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Clare Savage

Publications and source records attributed to Clare Savage.

16 recordsLinked to original sources
PubMed2004

St Thomas Hospital Cardioplegia #2 fails to suppress slow reaction pacemaker cell electrical activity.

BACKGROUND: Inadequate right atrial myocardial preservation during cardioplegic arrest may promote postoperative supraventricular arrhythmias (SVA). We determined (1). if oxygenated St. Thomas Hospital Cardioplegia #2 (STH2) alone causes slow reaction pacemaker cell (SR) quiescence; and (2). if hypothermia, higher [K(+)], lower [Ca(2+)], and verapamil in STH2 suppresses SR electrical activity. MATERIALS AND METHODS: A glass microelectrode recorded SA node SR membrane action potentials (AP) in rabbits (n = 23, 1.93 +/- 0.45 kg) randomized to normothermic STH2 (33 degrees C, n = 6), hypothermia (20 degrees C, n = 4), hypothermic STH2 (22 degrees C, n = 3), lower calcium STH2 (n = 3), higher potassium STH2 (n = 4), and STH2 plus Verapamil (n = 3). RESULTS: Normothermic STH2 depressed SR action potential amplitude and action potential duration (APD), but did not completely suppress action potential generation. Hypothermia alone prolonged APD and sinus cycle length and suppressed SR AP. STH2 with hypothermia (to 20 degrees C) completely suppressed propagating AP and STH2 plus 0.04 Ca(2+) mEq/L inhibited SR AP generation. STH2 plus 30 mEq K(+) and STH2 plus 2.5 mmol/L verapamil failed to generate SR AP. CONCLUSION: STH2 cannot prevent SA node SR myocardial cells from low-amplitude AP autogeneration above 21 degrees C. STH2 with 30 mEq/L K(+), STH2 with 0.02 mEq/L Ca(2+), and STH2 plus 2.5 mmol/L verapamil can arrest AP generation in SR and potentially prevent postoperative SVA.

Animals↗
PubMed2004

Transthoracic image-guided biopsy of lung nodules: when is benign really benign?

PURPOSE: A pathologic diagnosis of malignancy by image-guided transthoracic fine needle aspiration (FNA) with or without (+/-) core biopsy is definitive. However, a benign diagnosis of a lung nodule by FNA +/- core biopsy presents a management dilemma of resection for confirmation versus follow-up imaging and/or medical treatment. We propose three separate pathologic categories of benign diagnosis after FNA +/- core biopsy: (i) benign specific (ie, aspergillosis); (ii) benign nonspecific (ie, fibrosis); and (iii) nondiagnostic. Our goal was to define when to resect "benign" nodules to avoid an unacceptably high false-negative rate. MATERIALS AND METHODS: All FNA +/- core biopsy diagnoses considered nonmalignant at a single institution from 1996 to 2001 were retrospectively reviewed for management and outcomes by radiologic or pathologic follow-up. RESULTS: Ninety-five of 836 total cases with FNA +/- core biopsies over the 5-year period were identified as nonmalignant and had complete pathologic or radiologic follow-up. Twenty-one of 95 had a benign specific diagnosis; all were true-negative for malignancy on radiologic (n = 17) or surgical (n = 4) follow-up. The remaining 74 had either benign nonspecific (n = 53) or nondiagnostic (n = 21) diagnoses. Seven of 53 benign nonspecific specimens (13%) and six of 21 nondiagnostic specimens (29%) were malignant at excisional biopsy or radiologic follow-up. Sixteen of 95 (17%) had a postprocedural pneumothorax requiring a chest tube. CONCLUSION: Transthoracic FNA +/- core biopsy may yield a nonmalignant diagnosis as (i) benign specific, (ii) benign nonspecific, or (iii) nondiagnostic. Diagnosis-directed medical management is recommended for a benign specific diagnosis. Additional diagnostic studies, repeat biopsy, or resection is necessary for benign nonspecific and nondiagnostic biopsy results as a result of an unacceptably high rate of malignancy.

Algorithms↗
PubMed2003

The effect of the Varian amorphous silicon electronic portal imaging device on exit skin dose.

Measurements have been made of the increase in exit surface dose resulting from backscattered radiation generated by the Varian amorphous silicon electronic portal imaging device (EPID). An increase of < or = 14% was demonstrated at both 6 MV and 10 MV, in a manner which suggests that backscatter from the EPID acts to re-establish electronic equilibrium at the exit surface, normally absent in the build-down region. The magnitude of this effect was influenced by field size, measurement depth and exit surface to EPID distance. Assuming typical constraints of portal imaging frequency and geometry, the results suggest that EPID generated backscatter is unlikely to alter the frequency or severity of exit skin reactions. However, the results do suggest that a limit on the minimum separation between the EPID and the exit surface should be set, and that similar investigations should be made for other EPID models.

Equipment Failure Analysis↗
PubMed2003

Imaging of bilateral ureteropelvic junction laceration from blunt trauma.

Bilateral ureteropelvic junction (UPJ) injury from blunt abdominal trauma is rare, with only seven previously reported cases, all of which were complete avulsions. Early and delayed computed tomography (CT) for visualization of the nephrographic and excretory renal phases, respectively, is essential to distinguish parenchymal from collecting system injury. Once UPJ injury is detected by CT, differentiation between laceration and avulsion is mandatory since laceration is treated nonoperatively, whereas avulsion requires surgical repair. In addition to CT, intravenous pyelography (IVP) or retrograde pyelography may be required for full characterization of the injury. Retrograde pyelography may permit better opacification of the ureters than IVP, enabling the urologist to determine whether stent placement is necessary. We report the first case of bilateral UPJ laceration secondary to blunt abdominal trauma and the imaging studies necessary to make the diagnosis.

Journal Article↗
PubMed2002

Salinoma window technique for mediastinal lymph node biopsy.

Computed tomographic-guided transthoracic needle biopsy can access virtually all mediastinal lymph node stations, but is limited by the potential for pneumothorax and bleeding. To avoid these possible complications, the extrapleural "salinoma" technique was used for computed tomographic-guided mediastinal biopsies in 15 patients. Sampling methods were coaxial (8), tandem (5), and single pass (2). Diagnostic yield was 93% with no significant bleeding or pneumothorax. The salinoma technique permits biopsy of deep mediastinal lesions to stage pulmonary malignancies, while providing a technique that limits complications.

Biopsy, Needle↗
PubMed2002

Thoracic imaging in the ICU. Interventional radiology.

Radiology in the intensive care unit (ICU) patient is dominated by plain x-rays, with noteworthy findings prompting further imaging and possible intervention. This chapter discusses interventional and minimally invasive techniques used to treat pleural, mediastinal and pulmonary parenchymal problems commonly encountered in the ICU.

Biopsy, Needle↗
PubMed2002

Postthoracotomy pain management.

The following techniques appear efficacious in controlling postthoracotomy pain and reducing the amount of systemic opioids consumed: continuous intercostal blockade, paravertebral blockade, and epidural opioids and/or anesthetics. The combination of thoracic epidural opioid and local anesthetic is very effective at relieving postthoracotomy pain, however, considerable experience is required for insertion of the thoracic epidural catheter and postoperative respiratory monitoring. Intercostal and paravertebral catheters can be inserted intraoperatively under direct visualization, to reduce complications of insertion. One-time intraoperative intercostal blockade may effectively reduce postoperative pain in the first day, but is not a practical long-term method for postthoracotomy pain. The effectiveness of interpleural analgesia, even with proper technique, appears inferior to epidural and other regional techniques. We have incorporated the principles outlined in this review into our general thoracic surgery protocol, as detailed in Fig. 1. Every patient is assessed preoperatively for epidural catheter placement. Contraindications include low platelet count (< 100,000), abnormal coagulation profile, medicinal anticoagulation (aspirin and nonsteroidal anti-inflammatories are not contraindications), bony spinal abnormalities, or neurological disorders. The T5/6 interspace is our preferred level, but T10 can work well with an increased dose of bupivacaine. Upon completion of the muscle sparing, minimal-access thoracotomy, we close the wound and perform a percutaneous intercostal nerve block (two ribs above and three below the incision). We then use patient-controlled epidural analgesia, with a basal infusion of bupivacaine and hydromorphone. To supplement inadequate or nonfunctioning epidurals, intravenous patient-controlled opioids are added. When choosing an approach to postthoracotomy pain management, the thoracic surgeon and anesthesiologist must consider the following: (1) the physician's experience, familiarity and personal complication rate with specific techniques; (2) the desired extent of local and systemic pain control; (3) the presence of contraindications to specific analgesic techniques and medications; and (4) availability of appropriate facilities for patient assessment and monitoring postthoracotomy. Refinements in surgical technique including limited or muscle-sparing thoracotomy, video-assisted thoracoscopic surgery (VATS) and robotic surgery may lessen the magnitude of postthoracotomy pain. We encourage all thoracic surgeons to be knowledgeable of available techniques and maintain a protocol to generate a database for periodic assessment of safety and efficacy.

Algorithms↗
PubMed2002

Mediastinal transthoracic needle and core lymph node biopsy: should it replace mediastinoscopy?

STUDY OBJECTIVES: Primary assessment of mediastinal lymph nodes (N2 or N3) for staging lung cancer by transthoracic needle with or without core biopsy. Mediastinoscopy only performed after FNA failed to yield a diagnosis. DESIGN AND SETTINGS: A retrospective study in a university setting. PATIENTS: Eighty-nine patients with mediastinal lymphadenopathy (> 1.5 cm in short-axis diameter) by CT. METHODS: Mediastinal transthoracic fine-needle aspiration (FNA) with or without core biopsy was performed prior to mediastinoscopy in 89 patients with mediastinal lymphadenopathy (lymph node > 1.5 cm in short-axis diameter) or masses by CT. RESULTS: Mediastinal transthoracic FNA was used alone in 39 of 89 patients, or with core biopsy in 50 of 89 patients. Mediastinal transthoracic FNA with or without core biopsy was diagnostic in 69 of 89 patients (77.5%) for cancer cell type, sarcoidosis, or caseating granulomas with or without tuberculosis. Transthoracic FNA with or without core biopsy of nodal stations (total, 94 biopsies) judged readily accessible by mediastinoscopy (n = 59) included paratracheal (n = 56) and highest mediastinal (n = 3); those more difficult (n = 26) included subcarinal (n = 20) and aorticopulmonary window (n = 6); and those impossible (n = 9) included paraesophageal and pulmonary ligament (n = 6), parasternal (n = 2), and para-aortic (n = 1). Innovative lung protective techniques for CT-guided biopsy access windows included "iatrogenic-controlled pneumothorax" (n = 10) or saline solution injection creating a "salinoma" (n = 11). Pneumothorax was detected in only 10% with a "protective" technique but 60% when traversing lung parenchyma. Transthoracic FNA with or without core biopsy failed to yield a diagnosis in 20 of 89 patients (22.5%); all then underwent mediastinoscopy, with 11 of 20 procedures (55%) diagnostic for cancer, and 9 of 20 procedures diagnostic of benign diagnosis or no cancer. CONCLUSION: Transthoracic FNA with or without core biopsy accesses virtually all mediastinal nodal stations is diagnostic in 78% of cases with mediastinal adenopathy or masses, and should precede mediastinoscopy in the staging of lung cancer or workup of mediastinal masses.

Adult↗
PubMed2002

Malignant eccrine acrospiroma with metastasis to the parotid.

Malignant eccrine acrospiromas are rare. Clinically, they resemble other cutaneous lesions. A high index of suspicion must be maintained in cases of histologically benign eccrine acrospiromas for three reasons: (1) malignant transformation can occur, (2) the presence of both benign and malignant tissue can lead to a false-negative diagnosis if only the benign component is obtained in the biopsy specimen, and (3) benign-appearing tumors can recur locally or metastasize. The primary treatment is wide local excision with or without lymph node dissection. The efficacy of adjuvant chemotherapy and radiation therapy requires further investigation. We describe a case of malignant eccrine acrospiroma in an 80-year-old man, and we review the literature on this tumor, with emphasis on the differential diagnosis.

Acrospiroma↗
PubMedDate not supplied

Percutaneous retrieval of chronic intravascular foreign bodies.

To evaluate the feasibility of intravascular retrieval of chronic foreign bodies, we retrospectively reviewed an 8 year experience (1993-2001) of percutaneous retrieval of chronically retained intravascular foreign bodies (n = 6). In 6 of 6 cases (4 catheter fragments, 2 guidewires), 5-90 days elapsed before retrieval via the femoral or internal jugular vein. Under fluoroscopy, we determined the foreign body's course, position and size. A guidewire was advanced through a multipurpose catheter to the foreign body. The multipurpose catheter was replaced with a gooseneck snare catheter and the snare advanced to grasp and remove the foreign body. Percutaneous retrieval was successful in all 6 cases. One patient experienced mild hemoptysis, which resolved within 24 hr of observation. No patient experienced long-term sequelae. Given the potential life-threatening complications from intravascular foreign bodies and the low complication rate from percutaneous retrieval, we recommend extraction of the foreign body even if it is asymptomatic in the chronic setting (> 24 hr).

Adolescent↗
PubMedDate not supplied

Arterio-venous CO2 removal (AVCO2R) perioperative management: rapid recovery and enhanced survival.

Percutaneous arteriovenous CO2 removal (AVCO2R) uses a simple arteriovenous (A-V) shunt for near-total CO2 removal that allows significant reductions in minute ventilation. We critically reviewed our algorithm-directed perioperative anesthesia management in our LD40 ovine smoke-burn injury model of acute respiratory distress syndrome (ARDS) treated with AVCO2R. General anesthesia is required for: (1) Vascular access followed by ARDS model development by smoke insufflation (36 breaths) plus 40% TBSA III degrees burn with mechanical ventilation. Induction: 12.5 mg/kg im ketamine and 4% halothane by mask, then intubation. Maintenance: 1.0-2.5% halothane in 100% O2; (2) When PaO2/FiO2 < 200 (48-52 h), sheep randomized to the AVCO2R (n = 8) or SHAM (n = 8) procedure. Induction: 66% N2O and 5% isoflurane in balance O2. Maintenance: 1.5-2.5% isoflurane in 100% O2 for AVCO2R, cannulation (10F carotid artery, 14F jugular vein); (3) Postop, both groups had algorithm-directed ventilator management, identical heparin (ACT > 300 s), fluid, and analgesia management. All sheep met criteria for ARDS, survived anesthesia, and were standing by 0.5-5 h. There were no complications attributable to anesthesia. The absence of anesthesia-related complications allows model development for outcomes studies for ARDS in general and AVCO2R specifically.

Algorithms↗
PubMedDate not supplied

High-frequency percussive ventilation with systemic heparin improves short-term survival in a LD100 sheep model of acute respiratory distress syndrome.

We undertook an assessment of high-frequency percussive ventilation (HFPV) and systemic heparin on survival in our LD100 sheep model of smoke/burn-induced acute respiratory distress syndrome (ARDS). This was a prospective controlled outcomes study in a large animal critical care laboratory. ARDS was induced in 13 sheep by a combination of 48 cotton smoke breaths and 40% full-thickness cutaneous burn (LD100) followed by mechanical ventilation (15 ml/kg tidal volume). After meeting ARDS criteria (PaO2/FiO2 < 200), the sheep were divided into high-frequency percussive ventilation (HFPV; n = 7) or volume-controlled mechanical ventilation (VCMV; n = 6) groups. Both groups received systemic heparin to achieve an ACT 180-300 seconds. HFPV was managed with the Volumetric Diffusive Respiration Ventilator (Percussionaire Corp., Sandpoint, ID). The VCMV group was managed with up to 10 ml/kg tidal volume. Arterial blood gases and ventilator settings were monitored every 6 hours after onset of ARDS. HFPV did not affect sheep hemodynamics. Survival 84 hours after smoke and burn injury was significantly greater in the HFPV (7/7, 100%) compared with the VCMV group (3/6, 50%, P < .05). PaCO2 was significantly greater in VCMV group at 36, 48, and 72 hours after smoke and burn injury. PaO2/FiO2 after 36 hours of smoke and burn injury in the HFPV group was improved compared with the VCMV group, but no statistical difference was found. In the VCMV group, peak airway pressure was decreased to 19.7 +/- 2.2 cm H2O at 36 hours from 29 +/- 2.8 at 24 hours as the tidal volume changed from 15 ml/kg to 10 ml/kg and then gradually increased to 39 +/- 5.6 cm H2O at 72 hours. In the HFPV group, peak inspiratory pressure kept constant at a level of 30 cmH2O. In our smoke/burn-induced LD100 sheep model of ARDS, volume-controlled mechanical ventilation with systemic heparin achieved a 50% survival whereas HFPV with systemic heparin achieved 100% survival at 60 hours after the onset of ARDS.

Animals↗
PubMedDate not supplied

Toward ambulatory arteriovenous CO2 removal: initial studies and prototype development.

Extracorporeal arteriovenous carbon dioxide removal (AVCO2R) using percutaneous cannulae and a low resistance gas exchanger achieves near total CO2 removal, allowing lung rest and potentially improving survival. AVCO2R, redesigned to allow ambulation, has potential as treatment for severe chronic obstructive pulmonary disease or rehabilitation before lung transplant. The purposes of this study were to 1) determine the optimal ambulatory access for AVCO2 removal and 2) develop a prototype Ambulatory-AVCO2R gas exchanger. Initially, reinforced Gore-Tex 6 mm (two) and 8 mm (four) grafts were anastomosed to sheep carotid arteries and jugular veins as a loop in parallel to the cranial circulation to determine blood flow capabilities. Blood flow was 100-150 ml/min with a 14 gauge dialysis needle, and transected 6 mm Gore-Tex grafts achieved 500-900 ml blood flow, whereas transected 8 mm grafts achieved up to 2000 ml/min flow. The polytetrafluoroethylene (PTFE) loops were then connected to our newly developed ultra low resistance pumpless gas exchanger for ambulatory AVCO2R. The average pressure gradient across the prototype Ambulatory-AVCO2R gas exchangers (n = 5) was 2.8 +/- 0.8 mm Hg, and mean CO2 removal was 104.8 +/- 14.0 ml/min, with an average blood flow of 900 ml/min. We conclude that an 8 mm Gore-Tex reinforced graft arteriovenous loop supplies ample blood flow for our new ultra low resistance Ambulatory-AVCO2R to achieve near total CO2 removal.

Animals↗
PubMedDate not supplied

Short term performance evaluation of a perfluorocopolymer coated gas exchanger for arteriovenous CO2 removal.

A new perfluorocopolymer coating for micropore hollow fiber gas exchangers was developed to improve gas exchange, reduce plasma leakage, and reduce blood-surface interactions. The present authors evaluated gas exchanger performance using this new coating in a prospective, randomized, controlled, unblinded, large animal model of CO2 retention. Adult sheep (30-40 kg), under general anesthesia, underwent cannulation of the carotid artery (12 F) and jugular vein (14 F). The perfluorocopolymer coated (n = 5) and uncoated (n = 5) gas exchangers were attached to an arteriovenous CO2 removal (AVCO2R) circuit. Blood gases, CO2 removal, and hemodynamics were monitored throughout the 6 hour study. Average CO2 removal was 107.6 +/- 15.6 ml/min (coated) vs. 93.0 +/- 13.9 ml/min (uncoated; p < 0.01). PaCO2 and CO2 removal for both coated and uncoated did not deteriorate significantly over the study. Average AVCO2R blood flow was 1,130 +/- 25 ml/min (coated) versus 1,101 +/- 79 ml/min (uncoated; p = not significant). Likewise, cardiac output and AVCO2R blood flow did not change over the duration of the study. No significant differences in the pressure gradient or resistance between devices (coated, 6.89 +/- 1.14 mm Hg/L/min; uncoated, 6.42 +/- 0.23 mm Hg/L/min) was noted. The authors concluded that the new perfluorocopolymer coated gas exchanger improved CO2 removal without compromising hemodynamics in an acute performance evaluation.

Animals↗