Locoregional recurrence by molecular subtype after multicatheter interstitial accelerated partial breast irradiation: Results from the Pooled Registry Of Multicatheter Interstitial Sites research group

PURPOSE

To determine in breast tumor recurrence (IBTR) and regional nodal recurrence (RNR) rates for women treated with multicatheter interstitial accelerated partial breast irradiation.

METHODS AND MATERIALS

Data from five institutions were collected for patients treated from 1992 to 2013. We report outcomes of 582 breast cancers with ≥1 year of followup. Molecular subtype approximation was performed using estrogen receptor, progesterone receptor, Her2, and grade. The Kaplan-Meier method was used to calculate overall survival, IBTR, RNR, and distant recurrence rates. Univariate and multivariate Cox proportional hazard models were performed to estimate risks of IBTR and RNR.

RESULTS

With a median followup time of 5.4 years, the 5-year IBTR rate was 4.7% overall, 3.5% for Luminal A, 4.1% for Luminal B, 5.2% for Luminal Her2, 13.3% for Her2, and 11.3% for triple-negative breast cancer. Positive surgical margins and high grade were associated with increased risk for IBTR, as was Her2 subtype in comparison with Luminal A subtype. Other individual subtypes comparisons did not show a significant difference. Analysis of Luminal A vs. all other subtypes demonstrated lower IBTR risk for Luminal A (5-year IBTR 3.5% vs. 7.3%, p = 0.02). The 5-year RNR rate was 2.1% overall, 0.3% for Luminal A, 4.6% for Luminal B, 2.6% for Luminal Her2, 34.5% for Her2, and 2.3% for triple-negative breast cancer. RNR risk was higher for women with Her2 compared to the other four subtypes and for Luminal B compared to Luminal A subtype.

CONCLUSIONS

Molecular subtype influences IBTR and RNR rates in women treated with multicatheter interstitial accelerated partial breast irradiation.

Planned Neck Dissection after Definitive Radiotherapy or Chemoradiation for Base of Tongue Cancers

OBJECTIVES: The study goal was to analyze the role of planned neck dissection for squamous cell carcinoma of the base of the tongue treated with definitive radiotherapy or chemoradiation.

STUDY DESIGN, SETTING: We conducted a retrospective study of patients with squamous cell carcinoma of the base of the tongue undergoing planned neck dissection after definitive radiotherapy or chemoradiation.

RESULTS: Twenty-two of 41 (53.7%) patients had one to six positive residual lymph nodes after receiving definitive radiotherapy or chemoradiation. Neck control rates were 92.3% and 88.3% at two and five years, respectively. Three of 22 (13.6%) patients with pathological residual nodal disease had regional or locore-gional failures, compared with 1 of 19 (5.3%) patients with a pathologically complete response ( P = 0.39).

CONCLUSIONS: We observed a high incidence of pathologically residual lymph nodes after definitive radiotherapy or chemoradiation.

SIGNIFICANCE: Planned neck dissection following definitive radiotherapy or chemoradiation is highly effective in achieving regional control of squamous cell carcinoma of the base of the tongue.

High dose brachytherapy as monotherapy for intermediate risk prostate cancer

PURPOSE

We evaluated our retrospective, single institution experience with high dose rate brachytherapy as monotherapy for intermediate risk prostate cancer.

MATERIALS AND METHODS

Our cohort included 284 patients with intermediate risk prostate cancer, defined as clinical stage T2b/T2c, Gleason score 7 and/or prostate specific antigen 10 to 20 ng/ml, and 1-year minimum followup. Treatment was 2 high dose rate brachytherapy sessions at 3 fractions of 6.5 Gy each for a mean of 19 days. Prostate specific antigen failure was defined as nadir +2 ng/ml.

RESULTS

Mean followup was 35.1 months (median 31.9). Actuarial 5-year cause specific survival and clinical local control were 100%, distant-metastasis-free survival 98.8% and biochemical disease-free survival 94.4%. Clinical stage predicted biochemical disease-free survival. For stage T2a or less 5-year biochemical disease-free survival was 95.1% vs 100% for stage T2b and 77.4% for T2c (p = 0.012). Percent positive biopsy cores and prostate specific antigen nadir were also predictive. International Prostate Symptom Score results remained stable and potency was maintained in 82.6% of patients at 2 years. Pads were used for the first time after brachytherapy in 22 patients (7.7%), mostly for grade 1 incontinence (occasionally or less per week). Excluding patients with prior transurethral prostatectomy, stroke or tremor 2.5% used pads for the first time after treatment. No patient had urethral stricture. Radiation Therapy Oncology Group grade 1 rectal toxicity developed in 12 patients (4.2%) but not beyond grade 1.

CONCLUSIONS

High dose rate brachytherapy as monotherapy is safe and effective for patients with intermediate risk prostate cancer. We recommend caution for percent positive biopsy cores exceeding 75% or clinical stage T2c. Excluding such patients the 5-year biochemical disease-free survival rate was 97.5%.

American Brachytherapy Society recommends no change for prostate permanent implant dose prescriptions using iodine-125 or palladium-103

PURPOSE

In 2004, the American Association of Physicists in Medicine (AAPM) issued a report outlining recommended 125I and 103Pd datasets for consistency in calculating brachytherapy dose distributions. In 2005, to aid evaluating the clinical impact of implementing these datasets, the AAPM assessed the historical dependence of how prescribed doses differed from administered doses for 125I and 103Pd for permanent implantation of the prostate. Consequently, the American Brachytherapy Society (ABS) considered the nature of these changes towards issuing recommended dose prescriptions for 125I and 103Pd interstitial brachytherapy implants for monotherapy and standard boosts.

METHODS AND MATERIALS

An investigation was performed of the 2005 AAPM analysis to determine changes in administered dose while affixing prescribed dose using 2004 AAPM 125I and 103Pd brachytherapy dosimetry datasets for prostate implants. For 125I and 103Pd, administered dose would change by +1.4% and +4.2%, respectively. The biological and societal impact of changing prescribed dose was considered.

RESULTS

Based on the need for clinical constancy and in recognition of overall uncertainties, the ABS recommends immediate implementation of the 2004 AAPM consensus brachytherapy dosimetry datasets and no changes to 125I and 103Pd dose prescriptions at this time.

CONCLUSIONS

Radiation oncologists should continue to prescribe monotherapy doses of 145 Gy and 125 Gy for 125I and 103Pd, respectively, and standard boost doses of 100-110 Gy and 90-100 Gy for 125I and 103Pd, respectively.

Treatment of oropharyngeal squamous cell carcinoma with external beam radiation combined with interstitial brachytherapy

BACKGROUND

We reviewed the outcomes of oropharyngeal squamous cell carcinoma treated with external beam radiation and interstitial brachytherapy.

METHODS

Ninety patients with squamous cell carcinoma of the oropharynx were treated with interstitial brachytherapy at the University of Utah between 1984 and 2001. Seventy-two patients received external beam radiotherapy (EBRT) followed by brachytherapy boost, 11 had surgery followed by EBRT and brachytherapy, 4 had surgery and brachytherapy, and 3 were treated with brachytherapy alone. Median doses for EBRT and brachytherapy were 50 and 24 Gy, respectively.

RESULTS

Median follow-up after brachytherapy was 48.3 months for all patients. Five-year local control, disease-free survival, and overall survival were 76%, 61%, and 55%. For T1, T2, T3, and T4, 5-year local control rates were 83%, 79%, 79%, and 64%, respectively. Severe complications occurred in 13 patients, including 2 treatment-related deaths.

CONCLUSIONS

EBRT combined with interstitial brachytherapy provide good local control rates for locally advanced oropharyngeal squamous cell carcinoma.

Protective effects of isoflurane pretreatment in endotoxin-induced lung injury

BACKGROUND

The concept of antiinflammatory effects of volatile anesthetics is well established in vitro and in some organ systems. Their protective role in lung injury, however, remains to be elucidated. The authors hypothesized that in the lung, isoflurane pretreatment may attenuate neutrophil infiltration and reduce endotoxin-induced injury.

METHODS

Male C57Bl/6 mice were exposed to aerosolized lipopolysaccharide. Neutrophil recruitment into the pulmonary vasculature and migration into the different lung compartments (interstitium and alveolar air space) were determined by flow cytometry. Capillary protein leakage, formation of lung edema, and concentration of the chemokines keratinocyte-derived chemokine (CXCL1) and macrophage inflammatory protein 2 (CXCL2/3) in bronchoalveolar lavage were compared in mice with or without isoflurane treatment (1.4% inspired for 30 min) at different times before and after endotoxin exposure.

RESULTS

Endotoxin inhalation induced significant neutrophil migration into all lung compartments. Isoflurane pretreatment attenuated both neutrophil recruitment into lung interstitium and alveolar space when given 1 or 12 h before or 1 h after lipopolysaccharide but not at 4, 6, or 24 h before endotoxin exposure. Isoflurane pretreatment 1 or 12 h before lipopolysaccharide also reduced protein leakage and pulmonary edema. Production of CXCL1 and CXCL2/3 in the bronchoalveolar lavage was reduced when isoflurane was given 1 h but not 12 h before lipopolysaccharide, suggesting different mechanisms for early and late protection.

CONCLUSION

Isoflurane pretreatment reduces acute lung injury when given 1 or 12 h before an endotoxin challenge or within the first hour of an already established inflammation.

The protective effect of protein kinase C and adenosine triphosphate-sensitive potassium channel agonists against inflammation in rat endothelium and vascular smooth muscle in vitro and in vivo

Volatile anesthetic pretreatment protects the vasculature from inflammation-induced injury via mechanisms involving the activation of adenosine triphosphate-sensitive potassium (K(ATP)) channels and/or protein kinase C (PKC). Therefore, we hypothesized that K(ATP) and PKC agonists may mimic the protective effects of volatile anesthetics in vitro and in vivo. In vitro, rat vascular smooth muscle cells (VSM) and aortic endothelial cells (AEC) were used to evaluate whether pretreatment with a K(ATP) agonist, cromakalim (CRK), or a PKC agonist, phorbol 12-myristate 13-acetate (PMA), decreases lipopolysaccharide (LPS)-induced cell injury. Cell survival was determined by trypan blue staining after 6 h. In vivo, rats received systemic LPS or saline with or without pretreatment with PMA or CRK. Mean arterial blood pressure, the response to endothelium-dependent (acetylcholine; ACH) and -independent (sodium nitroprusside) vasodilators, and arterial blood gases were determined after 6 h. Cell survival in VSM and AEC control cultures was more than 90%, which was not altered in the presence of PMA or CRK, whereas LPS significantly decreased cell survival. PMA (0.1-10 microM) significantly attenuated the LPS-induced decrease in cell survival by 28%-37% in VSM and 39%-53% in AEC, and CRK (1 mM) increased cell survival by 24% in VSM and 22% in AEC. In vivo, PMA and CRK pretreatment had no significant effect on measured variables in control rats. LPS decreased mean arterial blood pressure and vasodilation to ACH and sodium nitroprusside and caused hypoglycemia. PMA, but not CRK, increased ACH-dependent vasodilation (46%) at 6 h, but neither agonist altered the other detrimental effects of LPS. In conclusion, PKC and K(ATP) agonists appear to protect AEC and VSM cells against inflammation in vitro, but the systemic administration of PKC and K(ATP) agonists appeared to exert minimal or no protection in our in vivo model.

Isoflurane pretreatment supports hemodynamics and leukocyte rolling velocities in rat mesentery during lipopolysaccharide-induced inflammation

We hypothesized that the protective effects of isoflurane (ISO) pretreatment on the vasculature may be attributed, in part, to altered leukocyte-endothelial interactions. Rats were anesthetized with pentobarbital and then randomized into four groups: control, ISO-control (pretreatment with 30 min of 1.4% ISO), lipopolysaccharide (LPS; 10 mg/kg IV), and ISO-LPS (ISO pretreatment and then LPS). The mesentery was prepared for intravital videomicroscopy. Mean arterial blood pressure (MAP), along with microcirculatory variables that included postcapillary venular and arteriolar blood flow velocity and leukocyte dynamics (number of rolling and adherent leukocytes and individual rolling leukocyte velocities), were measured hourly (baseline and at 0-4 h). In LPS rats, ISO pretreatment significantly (P < 0.05) attenuated the decrease in MAP at 2 and 4 h after LPS and increased leukocyte rolling velocities after 2-4 h. Four hours after LPS, leukocyte rolling velocities were >200% more rapid (63.7 +/- 27.6 microm/s versus 19.8 +/- 6.4 micro m/s) in ISO-LPS versus LPS rats. In control rats, ISO pretreatment had no effect on MAP or leukocyte rolling velocities but increased the number of rolling leukocytes. ISO pretreatment had no effect on arteriolar and postcapillary venular blood flow velocity in LPS rats or leukocyte adherence in LPS or control rats. In conclusion, ISO pretreatment supported hemodynamics and increased leukocyte rolling velocities but did not alter the number of rolling or adherent leukocytes in the mesenteric microcirculation during LPS-induced inflammation.

IMPLICATIONS

Isoflurane pretreatment supported hemodynamics and increased leukocyte rolling velocities in the mesenteric microcirculation during lipopolysaccharide-induced inflammation. Faster rolling velocities may reduce the incidence of inflammation by decreasing leukocyte-endothelial interactions and cellular injury.

Isoflurane pretreatment inhibits lipopolysaccharide-induced inflammation in rats

BACKGROUND

Previous studies have indicated that volatile anesthetic pretreatment protects cells from inflammation; therefore, the authors hypothesized that pretreatment with isoflurane may attenuate the hemodynamic and pathologic changes to the vasculature that are associated with inflammation.

METHODS

Rats received intravenous lipopolysaccharide or saline placebo with and without pretreatment with isoflurane (1.4% for 30 min immediately before lipopolysaccharide). Mean arterial pressure (MAP) and response to endothelium-dependent (acetylcholine) and -independent (sodium nitroprusside) vasodilators were assessed hourly for 6 h. Tumor necrosis factor-alpha concentrations, arterial blood gases, and vascular histology were also determined.

RESULTS

Lipopolysaccharide decreased MAP and vasodilation to acetylcholine and sodium nitroprusside. Lipopolysaccharide also caused acidosis, endothelial swelling, and endothelial detachment from the smooth muscle. Isoflurane pretreatment prevented the decrease in MAP for 5 h and attenuated the decrease at 6 h. Pretreatment increased the vasodilation to acetylcholine in lipopolysaccharide rats to control concentrations but had no effect on sodium nitroprusside. In control rats, isoflurane pretreatment increased the response to acetylcholine and sodium nitroprusside but had no effect on MAP. Isoflurane pretreatment prevented the acidosis and endothelial damage to mesenteric and aortic vessels, and attenuated the increase in tumor necrosis factor-alpha associated with lipopolysaccharide-induced inflammation.

CONCLUSION

Pretreatment with 30 min of isoflurane attenuated the decrease in MAP and endothelium-dependent vasodilation, the acidosis, the increase in tumor necrosis factor-alpha, and the damage to the vascular endothelium associated with lipopolysaccharide-induced inflammation in rats. This study suggests that isoflurane pretreatment may protect the vasculature during inflammation.

A double-blind study to evaluate the safety of recombinant human hemoglobin in surgical patients during general anesthesia

OBJECTIVE

To evaluate recombinant human hemoglobin (rHb1.1) in patients undergoing surgery involving general anesthesia; examine rHb1.1 for toxicity, including renal dysfunction and hypertension; and measure plasma concentrations of rHb1.1 over time.

DESIGN

Prospective, double-blinded, randomized, placebo-controlled study.

SETTING

University medical center hospital.

PARTICIPANTS

Eighteen patients having surgery under general anesthesia.

INTERVENTIONS

One of 4 escalating doses of rHb1.1 or normal saline (control) was administered by continuous infusion to patients receiving general anesthesia for elective surgical procedures. Total rHb1.1 doses ranged from 4.7 to 25.6 g.

MEASUREMENTS AND MAIN RESULTS

Clinical and laboratory data, including vital signs monitoring, hematology (white blood cell and reticulocyte count, hemoglobin, hematocrit, erythrocyte sedimentation rates, and coagulation values), renal function (serum creatinine and blood urea nitrogen), hepatic function (mean and indirect bilirubin), pancreatic function (serum amylase and lipase), and antibodies (IgG and IgM) to Escherichia coli protein, were collected at specified intervals for 7 days after infusion of rHb1.1. No serious adverse events occurred. The most frequently observed clinical event occurred during the first 24 hours after infusion and was primarily associated with surgery and anesthetic administration. A slightly higher incidence of hypertension, symptoms suggestive of pyrogenicity, mildly elevated total and indirect bilirubin, and elevated pancreatic enzymes was observed in rHb1.1 treatment groups when compared with control. Hypertension resolved within 7 hours, and laboratory values returned to normal levels by day 7.

CONCLUSION

Although the elevations in pancreatic enzymes seen in some rHb1.1-treated patients remain unexplained, the safety profile of rHb1.1 appears to be acceptable. These results support the continued clinical evaluation and development of rHb1.1.

Excitatory amino acid receptor antagonist 2APH may improve local CBF during cerebral ischemia in cats

BACKGROUND

The present study was designed to investigate in a focal cerebral ischemia model the influence of 2APH, a competitive NMDA receptor antagonist, on the cerebral blood flow of cat cortex, given intravenously before cerebral ischemia.

METHODS

Thirty-four male cats weighing 2.5 to 3.5 kg were anesthetized with halothane and then randomly assigned to either control or experimental group. In the experimented group 18 cats were treated with 2APH and in the control group 16 cats were given saline 10 min before middle cerebral artery occlusion (MCAO). Cortical blood flow (CBF), determined by laser Doppler ultrasound flowmetry, was measured 1 h, 2 h, 3 h, 4 h and 5 h after occlusion. Infarct volume was calculated by summing up the areas in each stained brain section after the experiment.

RESULTS

There was a significant difference in the infarct volume of cortex between the 2APH group and the saline control group (P < 0.05). Moreover, we did notice an apparent decrease of the infarct volume in basal ganglia area when 2APH was given (P < 0.01). The total infarct volume was significantly smaller in the group treated with 2APH after MCAO as compared with the saline control group (P < 0.01).

CONCLUSIONS

The data from the present experiment suggest that NMDA antagonists may not only antagonize the neurotoxic effect of excitatory amino acid on ischemic neuron but also improve the CBF of ischemic brain.

Gene therapy: a novel method for the treatment of myocardial ischemia and reperfusion injury--mini-review

Myocardial ischemia and reperfusion injury (MI/R) represents important sequelae of clinical events. Historically, a number of approaches including, surgical intervention, pharmacological therapy and physical exercise regimes have been prescribed for the treatment of patients with cardiovascular disease. Recently, however, attention has focused upon more novel approaches using gene-based therapies to treat cardiovascular and MI/R. This mini-review will examine the role that heat shock proteins (HSP), in particular the HSP70 family, and the antiapoptotic protein Bcl-2 play in myocardial protection. Also examined in this review are several techniques including adenovirus and Japan-Liposomal method for delivering genes into the myocardium.

Administration of sevoflurane and isoflurane prior to prolonged global ischemia improves heart function in isolated rat heart

BACKGROUND

The Langendorff model was used to determine whether pretreatment with sevoflurane, isoflurane, or ischemic preconditioning (IP) could protect the myocardium of rats against global ischemia.

METHODS

After 15-min perfusion, each isolated heart was assigned to (1) CONTROL GROUP: no pretreatment, (2) Sevoflurane group: 20-min exposure of 1.7% sevoflurane prior to ischemia, (3) Isoflurane group: exposure of 1.4% isoflurane prior to ischemia, or (4) IP group: two 5-min ischemic periods separated by 5-min perfusion. Following pretreatment, each heart was exposed to 20-min global normothermic ischemia followed by 60-min reperfusion. Heart rate (HR), left ventricular end-diastolic pressure (LVEDP), left ventricular developed pressure (LVDP), HR x LVDP, left ventricular contractility (+dLVP/dt), and coronary flow were recorded continuously. Myocardial damage was assessed by hematoxylin and eosin (H&E) staining.

RESULTS

No significant differences (P > 0.05) in hemodynamic variables were recorded among the four groups before the experiment. After ischemia during reperfusion, sevoflurane, isoflurane and IP pretreated hearts recovered left ventricular function significantly better than control hearts. After 60-min reperfusion, +dLVP/dt recovered to 6.84 +/- 1.06%, 23.3 +/- 4.80%, 42.3 +/- 3.16%, and 59.6 +/- 5.75% of baseline values respectively for control, sevoflurane, isoflurane and IP groups. HR x LVDP recovered to 8.9 +/- 1.7%, 27.9 +/- 6.42%, 38.7 +/- 2.78%, and 59.6 +/- 3.98% respectively. H&E staining supported the hemodynamic data in that hearts pretreated with sevoflurane, isoflurane and IP showed significantly less ischemic damage when compared to control hearts.

CONCLUSIONS

Our study shows pretreatment with sevoflurane or isoflurane provided moderate protection to the isolated heart against prolonged periods of global ischemia.

Radiation therapy for tracheobronchial amyloidosis

A 67-year-old man presented with localized tracheobronchial amyloidosis involving the distal trachea and the right-sided airways. The disease caused right middle lobe collapse and threatened the right upper and lower lobes. A variety of bronchoscopic methods, including Nd:YAG laser resection, dilation, and stenting, were used as temporizing methods. External beam radiation therapy, considered because of disease progression, caused a measurable local response. Radiation therapy should be considered as a treatment option for localized tracheobronchial amyloidosis causing airway obstruction.

Effects of dobutamine, norepinephrine and epinephrine on intramucosal pH and hemodynamics of dogs during endotoxic shock

This study assessed the effects of dobutamine (DOB), epinephrine (EPI) and norepinephrine (NE) on gastric tissue oxygenation indicated by gastric intramucosal pH (pHi) and hemodynamics in dogs subjected to endotoxic shock. Twenty-four dogs were assigned to four groups of 6 dogs each: endotoxin without catecholamine and endotoxin with DOB, or EPI or NE. Endotoxic shock was induced by intravenous injection of 3 mg/kg of E. coli over 1 min, with an additional 3 mg/kg over the next 2 hrs. Dogs were resuscitated with normal saline to maintain pulmonary capillary wedge pressure (PCWP) near baseline levels. Catecholamines were infused at 0.1, 0.4 and 1.6 micrograms/kg/min (EPI and NE) and 2.5, 5.0 and 10.0 micrograms/kg/min (DOB) for 30 min at each rate. After 2 hrs of endotoxemia, mean arterial pressure (MAP) and cardiac index (CI) and oxygenation delivery index (DO2I) for all dogs decreased by 46.5%, 43.9% and 15.1% respectively, while pHi decreased from 7.47 to 7.10. Endotoxemia increased blood lactate by 142%. Following fluid resuscitation, EPI (1.6 micrograms/kg/min) further increased lactate by 178% (1.22 to 3.4 mmol/L). No correlation was found between tonometry pHi and lactate (R2 = 0.003), pHi and pHa (R2 = 0.231), pHi and DO2I (R2 = 0.056) nor between intramucosal PCO2 and PaCO2 (R2 = 0.005). pHi did not reflect the improvements in cardiovascular hemodynamics observed following administration of catecholamines. NE improved MAP, CI and DO2I whereas DOB produced similar effects as NE but further reduced SVR. EPI produced similar effects as NE. DOB, NE and EPI further decreased pHi. EPI significantly (P < 0.05) increased blood lactate levels more than DOB and NE.

Effects of dobutamine, epinephrine and norepinephrine on the hemodynamics of dogs during hemorrhagic shock

BACKGROUND

The present study examined how effective epinephrine (EPI), norepinephrine (NOR) and dobutamine (DOB) were for resuscitating dogs subjected to hemorrhagic shock (HS).

METHODS

Dogs (n = 42) were randomly assigned to seven test groups: EPI, NOR and DOB infusion with and without HS, and HS dogs with no catecholamine. Following baseline measurements, the dogs were bled to a mean arterial blood pressure of 40 mmHg. After 3 h, the shed blood was reinfused. EPI and NOR (0.1, 0.4 and 1.6 micrograms/kg/min) and DOB (2.5, 5.0 and 10.0 micrograms/kg/min) were given and the dog allowed to stabilize for 30 min. Hemodynamic and blood gas data were obtained at 6 time points (control, shock, resuscitation and after catecholamine infusion).

RESULTS

There was no significant difference in myocardial performance (dP/dt) between the respective shocked and unshocked groups after blood resuscitation. In dogs without catecholamine infusion, CO and SvO2 continued to decline whereas SVR increased. DOB (2.5 to 10.0 micrograms/kg/min) with and without shock improved CO, LV dP/dt, SVR and SvO2. EPI did not further improve CO or SvO2 at infusion rates above 0.1 microgram/kg/min (with and without shock). NOR did not improve SvO2 at any infusion rate (with and without shock) and did not improve CO until the infusion rate was at 0.4 microgram/kg/min (without shock).

CONCLUSIONS

This study advocates the use of both volume replacement therapy and DOB for resuscitation of HS dogs.

Monitoring body-core temperature from the trachea: comparison between pulmonary artery, tympanic, esophageal, and rectal temperatures

INTRODUCTION

We designed an endotracheal tube (ETT) for acquiring body-core temperature from the trachea. This ETT had two temperature sensors, one attached to the inside surface of the cuff, the other mounted on the ETT shaft underneath the cuff. The ETT was evaluated in vitro and in dogs to determine: 1) optimal position of temperature sensors and 2) the responsiveness, accuracy, and resistance to ventilatory artifacts.

METHODS

In vitro. An artificial trachea assessed the response-time and accuracy of ETT temperature sensors to abrupt temperature changes and ventilatory flow-rates. In vivo. Body temperature in 5 dogs was lowered to approximately 26 degrees C then elevated toward 39 degrees C using a heat exchanger during carotid-jugular bypass. ETT temperature measurements were compared simultaneously with those from the artificial trachea (in vitro) or from the pulmonary artery, tympanic cavity, esophagus, and rectum of dogs using dry and humidified gas.

RESULTS

Cuff temperature sensor responded quickly and accurately to temperature changes and was less prone than the tube sensor to ventilatory and humidity artifacts. During carotid-jugular bypass, in vivo tube and cuff mean temperatures averaged 1.4 degrees C and 0.36 degree C lower, respectively, than pulmonary artery temperatures. There were no statistical differences (P > 0.05) between cuff temperatures and those measured from the pulmonary artery, tympanic cavity, esophagus, and rectum. Heating and humidifying the inspiratory gas of dogs with a water-bath humidifer or heat moisture exchanger (HME) had minimal effects on the cuff temperature sensor. An in-line HME increased in vivo tube temperature from baseline values by 1.13 +/- 0.80 degree C, while cuff temperature increased by 0.21 +/- 0.24 degree C.

CONCLUSION

The cuff of the ETT is a reliable site for measuring body-core temperature in intubated patients.

Dosimetry and treatment planning of complex electron arc therapy

Electron arc therapy has been primarily utilized for treatment of the post-mastectomy chest wall. Its clinical usefulness and benefits have been proven. Casting procedures and blocking techniques have been discussed. We have successfully applied electron arc therapy to the treatment of the nasal cavity and associated nodal regions. When compared to the chest wall, the smaller radii and pronounced irregularity of the surface anatomy of the facial region presents multiple new dosimetric and treatment planning challenges. We will discuss these challenges, along with those encountered in the casting procedures and reproduction of patient characteristics required for the execution of this treatment. Many aspects of dosimetry were utilized in unique ways to produce the treatment plans, cast and bolus needed. Due to the insertion of bolus into the nostrils, a unique hollow bite block was constructed to allow patient respiration during treatment. Film dosimetry was used to verify computer predictions and to compare this electron arc treatment technique with alternative fixed electron beam techniques. The potential benefits and difficulties of this technique will be discussed.

Monitoring normal and aberrant electrocardiographic activity from an endotracheal tube: comparison of the surface, esophageal, and tracheal electrocardiograms

INTRODUCTION

We designed an endotracheal (ET) tube with orthogonally spaced ECG cuff electrodes. This ET tube was evaluated in dogs and sheep to determine (1) whether ECGs recorded from our tube were sufficient to make accurate clinical decisions concerning heart rate and rhythm; and (2) whether metallic cuff electrodes in direct contact with the trachea could induce mucosal burn injury during episodes of defibrillation.

METHODS

Using experimental animals, we obtained ECGs from their tracheae and compared our findings with ECGs obtained from surface and esophageal electrodes. The electrical activity of the heart was modified by increasing the depth of anesthesia, occluding the left coronary artery, and administering beta-adrenergic drugs. Before the dogs were euthanized, they were subjected to episodes of transthoracic and intrathoracic defibrillation at energy levels of 200 to 400 J. A postmortem pathological examination of the trachea was performed to determine the incidence of mucosal burn injury.

RESULTS

Tracheal electrocardiography provided valid information on heart-rate monitoring and certain morphology profiles. The R-R, PR, QRS, and QT intervals measured from the trachea had a correlation of 1.0, 0.96, 0.83, and 0.98, respectively, when compared with the same intervals obtained from surface electrodes. Two tracheae subjected to intrathoracic defibrillation at > 300 J revealed evidence of minor burn injury. Some localized epithelium loss was displayed in all tracheae; we attributed this to tracheal intubation.

CONCLUSION

Tracheal electrocardiography may be useful in trauma patients who require intubation where injury precludes placement of chest ECG electrodes.

Computed tomography treatment planning in IR-192 brachytherapy in the head and neck

Brachytherapy dose prescription and treatment planning lag behind the state-of-the-art for external beam therapy. As altered fractionation of external beam therapy improves patient outcome in head and neck cancer, there will be an increased need to compare the two radiotherapy techniques. Currently, implant techniques and dose prescription documentation are not uniform, dose prescription to a target volume is subjective, and implant quality is poorly understood and not routinely assessed. All contribute to a lack of scientifically rigorous brachytherapy clinical trials. Studies designed to combine tumor imaging and dosimetry data are important in the evolution of brachytherapy treatment planning. Head and neck implants, which often require nonparallel, arching, or looping source carriers for all but small tumors in order to encompass the target volume adequately, were used to evaluate the clinical utility and feasibility of computed tomography as a treatment planning tool in brachytherapy. Following placement of plastic afterloading tubes under general anesthesia, orthogonal radiographs with dummy sources in the afterloading tubes are obtained as customary for source localization. With the patient in the same position, axial CT scans are obtained with the dummy seeds still in place for treatment planning. The implant physician, using data from the pre-treatment diagnostic CT scan, outlines target areas on sequential images creating a 3-dimensional target volume. By superimposing anatomic data with isodose curves one can objectively define implant parameters important in clinical trials analysis. These include minimum target absorbed dose, implant uniformity, and treatment to target volume ratio. The results of the first 10 patients are presented and implications of these data regarding the analysis of implant technique, implant quality, and implant optimization are discussed. The technique as performed is laborious but practicable in the clinical research setting of head and neck implant. Further research efforts should improve, simplify, and objectify brachytherapy and hasten the time when rigorous multi-institutional brachytherapy trials will be reality.

Comparison of tidal ventilation and high-frequency jet ventilation before and after cardiopulmonary bypass in dogs using two-dimensional transesophageal echocardiography

This study compared the use of high-frequency jet ventilation (HFJV) and tidal ventilation (TV) in a group of dogs with induced global myocardial ischemia before and after cardiopulmonary bypass. Transesophageal echocardiography was used to determine whether HFJV with its lower airway pressures could improve cardiac performance. The surgical procedure was separated into four study periods: closed chest before bypass, open chest before bypass, open chest after bypass, and closed chest after bypass. During each of these study periods, the dogs were randomly ventilated with alternate periods of TV and HFJV to maintain the PaCO2 at 34.3 +/- 3.3 mm Hg (mean +/- SEM). Cardiac output, stroke volume, systemic mean blood pressure, left ventricular ejection fraction, left ventricular end-diastolic volume, left ventricular dP/dt, left ventricular stroke work, and expiratory volumetric flows were higher during HFJV, whereas airway pressures and pulmonary vascular resistance were lower. Increases in cardiac output and stroke volume during HFJV were due to a combination of improved left ventricular contractility indicated by increased LV dP/dt and increased left ventricular end-diastolic volume accompanying decreased airway pressures. These data indicate that HFJV with its lower airway pressure is associated with significantly less impairment of cardiovascular function than TV in dogs with induced global myocardial ischemia.

Carotid thrombosis following neck irradiation

Therapeutic irradiation may accelerate atherosclerosis, increasing the risk of vascular stenosis or occlusion several to many years following radiation. However, intimal damage following irradiation may result earlier in thrombosis without stenosis. This report discusses three cases of carotid occlusion that occurred within 3 years of moderate dose irradiation. Angiographic studies showed that occlusion occurred in the absence of atherosclerotic stenosis. A review of the literature supports the conclusion that people who receive neck irradiation are at risk not only for the delayed development of diffuse atherosclerosis but also for thrombotic occlusion within months to several years. We suggest that patients who develop neurological symptoms or signs following neck irradiation, regardless of age, dose of radiation, or interval since radiation, should be evaluated for carotid or vertebral artery disease.

Definitive radiation therapy in bile duct carcinoma

Between 1980 and 1985, 24 patients with primary adenocarcinoma of the bile duct were treated with various combinations of surgery, biliary intubation, external irradiation, and transcatheter brachytherapy. Seventy-five percent of tumors were in the proximal bile ducts. Ten patients received no or only palliative radiation, Group 1, whereas 14 patients received definitive courses of radiation (4 by external beam irradiation, 2 by transcatheter irradiation, and 8 by both modalities), Group 2. Survival in Group 1 and Group 2 was significantly different (p less than 0.005) with median survivals of 2.0 and 12.8 months, respectively. This result may be in part due to differences in treatment and in part due to selection bias because the series is small, uncontrolled, and retrospective. Median survival of the 8 patients treated with combined modalities was 13.2 months (range 7.4-30.3) with 4 patients alive 8.7 to 16.2 months, 3 without cholangiographic evidence of disease. Complications of therapy were common, including bacterial sepsis (58%), cholangitis (38%), gastrointestinal bleeding (46%), intra or extrahepatic abscesses (33%), and recurrent biliary obstruction (25%). Cholangitis, hemorrhage, abscesses, and ulcers appeared more frequently in definitively treated patients, whereas recurrent biliary obstruction was absent in this group and frequent in Group 1. Differences in complication rates between groups were not statistically significant. Early diagnosis and management usually reversed a downhill clinical course in patients with abscess and hemorrhage. Both surgical and percutaneous techniques of biliary decompression, the usual initial form of therapy in bile duct cancer, are associated with frequent and serious complications. Although many of our complications may have derived from biliary decompression, it is possible that definitive treatment may have increased the frequency of serious complications.

Computer-controlled anesthesia delivery system

A prototype Computer-Controlled Anesthesia Delivery System (CCADS) has been developed. The CCADS uses proportional, integral, and derivative (PID) software algorithms to control the delivery of oxygen, anesthetic agent,and nitrous-oxide (N2O) via the computer feedback control of precision mass-flow controller devices. The CCADS was evaluated in a group of seven dogs during 4 hours of closed-circuit enflurane N2O anesthesia. Throughout the 4-hour monitoring period, the CCADS maintained the animals' inspired oxygen concentration (FIO2), end-tidal enflurane concentration, and breathing circuit volume to within +/- 0.20, +/- 0.10 volume %, and +/- 30 ml/min (+/- 1 SD), respectively, of the desired values. The interactive software allowed selective graphic display of the 10-breath averaged data parameters, or modification of FIO2, end-tidal enflurane concentration, and breathing circuit volume, whenever animal re-evaluation during an anesthesia procedure was necessary.

Candidate products of avian myeloblastosis virus oncogene region produced by in vitro translation of genomic RNA

Avian myeloblastosis virus (AMV) genomic RNA was translated in vitro to identify the AMV transforming gene (myb) product(s). Full-length RNA yielded, in addition to the expected Pr76gag, a gag-related product of 92,000 daltons which did not appear to be a gag-oncogene fusion protein. Subgenomic AMV RNA in vitro translation, nonstructural products (specific for AMV) were of 54,000, 49,000 and 34,000 daltons. Based on their sizes and similar peptide maps for the smaller two proteins, it is proposed that they derive from the myb region of AMV.

Monitoring anesthetic vapor concentrations using a piezoelectric detector: evaluation of the Engstrom EMMA

The Engstrom anesthetic gas analyzer (EMMA) was evaluated to determine the reproducibility, response time, gas interference, water vapor dependence, and sensitivity. The analyzer also was evaluated clinically in 20 children undergoing orthopedic surgery. Difference between the analyzer output and anesthetic gas standard (reproducibility) ranged from 0.013 +/- 0.008 vol % to 0.018 +/- 0.018 vol %. Response times decreased from 710 ms at 5 l X min-1 to 149 ms at 30 l X min-1. Nitrous oxide caused an offset of +0.11 +/- 0.007 vol %. Water vapor caused positive offsets of 0.25 +/- 0.044 vol %, 0.51 +/- 0.027 vol %, and 0.80 +/- 0.037 vol % at 25 degrees C, 30 degrees C, and 34 degrees C, respectively. The analyzer reproducibly measured dry gas concentrations, but compensation had to be made for water vapor when measuring wet gases. The analyzer's usefulness for end-tidal monitoring was questioned because of its slow response time and its sensitivity to water vapor.

Feedback control of enflurane delivery in dogs--inspired compared to end-tidal control

A technique was studied for the rapid induction of anesthesia in a closed rebreathing circuit using feedback control of end-tidal enflurane concentration. This technique was compared to anesthetic induction using a constant inspired concentration. In one group of seven dogs, end-tidal enflurane concentration was maintained at 2.0%. Electronic feedback control automatically decreased the inspired concentration from a maximum of 3.7% to 2.1% during a 4-hr period. In the second group of seven dogs, the inspired enflurane concentration was 2.0% throughout the study. There was no statistically significant difference between the two groups with regard to enflurane uptake, heart rate, blood pressure, or cardiac output. Enflurane uptake was higher in the first group only during the first 6 min after induction. The induction technique that used feedback control to automatically adjust the inspired enflurane concentration appeared to have no adverse cardiovascular effects beyond those present during an induction using a constant inspired concentration.

Uptake of enflurane: a study of the variability between patients

Variability in the uptake of enflurane has been studied using a computer-controlled "overpressure" induction technique in 23 paediatric patients. The administration of enflurane was feedback-controlled and its uptake measured using a closed anaesthesia delivery system with the end-tidal concentration held constant at 2.0%. The standard deviation in uptake was greater than 28% of the average uptake during the first 60 min of enflurane anaesthesia. The uptake at 60 min ranged from 5.7 to 16.2 ml min-1 m-2. The variability in enflurane uptake between patients was best minimized by normalizing the patient's uptake according to body surface area. Although the average total volume of enflurane calculated according to a model compared well with the average total volume given in our study, the variation in uptake between patients indicated that a single model cannot be used to deliver anaesthesia to a varied patient population. The system described in this paper demonstrates the feasibility of using feedback control of fresh gas delivery for the automatic control of an "overpressure" induction technique.