Comparison study of intraosseous, central intravenous, and peripheral intravenous infusions of emergency drugs

Intraosseous infusion of emergency drugs is a lifesaving alternative to intravenous administration when intravenous access cannot be rapidly established. We studied the comparative pharmacokinetics of the following six emergency drugs and solutions: epinephrine hydrochloride, 0.01 mg/kg; sodium bicarbonate, 1 mEq/kg; calcium chloride, 10 mg/kg; hydroxyethyl starch, 10 mL/kg; 50% dextrose in water, 250 mg/kg; and lidocaine hydrochloride, 1 mg/kg. Studies were conducted in normotensive, anesthetized dogs, with three animals studied with each of the drugs or solutions and each animal being treated with all three routes of administration (central intravenous, peripheral intravenous, and intraosseous) in randomized sequence. The effects of epinephrine were also assessed in a shock model. The intraosseous route of administration was comparable with the central and peripheral intravenous routes for all of the emergency drugs and solutions studied, with equivalent magnitudes of peak effect or drug level and equal or longer durations of action. Time to placement of the intraosseous needle varied from 15 seconds to 5 minutes, with a mean of 60 seconds. Time to placement of the needle varies with the skill and experience of the individual. With experience, all individuals could place the intraosseous needle in 60 seconds or less. The intraosseous route is comparable in effect to the central and peripheral intravenous routes of drug administration for epinephrine, sodium bicarbonate, hydroxyethyl starch, calcium chloride, 50% dextrose in water, and lidocaine and is a clinically feasible alternative when intravenous access will be critically delayed.

The bone marrow as a source of laboratory studies

The intraosseous route is an emergency alternative to the IV route for the administration of drugs and fluids. Another emergency function of intravascular access is obtaining blood samples for blood gases, laboratory studies, and blood cultures. One of the drawbacks to using the intraosseous route as an alternative to IV access has been the persistent need to establish IV access to obtain blood samples. We obtained bone marrow samples from ten healthy anesthetized dogs and analyzed the usefulness of the samples in providing meaningful laboratory studies when compared with simultaneous arterial and venous samples for blood electrolytes, blood chemistries, blood gases, and hemoglobin. There was no significant difference (P greater than .10) in blood electrolytes (sodium, potassium, chloride, and carbon dioxide) drawn from the intraosseous, arterial, and venous sites. The blood chemistries (blood urea nitrogen, creatinine, total protein, albumin, calcium, phosphorous, uric acid, total bilirubin, and SGOT) also were not significantly different (P greater than .10). Significant differences were obtained for glucose comparing intraosseous with arterial (P = .03), whereas intraosseous versus venous was only marginally significant (P = .06). Significant differences were also obtained for alkaline phosphatase when comparing intraosseous with arterial (P = .03), whereas comparison with venous was only marginally significant (P = .06): lactate dehydrogenase differences were marginally significant when comparing intraosseous with arterial (P = .09) and venous (P = .06) blood. Hemoglobin values were not significantly different when comparing results for the three sites (P greater than .25).(ABSTRACT TRUNCATED AT 250 WORDS)

The hemodynamic and cardiovascular effects of near-drowning in hypotonic, isotonic, or hypertonic solutions

It has been postulated that near-drowning in fresh water may cause hemodilution and hypervolemia due to the hypotonicity of the aspirated water. In contrast, near-drowning in seawater, because of its hypertonicity, may lead to hypovolemic shock. We evaluated the hemodynamic effects of the instillation of 20 mL/kg of solutions of various tonicities (sterile water, 0.225% sodium chloride, 0.45% sodium chloride, normal saline, 2% sodium chloride, and 3% sodium chloride) into the lungs of anesthetized dogs and compared the results with those for control animals who were made anoxic for five minutes. There was no difference in the hemodynamic effects of hypotonic, isotonic, or hypertonic solutions when compared with anoxic controls. There was an immediate fall in cardiac output and increase in pulmonary capillary wedge pressure, central venous pressure, and pulmonary vascular resistance, regardless of the solution, which was statistically the same as the changes in the anoxic controls (P greater than .02). Likewise, the effective dynamic compliance of the lungs decreased precipitously, was indistinguishable between solutions, and was not statistically different from the anoxic controls (P greater than .10). The pulmonary capillary wedge pressure and central venous pressure peaked at ten minutes and then declined gradually over four hours independent of the tonicity of the aspirated fluid. The cardiac output and effective dynamic compliance of the lung dropped rapidly and remained depressed throughout the experiment, and the pulmonary vascular resistance gradually worsened throughout the four hours of study. Similar results occurred with the anoxic controls. The cardiovascular changes that occur with near-drowning and aspiration of water are not dependent on the tonicity of the aspirated fluid but are the direct result of anoxia.

The safety of intraosseous infusions: risks of fat and bone marrow emboli to the lungs

The technique of intraosseous infusion is a life-saving emergency alternative when IV access is impossible or will be critically delayed. Concerns about its safety remain, especially concerning the risk of bone marrow and fat emboli to the lungs. We examined autopsy pulmonary specimens on two children who had received intraosseous infusions during resuscitation attempts and found an average of 0.23 to 0.71 bone marrow and fat emboli per mm2 of lung. We studied normotensive dogs with intraosseous infusions of emergency drugs and solutions into the distal femur. Three dogs were studied with each of the following emergency drugs or solutions: controls with normal saline (0.9% NaCl), epinephrine 0.01 mg/kg, NaHCO3 1 mEq/kg, CaCl 10 mg/kg, atropine 0.01 mg/kg, hydroxyethyl starch 6% in normal saline 10 mL/kg, 50% dextrose in water 0.25 g/kg, and lidocaine 1 mg/kg. Four hours after infusion, the animals were killed, and representative sections of the lung were examined with oil red-0 and hematoxylin and eosin stains for the presence of fat and bone marrow emboli. Fat and bone marrow emboli were found in all lung sections, varying from 0.11 to 4.48 emboli/mm2 lung (mean, 0.91 emboli/mm2 lung) for the emergency drugs and solutions and 0.06 to 0.53 emboli/mm2 (mean, 0.29 emboli/mm2 lung) for the controls. Analysis of variance revealed no significant difference (P = .07) in mean number of fat and bone marrow emboli per square millimeter of lung among the emergency drugs and compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

The syndrome of inappropriate antidiuretic hormone secretion and its effect on blood indices following spinal fusion

Red blood cell indices in four adolescent and preadolescent patients with documented inappropriate antidiuretic hormone secretion (SIADH) following spinal fusion were examined for evidence of dilution. The blood indices in these preoperative patients demonstrated evidence of dilution on both the intracellular and extracellular levels. The major factors causing these dilutional effects were elevated ADH, intravenous fluid overloading, and mobilization of "third space" fluids. It appears that extracellular dilution secondary to these factors results in spuriously low blood indices (namely, hemoglobin, hematocrit, and red blood cells) during the postoperative period. These findings suggest that an awareness of SIADH and avoiding intravenous fluid overloads by accurately managing intraoperative and postoperative fluids will decrease the dilutional effects observed on blood indices and perhaps save patients from unwarranted transfusions.

The safety of cumulative doses of labetalol in perioperative hypertension

Intravenous labetalol is commonly used in the management of hypertensive emergencies or urgencies as well as postoperative hypertension. The maximum recommended dose in any clinical setting is 300 mg in 24 hours. The safety of administering high doses of intravenous labetalol (greater than 300 mg in 24 hours) was evaluated in neurosurgical patients (n = 9). During 15 distinct periods of 24 hours or less, the mean dose of labetalol given was 623 +/- 86 mg. Adverse hemodynamic and biochemical effects were minor and easily reversible. Intravenous labetalol can safely be used in doses exceeding 300 mg per 24 hours in neurosurgical patients.

Computer-assisted audits of blood component transfusion

Comprehensive review of clinical blood transfusion practice at a tertiary-care medical center is complicated by the extraordinary number of patients that receive such therapy. Computer-assisted review of the key objective data used in making the decisions about transfusion is necessary to evaluate the process. Use of 15,873 units of red blood cells, 3,641 units of plasma, 2,619 pools of platelets or pheresis units, and 259 pools of cryoprecipitate was screened by comparing pre-transfusion and post-transfusion blood counts with the medical staff's evaluation criteria. On this basis, 81.4% of transfusion episodes (TEs) were considered fully justified. Medical records were selected for audit from the cases in which the transfusion decisions could not be justified by on-line information. Abstracted data subsequently justified 82 of 139 audited cases; 68.4% of the comments pertaining to the remaining 57 cases adequately explained the transfusion decision. Thus, nearly 96% of the TEs were justifiable as determined by peer review.

Developmental sequelae of long-term infant tracheostomy

The records of 130 children who had had a tracheostomy for more than one month between 1972 and 1982 were reviewed for birth, medical and demographic characteristics, and 32 who were not severely physically or mentally handicapped were followed up at a mean age of 5.5 years. Rates of mortality and morbidity were high, and half of the survivors had moderate to severe intellectual and physical impairments. Even those with the most optimal outcome had significant developmental problems, including slower growth-rate and higher than normal incidences of behavior problems and speech difficulties. Most survivors needed special educational intervention or rehabilitative therapies.

The hemodynamic effects of intravenous labetalol for postoperative hypertension

Hemodynamic data were analyzed from 25 courses of intravenous pulse labetalol therapy for postoperative hypertension in 12 patients after major vascular surgeries. The hemodynamic determinations were obtained an average of 15 minutes after a therapeutic total dose of 10-120 mg of labetalol (mean, 37.5 mg). The mean arterial pressure (MAP) decreased an average of 27 mmHg or 20% after intravenous labetalol. This normalization of the postoperative hypertension was associated with a 19% increase in cardiac output (CO) and cardiac index (CI) (CO mean increase of 0.58 L/min and CI increase of 0.31 L/min/m2). Commensurate with this decrease in MAP and increase in CO was an average decrease in systemic vascular resistance (SVR) of 625 dyne/sec/cm-5 or 25%. The pulmonary vascular resistance decreased 15 dyne/sec/cm-5 or 4%. The heart rate decreased 9 beats per minute or 10% and the left ventricular stroke work improved by 9% or 1.6 g/m2/beat while the right ventricular stroke work increased by 33% or 2.8 g/m2/beat. The hemodynamic responses to intravenous labetalol in these patients were all beneficial, and there were no adverse effects secondary to the pulse doses of labetalol. Labetalol appears to be safe and efficacious for the treatment of postoperative hypertension in patients undergoing major vascular surgery.

Labetalol to control blood pressure after cerebrovascular surgery

Fifteen patients who had undergone neurovascular surgery for arteriovenous malformations or cerebrovascular aneurysms and had intracranial pressure (ICP) monitors were studied. The patients had been treated initially with sodium nitroprusside to maintain their arterial BP in a prescribed range, but, because of excessive nitroprusside dose requirements, they were considered either to have refractory BP or to be at risk for thiocyanate toxicity. Intravenous labetalol therapy was started either by frequent bolus pulse therapy every 1 to 2 h or by continuous infusion therapy. The degree of desired arterial BP control and the effects on ICP and cerebral perfusion pressure (CPP) were assessed and compared with the results during nitroprusside therapy. The degree of arterial BP control with labetalol was assessed to be good; 11 patients were weaned off nitroprusside and the remaining four patients had a substantial reduction in their nitroprusside requirements, needing an average of only 1.5 micrograms/kg.min of nitroprusside to control their BP compared with average requirements of 10 micrograms/kg.min of nitroprusside before labetalol therapy. Labetalol therapy improved CPP in six patients and ICP in five patients, with no significant change in cerebral pressure in the remainder. Overall, the CPP in the 15 patients improved from 63 +/- 15 (SD) mm Hg with nitroprusside to 65 +/- 10 mm Hg with labetalol therapy and the ICP decreased from 11.3 +/- 6.1 mm Hg with nitroprusside to 8.6 +/- 3.1 mm Hg with labetalol therapy (p less than .05 by Wilcoxon matched pairs).(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of a potentially lethal dose isoniazid ingestion

A seven-year-old boy ingested 3,000 mg (125 mg/kg) of isoniazid. Initial blood levels of isoniazid were 250 micrograms/mL approximately six hours after ingestion. Despite IV treatment in the emergency department with 3,000 mg pyridoxine and a repeat of the same antidote one hour later in the intensive care unit, the high isoniazid blood levels and persistent metabolic acidosis and coma prompted a decision to increase drug clearance by hemodialysis. Clearance data confirmed the effectiveness of hemodialysis in removing the poison, and the clinical response was dramatic.

A catch in the Reye

Twenty-six cases of Reye syndrome from The Children's Hospital, Camperdown, Australia, occurring between 1973 and 1982 were reviewed. Of these, 20 cases met the US Public Health Service Centers for Disease Control criteria for the diagnosis of Reye syndrome. Aspirin or salicylate ingestion had occurred in only one of the 20 cases (5%), and paracetamol (acetaminophen) had been administered in only six of the cases (30%). Pathologic confirmation of the diagnosis of Reye syndrome was accomplished in 90% of the cases. The incidence of Reye syndrome in New South Wales, Australia, is estimated from this study to be approximately nine cases per 1 million children compared with recent US data of ten to 20 cases per 1 million children and three to seven cases per 1 million children in Great Britain. The mortality for these Reye syndrome cases in Australia was 45% as compared with a 32% case-fatality rate in the United States. In Australia, the pediatric usage of aspirin has been extremely low for the past 25 years (less than 1% of total dosage units sold), with paracetamol (acetaminophen) dominating the pediatric analgesic and antipyretic market. Reye syndrome may be disappearing from Australia despite a total lack of association with salicylates or aspirin ingestion, since there were no cases found at The Children's Hospital in 1983, 1984, or 1985.

Effects of tonicities of saline solutions on pulmonary injury in drowning

We studied the degree of pulmonary and hemodynamic compromise induced by six saline solutions of varying tonicities (0%, 0.225%, 0.45%, 0.9%, 2%, and 3%) instilled down the trachea. We also attempted to resuscitate the dogs after a simulated wet drowning in each of the solutions, with and without chlorine. A control study with similar degree of anoxia but no fluid in the lungs was also performed. For the pulmonary variables of alveolar-arterial oxygen pressure difference, intrapulmonary shunt fraction, and PaO2/fraction of inspired oxygen, the 0.225% NaCl solution was significantly (p less than .001) less injurious to the lungs, especially compared with sterile water. The 0.225% and 0.45% NaCl solutions were the least disruptive to pulmonary function; the pulmonary injury they produced was similar to injury in the control dogs. Chlorine in the solution at one to two parts per million did not influence the data. The 0.9% (isotonic, normal saline), 2%, and 3% NaCl drowning solutions showed little difference from one another in terms of pulmonary injury. They were significantly (p less than .05) better than sterile water and significantly (p less than .05) worse than the 0.225% and 0.45% NaCl solutions. Sterile water, whether chlorinated or not, was the most injurious to the lungs. The hemodynamic effects of the drowning solutions were explainable solely by the effects of anoxia.

Drowning, near-drowning, and ice-water submersions

Drowning is the second most common cause of accidental death in children. Swimming pools and natural bodies of water close to home present the greatest risk to young children. The single most important step in the treatment of submersion accident victims is the immediate institution of resuscitative measures at the earliest possible opportunity. Ice-water submersion accidents are an important subgroup of near-drowning victims, who at times can defy predictions for outcome after profound anoxic-ischemic insults. Drowning accident prevention is an important public health measure.