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Biomedical subjects

M J Wall

Publications and source records attributed to M J Wall.

At least 37 records · Page 2Linked to original sources
PubMed1998

Remote clinical assessment for acute trauma: an initial experience.

Optimal care of the injured patient requires an organized approach, dedicated resources and clinical expertise. Victims of major trauma, however, frequently present to rural and suburban hospitals regardless of whether a dedicated trauma system in place. Immediate consultation by a trauma expert could potentially expedite effective evaluation and management of trauma victims, reducing the occurrence of unnecessary transport and leading to efficient stabilization and transport when needed. Remote assessment of trauma patients must be assesses for feasibility, safety and efficacy before widespread implementation. This project represents the initial steps towards the development of a functional telemedicine system for trauma care.

Acute Disease↗
PubMed1997

Damage control for thoracic injuries.

Some of the earliest damage control techniques were applied to the chest during emergency center thoracotomy. It provided a paradigm that was adapted to other areas. Damage control of chest injuries has a different philosophy than that of abdominal injuries. Damage control in the abdomen primarily consists of multiple staged operations with abbreviated closures. Damage control in the chest consists of different technical maneuvers to use quicker and technically less demanding operations to accomplish the same goal. The philosophy of doing only enough to restore a survivable physiology is still a common theme. The following are the major principles of damage control for thoracic injuries: 1. Emergency center thoracotomy is a damage control prototype. 2. Anterolateral thoracotomy is the empiric incision of choice in the patient in extremis. 3. Nonanatomically stapled lung resections, pulmonary tractotomy, and en masse lobectomy/pneumonectomy are pulmonary damage control procedures. 4. The unique physiology of the chest may require en masse closure of muscles or patch closure of the wound. 5. Cardiopulmonary physiology can be affected by packing. Packing thus has a limited role in thoracic damage control. 6. Prosthetic grafts, intravascular shunts, and ligation are common thoracic vascular damage control techniques. 7. With new technology, an increased role for cardiopulmonary bypass and cardiac assistance may develop. 8. New technology must not overly complicate a procedure if it is to be a valuable damage control adjunct.

Arteries↗
PubMed1997

Gastric rupture with tension pneumoperitoneum: a complication of difficult endotracheal intubation.

Gastric rupture is a rare complication of difficult airway management. In cases of vigorous mouth-to-mouth ventilation, bag-valve-mask ventilation, or esophageal intubation, gastric rupture and massive intraperitoneal free air may cause tension pneumoperitoneum. Hemodynamic instability necessitates immediate intervention, including needle decompression of the peritoneum followed by surgical exploration. We recently encountered two cases of gastric rupture with tension pneumoperitoneum that occurred after difficult endotracheal intubation. This report describes the presentation, treatment, and prevention of this entity.

Aged↗
PubMed1997

Acute management of complex cardiac injuries.

BACKGROUND: Injury to the heart has been studied extensively. However, a small group of patients with injuries to the coronary arteries or intracardiac structures may require a different operative approach. METHODS: Retrospective review of a cardiovascular injury database. RESULTS: Over a 20-year period, 711 cardiac injuries were treated. The mean age of the victims was 31.1 (90% men). Causes were primarily stab wounds (54%) and gunshot wounds (42%). Cardiac chambers injured included the right ventricle (40%), left ventricle (40%), right atrium (24%), and left atrium (3%). The overall mortality was 47%. Sixty complex injuries occurred. Of 21 left anterior descending coronary artery injuries (76.2% mortality), two patients presented with sufficient signs of life to warrant emergent coronary artery bypass (mortality 50%). There were seven circumflex/obtuse marginal coronary artery injuries, all treated with ligation (mortality 71.4%). Eight right/posterior descending coronary artery injuries (mortality 62.5%) were seen, and all but one were treated with ligation. The one patient not treated with ligation underwent coronary bypass and died. Delayed mitral valve replacement was performed for two valvular injuries (mitral). There were a total of 14 intracardiac fistulas (mortality 35.7%). All six of the surviving patients with ventricular septal defect required reoperation. CONCLUSION: The mortality for complex injuries (coronary, septal, valvular) was 53%. This group was a specific population that self-selected by surviving to operation. Acute operations for complex injuries (beyond cardiorrhaphy) were primarily heroic life-saving efforts. Reoperation for cardiac injuries was most common for septal or valvular injuries. Only 2% of all survivors required reoperation to correct a residual defect.

Acute Disease↗
PubMed1997

Development of action potential-dependent and independent spontaneous GABAA receptor-mediated currents in granule cells of postnatal rat cerebellum.

The postnatal development of spontaneous GABAergic transmission between cerebellar Golgi cells and granule cells was investigated with voltage-clamp recording from rat cerebellar slices, in symmetrical Cl- conditions. Between postnatal days 7 and 14 (P7-14), bicuculline- and TTX (tetrodotoxin)-sensitive spontaneous inhibitory postsynaptic currents (sIPSCs), occurred at high frequency in 56% of granule cells. Between P10 and P14, sIPSCs were superimposed on a tonic current of -12 +/- 1.8 pA at -70 mV, that was accompanied by noise with a variance of 17 +/- 3 pA2. Both the current and noise were inhibited by bicuculline. TTX blocked the bicuculline-sensitive current and noise by approximately 60%. Between P18 and P25, sIPSCs were less frequent; all cells showed tonic, bicuculline-sensitive currents, but these were partially inhibited by TTX (approximately 35%). Between P40 and P53, sIPSCs were rare; tonic, bicuculline-sensitive currents and noise were greater in amplitude, with mean values of -17 pA and 22 pA2 at -70 mV, they were present in all cells but they were not inhibited by TTX. Glycine receptor channels that were expressed in immature, but not adult cells, did not mediate spontaneous currents. Our results indicate that spontaneous transmission onto cerebellar granule cells in immature animals consists primarily of action potential-dependent, phasic release of vesicular GABA. This generates GABAA receptor-mediated sIPSCs. The effects of GABA transporter blockers suggest that it also produces the TTX-sensitive current-noise, as GABA spills out of synapses to activate extrasynaptic receptors or receptors in neighbouring synapses. In older animals, action potential-independent release of transmitter is predominant and results in tonic activation of GABAA receptors. This does not appear to be spontaneous vesicular release of GABA. Neither does it appear to be reversed uptake of GABA, although further work is required to rule out these possibilities.

Action Potentials↗
PubMed1997

Newer diagnostic measures and emergency management.

Evolving technology provides new diagnostic and emergency management options for the surgeon caring for patients with thoracic trauma. Abdominal ultrasound performed by surgeons in the emergency department makes pericardiocentesis and subxyphoid pericardiotomy obsolete. Transesophageal echocardiography supplements aortography in the diagnosis of thoracic aortic injury. New terminologies replace the overused term myocardial contusion. Pulmonary tractotomy is an innovative approach to through-and-through pulmonary penetrating injuries. Centrifugal pumps add new options to thoracic great-vessel injury management. Endovascular stented grafts will be added to the armentarium of the thoracic surgeon for injured vessels.

Diagnostic Imaging↗
PubMed1997

Prolonged abdominal packing for trauma is associated with increased morbidity and mortality.

Abdominal packing and planned reoperation is a lifesaving technique for temporary control of hemorrhage in severely injured patients. Morbidity and mortality in this group of patients, however, remain significant. It is unclear whether the duration of packing impacts upon outcome. The purpose of this study is to evaluate the abscess, sepsis, and mortality rates associated with duration of abdominal packing. The records of 35 patients treated with abdominal packing between July 1994 and December 1995 who survived to reoperation were retrospectively reviewed. Evaluation included age; sex; mechanism; injuries; Abdominal Trauma Index; duration of packing; survival; and presence of abscess, sepsis or other infections. Patients packed for a total of 72 hours or less had lower abscess, sepsis, and mortality rates than those packed for more than 72 hours. The differences in abscess rate and mortality were statistically significant (P < 0.05). The Abdominal Trauma Index and mechanism of injury were similar for the two groups. Based on these results, we conclude that although abdominal packing is a useful technique in the severely injured patient, it is associated with greater morbidity and mortality when the duration of packing exceeds 72 hours.

Abdominal Abscess↗
PubMed1996

The pathogenesis of Staphylococcus aureus in the trauma patient and potential future therapies.

BACKGROUND: Staphylococcus aureus is the most frequently isolated pathogen in the trauma patient and uses multiple virulent factors to cause infection. At the cellular level, infection begins with the prokaryotic bacterial cell manipulating the eukaryotic host cell through its virulent factors. Researching this cellular interaction by describing the mechanisms of actions of various virulent factors may lead to new preventive therapies which will make the trauma patient less susceptible to S aureus infections. METHODS: Surgical, medical, and microbial literature was reviewed to provide an update on S aureus pathogenesis. RESULTS: Novel future therapies, in addition to antibiotics, are being devised based on understanding the molecular nature of S aureus pathogenesis. CONCLUSION: The impact of S aureus on trauma will increase as S aureus develops more antibiotic resistance and as the trauma population becomes older and includes an increasing proportion of immunocompromised patients. To meet the challenge of increased virulence, trauma surgeons should be directly involved in the research of microbial pathogenesis.

Bacterial Adhesion↗
PubMed1996

Penetrating thoracic vascular injuries.

1. Known injuries to the ascending aorta and arch are exposed by median sternotomy. Known injuries to the descending thoracic aorta can be exposed through a posterolateral thoracotomy. These injuries are more commonly diagnosed through emergent exploration by means of anterolateral thoracotomies. 2. Preoperative arteriography is extremely useful in managing penetrating injuries to the thoracic outlet, as it allows the choice of appropriate incisions for exposure and control. 3. Innominate artery, right common carotid or subclavian artery, as well as left intrathoracic common carotid artery injuries are best managed via median sternotomy with appropriate extension. 4. Left subclavian arteries are managed with high left anterolateral thoracotomy for proximal control combined with supraclavicular incision. 5. Distal subclavian arteries are managed with proximal control by a supraclavicular incision and distal control by an infraclavicular incision. 6. The bypass principle is useful for managing innominate or left carotid artery injuries. Ligation with brachiocephalic bypass can be a simple solution to a complex problem. 7. Soft grafts, fine sutures, and minimal mobilization are the techniques of choice. 8. Adjuncts such as Fogarty balloon catheters, Foley catheters, autotransfusion, shunts, and pulmonary tractotomy can be useful in managing these injuries. 9. Documentation of the preoperative neurovascular status of the patient should be performed, as well as discussion with the patient and the family, if available, of the potential outcome with appropriate documentation in the chart. 10. Rehabilitation services should be involved as appropriate to care for these patients. 11. Ligation is always an option to save the patient's life.

Blood Vessel Prosthesis↗
PubMed1995

A slowly activating Ca(2+)-dependent K+ current that plays a role in termination of swimming in Xenopus embryos.

1. Acutely isolated Xenopus spinal neurons possess a slowly activating Ca(2+)-dependent outward current which was revealed either by removal of external Ca2+ or by the addition of the Ca2+ channel blocker, 150 microM Cd2+. 2. The Ca(2+)-sensitive current was very slow to activate and had a mean time constant of activation of 437 ms at 0 mV. The current also had very long tail currents which were blocked by Cd2+. The rate of decay of the slowest component of the Ca(2+)-dependent tail currents was insensitive to membrane potential suggesting that the relaxation of the Ca(2+)-dependent current may only be weakly voltage dependent. 3. The reversal potential of the Ca(2+)-sensitive tail currents depended on the concentration of external K+ in a manner predicted by the Nernst equation. Thus the Ca(2+)-sensitive current was carried by K+. 4. The toxin apamin (10 nM to 2 microM) selectively blocked the Ca(2+)-dependent K+ current without affecting voltage-gated K+ currents. This current may be analogous to a small-conductance Ca(2+)-dependent K+ (SK) current; however, unlike some SK currents, the Ca(2+)-dependent K+ current was also sensitive to 500 microM tetraethylammonium chloride (TEA). 5. Applications of 10 nM apamin to spinalized embryos did not perturb the motor pattern for swimming. However, the cycle periods over which the locomotor rhythm generator could generate appropriate motor activity were lengthened by about 10% and the mean duration of swimming episodes was increased by approximately 40%. 6. We therefore propose that the Ca(2+)-dependent K+ current plays an important role in the self-termination of motor activity.

Animals↗
PubMed1995

Predictors of amputation for popliteal artery injuries.

BACKGROUND: Popliteal artery injuries continue to result in limb loss. This study identifies risk factors that predict amputation. METHODS: Over a 5-year period, a retrospective chart review was conducted of 80 consecutive patients with 81 popliteal artery injuries. RESULTS: The overall amputation rate was 16.5%. Blunt trauma carried a higher rate of amputation (47%) than penetrating injuries (6.2%); P < 0.0001). Associated fractures had a higher amputation rate, regardless of mechanism (odds ratio +2.7, 95% confidence limits 1.2 to 6.2). Fasciotomy at the time of operation was associated with reduced amputation rate. CONCLUSIONS: Blunt injuries and associated fractures carry an increased risk for amputation. Compartmental pressures should be appropriately monitored postoperatively. Fasciotomy at the time of vascular repair may be considered even without evidence of compartment syndrome.

Adolescent↗
PubMed1995

Double jeopardy: thoracoabdominal injuries requiring surgical intervention in both chest and abdomen.

The critical decisions in patients with thoracoabdominal trauma are establishing the need to explore either or both cavities and determining appropriate sequencing. The causes and patterns of management difficulties were analyzed in 82 consecutive patients with penetrating thoracoabdominal injuries. Nine thoracotomies (11%) and 16 laparotomies (22%) were negative, with the major causes being misleading chest tube outputs, bullet trajectories, and abdominal tenderness. Inappropriate sequencing occurred in 19 patients (23%), and 15% required reoperation within 24 hours. Pitfalls and misjudgements in management of penetrating thoracoabdominal injuries occur in distinct patterns. The unreliability of chest tube output and abdominal examination must be kept in mind, and intraoperative clues of ongoing hemorrhage outside the operative field must be sought.

Abdominal Injuries↗
PubMed1994

Immediate versus delayed fluid resuscitation for hypotensive patients with penetrating torso injuries.

BACKGROUND: Fluid resuscitation may be detrimental when given before bleeding is controlled in patients with trauma. The purpose of this study was to determine the effects of delaying fluid resuscitation until the time of operative intervention in hypotensive patients with penetrating injuries to the torso. METHODS: We conducted a prospective trial comparing immediate and delayed fluid resuscitation in 598 adults with penetrating torso injuries who presented with a pre-hospital systolic blood pressure of < or = 90 mm Hg. The study setting was a city with a single centralized system of pre-hospital emergency care and a single receiving facility for patients with major trauma. Patients assigned to the immediate-resuscitation group received standard fluid resuscitation before they reached the hospital and in the trauma center, and those assigned to the delayed-resuscitation group received intravenous cannulation but no fluid resuscitation until they reached the operating room. RESULTS: Among the 289 patients who received delayed fluid resuscitation, 203 (70 percent) survived and were discharged from the hospital, as compared with 193 of the 309 patients (62 percent) who received immediate fluid resuscitation (P = 0.04). The mean estimated intraoperative blood loss was similar in the two groups. Among the 238 patients in the delayed-resuscitation group who survived to the postoperative period, 55 (23 percent) had one or more complications (adult respiratory distress syndrome, sepsis syndrome, acute renal failure, coagulopathy, wound infection, and pneumonia), as compared with 69 of the 227 patients (30 percent) in the immediate-resuscitation group (P = 0.08). The duration of hospitalization was shorter in the delayed-resuscitation group. CONCLUSIONS: For hypotensive patients with penetrating torso injuries, delay of aggressive fluid resuscitation until operative intervention improves the outcome.

Abdominal Injuries↗
PubMed1994

Transcervical gunshot injuries.

Gunshot injuries across the cervical midline are not addressed in existing trauma algorithms. A retrospective study of 41 patients with transcervical gunshot wounds was undertaken to delineate injury patterns and management principles. Thirty-four of the 41 patients (83%) sustained 52 injuries to major cervical structures. Vascular (22 injuries) and upper airway (13 injuries) structures were most commonly involved. This resulted in presentation with life-threatening problems in 16 patients (39%). The in-hospital mortality was 10%. In 30 of the 36 neck explorations (83%), the findings were positive for injuries to cervical structures. Sixteen bilateral explorations were performed; in each case, cervical injury was observed on at least one side of the neck. These results indicate that transcervical injuries are excellent markers of associated visceral injury. Therefore, a policy of mandatory neck exploration and a particularly "low threshold" for bilateral exploration are the key to managing these injuries.

Adolescent↗
PubMed1994

Delayed tension pneumopericardium after thoracotomy for penetrating chest trauma.

Tension pneumopericardium is a rare entity typically described in premature infants requiring positive-pressure ventilation. However, recent reports suggest an increase in its occurrence in adults. A case of delayed postoperative tension pneumopericardium in an adult patient is presented with a review of the history, pathophysiology, presentation, and treatment of this entity.

Adult↗
PubMed1994

Pulmonary tractotomy with selective vascular ligation for penetrating injuries to the lung.

BACKGROUND: The operative management of penetrating lung injuries includes oversewing of small lung lacerations (pneumonorrhaphy), wedge resection, or anatomic resection. There are penetrating injuries of the lung for which oversewing of entrance and exit wounds will predispose to intrapulmonary hematoma or pulmonary venous-systemic air emboli, yet for which formal resection would be time consuming. The technique of pulmonary tractotomy with selective vascular ligation was developed in parallel with hepatotomy for liver injuries. PATIENTS AND METHODS: Over the past 9 years, pulmonary tractotomy has been used 18 times in 16 patients at our institution. All patients were male. Their injuries were 12 gunshot and 4 stab wounds. RESULTS: There were three deaths unrelated to the tractotomy. Five surviving patients developed complications. CONCLUSION: Pulmonary tractotomy is a straight-forward procedure that controls deep hemorrhage from lung injuries and may obviate the need for formal resection.

Adult↗
PubMed1994

Causes and patterns of missed injuries in trauma.

Missed injuries have a bad reputation and are sometimes associated with serious morbidity for the patient and personal embarrassment for the surgeon. During a 10-year period, 123 missed injuries in 117 patients requiring re-operation were encountered in one trauma center. A retrospective review of causes and patterns was undertaken. The most common presentation was delayed hemorrhage (64 injuries). The colon, thoracic vasculature, chest wall arteries, and diaphragm were the most frequently involved sites. Forty-six injuries were overlooked during the diagnostic work-up, and 43 were missed during surgery. Technical problems with diagnosis and surgery accounted for 62% of missed injuries, whereas decision and judgment errors accounted for the rest. Further insight was provided by the classification of missed injuries into three types. Type I (20%) occurred outside the body area of clinical focus, whereas type II (69%) occurred within it. Type III (11%) resulted when instability of the patient necessitated interruption of the diagnostic work-up or exploration. Each type represents a different clinical pattern and dictates a specific preventive strategy.

Diagnostic Errors↗