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Biomedical subjects

C G Durbin

Publications and source records attributed to C G Durbin.

36 records · Page 2Linked to original sources
PubMed1994

Sedation in the critically ill patient.

Critically ill patients experience many unpleasant and frightening events while in an ICU. Appropriate concern for pain, discomfort, and anxiety is required from caregivers. The use of reassuring mannerisms, honest communication, and analgesics and sedatives, especially during therapeutic paralysis, improves patient comfort and reduces the morbidity rate. This article reviews the therapeutic options for sedation and experience with these agents in the critically ill.

Anesthetics↗
PubMed1993

Optimal atrioventricular (AV) pacing interval during temporary AV sequential pacing after cardiac surgery.

Temporary dual chamber atrioventricular (AV) pacing is often used to increase cardiac output (CO) after cardiac surgery. The AV interval was varied to investigate the effect on CO in 13 patients. CO was computed from the Fick principle using mixed venous oxygen saturation (SvO2), arterial oxygen saturation (SaO2), hemoglobin, and oxygen consumption (VO2). AV intervals were varied randomly from 0.025 to 0.300 seconds in 0.025-second increments. The effect on CO from increasing the AV interval was dependent on the control CO. In all patients, as the AV interval was increased from 0.025 to 0.100 seconds, CO progressively increased. In most patients, the highest (optimal) CO occurred with AV pacing and averaged 300 mL/min greater than with atrial (A) pacing alone (P < .0001). In patients with a high initial CO (> 6.0 L/min), CO peaked and averaged 0.5 L/min more than with A pacing. CO was maximal for each of these patients at a unique AV interval between 0.100 and 0.225 seconds, and at intervals greater than 0.225 seconds CO decreased (P < .01). In patients with intermediate CO (4-6 L/min) at AV intervals greater than 0.100 seconds, a plateau in CO was reached. No consistent pattern was seen in patients with low initial CO (< 4.0 L/min). Maximal CO may be achieved by optimizing the AV interval in patients following cardiac surgery. The optimal AV interval is between 0.100 and 0.225 seconds and is different for each patient. Continuous SvO2 monitoring allows rapid evaluation of CO changes and optimization of the AV pacing interval.

Atrioventricular Node↗
PubMed1993

A case-control study of patients readmitted to the intensive care unit.

OBJECTIVE: To determine characteristics of patients requiring readmission to an intensive care unit (ICU). DESIGN: Retrospective case-control chart review. SETTING: Adult patients in an 8-bed medical and 16-bed surgical ICU in a 650-bed university teaching hospital during an 18-month period. INTERVENTIONS: None. METHODS: Each patient readmitted to either ICU was compared to a single control patient matched for age, sex, unit, and diagnosis. A total of 117 variables were obtained from chart review. The last value for each variable before ICU discharge was used. Chi-square analysis, linear regression factor analysis, correlation, and Student's t-test were used to identify significant factors predicting the patient's return to an ICU. Descriptive statistics were used to describe various subgroups. RESULTS: Mortality rate was 41.5% in the 82 readmitted patients (comprising 4.6% of the total ICU admissions) and only 7.3% in the controls. Mean (+/- SD) hospital length of stay was 47.8 +/- 42.0 days in the study group and 20.8 +/- 14.2 days (p < .0009) in the controls. Initial ICU length of stay was 8.3 +/- 16.1 days in the readmitted group and 4.0 +/- 5.0 days (p = .02) in the controls. Variables that predicted readmission to the ICU were: increased respiratory rate (24.2 vs. 20 breaths/min, p < .002), lower hematocrit value (31.9% vs. 34.4%, p = .01), positive fluid balance (p < .03), and positive blood cultures (six in the readmitted group, none in the controls, p = .002). More than 30% of readmissions were for a recurrence or worsening of the original problem. Fifty-four percent of the patients were readmitted with pulmonary failure. Mortality rate in both groups was related to advanced age, Acute Physiology and Chronic Health Evaluation (APACHE II) scores at ICU discharge, and increased blood urea nitrogen concentrations. Mortality rate in the control group, but not in the readmitted group, correlated with the level of consciousness, serum creatinine concentration, and use of hemodialysis. CONCLUSIONS: Readmission to an ICU carries a risk of high mortality rate and increased length of stay and may represent premature discharge in at least 30% of patients. Pulmonary failure is the immediate cause of readmission in more than half of the readmitted patients. Increased respiratory rate correlates with ICU readmission. Intermediate care areas for patients with poor pulmonary function may help to avoid readmission to an ICU, prevent death, and conserve hospital resources.

Case-Control Studies↗
PubMed1993

Selective application of cardiopulmonary resuscitation improves survival rates.

This study is a retrospective review of all patients who died without cardiopulmonary resuscitation (CPR) or who sustained a sudden cardiopulmonary arrest in the hospital and received CPR during a 2-yr period at a large medical center. Based on a review of Current Procedural Terminology codes, patients were classified into one of the ten disease categories: multiple medical problems, acute disease, procedure-related, congenital disease, neoplasm, metastatic neoplasm, trauma, burn, acquired immunodeficiency syndrome, and dementia. A total of 1206 patient deaths without a CPR effort were identified. CPR was administered to another 550 patients who had a sudden cardiopulmonary arrest, of which 71% survived the resuscitative attempt initially, but only 25% survived CPR until discharge from the hospital. CPR was applied less frequently than the mean in the metastatic neoplasm (P < 0.0001), trauma (P = 0.013), and dementia (P = 0.0003) groups and more frequently in the acute disease (P < 0.0001) and procedure-related (P < 0.0001) groups. Survival to discharge from the hospital was more frequent than the mean in the congenital disease group (P = 0.0004) and less frequent in the neoplasm group (P = 0.0425). The other groups had survival rates comparable to the mean. Patients 70 yr of age and older were less likely to receive CPR than those younger than 70 (P < 0.0001). However, if they did receive CPR, they were just as likely to survive to discharge from the hospital as the younger patients (P = 0.3404).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Attitudes of anesthesiology residents toward critical care medicine training.

The number of anesthesiology residents pursuing critical care medicine (CCM) fellowship training has been decreasing in recent years. A significant number of training positions remain unfilled each year. Possible causes of this decline were evaluated by surveying residents regarding their attitudes toward practice and training in CCM. All 38 anesthesiology programs having accredited CCM fellowships were surveyed. Four of these and one program without CCM fellowships were used to develop the survey instrument. Four programs without CCM fellowships and 34 programs with CCM fellowships make up the survey group. Returned were 640 surveys from 37 (97%) programs accounting for over 30% of the possible residents. Resident interest in pursuing CCM training decreased as year of residency increased (P < 0.0001). Residents in programs with little patient care responsibility during intensive care unit (ICU) rotations expressed less interest in CCM training (P < 0.012). The administrative role of the anesthesiology department in the ICU also influenced resident interest (P < 0.014). Written responses to open-ended questions suggested resident concerns with the following: stress of chronic care, financial consequences of additional year of training, ICU call frequency and load, ICU role ambiguity, and shared decision-making in the ICU. A recurring question was, "Are there jobs (outside of academics) for anesthesiologist intensivists?" Most residents knew a CCM anesthesiologist they admired and knew that there were unfilled fellowship positions available. Defining the job market, improving curriculum and teaching, supporting deferment of student loans, and introducing residents and medical students to the ICU earlier may increase the interest in CCM practice among anesthesiology residents.

Anesthesiology↗
PubMed1992

Influence of political power, medical provincialism, and economic incentives on the rationing of surgical intensive care unit beds.

OBJECTIVE: To determine factors influencing rationing decisions in a surgical ICU during a temporary nursing shortage when two to six of the unit's 16 beds were closed. DESIGN: Blinded, concurrent data collection, retrospective chart review. SETTING: Surgical ICU. PATIENTS: All patients (n = 308) for whom a surgical ICU bed was requested were studied during a 3-month period. MEASUREMENTS AND MAIN RESULTS: Admitting patterns did not change and no attempts were made to limit admissions to more severely ill patients during times of the greatest shortage of surgical ICU beds. Contrary to findings in previous reports, the severity of illness of patients admitted to the surgical ICU decreased as bed availability and bed census decreased. Bed allocation across surgical services was influenced by factors other than medical suitability. Of major users, cardiothoracic surgery experienced the highest percentage (59%) of all patient admissions and lowest percentage (1.6%) of all denied admissions. General surgery experienced the lowest percentage (15%) of all admissions and highest percentage (10.4%) of all denied admissions, although these patients had the highest average Acute Physiology and Chronic Health Evaluation (APACHE II) scores for all patients admitted (17.7) and for patients denied admission (15.8). CONCLUSIONS: Surgical attending physicians rarely used other open inhouse ICU beds when surgical ICU beds were unavailable. Political power, medical provincialism, and income maximization overrode medical suitability in the provision of critical care services.

Adult↗
PubMed1992

The effect of respiratory care department management of a blood gas analyzer on the appropriateness of arterial blood gas utilization.

We investigated the effects of establishing a blood gas analysis service controlled by respiratory care practitioners (RCPs) on the appropriateness of arterial blood gas (ABG) sampling. An ABG analyzer was placed outside the surgical intensive care unit (SICU) and only RCPs were permitted to process samples on it. In 1-month and 1-year follow-up audits of appropriateness of ABG analysis, the nursing staff improved from 42% appropriate to 73% appropriate in both follow-up periods. RCPs maintained a high degree of appropriateness in all periods (90%, 87%, and 91%), although the percentage of the total ABGs performed by RCPs increased. Additional benefits included a better mutual understanding of each caregiver's role and work load, more collaboration among caregiver groups, and caregiver's perception of improved patient care.

Blood Gas Analysis↗
PubMed1990

The range of pulmonary artery catheter balloon inflation pressures.

Pulmonary artery catheters are frequently used and may be the cause of pulmonary artery rupture. The "feel" of balloon inflation, a clinical sign of a "wedged" catheter, was noted to vary among different manufacturers' catheters. The inflation pressures of five catheters from four manufacturers were examined in the laboratory. Peak pressures ranged from 475 +/- 10 mm Hg to 1,037 +/- 36.8 mm Hg. Plateau pressures ranged from 220 +/- 4 mm Hg to 495 +/- 2.9 mm Hg. Catheters with high inflation pressures may make detection of a wedged catheter by feel impossible and, thus, may increase the risk of a pulmonary artery rupture.

Analysis of Variance↗
PubMed1989

Pulmonary artery catheter deterioration during hydrochloric acid infusion for the treatment of metabolic alkalosis.

Hydrochloric acid (HCl) infusions for the correction of metabolic alkalosis have been used for 20 yr. In the critical care setting, HCl is usually infused through a central venous or pulmonary artery (PA) catheter. In two patients receiving HCl infusions through a PA catheter, we observed and examined solid yellow particulate material in the aspirating syringe while testing the proximal lumen for patiency. We carried out in vitro investigation infusing PA catheters with 0.1, 0.2, 0.3, and 0.4 normal HCl at 20 degrees, 38 degrees, and 42 degrees C for 24 and 48 h. Although frank catheter deterioration could not be documented, the surface and interior of those catheters infused with greater than 0.1 normal HCl changed texture, indicating a change in catheter composition. Exceeding a concentration of 0.1 normal is not recommended when HCl is infused through PA catheters.

Alkalosis↗
PubMed1986

Effects of dantrolene and verapamil on atrioventricular conduction and cardiovascular performance in dogs.

The effects of intravenous dantrolene sodium, alone and in combination with verapamil, upon atrioventricular conduction, cardiovascular function, and neuromuscular function were studied in chloralose-urethane anesthetized dogs. Hemodynamic variables (systemic arterial, central venous, and pulmonary arterial pressures and cardiac output) and His-bundle electrograms were monitored, and measurements were made during atrial pacing at 175 beats/min, as well as at the spontaneous heart rate. In one part of the study animals received dantrolene sodium incrementally at 30-min intervals to cumulative doses of 1, 2.5, 5, and 10 mg/kg. Subsequently, verapamil was administered incrementally at 30-min intervals to cumulative doses of 0.1, 0.2, 0.4, and 0.6 mg/kg. In the second part of the study, dogs received identical dosage sequences, but verapamil preceded dantrolene administration. Dantrolene caused no significant depression of atrioventricular conduction or cardiac performance but did increase systemic vascular resistance at doses above 2.5 mg/kg. Verapamil alone (greater than or equal to 0.2 mg/kg) or with dantrolene (greater than or equal to 0.1 mg/kg) increased the atrial-His-bundle conduction interval. In the presence of verapamil, dantrolene (greater than or equal to 2.5 mg/kg) decreased cardiac index and increased pulmonary artery occlusion pressure. Although 0.6 mg/kg verapamil depressed cardiac index and increased pulmonary artery occlusion pressure, this effect was observed at 0.4 mg/kg after prior treatment with dantrolene. Verapamil did not augment the dose-dependent twitch depression observed with dantrolene. Dantrolene alone had no apparent effect on atrioventricular conduction and caused little enhancement of the effects of verapamil. However, each drug appeared to enhance the myocardial depressant effects of the other.

Animals↗
PubMed1982

Cardiovascular effects of nalbuphine in patients with coronary or valvular heart disease.

Although the hemodynamic changes produced by small doses of nalbuphine given to patients with cardiac disease are minimal, the cardiovascular effects of large doses which have been used as supplements for general anesthesia have not been investigated. Cardiovascular variables were measured after incremental doses of nalbuphine, up to 2 or 3 mg/kg in fourteen patients with coronary artery disease with normal left ventricular function and in seven patients with mitral valve disease. No significant changes in cardiac index, stroke work index, mean arterial pressure, pulmonary diastolic or wedge pressure, heart rate, or central venous pressure occurred in the preoperative period. However, nalbuphine alone did not produce surgical anesthesia and the addition of diazepam, nitrous oxide, or halothane was required in all patients. The addition of halothane coupled with surgical stimulation significantly decreased cardiac and stroke indices, increased mean arterial and pulmonary wedge pressures, and increased systemic vascular resistance in patients with coronary artery disease. In patients with mitral valve disease, following surgical incision, there were small but significant decreases in cardiac index and left ventricular stoke work index, and increases in systemic vascular resistance. Despite its lack of deleterious hemodynamic effects, the place of nalbuphine in the armamentarium of the anesthesiologist must be limited to use as a premedicant, as an adjunct to balanced anesthesia, or for postoperative pain relief.

Adult↗
PubMed1979

A laboratory animal model for malignant hyperpyrexia.

Strandard laboratory rabbits which are not genetically susceptible to malignant hyperpyrexia were anesthetized with either halothane or pentobarbital. Administration of caffeine in 125 mg increments produced a syndrome strongly resembling malignant hyperpyrexia in rabbits anesthetized with halothane. All these animals became rigid, hyperpyrexic, acidotic and hyperkalemic, whereas caffeine-treated, pentobarbital-anesthetized animals developed only mild acidosis. Pentobarbital alone and halothane alone caused no changes in measured variables. This model for malignant hyperpyrexia resembles the naturally occurring disease more closely than several preceding pharmacologic models.

Anesthesia↗