Potential exposure to Australian bat lyssavirus is unlikely to prevent future bat handling among adults in South East Queensland

Despite ongoing public health messages about the risks associated with bat contact, the number of potential exposures to Australian bat lyssavirus (ABLV) due to intentional handling by members of the general public in Queensland has remained high. We sought to better understand the reasons for intentional handling among these members of the public who reported their potential exposure to inform future public health messages. We interviewed adults who resided in a defined geographic area in South East Queensland and notified potential exposure to ABLV due to intentional handling of bats by telephone between 1 January 2012 and 31 December 2013. The participation rate was 54%. Adults who reported they had intentionally handled bats in South East Queensland indicated high levels of knowledge and perception of a moderately high risk associated with bats with overall low intentions to handle bats in the future. However, substantial proportions of people would attempt to handle bats again in some circumstances, particularly to protect their children or pets. Fifty-two percent indicated that they would handle a bat if a child was about to pick up or touch a live bat, and 49% would intervene if a pet was interacting with a bat. Future public health communications should recognize the situations in which even people with highrisk perceptions of bats will attempt to handle them. Public health messages currently focus on avoidance of bats in all circumstances and recommend calling in a trained vaccinated handler, but messaging directed at adults for circumstances where children or pets may be potentially exposed should provide safe immediate management options.

Audit of Postal Test Kits in Edinburgh for Chlamydia trachomatis as an alternative to genitourinary medicine clinic attendance

Our objective was to investigate whether Postal Test Kits (PTKs) for Chlamydia trachomatis in Edinburgh offer an alternative to genitourinary (GU) medicine clinic attendance. All PTKs returned in the Edinburgh area over a six-month period from August 2005 were audited. Data on age and previous access to GU medicine services were collected. Return rates of kits from various sources were calculated. In all, 799 kits were returned with 72 (9%) chlamydia prevalence, and 10% had previously attended a GU medicine clinic. The largest proportion of kits were used by the 16-29 years old age group. Return rates of kits varied with distribution point, with only 15% returned from GU medicine. PTKs appear to be targeting an appropriate high-risk age group and a population not otherwise accessing GU medicine clinics. However, return rates are low and kits do not offer an adequate alternative to GU medicine clinics.

Apparent Mendelian inheritance of breast and colorectal cancer: chance, genetic heterogeneity or a new gene?

It is not uncommon for cancer geneticists to be referred families with apparently Mendelian co-inheritance of breast and bowel cancer. Such families present a particular problem as regards the intensity of their screening for these diseases and the utility of genetic testing. Many 'breast-colon' cancer families probably result from chance clustering of two common cancers. Other 'breast-colon' cancer families may result from known cancer syndromes, such as hereditary breast-ovarian cancer or hereditary non-polyposis colon cancer, either by conferring a high risk of one cancer type and a slightly increased risk of the other, or through a predisposition to one of the two cancers and chance occurrence of the other. Anecdotally, however, many geneticists wonder about the existence of a distinct 'breast-colon cancer syndrome', since some families present good a priori evidence of genetic disease and yet cannot readily be accounted for by known genes or chance. The identification of unknown 'breast-colon cancer' genes is likely to be difficult, relying primarily on candidate gene analysis, including loci separately implicated in breast or colorectal cancer, or in other multiple cancer syndromes. Studies such as those on APC I1307K and CHEK2 1100delC may suggest the way forward for the identification of 'breast-colon cancer' genes.

Isolated neurosarcoidosis--a diagnostic enigma: case report and discussion

Neurosarcoidosis is a rare, but well-recognized cause of hypopituitarism with a predilection for the hypothalamus. We describe a case of panhypopituitarism in a 57-yr-old Asian lady, associated with an infiltrating hypothalamo-hypophyseal lesion, and other intracranial deposits, initially diagnosed as cerebral tuberculomata. Despite antituberculous therapy, the intracranial lesions progressed with significant clinical deterioration. Repeated lumbar puncture, magnetic resonance imaging scans, liver biopsy and Gallium scan were noncontributory, and the diagnosis of isolated neurosarcoidosis was established only following biopsy of an intracranial lesion. The lesion regressed on steroid and azathioprine therapy. Isolated neurosarcoidosis poses a considerable management problem. We review recent advances in the investigation, diagnosis, and treatment of this condition.

Using test dose challenges to restore essential therapy in patients with idiopathic anaphylaxis and pharmacophobia: report of a patient with idiopathic anaphylaxis and statin phobia

Idiopathic anaphylaxis (IA) is a well-documented condition in which anaphylaxis occurs in the absence of an identifiable precipitant. However, many patients with IA find it difficult to accept this diagnosis and continue to search for an external cause. It is not uncommon for these highly anxious patients to discontinue essential medications that they feel are responsible for the reaction despite reassurance from their physicians to the contrary. In extreme cases, these patients may develop an actual phobia to preexisting medications and avoid them despite adverse consequences to their health. To illustrate this concept, we report a case involving a female patient with familial hypercholesterolemia who experienced a single episode of IA and developed a "statin phobia," falsely implicating her medication (lovastatin) for the reaction. After 5 years of failed therapy with other antihyperlipidemic agents, the patient finally agreed to undergo test dosing to a similar statin agent atorvastatin. On successful completion of the test, she resumed therapy with atorvastatin and her low-density lipoprotein (LDL) levels were reduced by 50% over 5 months. We conclude that patients with a confirmed diagnosis of IA who manifest phobic responses to beneficial medications should be reassured of the diagnosis promptly by their physician. When reassurance fails and the medication is essential to the patient's health, test dose challenges may be conducted to reintroduce the drug to the patient's regimen.

Three nursing home outbreaks of Norwalk-like virus in Brisbane in 1999

We report on three nursing home outbreaks of gastroenteritis in Brisbane in 1999. The presence of Norwalk-like virus (NLV) genogroup 2 was demonstrated by reverse transcription polymerase chain reaction (RT-PCR) in all three outbreaks. Common findings of these investigations were rapid spread of the illness within the institutions and difficulties in identifying a common source. Nursing home populations are vulnerable and it is important for each institution to have infection control policies in place so outbreaks can be managed promptly. This includes the exclusion of ill staff for 48 to 72 hours after recovery from illness. Genogrouping of NLV by RT-PCR can take several days so control measures will generally have to be instituted before results become available.

The use of Doppler and atrioventricular plane motion echocardiography for the detection of changes in left ventricular function after training

In this study we compared the efficacy of Doppler and atrioventricular plane motion echocardiography in detecting the changes in left ventricular function caused by moderate-intensity training. Fifty-nine healthy men and women (aged 40-68 years) were divided into either a group of walkers (n = 32) or controls (n = 27). Pre-intervention, there were no significant differences between the groups for gender, age, height, mass or predicted maximal oxygen consumption. The walkers completed a progressive 18-week walking programme that resulted in an estimated mean gross energy expenditure whilst walking of 4.0 (1.3) MJ x week(-1) for the duration of the study, and 5.9 (1.7) MJ x week(-1) during the final 6 weeks. After the 18-week programme there were no significant changes in Doppler measures of early or late filling velocities. However, the walkers showed an increase in the velocity of relaxation (1.2 cm x s(-1)) (P < 0.02) of the left free wall, as measured using atrioventricular plane motion echocardiography, while the controls showed no significant changes. The findings suggest that atrioventricular plane motion echocardiography is more sensitive than Doppler echocardiography in detecting the left ventricular changes caused by exercise intervention.

Drug eruptions and isotypic antibody responses to streptokinase after infusions of anisoylated plasminogen-streptokinase complex (APSAC, anistreplase)

BACKGROUND

Anisoylated plasminogen-streptokinase complex (APSAC, anistreplase) is a thrombolytic agent (131 kd) used for treatment of myocardial infarction. Like its principal antigenic determinant, streptokinase, APSAC has been reported to cause a variety of allergic reactions.

OBJECTIVE

This study was intended to determine any association between isotypic antibody responses to streptokinase and observed allergic reactions to APSAC.

METHODS

We measured sequential IgM, IgG, IgA, and IgE antistreptokinase serum levels in 21 patients who received APSAC or tissue-type plasminogen activator in a prospective, double-blind study.

RESULTS

Of 11 patients who received APSAC, four had maculopapular rashes and one had urticaria; those with maculopapular rashes had significantly higher rises in serum IgM, IgG, IgA, and IgE antistreptokinase levels. We could not, however, define a temporal relationship between rises in antistreptokinase levels of a particular isotype and the onset of maculopapular rashes. The patient who had urticaria had no antistreptokinase responses but had also received several other potentially causal drugs. None of 10 patients who received tissue-type plasminogen activator had allergic reactions or significant rises in serum antistreptokinase levels.

CONCLUSION

The more vigorous panisotypic antistreptokinase responses observed in patients who received APSAC and had maculopapular rashes may reflect generalized immune system activation that included other immune responses (such as cell-mediated hypersensitivity) that were responsible for these reactions.

Predictors of early morbidity and mortality after thrombolytic therapy of acute myocardial infarction. Analyses of patient subgroups in the Thrombolysis in Myocardial Infarction (TIMI) trial, phase II

BACKGROUND

Thrombolysis has altered treatment of acute myocardial infarction (AMI). Therefore, reevaluation of predictors of outcome and treatment strategies is appropriate.

METHODS AND RESULTS

Clinical variables collected prospectively for the 3,339 patients of the Thrombolysis in Myocardial Infarction II study were analyzed retrospectively to identify predictors of clinical events at 42 days and earlier and to identify subgroups in which an invasive or conservative strategy might be superior. Pulmonary edema/cardiogenic shock presented as the strongest independent correlate with death (relative risk, 6.0). In two subgroups, mortality differed between the invasive and conservative strategies: 1) Patients with versus without prior AMI had a higher mortality in the conservative strategy (11.5% versus 3.5%, p less than 0.001); in the invasive strategy, the mortality rates were similar (6.0% and 5.1%). 2) Patients with diabetes mellitus and no prior AMI had a higher mortality in the invasive than in the conservative strategy (14.8% versus 4.2%, p less than 0.001). Reinfarction was not independently correlated with baseline characteristics except with history of angina (relative risk, 1.9). Mortality was lower in current smokers and ex-smokers versus never-smokers (3.6% and 4.8% versus 8.0%, p less than 0.001). Current smokers had a lower risk profile (p less than 0.001), including age, pulmonary edema/cardiogenic shock, history of hypertension, and diabetes. The rate of reinfarction was lower in current smokers versus ex-smokers and never-smokers (4.6% versus 8.3% and 8.8%, p less than 0.001). "Not current smoker" was an independent correlate with reinfarction (relative risk, 1.9). The coronary anatomy did not differ among the current smokers, ex-smokers, and never-smokers.

CONCLUSIONS

The strong independent correlation of pulmonary edema/cardiogenic shock with death suggests that thrombolysis is not sufficient to improve survival in these patients. The higher mortality in patients with versus without prior AMI in the conservative strategy suggests that early catheterization and revascularization of these patients might be beneficial. Conversely, the higher mortality in diabetes without prior AMI in the invasive than in the conservative strategy suggests that early aggressive management might not be suitable in this subgroup except for clinical indications. Reinfarction was not predictable by clinical variables except by history of angina. The finding that "not current smoker" was an independent correlate with reinfarction was unexpected.

The effect of clonidine on the cessation of cigarette smoking

The effect of clonidine on smoking cessation was studied by randomly assigning 186 smokers in a double-blind fashion to either placebo or clonidine. Abstinence from smoking was reported more frequently by subjects receiving clonidine, but the difference was statistically significant only at the end of the first week (34.4% vs 21.5%; p less than 0.05). Bothersome side effects were common and resulted in the early discontinuation of the study medication by 23 of the subjects taking clonidine and eight taking placebo (p less than 0.05). Although this study did not demonstrate a significant effect of clonidine on smoking cessation, a beneficial trend was detected and therefore further trials with transcutaneous delivery of this agent in combination with behavior modification techniques are warranted.

The use of epinephrine in the treatment of older adult asthmatics

Three subcutaneous doses of 0.3 mL 1:1,000 epinephrine were given 20 minutes apart to 95 adult asthmatics 15 to 96 years old during 108 asthma exacerbations. Patients with a history of recent myocardial infarction or of angina were excluded from our study. Heart rhythm and rate, blood pressure, respiratory rate, and clinical response were prospectively evaluated before, during, and after the administration of epinephrine. There was no significant difference in the occurrence of ventricular arrhythmias between patients less than 40 and more than 40 years old. The mean systolic and diastolic blood pressures, mean heart rate, and mean respiratory rate decreased with treatment in the older population. Our results suggest that epinephrine is safe to use in acute asthmatics of any age.

Adverse reactions to thrombolytic agents. Implications for coronary reperfusion following myocardial infarction

The use of thrombolytic agents to dissolve coronary artery thrombi causing acute transmural myocardial infarctions has been shown to decrease short term mortality, and improve left ventricular function, in patients with acute transmural myocardial infarction. Several thrombolytic agents are currently available which differ mainly in cost, antigenicity, and mechanism of action. Current investigations are being directed at finding safer, more effective thrombolytic agents and at developing optimal therapy following thrombolysis. The complications of thrombolytic therapy are for the most part minor and reversible. Immediate and delayed hypersensitivity to streptokinase is rare. Hypotension and arrhythmias commonly accompany myocardial reperfusion and are usually benign and self-limited. Haemorrhagic complications are the most frequent and serious problems following the use of thrombolytic agents. They can be lessened by the proper selection of patients to avoid those at high risk of bleeding. The avoidance of unnecessary arterial and venous punctures will decrease the incidence of minor but annoying local bleeding. Those agents which are activated at the site of thrombi will hopefully cause fewer bleeding episodes, but early experience with these agents has not been able to demonstrate a lower rate. With careful attention to patient selection and follow-up, thrombolytic agents can be safely and effectively used in the management of patients with acute myocardial infarction.

Role of heparin after intravenous thrombolytic therapy for acute myocardial infarction

The optimal approach to management of patients after thrombolytic therapy for acute myocardial infarction (AMI) is unclear. The role of anticoagulation with heparin was evaluated in 75 consecutive patients who received intravenous streptokinase for AMI. Heparin therapy was titrated to keep the partial thromboplastin time (PTT) between 90 and 120 seconds. Seventeen episodes of definite myocardial ischemia (associated with reversible electrocardiographic changes) were observed in 13 patients. When episodes of probable myocardial ischemia are included (typical chest pain relieved by nitroglycerin or associated with more than a 15-mm Hg change in blood pressure but without electrocardiographic changes), 52 episodes occurred in 28 patients. Four episodes of definite and 4 of probable myocardial ischemia occurred within 24 hours of discontinuation of heparin. Analysis of the level of anticoagulation as assessed by PTT at the time of the ischemic events shows that ischemia occurred more often at lower PTTs. Nine hemorrhagic complications occurred, all within 24 hours of streptokinase infusion. In 4 patients bleeding was believed to be major and heparin administration was discontinued; 2 patients with gastrointestinal bleeding required blood transfusions. Our data suggest that after thrombolytic therapy for AMI, the level of anticoagulation is inversely related to the frequency of recurrent ischemic events; that discontinuation of heparin is frequently associated with ischemia; and that administration of heparin is associated with a low incidence of hemorrhagic complications.

Abnormal thallium 201 scintigraphy during low-dose vasopressin infusions

Thallium 201 (201Tl) myocardial scans were obtained in 16 patients just prior to the discontinuation of a vasopressin infusion (.1 to .2 units/min) administered for the treatment of upper gastrointestinal bleeding. Repeat scintigraphy was performed two to three hours after the vasopressin was stopped. Eleven of the 16 patients (69 percent) demonstrated areas of decreased myocardial 201Tl uptake that resolved after the infusion was stopped. Heart rate-blood pressure product was significantly lower at the time of the second scan. Autopsies were secured in three of 11 scan-positive patients: one had severe coronary artery obstruction, one nonsignificant disease, and another had normal coronary arteries. Vasopressin, even at low doses, can induce abnormalities in myocardial perfusion that are probably mediated by a direct effect on the coronary circulation. They are usually not detectable by routine monitoring techniques and conceivably form the basis for the cardiovascular morbidity associated with the use of this agent.

Identification of patients at risk for anaphylaxis due to streptokinase

To identify patients at risk for immediate-type allergic reactions to streptokinase, we performed streptokinase skin tests on patients immediately before planned administration of intravenous streptokinase for treatment of acute myocardial infarction. Forty-five patients had negative skin tests and received streptokinase without allergic reaction. One patient had a positive skin test and was given urokinase instead, without incident. Positive skin tests were also present in a patient who had recently had an anaphylactic reaction to streptokinase, and in two physician volunteers who had been sensitized to streptokinase during initial determination of the optimal skin testing dose. Immunoassays for IgE to streptokinase were performed on serum samples from skin-tested patients and volunteers, and on 16 other patients who had not been skin tested but had previously received streptokinase without allergic reactions. The skin test was a sensitive and specific indicator of elevated levels of IgE to streptokinase. We propose that skin testing immediately before streptokinase administration is a practical approach for identifying patients at risk for immediate-type allergic reactions to streptokinase, and its use may possibly prevent anaphylaxis and death.

Release of unassembled rat cardiac myosin light chain 1 following the calcium paradox

To determine the intracellular source and release kinetics of myosin light chain 1 immediately following irreversible myocytic injury, we perfused rat hearts in a Langendorff apparatus under control conditions (20 minutes), or during global cellular injury produced by oxygenated, calcium-free perfusion (5 minutes), followed by reperfusion with buffer containing 2.5 mM calcium (15 minutes). Light chain 1 concentration (double antibody radioimmunoassay) and creatine kinase activity were measured in both the coronary effluent and the 140,000 g supernatant extract of perfused ventricular tissue (after homogenization and ultracentrifugation). Calcium reperfusion caused the rapid release of both light chain 1 and creatine kinase activity (peak light chain 1 = 1.09 +/- 0.19 micrograms/g; peak creatine kinase = 74.9 +/- 10.7 IU/ g at 1 minute, mean +/- SD, n = 3); 28.5 +/- 13.5% of total light chain 1 and 86.5 +/- 0.6% of total creatine kinase activity were depleted from the tissue extract during the 15-minute reperfusion. No light chain 1 or creatine kinase was detected in the effluents of control-perfused hearts. Dodecyl sulfate polyacrylamide gel electrophoresis and immunodetection with specific antibody to myosin heavy chain and light chain 1 showed that the effluent light chain 1 was of similar molecular weight (mol wt = 27,000) to the subunit bound to myofibrils. In addition, light chain 1 was released in the absence of myosin heavy chain. Thus, a small soluble pool of unassembled myosin light chain 1 subunits exists in the cytoplasm of cardiac myocytes that is released from irreversibly injured cells. This pool demonstrates initial washout kinetics similar to creatine kinase.

Myocardial necrosis in a patient with mixed connective tissue disease

A 23-year-old black woman with mixed connective tissue disease developed acute onset of shortness of breath and evidence of pulmonary edema. Cardiac isoenzymes, electrocardiograms and radionuclide myocardial scintigraphy were consistent with focal myocardial necrosis. The patient has had no further myocardial complication since initiation of therapy with steroids.

Prophylaxis of supraventricular tachyarrhythmia after coronary bypass surgery with oral verapamil: a randomized, double-blind trial

This study investigated the efficacy of oral administration of verapamil, started 24 hours after coronary artery bypass grafting (CABG), in reducing the incidence of postoperative supraventricular tachyarrhythmia (SVT). Two hundred patients were randomly assigned in a double-blind fashion to receive a one-week course of either a placebo or 80 mg of verapamil every 6 hours. Overall, SVT developed in 23 control and 14 verapamil-treated patients, a 39% reduction in incidence (p less than 0.10). Of the patients who received at least four doses and continued to receive the study drug, 17 in the control and 7 in the verapamil group experienced SVT, a 53% decrease in incidence (p less than 0.06). Atrial fibrillation constituted 34 of the 37 SVT episodes and was associated with a slower ventricular response in the group given verapamil (115 +/- 8 versus 156 +/- 4 beats per minute; p less than 0.001). No evidence was found linking postoperative SVT with the withdrawal of beta-blocking drugs. Adverse effects required that 20 patients in the verapamil and 6 in the placebo group be removed from the study. Hypotension or pulmonary edema or both developed in 13 of the patients receiving verapamil, but in only 1 of the control patients (p less than 0.001). We conclude that although verapamil has potential merit for the prophylaxis of SVT after CABG, its use in this setting is associated with a high incidence of unacceptable hemodynamic side effects.

Frequency of pericardial effusion as determined by M-mode echocardiography in acute myocardial infarction

A pericardial friction rub occurs in 6 to 16% of patients after acute myocardial infarction (AMI), but the incidence of pericardial effusion (PE) is not known. M-mode echocardiography was done 1, 3 and 5 days after AMI in 43 consecutive patients admitted within 24 hours of AMI, and PE was detected in 16 (37%). The PE was small in 7 patients, moderate in 6 and large in 3. A pericardial friction rub developed in 8 (19%), of whom only 4 had PE. Pleuritic chest pain diminished by sitting up and relieved by antiinflammatory agents developed in 12 (28%), of whom only 5 had PE. The peak creatine kinase level was significantly higher in patients with PE (1,769 +/- 1,003 U) than in those without (1,181 +/- 838 units). More patients with PE were in Killip classification II, III or IV (11 of 16 [69%] vs 9 of 27 [33%]). The presence of PE was not associated with age, site of AMI, development of Q waves, use of heparin or previous AMI. In conclusion, PE as detected by M-mode echocardiography is frequently present after AMI, and its presence is not closely associated with the occurrence of a pericardial friction rub or typical pericardial pain.

Association of methemoglobinemia and intravenous nitroglycerin administration

Significant elevation of arterial methemoglobin levels has been reported with the administration of intravenous (i.v.) nitroglycerin (NTG). To determine the incidence and clinical significance of this side effect of i.v. NTG, serial arterial methemoglobin levels were determined in 50 consecutive patients receiving i.v. NTG for 48 hours or longer. The mean i.v. NTG infusion rate was 290 +/- 13 micrograms/min (4.1 +/- 0.2 micrograms/kg/min) and the mean duration of infusion was 7.1 +/- 0.5 days. The mean methemoglobin level for the 141 samples was 1.57 +/- 0.08%, which differs from the control mean value in our laboratory of 0.44 +/- 0.01%. Although no patient had clinical symptoms from methemoglobin, 20 patients had elevated (greater than 1%) levels on at least 1 measurement. Seventy-eight of the 141 samples analyzed were in the normal range; 63 determinations were between 2 and 5%. Patients with normal methemoglobin levels differed from those with abnormal levels in the dose of i.v. NTG (mean infusion rate 244 +/- 16 vs 351 +/- 17 micrograms/min; total cumulative dose 1,612 +/- 153 vs 3,398 +/- 308 mg). Age, weight, renal and hepatic function, and arterial oxygen saturation were not different between the groups. In conclusion, clinically significant methemoglobinemia is uncommon with i.v. NTG infusion; however, when large doses of NTG are administered, this complication is more likely.

Intravenous nitroglycerin for the treatment of angina at rest unresponsive to standard nitrate therapy

Thirty-five patients who had angina at rest that was unresponsive to standard therapy comprised of oral or topical nitrates and beta-blocking drugs were treated with a continuous infusion of intravenous nitroglycerin (IVNTG). The infusion was started at 10 micrograms/min and increased by 10 micrograms/min increments every 5 minutes until an infusion rate of 50 micrograms/min was reached. After each episode of rest angina, the infusion was increased by 50 micrograms/min in the same stepwise manner. Data from a 24-hour baseline control period were compared with those from a 24-hour IVNTG endpoint period at which time the highest IVNTG infusion rate was administered. The average IVNTG infusion rate was 140 +/- 15 micrograms/min. With IVNTG therapy, the number of episodes of angina at rest decreased from 3.5 +/- 0.4 to 0.3 +/- 0.1, sublingual nitroglycerin use decreased from 1.9 +/- 0.3 to 0.4 +/- 0.1 mg/day, and morphine sulfate administration decreased from 5.5 +/- 1.3 to 0.4 +/- 0.2 mg/day (all p less than 0.001). When each patient's response on the endpoint day was analyzed, 25 were defined as complete (no rest angina), 8 as partial (greater than 50% decrease in the number of episodes/day from control values), and 2 as nonresponders. No significant drug-induced adverse effects occurred. IVNTG appears to be effective therapy for angina at rest refractory to standard oral and topical medications.

Excessive serum lidocaine levels during maintenance infusions: mechanisms and prevention

Clinical and pharmacokinetic data were reviewed in 72 patients who developed excessive lidocaine serum levels during maintenance infusions. Fifty-one of the 72 (70%) were cardiac patients who had mean lidocaine excretory clearances less than one half of normal. Forty percent of these became toxic in spite of a reduced infusion rate (30 micrograms/kg/min). Seven patients with normal excretory mechanisms became toxic when they received large doses of lidocaine. The remaining 14 cases lacked an identifiable cause to explain the development of higher than therapeutic serum levels. Inordinately high serum levels of monoethylglycinexylidide (MEGX), an active lidocaine metabolite, were found in seven patients, but in only one was MEGX greater than lidocaine. Prolonged infusions (24 hours or greater) were not clearly associated with the worst lidocaine elimination clearances. Lidocaine toxicity was life-threatening or significantly complicated the management of 15 patients. Based on the data presented, guidelines are offered as an approach to the prevention of toxicity from maintenance lidocaine infusions.

Intracardiac injections during cardiopulmonary resuscitation. A low-risk procedure

Fifty-three patients were observed prospectively for the development of complications resulting from 147 intracardiac injections (ICIs) received during cardiopulmonary resuscitation (CPR). Although pericardial effusion was noted in six of 17 echocardiograms and a hemopericardium found in eight of 28 autopsies, cardiac tamponade was not observed. A pneumothorax developed in one patient. None of the autopsies disclosed coronary artery or ventricular lacerations. Percutaneous puncture of the heart during CPR seldom results in serious complications. When other sites are not readily available, ICIs are safe and valid for the administration of emergency medication.

Technetium-99m stannous pyrophosphate myocardial scintigraphy after cardiopulmonary resuscitation with cardioversion

Thirty consecutive patients underwent technetium-99m stannous pyrophosphate myocardial scintigraphy 48--72 hours after successful cardiopulmonary resuscitation and direct current cardioversion. Five patients with transmural myocardial infarctions by ECG and enzyme determinations were correctly identified by scintigraphy. Myocardial scans were positive in five of nine patients with nontransmural infarction. Of 16 patients without evidence of myocardial infarction, only two (13%) had false-positive myocardial scans. The overall accuracy of imaging in this series was 80%. We conclude that false-positive scans after cardiopulmonary resuscitation with electrical cardioversion are infrequent, and do not significantly detract from the value of myocardial scintigraphy in the diagnosis of myocardial infarction.

The validity of determinations of pulmonary wedge pressure during mechanical ventilation

Changes in the mean pulmonary wedge pressure were measured during temporary disconnection from a ventilator in 29 patients to assess the effects of therapy with controlled-volume ventilation on determinations of pulmonary wedge pressure. In 16 observations performed during therapy with intermittent positive-pressure ventilation, the mean value for the pulmonary wedge pressure was the same (10.3 mm Hg) with the patients connected to or disconnected from the ventilator. Thirteen of the patients were also maintained on therapy with positive end-expiratory pressure (PEEP); the mean (+/- SD) of 17 measurements of pulmonary wedge pressure did not show a significant variation on cessation of mechanical ventilation (12.5 +/- 6.7 mm Hg vs 11.7 +/- 6.9 mm Hg; P greater than 0.05). We conclude that pulmonary wedge pressure can be measured accurately at the end of exhalation during the administration of positive-pressure ventilation with 10 cm H2O of PEEP. The suggested practice of discontinuing mechanical ventilation in order to obtain a more exact measurement is not warranted.

The weights of aboriginal infants: a comparison over 20 years

At Cherbourg Aboriginal Settlement the weight gains of infants remained at a constant level below the Australian average from 1953 to 1972. During this period the infant death rate decreased from about 28 per 1,000 live births to about 40 per 1,000 live births. At Palm Island Settlement the death rates have remained high and the growth rates low. The pattern at Cherbourg suggests that the people at Cherbourg have learnt how to use appropriately the hospital and health services, but have not yet made any major changes in the standards of infant care.

Reassessment of the assumed A-V oxygen content difference in the shunt calculation

A study was undertaken in 15 patients to compare measured and assumed arteriovenous oxygen (A-V O2) content differences and their effects on resultant shunt calculations. All patients were on volume ventilators and demonstrated a stable cardiovascular state. Simultaneous measurements of the O2 content of a pulmonary artery (PA) and of a superior vena cava (SVC) sample were compared. A mean A-V 02 content difference of 3.5 plus or minus 0.8 volumes percent was obtained from the PA and 2.6 plus or minus 1.1 volumes percent from the SVC. The resultant shunt calculations derived from measured A-V 02 content differences were compared with the calculation based on an assumed A-V O2 content difference of 5 volumes percent. A method for extrapolating a "true" A-V 02 content difference from an SVC blood sample was obtained. The extrapolated value resulted in a more representative "true shunt" calculation in 13 of the 15 patients.