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Biomedical subjects

M L Cheatham

Publications and source records attributed to M L Cheatham.

At least 19 recordsLinked to original sources
PubMed2000

Abdominal perfusion pressure: a superior parameter in the assessment of intra-abdominal hypertension.

OBJECTIVE: To assess the clinical utility of abdominal perfusion pressure (mean arterial pressure minus intra-abdominal pressure) as both a resuscitative endpoint and predictor of survival in patients with intra-abdominal hypertension. METHODS: 144 surgical patients treated for intra-abdominal hypertension between May 1997 and June 1999 were retrospectively reviewed. Multivariate logistic regression and receiver operating characteristic curve analysis of common physiologic variables and resuscitation endpoints were performed to determine the decision thresholds for each variable that predict patient survival. RESULTS: Abdominal perfusion pressure was statistically superior to both mean arterial pressure and intravesicular pressure in predicting patient survival from intra-abdominal hypertension and abdominal compartment syndrome. Multiple regression analysis demonstrated that abdominal perfusion pressure was also superior to other common resuscitation endpoints, including arterial pH, base deficit, arterial lactate, and hourly urinary output. CONCLUSION: Abdominal perfusion pressure appears to be a clinically useful resuscitation endpoint and predictor of patient survival during treatment for intra-abdominal hypertension and abdominal compartment syndrome.

Abdominal Injuries↗
PubMed2000

A structured curriculum for improved resident education in statistics.

Many resident physicians do not receive sufficient education in statistical theory and study design to allow them to effectively interpret and apply the medical literature to patient care. A survey of 62 surgical residency programs identified that only 33 per cent include formal statistics teaching in their curricula. A structured curriculum was formulated to introduce surgical residents to basic statistical theory, common statistical tests, and study design. Lectures were integrated into an existing monthly journal club in which manuscripts reviewed were used to illustrate the statistical concepts taught. Knowledge improvement was determined using a multiple choice test given before and after completion of the curriculum. Mean test scores increased significantly as a result of the curriculum (P < 0.004). Formal statistics education using a structured curriculum significantly improves resident physician knowledge of statistical theory and study design. Such teaching can be easily integrated into a residency program's existing curriculum.

Curriculum↗
PubMed2000

An unusual case of corneal perforation secondary to Pseudomonas keratitis complicating a patient's surgical/trauma intensive care unit stay.

We report a case of corneal perforation secondary to bacterial keratitis caused by Pseudomonas aeruginosa in a trauma patient in our intensive care unit. A 43-year-old man was involved in a motorcycle crash and suffered multiple injuries necessitating a prolonged intensive care unit (ICU) stay. Subsequently P. aeruginosa was cultured from his sputum, blood, and open abdomen. He developed a bacterial keratitis in his right eye, which also grew P. aeruginosa. This infection rapidly progressed to corneal perforation requiring a Gunderson conjunctival flap and lateral tarsorrhaphy in addition to aggressive antibiotic treatment. At the time of discharge from the hospital the patient had the return of vision to light only in his right eye. Corneal perforation is an unusual event in the ICU. Prevention or early detection of bacterial keratitis with aggressive antibiotic treatment is needed to prevent such complications. Pseudomonas is one of the more virulent organisms that can infect the cornea and early identification is paramount for a good outcome. Management of this complicated case is discussed and the limited amount of literature on nosocomial bacterial keratitis in the ICU is reviewed.

Adult↗
PubMed1999

Preload assessment in patients with an open abdomen.

BACKGROUND: Intra-abdominal hypertension and abdominal compartment syndrome cause significant morbidity and mortality in surgical and trauma patients. Maintenance of intravascular preload and use of open abdomen techniques are essential. The accuracy of pulmonary artery occlusion pressure (PAOP) and central venous pressure (CVP) in patients with intra-abdominal hypertension has been questioned. METHODS: Twenty surgical and trauma patients with intra-abdominal hypertension requiring open abdominal decompression were monitored using volumetric thermodilution pulmonary artery catheters. Hemodynamic, oxygenation, inspiratory, and intravesicular pressure measurements were collected prospectively. PAOP, CVP, and right ventricular end-diastolic volume index (RVEDVI) were compared as estimates of preload status. RESULTS: Multiple regression analysis demonstrated that cardiac index correlated significantly better with RVEDVI (r = 0.69) than with PAOP (r = -0.27) or CVP (r = -0.28) during resuscitation after open abdominal decompression (p < 0.0001). CONCLUSION: RVEDVI is superior to PAOP and CVP as an estimate of preload status in patients with an open abdomen.

Adolescent↗
PubMed1999

The underestimated impact of personal watercraft injuries.

The popularity of personal watercraft is steadily increasing, as are injuries related to their use. Many of these injuries are not reported to law enforcement agencies, and available personal watercraft injury statistics are suspected to be inaccurate. All personal watercraft-related injuries treated within a four-hospital system (including the regional Level I trauma center) between January 1993 and December 1997 were retrospectively identified. Patient demographics, accident mechanism, injuries sustained, tourist status, outcome, and economic data were collected and compared with available government statistics for the same time period. Sixty-eight consecutive patients injured during personal watercraft use were identified. Of these, 78 per cent were treated and released, whereas 22 per cent required inpatient management. Fractures and soft tissue injuries were the most common injuries sustained. Ninety-seven per cent of patients were discharged home. There was one fatality. Comparison with state and federal statistics identified that personal watercraft injuries are significantly underreported and have an estimated yearly economic impact of more than $235 million. Personal watercraft injuries represent an increasing source of watersport-related trauma. Government statistics on personal watercraft injuries do not accurately reflect the true incidence and economic impact of such trauma. Mandatory educational programs and increased legislation to improve personal watercraft safety should be promoted.

Accidents↗
PubMed1999

Life-threatening nail gun injuries.

The use of pneumatic and explosive cartridge-activated nail guns is common in the construction industry. The ease and speed of nailing these tools afford enhance productivity at the cost of increased potential for traumatic injury. Although extremity injuries are most common, life-threatening injuries to the head, neck, chest, or abdomen and pelvis may occur. During a 20-month period, eight potentially life-threatening nail gun injuries were admitted to a Level I trauma center, including injuries to the brain, eye, neck, heart, lung, and femoral artery. Mechanism of injury included nail ricochet, nail gun misuse due to inadequate training, and successful suicide. Nail guns have significant potential for causing severe debilitating injury and death. These findings indicate a need for improved safety features and user education. The various types of nail guns, their ballistic potential, and techniques for operative management are discussed.

Accidents, Occupational↗
PubMed1999

Ingested endotracheal tube in an adult following intubation attempt for head injury.

General surgeons are often consulted for assistance in the management of ingested foreign bodies. Deglutition of an endotracheal tube is an unusual complication of airway management. In these cases, the artificial airway is "lost" when it becomes lodged deep into the esophagus. Endoscopic extraction has been described as therapeutic. We report a case in which prehospital endotracheal intubation attempt for the management of closed head injury resulted in a swallowed endotracheal tube. The tube remained undetected until radiographs were performed for a second unrelated traumatic event 2 years later. Endoscopic extraction was unsuccessful, due to rigidity of the tube. Surgical extraction via gastrotomy was uneventful. Surgeons involved in trauma and other emergency settings should be aware of this complication and options in management.

Adult↗
PubMed1999

Air travel following traumatic pneumothorax: when is it safe?

The safety of air travel for patients sustaining a recent traumatic pneumothorax has long been a subject of debate. The Aerospace Medicine Association has suggested that patients should be able to fly 2 to 3 weeks after radiographic resolution of their pneumothorax. To validate these recommendations, a prospective study was performed. Twelve consecutive patients with recent traumatic pneumothorax expressing a desire to travel by commercial airline were evaluated. Ten patients waited at least 14 days after radiographic resolution of their pneumothorax before air travel (mean, 17.5+/-4.9 days), and all were asymptomatic in-flight. One of two patients who flew earlier than 14 days developed respiratory distress in-flight, with symptoms suggestive of a recurrent pneumothorax. We conclude that commercial air travel appears to be safe 14 days following radiographic resolution of a traumatic pneumothorax.

Adult↗
PubMed1998

Peripherally inserted central catheters revisited.

BACKGROUND: This study compares central venous catheters (CVC) and peripherally inserted central catheters (PICC) for indications for insertion, complications, and economic impact. METHODS: A retrospective review of 838 (283 CVC, 555 PICC) consecutively placed venous catheters reflected 49,365 CVC and 11,814 PICC days. RESULTS: There were 57 (20%) complications in the CVC group, 197 (35%) complications in the PICC group. PICC were associated with a statistically significant increase in the incidence of catheter malfunction (P = 0.0005), arm vein phlebitis (P = 0.0004), and overall complications (P = 0.00001). A higher complication rate was noted in PICC inserted for chemotherapy (P = 0.00001) and parenteral hyperalimentation administration (P = 0.04). Charges for inpatient insertion of PICC and CVC were $500 and $2,500, respectively. CONCLUSIONS: PICC have a significantly higher complication rate than CVC. PICC provide cost-effective central access of 2 to 3 weeks' duration, reserving operatively placed CVC for longer access requirements.

Adult↗
PubMed1998

Right ventricular end-diastolic volume index as a predictor of preload status in patients on positive end-expiratory pressure.

OBJECTIVE: To evaluate the clinical utility of right ventricular end-diastolic volume index (RVEDVI) and pulmonary artery occlusion pressure (PAOP) as measures of preload status in patients with acute respiratory failure receiving treatment with positive end-expiratory pressure. DESIGN: Prospective, cohort study. SETTING: Surgical intensive care unit in a Level I trauma center/university hospital. PATIENTS: Sixty-four critically ill surgical patients with acute respiratory failure. INTERVENTIONS: All patients were treated for acute respiratory failure with titrated levels of positive end-expiratory pressure (PEEP) with the goal of increasing arterial oxygen saturation to > or =0.92, reducing FIO2 to <0.5, and reducing intrapulmonary shunt to < or =0.2. Serial determinations of RVEDVI, PAOP, and cardiac index (CI) were recorded. MEASUREMENTS AND MAIN RESULTS: Two hundred-fifty sets of hemodynamic variables were measured in 64 patients. The level of PEEP ranged from 5 to 50 cm H2O (mean 12+/-9 [SD] cm H2O). At all levels of PEEP, CI correlated significantly better with RVEDVI than with PAOP. At levels of PEEP > or =15 cm H2O, CI was inversely correlated with PAOP, but remained positively correlated with RVEDVI. CONCLUSIONS: CI correlates significantly better with RVEDVI than PAOP at all levels of PEEP up to 50 cm H2O. RVEDVI is a more reliable predictor of volume depletion and preload recruitable increases in CI, especially in patients receiving higher levels of PEEP where PAOP is difficult to interpret.

Acute Disease↗
PubMed1998

Evaluation of acute mental status change in the nonhead injured trauma patient.

Acute mental status change in the first 24 hours after trauma is uncommon in nonhead injured patients who initially present with a normal sensorium. Although arterial hypoxemia is the classic etiology for such a mental status change, three less common etiologies should always be considered: cerebral fat embolism, blunt carotid artery injury, and vertebrobasilar artery thrombosis. Prompt diagnosis and appropriate treatment can significantly improve patient morbidity and mortality. Three nonhead injured trauma patients are described illustrating cerebral fat embolism, blunt carotid artery injury, and vertebrobasilar artery thrombosis as causes of acute mental status change. Each patient initially presented with a clear sensorium, but subsequently developed neurological deficits within 24 hours after admission. All had a normal admission CT scan of the head. MRI or conventional arteriography was diagnostic in each case. Any patient who is initially lucid and subsequently develops a neurological deficit, or a patient whose neurological status does not correlate with brain CT findings should undergo immediate evaluation for possible cerebral fat embolism or cervical vessel injury. An algorithm for management of nonhead injured trauma patients with acute mental status deterioration is presented.

Accidents, Traffic↗
PubMed1995

A meta-analysis of selective versus routine nasogastric decompression after elective laparotomy.

OBJECTIVE: A meta-analysis of all published clinical trials comparing selective versus routine nasogastric decompression was performed in an attempt to evaluate the need for nasogastric decompression after elective laparotomy. BACKGROUND: Many studies have suggested that routine nasogastric decompression is unnecessary after elective laparotomy and may be associated with an increased incidence of complications. Despite these reports, many surgeons continue to practice routine nasogastric decompression, believing that its use significantly decreases the risk of postoperative nausea, vomiting, aspiration, wound dehiscence, and anastomotic leak. METHODS: A comprehensive search of the English language medical literature was performed to identify all published clinical trials evaluating nasogastric decompression. Twenty-six trials (3964 patients) met inclusion criteria. The outcome data extracted from each trial were subsequently "pooled" and analyzed for significant differences using the Mantel-Haenszel estimation of combined relative risk. RESULTS: Fever, atelectasis, and pneumonia were significantly less common and days to first oral intake were significantly fewer in patients managed without nasogastric tubes. Meta-analysis based on study quality revealed significantly fewer pulmonary complications, but significantly greater abdominal distension and vomiting in patients managed without nasogastric tubes. Routine nasogastric decompression did not decrease the incidence of any other complication. CONCLUSIONS: Although patients may develop abdominal distension or vomiting without a nasogastric tube, this is not associated with an increase in complications or length of stay. For every patient requiring insertion of a nasogastric tube in the postoperative period, at least 20 patients will not require nasogastric decompression. Routine nasogastric decompression is not supported by meta-analysis of the literature.

Elective Surgical Procedures↗
PubMed1994

Gastric tonometry supplements information provided by systemic indicators of oxygen transport.

HYPOTHESIS: Assessment of splanchnic perfusion by gastric intramucosal pH (pHi) adds to the information provided by systemic indicators of oxygen transport. SETTING: University Hospital level I trauma center. DESIGN: Prospective study in 20 critically ill trauma patients comparing pHi with base deficit, lactate, oxygen delivery, and oxygen consumption (indexed to body surface area), mixed venous oxygen saturation (Svo2), oxygen utilization coefficient, and arterial pH. All measurements were obtained at admission, 1, 2, 4, 8, 16, and 24 hours, or at death. MAIN OUTCOME MEASURES: Correlation of pHi with the measured systemic variables, prediction of organ dysfunction, development of multiple organ dysfunction syndrome, and mortality. RESULTS: There was a poor correlation between pHi and the systemic hemodynamic and oxygen transport variables. Patients with a low pHi (< 7.32) on admission who did not correct within the initial 24 hours had a higher mortality (50% vs. 0.0%, p = 0.03) and incidence of organ dysfunction (2.6 organs/patient vs. 0.62 organs/patient, p = 0.02) than those who did. Using logistic regression analysis, only pHi, base deficit, and Svo2 were significantly associated with mortality during the study period. At 24 hours, only pHi was different between patients who developed multiple organ dysfunction syndrome and those who did not. There was a threshold value for pHi (7.10) which identified those patients who would go on to develop multiple organ dysfunction syndrome. CONCLUSIONS: Uncorrected splanchnic malperfusion is associated with a higher incidence of organ dysfunction and mortality. Gastric tonometry supplements information provided by systemic indicators of oxygen transport during resuscitation of critically ill trauma patients.

Acid-Base Equilibrium↗
PubMed1993

Drilling the posterior wall of the petrous pyramid: a microneurosurgical anatomical study.

Posterior approaches to the petroclival area requiring extensive drilling of the posterior pyramidal wall have been described in the last 10 years. If hearing is to be preserved, damage to the inner-ear structures must be avoided; however, the fine points of this pyramidal drilling technique have never been reported in detail. A microneurosurgical anatomical study was undertaken in 15 cadavers to determine the relationships between bone landmarks and labyrinthine structures that could be used to give some practical drilling guidelines. Drilling of the posterior pyramidal wall is facilitated on identification of the intersection of the petrous ridge with the most anterior portion of the bone ledge covering the sigmoid sinus (petrosigmoid intersection), the bony operculum of the endolymphatic sac, and the petrous ridge. Drilling may proceed rather safely at a minimum depth of 2.5 mm in an area 0.9 cm anterior and 1 cm inferior to the petrosigmoid intersection and petrous ridge, respectively. From there, identification of the vestibular aqueduct, genu, and horizontal portion is necessary to safely open the posterior wall of the internal auditory canal. The vestibular aqueduct represents the lateral and superior limits of drilling. The bone between these areas may then be safely drilled to a depth of at least 2.5 mm. A microneurosurgical dissection of the posterior pyramidal wall conducted in cadaveric material according to these guidelines did not violate any inner-ear structures.

Ear, Middle↗
PubMed1993

The mandibular swing-transcervical approach to the skull base: anatomical study. Technical note.

This report describes in a stepwise fashion the surgical anatomy of an approach to the midline and lateral compartments of the skull base (clivus, infralabyrinthine/infratemporal regions). The salient features of this procedure are represented by a mandibulotomy and by detachment of the pharynx from the skull base through a combined oral and cervical approach. There is full neurovascular control of the internal carotid artery and lower cranial nerves with the possibility of complete exposure of the intrapetrous and intracavernous segments of the internal carotid artery on the side of the exposure. This approach, which may be regarded as an expansion of the original work of Krespi, should be considered when dealing aggressively with extensive skull-base lesions invading the midline and lateral compartments of the skull base.

Cadaver↗