Bradycardic responses to vagally mediated bedside maneuvers in healthy volunteers.

PURPOSE: To determine the relative potency in healthy individuals of the vagally mediated reflexes used clinically to inhibit sinoatrial and atrioventricular node function. SUBJECTS AND METHODS: Twenty healthy volunteers with no history of heart disease performed face immersion in cold water and the Valsalva maneuver twice, to maximum endurance and to the subjective point of first discomfort, and face immersion in warm water and the Müller maneuver to maximum endurance only. Right and left carotid massage and left, right, and bilateral eyeball compression were each performed for 15 seconds. Change in heart rate was taken as baseline minus the rate over the slowest three consecutive QRS cycles elicited by each maneuver. Fisher's least-significant-difference multiple comparison procedure was used to analyze heart rate responses. Significance was defined as p less than or equal to 0.05. RESULTS: Maximum pulse decrements from baseline and 95% confidence intervals in beats/minute were as follows: cold-water face immersion to maximum endurance 15.5 (12.3 to 18.5), cold-water face immersion to first discomfort 10.1 (6.7 to 13.1), Valsalva maneuver to maximum endurance 9.2 (6.3 to 12.4), Valsalva maneuver to first discomfort 8.3 (5.0 to 11.3), right carotid massage 7.3 (4.3 to 10.3), left carotid massage 5.2 (2.3 to 8.4), right eyeball compression 6.0 (3.1 to 9.2), left eyeball compression 6.6 (3.6 to 9.5), bilateral eyeball compression 6.0 (3.1 to 9.2), warm-water face immersion 7.0 (3.2 to 9.8), and Müller maneuver 1.6 (-1.3 to 4.9). Bradycardia was significantly greater for cold-water immersion of the face performed to maximum endurance than for all other maneuvers. CONCLUSION: In healthy subjects, the diving reflex is the most potent of the vagally mediated reflexes utilized in clinical practice. Immersion of the face in cold water may prove effective at the bedside when other maneuvers fail to augment vagal tone adequately.

Magnesium bolus or infusion fails to improve expiratory flow in acute asthma exacerbations.

HYPOTHESIS: Intravenous magnesium sulfate improves objective measures of expiratory flow in patients with acute severe exacerbations of asthma. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Urban emergency department. PARTICIPANTS: Forty-eight asthmatic patients aged 18 to 60 years with initial peak expiratory flow rate (PEFR) < 200 L/min who failed to double their initial PEFR after two standardized albuterol treatments. INTERVENTIONS: Subjects were randomized to three groups: a loading dose of magnesium sulfate, 2 g IV over 20 min followed by 2 g/h over 4 h (infusion), magnesium sulfate, 2 g over 20 min followed by placebo infusion (bolus), or placebo loading dose and infusion (placebo). All subjects received standardized aminophylline and steroid therapy. MEASUREMENTS: The PEFR and FEV1 were measured at the start of the loading dose, and 20, 50, 80, 140, 200, and 260 min later using a water-displacement spirometer. Changes from baseline were compared by one-way analysis of variance for repeated measures. RESULTS: Magnesium sulfate administration did not at any time significantly improve either FEV1 (F = 0.036, p = 0.96) or PEFR (F = 0.51, p = 0.61). This study had the power to detect a PEFR difference of 26 L/min and a FEV1 difference of 0.19 L between groups (beta = 0.20, alpha = 0.05 two-tailed significance). CONCLUSION: Use of IV magnesium sulfate in addition to standard therapy does not provide clinically meaningful improvement of objective measures of expiratory flow in patients with moderate to severe asthma exacerbations.

Clinical implications of low QRS complex voltage.

Low QRS voltage on the 12-lead surface ECG is present when the amplitude of all six standard limb leads is less than 5 mm. This finding may be a normal variant, but necessitates investigation of the patient for an underlying cause. A variety of cardiac and systemic diseases may be responsible.

ECG findings in nonpenetrating chest trauma: a review.

Significant ECG findings frequently accompany blunt chest trauma. Surface ECG in conjunction with creatinine phosphokinase (CPK) isoenzyme assay, has been an accepted standard for diagnosis of posttraumatic cardiac dysfunction, or "cardiac contusion." Studies employing recently developed noninvasive cardiac imaging techniques have called this practice into question and have shed new light on the pathophysiology of this clinical entity. As a result, it is appropriate to review the ECG manifestations of blunt chest trauma and to reappraise the utility of the ECG in its evaluation. This article will concern itself solely with nonpenetrating cardiac injuries not requiring initial surgical management, since clinical presentation, course, and prognosis differ when operative therapy is indicated.

Electrocardiographic findings in infective endocarditis.

Management of infective endocarditis includes early recognition of complications and prompt intervention when necessary to avert an untoward result. Among the most serious potential complications of this disorder are those that involve the heart itself. Although the ECG is often normal or nearly so in patients with endocarditis, at other times apparently minor abnormalities may be harbingers of potentially fatal complications. The ECG therefore plays an important role in the initial and ongoing evaluation of patients in whom endocarditis is suspected.

Clinical and cost effectiveness of prophylactic parenteral penicillin in the care of simple wounds undergoing suture repair.

Physicians working in casualty and outpatient departments where adverse conditions prevail often prescribe antibiotic prophylaxis routinely at the time of suture repair of simple wounds. To evaluate this practice, we performed a randomized, controlled study of parenteral chemoprophylaxis of simple wounds undergoing suture repair. Uncomplicated wounds were randomized to either treatment with a combination of benzathine penicillin (2.4 million units) and procaine penicillin (2.0 million units) intramuscularly, or a control group. At the time of suture removal, seven days later, all wounds were reviewed for signs of infection. Of 320 patients enrolled in the study, 173 (54.1%) returned for review. Among treated wounds, 75 of 81 (92.6%) were healing, compared to 79 of 92 (85.9%) controls (p = 0.24). A significantly higher rate of healing was observed when wounds repaired nine or more hours after injury and involving the arms, legs, or trunk were treated (22 of 23, 95.7%) compared to those in whom prophylaxis was omitted (20 of 30, 66.7%) (p = 0.03). Wounds involving the head, and wounds repaired within nine hours after injury had a high rate of healing (greater than 90%), whether prophylaxed or not. Based on a 30% higher healing rate for the patients who benefited from treatment (arm, leg, trunk wounds repaired after nine or more hours), the drug cost of implementing prophylaxis for this group alone was more than five times that of an expectant, non-prophylactic strategy. These results serve to remind practitioners of the possibility that a clinically effective mode of therapy may not necessarily be cost-effective in the delivery of health care.

Emergency medicine in the Third World: two years as director of the Kingston, Jamaica, Public Hospital Casualty Department.

A US emergency physician worked for two years as director of a busy emergency department in a large public hospital in Kingston, Jamaica (West Indies). As expected, medical practice in the Third World required caring for patients with far less than he was accustomed to in the way of diagnostic and therapeutic resources. However, more than one lesson in clinical medicine was provided by local approaches to local problems. Despite resource limitations, innovations and improvements were effected, particularly in wound care. Although working in the Third World can be a rewarding experience, well-meaning health workers from advantaged countries should ensure that their efforts contribute to, rather than detract from, the ability of their hosts to independently provide medical care.

Hypertensive intracerebral hemorrhage stimulating acute myocardial infarction.

We describe the case of a patient who presented with cardiovascular collapse and ECG changes strongly suggestive of acute MI. Our experience and that of others with patients who had sustained intracerebral hemorrhage indicate the potential for this entity to be misdiagnosed as acute MI early in a patient's clinical course. Reports of mistaken administration of thrombolytic therapy to patients with pericarditis or aortic dissection, other conditions that may be electrocardiographically mimic MI, underscore the potential for error. Clinicians should consider the possibility of intracerebral hemorrhage before treatment of MI with thrombolytic agents.

The John Doe syndrome: diagnosis and outcome of patients unidentified at the time of emergency department admission.

Patients unidentified at the time of admission to urban emergency departments are a group about whom little is known. To determine the medical diagnoses and outcomes of these "John" and "Mary Does", we reviewed emergency department charts for these patients admitted from January 1 to December 31, 1988. During this period there were 344 initially unidentifiable patients, for 0.44% of all visits. Age was 36.9 +/- 15.6 years (mean +/- SD); 71% were male. All patients had one or more of the following diagnoses, with mortality highest for cardiopulmonary arrest (n = 42, mortality = 100%), followed by major trauma (163, 68%), drug overdose (27, 41%), miscellaneous medical conditions (11, 18%), neuropsychiatric disorders (59, 12%), acute alcohol intoxication (62, 0%), and seizures (13, 0%). Overall mortality was 47%. Identification was made prior to hospital discharge in 92% of cases. In this group, the most common sources of information were the patient (38%), family (19%), or documents eventually found on the person or in belongings (4%). Survivors were much more likely to be identified than those who died (99% versus 84%, P less than .0001). These observations describe a John Doe syndrome in patients whose identity is obscured by critical illness, the effects of drugs or alcohol, or neuropsychiatric disease. Economic privation is a major underlying risk factor.

Infection control for health care workers caring for critically injured patients: a national survey.

Prevention of transmission of bloodborne pathogens to health care workers (HCWs) involved in resuscitation of critically injured patients presents special challenges. As a step toward creation of a standard, a telephone survey of the infection control practices in this setting of the 100 busiest EDs in the United States (US) was performed. Departmental staff who were knowledgeable about ED infection prevention protocols were questioned about general policy, barrier protection measures, sharps management, and educational programs directed to HCWs. Surveys were completed for 82 EDs. Of these, 56 (68%) either function as primary trauma care facilities for the local community, or are designated level 1 trauma centers by the American College of Surgeons. Specific infection control protocols for trauma resuscitation had been printed and posted by 18 EDs (22%), with the remaining 64 (78%) using the same universal precautions for care of the severely injured as for other patients. A specific policy relating to invasive procedures had been promulgated by 66 EDs (80%). Barrier protection was used by protocol or by custom for care of all critically injured patients by 43 EDs (52%). Impermeable gowns with sleeves were available in 63 EDs (77%). Eye or face protection included face shields by 74 EDs (90%), face masks by 76 EDs (93%), and goggles by 72 EDs (88%). Only 59 EDs (72%) reported that sharp containers were always within arm's reach of HCWs with material to discard. Specially adapted equipment included self-sheathing intravenous catheters (21, 26%) and needle/syringe combinations (16, 20%). Considerable variation exists in infection control practices in busy US EDs during resuscitation of critically injured patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Severe oral phenytoin overdose does not cause cardiovascular morbidity.

STUDY OBJECTIVE: To evaluate the potential for cardiovascular toxicity from severe oral phenytoin overdose. STUDY POPULATION: Fifty-seven patients admitted during a two-year period to an inner-city hospital for severe oral phenytoin overdose, which is defined as a peak level of 40 micrograms/mL or more. METHODS: Case records were reviewed retrospectively for symptoms and signs of phenytoin toxicity, especially circulatory effects. Baseline and toxic 12-lead ECGs, when available, were reviewed in detail. Continuous variables were compared using either paired or unpaired t tests, as appropriate. Significance was taken as P less than or equal to .05. RESULTS: Mean peak phenytoin level was 49.4 +/- 7.7 micrograms/mL. Continuous single-lead ECG monitoring in 36 patients (63%) for a mean of 26.5 +/- 21.6 hours revealed no incidents of dysrhythmia requiring treatment. ECGs recorded during toxicity in 52 cases (91%) revealed no clinically significant abnormalities attributable to phenytoin. ECGs during toxic and baseline states were available for detailed analysis in 15 cases. Ten patients exhibited an increase in PR interval (mean, 19 +/- 10 ms) when toxic, whereas five had a decrease (mean, 18 +/- 11 ms) compared with nontoxic records. No change in heart rate, QRS duration, or corrected QT interval was observed. There were no circulatory complications and no deaths. CONCLUSION: Cardiovascular toxicity is rarely a manifestation of oral phenytoin overdose. Routine management of stable patients with severe phenytoin overdose in a monitored setting is not mandatory.

Evaluation of the 'golden period' for wound repair: 204 cases from a Third World emergency department.

Uncertainty about the existence and duration of a "golden period" for suture repair of simple wounds led us to evaluate prospectively the consequences of delayed primary closure on wound healing. Wounds were eligible for study if they were not grossly infected, and had no associated injuries to nerves, blood vessels, tendons, or bone. Three hundred seventy-two patients underwent suture repair; 204 (54.8%) returned for review seven days later. The mean time from wounding to repair for all patients was 24.2 +/- 18.8 hours. Wounds closed at up to 19 hours after wounding had a significantly higher rate of healing than those closed later: 82 of 89 (92.1%) compared with 89 of 115 (77.4%) (P less than .01). Of 23 wounds sutured 48 or more hours (mean, 65.3) after wounding, 18 (78.3%) were healing at follow-up. In contrast to wounds involving other body areas, the healing of head wounds was virtually independent of time from injury to repair: 42 of 44 (95.5%) wounds involving the head and repaired later than 19 hours after injury were healing, compared with 47 of 71 (66.2%) of all other wounds (P less than .001). On the basis of these data we conclude that there is a 19-hour "golden period" for repair of simple wounds involving body areas other than the head, after which sutured wounds are significantly less likely to heal, and the healing of clean, simple wounds involving the head is unaffected by the interval between injury and repair.

Effect of body locale and addition of epinephrine on the duration of action of a local anesthetic agent.

STUDY OBJECTIVE: Little information exists relating body locale to the duration of action of local anesthetics. We tested the duration of action of a local anesthetic with and without epinephrine at different body locales. PARTICIPANTS: Twenty healthy volunteers aged 27 to 48 years (mean, 32.0 years). INTERVENTIONS: In the first of two experiments (L), 20 subjects had 1 mL buffered 1% lidocaine injected intradermally on the forehead, hand, forearm, and calf. In the second experiment (LE), ten subjects were injected at the same sites with lidocaine containing epinephrine. METHODS: Subjects ranked anesthesia by reaction to pinprick from 0 (complete) to 20 (none) on a scale with testing done every 15 (L) or 30 (LE) minutes and continued until no anesthetic effect was present. Duration of effective and of any anesthesia were times until score of more than 5 and of more than 19, respectively. Mean duration of anesthesia was compared by analysis of variance (between body areas) and paired two-tailed t-test (L vs LE). Significance was taken as P less than or equal to .05. RESULTS: Anesthesia was significantly briefer for the face than for all other body locales by both indexes of duration and for both plain lidocaine and lidocaine with epinephrine (P less than .001 to P less than .05). Anesthesia with epinephrine lasted significantly longer than with lidocaine alone at all body locales and for duration of both effective or any anesthesia (P = .0001 to P = .001). Based on 95% confidence interval limits, the duration of anesthesia at other body locales is predicted to be 1.3- to 3.2-fold that on the face. Confidence interval analysis indicated that addition of epinephrine to lidocaine increases the duration of anesthetic action by 1.3- to 13.0-fold that of lidocaine alone. CONCLUSION: The duration of action of local anesthesia is considerably shorter for the face than for other body areas. Epinephrine significantly increases the duration of action of lidocaine at all body locales.

Controversial issues in clinical management of the simple wound.

The primary goals of the practitioner managing a simple wound are to encourage primary healing and avoid infection. We conclude from this analysis that the four basic aspects of wound management we have reviewed, the timing of wound repair, the preparation of the wound, local anesthetic management, and antimicrobial therapy, will continue to be fertile topics for investigation and debate.

Prospective analysis of mental status progression in ethanol-intoxicated patients.

Distinguishing patients with uncomplicated ethanol intoxication from intoxicated patients with other causes of mental status depression is a common clinical dilemma. The authors serially tested mental status in a group of ethanol-intoxicated patients to determine the interval over which mental status changes could be attributed to uncomplicated intoxication. Study patients were identified by (1) admission breath ethanol greater than or equal to 100 mg/dL; (2) ethanol-related impairment necessitating further observation or treatment; and (3) not critically ill or exhibiting focal neurologic signs. Mental status scores (sums of specific indices of alertness, orientation, and agitation) were determined initially, 1 hour after arrival, then every 2 hours. Causes of mental status depression other than acute intoxication were diagnosed in 16 patients, while another 18 failed to completely normalize mental status by the time of emergency department discharge or hospital admission. The remaining 71 with uncomplicated ethanol intoxication required (mean +/- SD) 3.2 +/- 3.6 hours to normalize mental status scores. A large proportion, however, took considerably longer to normalize mental status: 15 (21%) took 7 or more hours, and three (4%) took as long as 11 hours. Although patients with ethanol-associated depression of mental status lasting 3 hours after emergency department admission should be carefully evaluated for other causes of mental status abnormalities, the authors' observations indicate considerable individual variation in the duration of mental status depression caused by uncomplicated ethanol intoxication.

Clinical and cost-effectiveness of prophylactic penicillin in the care of simple wounds undergoing suture repair - abstract

Many physicians working in Casualty and Outpatient Departments, where adverse conditions prevail, routinely prescribe antibiotic prophylaxis at the time of suture repair of simple wounds. In departments and hospitals with a busy practice in wound care, this custom may make considerable demands on limited pharmacy resources. We therefore performed a randomized, controlled study of parenteral chemoprophylaxis of simple wounds undergoing suture repair. Patients whose wounds spared neurovascular structures, tendon, and bone were randomized to either treatment with a combination of benzathine penicillin (2.4 million units) intramuscularly, or a control group. At the time of suture removal, seven days later, all wounds were reviewed for signs of infection. Of 320 patients enrolled in the study, 173 (54.1 percent) returned for review. Seventy-five of 81 (93 percent) treated wounds were healing, compared to 79 of 91 (86 percent) controls (p>0.2). A significantly higher rate of healing was observed, with prophylaxis, for wounds which were repaired 9 or more hours after injury and involved the arms, legs, or trunk (treated - 22 of 23, 96 percent; p>0,05 prophylaxis omitted - 20 of 30, 67 percent; p<0.05). Wounds involving the head, and wounds repaired within nine hours after injury had a high rate of healing (>90 percent), whether or not prophylaxis was given. Based on a 30 percent higher healing rate for the categories of patient who benefited from treatment (arm, leg, trunk wounds repaired after nine or more hours), it was calculated that the drug cost of implementing prophylaxis for this group alone was more than five times that of an expected, non-prophylactic strategy (J$33.94 vs J$6.55). These results serve to remind practitioners of the possibility that a clinically effective mode of therapy may not necessarily be cost-effective in the delivery of health care (AU)

The effect of late primary repair on healing of simple wounds: analysis of 207 cases - abstract

Although orthodox doctrines of wound care dictate that wounds presenting after a "golden period" of six to 24 hours should be managed with delayed closure, the large number of late presenting wound seen in the Casualty Department, Kingston Public Hospital, makes delayed management problematic. We therefore decided to study, prospectively, the consequences of delayed mangement problematic. We therefore decided to study, prospectively, the consequences of delayed primary closure on wound healing. All wounds seen by the authors between June and September, 1986 were considered eligible for inclusion if (1) they were not grossly infected, (2) there were no associated injuries to structures such as nerves, blood vessels and tendons, and (3) the patients were capable of relating the time of wounding and returning for follow-up. Shortages of sterile equipment necessitated closure of up to eight wounds with each suture set and pair of sterile gloves. Four hundred and sixty-eight patients underwent suture repair; two hundred and seven (44.2 percent) returned for review. The results are summarized as follows: HOURS; - 0-6, 7-12, 13-24, 25-48, >48; (MEAN) - (4.4), (9.3), (20.2), (32.3), (63.8) respectively; SUTURED; - 28, 47, 65, 47, 20 respectively; HEALING; 25, 45 51, 35, 15 respectively; percentHEALING - 89.3, 95.7, 78.5, 74.4, 75.0 respectively. ALL: (22.5), 207, 171, 82.6 respectively. When patients were considered according to whether repair was performed within 22 hours or later, the following was found: HOURS -<22, >22; (M) - (10.3), (35.6) respectively; SUTURED - 107, 100 respectively, HEALING - 98, 73 respectively; percent HEALING - 91.6, 73.0 respectively. The difference in healing between these two groups is significant at the p<0.001 level. We conclude that, although wounds sutured within 22 hours after injury have a significantly greater chance of healing than those repaired later, this advatage is relative, not absolute. The success experienced when suturing was performed more than 48 hours after injury indicates that primary repair is a practical, safe way of managing uncomplicated, late presenting wounds (AU)

Evaluation of the "golden period" for wound repair: 204 cases from a third world emergency department

Uncertainty about the existence and duration of a "golden period" for suture repair of simple wounds led us to evaluate prospectively the consequences of delayed primary closure on wound healing. Wounds were eligible for study if they were not grossly infected, and had no associated injuries to nerves, blood vessels, tendons, or bone. Three hundred seventy-two patients underwent suture repair; 204 (54.8 percent) returned for review seven days later. The mean time from wounding to repair for all patients was 24.2ñ18.8 hours. Wounds closed at up to 19 hours after wounding had a significantly higher rate of healing than those closed later: 82 of 89 (92.1 percent) compared with 89 of 115 (77.4 percent) (P less than .01). Of 23 wounds sutured 48 or more hours (mean, 65.3) after wounding, 18 (78.3 percent) were healing at follow-up. In contrast to wounds involving other body areas, the healing of head wounds was virtually independent of time from injury repair: 42 of 44 (95.5 percent) wounds involving the head and repaired later than 19 hours after injury were healing, compared with 47 of 71 (66.2 percent) of all other wounds (P less than .001). On the basis of these data we conclude that there is a 19-hour "golden period" for repair of simple wounds involving body areas other than the head, after which sutured wounds are significantly less likely to heal, and the healing of clean, simple wounds involving the head is unaffected by the interval between injury and repair. (AU)

Clinical and cost effectiveness of prophylactic parenteral penicillin in the care of simple wounds undergoing suture repair

Physicians working in casualty and outpatient departments where adverse conditions prevail often prescribe antibiotic prophylaxis routinely at the time of suture repair of simple wounds. To evaluate this practice, we performed a randomized, controlled study of parenteral chemoprophylaxis of simple wounds undergoing suture repair. Uncomplicated wounds were randomized to either treatment with a combination of benzathine penicillin (2.4 million units) and procaine penicillin (2.0 million units) intramuscularly, or a control group. At the time of suture removal, seven days later, all wounds were reviewed for signs of infection. Of 320 patients enrolled in the study, 173 (54.1 percent) returned for review. Among treated wounds, 75 of 81 (92.6 percent) were healing, compared to 79 of 92 (85.9 percent) controls (p=0.24). A significantly higher rate of healing was observed when wounds repaired nine or more hours after injury and involving the arms, legs, or trunk were treated (22 of 23, 95.7 percent) compared to those in whom prophylaxis was omitted (20 of 30, 66.7 percent) (p=0.03). Wounds involving the head, and wounds repaired within nine hours after injury had a high rate of healing (>90 percent), whether prophylaxed or not. Based on a 30 percent higher healing rate for the patients who benefitted from treatment (arm, leg, trunk wounds repaired after nine or more hours), the drug cost of implementing prophylaxis for this group alone was more than five times that of an expectant, non-prophylactic strategy. These results serve to remind practitioners of the possibility that a clinically effective mode of therapy may not necessarily be cost-effective in the delivery of health care.(AU)