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Biomedical subjects

C N Sessler

Publications and source records attributed to C N Sessler.

34 records · Page 2Linked to original sources
PubMed1991

In situ pulmonary vascular perfusion for improved recovery of pulmonary intravascular macrophages.

The microcirculation contains mononuclear phagocytes, with features characteristic of macrophages, adhered to luminal capillary surfaces by intercellular adhesion plaques. These pulmonary intravascular macrophages may play an important role in regulating lung vascular tone and capillary permeability, and may modulate capillary endothelial cell growth and replication by the secretion of soluble mediators (i.e., arachidonate metabolites, cytokines). This study describes a technique which utilizes in situ lung perfusion to remove intravascular macrophages in large numbers from the microcirculation of porcine lung (n = 26). This technique yielded 3.8 +/- 0.5 x 10(8) (mean +/- SEM) mononuclear cells which were highly phagocytic toward particulate carbon (phagocytic index, 80 +/- 6%). Harvested mononuclear phagocytes reestablished intercellular adhesion plaques when placed on small vessel porcine pulmonary artery endothelial cell monolayers and exhibited histochemical characteristics typical of monocyte/macrophage lineage cells. Mononuclear cells obtained from lung microcirculation displayed size heterogeneity varying from 10.4 to 16.5 microns in diameter. Both large and small cell populations phagocytosed particulate carbon. Morphometric studies performed on collagenase-treated lung demonstrated that in situ perfusion removed significant numbers of intravascular macrophages in lung capillaries. The technique described permits the rapid removal of anchored mononuclear phagocytes from lung capillaries with minimal postmortem delay.

Animals↗
PubMed1990

Theophylline toxicity: clinical features of 116 consecutive cases.

PURPOSE: To examine the predisposing factors, clinical and laboratory characteristics, management, course, and outcome of consecutive cases of theophylline toxicity in an outpatient setting. PATIENTS AND METHODS: Toxicology records and hospital charts of consecutive patients with a serum theophylline concentration (STC) greater than 30 mg/L (167 mumol/L) identified in the emergency departments (EDS) of a University Medical Center and a Veterans Administration Medical Center were reviewed. RESULTS: Ten percent and 2.8% of 5,557 consecutive STCs measured in the EDs over 2 years were greater than 20 mg/L (111 mumol/L) and greater than 30 mg/L (167 mumol/L), respectively. One hundred sixteen cases with STC greater than 30 mg/L were identified. Fourteen (12%) and 102 (88%) were due to acute overdose and chronic overmedication, respectively. Principal predisposing factors included patient and/or physician dosing errors and conditions or medications that reduce theophylline clearance. One or more toxic manifestations were present in 109 (94%) cases. Fifty percent of patients had mild toxicity, 38% had moderate toxicity, and 7% had severe or life-threatening toxicity. Seven (6%) patients died when STC was still in the toxic range and/or as a result of toxicity. Acute overdose was associated with higher peak STC (p less than 0.001), younger age (p less than 0.01), and greater mortality (p less than 0.05) than chronic overmedication. Peak STC correlated significantly with the severity of toxicity for patients with acute overdose (p less than 0.01) but not for patients with chronic overmedication. All three patients with acute overdose and fatal toxicity had peak STCs greater than 100 mg/L (555 mumol/L) and fulminant toxicity, whereas the four patients with chronic overmedication who died during toxicity had peak STCs in the 40 to 60 mg/L (222 to 333 mumol/L) range and most died of respiratory failure rather than directly from toxicity. Patients with acute overdose who had the delayed onset of severe or life-threatening toxicity and/or died from toxicity were accurately identified using previously published criteria for prophylactic charcoal hemoperfusion. In contrast, the predictive value of the criteria applied to patients with chronic overmedication was poor. Two patients with acute overdose underwent charcoal hemoperfusion, but died. No patient with chronic overmedication received charcoal hemoperfusion. CONCLUSION: Toxic-range STCs are relatively common in the ED population, occur primarily as a result of patient and physician dosing errors, and cause a broad range of toxic manifestations of varying severity. Peak STC correlates with the severity of toxicity and outcome for acute overdose but not chronic overmedication intoxication. Previously published criteria for prophylactic charcoal hemoperfusion accurately identify patients with acute overdose but not patients with chronic overmedication at risk for serious complications and death.

Adolescent↗
PubMed1990

Cardiac arrhythmias during theophylline toxicity. A prospective continuous electrocardiographic study.

To examine the effects of theophylline toxicity on cardiac rhythm, patients underwent continuous ambulatory ECG recording during acute theophylline toxicity and recovery. The patients, who were recruited form inpatient wards, intensive care units, and emergency departments of a University Medical Center and a Veterans Administration Medical Center, had serum theophylline concentrations (STC) greater than 30 mg/L. There were 14 men and two women with a mean age of 66 years. Fourteen patients had COPD and developed toxicity following long-term theophylline overmedication. Two patients had asthma and ingested an intentional overdose. The STC at the onset of ECG recording ranged from 23 to 67 mg/L. The principal rhythm was sinus in 15 patients; one patient had atrial fibrillation. Sinus tachycardia (heart rate greater than 100/min) was common, and heart rate fell in proportion to STC as toxicity resolved. Supraventricular ectopic beats (SVEs) were noted in seven patients with multiple runs of SVE being present in four. One patient developed multifocal atrial tachycardia (MAT) during toxicity that resolved spontaneously. During the 11 +/- 8 hours of recording during toxicity (STC greater than 20 mg/L), 80 percent of patients had ventricular premature beats (VPBs), 44 percent had paired VPBs, and 25 percent had ventricular runs. One elderly patient with heart disease developed sustained ventricular tachycardia (VT) when STC = 66 mg/L. No other patient had ventricular ectopy that required intervention. During the 10 +/- 6 hours of recording during the "recovery phase" (STC less than 20 mg/L), all patients with VPBs continued to have ectopy; however, the number of VPBs declined significantly. A follow-up 24-hour ECG recording obtained one week after recovery from toxicity in the patient with sustained VT demonstrated marked reduction in the frequency and complexity of VPBs. Patients with frequent (greater than 10/h) or repetitive VPBs were older (p less than 0.05) than those without complex ectopy. There was a trend (p = 0.07) suggesting patients with underlying heart disease were at risk for having complex ventricular ectopy. We conclude that sinus tachycardia, SVE, and VPBs are common among patients with theophylline toxicity; however, sustained ventricular or supraventricular tachyarrhythmias that require antiarrhythmic therapy are uncommon.

Acute Disease↗
PubMed1989

Transient pulmonary perfusion scintigraphic abnormalities in pulmonary air embolism.

A critically ill man suffered a respiratory arrest due to pulmonary air embolism after the exchange of central venous catheters over a guidewire. A pulmonary perfusion lung scan performed 90 min later demonstrated extensive perfusion defects which were interpreted as "high probability" for PTE. Pulmonary angiography 4.5 h later was normal. A second perfusion lung scan performed 24 h after the respiratory arrest was normal. Pulmonary air embolism can produce segmental (and larger) perfusion defects which may be indistinguishable from those caused by PTE. The rapid (24 h) resolution of the perfusion defects may help differentiate the two disorders.

Catheterization, Central Venous↗
PubMed1988

Effects of platelet-activating factor antagonist SRI 63-441 on endotoxemia in sheep.

We investigated whether platelet-activating factor (PAF) mediates endotoxin-induced systemic and pulmonary vascular derangements by studying the effects of a selective PAF receptor antagonist, SRI 63-441, during endotoxemia in sheep. Endotoxin infusion (1.3 micrograms/kg over 0.5 h) caused a rapid, transient rise in pulmonary arterial pressure (Ppa) from 16 +/- 3 to 36 +/- 10 mmHg (P less than 0.001) and pulmonary vascular resistance (PVR) from 187 +/- 84 to 682 +/- 340 dyn.s.cm-5 (P less than 0.05) at 0.5 h, followed by a persistent elevation in Ppa to 22 +/- 3 mmHg and in PVR to 522 +/- 285 dyn.s.cm-5 at 5 h in anesthetized sheep. Arterial PO2 (PaO2) decreased from 341 +/- 79 to 198 +/- 97 (P less than 0.01) and 202 +/- 161 Torr at 0.5 and 5 h, respectively (inspired O2 fraction = 1.0). SRI 63-441, 20 mg.kg-1.h-1 infused for 5 h, blocked the early rise in Ppa and PVR and fall in PaO2, but had no effect on the late phase pulmonary hypertension or hypoxemia. Endotoxin caused a gradual decrease in mean aortic pressure, which was unaffected by SRI 63-441. Infusion of SRI 63-441 alone caused no hemodynamic alterations. In follow-up studies, endotoxin caused an increase in lung lymph flow (QL) from 3.8 +/- 1.1 to 14.1 +/- 8.0 (P less than 0.05) and 12.7 +/- 8.6 ml/h at 1 and 4 h, respectively. SRI 63-441 abolished the early and attenuated the late increase in QL.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Worsening oxygenation in the mechanically ventilated patient. Causes, mechanisms, and early detection.

Hypoxemia or worsening oxygenation is a common problem in the ICU. Ventilator-related problems, patient-related problems, including progression of the underlying disease process or superimposed disorders, and interventions, procedures, and medications can all adversely affect the patient's oxygenation status. Each of these causes should be sought for in a rapid and expeditious manner and appropriate corrective actions taken.

Equipment Failure↗
PubMed1987

Poor tolerance of oral activated charcoal with theophylline overdose.

Vomiting is a common manifestation of theophylline toxicity and may limit the tolerance of orally administered activated charcoal (OAC). However, this potentially important interaction has received little attention. The records of 33 consecutive patients who presented to the emergency department with serum theophylline concentrations greater than 30 micrograms/ml and toxic symptoms and who were treated with OAC were reviewed. Seventeen (22%) of the 76 OAC doses were vomited. Six patients who had ingested theophylline as a single acute overdose vomited all 11 OAC doses administered, whereas 27 patients receiving chronic theophylline therapy vomited only six (11%) of 65 OAC doses. Vomited doses were associated with higher serum theophylline concentrations. Although theophylline-related vomiting preceded OAC intolerance in all acute toxicity patients, this condition was not predictive of OAC vomiting for chronic toxicity patients.

Administration, Oral↗
PubMed1987

Central venous cannulation done by house officers in the intensive care unit: a prospective study.

Central venous cannulation (CVC) is a procedure frequently performed by house staff in the intensive care units of teaching hospitals. In the medical ICUs of our two hospitals, CVC was successfully done by house officers in 172 cases requiring 231 attempts (one operator at one insertion site), for a success rate of 74%. There were 14 complications (6.1%), five requiring intervention, but none fatal. The overall success rate was higher for the internal jugular approach and lower for the external jugular approach than for other sites. The success rate for Swan-Ganz catheterization was higher for the internal jugular than for the subclavian approach. CVC during resuscitation was frequently unsuccessful (41%) and/or complicated (13.6%). Although success rates were comparable, complications were more common among experienced house officers than among interns, perhaps reflecting patient selection. There was a trend toward fewer and/or less severe complications during the course of the month and of the study.

Adult↗
PubMed1987

Protamine sulfate causes pulmonary hypertension and edema in isolated rat lungs.

The polycation protamine sulfate increases microvascular permeability in the kidney by reducing glomerular charge. We have exposed the pulmonary vasculature to protamine sulfate to determine whether electrical charges play a role in protein permeability in lung vascular beds. In anephric rats, protamine sulfate increased hematocrit approximately 25%. With protamine sulfate doses of 0.08 and 0.04 mg/g body wt, lung blood-free wet-to-dry weight ratios were increased (5.24 +/- 0.8 and 4.89 +/- 0.7) compared with control (3.85 +/- 0.3) (P less than 0.05). In isolated, ventilated, and perfused lungs 0.04 mg/g body wt protamine sulfate increased pulmonary arterial pressure from 5.2 +/- 1.4 to 16.3 +/- 3.9 mmHg (P less than 0.01). These lungs gained weight and lung wet-to-dry weight ratios were significantly increased (15.33 +/- 4.26 compared with 6.04 +/- 0.24 for control lungs). Poly-L-lysine, another polycation, also caused significant increases in pulmonary arterial pressure, lung weight, and lung wet-to-dry weight ratios. The addition of diphenhydramine to the perfusate 10 min before the addition of protamine sulfate did not prevent these changes. Heparin (90 U/mg protamine sulfate) reversed the abnormalities. Pulmonary arterial pressure (7.0 +/- 1.1 mmHg) was not significantly different from the control value, lung weight did not increase, and the lung wet-to-dry weight ratio was 6.24 +/- 0.23 (P greater than 0.05). We conclude that polycations have a significant effect on pulmonary vascular resistance and perhaps on permeability.

Animals↗
PubMed1985

Treatment of theophylline toxicity with oral activated charcoal.

We treated 14 patients who had an initial serum theophylline concentration greater than 30 micrograms/ml (48.3 +/- 19.4 micrograms/ml) and symptoms of theophylline toxicity with oral activated charcoal (OAC). Thirty-gram doses of OAC were administered approximately every two hours for two to four doses. Ten patients tolerated OAC and demonstrated a reduction in theophylline half-life to 5.6 +/- 2.5 hours with resolution of symptoms. Three of these ten patients were treated in the emergency department and discharged, making hospitalization unnecessary. The four patients with the highest initial theophylline concentrations (76.6 +/- 17.7 micrograms/ml) vomited all doses of OAC. Three of these four patients were treated with charcoal hemoperfusion with a reduction in the half-life to 5.2 +/- 1.0 hours. These data support the use of OAC as the primary therapeutic modality in the management of patients with theophylline toxicity. Patients with very high theophylline concentrations (greater than 50 micrograms/ml), however, usually vomit the OAC and may require charcoal hemoperfusion.

Administration, Oral↗
PubMed1983

Lyme disease in North Carolina.

We report two cases of Lyme disease in North Carolina, further expanding the distribution of known sporadic cases of this predominantly northeastern problem in southern states. Physicians in areas where Lyme disease has traditionally not been recognized should be alerted to its characteristic rash (erythema chronicum migrans), tick vector (Ixodes species), possible severe manifestations (neurologic, arthritic, and cardiac), and response to appropriate antibiotic therapy (penicillin or tetracycline).

Adolescent↗
PubMedDate not supplied

Validation of a cognitive test for delirium in medical ICU patients.

Patients with delirium, dementia, depression, and schizophrenia were administered a newly developed test designed to identify delirium in an intensive care unit (ICU) setting. Two alternate forms of the Cognitive Test for Delirium (CTD) were highly correlated. The delirium patients performed least well, and an optimal cutoff score derived from relative-operating characteristic analysis resulted in a sensitivity of 100% and a specificity of 95%. In a follow-up study, the Mini-Mental State Exam could not be administered to 42% of the ICU patients who completed the CTD. Early identification of delirium with the CTD may lead to timely treatment of specific etiologic conditions and a reduction in mortality and morbidity.

Aged↗