaine. Systolic (SAP), diastolic (DAP), mean arterial pressure (MAP), heart rate (HR), and end-tidal isoflurane were recorded at the following times: 5 min after the induction of anesthesia, during performance of the skull block, during head pinning, and 5 min after head pinning. Significant increases in SAP of 40 +/- 6 mm Hg, DAP of 30 +/- 5 mm Hg, MAP of 32 +/- 6 mm Hg, and HR of 22 +/- 5 bpm occurred during head pinning in the control group, while remaining unchanged in the bupivacaine group. These results demonstrate that a skull block using 0.5% bupivacaine successfully blunts the hemodynamic response to head pinning.

The effects of desmopressin and 6% hydroxyethyl starch on factor VIII:C.

In moderate doses of 20 mL/kg (1.2 g/kg), hydroxyethyl starch (HES) 6% decreases factor VIII:C activity. Desmopressin (DDAVP) increases circulating levels of factor VIII:C by stimulating the release of factor VIII:C from peripheral storage sites. The objective of this study was to monitor the changes in factor VIII:C associated with sequential HES and DDAVP administration. Thirty patients undergoing surgical procedures with a predicted blood loss of less than 750 mL were enrolled. After induction of anesthesia, HES was administered, 20 mL/kg, to a maximum of 1500 mL, at a rate to meet intraoperative fluid requirements. Patients then randomly received either a 10-mL solution containing 0.3 microgram/kg of DDAVP (Group 1) or 10 mL of normal saline (Group 2). After HES administration, factor VIII:C levels decreased significantly, to 69% of baseline, in both groups. After study drug administration, factor VIII:C in Group 1 increased significantly to 135% of baseline at 30 min and 115% of baseline at 60 min while in Group 2 average factor VIII:C levels remained below baseline at 30 and 60 min. DDAVP produced an increase in factor VIII:C activity despite HES administration and should be considered a treatment option for the mild coagulopathy infrequently associated with HES administration.

Intravenous sedation for placement of automatic implantable cardioverter-defibrillators.

OBJECTIVE: To evaluate a change in anesthetic technique for transvenous placement of the automatic implantable cardioverter-defibrillator (ICD). DESIGN: Retrospective study. SETTING: A university hospital. PARTICIPANTS: Twenty-eight patients who underwent placement of ICDs. INTERVENTIONS: Thirteen patients had the ICD placed via the transvenous approach with general anesthesia (group GA). Fifteen patients had the ICD placed via the transvenous approach with intravenous sedation (group IV). MEASUREMENTS AND MAIN RESULTS: Intraoperative systolic and diastolic blood pressures were significantly higher in group IV compared with group GA. The ICD was successfully placed in all patients in both groups. There were no intraoperative complications noted in either group during induction of fibrillation and defibrillation, and there was no recall by any patient in either group. The average hospital stay was significantly less in group IV (1.8 days) compared with group GA (3.4 days). CONCLUSIONS: Intravenous sedation for the placement of ICDs is a safe and effective technique. Patients who had their ICD placed while receiving intravenous sedation experienced higher intraoperative blood pressures and were discharged from the hospital earlier than those patients who received general anesthesia.

Positioning a right atrial air aspiration catheter using transesophageal echocardiography.

The occurrence of venous air embolism (VAE) during neurosurgery in the sitting position is well documented. The optimal position of an air aspiration catheter appears to be with the catheter tip at the junction of the right atrium and superior vena cava (SVC). A number of localization techniques have been described, with the electrocardiographic guided technique being the most commonly employed. This case report describes the use of transesophageal echocardiography (TEE) for the precise and timely placement of a right atrial-SVC air aspiration catheter.

A randomized double-blind trial of chloral hydrate/hydroxyzine versus midazolam/acetaminophen in the sedation of pediatric dental outpatients.

The purpose of this study was to evaluate in a randomized, double-blinded fashion the sedative and behavioral responses of children undergoing pediatric dental procedures as outpatients and who had received a combination of either oral chloral hydrate 50 mg/kg, not to exceed 1 gm, with hydroxyzine 25 mg (Group 1); or oral midazolam 0.5 mg/kg with acetaminophen elixir 10 mg/kg (Group 2). The children were rated according to sleep, movement, crying and overall behavior at preselected intervals that included presedation, introduction to the operating suite, injection, and overall behavior. There were no statistical differences between the two groups in regards to age, weight, length of procedure, or sex. Group 1 was more asleep in the later time intervals (P < 0.05). Their were no statistically significant differences between the groups in relation to the overall evaluation for the procedure. In conclusion, midazolam/acetaminophen is as effective as chloral hydrate/hydroxyzine in the sedation of young children undergoing outpatient dental procedures.