Biomedical subjects

D C Hoaglin

Publications and source records attributed to D C Hoaglin.

27 records · Page 2Linked to original sources

PubMed1988

Neuromuscular dysfunction in burns and its relationship to burn size, hypermetabolism, and immunosuppression.

The etiology of neuromuscular (NM) dysfunction following burn injury has not been characterized. NM deficits, together with hypermetabolism and immunosuppression, are debilitating processes which play a key role in the morbidity and mortality of burned patients. This study examined the usefulness of the murine model to replicate clinically observed NM dysfunction. Systemic effects of graded increases in burn size were studied in the acute phase (3 weeks) of burn trauma. Metabolic rates, immune response to dinitrofluorobenzene (DNFB), maximum tension developed by gastrocnemius muscle, and the response of its NM junction to d-tubocurarine (dTc) were the parameters analyzed. Groups of male CF1 mice were given a 20%, 30%, and 50% total body surface area burn and compared to controls. By Day 21 postburn, all the burn groups showed elevated metabolic rates and immunosuppression to the inflammatory antigen DNFB. NM dysfunction evidenced as a significant depression of maximal tension development was observed in the 30% and 50% groups. A threefold increase in the effective dose (ED95) values of dTc was seen only in the 50% burn group. No NM junctional changes were seen in the 20% burn group. These findings are consistent with clinical observations. We conclude that the mouse is a useful model for evaluating NM dysfunction of burns.

Animals↗

PubMed1988

Ionized hypocalcemia after fresh frozen plasma administration to thermally injured children: effects of infusion rate, duration, and treatment with calcium chloride.

A number of cardiac arrests and severe hypotensive episodes have been witnessed associated with the intravenous infusion of fresh frozen plasma (FFP). To clarify the possible role of hypocalcemia, 28 thermally injured anesthetized pediatric patients with massive blood loss were studied to examine the cardiovascular responses (mean arterial pressure [MAP], heart rate, ECG) to 49 infusions of FFP. Rapid, statistically significant reductions in ionized calcium ([Ca2+]) followed each of four rates (1.0, 1.5, 2.0, and 2.5 ml.kg-1.min-1 for 5 minutes) of FFP infusion (P less than 0.0001). The slowest rate resulted in significantly less reduction in [Ca2+] than did the higher infusion rates (P less than 0.002). In five children MAP decreased greater than or equal to 20% below baseline levels, but this was not correlated with rate of FFP administration or decrease in [Ca2+]. The decreases in [Ca2+] and MAP were inversely related to age and unrelated to anesthetic technique. Changes in the Q-oTc interval were not related to [Ca2+]. Adverse cardiovascular responses and reduced [Ca2+] were not significantly different between 5- and 10-minute FFP infusions. Fewer fluctuations in MAP occurred when calcium chloride (CaCl2) was administered; the least fluctuation in [Ca2+] occurred when CaCl2 was administered during the plasma infusion. It is concluded that in thermally injured children 1-17 years old: 1) Rapid infusions of FFP produce sudden but evanescent decreases in [Ca2+]; more rapid infusions result in greater reductions in [Ca2+]. 2) There is no correlation between [Ca2+] and systemic hypotension. 3) Clinically important decreases in MAP occasionally accompany the rapid infusion of FFP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1988

The effect of nail polish on pulse oximetry.

A randomized, blind study examined the effect of nail polish color on measurement of oxygen saturation by pulse oximetry. Fourteen adult volunteers had blue, green, purple, black, and red nail polish applied to their finger nails. A strip-chart recording of oxygen saturation (Nellcor N100) was made in room air and later interpreted in a blinded fashion. The absorption spectra of the five polishes were determined by spectrophotometry. The spectra of nine other nail polishes and three intravenous dyes also were examined. Black, blue, and green nail polish significantly lowered oximeter readings of oxygen saturation. Blue and green produced greater decreases than purple and red; black produced an intermediate decrease. Some but not all nail polishes absorbed light at the wavelengths used by the pulse oximeter (660 nm and 940 nm). The degree of artifactual desaturation correlated best with the difference between absorbance at 660 nm and absorbance at 940 nm (r = 0.95). Spectrophotometric absorbance data suggest that other colors may interfere with pulse oximetry. On the basis of spectrophotometric data, brown-red nail polish was predicted to interfere with oximetry; subsequent pulse oximetry measurements confirmed the prediction. Nail polish should be removed routinely before pulse oximetry monitoring.

Adult↗

PubMed1987

Beta-adrenoceptor blockade, alpha-stimulation and changes in plasma potassium concentration after suxamethonium administration in dogs.

A study involving 20 mongrel dogs tested the hypotheses that beta-adrenoceptor blockade or alpha-adrenoceptor stimulation may potentiate and prolong the increase in plasma potassium concentration after suxamethonium administration, and that the beta effect is beta 2-receptor mediated. Propranolol 0.5 mg kg-1 altered the time to peak increase in plasma concentration of potassium after suxamethonium, but did not increase peak concentrations. In controls, the maximum change (0.83 mmol litre-1) occurred at 3 min, while in propranolol-treated dogs the peak change (0.96 mmol litre-1 occurred at 30 min. Similar results were obtained when metoprolol 0.25 mg kg-1 and ICI 118551 0.1 mg kg-1 were used, respectively, as selective beta 1- and beta 2-adrenoceptor blockers. The increases in potassium concentration following suxamethonium in the metoprolol group (0.98 mmol litre-1) and the ICI 118551 group (0.82 mmol litre-1) reached maximum concentrations at 30 min compared with the controls (0.79 mmol litre-1) which achieved a maximum at 3 min. Phenylephrine was infused at 8 micrograms kg-1 min-1 to produce alpha stimulation. The infusion alone altered plasma concentrations of potassium, but the haemodynamic changes were such that conclusions as to the effect of alpha-stimulation on release of potassium after suxamethonium could not be reached.

Adrenergic beta-Antagonists↗

PubMed1987

Effects of information feedback and pulse oximetry on the incidence of anesthesia complications.

No standard outcome measures exist to evaluate the effect of interventions intended to improve the quality of anesthesia care. The authors established a clinically practical definition of outcome, and used it to assess the effect of feedback of information about complications and the effect of pulse oximetry on the rate and severity of important anesthesia-related problems encountered in the operating room (OR) and recovery room (RR). On admission to the RR, the patient's anesthetist documented Recovery-Room-Impact Events (RRIE), defined as an "unanticipated, undesirable, possibly anesthesia-related effect that required intervention, was pertinent to recovery-room care, and did or could cause at least moderate morbidity." Following a control period with no feedback of data, intense feedback of grouped (anonymous) RRIE rates was provided. Later, pulse oximeters were introduced to all anesthetizing locations. Among 12,088 patients (71% of all RR admissions), 18% had at least one RRIE in the OR or RR. The most common RRIEs were hypotension (4.4%), arrhythmia (3.9%), hypertension (1.5%), intubation difficulties (0.8%), hypoventilation (0.8%), and hypovolemia (0.6%). Feedback of information produced no demonstrable change in the rate of RRIEs. Although significantly fewer patients experienced RRIEs (15.6% vs. 12.4%, P less than 0.0001), hypotensive RRIEs (5.2% vs. 3.8%, P = 0.0003), and hypovolemic RRIEs (0.88% vs. 0.42%, P = 0.0017) following the introduction of pulse oximetry in the OR, confounding factors prevent establishment of a cause-and-effect relationship. Quality assurance may require more direct intervention and individual feedback to be effective. Still, the RRIE measure requires minimal effort at low cost and encourages improved transmission of information at the time of admission to recovery-room care.

Anesthesia↗

PubMed1987

Calcium chloride versus calcium gluconate: comparison of ionization and cardiovascular effects in children and dogs.

A randomized prospective study in both children and dogs compared ionization of calcium chloride and calcium gluconate. Five conditioned dogs under halothane anesthesia received calcium chloride (4, 8, 12 mg/kg) and calcium gluconate (14, 28, 42 mg/kg) intravenously. Ten children scheduled for burn wound excision and grafting received both calcium chloride (2.5 mg/kg) and calcium gluconate (7.5 mg/kg) injected through a central venous cannula. Ionized calcium was measured at 0, 0.5, 1, 3, 5, and 10 min in the children, and 0, 0.5, 1, 2, 3, 4, 5, 10, 20, and 45 min in the dogs. The authors conclude that equal elemental calcium doses of calcium gluconate (10%) and calcium chloride (10%) (approximately 3:1), injected over the same period of time, are equivalent in their ability to raise [Ca++] during normocalcemic states in children and dogs; the changes in [Ca++] following calcium administration are short-lived (minutes); rapidity of ionization seems to exclude hepatic metabolism as an important factor in the dissociation of calcium gluconate; and equivalent rises in [Ca++] produced by calcium gluconate or calcium chloride resulted in equivalent cardiovascular effects. The authors feel that either form of calcium salt would be satisfactory if indicated during cardiopulmonary resuscitation or for the treatment of ionized hypocalcemia due to massive blood transfusion.

Adolescent↗

PubMed1986

Clinical pharmacology of atracurium given in high dose.

The safety and efficacy of atracurium 0.8 mg kg-1 was determined in healthy patients with particular attention to the speed of onset of blockade, and to changes in haemodynamic variables. Atracurium 0.8 mg kg-1 had a shorter onset time than atracurium 0.5 mg kg-1, and satisfactory intubating conditions were achieved earlier. "Priming" produced no significant improvement in onset time or intubating conditions. Onset times were significantly shorter with nitrous oxide-opioid anaesthesia than following thiopentone alone. Although a 0.8-mg kg-1 bolus resulted in a significant reduction in mean arterial pressure to 75% of control and was associated with a significant increase in plasma histamine concentrations, this response could be prevented by injecting the drug over 75 s. "Priming" or a 30-s injection produced no haemodynamic protection. The protection achieved by pretreatment with anti-histamines was incomplete: mean arterial pressure decreased to 83% of control.

Adolescent↗

PubMed1985

Mycobacterium avium complex, an emerging pathogen in Massachusetts.

We report a study of 1,953 patients whose laboratory records from 1972 through 1983 at the Massachusetts Mycobacteria Reference Laboratory indicated the isolation of Mycobacterium avium complex (MAC) organisms. At least one clinical specimen from each patient during this period exhibited the organism. The incidence of isolation of MAC has increased fivefold since 1972, with a doubling of the number of patients with positive MAC specimens from normally sterile sites occurring since 1980. A concomitant increase of more than fourfold in other nontuberculous mycobacteria has occurred. Most isolates came from high-density population centers. Communities whose drinking water comes from a distant rather than a local source were more likely to have patients with MAC.

Adolescent↗

PubMed1985

Effect of prethymectomy plasma exchange on postoperative respiratory function in myasthenia gravis.

The effect of prethymectomy plasma exchange on postoperative mechanical ventilation requirement and length of stay in the intensive care unit were studied retrospectively in 37 patients with myasthenia gravis. We found a significantly decreased time on mechanical ventilation (mean 1.02 +/- 0.40 versus 3.43 +/- 0.60 days) and a shorter stay in the intensive care unit (mean 3.09 +/- 0.99 versus 5.15 +/- 0.66 days) for 11 patients with respiratory weakness who were treated with preoperative plasma exchange compared with 26 patients who did not receive plasma exchange. Patients with respiratory weakness who received prethymectomy plasma exchange required less time on mechanical ventilation (mean 1.02 +/- 0.40 versus 2.73 +/- 0.88 days) and a shorter stay in the intensive care unit (mean 3.09 +/- 0.99 versus 4.46 +/- 1.08 days) than those patients without respiratory weakness who did not receive plasma exchange. Eleven patients met the criteria for plasma exchange but did not receive it. They required significantly more time on mechanical ventilation (mean 4.43 +/- 0.94 versus 1.02 +/- 0.40 days) and in the intensive care unit (mean 6.09 +/- 0.86 versus 3.09 +/- 0.99 days) than patients who received plasma exchange. Our results indicate that patients with severe forms of myasthenia gravis treated with prethymectomy plasma exchange require less mechanical ventilation and less time in the intensive care unit postoperatively.

Adolescent↗