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Biomedical subjects

Peter C Laussen

Publications and source records attributed to Peter C Laussen.

At least 19 recordsLinked to original sources
PubMed2007

Potential for donation after cardiac death in a children's hospital.

OBJECTIVES: A task force was convened to decide whether a donation after cardiac death policy should be implemented at Children's Hospital Boston. As part of this process, we sought to determine the number of potential kidney donation after cardiac death donors in our PICUs. METHODS: We examined all 254 deaths in the Medical/Surgical ICU and the Cardiac ICU from 2002 to 2004 and identified potential donation after cardiac death donors. Inclusion criteria were age > or = 3 months, mechanical ventilation, and creatinine < or = 1.5 mg/dL. Exclusion criteria were HIV infection, malignancy other than primary brain tumor or nonmelanoma skin cancer, evidence of ongoing infection, death despite resuscitation attempts, and brain death. RESULTS: Twenty-one of the 254 deaths met criteria for brain death, and 233 patients did not. Of the 116 patients > 3 months of age for whom life support was withdrawn, 92 were not suitable for kidney donation after cardiac death. Of the 24 children identified as potentially eligible for donation after cardiac death, 14 died within 1 hour of withdrawal of support and could have proceeded with donation after cardiac death. In the other 10 children, donation would have been aborted because of prolonged time to death. CONCLUSIONS: Of all patients who died in our ICUs, 5.5% would have been potential candidates for donation after cardiac death. Assuming the rates of parental consent are similar to that of our heart-beating organ donors (47%), a donation after cardiac death protocol could have potentially yielded 7 additional organ donors and 14 additional kidneys over this 3-year period.

Brain Death↗
PubMed2006

Endothelial catabolism of extracellular adenosine during hypoxia: the role of surface adenosine deaminase and CD26.

Extracellular levels of adenosine increase during hypoxia. While acute increases in adenosine are important to counterbalance excessive inflammation or vascular leakage, chronically elevated adenosine levels may be toxic. Thus, we reasoned that clearance mechanisms might exist to offset deleterious influences of chronically elevated adenosine. Guided by microarray results revealing induction of endothelial adenosine deaminase (ADA) mRNA in hypoxia, we used in vitro and in vivo models of adenosine signaling, confirming induction of ADA protein and activity. Further studies in human endothelia revealed that ADA-complexing protein CD26 is coordinately induced by hypoxia, effectively localizing ADA activity at the endothelial cell surface. Moreover, ADA surface binding was effectively blocked with glycoprotein 120 (gp120) treatment, a protein known to specifically compete for ADA-CD26 binding. Functional studies of murine hypoxia revealed inhibition of ADA with deoxycoformycin (dCF) enhances protective responses mediated by adenosine (vascular leak and neutrophil accumulation). Analysis of plasma ADA activity in pediatric patients with chronic hypoxia undergoing cardiac surgery demonstrated a 4.1 +/- 0.6-fold increase in plasma ADA activity compared with controls. Taken together, these results reveal induction of ADA as innate metabolic adaptation to chronically elevated adenosine levels during hypoxia. In contrast, during acute hypoxia associated with vascular leakage and excessive inflammation, ADA inhibition may serve as therapeutic strategy.

Adenosine Deaminase↗
PubMed2006

Extracorporeal membrane oxygenation support of a neonate with percutaneous femoral arterial cannulation.

We describe a neonate with hypoplastic left heart syndrome supported with venoarterial extracorporeal membrane oxygenation with a femoral arterial cannula. A 6-French straight sheath was percutaneously placed in the right femoral artery using the Seldinger technique. Adequate extracorporeal membrane oxygenation flows were achieved, and the patient was successfully de-cannulated. Femoral arterial cannulation in neonates is technically feasible and provides an alternative site for extracorporeal membrane oxygenation cannulation.

Catheterization, Peripheral↗
PubMed2006

Initial experience with fenoldopam after cardiac surgery in neonates with an insufficient response to conventional diuretics.

OBJECTIVE: Fenoldopam, a selective dopamine-1 receptor agonist, causes systemic vasodilation and increased renal blood flow and tubular sodium excretion. We hypothesized that urine output would improve when fenoldopam was added to conventional diuretic therapy after neonatal cardiopulmonary bypass. DESIGN: Retrospective cohort study using a time-series design. SETTING: Pediatric cardiac intensive care unit. PATIENTS: All neonates who received fenoldopam to promote diuresis after cardiac surgery requiring cardiopulmonary bypass from February 2002 through December 2004. INTERVENTIONS: Fenoldopam infusion for inadequate urine output despite conventional diuretics. MEASUREMENTS: Demographics, diagnostic information, and surgical procedures were recorded. Urine output, fluid balance, inotrope scores, diuretic doses, and other clinical variables that may influence diuresis were recorded for the 24-hr period immediately preceding fenoldopam initiation and during the initial 24 hrs of drug administration. MAIN RESULTS: A total of 25 neonates received fenoldopam to promote diuresis after the modified Norwood (n = 14), arterial switch (n = 4), or other operations (n = 7). Heart rate, conventional diuretic dosing, and fluid intake were similar during the 24-hr periods of conventional therapy and fenoldopam use (p = not significant for all), whereas inotrope scores decreased during the study (p = .021). There was a small but statistically significant increase in blood pressure during the 48-hr study period. Median urine output was 3.6 mL x kg(-1) x hr(-1) (range, 0.2-7.2 mL x kg(-1) x hr(-1)) during the 24-hr period of conventional therapy and 5.8 mL x kg(-1) x hr(-1) (range, 1.6-11.7 mL x kg(-1) x hr(-1)) during the initial 24 hrs of fenoldopam administration (Wilcoxon's signed-rank test, p = .001). CONCLUSIONS: Fenoldopam may improve urine output in neonates who are failing to achieve an adequate negative fluid balance despite conventional diuretic therapy after cardiac surgery and cardiopulmonary bypass. This study is limited by its retrospective design and the possibility that urine output improved spontaneously during the treatment period. A randomized, placebo-controlled clinical trial will be required to confirm these findings.

Cardiopulmonary Bypass↗
PubMed2006

Emergent use of extracorporeal membrane oxygenation during pediatric cardiac catheterization.

OBJECTIVES: The goal of this study was to evaluate the utility of extracorporeal membrane oxygenation (ECMO) to resuscitate patients following critical cardiac events in the catheterization laboratory. DESIGN: Retrospective review of medical records. SETTING: Cardiac intensive care unit and cardiac catheterization laboratory at a tertiary care children's hospital. PATIENTS: Pediatric patients cannulated emergently for ECMO in the cardiac catheterization laboratory (n = 22). INTERVENTIONS: ECMO was initiated emergently in the cardiac catheterization laboratory for progressive hemodynamic deterioration due to low cardiac output syndrome or catheter-induced complications. MEASUREMENTS AND MAIN RESULTS: Twenty-two patients were cannulated for ECMO in the catheterization laboratory between 1996 and 2004. Median age was 33 months (range 0-192), median weight 14.8 kg (2.4-75), and median duration of ECMO 84 hrs (2-343). Indications included catheter-induced complication (n = 14), severe low cardiac output syndrome (n = 7), and hypoxemia (n = 1). Three patients (14%) were cannulated in the catheterization laboratory before catheterization for low cardiac output or hypoxemia. During cannulation, 19 patients (86%) were receiving chest compressions; median duration of cardiopulmonary resuscitation was 29 mins (20-57). Eighteen patients (82%) survived to discharge (five of whom underwent cardiac transplantation) and four (18%) died. Of 19 patients who received cardiopulmonary resuscitation during cannulation, 15 (79%) survived to discharge and nine (47%) sustained neurologic injury. There was no significant difference between survivors and nonsurvivors in age, weight, duration of cardiopulmonary resuscitation or ECMO support, pH, or lactate levels. CONCLUSIONS: ECMO is a technically feasible and highly successful tool in the resuscitation of pediatric patients following critical events in the cardiac catheterization laboratory.

Adolescent↗
PubMed2006

Early postoperative outcomes in a series of infants with hypoplastic left heart syndrome undergoing stage I palliation operation with either modified Blalock-Taussig shunt or right ventricle to pulmonary artery conduit.

OBJECTIVE: Previous publications using nonconcurrent series of patients indicate improved survival for patients with hypoplastic left heart syndrome (HLHS) undergoing stage I palliation with a right ventricle to pulmonary artery conduit (NW-RVPA) vs. a modified Blalock-Taussig shunt (NW-BT). We compared postoperative outcomes in a concurrent series of patients with HLHS undergoing an NW-BT procedure vs. NW-RVPA procedure. DESIGN: Perioperative data from 66 consecutive patients who underwent NW-BT (n = 37) or NW-RVPA (n = 29) procedures were retrospectively analyzed. SETTING: Cardiac intensive care unit in a tertiary pediatric hospital. PATIENTS: Charts were reviewed for all patients with the diagnosis of HLHS undergoing the NW-BT or NW-RVPA procedure between January 2002 and December 2003. RESULTS: Cardiopulmonary bypass time was longer in the NW-BT group than in the NW-RVPA group (152.5 +/- 52.0 vs. 134.5 +/- 36.1 mins; p = .04). Postoperative diastolic pressures were higher and the Pao2 to Fio2 ratio profiles were lower for the NW-RVPA group over the first 72 hrs. Time to sternal closure (2 [1-6] vs. 4 [2-41] days; p = .01), duration of mechanical ventilation (113 [49-386] vs. 136 [84-764] hrs; p = .01), time to establish enteral feeds (4 [2-8] vs. 5 [3-22] days; p = .01), length of intensive care unit stay (11 [7-55] vs. 15 [8-90] days; p = .04), and length of hospital stay (16 [11-67] vs. 27 [12-126] days; p = .01) were shorter in the NW-RVPA group. Postoperative mortality was not significantly different between the NW-RVPA group (7%) and NW-BT group (11%). CONCLUSION: At an experienced institution with low stage I palliation mortality for HLHS, there were no differences in early morbidity and mortality between the NW-RVPA and NW-BT procedures. The primary advantage of the NW-RVPA procedure may be faster recovery following surgery and earlier discharge from the hospital.

Analysis of Variance↗
PubMed2006

Real-time continuous glucose monitoring in pediatric patients during and after cardiac surgery.

OBJECTIVES: Given the demonstrated benefit of euglycemia in critically ill patients as well as the risk for hypoglycemia during insulin infusion in children, we sought to validate a subcutaneous sensor for real-time continuous glucose monitoring in pediatric patients during and after cardiac surgery. METHODS: Children up to 36 months of age who were undergoing cardiac bypass surgery were recruited. After anesthetic induction, a continuous glucose-monitoring system sensor (CGMS, Medtronic Minimed, Northridge, CA) was inserted subcutaneously. Sensors remained in place for up to 72 hours. Arterial blood glucose was measured intermittently in the central laboratory (Bayer Rapidlab 860, Tarrytown, NY). Sensor data, after prospective calibration with 6-hourly laboratory values using the proprietary Medtronic Minimed Guardian RT algorithm, were compared with all laboratory glucose values. Statistical analysis was performed to test whether sensor performance was affected by body temperature, inotrope dose, or body-wall edema. RESULTS: Twenty patients were enrolled in the study for a total of 40 study days and 246 paired sensor and laboratory glucose values. Consensus error grid analysis demonstrated that 72.0% of sensor value comparisons were within zone A (no effect on clinical action), and 27.6% of comparisons were within zone B (altered clinical action of little or no effect on outcome), with a mean absolute relative deviation of 17.6% for all comparisons. One comparison (0.4%) was in zone C (altered clinical action likely to affect outcome). No significant correlations were found between sensor performance and body temperature, inotrope dose, or body-wall edema. All patients tolerated the sensors well without bleeding or tissue reaction. CONCLUSIONS: Guardian RT real-time subcutaneous blood glucose measurement is safe and potentially useful for continuous glucose monitoring in critically ill children. Subcutaneous sensors performed well in the setting of hypothermia, inotrope use, and edema. These sensors facilitate identifying and following the effects of interventions to control blood glucose.

Algorithms↗
PubMed2006

Pretransport and posttransport characteristics and outcomes of neonates who were admitted to a cardiac intensive care unit.

OBJECTIVE: The objective for this study was to characterize the impact and the safety of transporting neonates with known or suspected cardiac abnormalities. METHODS: We reviewed retrospectively the charts and computerized records of 192 admissions to a cardiac ICU in 2002. Patients were included when they were < 28 days of age at admission and were transported from adjacent obstetric facilities (local N = 70) or other inpatient medical facilities (transport N = 122). Demographic, clinical, pharmacologic, laboratory, and diagnostic information was obtained before transport (when available) and within 3 hours of arrival. Arrival status was considered optimal when measured metabolic and clinical parameters all were within range. Outcome variables included days on ventilator, days in ICU, days in hospital, and death. RESULTS: Of local admissions, 31 (44%) patients had 61 suboptimal arrival values, including pH < 7.25 (n = 11), saturation < 70% (n = 12), and temperature < 36 degrees C (n = 9). There were 69 undocumented values in 39 patients. Of transported patients, 55 (45%) had 86 suboptimal arrival values, including pH < 7.25 (n = 8), saturation < 70% (n = 14), and temperature < 36 degrees C (n = 13). There were 98 undocumented values in 53 patients. No in-transport deaths or catastrophic events occurred. Local admissions were more likely to have a prenatal diagnosis of heart disease and had more complex disease and higher mortality. Other outcome parameters were not significantly different between the 2 groups. Low admission arterial saturation, pH, and core temperature were not correlated with adverse outcome measures. CONCLUSIONS: Although we did not encounter major transport complications, opportunities exist to optimize arrival status and improve surveillance and documentation.

Female↗
PubMed2005

Improved interstage mortality with the modified Norwood procedure: a meta-analysis.

BACKGROUND: Modification of the Norwood procedure has been reported to improve immediate postoperative mortality compared with the classic Norwood. Interstage mortality has not been shown to be improved with the modified Norwood probably because of the small number of patients from each institution. The goal of this study was to determine if meta-analysis would provide sufficient data to prove statistical difference in interstage mortality for the modified Norwood procedure. METHODS: PubMed was searched using six different terms individually for articles from January 2003 to October 2004. Manuscripts that compared the classic to modified Norwood were reviewed. Mantel-Haenszel analysis was used to evaluate the relationship between treatment method and mortality stratified across hospitals. The Breslow-Day procedure tested homogeneity of odds ratio across hospitals. Separate analyses were performed for inpatient and interstage periods. RESULTS: A total of 4,545 citations was screened. Five manuscripts met the criteria. Seventy-two patients undergoing classic Norwood and 84 patients undergoing modified Norwood survived to initial hospital discharge. The Breslow-Day statistic supported homogeneity of odds ratios for survival across hospitals (chi2 = 2.09, df = 4, p = 0.72). Odds of interstage death was 11.6 times greater (2.2 to 62.1, 95% CI) for the classic Norwood compared with the modified Norwood procedure. This difference was statistically significant by the Mantel-Haenszel chi2 (11.0, p = 0.001). The Breslow-Day statistic supported homogeneity of the odds ratios across hospitals (chi2 = 3.1, df = 4, p = 0.53). CONCLUSIONS: The modified Norwood procedure has a significantly lower interstage mortality compared with the classic Norwood procedure. A large randomized study is needed to determine whether these results remain consistent.

Cardiac Surgical Procedures↗
PubMed2005

A randomized, double-blind, placebo-controlled pilot trial of triiodothyronine in neonatal heart surgery.

OBJECTIVE: This study was undertaken to evaluate the effect of triiodothyronine replacement on the early postoperative course of neonates undergoing aortic arch reconstruction. METHODS: We performed a randomized, double-blind, placebo-controlled trial of triiodothyronine supplementation in neonates undergoing either a Norwood procedure or two-ventricle repair of interrupted aortic arch and ventricular septal defect. Patients were assigned to receive a continuous infusion of triiodothyronine (0.05 micro/kg/h) or placebo for 72 hours after cardiopulmonary bypass. Primary end points were a composite clinical outcome score and cardiac index at 48 postoperative hours. RESULTS: We enrolled 42 patients (triiodothyronine n = 22, placebo n = 20). Baseline characteristics were similar in the treatment groups. Study drug was discontinued prematurely because of hypertension (n = 1) and ectopic atrial tachycardia (n = 1), both cases in the triiodothyronine group. Free and total triiodothyronine levels were higher in the triiodothyronine group than in the placebo group at 24, 48, and 72 postoperative hours (P < .001). The median clinical outcome scores were 2.0 (range 0-4) with triiodothyronine and 2.0 (range 0-7) with placebo (P = .046). Compared with those in the placebo group, neonates assigned to triiodothyronine had shorter median time to negative fluid balance (2.0 vs 2.5 days, P = .027). Cardiac index values were 2.11 +/- 0.64 L/min x m2 with triiodothyronine and 2.05 +/- 0.72 L/min x m2 with placebo (P = .81). Heart rate and diastolic blood pressure were not influenced by triiodothyronine supplementation, but systolic blood pressure was higher in the triiodothyronine group (P < .001). No serious adverse events were attributed to triiodothyronine administration. CONCLUSION: Triiodothyronine supplementation was safe and resulted in more rapid achievement of negative fluid balance after aortic arch reconstruction. Cardiac index at 48 hours was not significantly improved.

Aorta, Thoracic↗
PubMed2005

Evaluation of plasma fentanyl concentrations in infants during cardiopulmonary bypass with low-volume circuits.

OBJECTIVE: The purpose of the study was to measure changes in plasma fentanyl concentrations during infant cardiac surgery using a bypass circuit with low priming volume and to examine the relation of plasma fentanyl concentration and temperature to Bispectral Index (BIS) as an index of conscious level during infant cardiac surgery. DESIGN: Prospective cohort study. SETTING: Tertiary care, academic children's hospital. PARTICIPANTS: Fifteen neonates and infants undergoing cardiac surgery with hypothermic cardiopulmonary bypass (CPB). INTERVENTIONS: Patients were anesthetized with fentanyl, receiving a 30 microg/kg bolus for induction immediately followed by continuous infusion of 0.3 microg/kg/min until skin closure. MEASUREMENTS AND MAIN RESULTS: Intraoperative data and total plasma fentanyl concentration were measured at preinduction; 30 minutes postinduction; sternotomy; aortic cannulation; at 4, 30, and 60 minutes on CPB; and at 1 and 30 minutes off CPB. At the onset of CPB, fentanyl declined from 15 +/- 6 to 11 +/- 5 ng/mL (p < 0.01), increasing to 16 +/- 5 ng/mL (p < 0.01) at 30 minutes on CPB and maintaining a similar level until 30 minutes off CPB. BIS decreased from 88 +/- 20 to 42 +/- 11 (p = 0.02) with induction, declined further during cooling to 9 +/- 11 at the nadir temperature ( p < 0.001), and increased during rewarming to 29 +/- 9 at 1 minute (p < 0.001) and 35 +/- 10 at 30 minutes off CPB ( p < 0.01). Because of wide individual variation in BIS, there was no significant correlation between fentanyl and BIS and temperature. CONCLUSIONS: There was minimal variability in the plasma fentanyl concentration using a low-volume bypass circuit and constant infusion of fentanyl during surgery. There appears to be minimal utility for using BIS during infant cardiac surgery with no relationship between fentanyl concentration, temperature, and BIS established.

Analgesics, Opioid↗
PubMed2005

Anesthetic management of the neonate with congenital complete heart block: a 16-year review.

BACKGROUND: Anesthesia for patients with complete heart block can be associated with significant hemodynamic instability. The aim of this study is to review our anesthetic experience of neonates with congenital complete heart block (CCHB) who underwent placement of either a temporary epicardial pacing system or a permanent epicardial pacemaker. METHODS: The anesthetic management of neonates with CCHB who underwent pacemaker placement at a single institution over a 16-year period was reviewed. RESULTS: Twenty-four neonates were identified, 17 with a structurally normal heart (NL) and seven with associated congenital heart defects (CHD). Median (range) gestational age was 36.9 (26-41) weeks, birth weight 2.9 (1.0-4.1) kg, and baseline heart rate 47 (38-80) b.min(-1). A temporary epicardial pacing system was placed in six patients (four CHD, two NL; P = 0.003) following institution of mechanical ventilation and inotropic support for a low cardiac output state, and a permanent epicardial pacemaker was placed in 18 patients. Atropine 0.02 mg.kg(-1) IV prior to induction (n = 5) increased heart rate less than 20%. Intraoperative hypotension was documented in nine neonates, five of seven with CHD and four of 17 with NL (P = 0.02). In four patients (44%) hypotension occurred despite concurrent inotropic support. Intraoperative cardiac arrest occurred in one neonate, necessitating institution of extracorporeal membrane oxygenation. Two patients (8.3%) died in hospital from complex CHD and complications of prematurity. CONCLUSIONS: Early institution of mechanical ventilation, inotropic support and pacing are necessary in the neonate with CCHB and poor hemodynamic function, particularly with coexisting CHD or prematurity.

Anesthesia↗
PubMed2005

A comparison of the Vasotrac with invasive arterial blood pressure monitoring in children after pediatric cardiac surgery.

The Vasotrac is a device that provides near-continuous and noninvasive arterial blood pressure monitoring and may be an alternative to direct intraarterial measurement. It has been evaluated in adult patients, but minimal information is available for pediatric patients. We evaluated agreement between measurements of arterial blood pressure and heart rate obtained from the Vasotrac versus an arterial catheter in a pediatric population. Children undergoing corrective cardiac surgery were enrolled. Simultaneous arterial blood pressure measurements were obtained postoperatively from the Vasotrac unit and an arterial catheter. Bland-Altman plots were constructed to assess agreement. Paired correlation analysis, bias, and precision calculations were performed. Sixteen patients, mean age 10.1 +/- 2.3 yr and weight 34.6 +/- 11.9 kg, were enrolled. Four-thousand-one- hundred- two paired measurements were obtained. Arterial blood pressures measured noninvasively correlated with catheter measurements with Pearson r values of 0.90, 0.80, and 0.91 for systolic, diastolic, and mean arterial blood pressures, respectively (all P < 0.001). There was excellent agreement between arterial blood pressure measurement methods. Absolute mean differences based on mixed-model regression with 95% confidence intervals were 4.0 mm Hg (3.0-5.0 mm Hg), 4.3 mm Hg (3.1-5.5 mm Hg), and 3.5 mm Hg (2.5-4.0 mm Hg) for systolic blood pressure, diastolic blood pressure, and mean blood pressure, respectively. Arterial blood pressure measurements obtained from the Vasotrac agreed well with invasive arterial monitoring in pediatric patients.

Adolescent↗
PubMed2005

Hemodynamic responses to etomidate on induction of anesthesia in pediatric patients.

Etomidate is often used for inducing anesthesia in patients who have limited hemodynamic reserve. Using invasive hemodynamic monitoring, we studied the acute effects of a bolus of etomidate during induction of anesthesia in children. Twelve children undergoing cardiac catheterization were studied (mean age, 9.2 +/- 4.8 yr; mean weight, 33.4 +/- 15.4 kg); catheterization procedures included device closure of secundum atrial septal defects (n = 7) and radiofrequency catheter ablation procedures for supraventricular tachycardia (n = 5). Using IV sedation, a balloon-tipped pulmonary artery catheter was placed to measure intracardiac and pulmonary artery pressures and oxygen saturations. Baseline measurements were recorded and then repeated after a bolus of IV etomidate (0.3 mg/kg). For the entire group, no significant changes in right atrial, aortic, or pulmonary artery pressure, oxygen saturations, calculated Qp:Qs ratio or systemic or pulmonary vascular resistance were detected after the bolus dose of etomidate. The lack of clinically significant hemodynamic changes after etomidate administration supports the clinical impression that etomidate is safe in children. Further research is needed to determine the hemodynamic profile of etomidate in neonates and in pediatric patients with severe ventricular dysfunction and pulmonary hypertension.

Adolescent↗
PubMed2005

A comparison of radial artery blood pressure determination between the Vasotrac device and invasive arterial blood pressure monitoring in adolescents undergoing scoliosis surgery.

UNLABELLED: The Vasotrac device (Medwave, Arden Hills, MN) allows noninvasive measurement of arterial blood pressure (BP) and arterial waveform. We have previously demonstrated agreement between the Vasotrac and continuous intraarterial BP monitoring in children with a stable circulation after cardiac surgery in the cardiac intensive care unit. To assess this monitor during different physiologic conditions, we studied the Vasotrac in anesthetized adolescent children undergoing scoliosis surgery in the prone position, with or without controlled hypotension. Eleven children undergoing surgery for idiopathic scoliosis were enrolled in this study. The anesthetic consisted of primarily a nitrous oxide and narcotic technique with controlled hypotension obtained using IV labetalol. Data were analyzed using correlations, mean error, and Bland-Altman plots. Noninvasive BP measured by the Vasotrac correlated closely with intraarterial BP. Waveforms displayed by the two systems were qualitatively similar. Correlation between the two methods for systolic, diastolic and mean BP was r = 0.82, r = 0.83, and r = 0.90, respectively. We conclude that noninvasive BP measurement using the Vasotrac monitor enables near-continuous and reliable monitoring of BP during anesthesia in the prone position and pharmacologic-induced hypotension. IMPLICATIONS: The Vasotrac, a noninvasive arterial blood pressure monitor, performs well in the prone position in adolescent patients undergoing scoliosis surgery using a technique of mild-to-moderate induced hypotension.

Adolescent↗
PubMed2005

An evaluation of bilateral monitoring of cerebral oxygen saturation during pediatric cardiac surgery.

Cerebral oximetry is a technique that enables monitoring of regional cerebral oxygenation during cardiac surgery. In this study, we evaluated differences in bi-hemispheric measurement of cerebral oxygen saturation using near-infrared spectroscopy in 62 infants undergoing biventricular repair without aortic arch reconstruction. Left and right regional cerebral oxygen saturation index (rSO2i) were recorded continuously after the induction of anesthesia, and data were analyzed at 12 time points. Baseline rSO2i measurements were left 65 +/- 13 and right 66 +/- 13 (P = 0.17). Mean left and right rSO2i measurements were similar (< or =2 percentage points/absolute scale units) before, during, and after cardiopulmonary bypass, irrespective of the use of deep hypothermic circulatory arrest. Further longitudinal neurological outcome studies are required to determine whether uni- or bi-hemispheric monitoring is required in this patient population.

Brain↗
PubMed2004

Identification of pressure passive cerebral perfusion and its mediators after infant cardiac surgery.

Cerebrovascular pressure autoregulation (CPA) regulates cerebral blood flow (CBF) in relation to changes in mean arterial blood pressure (MAP). Identification of a pressure-passive cerebral perfusion and the potentially modifiable physiologic factors underlying it has been difficult to achieve in sick infants. We previously validated the near-infrared spectroscopy-derived hemoglobin difference (HbD) signal (cerebral oxyhemoglobin - deoxyhemoglobin) as a reliable measure of changes in CBF in animal models. We now sought to determine whether continuous measurements of DeltaHbD would correlate to middle cerebral artery flow velocity (CBFV), allow identification and quantification of pressure-passive state, and help to delineate potentially modifiable factors. We enrolled 43 infants (2 d to 7 mo old) who were undergoing open cardiac surgery and cardiopulmonary bypass. At 6 and 20 h after surgery, we measured changes in HbD, CBFV (by transcranial Doppler), and MAP at different end-tidal CO(2) levels. We assigned a pressure-passive index (PPI) to each study on the basis of the relative duration of significant coherence between DeltaMAP and DeltaHbD. We found a significant relationship between DeltaHbD and DeltaCBFV at both time points. At 6 h after surgery, we showed high concordance (coherence > 0.5; PPI > or = 41%) between DeltaMAP and DeltaHbD, consistent with disturbed CPA in 13% of infants. End-tidal CO(2) values > or = 40 mm Hg and higher MAP variability both were associated with increased odds (p < 0.001) of autoregulatory failure. This approach provides a means to identify and quantify disturbances of CPA. High CO(2) levels and fluctuating MAP are two important preventable factors associated with disturbed CPA.

Blood Pressure↗