Robert F. Brooker

Practice guidelines for perioperative transesophageal echocardiography

P RACTICE Guidelines are systematically developed recommendations that assist the practitioner and the patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open forum commentary, and clinical feasibility data. This update includes data published since the Practice Guidelines for Perioperative Transesophageal Echocardiography were adopted by the ASA and the Society of Cardiovascular Anesthesiologists in 1995 and published in 1996. Methodology

Cardiotomy suction : a major source of brain lipid emboli during cardiopulmonary bypass

BACKGROUND Brain injury remains a significant problem in patients undergoing cardiac surgery assisted by cardiopulmonary bypass (CPB). Autopsy brain specimens of patients after cardiac operations with CPB reveal numerous acellular lipid deposits (10 to 70 microm) in the microvasculature. We hypothesize that these small capillary and arterial dilatations result from a diffuse inflammatory response to CPB or from emboli delivered by the bypass circuit. This study was undertaken to determine which aspect of CPB is most clearly associated with these dilatations. METHODS Thirteen dogs were studied in four groups: group I (n = 3), right-heart CPB; group II (n = 2), lower-extremity CPB; group III (n = 3), hypothermic CPB; and group IV (n = 5), hypothermic CPB with cardiotomy suction. All dogs in all groups were maintained on CPB for 60 minutes and then euthanized. Brain specimens were harvested, fixed in ethanol, embedded in celloidin, and stained with the alkaline phosphate histochemical technique so that dilatations could be counted. RESULTS All dogs completed the protocol. The mean density of dilatations per square centimeter for each group was as follows: group I, 1.77 +/- 0.77; group II, 4.17 +/- 1.65; group III, 4.54 +/- 1.69; and group IV, 46.5 +/- 14.5. In group IV (cardiotomy suction), dilatation density was significantly higher than in group III (hypothermic cardiopulmonary bypass) (p = 0.04) and all other groups (p = 0.04). CONCLUSIONS Blood aspirated from the surgical field and subsequently reinfused into dogs undergoing CPB produces a greater density of small capillary and arterial dilatations than CPB without cardiotomy suction, presumably because of lipid microembolization.

Risk Factors and Solutions for the Development of Neurobehavioral Changes After Coronary Artery Bypass Grafting

BACKGROUND As operative mortality for coronary artery bypass grafting has decreased, greater attention has focused on neurobehavioral complications of coronary artery bypass grafting and cardiopulmonary bypass. METHODS To assess risk factors and to evaluate changes in surgical technique, between 1991 and 1994 we evaluated 395 patients undergoing coronary artery bypass grafting with an 11-part neurobehavioral battery administered preoperatively and at 1 and 6 weeks postoperatively. Patients were instrumented with 5-MHz focused continuous-wave carotid Doppler transducers intraoperatively to estimate cerebral microembolism as an instantaneous perturbation of the velocity signal. Microembolism data were quantitated and compared with surgical technical maneuvers during operation and with neurobehavioral deficit (> or = 20% decline from preoperative performance on two or more neurobehavioral tests) postoperatively. These data and patient demographics were statistically analyzed (chi2, t test) and the results at 2 years (1991 and 1992; group A) were used to influence surgical technique in 1993 and 1994 (group B). RESULTS Significantly associated with new neurobehavioral deficits were increasing patient age (p < 0.05), more than 100 emboli per case (p < 0.04), and palpable aortic plaque (p < 0.02). Group B patients had a significant decline in the neurobehavioral event rate (group A, 69%, 140/203; versus group B, 60%, 115/192; p < 0.05) of postoperative neurobehavioral deficits at 1 week and at 1 month (group A, 29%, 52/180; versus group B, 18%, 35/198; p < 0.01). The stroke rate was less than 2% in both groups (p = not significant). Modifications of surgical technique used in group B patients included increased use of single cross-clamp technique, increased venting of the left ventricle, and application of transesophageal and epiaortic ultrasound scanning to locate and avoid trauma to aortic atherosclerotic plaques. CONCLUSIONS Neurobehavioral changes after coronary artery bypass grafting are common and associated with cerebral microembolization. Surgical technical maneuvers designed to reduce emboli production may improve neurobehavioral outcome.

Feasibility, Accuracy, and Incremental Value of Intraoperative Three-Dimensional Transesophageal Echocardiography in Valve Surgery

In this prospective trial, intraoperative 2-dimensional (2-D) and 3-dimensional (3-D) transesophageal echocardiography (TEE) examinations were performed on 60 consecutive patients undergoing cardiac valve surgery. Both 2-D (including color flow and Doppler data) and 3-D images were reviewed by blinded observers, and major valvular morphologic findings recorded. In vivo morphologic findings were noted by the surgeon and all explanted valves underwent detailed pathologic examination. To test reproducibility, 6 patients also underwent 3-D TEE 1 day before surgery. A total of 132 of 145 attempted acquisitions (91%) were completed with a mean acquisition time of 2.8 +/- 0.2 minutes. Acquisition time was significantly shorter in patients with regular rhythms. Reconstructions were completed in 121 of 132 scans (92%) and there was at least 1 good reconstruction in 56 of 60 patients (93%). Mean reconstruction time was 8.6 +/- 0.7 minutes. Mean effective 3-D time, which was the time taken to complete an acquisition and a clinically interpretable reconstruction, was 12.2 +/- 0.8 minutes. Intraoperative 3-D echocardiography was clinically feasible in 52 patients (87%). Three-D echocardiography detected most of the major valvular morphologic abnormalities, particularly leaflet perforations, fenestrations, and masses, confirmed on pathologic examination. Three-D echocardiography predicted all salient pathologic findings in 47 patients (84%) with good quality images. In addition, in 15 patients (25%), 3-D echocardiography provided new additional information not provided by 2-D echocardiography, and in 1 case, 3-D echocardiographic findings resulted in a surgeons decision to perform valve repair rather than replacement. In several instances, 3-D echocardiography provided complementary morphologic information that explained the mechanism of abnormalities seen on 2-D and color flow imaging. In the reproducibility subset, preoperative and intraoperative 3-D imaging detected a similar number of findings when compared with pathology. Thus, in routine clinical intraoperative settings, 3-dimensional TEE is feasible, accurately predicts valve morphology, and provides additional and complementary valvular morphologic information compared with conventional 2-D TEE, and is probably reproducible.

The importance of the postoperative anesthetic visit : Do repeated visits improve patient satisfaction or physician recognition ?

This study evaluates whether repeated postoperative visits by the anesthesiologist improve patient ability to recall the anesthesiologists name and the patients perception of and satisfaction with anesthesia services.In a randomized, prospective trial, 144 patients with an anticipated postoperative length of stay of at least three days were enrolled in three groups: Group A patients (n = 48) had one postoperative visit, Group B (n = 48) had two postoperative visits, and Group C (n = 48) had three postoperative visits. All postoperative visits were performed by the attending anesthesiologist on consecutive postoperative days. Patients were contacted two days after their last postoperative visit to complete a study questionnaire. Patients were able to recall the anesthesiologists name significantly less frequently than the surgeons name, and there was no difference in name recall among groups. Recall was not affected by patient age, sex, or ASA physical status; the mode of contact (telephone versus personal visit); the anesthesiologists gender; the presence of preoperative medication; or the identity of the preoperative evaluator. Patients could identify the anesthesiologists gender approximately 85% of the time, regardless of group, and were more likely to identify female anesthesiologists (P = 0.026, odds ratio 3.3). Patient evaluation of hospital, surgical, and anesthesia care was favorable in all groups and did not vary with group. Increasing the number of postoperative visits does not improve patient name recognition of the anesthesiologist or increase patient satisfaction with or perception of anesthesia services. (Anesth Analg 1996;83:793-7)

Video as a Patient Teaching Tool: Does It Add to the Preoperative Anesthetic Visit?

M eeting the anesthesiologist is one of the surgical patient’s highest priorities preoperatively (l), and several reports document that this interaction reduces patient anxiety (2-4). High anxiety may be associated with poorer surgical outcome (5), whereas improved patient education is associated with increased patient satisfaction (6) and improved clinical outcome (7). Video instruction may supplement conventional instruction techniques for general medical patients (8) and aid in obtaining informed consent (9). No study has specifically evaluated an instructional video about anesthesia as a tool for educating surgical patients about their upcoming anesthetic and facilitating the anesthesiologist-patient relationship. The hypothesis of this study is that viewing an anesthesia preoperative video will improve patient knowledge and patient perception of the upcoming anesthetic and surgery compared to a standard preoperative interview without video instruction.

Treatment of Hypotension after Hyperbaric Tetracaine Spinal Anesthesia A Randomized, Double-blind, Cross-over Comparison of Phenylephrine and Epinephrine

BACKGROUND Despite many advantages, spinal anesthesia often is followed by undesirable decreases in blood pressure, for which the ideal treatment remains controversial. Because spinal anesthesia-induced sympathectomy and management with a pure alpha-adrenergic agonist can separately lead to bradycardia, the authors hypothesized that epinephrine, a mixed alpha- and beta-adrenergic agonist, would more effectively restore arterial blood pressure and cardiac output after spinal anesthesia than phenylephrine, a pure alpha-adrenergic agonist. METHODS Using a prospective, double-blind, randomized, cross-over study design, 13 patients received sequential infusions of epinephrine and phenylephrine to manage hypotension after hyperbaric tetracaine (10 mg) spinal anesthesia. Blood pressure, heart rate, and stroke volume (measured by Doppler echocardiography using the transmitral time-velocity integral) were recorded at baseline, 5 min after injection of tetracaine, and before and after management of hypotension with epinephrine and phenylephrine. Cardiac output was calculated by multiplying stroke volume x heart rate. RESULTS Five min after placement of a hyperbaric tetracaine spinal anesthesia, significant decrease in systolic (from 143 +/- 6 mmHg to 125 +/- 5 mmHg; P < 0.001), diastolic (from 81 +/- 3 to 71 +/- 3; P < 0.001), and mean (from 102 +/- 4 to 89 +/- 3; P < 0.001) arterial pressures occurred. Heart rate (75 +/- 4 beats/min to 76 +/- 4 beat/min; P = 0.9), stroke volume (115 +/- 17 to 113 +/- 13; P = 0.9), and cardiac output (8.0 +/- 1 l/m to 8.0 +/- 1l/m; P = 0.8) did not change significantly after spinal anesthesia. Phenylephrine was effective at restoring systolic blood pressure after spinal anesthesia (120 +/- 6 mmHg to 144 +/- 5 mmHg; P < 0.001) but was associated with a decrease in heart rate from 80 +/- 5 beats/min to 60 +/- 4 beats/min (P < 0.001) and in cardiac output from 8.6 +/- 0.7 l/m to 6.2 +/- 0.7 l/m (P < 0.003). Epinephrine was effective at restoring systolic blood pressure after spinal anesthesia (119 +/- 5 mmHg to 139 +/- 6 mmHg; P < 0.001) and was associated with an increase in stroke volume from 114 +/- 12 ml to 142 +/- 17 (P < 0.001) and cardiac output from 7.8 +/- 0.6 l/m to 10.8 +/- 1.1 l/m (P < 0.001). CONCLUSIONS Epinephrine management of tetracaine spinal-induced hypotension increases heart rate and cardiac output and restores systolic arterial pressure but does not restore mean and diastolic blood pressure. Phenylephrine management of tetracaine spinal-induced hypotension decreases heart rate and cardiac output while restoring systolic, mean, and diastolic blood pressure.

Diagnosis and management of acute hypoxemia after drainage of massive pericardial effusion

A 35-year-old, 99-kg female, with a history of hypertension, hypothyroidism, and asthma, complained of fatigue, weight loss, dyspnea, and pedal edema. Her medications included oral thyroxine, omeprazole, iron sulfate, and inhaled beclomethasone. Physical examination revealed clear lung fields, distant heart sounds, and pitting edema in both legs. The chest radiograph showed cardiomegaly and clear lung fields; the electrocardiogram showed sinus tachycardia and low QRS voltage. A transthoracic echocardiogram (Fig 1) showed a large pericardial effusion with diastolic collapse of the right ventricle and both atria. Thyroid function tests performed shortly after admission were normal. On arrival to the operating room for pericardial drainage, the patients blood pressure was 116/94 mmHg, her pulse rate was 107 beats/min, and her oxygen saturation by finger pulse oximeter (on 2 L/rain nasal oxygen) was 100%. After the operative field was prepared, intravenous ketamine and succinylcholine were administered, and a cuffed endotracheal tube inserted in the trachea. A subxyphoid incision was made, and 1.8 L of hemorrhagic pericardial fluid drained. Hemoglobin saturation remained 100% for 10 minutes before drainage of the pericardial effusion, whereupon saturation declined acutely to 85%. Normal breath sounds were heard over each lung field. An arterial blood gas revealed a PaO2 of 57 mmHg, PaCO2 of 53, and pH of 7.35, despite an FIO2 of 1.0, tidal volume of 800 mL, and ventilation rate of 8 breaths/min. Bronchoscopy revealed normal airways and the endotracheal tube tip in proper position. A pulmonary artery catheter was placed, revealing a central venous pressure of 10 mmHg, pulmonary artery pressure of 30/16 mmHg, pulmonary capillary wedge pressure of 13 mmHg, and a cardiac output (CO) of 7.0 L/rain (by thermodilution). A complete TEE examination was performed, revealing a 1.5-cm ostium secundum ASD (measured in the horizontal plane, four-chamber view) with a large right-to-left atrial shunt (by color-flow Doppler), mild global hypokinesis of the left ventricle, severe hypokinesis of the right ventricle, and moderate tricuspid regurgitation (by color-flow Doppler). The patient remained hypoxemic (arterial saturation 63% on FIO 2 of 1.0), despite infusions of norepinephrine (0.07 pg/kg/min) and dopamine (15 ~g/kg/min) to raise systemic vascular resistance and improve right ventricular function, and inhaled nitric oxide (60 ppm) to lower pulmonary vascular resistance. She was

Topical ice slurry prevents brain rewarming during deep hypothermic circulatory arrest in newborn sheep

OBJECTIVES To measure the effect of ice slurry topical cooling on brain surface temperature during deep hypothermic circulatory arrest. DESIGN This was a prospective, controlled experiment. SETTING Animal laboratory at a university hospital. PARTICIPANTS Five control lambs, five treatment (ice slurry) lambs. INTERVENTIONS Animals were studied in two groups: the study group had topical cooling of the head with ice slurry started immediately before circulatory arrest and continued throughout the period of circulatory arrest; control group lambs received no supplemental topical cooling. MEASUREMENTS AND MAIN RESULTS Brain surface temperature, scalp, nasopharyngeal, and rectal temperatures were measured at 5-minute intervals during 45 minutes of circulatory arrest. Lambs receiving topical cooling of the head with ice slurry had a statistically significant decrease in brain surface temperature of 2.2 +/- 1.2 degrees C during circulatory arrest, whereas brain surface temperature increased 1.2 +/- 0.3 degrees C, in control lambs. Equilibration of temperature between the scalp and brain in control lambs produced rewarming of the brain surface. CONCLUSIONS Topical cooling of the head with ice slurry in newborn lambs lowers brain surface temperature during deep hypothermic circulatory arrest. Surrogate temperature monitoring locations such as nasopharyngeal and rectal temperatures varied significantly and do not accurately reflect changes in brain surface temperature.

Reply Treatment of Hypotension after Hyperbaric Tetracaine Spinal Anesthesia

Background:Despite many advantages, spinal anesthesia often is followed by undesirable decreases in blood pressure, for which the ideal treatment remains controversial. Because spinal anesthesia-induced sympathectomy and management with a pure alpha-adrenergic agonist can separately lead to bradycar