Short-duration hyperoxia causes genotoxicity in mouse lungs: protection by volatile anesthetic isoflurane.

High concentrations of oxygen (hyperoxia) are routinely used during anesthesia, and supplemental oxygen is also administered in connection with several other clinical conditions. Although prolonged hyperoxia is known to cause acute lung injury (ALI), whether short-duration hyperoxia causes lung toxicity remains unknown. We exposed mice to room air (RA or 21% O2) or 60% oxygen alone or in combination with 2% isoflurane for 2 h and determined the expression of oxidative stress marker genes, DNA damage and DNA repair genes, and expression of cell cycle regulatory proteins using quantitative PCR and Western analyses. Furthermore, we determined cellular apoptosis using TUNEL assay and assessed the DNA damage product 8-hydroxy-2'-deoxyguanosine (8-Oxo-dG) in the urine of 60% hyperoxia-exposed mice. Our study demonstrates that short-duration hyperoxia causes mitochondrial and nuclear DNA damage and that isoflurane abrogates this DNA damage and decreases apoptosis when used in conjunction with hyperoxia. In contrast, isoflurane mixed with RA caused significant 8-Oxo-dG accumulations in the mitochondria and nucleus. We further show that whereas NADPH oxidase is a major source of superoxide anion generated by isoflurane in normoxia, isoflurane inhibits superoxide generation in hyperoxia. Additionally, isoflurane also protected the mouse lungs against ALI (95% O2 for 36-h exposure). Our study established that short-duration hyperoxia causes genotoxicity in the lungs, which is abrogated when hyperoxia is used in conjunction with isoflurane, but isoflurane alone causes genotoxicity in the lung when delivered with ambient air.

Rate-Dependent Left Bundle Branch Block in an Ambulatory Surgery Patient: A Case Report.

A 52-year-old woman, ASA II (American Society of Anesthesia classification II) scheduled for cholecystectomy in an ambulatory center, exhibited a wide-complex tachycardia with ectopy on the monitor after induction with propofol and succinylcholine. Blood pressure remained stable; amiodarone was administered for presumed ventricular tachycardia. A 12-lead electrocardiogram (ECG) showed a new left bundle branch block (LBBB) at 98 beats per minute (bpm), which resolved when the heart rate slowed. Surgery was postponed, and both the LBBB and ectopy recurred frequently during the next 24 hours in the intensive care unit, particularly at heart rates >90 bpm. Troponins were normal, and the patient was diagnosed with a rate-dependent LBBB and cleared for surgery.

Use of Prothrombin Complex Concentrate for Warfarin Reversal Before the Performance of an Epidural Blood Patch in a Patient With Cortical Vein Thrombosis and Subdural Hematoma: A Case Report.

Compared to conventional therapy, several studies with prothrombin complex concentrate (PCC) have recently demonstrated its superior efficacy in rapidly replacing vitamin K-dependent factors for patients with life-threatening hemorrhage. We present a novel use of PCC in a patient with intracranial hypotension, who had received warfarin for treatment of cortical vein thrombosis. However, after anticoagulation, she proceeded to develop bilateral subdural hematomas with descent of cerebellar tonsils. Given the possibility of an occult dural puncture during labor analgesia, an epidural blood patch was performed after administration of PCC and normalization of coagulation parameters, with prompt improvement of the patient's headache.

Biphasic response of checkpoint control proteins in hyperoxia: exposure to lower levels of oxygen induces genome maintenance genes in experimental baboon BPD.

Breathing high concentrations of oxygen (hyperoxia) causes lung injury and is associated with lung diseases such as bronchopulmonary dysplasia (BPD), respiratory distress syndrome and persistent pulmonary hypertension of the newborns. Hyperoxia (95-100 %O2) causes DNA damage and growth arrest of lung cells and consequently cells die by apoptosis or necrosis. Although supplemental oxygen therapy is clinically important, the level and duration of hyperoxic exposure that would allow lung cells to reenter the cell cycle remains unclear. We hypothesized that cells exposed to lower concentrations of hyperoxia will retain the capacity to enter cell cycle when recovered in room air. We employed varying concentrations of oxygen (21-95 %) to determine the response of lung cells to hyperoxia. Our results indicate that cells were growth arrested and failed to reenter the cell cycle when exposed to greater than 60 % oxygen. Cell cycle checkpoint proteins were increased in a biphasic manner, increasing until 70 % oxygen, but declined in greater than 90 % oxygen. Microarray analysis shows that there is significant decrease in the abundance of Cdks 6-8 and retinoblastoma protein (Rb), p107 and p130 in exposure to 90 % oxygen for 48 h. We further tested the effect of clinically relevant as needed oxygen [(pro-re-nata (prn)] in premature infant (125-days and 140-days) baboon model of BPD. The microarray results show that 6 or 14d PRN oxygen-exposed animals had induced expression of chromosomal maintenance genes (MCMs), genes related to anti-inflammation, proliferation, and differentiation.

Do residency applicants know what the ACGME core competencies are? One program's experience.

PURPOSE: To determine the degree of knowledge that medical students applying to the St. Luke's-Roosevelt Hospital Center anesthesiology residency program had regarding the core physician competencies mandated by the Accreditation Council for Graduate Medical Education. METHOD: As a part of the department's annual resident-selection process, in the fall of 2008, 193 interviewed fourth-year U.S. MD-degree medical students applying to the St. Luke's-Roosevelt Hospital Center anesthesiology program were given a brief, written questionnaire to determine their knowledge of the six core physician competencies. The instructions for completing the instrument were standardized and delivered to the applicants by one of the program directors. RESULTS: A total of 193 applicants completed the interview questionnaire. Seventy-six had no knowledge of any of the physician competencies, and only three were able to correctly identify all six. CONCLUSIONS: While this research is an observation of only one set of applicants to one residency program, if the findings are applicable to other programs and specialties, that suggests that medical schools and residency program directors should develop methods for increasing competency awareness among medical students.

Pulmonary artery flow patterns after the Fontan procedure are predictive of postoperative complications.

OBJECTIVE: Pulmonary artery (PA) flow reversal has been associated with poor outcome in patients with atriopulmonary (APC) and total cavopulmonary connection (TCPC) lateral tunnel (LT) Fontan modification. The authors studied PA flow after TCPC in relation to the incidence of early Fontan outcome and complications. DESIGN: A prospective observational study. SETTING: A university hospital. PARTICIPANTS: Pediatric patients undergoing a Fontan procedure. INTERVENTION: Nineteen patients were studied. PA flow was measured by pulse-wave Doppler during the surgery after chest closure. Patients were divided into 2 groups according to patterns of PA flow: group 1, positive (biphasic or continuous flow), and group 2, negative (with flow reversal component). The postoperative complications were recorded. MEASUREMENTS AND MAIN RESULTS: There were no deaths or reoperations for Fontan takedown. Ten patients had positive and 9 had negative flow. There were no differences between groups regarding age, weight, length of procedure, and cardiopulmonary bypass. The chest tube drainage in patients with negative flow was significantly longer than those in the positive-flow group (8.3 +/- 7.0 days in the negative-flow group v 2.8 +/- 1.7 days in the positive-flow group, p = 0.03). The total number of complications was higher in the negative-flow group compared with the positive-flow group (3.0 +/- 1.3 v 1.2 +/- 0.6, p = 0.003). The differences between groups in terms of pediatric intensive care unit and/or hospital length of stay did not reach statistical significance, possibly because of the low number of patients. CONCLUSION: PA flow pattern appears to be predictive of the length of postoperative chest tube drainage and the number of postoperative complications.

Thoracic paravertebral block for implantable cardioverter-defibrillator and laser lead extraction.

Implantable cardioverter defibrillators (ICDs) are routinely placed in the cardiac electrophysiology laboratory. Previously, these procedures were performed in the operating room during general anesthesia. In recent years, electrophysiologists have been performing these procedures using local anesthetics in conjunction with intravenous sedation. We report a case in which thoracic paravertebral blocks with mild sedation were successful for infected ICD and laser lead extraction. Randomized, controlled trials are required to determine whether thoracic paravertebral block with sedation is more effective than local anesthesia with sedation in providing adequate anesthesia for ICD placement and extraction.

Assessment of cerebral oxygen balance during deep hypothermic circulatory arrest by continuous jugular bulb venous saturation and near-infrared spectroscopy.

OBJECTIVE: The purpose of this study was to compare jugular venous bulb saturation (SjvO(2)) and regional cerebral oximetry (rSO(2)) by near-infrared spectroscopy (NIRS) during procedures with deep hypothermic circulatory arrest (DHCA). DESIGN: Prospective observational study. SETTING: Academic hospital. PARTICIPANTS: Patients undergoing aortic reconstructive surgery with DHCA from July 2001 to January 2005. INTERVENTION: The authors examined cerebral oxygenation by continuous NIRS monitoring and by blood gas analysis of intermittently sampled jugular bulb blood (SjvO(2)). Data were obtained during various stages of the procedure in 29 patients. NIRS measurements were compared with SjvO(2). MEASUREMENTS AND MAIN RESULTS: NIRS and SjvO(2) trends were similar. Overall, cerebral venous oxygen saturation obtained from NIRS was lower compared with SjvO(2) (p < 0.05), especially during periods of low temperature. The mean correlation between NIRS and SjvO(2) was 0.363, and the individual correlations varied from -0.11 to 0.91. The low mean correlation was because of a high degree of variability in the NIRS data between patients. CONCLUSION: It was concluded that NIRS does not closely correlate with SjvO(2) in this patient population. Cerebral oximetry measured by NIRS could not replace jugular bulb saturation as an intraoperative marker of adequate metabolic suppression.

Anesthetic management of staged separation of craniopagus conjoined twins.

We present a case of successful separation of craniopagus conjoined twins. The procedure was staged to permit each child to develop adequate independent cerebral venous drainage and to prevent deleterious, perioperative cerebral edema. Surgical hemorrhage, blood product delivery, and hemodilution were minimized.

The postoperative cardiovascular arrest of a 5-year-old male: an initial presentation of Duchenne's muscular dystrophy.

Anesthesia may be administered to patients with Duchenne's muscular dystrophy, but cases are reported in which apparently healthy children suffer hyperkalemic cardiac arrest. We present the case of a 5-year-old boy whose muscular dystrophy was discovered following a fatal, perioperative cardiac arrest in the postanesthesia care unit.

Caudal anesthesia in pediatric cardiac surgery: does it affect outcome?

OBJECTIVE: The purpose of this study was to examine the influence of caudal anesthesia on outcomes (pediatric intensive care unit [PICU] length of stay, hospital length of stay, ventilatory time, early extubation rate) in pediatric patients undergoing congenital heart disease repair requiring cardiopulmonary bypass (CPB). DESIGN: Retrospective. SETTING: University teaching hospital. PARTICIPANTS: Pediatric patients undergoing surgery to treat congenital heart disease between 1999 and 2002. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Thirty-four patients with atrial septal defect (ASD), 37 with ventricular septal defect, and 46 with tetralogy of Fallot (TOF) were included in the analysis. No differences were found in preoperative and intraoperative data between caudal and noncaudal group for each disorder. There was no difference between caudal and noncaudal groups in PICU and hospital stay. A statistically significant difference was found in the postoperative ventilatory time in patients with ASD and TOF between caudal and noncaudal groups. The early extubation rate was higher in the TOF caudal group compared with the noncaudal group. CONCLUSIONS: This retrospective study demonstrated that postinduction placement of caudal anesthesia does not affect PICU or hospital length of stay. A well-controlled prospective study is needed to confirm these findings.

Utility of ultrasound-guided central venous cannulation in pediatric surgical patients: a clinical series.

BACKGROUND: Central venous cannulation can be particularly difficult in pediatric patients. Central line placement is associated with many well-known complications. While ultrasound-guided techniques are well established, the majority of central venous catheters are placed using landmark guidance. This retrospective study compares the safety and efficacy of ultrasound guidance vs landmark guidance in central venous cannulation of pediatric cardiac surgery patients. METHODS: The medical records of 149 pediatric patients undergoing cardiac surgery over 3-year period were reviewed. Patients were classified into two cohorts based on whether central venous cannulation of the internal jugular vein was performed by ultrasound or landmark guidance. Overall success and traumatic complication rates were compared between the two groups. Additionally, comparisons between the groups were made to determine if patient size or age affected the success rate of either approach in different manner. RESULTS: Patients in the ultrasound-guided (n = 47) and the landmark-guided (n = 102) groups were similar with respect to age, weight, and surgical procedure for which central venous access was indicated. The overall success rate for cannulation of the internal jugular vein was 91.5% in the ultrasound-guided group and 72.5% in the landmark-guided group (P = 0.010). But in the subgroup of children under 1 year of age, success rate was 77.8% in ultrasound group and 60.9% in landmark group (P = 0.44); in children under 10 kg in weight, success rate was 80% in ultrasound group and 56.7% in landmark group (P = 0.19). There were no significant differences in the rate of traumatic complications between the two methods. CONCLUSIONS: The overall success of internal jugular vein cannulation for pediatric cardiac surgery is significantly improved with the use of ultrasound guidance, without a significant difference in traumatic complications. However, mostly children above 1 year of age or 10 kg of weight experience advantages of ultrasound technique.