An established extracorporeal membrane oxygenation protocol promotes survival in extreme hypothermia.

BACKGROUND: Historical reports indicate that active rewarming with extracorporeal membrane oxygenation (ECMO) can salvage a patient after hypothermic cardiac arrest. We created a protocol that includes ECMO for extreme hypothermia to guide rewarming of the hypothermic patient. METHODS: A retrospective review of the ECMO rewarming protocol (2004-2006) was conducted. RESULTS: The active rewarming protocol is a flowchart that is available on our hospital intranet and can be accessed in the trauma bay. A severely hypothermic patient triggers the activation of a TRAUMA ONE-OP ECMO response. During the 2-year period, there were 5 activations of the system and 4 children were placed on ECMO. Two of the 4 were dramatically salvaged and eventually discharged neurologically intact. All 5 children were found pulseless at the scene before transport. The average time from the injury occurrence to arrival was 94 minutes (range, 41-181 minutes). Mean cardiopulmonary resuscitation time was 78.2 minutes (range, 37-152 minutes). The mean core temperature on arrival was 25.4 degrees C (range, 20.4 degrees C-28.6 degrees C). The average time from arrival to ECMO cannulation was 25.5 minutes (range, 16-37 minutes). CONCLUSION: A preemptive strategy for the severely hypothermic patient provides an organized approach and prompt response. Expeditious rewarming can make the difference in an opportunity for survival.

Meconium staining of amniotic fluid correlates with intestinal peel formation in gastroschisis.

Several studies in animal models demonstrate that peel formation in gastroschisis is due to the accumulation and activation of intestinal waste products (IWP) in the amniotic fluid. We reviewed our recent experience with gastroschisis and asked the following questions: First, does staining of the bowel and amniotic fluid with IWP correlate with intestinal peel formation? Second, what prenatal ultrasound findings indicate that peel formation is occurring in utero? Over two years, 16 neonates were treated for gastroschisis; twelve had been diagnosed by prenatal ultrasound and followed closely. Patients were grouped based on the presence of IWP in the amniotic fluid at the time of delivery (staining or no staining), and outcomes were reviewed. All neonates in the staining group (n=7) had a fibrinous peel present at the time of birth whereas a peel was absent in all neonates in the no-staining group (n=9). Matting of the bowel was seen by prenatal ultrasound in four patients in the staining group (0/8 in the no-staining group) and correlated with peel formation (Fisher's exact test p =0.007). Primary closure was done in 14 of the infants, and two required silo closure. In neonates with gastroschisis, staining of the amniotic fluid and bowel serosa with IWP correlated with intestinal peel formation. The ultrasound findings of matting correlated with both peel formation and staining with IWP. These results suggest that spillage of IWP into the amniotic fluid is one of the factors in peel formation in gastroschisis. Identification of matting of the bowel by prenatal ultrasound indicates formation of a peel.

Testing the effectiveness of converting patients to long-acting antianginal medications: The Quality of Life in Angina Research Trial (QUART).

OBJECTIVE: Our purpose was to test the hypothesis that converting patients with stable angina to long-acting antianginal medications would improve their functional status, symptom control, treatment satisfaction, and quality of life. METHODS AND RESULTS: A single-blind randomized trial of 100 patients with stable coronary artery disease was performed in the outpatient clinic of a Veterans Affairs Health System. Outpatients with chronic stable angina taking at least 2 antianginal medications were studied. Patients were randomized to one of two treatments: optimal adjustment of their usual antianginal medications or conversion to solely long-acting medications (long-acting diltiazem +/- nitroglycerin patches +/- atenolol) with subsequent optimization. The primary outcome was the 3-month change in Seattle Angina Questionnaire scores. Although no differences in physical limitation scores were noted, patients randomized to receive long-acting medications had improved symptom control (3-month improvement in anginal stability [19.1 vs 5.6, P =.02] and anginal frequency [17.8 vs 5.5, P =.006]), more treatment satisfaction (3-month improvement of 8.2 vs 3.0, P =.057), and better quality of life (3-month improvement of 11.2 vs 5.6, P =.09) compared with patients whose pretrial medications were optimized. The improvement in symptom control was statistically significant. CONCLUSION: Converting patients with chronic, stable angina to long-acting antianginal medications resulted in substantial improvements in symptom control with a trend toward better treatment satisfaction and quality of life.

Cardiovascular responses to facial cooling are age and fitness dependent.

PURPOSE: Aging of the cardiovascular system may be altered by differences in physical fitness. We investigated the cardiovascular responses to brief periods of facial cooling (5 degrees C) in 20 healthy men differing in age and aerobic fitness (VO2max). METHODS: Facial cooling was administered at rest in the supine position during 60-s quiet breathing to 6 fit young (FY; VO2max = 75.8 +/- 18 mL x kg(-1) x min(-1); 29 +/- 7 yr), 6 sedentary young (SY; VO2max = 36.0 +/- 2.2 mL x kg(-1) x min(-1); 27 +/- 3 yr), 6 fit old (FO; VO2max = 56.1 +/- 4.0 mL x kg(-1) x min(-1); 54 +/- 5 yr), and 6 sedentary old (SO; VO2max = 29.6 +/- 5.0 mL x kg(-1) x min(-1); 62 +/- 2 yr) volunteers. The following were measured before and after facial cooling: heart rate (HR), mean arterial blood pressure (MAP), pressure-rate product (PRP), and M-mode echocardiographically determined left ventricular internal dimensions, peak circumferential shortening (peak V(CF)), and ejection fraction (EF). RESULTS: Facial cooling produced a statistically significant bradycardia in all groups except for the SO whereas MAP was increased in the young groups but unchanged in the older groups. Pressure-rate product was significantly reduced in the FY, unchanged in the SY and FO, and significantly increased in the SO group. None of the groups showed a change in left ventricular dimensions, whereas only the SO group showed an increase in peak V(CF) (P < 0.05). CONCLUSIONS: These data suggest that endurance training and fitness level do not significantly alter cardiovascular responses to facial cooling in young men or physically fit older men. However, in older subjects, a sedentary lifestyle appears to be associated with an absent facial cooling reflex bradycardia, an increased PRP, and contractility (peak V(CF)).

Herpes simplex virus gene expression in neurons: viral DNA synthesis is a critical regulatory event in the branch point between the lytic and latent pathways.

Herpes simplex virus establishes a latent infection in peripheral neurons. We examined viral gene expression in rat peripheral neurons in vitro and determined that viral gene expression is attenuated and delayed in these neurons compared with that in Vero cells. In addition, using pharmacologic and genetic blocks to viral DNA synthesis, we found that viral alpha and beta gene expression was upregulated by viral DNA synthesis. Although maximal gene expression in neurons requires viral DNA synthetic activity, activation of viral gene expression was seen even in the presence of herpes simplex virus DNA polymerase inhibitors, but not in the absence of the origin-binding protein. Initiation of viral DNA synthesis is apparently a key regulatory event in the balance between the lytic and latent pathways in peripheral neurons.

The impact of clinical information systems research on the future of advanced practice nursing.

Expert systems are "intelligent" computer programs designed to mimic the decision making of a human expert. This article describes two formal evaluations of one of the first nursing expert systems. Initial results were positive, however, subsequent analysis identified significant limitations in the ability of the expert system to mimic the consultation process of advanced practice nurses (APNs). Because few newly developed systems are being subjected to a clinical trial or to the scrutiny reported here, developing systems may prove to be cost inefficient over time. APNs must be actively involved in the design, development, and evaluation of all nursing expert systems.

A questionnaire to evaluate disability in osteoporotic patients with vertebral compression fractures.

BACKGROUND: Few studies have reported on the functional disability due to vertebral compression factors in osteoporosis. The Osteoporosis Functional Disability Questionnaire (OFDQ) was developed to assess disability in patients with osteoporosis and back pain due to vertebral fractures. The domains of the OFDQ include: quantitative indices of pain, a standard 20-item depression scale, 26 items relating to functional abilities, a scale of social activities, and confidence in the ability of prescribed osteoporosis treatment to reverse disability. METHODS: Reliability of the OFDQ was assessed using test-retest and internal consistency methods. Criterion validity was demonstrated by correlating disability against radiographic evidence of vertebral fractures. Construct validity was demonstrated through comparisons of 81 patients with osteoporosis and fractures to 37 healthy age-matched controls. Additional evidence was found in comparing 45 of the 81 cases who were actively engaged in an exercise program with 36 cases who were sedentary. RESULTS: The test-retest reliabilities ranged from .76 to .93, with internal consistencies from .57 to .96. The OFDQ correlated significantly with relevant spinal pathology, and showed significant improvements in activities of daily living and socialization when active exercisers were compared to inactive patients with osteoporosis. CONCLUSIONS: The OFDQ is a reliable instrument which correlates well with objective measures of osteoporotic spinal damage. It is also sensitive to changes in disability brought about by participation in our aerobic exercise program. The OFDQ may be a useful adjunct to measuring outcomes in other osteoporotic treatment protocols.

Verapamil improves left ventricular filling and exercise performance in hypertensive and normotensive elderly individuals.

OBJECTIVE: To study the effect of verapamil slow release (SR) upon left ventricular diastolic function and exercise capacity in newly diagnosed older hypertensive subjects compared with normotensive elderly and young controls. DESIGN: Cross-sectional prospective trial. INTERVENTIONS: Doppler echocardiography at rest and graded maximal exercise testing (with breath-by-breath gas analysis) before and 4 h after administration of oral verapamil SR 240 mg, and before and after 12 weeks of daily medication. MAIN RESULTS: Verapamil administration normalized resting blood pressure in the older hypertensive group, but did not alter blood pressure in older normotensive or young groups. Resting heart rate was not altered in any of the groups. Both the older hypertensive and normotensive groups showed improvement in measures of diastolic filling after verapamil ingestion. Specifically, the older hypertensive group showed significantly faster isovolumic relaxation time (IVRT). In the older normotensive group IVRT was not changed, but the E:A ratio (the ratio of early to late peak transmitral flow velocity) was increased after verapamil. No differences were observed between the effects of verapamil after acute ingestion (4 h) or with chronic use (12 weeks) in any of the variables measured. In the younger group diastolic filling was not altered after verapamil ingestion. In both the elderly normotensive and hypertensive groups maximum oxygen consumption was significantly improved following verapamil ingestion. Again, no differences were observed between 4 h and 12 weeks. In the younger subjects exercise performance was not changed after verapamil ingestion. CONCLUSIONS: Verapamil SR improved left ventricular diastolic function and exercise performance in hypertensive and normotensive elderly individuals. Verapamil normalized blood pressure in the hypertensive subjects, but did not alter blood pressure in the normotensive elderly or younger subjects.

Infection of sympathetic and sensory neurones with herpes simplex virus does not elicit a shut-off of cellular protein synthesis: implications for viral latency and herpes vectors.

Infection of non-neuronal cell types with herpes simplex virus type 1 (HSV-1) results in the degradation of host mRNA (Kwong & Frenkel 1987) and a shutoff in host protein synthesis (Roizman et al. 1965). This effect is mediated by a virion associated protein that is encoded by the viral vhs gene (Read & Frenkel 1983). This virion host shutoff (VHS) helps regulate viral gene expression and promotes efficient viral replication during the lytic cycle (Kwong & Frenkel 1987). Cultured sympathetic and sensory neurones, in contrast to primary rat fibroblasts, PC-12 cells, and Vero cells, showed no reduction in protein synthesis following infection with HSV-1. The resistance of neurones to VHS may be important in allowing establishment of a latent infection. In addition, this finding has a favourable impact on the idea of using HSV as a vector to deliver foreign genes into neurones.

Sustained effect of and lack of development of tolerance to controlled-release isosorbide-5-mononitrate in chronic stable angina pectoris.

Tolerance has been shown to develop when nitrate preparations are used in such a manner as to produce plasma levels within the therapeutic range continuously over a 24-hour period. However, a period of reduced or low nitrate plasma levels of a few hours per day may limit or completely prevent tolerance development. In 18 patients with chronic stable angina pectoris, a single 60-mg daily dose of a controlled-release preparation of isosorbide-5-mononitrate (ISMN) was compared with the administration of 30 mg, 4 times daily, of immediate-release isosorbide dinitrate (ISDN) in a double-blind, randomized, placebo-controlled, crossover study. The comparisons were carried out on the first day of therapy and after 11 to 14 days of continuous therapy to assess the duration of effectiveness and the development of tolerance. On short-term therapy, both drugs produced a significant improvement in treadmill walking times to moderate angina in comparison with placebo. The values for ISMN were 87 +/- 99 seconds (23%) at 12:30 P.M., 72 +/- 91 seconds (19%) at 5 P.M. and 51 +/- 81 seconds (13%) at 8:30 P.M. For ISDN, the respective values were 71 +/- 83 seconds (19%), 89 +/- 98 seconds (24%) and 79 +/- 87 seconds (21%). There were no significant differences between drugs. Plasma nitrate levels for each drug paralleled the improvements in exercise performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of cardiovascular response to passive tilt in young and elderly men.

To test the hypothesis that altered hemodynamic responses to postural changes are associated with aging, cardiovascular responses to head-up tilt (HUT) and head-down tilt (HDT) were examined in 12 healthy young (average age, 24.6 +/- 1.7 years) and 12 healthy elderly (average age, 68.6 +/- 2.2 years) men. Subjects were passively tilted from supine to 30 degrees, 60 degrees, and 90 degrees HUT and HDT. Responses to these perturbations were determined 5 min after tilting with measures of heart rate (HR), blood pressure (SBP, DBP), and echocardiographically determined left ventricular diameter in systole and diastole (LVIDs, LVIDd). In HUT there were no significant age effects. In both young and elderly, SBP decreased significantly (p less than 0.05), and DBP and HR increased significantly. Ejection fraction (EF), mean arterial blood pressure (MABP), and rate-pressure product (RPP) were unchanged in both groups. In HDT, the hemodynamic responses of the young and elderly were in opposite directions and significant age effects were found for SBP, DBP, HR, LVIDs, EF, MABP, and RPP. In HDT, the young appear to increase cardiac output primarily due to an increase in EF and end-diastolic volume (LVIDd), while HR is unchanged and SBP is decreased. MABP is unchanged, suggesting a small decrease in total peripheral resistance. The elderly may increase cardiac output slightly, owing to an increase in LVIDd with no change in EF, and a large increase in HR. Afterload increased markedly, therefore attenuating any increase in cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)

Dopamine: its potential for inducing ischemic left ventricular dysfunction.

As an agent potentially capable of inducing ischemia in patients with coronary artery disease, dopamine administered intravenously was evaluated as a pharmacologic stress agent by supine radionuclide angiography, and the results were compared with ergometer exercise. In a preliminary group of 11 subjects (4 normal subjects and 7 patients with coronary disease), dopamine alone was administered in increments of 2.5 micrograms/kg per min to a maximum of 15 micrograms/kg per min. There were significant differences between exercise and dopamine in maximal stress heart rates, 129.3 +/- 30.0 versus 88.0 +/- 35.8 beats/min (p less than 0.05) in normal subjects and 118.9 +/- 21.1 versus 87.6 +/- 22.6 beats/min (p less than 0.05) in patients with coronary disease, as well as in maximal stress rate-pressure products, 213.3 +/- 51.4 versus 155.0 +/- 52.5 mm Hg/min X 10(2) (p less than 0.02) in normal subjects and 216.0 +/- 45.6 versus 161.0 +/- 48.6 mm Hg/min X 10(2) (p less than 0.003) in patients with coronary disease. As a result, in these patients the ejection fraction response was significantly different: -3.3 +/- 4.5% with exercise versus + 6.3 +/- 4.6% with dopamine (p less than 0.05). In a second group of 41 subjects (9 normal subjects and 32 patients with coronary disease), atropine (0.6 mg) was administered intravenously before and after every second dopamine dose increment. This produced statistically similar maximal stress heart rates as compared with exercise in all subjects, rate-pressure products in normal subjects and slightly higher values with dopamine in patients with coronary disease: 200.3 +/- 47.2 versus 183.1 +/- 43.0 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

A controlled comparison of tiaprofenic acid and ibuprofen in osteoarthritis.

A multicentre double-blind crossover study of tiaprofenic acid (600 mg daily) against ibuprofen (1.2 g daily) was undertaken in 77 patients with osteoarthritis to compare their efficacy and tolerance. No difference was found between the two agents, both giving pain relief and being safe and acceptable to the majority of patients. It is concluded that in this short-term study, both agents offer effective and safe treatment for osteoarthritis.

Increased prevalence of mitral valve prolapse in patients with migraine.

Patients with classic migraine (69 women and 31 men) selected randomly from a practice list of over 1000 were matched for age, sex and neighbourhood with 100 people who did not have headache problems, and both groups underwent M-mode and two-dimensional echocardiography and clinical examination by cardiologists blinded to the subjects' clinical status. The mean ages were 34.9 +/- 11.3 years for the migraine group and 33.1 +/- 9.9 years for the control group. Definite and possible mitral valve prolapse (MVP), diagnosed according to predefined echocardiographic criteria, were found about twice as often in the migraine group as in the control group (in 15 v. 7 and 16 v. 8 patients respectively); the echocardiograms were definitely normal in 69 migraine patients and 85 controls (chi 2 = 8.39, p less than 0.025). Altogether 25% of the migraine group and 11% of the control group had evidence of MVP from a combination of the echocardiographic and auscultatory findings (chi 2 = 5.72, p less than 0.025). The odds ratio was 2.7, with 95% confidence limits of 1.17 and 6.29. The association between migraine and MVP has implications for the understanding of platelet abnormalities and episodes of cerebral ischemia occurring in both these conditions.

Effects on ventricular function of disopyramide, procainamide and quinidine as determined by radionuclide angiography.

To evaluate the effects of the 3 commonly used antiarrhythmic agents--disopyramide, procainamide and quinidine--on left ventricular (LV) function, these 3 agents were administered in random sequence after control radionuclide angiography performed at rest and during exercise in 17 patients. Drug dosages were tailored to achieve therapeutic blood levels 5 minutes before and 2 to 3 hours after drug administration. The mean dose of disopyramide was 141 +/- 26 mg every 6 hours, procainamide, 441 +/- 100 mg every 4 hours, and quinidine, 401 +/- 101 mg of the gluconate preparation every 6 hours. The patients received the appropriate dosage for 7 or more days before repeat radionuclide angiography was performed. The ejection fraction at rest was: control 60 +/- 13%, disopyramide 55 +/- 11%, procainamide 58 +/- 11%, and quinidine 59 +/- 12%. The exercise ejection fraction was: control 61 +/- 14%, disopyramide 58 +/- 13%, procainamide 58 +/- 12% and quinidine 61 +/- 13%. In neither case, at rest nor during exercise was there any significant difference observed between any of the agents or between any individual agent and control. However, at rest 8 subjects had a 5% or more decrease from the control value with disopyramide, 5 had a 5% or more decrease with procainamide and 6 had a 5% or more decrease with quinidine, whereas during exercise the decreases were 8, 6 and 5%, respectively. These values were not statistically different but suggest that caution should be taken in administering all 3 agents, particularly to patients with impaired LV function, because individual sensitivity to a given agent may precipitate a significant decline in LV function.

The role of Swan-Ganz catheterization in severe pregnancy-induced hypertension.

Swan-Ganz catheterization was performed in 15 postpartum women who presented with severe pregnancy-induced hypertension at a mean gestational age of 31.5 weeks. The mean arterial pressure on presentation was 137.6 torr (range, 116 to 167 torr), and it remained at approximately 115 torr for the next 72 hours. Serial pulmonary capillary wedge pressure, cardiac output, and colloid oncotic pressure were obtained. The mean pulmonary capillary wedge pressure was 9 torr on insertion of the catheter, and it rose to 13 torr by 36 hours. Three patients whose pulmonary capillary wedge pressure was higher than the mean developed pulmonary edema. The mean colloid oncotic pressure was 14.14 torr. We found that hemodynamic monitoring and determinations of colloid oncotic pressure were useful additions to the clinical examination in the postpartum management of patients with severe pregnancy-induced hypertension. Our patients had a broad range of central volume status, cardiac output, and systemic vascular resistance, and the management was tailored accordingly. Although most patients had hyperdynamic pulmonary cardiac function, three developed edema at a lower pulmonary capillary wedge pressure because of decreased colloid oncotic pressure and possibly increased capillary permeability.

Gas transport capacity and echocardiographically determined cardiac size in children.

One hundred and seventeen boys (10, 12, and 14 yr of age) were studied to determine the relation between maximal gas transport capacity (VO2 max) and cardiac size and the interaction of growth and physical activity on this relation. VO2 max was measured during treadmill exercise and heart size was obtained during supine rest by M-mode echocardiography. Left ventricular end-diastolic diameter (LVIDd), resting stroke volume (SV), and calculated left ventricular mass (LVM) were highly correlated (0.75 < r < 0.84) with VO2 max within all age categories. Subjects with high VO2 max had significantly (P < 0.05) larger LVIDd, end-diastolic volumes, resting SV, calculated LVM, and, with the exception of the 12 yr olds, larger left ventricular end-systolic diameters and volumes than subjects with lower VO2 max. Multiple linear regression analysis revealed that fat-free weight accounted for most of the variance in VO2 max and that cardiac dimensions were only of minimal importance in determining maximal gas transport capacity in this study. The seemingly good relationship between cardiac dimensions and VO2 max was mainly attributable to the shared influence of body size on both these factors.

Superior vena cava syndrome: case report. A complication of permanent transvenous endocardial cardiac pacing requiring surgical correction.

Superior vena cava syndrome developed in a patient in whom an endocardial transvenous pacemaker had been inserted five years previously. Venography demonstrated an obstructing lesion at the junction of the superior vena cava and right atrium. Balloon catheter dilatation failed to afford any relief from her progressive symptoms. Exploration of the area revealed a benign fibrotic lesion encircling the pacemaker lead within the right atrium. Excision of the lesion, removal of the lead, and patching the right atrium with pericardium resulted in rapid cure.