PubMed Health⌕ Search

Biomedical subjects

George M Hoffman

Publications and source records attributed to George M Hoffman.

At least 19 recordsLinked to original sources
PubMed2006

Neurologic monitoring on cardiopulmonary bypass: what are we obligated to do?

Improving survival from congenital cardiac repairs using cardiopulmonary bypass has appropriately shifted focus to neurologic outcomes. Hypoxic-ischemic mechanisms are the major cause of neurologic injury in neonatal cardiac surgery, and modifications of techniques of cardiopulmonary bypass can affect organ oxygen delivery and the propensity to injury both during and after surgery. Through successive refinements in the techniques of cardiopulmonary bypass, the risk factors for hypoxic-ischemic injury have been reduced, but not eliminated. The application of specific monitoring to enhance detection of hypoxic conditions associated with neurologic injury would both allow intervention on individual patients and drive refinements in strategies to further reduce risk. Specific neurologic monitoring techniques that can be used during cardiopulmonary bypass include near-infrared spectroscopy, transcranial Doppler ultrasonography, and electroencephalographic techniques. Of these, only near-infrared spectroscopy provides a continuous quantitative signal of the physiologic variable most related to injury and most amenable to intervention. This review will advocate wide adoption of near-infrared spectroscopy monitoring throughout the perioperative period, to enhance detection of hypoxic conditions and to drive patient-specific interventions.

Brain Damage, Chronic↗
PubMed2006

Early cavopulmonary anastomosis after Norwood procedure results in excellent Fontan outcome.

BACKGROUND: Children with univentricular hearts and aortic arch obstruction are treated sequentially with Norwood procedure, superior cavopulmonary anastomosis (SCPA), and Fontan operation. Early SCPA results in lower initial O2 saturation and longer hospitalization, but not increased mortality. We sought to determine the impact of early SCPA on Fontan candidacy and outcomes. METHODS: Eighty-five consecutive patients undergoing Norwood operation between January 1998 and February 2003 were divided into group 1 (SCPA at less than 4 months, n = 33) and group 2 (SCPA at more than 4 months, n = 52). Of the original cohort, 69 have undergone Fontan operation, 7 await Fontan, 1 was transplanted, 3 are not Fontan candidates, and 5 died late after SCPA. Group 1 (n = 25) and group 2 (n = 44) patients who have completed Fontan operation were compared for preoperative and perioperative variables: age, size, O2 saturation, pulmonary artery pressure and size, prevalence of tricuspid regurgitation and ventricular dysfunction, extubation rate in operating room, duration of pleural drainage, hospital stay, and discharge O2 saturation. Late functional status and ventricular function were also compared. Survival was compared for original groups 1 and 2. RESULTS: There were no differences for any preoperative or perioperative variable, or late functional assessment. Actuarial survival at 6 years was also not different (88% +/- 5% for group 1 and 94% +/- 4% for group 2, p = 0.72). CONCLUSIONS: Although initially more cyanotic and hospitalized longer than older peers, younger SCPA patients achieve clinical equivalence by the time of Fontan operation and afterward. We conclude that both short- and long-term outcomes support performance of early SCPA.

Anastomosis, Surgical↗
PubMed2006

Right ventricle-to-pulmonary artery conduit versus Blalock-Taussig shunt: a hemodynamic comparison.

BACKGROUND: A comprehensive assessment of 48 hour postoperative hemodynamics in neonates randomized to the right ventricle-to-pulmonary artery (RV-PA) conduit or modified Blalock-Taussig (BT) shunt for stage 1 palliation of hypoplastic left heart syndrome was performed to determine the potential benefits of the modified technique. METHODS: Randomization to either RV-PA conduit or BT shunt was stratified by surgeon and the presence of aortic atresia. The designated procedure was performed by using hypothermic cardiopulmonary bypass with phenoxybenzamine, continuous cerebral perfusion, pH-stat blood gas management, and continuous postoperative venous oximetry. Differences between treatments were analyzed by time-series generalized least-squares regression, chi2 tests, two-way repeated measures analysis of variance, and the Levene variance ratio test for variability in parameters, as appropriate. RESULTS: All patients underwent the procedure to which they were randomized. There were no differences in age, weight, deep hypothermic circulatory arrest, or cardiopulmonary bypass times between patients receiving the BT shunt (n = 8) or the RV-PA conduit (n = 9). There was one early and one late death in the RV-PA conduit group, and one interstage death in the BT shunt group. Other than diastolic blood pressure (39 mm Hg in BT shunt versus 46 mm Hg in RV-PA conduit, p < 0.001), there were no differences in the mean values of arterial saturation, venous oximetry, mean arterial blood pressure, pulmonary-to-systemic flow ratio (Qp/Qs), or any other physiologic or inotropic support variable between groups. The variability of physiologic values related to pulmonary blood flow was greater in the RV-PA group (Qp/Qs coefficient of variation, 0.91 versus 2.50, p < 0.001). CONCLUSIONS: In this randomized prospective study, no hemodynamic benefits of the RV-PA modification for stage 1 palliation of hypoplastic left heart syndrome were found. Pulmonary blood flow was more variable, and the diastolic blood pressure was higher. These findings did not influence indicators of systemic oxygen delivery with our afterload reduction strategy.

Anastomosis, Surgical↗
PubMed2006

Near infrared spectroscopy monitoring during pediatric aortic coarctation repair.

BACKGROUND: Near infrared spectroscopy (NIRS) measures regional tissue oxygenation continuously and noninvasively and may allow assessment of changes in regional perfusion in real time. METHODS: We used NIRS monitoring to track real-time changes in regional oxygenation (rSO2) above and below the aortic cross-clamp in patients undergoing aortic coarctation repair and routinely stored these data in an operative electronic data base. This allowed us to analyze the changes in rSO2 during aortic coarctation repair for three pediatric age groups (neonates, infants <1 year, and children >1 year). Two site [cerebral (rSO2-C) and somatic thoracodorsal (rSO2-S)] rSO2 monitoring was performed in patients undergoing aortic coarctation repair. Data for rSO2 were analyzed across sites and age groups before, during and after cross-clamp. RESULTS: Twenty-six patients were available for analysis (11 neonates, 5 infants and 10 children). The regional oxygenation below the cross clamp (rSO2-S) declined significantly in all three age groups, but the decrease in neonates and infants <1 year of age was significantly greater than in the older children. CONCLUSIONS: Monitoring rSO2-S provides real-time trend information of regional oxygenation below the aortic cross-clamp. The decline in rSO2-S during aortic cross-clamp was rapid and large in most neonates and young infants <1 year which suggests impairment of regional perfusion presumably because of a lack of adequate collateral circulation to the monitored regional tissue. In contrast, the rSO2-S changed only to a minor degree in most infants and children >1 year, possibly because they had time to develop a more adequate collateral circulation around incomplete aortic obstruction.

Adolescent↗
PubMed2006

A prospective evaluation of opioid weaning in opioid-dependent pediatric critical care patients.

Critically ill children are treated with opioid medication in an attempt to decrease stress and alleviate pain during prolonged pediatric intensive care. This treatment plan places children at risk for opioid dependency. Once dependent, children need to be weaned or risk development of a withdrawal syndrome on abrupt cessation of medication. We enrolled opioid-dependent children into a prospective, randomized trial of 5- versus 10-day opioid weaning using oral methadone. Children exposed to opioids for an average of 3 wk showed no difference in the number of agitation events requiring opioid rescue (3 consecutive neonatal abstinence scores >8 every 2 h) in either wean group. Most of the events requiring rescue occurred on day 5 and 6 of the wean in both treatment groups. Patients may be able to be weaned successfully in 5 days once converted to oral methadone, with a follow-up period after medication wean to observe for a delayed withdrawal syndrome.

Analgesics, Opioid↗
PubMed2006

Assent for treatment: clinician knowledge, attitudes, and practice.

OBJECTIVES: Our purpose for this work was to explore clinician knowledge, attitudes, and practice regarding assent for medical treatment and to compare current practice with existing American Academy of Pediatrics guidelines. METHODS: One of the investigators administered a questionnaire to clinicians who perform procedures on children at an academic tertiary care pediatric hospital to assess knowledge of assent for medical treatment and familiarity with the American Academy of Pediatrics policy statement on assent and to measure clinician attitudes and approaches to consent/assent in pediatrics. RESULTS: Of 35 clinicians enrolled, 23 (66%) had heard of the term "assent," and 9 (26%) of 35 were aware of the American Academy of Pediatrics policy statement on assent. Twenty five (74%) of 34 thought 1 of the main goals of assent was to educate the child. Only 12 (35%) of 34 included the element of seeking the child's agreement as a goal of assent. In practice, the element of explaining the proposed treatment was "always" included by 26 (74%) of 35. The element of seeking the child's agreement was "always" included by 9 (26%) of 35. CONCLUSIONS: The clinicians in this study had limited explicit knowledge of the concept of assent for medical treatment and were largely unaware of the recommendations from the American Academy of Pediatrics. Their attitudes and practice reflected implicit acceptance of the importance of including children in discussions about their medical care and reluctance to give children decision-making authority. A model of medical decision-making for children that includes education but does not allow children to share decision-making authority may be more applicable to clinical practice than the current American Academy of Pediatrics-supported model of assent.

Adolescent↗
PubMed2005

Survival after treatment of rabies with induction of coma.

We report the survival of a 15-year-old girl in whom clinical rabies developed one month after she was bitten by a bat. Treatment included induction of coma while a native immune response matured; rabies vaccine was not administered. The patient was treated with ketamine, midazolam, ribavirin, and amantadine. Probable drug-related toxic effects included hemolysis, pancreatitis, acidosis, and hepatotoxicity. Lumbar puncture after eight days showed an increased level of rabies antibody, and sedation was tapered. Paresis and sensory denervation then resolved. The patient was removed from isolation after 31 days and discharged to her home after 76 days. At nearly five months after her initial hospitalization, she was alert and communicative, but with choreoathetosis, dysarthria, and an unsteady gait.

Adolescent↗
PubMed2005

Complex aortic valve repair as a durable and effective alternative to valve replacement in children with aortic valve disease.

OBJECTIVE: This study was undertaken to determine the utility of aortic valve repair in children. METHODS: A retrospective analysis was conducted on aortic valve surgery from 1973 to 2004 at Children's Hospital of Wisconsin. RESULTS: Procedures were classified as simple repairs (blunt valvotomy, commissurotomy with or without thinning, n = 147), repair of aortic insufficiency with ventricular septal defect (n = 22), complex repairs (any combination of additional procedures including suspension of prolapsed leaflets, leaflet extensions, repair of torn or perforated leaflets, annuloplasty, reduction of sinus of Valsalva plasty, and concomitant repair of supravalvular or subvalvular stenosis, n = 57), and replacements (n = 57, 20 mechanical, 2 porcine, and 35 human valves). Freedoms from reintervention for simple repairs and repair of aortic insufficiency with ventricular septal defect at 10 years were 86% +/- 5% and 93.3% +/- 6%, respectively. For complex valve repair, freedoms from reintervention at 1, 5, and 10 years were 94% +/- 3%, 85% +/- 6%, and 44% +/- 15%, versus 96% +/- 3%, 77% +/- 9%, and 77% +/- 9% for valve replacement ( P = .3). At intermediate follow-up, patients with complex valve repair had a residual gradient of 20 +/- 21 mm Hg, and 94% were free of severe aortic insufficiency. Residual aortic stenosis ( P < .05) but not the preoperative diagnosis of combined aortic stenosis and insufficiency predicted the need for reintervention. CONCLUSION: Freedom from reintervention after complex valve repairs was not different from that after valve replacement, with acceptable residual aortic stenosis and insufficiency. Simple repairs and repair of aortic insufficiency with ventricular septal defect yielded excellent long-term freedom from reintervention.

Adolescent↗
PubMed2005

Systemic venous oxygen saturation after the Norwood procedure and childhood neurodevelopmental outcome.

OBJECTIVE: Neonates with hypoplastic left heart syndrome have impaired systemic oxygen delivery and also have a high risk of hypoxic ischemic brain injury with resultant neurodevelopmental impairment. We hypothesized that decreased postoperative oxygen delivery, as measured on the basis of systemic venous oxyhemoglobin saturation, would be related to persistent neurodevelopmental abnormality assessed in childhood. METHODS: Early perioperative hemodynamic data, prospectively acquired from neonates undergoing staged palliation of hypoplastic left heart syndrome by using deep hypothermic circulatory arrest with uniform perioperative management, were tested for relationship to later neurodevelopmental outcome assessed at age 4 years. RESULTS: Complete hemodynamic and neurodevelopmental data were available in 13 patients aged 7 +/- 8 days at the time of the Norwood procedure and aged 4.5 +/- 0.7 years at follow-up assessment. The subjects scored significantly below the population mean for motor, visual-motor integration, and composite neurodevelopmental outcomes. The 5 (38%) patients with abnormal outcomes had significantly lower postoperative systemic venous oxygen saturation values than those with normal outcomes (46% +/- 8% vs 56% +/- 6%, P = .024). Standard hemodynamic parameters did not differentiate patient outcomes. The risk of abnormal outcome increased with increasing time at a systemic venous oxygen saturation of less than 40% (P < .001). A multivariate model of deep hypothermic circulatory arrest time, systemic venous oxygen saturation, blood pressure, and carbon dioxide tension accounted for 79% of the observed variance (P < .001). CONCLUSIONS: Decreased systemic oxygen delivery in the neonatal postoperative period is associated with hypoxic-ischemic brain injury and childhood neurodevelopmental abnormality. Measures of systemic oxygen delivery should be used to guide perioperative strategies to reduce the risk of hypoxic-ischemic brain injury.

Cardiac Surgical Procedures↗
PubMed2005

Noninvasive assessment of cardiac output.

Improved outcome from shock depends on early detection and correction of circulatory abnormalities. Global cardiac output and oxygen delivery must be adequate and distributed appropriately to meet metabolic demands to prevent the development of multiple organ system dysfunction, prolonged morbidity, and death. Circulatory assessment using standard monitors gives incomplete and sometimes misleading information. This article focuses on the available and emerging technologies that emphasize assessment of blood flow and regional tissue oxygenation.

Calorimetry, Indirect↗
PubMed2005

Aortic valve repair.

Aortic valve replacement options are limited in children, and all of them have disadvantages. Aortic valve repair techniques have evolved slowly and have not gained wide acceptance; however, large series using a variety of techniques demonstrate that valve repair is possible with excellent early hemodynamics and satisfactory intermediate durability. The results of aortic valve repair at the Children's Hospital of Wisconsin are presented. Simple repairs (blunt valvotomy, commissurotomy, or commissurotomy with leaflet thinning) directed at congenital aortic stenosis resulted in 86% +/- 5% freedom from reintervention at 10 years. Repair of aortic insufficiency with ventricular septal defect (VSD) resulted in 93.3% +/- 6% freedom from reoperation at 10 years. Complex repairs included a combination of techniques and yielded 5-year freedom from reintervention of 83% +/- 7% compared with 73% +/- 11% for patients undergoing aortic valve replacement (P = .62). Aortic valve repair provides an alternative to aortic valve replacement in selected patients. The utility of aortic valve repair and aortic valve replacement must be measured not only in freedom from reintervention but also in regression of left ventricular mass and exercise testing. Improvement in outcome depends on better patient selection and suitable bioprosthetic materials.

Adolescent↗
PubMed2004

Changes in cerebral and somatic oxygenation during stage 1 palliation of hypoplastic left heart syndrome using continuous regional cerebral perfusion.

OBJECTIVES: Stage 1 palliation of hypoplastic left heart syndrome requires the interruption of whole-body perfusion. Delayed reflow in the cerebral circulation secondary to prolonged elevation in vascular resistance occurs in neonates after deep hypothermic circulatory arrest. We examined relative changes in cerebral and somatic oxygenation with near-infrared spectroscopy while using a modified perfusion strategy that allowed continuous cerebral perfusion. METHODS: Nine neonates undergoing stage 1 palliation for hypoplastic left heart syndrome had regional tissue oxygenation continuously measured by frontal cerebral and thoraco-lumbar (T10-L2) somatic (renal) reflectance oximetry probes (rSO(2), INVOS; Somanetics, Troy, Mich). Surgery was accomplished using cardiopulmonary bypass with whole-body cooling (18 degrees C-20 degrees C) and regional cerebral perfusion through the innominate artery at flow rates guided by estimated minimum flow requirements and measured rSO(2) during reconstruction of the aortic arch. Data were logged at 1-minute intervals and analyzed using repeated measures analysis of variance. RESULTS: A total of 3176 minutes of data were analyzed. Prebypass cerebral rSO(2) was 65.4 +/- 8.9, and somatic rSO(2) was 58.9 +/- 12.4 (P <.001, cerebral vs somatic). During regional cerebral perfusion, cerebral rSO(2) was 80.7 +/- 8.6, and somatic rSO(2) was 41.4 +/- 7.1 (P <.001). Postbypass cerebral rSO(2) was 53.2 +/- 14.9, and somatic rSO(2) was 76.4 +/- 7.7 (P <.001). The risk of cerebral desaturation was significantly increased after cardiopulmonary bypass. CONCLUSIONS: Cerebral oxygenation was maintained during regional cerebral perfusion at prebypass levels with deep hypothermia. However, after rewarming and separation from cardiopulmonary bypass, cerebral oxygenation was lower compared with prebypass or somatic values. These results indicate that cerebrovascular resistance is increased after deep hypothermic cardiopulmonary bypass, even with continuous perfusion techniques, placing the cerebral circulation at risk postoperatively.

Analysis of Variance↗
PubMed2004

Early cavopulmonary anastomosis in very young infants after the Norwood procedure: impact on oxygenation, resource utilization, and mortality.

BACKGROUND: The optimal timing of second-stage palliation after Norwood operations remains undefined. Advantages of early cavopulmonary anastomosis are early elimination of volume load and shortening the high-risk interstage period. Potential disadvantages include severe cyanosis, prolonged pleural drainage and hospitalization, and excess mortality. We reviewed our recent experience to evaluate the safety of early cavopulmonary anastomosis. METHODS: Eighty-five consecutive patients undergoing post-Norwood operation cavopulmonary anastomosis were divided into group I (cavopulmonary anastomosis at <4 months; n = 33) and group II (cavopulmonary anastomosis at >4 months; n = 52). Groups were compared for age; size; early and late mortality; preoperative, initial postoperative, and discharge oxygen saturation; and duration of mechanical ventilation, intensive care unit stay, pleural drainage, and hospitalization. RESULTS: Group I patients were younger than group II patients (94 +/- 21 days vs 165 +/- 44 days, respectively; P <.001) and smaller (4.8 +/- 0.8 kg vs 5.8 +/- 0.9 kg; P <.001). The preoperative oxygen saturation was not different (group I, 75% +/- 10%; group II, 78% +/- 8%; P =.142). The oxygen saturation was lower immediately after surgery in group I compared with group II (75% +/- 7% vs 81% +/- 7%, respectively; P <.001) but not by discharge (group I, 79% +/- 4%; group II, 80% +/- 4%). Younger patients were ventilated longer (62 +/- 86 hours vs 19 +/- 42 hours; P =.001), in the intensive care unit longer (130 +/- 111 hours vs 104 +/- 94 hours; P =.049), hospitalized longer (12.5 +/- 11.5 days vs 10.3 +/- 14.8 days; P =.012), and required longer pleural drainage (106 +/- 45 hours vs 104 +/- 93 hours; P =.046). Hospital survival was 100% in both groups. Actuarial survival to 12 months was 96% +/- 4% for group I and 96% +/- 3% for group II. CONCLUSIONS: Early cavopulmonary anastomosis after the Norwood operation is safe. Younger patients are more cyanotic initially after surgery and have a longer duration of mechanical ventilation, pleural drainage, intensive care unit stay, and hospitalization.

Age Factors↗
PubMed2004

Alteration of the critical arteriovenous oxygen saturation relationship by sustained afterload reduction after the Norwood procedure.

OBJECTIVES: Hemodynamic vulnerability after the Norwood procedure for hypoplastic left heart syndrome results from impaired myocardial function, and critical inefficiency of parallel circulation. Traditional management strategies have attempted to optimize circulatory efficiency by using arterial oxygen saturation (SaO(2)) as an index of pulmonary/systemic flow balance, attempting to maintain SaO(2) within a theoretically optimal critical range of 75% to 80%. This optimal range of SaO(2) has not been verified clinically, and strategies targeting SaO(2) may be limited by the fact that SaO(2) is a poor predictor of systemic oxygen delivery. We have previously reported higher venous saturation (SvO(2)), lower arteriovenous oxygen content difference, lower systemic vascular resistance, lower pulmonary/systemic flow ratio, and improved survival with the perioperative use of phenoxybenzamine and continuous monitoring of SvO(2). In this investigation, we tested the hypothesis that intense afterload reduction with phenoxybenzamine would modify the SvO(2)-SaO(2) relationship by preventing deterioration of systemic oxygen delivery at high SaO(2). METHODS: Seventy-one consecutive neonates undergoing the Norwood procedure with and without phenoxybenzamine were studied. Perioperative hemodynamic management targeted SvO(2) greater than 50%. Hemodynamic data were prospectively acquired for 48 hours postoperatively and analyzed to assess the effect of phenoxybenzamine on the relationship between SaO(2) and SvO(2) and other hemodynamic indices. Sixty-two patients received phenoxybenzamine 0.25 mg/kg on cardiopulmonary bypass; 9 who did not served as controls. RESULTS: In control patients, SvO(2) peaked at an SaO(2) of 77%, with reduced SvO(2) at SaO(2) > 85% and SaO(2) < 70% (P <.01), while arteriovenous oxygen content difference increased with SaO(2) greater than 80% (P <.001). In patients receiving phenoxybenzamine, the SvO(2) increased linearly with SaO(2) greater than 65% (P <.001), and arteriovenous oxygen content difference was constant at all SaO(2) (P = ns). The SvO(2) was higher, and the arteriovenous oxygen content difference lower, across the whole SaO(2) range with phenoxybenzamine (P <.0001). CONCLUSIONS: A critical range of SaO(2) for optimizing systemic oxygen delivery was confirmed in control patients, and was effectively eliminated by phenoxybenzamine, specifically by eliminating the systemic hypoperfusion associated with high SaO(2). This effect allows higher SaO(2) to be included in a rational hemodynamic strategy to improve systemic oxygen delivery in the early postoperative management of patients receiving intense afterload reduction with phenoxybenzamine. The predictability of SvO(2) from SaO(2) is low in both groups, emphasizing the importance of SvO(2) measurement in these patients.

Arteries↗
PubMed2004

Droperidol for perioperative sedation causes a transient prolongation of the QTc time in children under volatile anesthesia.

BACKGROUND: Droperidol is useful for postoperative sedation in infants and children after cardiac surgery because it provides sedation and akinesia with minimal respiratory depression. However, droperidol has been associated with QT prolongation and ventricular arrhythmias. We investigated, if neuroleptanalgesic doses of droperidol led to QT prolongation and cardiac arrhythmias in children undergoing cardiac surgery. METHODS: We retrospectively analysed electrocardiogram rhythm strips that were obtained before and in time increments after a 100 microg x kg(-1) intravenous bolus of droperidol in 20 children undergoing cardiac surgery. The longest QT interval was determined in each ECG and corrected for heart rate (QTc). All arrhythmias were recorded. RESULTS: Droperidol led to a significant increase in QTc time that was still present at 15 min but had resolved within 30 min after the bolus. No associated arrhythmias were observed. CONCLUSIONS: The statistically significant prolongation of QTc time after a sedative dose of droperidol is of concern because it may increase the risk for malignant cardiac arrhythmias. A large, prospective study is necessary to identify the true risk for arrhythmias after droperidol in this patient population, but our study suggests that any arrhythmogenic risk, if present, will be very transient, since the increase in QTc time was limited to a period of less than 30 min after the bolus.

Adjuvants, Anesthesia↗