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Biomedical subjects

A Perel

Publications and source records attributed to A Perel.

At least 19 recordsLinked to original sources
PubMed2000

The effect of full protective gear on intubation performance by hospital medical personnel.

OBJECTIVE: To assess the influence of protective gear on intubation performance. DESIGN: Prospective, controlled measurement of duration and quality of intubations performed on mannequins by medical personnel with and without protective gear in a crossover design. PARTICIPANTS: Eight teams each comprising an anesthesiologist and a nurse. RESULTS: Intubation duration with and without chemical warfare gear was 69.2 +/- 7 and 47.3 +/- 6 seconds (mean +/- SEM), respectively (p < 0.05). Moreover, rating of intubation quality as "very good" by the anesthesiologists declined significantly from 62.5% without chemical warfare protective gear to 6.25% with the garment and mask. Tube fixation was the rate-limiting step when performed with protective gear (p < 0.05); it was assessed by 81% of the anesthesiologists as the critical step. A learning curve was not observed during the study. CONCLUSION: Protective gear causes a significant prolongation of intubation duration; however, endotracheal intubation can be performed effectively. Technical improvements are warranted for tube fixation because it is the critical step.

Adult↗
PubMed1999

The pharmacokinetics of morphine and lidocaine in critically ill patients.

OBJECTIVE: To evaluate the pharmacokinetic parameters of morphine and lidocaine after a single intravenous dose in critically ill patients. DESIGN: Prospective, clinical study. SETTING: General intensive care unit (ICU) in a university hospital. PATIENTS: Patients admitted to the ICU with severe systemic inflammatory response syndrome of various etiologies. INTERVENTIONS: A single intravenous dose of morphine (0.025 mg/kg) and lidocaine (1.5 mg/kg) were given separately 12-36 h after admission, and arterial blood samples for serum drug levels were taken. MEASUREMENTS AND RESULTS: Morphine pharmacokinetics were studied in 30 patients. The clearance (Cl) was found to be 5.7+/-2.3 ml/kg per min, volume of distribution of the central compartment (Vc) 0.16+/-0.12 l/kg and volume of distribution at steady state (Vss) 1.08+/-0.69 l/kg. These values are lower then those described previously for healthy volunteers (33.5+/-9 ml/kg per min, 1.01+/-0.31 l/kg, and 5.16+/-1.4 l/kg, respectively), and similar to those described in trauma and burned patients. Lidocaine pharmacokinetics were tested in 24 subjects. The Cl was 6.9+/-3.8 ml/kg per min, Vc 0.25+/-0.1 l/kg and Vss 0.78+/-0.26 l/kg. These values are not different from parameters published previously for healthy volunteers (10 ml/kg per min, 0.53 l/min and 1.32 l/min, respectively). No correlation was found between clinical variables and pharmacokinetic parameters of both drugs (ANOVA). CONCLUSIONS: Both morphine and lidocaine have a reduced volume of distribution in critically ill patients. The normal lidocaine clearance indicates preserved hepatic blood flow and suggests that other mechanisms are involved in the reduced morphine clearance. These findings may have application for the treatment of ICU patients.

Adult↗
PubMed1999

The pharmacokinetics of morphine and lidocaine in nine severe trauma patients.

STUDY OBJECTIVE: To study the pharmacokinetic parameters of morphine and lidocaine after a single intravenous (i.v.) bolus in severe trauma patients. DESIGN: Clinical case study. SETTING: Department of Anesthesiology and Intensive Care of a university hospital. PATIENTS: Nine patients, ages 24 to 91 years (mean 54.4 yrs), admitted to the hospital with severe trauma (Injury Severity Score > 20) were included in the study. INTERVENTIONS: After initial evaluation and stabilization, a single i.v. dose of morphine 0.025 mg/kg and lidocaine 1.5 mg/kg was given separately, and blood samples were drawn for each drug serum concentration. MEASUREMENTS AND MAIN RESULTS: Morphine pharmacokinetics was studied in eight patients, lidocaine pharmacokinetics in seven patients, and both drugs were studied in six patients. Morphine clearance 2.5 to 10 ml/kg/min (6 +/- 2.6, mean +/- SD) and volume of distribution 0.28 to 3.30 L/kg (1.4 +/- 1.0) were found to be lower than values described previously for healthy volunteers (33.5 +/- 9 ml/kg/min and 5.16 +/- 1.40 L/kg, respectively), and are similar to those described in trauma patients (5 +/- 2.9 ml/kg/min and 0.9 +/- 0.2 L/kg, respectively). In contrast, lidocaine clearance 4.5 to 9.4 ml/kg/min (6.7 +/- 1.7) and volume of distribution 0.39 to 1.20 L/kg (0.72 +/- 0.28) were similar to the value described in healthy volunteers (10 ml/kg/min and 1.32 L/kg, respectively). CONCLUSION: Changes in pharmacokinetics of drugs eliminated by the liver may occur in patients with severe trauma. The preserved lidocaine clearance indicates an almost normal hepatic blood flow and suggests that other mechanisms may be involved in the lower morphine clearance. The findings may have applications for the treatment of severe trauma patients and suggest that drug monitoring might be needed in some instances so as to avoid toxicity.

Adult↗
PubMed1999

A profile of multiple sclerosis: the New York State Multiple Sclerosis Consortium.

We have obtained a current profile of multiple sclerosis York State through a centralized patient registry and standardized data collection instrument associated with the New York State Multiple Sclerosis Consortium of 12 MS centers located throughout the state. Data from the first 3019 patients with clinically definite MS revealed a clear relationship between MS disease type, duration of disease, and severity of physical disability. Patients with relapsing disease had disease durations approximately half as long as those with progressive forms of the disease (means approximately 6 years versus 11 years). The majority of patients with relapsing disease had Expanded Disability Status Scale (EDSS) scores of 4.0 or less (self-sustained, fully ambulatory), whereas the majority of patients with progressive disease types had EDSS scores of 6.0 or greater (at least unilateral assist for walking). These findings emphasize the importance of early intervention in patients with relapsing disease to slow or prevent the accumulation of physical disability associated with progressive types of disease. Progressive disease was associated with lack of full-time employment and being disabled before the age of 60 years. Patients with relapsing disease were more likely to be employed and have private forms of insurance, whereas patients with progressive types of disease were more likely to have government-supported insurance to cover medical expenses.

Adult↗
PubMed1999

Elevated plasma atrial natriuretic peptide levels after occlusion of the thoracic aorta.

STUDY OBJECTIVE: The influence of occlusion of the thoracic aorta by an intraluminal balloon on plasma atrial natriuretic peptide (ANP) levels was evaluated in humans. METHODS: The changes in plasma ANP and plasma norepinephrine levels, and hemodynamic parameters were measured in 10 patients under general anesthesia undergoing regional chemotherapy treatment involving the 15-min inflation and subsequent deflation of an intraaortic balloon. RESULTS: The hemodynamic changes observed were similar to those seen during aortic clamping and declamping in patients undergoing vascular surgery. Plasma ANP levels (median+/-SD) measured 1 min after inflation (146+/-117 pg/mL) and 1 min after deflation (168+/-189 pg/mL) of the aortic balloon were significantly higher than baseline values (83+/-55 pg/mL), with a mean increase, respectively, of 92% and 97% (95% confidence intervals [CI], 50 to 147% and 53 to 152%). Plasma ANP levels were still elevated 30 min after deflation (121+/-94 pg/mL), a 56% increase (95% CI, 21 to 100%), although the hemodynamic parameters had already returned to their baseline levels. There was no evidence that the hemodynamic variables were associated with changes in plasma ANP levels (all p values > 0.30). In addition, there was no evidence of an association between plasma ANP and plasma norepinephrine levels at any of the four individual sampling points (p > 0.17). Thirty minutes after deflation, however, norepinephrine levels were higher than baseline values. CONCLUSIONS: The changes in plasma ANP levels after aortic occlusion and reinstitution of blood flow may be dependent on parameters other than atrial stretch and pressure.

Abdominal Neoplasms↗
PubMed1998

[Massive pulmonary embolism--summary of experiences with 13 patients].

Pulmonary embolism is a common event in hospitalized patients. In some cases it presents with hemodynamic collapse, indicating massive obliteration of the pulmonary vasculature and has a very grim prognosis; 2/3 of such patients die within 2 hours of onset of symptoms. We describe our experience in 13 patients with massive pulmonary embolism. An aggressive diagnostic and therapeutic approach, utilizing sophisticated imaging techniques, thrombolytic therapy and surgery, led to the survival of 8 of the patients. Our experience supports an aggressive approach in these seriously ill patients.

Adult↗
PubMed1998

[Propofol anesthesia for craniotomy in patients who are awake].

During craniotomy, the patient's cooperation is needed during procedures in which continuous neurological examination and mapping of crucial regions close to the area to be resected area are required. We report our experience in 9 patients who underwent such procedures under intravenous propofol as the main sedating agent. This short-acting hypnotic was administered prior to and during the painful stages of the procedure. Patients were fully asleep when the skull was opened and the dural flap raised or excised. During the rest of the operation patients were lightly sedated but remained responsive and cooperative. This enabled precise intra-operative mapping of the brain and surgery-related neurological deficits were avoided. Respiratory depression or hemodynamic compromise were not encountered. All patients were comfortable during the operation and there were no additional neurological deficits after operation. We believe that propofol should be the main sedating agent used for these procedures.

Aged↗
PubMed1998

Hemodynamic changes during a new procedure for regional chemotherapy involving occlusion of the thoracic aorta and inferior vena cava.

STUDY OBJECTIVE: To describe the hemodynamic consequences of a regional chemotherapy procedure involving occlusion of the thoracic aorta and inferior vena cava (IVC) by intraluminal balloons. DESIGN: Prospective study. SETTING: Operating rooms of an academic hospital. PATIENTS: 10 patients with inoperable intraabdominal malignancy. INTERVENTIONS: After the induction of general anesthesia and the insertion of a pulmonary artery catheter the patients underwent the regional chemotherapy procedure. MEASUREMENTS AND MAIN RESULTS: Occlusion of the thoracic aorta induced an increase in blood pressure (BP) and systemic vascular resistance (SVR) (41% +/- 8% and 80% +/- 15% from baseline, respectively), and a 30% +/- 7% decrease in cardiac output (CO). After aortic balloon deflation at the end of the procedure, we observed a decrease in BP to baseline values, decrease in SVR (to 62% +/- 12% below baseline), and increase in CO (to 80% +/- 15% above baseline). Those changes resemble those described during vascular surgery. Isolated occlusion of the IVC before aortic occlusion caused hemodynamic deterioration in only three of 10 patients, suggesting incomplete obstruction or collateral blood flow in others. Occluding the IVC while the aorta was occluded, caused minimal hemodynamic changes. CONCLUSIONS: Independent inflation of the IVC balloon should not be performed routinely because of possible unpredicted hemodynamic instability. Inferior vena cava occlusion should always be performed after complete aortic occlusion, because it is then that it produces negligible hemodynamic consequences. It is possible that a better assessment of IVC occlusion after balloon inflation needs to be done by contrast injection to prevent a possible leak of chemotherapeutic drugs.

Abdominal Neoplasms↗
PubMed1998

Malignant hyperthermia.

Malignant hyperthermia is a rare autosomal dominant trait that predisposes affected individuals to great danger when exposed to certain anaesthetic triggering agents (such as potent volatile anaesthetics and succinylcholine). A sudden hypermetabolic reaction in skeletal muscle leading to hyperthermia and massive rhabdomyolysis can occur. The ultimate treatment is dantrolene sodium a nonspecific muscle relaxant. Certain precautions should be taken before anaesthesia of patients known to be susceptible to malignant hyperthermia. These include the prohibition of the use of triggering agents, monitoring of central body temperature and expired CO2, and immediate availability of dantrolene. In addition, careful cleansing of the anaesthesia machine of vapours of halogenated agents is recommended. If these measures are taken, the chances of an MH episode are greatly reduced. When malignant hyperthermia-does occur in the operating room, prompt recognition and treatment usually prevent a potentially fatal outcome. The most reliable test to establish susceptibility to malignant hyperthermia is currently the in vitro caffeine-halothane contracture test. It is hoped that in the future a genetic test will be available.

Anesthesia↗
PubMed1997

[Effect of chlorocresol vs caffeine on muscle contracture in malignant hyperthermia susceptible patients].

The phenotype of susceptibility to malignant hyperthermia (MHS); can only be detected reliably by the in vitro caffeine-halothane contracture test (CHCT). Enhanced sensitivity of the calcium-induced calcium release mechanism is responsible for the exaggerated contracture response of skeletal muscle fibers from MHS patients to halothane and caffeine. Chlorocresol was demonstrated to be a potent activator of Ca++ release from skeletal muscle sarcoplasmic reticulum. This effect is probably mediated through action on a ryanodine sensitive Ca++ release channel known to be more sensitive in MH. We studied the effect of chlorocresol on the mechanical contracture response of skeletal muscle from patients presenting for the in vitro CHCT. Chlorocresol induces contracture response in a concentration 1/200 of that of caffeine in muscle strips from MH patients. By adding chlorocresol to the protocol of the CHCT, there is clearer discrimination between the responses of MH patients and normal subjects can be achieved.

Adolescent↗
PubMed1997

New monitors of intravascular volume: a comparison of arterial pressure waveform analysis and the intrathoracic blood volume.

OBJECTIVE: Two new monitoring techniques, the analysis of arterial pressure waveform during mechanical ventilation and the determination of intrathoracic blood volume, were evaluated for preload assessment in a model of graded hemorrhage. DESIGN: 8 anesthetized dogs bled of 10, 20, and 30% of their blood volume, then retransfused and volume loaded with plasma expander. Central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), cardiac output, parameters of the arterial pressure waveform analysis [systolic pressure variation (SPV) and delta down (dDOWN)], and intrathoracic blood volume (ITBV) were measured at baseline and after each stage of hemorrhage and volume expansion. RESULTS: The stroke volume index decreased significantly from 1.3 +/- 0.4 ml/kg at baseline to 0.7 +/- 0.2 ml/kg at 30% hemorrhage and then increased after retransfusion and volume loading. The changes in the filling pressures during the various stages of hemorrhage were in the range of 1-2 mmHg. CVP decreased from 5.5 +/- 0.9 to 3.1 +/- 1.7 mmHg and PCWP from 8.0 +/- 0.8 to 5.1 +/- 1.2 mmHg at 30% hemorrhage. Both filling pressures responded significantly to retransfusion; PCWP also changed in response to a volume load. SPV and dDOWN (expressed as percent of the systolic blood pressure during a short apnea) increased significantly from 6.7 +/- 1.7 and 5.6 +/- 3.2%, respectively, at baseline, to 9.7 +/- 2.6 and 8.1 +/- 2.9% after 10% blood loss and to 13.1 +/- 3.9 and 11.1 +/- 3.8% after 30% hemorrhage. ITBV decreased significantly from 29.7 +/- 4.5 to 26.8 +/- 5.3 ml/kg after 10% blood loss and to 23.1 +/- 3.0 ml/kg after 30% hemorrhage. ITBV, SPV, and dDOWN responded significantly to retransfusion and volume load. Significant correlations were found between the degree of volume change and dDOWN (r = 0.93), SPV (r = 0.96), ITBV (r = 0.95), CVP (r = 0.82), and PCWP (r = 0.90). CONCLUSIONS: The parameters of arterial pressure waveform analysis (SPV and dDOWN) and ITBV were sensitive estimates of cardiac preload during the early stages of hemorrhage. Measurement of SPV and dDOWN, being both sensitive and relatively noninvasive, has advantages over other methods of preload assessment but is limited to patients on controlled mechanical ventilation. ITBV, which supplies quantitative information about cardiac preload, is more invasive but can also be used in patients who are breathing spontaneously or who are on partial ventilatory support.

Analysis of Variance↗
PubMed1997

Malignant hyperthermia susceptibility: anaesthetic implications and risk stratification.

Malignant hyperthermia (MH) is a rare autosomal dominant trait that predisposes individuals to great danger when exposed to certain anaesthetic triggering agents, such as potent volatile anaesthetics and succinylcholine. Sudden hypermetabolic reaction occurs in skeletal muscle, leading to hyperthermia and massive rhabdomyolysis. Precautions must be taken before the anaesthesia of MH-susceptible patients. No triggering agents should be administered, central body temperature and ETCO2 should be carefully monitored, and dantrolene must be immediately available. In addition, the anaesthesia machine should be carefully washed to remove traces of halogenated agents, and the use of fresh disposable anaesthetic circuits is recommended. Early diagnosis of the syndrome by alert, informed anaesthesiologists, and the immediate administration of dantrolene and other supportive measures, has reduced mortality. Patients with MH susceptibility should be instructed to alert the anaesthesiologist about their condition whenever anaesthesia is needed. Although people diagnosed with MH susceptibility should not change their lifestyle in general, military service is limited.

Adolescent↗
PubMed1997

[Hemato-oncology patients in acute respiratory failure in the ICU].

Hemato-oncology patients needing mechanical ventilation for acute respiratory failure (ARF) have an extremely poor prognosis, with a mortality of more than 90%. Over an 18 month-period 17 such patients were admitted to our ICU. Diagnoses included leukemia (11 cases), lymphoma (1), and status post bone marrow transplantation for leukemia, lymphoma or breast cancer (5). Of 8 whose ARF was associated with septic complications due to neutropenia following chemotherapy, 6 survived. Of 9 who developed ARF due to toxic damage to vital organs following high-dose chemotherapy, 2 survived. Those who develop ARF during chemotherapy are expected to have an increase in granulocyte count within days, and have a surprisingly good prognosis. They should be admitted to the ICU and treated aggressively. Those who develop sepsis due their primary disease and whose general condition contraindicates chemotherapy, have an extremely grave prognosis and admission to the ICU may not be warranted.

Adult↗