One-Year Outcome Study of Anatomic Reconstruction of Lesser Metatarsophalangeal Joints

Background: Lesser metatarsophalangeal joint (MTPJ) and plantar plate pathologies are commonly seen forefoot conditions. Traditional rebalancing techniques are commonly used but can have concerning adverse effects. The purpose of this study was to analyze the 1-year outcomes of a new technique consisting of anatomic repair of the plantar plate and collateral ligaments involving lesser MTPJs. Methodology: A retrospective cohort study of 50 consecutive patients treated with anatomic plantar plate and collateral ligament reconstruction were evaluated for lesser MTPJ imbalances between 2013 and 2016. The primary outcome was postoperative digital stability defined as a normal dorsal drawer test and normal paper pull-out test. Secondary outcomes included pre- and postoperative visual analogue scale pain measurements, MTPJ radiographic alignment, and ACFAS Forefoot module scores. Results: All patients had digital instability prior to the surgical intervention. Final follow-up revealed that 92% of patients showed improved digital stability, P = .0005. Multivariate regression found statistically significant improvement in pain reduction via the visual analogue scale of 51.2 mm (P < .0001) and ACFAS Forefoot module scores improved to 92 (P < .0001). The 45 joints with preoperative abnormal transverse plane deformity, had either complete (n = 29) or partial (n = 16) radiographic MTPJ correction. Conclusion: These results suggest that anatomic repair of lesser MTPJ improved digital stability, pain, function and radiographic alignment with greater than one year of follow-up.Levels of Evidence: Level IV: Retrospective cohort study.

Development and Validation of the Foot Union Scoring Evaluation Tool for Arthrodesis of Foot Structures

Reliable evaluation of osseous consolidation after pedal arthrodesis can be difficult, and the presence or absence of radiographic healing often dictates care. Plain radiographs remain the mainstay imaging tool owing to their cost, efficiency, and low radiation exposure. Applying radiographic parameters that can reliably determine osseous healing is essential. However, currently, no reliable or validated measures are available to determine osseous union of any joint in the foot or ankle. The purpose of the present study was to develop a radiographic healing scoring system that would enhance the diagnostic healing assessment after joint arthrodesis of the foot or ankle. We adapted several existing scales previously validated for fracture healing in the leg, because no study has attempted to apply this to a joint fusion model. A total of 150 cases were evaluated by 6 blinded assessors to test the interrater reliability of the subjective healing assessment compared with the proposed scoring system. The radiographs were classified by the postoperative period: ≤4 weeks, 5 to 12 weeks, and >12 weeks. The initial proposed scale was found to have high interrater reliability but was burdensome. Using a priori item reduction protocols, a limited 5-item scale further improved the internal consistency and reduced the burden. The result was excellent interrater reliability (α = 0.978, standard deviation 0.02, 95% confidence interval 0.96 to 0.99) among all assessors compared with the reduced reliability (α = 0.752) for subjective arthrodesis healing. Intrarater reliability was also found to be superior using a test-retest method. The reliability of this system appeared superior to the subjective assessment of arthrodesis healing, even in the absence of clinical correlates, after foot arthrodesis.

Bispectral index monitoring during infant cardiac surgery: relationship of BIS to the stress response and plasma fentanyl levels

BACKGROUND

We evaluated the relationship of the bispectral index (BIS) to commonly used indices of depth of anaesthesia in 19 infants enrolled in a prospective study of the stress response to hypothermic cardiopulmonary bypass.

METHODS

Group 1 (n=8) received high-dose fentanyl by bolus technique; group 2 (n=6) received high-dose fentanyl by continuous infusion; and group 3 (n=5) received a fentanyl-midazolam infusion. Blood pressure (BP), heart rate (HR) and plasma epinephrine, norepinephrine, cortisol, ACTH, glucose, lactate and fentanyl were analysed 15 min postinduction, 15 min poststernotomy, 15 min on CPB during cooling and during skin closure.

RESULTS

Mean BIS (SD) values for all 19 patients were 45.3 (12.3), 40.4 (14.5), 24.4 (12.4) and 47.9 (13.9), at the successive time points. No significant differences were observed in changes in BIS over time between the groups. A significant correlation was found 15 min postinduction between BIS and BP (systolic r=0.51, mean r=0.56) in all groups, but not between BIS and HR. BIS did not correlate with BP or HR at any other time point. There was no significant correlation between BIS and hormonal, biochemical or plasma fentanyl levels for any group at any time point.

CONCLUSIONS

We were unable to demonstrate a relationship between the BIS and haemodynamic, metabolic or hormonal indices of anaesthetic depth. Further evaluation of the BIS algorithm is required in neonates and infants.

Stress response in infants undergoing cardiac surgery: a randomized study of fentanyl bolus, fentanyl infusion, and fentanyl-midazolam infusion

There have been significant changes in the management of neonates and infants undergoing cardiac surgery in the past decade. We have evaluated in this prospective, randomized, double-blinded study the effect of large-dose fentanyl anesthesia, with or without midazolam, on stress responses and outcome. Forty-five patients < 6 mo of age received bolus fentanyl (Group 1), fentanyl by continuous infusion (Group 2), or fentanyl-midazolam infusion (Group 3). Epinephrine, norepinephrine, cortisol, adrenocortical hormone, glucose, and lactate were measured after the induction (T1), after sternotomy (T2), 15 min after initiating cardiopulmonary bypass (T3), at the end of surgery (T4), and after 24 h in the intensive care unit (T5). Plasma fentanyl concentrations were obtained at all time points except at T5. Within each group epinephrine, norepinephrine, cortisol, glucose and lactate levels were significantly larger at T4 (P values < 0.01), but there were no differences among groups. Within groups, fentanyl levels were significantly larger in Groups 2 and 3 (P < 0.001) at T4, and among groups, the fentanyl level was larger only at T2 in Group 1 compared with Groups 2 and 3 (P < 0.006). There were no deaths or postoperative complications, and no significant differences in duration of mechanical ventilation or intensive care unit or hospital stay. Fentanyl dosing strategies, with or without midazolam, do not prevent a hormonal or metabolic stress response in infants undergoing cardiac surgery.

IMPLICATIONS

We demonstrated a significant endocrine stress response in infants with well compensated congenital cardiac disease undergoing cardiac surgery, but without adverse postoperative outcome. The use of large-dose fentanyl, with or without midazolam, with the intention of providing "stress free" anesthesia, does not appear to be an important determinant of early postoperative outcome.

Parameters associated with perioperative baffle fenestration closure in the Fontan operation

OBJECTIVE

To identify clinical parameters indicating perioperative fenestration closure in children who underwent the fenestrated Fontan operation.

DESIGN

Retrospective.

SETTING

Single children's hospital.

PARTICIPANTS

Patients who underwent a fenestrated Fontan operation in 1996 through 1997 (n = 101).

INTERVENTION

A fenestrated Fontan operation was performed in children with single-ventricle physiology.

MEASUREMENTS AND MAIN RESULTS

Early perioperative closure of the fenestration occurred in 14 patients (group 1), whereas the fenestration remained patent in 87 patients (group 2). The groups were compared by the following parameters: demographics, cardiac catheterization and ultrasound data, and use of aspirin or warfarin preoperatively and intraoperatively by assessing the composition of the cardiopulmonary bypass solution, use of ultrafiltration and antifibrinolytics, protamine dose, last hematocrit on cardiopulmonary bypass, and requirement of blood products. Immediately postoperatively in the intensive care unit (ICU), cardiac filling pressures (central venous and left atrial pressure), coagulation profile, cardiac rhythm, chest tube drainage, length of stay in the ICU, and use of atrial pacing were reviewed. Significant indicators of early fenestration closure in this study as determined by multivariate stepwise logistic regression were a high transpulmonary pressure gradient (p = 0.015) and a higher oxygen saturation (p = 0.001) 1 hour after arrival in the ICU, a low fibrinogen level (p < 0.0001), and the need for temporary atrial pacing (p = 0.029). The fenestration was reopened in 13 patients in group 1. In 101 patients, there was no early mortality, and all patients survived to discharge.

CONCLUSION

Factors that correlated with postoperative fenestration closure in the fenestrated Fontan operation in this study were a high transpulmonary pressure gradient and a high oxygen saturation 1 hour after arrival in the ICU, a low fibrinogen level, and the need for temporary atrial pacing.

Synthetic antifibrinolytics are not associated with an increased incidence of baffle fenestration closure after the modified Fontan procedure

OBJECTIVE

To determine if the lysine analog antifibrinolytic agents, epsilon-aminocaproic acid and tranexamic acid, are associated with early closure of the baffle fenestration after the modified Fontan procedure.

DESIGN

Retrospective chart review.

SETTING

University hospital.

PARTICIPANTS

Seventy-four successive patients underwent the modified Fontan procedure. Three patients received aprotinin and were excluded. A total of 71 patients were analyzed.

INTERVENTIONS

Charts were examined for variables known to be associated with baffle fenestration closure in the modified Fontan procedure.

MEASUREMENTS AND MAIN RESULTS

Occurrence of baffle fenestration closure, oxygen saturation, central venous pressure, left atrial pressure, transpulmonary gradient, chest tube drainage volume, chest tube drainage duration, intensive care unit (ICU) duration, and total inpatient duration were compared between the 33 patients who received antifibrinolytics and the 38 patients who did not. One patient of 71 had baffle fenestration closure in the first 48 hours after surgery. Oxygen saturation, central venous pressure, left atrial pressure, transpulmonary gradient, chest tube drainage volume, chest tube drainage duration, days in ICU, and total inpatient duration were not significantly different between the two groups.

CONCLUSIONS

Use of epsilon-aminocaproic acid and tranexamic acid is not associated with early baffle fenestration closure after the modified Fontan procedure. It is concluded that these agents can be used without increasing the risk of spontaneous baffle fenestration closure.

The effect of hematocrit on cerebral blood flow velocity in neonates and infants undergoing deep hypothermic cardiopulmonary bypass

Varying degrees of hemodilution are used during deep hypothermic cardiopulmonary bypass. However, the optimal hematocrit (Hct) level to ensure adequate oxygen delivery without impairing microcirculatory flow is not known. In this prospective, randomized study, cerebral blood flow velocity in the middle cerebral artery was measured using transcranial Doppler sonography in 35 neonates and infants undergoing surgery with deep hypothermic cardiopulmonary bypass. Patients were randomized to low Hct (aiming for 20%) or high Hct (aiming for 30%) during cooling on cardiopulmonary bypass (CPB). Systolic (V(s)), mean (Vm), and diastolic (Vd) cerebral blood flow velocity, as well as pulsatility index (PI = [V(s) - Vd]/Vm) and resistance index (RI = [V(s) - Vd]/V(s)) were recorded at six time points: postinduction, at cannulation, after 10 min cooling on CPB, rewarmed to 35 degrees C on CPB, immediately off CPB, and at skin closure. Vm was significantly lower in the high Hct group compared with that in the low Hct group during cooling (P < 0.01). Postinduction, the high Hct group demonstrated significantly lower Vd immediately off CPB (P < 0.01) and significantly lower Vm and V(s) at skin closure (P < 0.001). We conclude that there is an inverse relation between hematocrit and cerebral blood flow velocity during deep hypothermic cardiopulmonary bypass in neonates and infants.

IMPLICATIONS

There is an inverse relation between hematocrit and cerebral blood flow velocity during deep hypothermic cardiopulmonary bypass in neonates and infants. Further studies correlating Hct and cerebral blood flow velocity with cerebral metabolic rate and neurologic outcome are necessary to determine the optimal Hct during deep hypothermic cardiopulmonary bypass.

The influence of cardiopulmonary bypass on ionized magnesium in neonates, infants, and children undergoing repair of congenital heart lesions

The purpose of this study was to measure the ionized magnesium (iMg) concentrations in children undergoing the correction of congenital heart defects. iMg levels were measured in 115 consecutive patients at five sample periods: prebypass, onset of bypass, during rewarming, immediately postbypass, and 1 h postbypass using an ion-selective electrode of the NOVA-CRT 8 (Nova Biomedical, Watham, MA). The incidence of dysrythmias was noted. Patients were divided into two groups: those who received Plegisol as the cardioplegic solution and those who did not. This study demonstrates that iMg decreases with the onset of cardiopulmonary bypass (CPB) in patients who weigh < 10 kg. In the Plegisol group, all subgroups of patients demonstrated statistically higher iMg during the rewarming phase of CPB, immediately post-CPB, and 1 h post-CPB, when compared with control values. The probability of dysrhythmias in the Plegisol group was almost twice that of the non-Plegisol group. However, this did not reach statistical significance (P = 0.22). The results of our study demonstrate that the use of CPB on pediatric patients produces alterations in the iMg. The changes differ depending on both patient weight and the use of a magnesium-containing cardioplegic solution, exemplified here by Plegisol. The role of these changes in iMg on dysrhythmias could not be further evaluated.

Video-assisted thoracoscopic surgery for the treatment of congenital cardiac defects in the pediatric population

Recent technologic advances have contributed to a renewed interest in thoracoscopic surgery. In our institution, thoracoscopy through video-assisted technology has been successfully applied to congenital heart surgery. We reviewed the charts of 45 consecutive patients (ASA physical status 11-IV) who underwent video-assisted thoracoscopic surgery (VATS) for various congenital heart defects. The mean age of the patients was 2.65 yr and the mean weight was 11.78 kg. The surgical procedures included patent ductus arteriosus interruption (n = 28) and vascular ring division (n = 8), and 9 patients had miscellaneous procedures. The most commonly used anesthetic regimen consisted of isoflurane, pancuronium, fentanyl, air, and oxygen. Seven patients were managed with one-lung ventilation, the remainder by two-lung ventilation with surgical lung retraction. Intraoperative desaturation occurred in 12 patients (26.7%) but resolved quickly with brief reexpansion of the lungs. Postoperative complications included: pleural effusions (n = 3), chylothorax (n = 2), right upper lobe atelectasis (n = 1), small pneumothorax (n = 1), and vocal cord paralysis (n = 1). Seven patients (15.5%) required conversion to a thoracotomy for insufficient exposure (n = 4) or due to concern over bleeding (n = 3). This experience with VATS in pediatric patients with congenital heart disease may provide a database for comparison with others who work with the VATS technique.

Resection of a massive sacrococcygeal teratoma using hypothermic hypoperfusion: a novel use of extracorporeal membrane oxygenation

A 33-week-gestation infant with a massive sacrococcygeal teratoma weighted 4,000 g, but the actual weight of the infant was approximately 1,500 g. With the potential for massive blood loss and impaired lung compliance during resection, some type of cardiopulmonary support was necessary. Resection was undertaken with the assistance of venoarterial extracorporeal membrane oxygenation (ECMO) and hypothermic hypoperfusion. Immediately after removal of the tumor, which weighted 2,420 g, the infant was decannulated from ECMO, and the carotid artery was primarily reconstructed end-to-end. The amount of intraoperative blood loss was 550 mL Postoperatively, the child weighted 1,580 g. Follow-up head ultrasound results were normal, and the patient has done well. This is the first reported case in which ECMO with hypothermic hypoperfusion was used for resection of a massive tumor. This experience shows that ECMO is both useful and safe as a means of temporary cardiopulmonary support for resection of massive tumors in infants.

Transcatheter closure of ventricular septal defects: hemodynamic instability and anesthetic management

The technique of transcatheter ventricular septal defect (VSD) device closure may be associated with significant hemodynamic instability. The anesthetic records and catheterization data of 70 consecutive transcatheter VSD closures between February 1989 and September 1992 were reviewed, and risk factors associated with hemodynamic instability evaluated. In 28 of 70 procedures (40%), hypotension (> 20% decrease in systolic blood pressure from baseline) occurred; 12 responded to administration of fluids intravascularly alone, whereas 16 patients required additional acute resuscitation. Significant dysrhythmias occurred during 20 (28.5%) anesthetics associated with hypotension and requiring treatment or catheter withdrawal. ASA physical status, precatheterization indication for device placement, and patient size were not predictive of hemodynamic instability during the procedure. Blood transfusions were necessary in 38 (54.4%) cases and were size-related, with patients weighing less than 10 kg requiring a significantly larger transfusion volume (25.1 +/- 12.4 mL/kg). After 35 procedures (50%) patients were admitted directly to the intensive care unit (ICU) due primarily to hemodynamic instability or procedure duration; 24 (68%) required mechanical ventilation. No deaths occurred; there was no late morbidity due to catheterization-related events. Intravenous sedation was used for the initial catheterizations, maintained with a combination of midazolam, ketamine, and morphine. Subsequently general intravenous or inhaled anesthesia was predominantly used during transesophageal echocardiography and internal jugular vein cannulation. We conclude that hemodynamic instability is common during device closure of VSDs, and is likely to be an inescapable feature of these procedures in many patients because of the technique necessary for device placement.

Effects of propofol or isoflurane anesthesia on cardiac conduction in children undergoing radiofrequency catheter ablation for tachydysrhythmias

BACKGROUND

To determine suitability for ablation procedures in children, two commonly used anesthetic agents were studied: propofol and isoflurane.

METHODS

Twenty patients presenting for a radiofrequency catheter ablation procedure were included and randomly assigned to two groups. A baseline electrophysiology study was performed during anesthesia with thiopental, alfentanil, nitrous oxide, and pancuronium in all patients. At the completion of the baseline electrophysiology study (EPS), 0.8-1.2% isoflurane was administered to patients in group 1 and 2 mg/kg propofol bolus plus an infusion of 150 micrograms.kg-1.min-1 was administered to patients in group 2. Nitrous oxide and pancuronium were used throughout the procedure. After 30 min of equilibration, both groups underwent a repeat EPS. The following parameters were measured during the EPS: cycle length, atrial-His interval, His-ventricle interval, corrected sinus node recovery time, AV node effective refractory period, and atrial effective refractory period. Using paired t tests, the electrophysiologic parameters described above measured during propofol or isoflurane anesthesia were compared to those measured during baseline anesthesia. Statistical significance was accepted as P < 0.05.

RESULTS

There was no statistically significant difference in the results obtained during baseline anesthesia when compared with those measured during propofol or isoflurane anesthesia.

CONCLUSIONS

Neither propofol nor isoflurane anesthesia alter sinoatrial or atrioventricular node function in pediatric patients undergoing radiofrequency catheter ablation, compared to values obtained during baseline anesthesia with alfentanil and midazolam.

Paediatric cardiac catheterization: innovations

In recent years interventional procedures have been introduced to the field of paediatric cardiac catheterization. These procedures continue to develop in complexity and increasingly are being applied to patients with reduced cardiovascular reserve, as an alternative to cardiac surgery or when cardiac surgery with cardiopulmonary bypass is contraindicated. More frequently anaesthetists are being called upon to provide support in sedating, anaesthetizing or/and resuscitating these patients. The purpose of this review is to give a comprehensive update of the interventional procedures and to review the anaesthetic management techniques as they apply to the catheterization laboratory. We will discuss possible complications and management strategies from our own experience and the experience of others. We have observed that as more complicated procedures are performed the anaesthetist plays a pivotal role in the management of the patient from arrival to departure from the cardiac catheterization laboratory, and in preventing mortality and major morbidity. Although the economic consequences of interventional cardiological techniques remain unclear, the field continues to expand and more complex procedures are continually being introduced.

Anatomic subtype and survival after reconstructive operation for hypoplastic left heart syndrome

We conducted a retrospective study of 78 patients who underwent palliative reconstructive operation for hypoplastic left heart syndrome representing an entire consecutive experience between 1983 and 1991 to identify predictors of mortality that might enable more appropriate triage of patients to either reconstruction or transplantation. Twenty-nine patients had aortic atresia, mitral atresia; 18 had aortic stenosis, mitral stenosis; 20 had aortic atresia and mitral stenosis; and 11 had miscellaneous forms of hypoplastic left heart syndrome. There were 29 hospital deaths (37%). A worst preoperative pH (p = 0.01) and immediate preoperative pH (p = 0.03) less than the median were predictors of hospital mortality. The anatomic subgroup aortic atresia, mitral stenosis (p = 0.06) had a possible increased hospital mortality. One patient was lost to follow-up. The Kaplan-Meier survival estimate among hospital survivors was 34% at 3 years and 25% at 5 years. The anatomic subgroup aortic atresia, mitral atresia (p = 0.02) had a worse late outcome (11% 3-year survival) whereas the subgroup aortic stenosis, mitral stenosis (p = 0.04; 76% 3-year survival) had a better late outcome. There were no other significant predictors of late survival other than immediate prerepair pH (p = 0.05). Interpretation of this experience is complicated by the large number of different surgical techniques used for both first-stage neonatal reconstruction and the Fontan procedure plus introduction of the bidirectional Glenn shunt as an intermediate step midway through the experience. Nevertheless in this time frame and with the variety of techniques used, this experience demonstrates that patients with aortic atresia, mitral atresia, particularly those who have been very acidotic in the neonatal period, are least likely to do well with the reconstructive approach to hypoplastic left heart syndrome and are the most appropriate subgroup to be directed to transplantation. Patients with aortic stenosis, mitral stenosis have an excellent late outcome with the reconstructive approach.

Transcatheter closure of atrial septal defects: hemodynamic complications and anesthetic management

Transcatheter closure of atrial septal defects using a double-umbrella (clamshell) device can now be performed during an overnight hospital stay with little morbidity and no mortality. The initial 2-yr experience with anesthetic care for the procedure was collected and subsequently analyzed. Primary anesthetic care was given in 118 cases and urgent anesthetic intervention was required in another four cases. Anesthesia with spontaneous ventilation in patients with unprotected airways using intravenous ketamine and midazolam (average cumulative doses 1.4 and 0.17 mg.kg-1.h-1, respectively) was used in 93 cases (77%); mean maximum PaCO2 value was 41 +/- 6 mm Hg. In 29 patients (23%) tracheal intubation and muscle paralysis were used to facilitate control of airway and ventilation. Anesthetic-related complications occurred in three patients: ventilatory compromise developed in two patients in the spontaneous ventilation group and one patient experienced awareness during endotracheal anesthesia with paralysis. Procedural complications that altered anesthetic management were more frequent, including embolization of the clamshell device requiring surgical retrieval in two of six embolizations, intracardiac air embolization (four cases), tricuspid regurgitation (one case), device malplacement requiring late operation (one case), and transient brachial plexus injury (three cases). Anesthesia for transcatheter atrial septal defect closure allows precise device placement, prompt control of hemodynamic complications, and transesophageal echocardiographic monitoring of device placement. Although general anesthesia with spontaneous ventilation using ketamine and midazolam was usually safe and effective, tracheal intubation for control of airway and ventilation was sometimes necessary for safety and for optimal operating conditions. Familiarity with transcatheter closure techniques and close communication with the catheterization team is essential to minimize and treat associated complications.(ABSTRACT TRUNCATED AT 250 WORDS)

High-dose fentanyl reduces intraoperative ventricular fibrillation in neonates with hypoplastic left heart syndrome

STUDY OBJECTIVE

To determine retrospectively the effect of high-dose opiate-oxygen (O2) anesthetic technique on intraoperative ventricular fibrillation in high-risk neonates.

DESIGN

Retrospective chart review of different anesthetic techniques in a partially contemporaneous patient group (1981 to 1983).

SETTING

Cardiac anesthesia service at a university pediatric hospital.

PATIENTS

Forty neonates undergoing Norwood Stage I repair of hypoplastic left heart syndrome.

INTERVENTIONS

High-dose fentanyl-O2 anesthesia in 30 neonates and low-dose morphine sulfate 50%-nitrous oxide (N2O) in 10 neonates.

MEASUREMENTS AND MAIN RESULTS

Clinical condition assessed by preoperative and intraoperative arterial blood gases, requirements for sodium bicarbonate (NaHCO3), need for inotropic and pressor support, and vital signs. Outcome assessments by intraoperative ventricular fibrillation (frequency before and after bypass) and hospital mortality. Clinical condition and hospital mortality were no different. The frequency of intraoperative ventricular fibrillation was significantly different: 3% with high-dose fentanyl and 50% with morphine-N2O (p less than 0.005).

CONCLUSIONS

High-dose opiate-O2 anesthesia in these patients markedly decreased intraoperative ventricular fibrillation. Other clinical reports and recent experimental work suggest that this finding is due to high-dose opiates rather than the avoidance of N2O.

Hormonal-metabolic stress responses in neonates undergoing cardiac surgery

Hormonal and metabolic responses were measured in 15 neonates who underwent repair of complex congenital heart defects during a standardized anesthetic protocol. Four of the 15 neonates died postoperatively in the intensive care unit. Analysis of arterial plasma samples obtained before, during, and 24 h after surgery showed that plasma epinephrine, norepinephrine, cortisol, glucagon, and beta endorphin increased in all patients (P less than 0.05). Insulin levels increased only at the end of surgery but remained elevated for 24 h postoperatively (P less than 0.02). Intraoperative metabolic changes were characterized by hyperglycemia and lactic acidemia that persisted postoperatively. This pattern of neonatal stress responses is distinct from and more extreme than that seen in adult cardiac surgical patients. The four neonates who died postoperatively tended to have higher stress responses intra- and postoperatively despite having been indistinguishable from survivors by the usual clinical and hemodynamic criteria. These preliminary results suggest that neonatal hormonal and metabolic responses to cardiac surgical operations in neonates are extreme and are associated with a high hospital mortality rate.

Combined mechanical and chemical thrombolysis in an experimental animal model: evaluation by angiography and angioscopy

In an experimental animal model of femoral artery thrombosis, contrast angiography was compared to intravascular angioscopy. Additionally, the effect of mechanical, rotational thrombectomy and the additive benefit of the administration of intravascular streptokinase were assessed by means of both procedures. After external forceps crush injury alone, contrast angiograms were generally normal (6 of 14) or showed minimal luminal irregularity (3 of 14), and 5 of 14 had 30% to 50% stenosis. With angioscopy, none appeared normal, and 14 of 14 showed thrombi layered along the wall, as well as intimal flaps, and 6 of 14 had partially occlusive thrombi (p less than 0.001 angiography vs angioscopy). After 2-hour occlusion and injection of thrombin into the injured segment, angiographic total (5 of 14), subtotal (3 of 14), or partial thrombotic occlusions (5 of 14) were created. Angioscopy showed similar results, except that total occlusions were classed as subtotal occlusions. After rotational thrombectomy, most arteries again appeared normal by contrast angiography (6 of 11) but none were angioscopically normal (p less than 0.006). Streptokinase, administered after rotational thrombectomy in seven arteries, normalized one 30% angiographic stenosis; there were no other angiographic changes. Findings with angioscopy were also unchanged. We conclude that in the diagnosis and treatment of intravascular thrombosis, angioscopy is generally more sensitive in the detection of intravascular thrombi, with the exception of total thrombotic occlusions. Angioscopy was uniquely effective in identifying subintimal flaps, which were never identified by angiography. In this model, streptokinase provided little or no additional thrombolytic benefit to mechanical thrombectomy alone.

Rotational thrombectomy in acute canine coronary thrombosis

We have developed a mechanical thrombolytic catheter which defibrinates a fresh intra-arterial thrombus by wrapping fibrin about its rotating shaft. Defibrination results in liquification of the thrombus and reperfusion of the thrombotically occluded vessel. In this study, we employed this catheter-based approach in dogs with coronary thrombosis to simulate possible clinical use in acute myocardial infarction. Total coronary thrombosis was generated in 11 dogs. Spontaneous reperfusion did not occur over a 30-minute control period. All vessels studied were initially totally thrombosed. After mechanical thrombolysis, there was a significant improvement in percent diameter stenosis from 100% to 28 +/- 26% (P less than 0.001). After thrombolysis, angiographically graded blood flow was normal in 9 of 11 arteries and was mildly delayed in 2 of 11. Complications included perforation of 2 vessels. We conclude that mechanical thrombolysis, with a rotating catheter, results in prompt reperfusion of the infarct vessel and significant improvement in distal blood flow. This approach, unlike angioplasty, removes the thrombus and might serve as an alternative to or supplemental form of mechanical thrombolysis.

Rotational endarterectomy in normal canine coronary arteries: preliminary report

Endarterectomy was performed in vivo using a high speed rotating abrasive-tipped catheter device in 11 normal canine coronary arteries. The device is designed to remove atheromatous material from diseased arteries by the abrasive action of its rotating tip. It was operated percutaneously from a femoral approach using conventional angioplasty guiding equipment. The rotating device was advanced over a guide wire from just beyond the tip of the guide catheter into the distal vessel. Six arteries were harvested immediately after endarterectomy and five were left in place for 7 +/- 2.8 days; in the latter group, the animals were maintained on a regimen of aspirin, 325 mg/day. Angiography before and after treatment demonstrated vessel patency in all cases. Caliper-measured luminal diameters were not significantly changed after endarterectomy. Histologic examination of pressure-fixed vessels showed extensive intimal loss and 20 to 30% loss of the internal elastic lamina. Medial damage was superficial and never exceeded 40% of the total medial thickness. There were no vessel perforations. Results of histologic study of the myocardium supplied by the treated vessels were normal without evidence of distal embolization or infarction. It is concluded that a high speed rotating abrasive device can be safely operated percutaneously in normal coronary arteries and results in minimal vessel damage and continued patency at 7 +/- 2.8 days.

Rotational atherectomy in atherosclerotic rabbit iliac arteries

PTCA is not technically possible in many patients with symptoms of coronary artery disease. In addition, atheroma is not physically removed by PTCA, and restenosis of the treated vessel is common. We have tested a new, rotating, abrasive-tipped angioplasty device in vivo in 13 atherosclerotic rabbit iliac vessels. Atherosclerosis was generated in rabbit iliac vessels by a 2% cholesterol diet combined with balloon endothelial injury for 10 weeks. The diseased vessels were then treated with the rotational atherectomy device. Before treatment, contrast angiograms demonstrated that initial percent diameter stenosis was 81% +/- 9%. After atherectomy, there was significant improvement, with residual 38% +/- 22% narrowing (p less than 0.001). One perforation resulted from distal guidewire manipulation, and one vessel was occluded by the device. Histologic examination demonstrated loss of portions of the diseased intima in all cases. Particles were produced for analysis in vitro by operating the atherectomy device in atherosclerotic rabbit aortas perfused with saline solution. Ninety-eight percent of the particles produced by the device were less than 10 micron in diameter. We conclude that this new rotational device can remove atheromatous material from diseased arteries in rabbits. Such a device may complement other angioplasty techniques and lead to wider application of catheter-based therapeutic interventions.

Mechanical thrombectomy: a comparison of two rotational devices and balloon angioplasty in subacute canine femoral thrombosis

In this study, two prototype rotational devices were compared to balloon angioplasty in a canine model of subacute arterial thrombosis. Radiographic 2- to 8-day-old total thrombotic occlusions were produced in 30 canine femoral arteries. A high-speed rotating device with a cutting tip was used in 18 arteries. Successful opening occurred in every case, with a residual percent diameter stenosis at 45 +/- 25%. Vessel perforation was seen in 6 of the 18 arteries. A noncutting rotational thrombectomy catheter was used in six arteries. Radiographic patency was established in two of six (residual stenosis 86 +/- 28%), with one perforation with the use of the noncutting thrombectomy catheter. Balloon angioplasty reestablished radiographic patency in three of six arteries (residual stenosis 77 +/- 2%). No perforations were seen with balloon dilation, but radiographic distal emboli were always observed. No radiographic emboli were observed with either of the rotational devices. We conclude that subacute arterial thromboses are easily opened with an abrasive-tipped rotating angioplasty device. Although perforations are relatively common with this prototype equipment, design changes may produce a clinically useful angioplasty device.

Pulmonary and systemic hemodynamic effects of nitrous oxide in infants with normal and elevated pulmonary vascular resistance

The hemodynamic response to 50% nitrous oxide was studied in 12 sedated but responsive infants in the intensive care unit following repair of their congenital heart disease. One-half of the infants studied had an elevated pulmonary vascular resistance index (PVRI greater than 3.5 Wood units). During mechanical ventilation with a fractional inspired O2 concentration (FIO2) of 0.5, hemodynamic parameters were measured after equilibration with 50% nitrogen and then after 50% nitrous oxide. The sequence was repeated once to assure reproducibility of the responses. Average heart rate decreased by 9%, mean arterial blood pressure decreased by 12%, and cardiac index decreased by 13% in both the elevated and normal PVRI groups each time nitrous oxide was given. Although statistically significant, these changes would not generally be clinically important except in infants with severely compromised cardiovascular reserve. In contrast, pulmonary artery pressure and PVRI were not significantly changed by administration of 50% nitrous oxide in either the group with normal PVRI or the group with preexisting elevated PVRI. We conclude that while these mild depressant effects of nitrous oxide on systemic hemodynamics in infants are similar to those previously reported in adults, in infants nitrous oxide does not produce the elevations in pulmonary artery pressure and pulmonary vascular resistance seen in adults.

Mechanical thrombolysis: a new rotational catheter approach for acute thrombi

We tested a new rotational thrombectomy catheter in acute thrombi formed both in vitro and in vivo. The catheter consisted of a rounded platinum tip, 0.025 inch diameter by 0.08 inch long, attached to a flexible steel guidewire supported by an external sheath. In vitro, the force required to penetrate thrombus was reduced fivefold by rotation of the catheter at 4000 rpm (0.75 +/- 1.2 g rotating vs 3.9 +/- 2.1 g static; p less than .001). Fibrin was extracted selectively from the thrombus and tightly wound about the shaft (3.8 +/- 1.5 mg rotating vs 0.75 +/- 0.4 mg static; p less than .001). In vivo, subtotal or complete thrombosis of the canine femoral artery was created. Thrombectomy by catheter rotation always produced tightly wound adherent fibrin on the catheter shaft. Angiographic patency was restored in 20 of 22 (91%) arteries, totally in seven of 22 (32%) and partially (greater than 20% increase in lumen diameter) in 13 of 22 (59%). There was one arterial perforation (5%). We conclude that this new mechanical catheter device reduces the force required to penetrate thrombus. Additionally, by winding fibrin about its shaft, the catheter is able to selectively remove the fibrin matrix of thrombus. Thus both the ease of initial thrombus recanalization as well as physical removal of thrombus are promoted by this new approach. Such an approach may be relevant to the treatment of recent thrombosis in acute myocardial infarction.

Anesthesia for hypoplastic left heart syndrome: use of high-dose fentanyl in 30 neonates

The anesthetic management of the first stage palliative surgical repair of hypoplastic left heart syndrome with a high-dose fentanyl (50 micrograms/kg)-pancuronium (0.14 mg/kg) anesthetic technique is described in 30 neonates. Previously this severe form of congenital heart disease carried a 100% rate of mortality. The pathophysiology that leads to this mortality is explained and related to the surgical procedure utilized for palliation. The major problem encountered intraoperatively was control of pulmonary blood flow. Management of the effect of anesthesia and intraoperative events on pulmonary blood flow was important because the rapid flux in pulmonary vascular resistance during the postnatal and perioperative period is the major destabilizing factor in these neonates. Ventricular fibrillation with surgical manipulation was a minor problem in the present series but was a major problem in an earlier series where a low dose narcotic-nitrous oxide technique was used. Ventricular fibrillation probably occurred due to the relative coronary insufficiency resulting from the anatomy present in this syndrome.

Blunting of stress responses in the pulmonary circulation of infants by fentanyl

After repair of congenital heart defects, stress responses in the pulmonary circulation of fourteen infants produced by a brief endotracheal suctioning procedure were studied before and after fentanyl (25 micrograms/kg). The total time of disconnection from the ventilator with suctioning (FIO2 1.0) was limited to no more than 15 sec to avoid alveolar hypoxia. Before fentanyl, marked increases occurred in mean pulmonary artery pressure and pulmonary vascular resistance index with suctioning, whereas only mild increases in heart rate and mean systemic arterial pressure occurred. All of these increases with suctioning were almost completely abolished by 25 micrograms/kg fentanyl. We conclude that suctioning or other broncho-carinal stimulation can produce a marked pulmonary vasoconstrictive response in infants, which is blunted by fentanyl. This response is separate from that produced by hypoxic pulmonary vasoconstriction associated with prolonged clinical suctioning procedures or with loss of airway.

Pulmonary and systemic hemodynamic responses to fentanyl in infants

Pulmonary and systemic hemodynamic responses to fentanyl were studied in 12 infants after repair of congenital heart defects. During controlled ventilation, hemodynamic responses to 25 micrograms/kg of fentanyl were measured. No significant changes were found in heart rate, cardiac index, mean pulmonary artery pressure, or pulmonary vascular resistance index 5 min after the fentanyl had been given. There were small but statistically significant decreases in mean arterial pressure and systemic vascular resistance index after fentanyl. We conclude that under the conditions of this study, pulmonary and systemic hemodynamics in infants are minimally altered by 25 micrograms/kg of fentanyl.

Pulmonary and systemic hemodynamic responses to ketamine in infants with normal and elevated pulmonary vascular resistance

Avoidance of ketamine has been recommended in children with pulmonary hypertension or with limited right ventricular reserve, despite absence of data about the effects of ketamine on pulmonary vascular resistance (PVR) in children. Ketamine has been associated with increased PVR in studies of adults; in these studies adults were spontaneously breathing through unprotected airways, despite ketamine's known effects of ventilatory depression and partial loss of airway. The authors measured pulmonary and systemic hemodynamic responses to ketamine during spontaneous ventilation in 14 intubated infants who were receiving minimal ventilatory support with an intermittent mandatory ventilation (IMV) of 4 at an FIO2 of 0.3-0.4. No significant changes were found in cardiac index (CI), pulmonary vascular resistance index (PVRI), or systemic vascular resistance index (SVRI) in a group of seven infants with normal PVRI or in another group of seven infants with preexisting increased PVRI. Results did not differ in infants receiving diazepam sedation. The authors conclude that ketamine has little effect on baseline hemodynamics in mildly sedated infants whose airway and ventilation are maintained; in particular, PVRI is little changed by ketamine administration in ventilated infants with either normal or increased baseline PVRI.

Anesthetic complications in surgery for congenital heart disease

Anesthetic complications in 500 consecutive operations for congenital heart disease were studied and their contribution to mortality and morbidity were assessed. The great majority of the cases were young and sick children in ASA Class III, IV, or V with complex congenital heart disease. Anesthetic mortality was zero and hospital mortality was 6.3%. Anesthetic complications occurred in 2% of the cases. Four major complications were seen, including two tension pneumothoraces, one episode of severe hypotension on induction, and a breathing circuit malfunction on induction leading to bradycardia and hypotension. Six minor complications included two cases of premature extubation that required reintubation postoperatively, one case of subglottic edema, airway obstruction from inadvertent tracheal insertion of an esophageal temperature probe, one corneal abrasion, and one case of erosion of the nasal ala secondary to a nasotracheal tube. Half of the complications were probably preventable, but the other half of the complications occurred despite specific attempts at their prevention.

Fentanyl- and sufentanil-oxygen-pancuronium anesthesia for cardiac surgery in infants

The safety and efficacy of fentanyl-oxygen (50 and 75 micrograms/kg) and sufentanil-oxygen (5 and 10 micrograms/kg) were studied in 40 infants undergoing repair of complex heart defects. When fentanyl or sufentanil was given simultaneously with pancuronium, induction of anesthesia was rapid and smooth with only mild and clinically insignificant hemodynamic changes. Hemodynamic responses to tracheal intubation were completely blocked, whereas hemodynamic responses to surgical incision and sternotomy were partially and variably blocked. Except for somewhat more effective blocking of responses to surgical stimulation by sufentanil, the effects of both narcotics were similar. No significant differences in effects were found between the two dose levels of either drug. Transcutaneous oxygen tensions increased with induction, intubation, and surgical stimulation with both fentanyl and sufentanil, even in cyanotic patients with right to left shunts. Fentanyl- and sufentanil-oxygen-pancuronium anesthesia were both safe and effective for cardiac surgery in infants. This study raises the question of possible beneficial effects of high dose fentanyl and sufentanil in blunting stress responses in the pulmonary circulation, a critical aspect of anesthesia and intensive care in the infant and neonate.

Subcutaneous fat necrosis of the newborn. A case report

A 3-day-old infant, born to a mother with preeclampsia, suffered intrauterine asphyxia and subsequently had multiple erythematous subcutaneous plaques and nodules. The clinical setting, the skin manifestations, and the histologic appearance of the lesions were diagnostic of subcutaneous fat necrosis of the newborn. Transient thrombocytopenia was noted with the appearance of the skin lesions, but returned to normal as the skin lesions spontaneously resolved.

The anaesthetic management of preterm infants undergoing ligation of patent ductus arteriosus

The authors reviewed the records of seventy preterm infants suffering from respiratory distress syndrome and, in most cases, refractory congestive heart failure, who underwent ligation of patent ductus arteriosus. The peri-operative management of these patients is described. The anaesthetic technique consisted of nitrous oxide and oxygen supplemented with a relaxant. All patients were ventilated manually with a humidified Jackson Rees system. The operations were performed in the main operating suite. There were no deaths during operation. The infants were protected from significant temperature fluctuations by various methods which are described. The overall survival rate of all preterm infants with respiratory distress syndrome. The management presented is considered acceptable to the infants, to the surgeons and to the anaesthetists.

Tricho-rhino-phalangeal syndrome

The major characteristics of tricho-rhino-phalangeal syndrome (TRPS) include shortened and deviated digits, a typical facies with a pear-shaped nose, a long philtrum and slow-growing, fine, sparse hair. Cone-shaped digital epiphyses are seen on x-ray. A few patients with TRPS are mentally retarded. Associated endocrine abnormalities have been reported. Autosomal dominant and recessive patterns of inheritance have been described with most cases showing a dominant mode of inheritance.

Intraoperative awakening for early recognition of possible neurologic sequelae during Harrington-rod spinal fusion

To permit early recognition of possible cord trauma due to spinal fusion with Harrington-rod instrumentation, 42 patients were awakened introperatively for testing voluntary motor function of the limbs. N2O-O2-curare and morphine were used for anesthesia in all patients. In 5 patients, who refused IV induction, halothane was given for induction only. Only 1 patient had any complaint referrable to being awakened intraoperatively. The awakening caused no displacement of Harrington rods in any patient. No neurologic sequelae were found.