Erik S. Shank

Decompression illness, iatrogenic gas embolism, and carbon monoxide poisoning: the role of hyperbaric oxygen therapy.

Decompression Illness and Iatrogenic Gas EmbolismHyperbaric oxygen therapy (HBOT) is the treatment of choice in medical emergencies in which gas bubbles released in the tissues lead to profound disturbances of physiological processes and tissue injury. There are two major pathways for gas bubble dis

Evaluation and management of decompression illness--an intensivist's perspective.

Decompression illness (DCI) is becoming more prevalent as more people engage in activities involving extreme pressure environments such as recreational scuba-diving. Rapid diagnosis and treatment offer these patients the best chance of survival with minimal sequelae. It is thus important that critical care physicians are able to evaluate and diagnose the signs and symptoms of DCI. The cornerstones of current treatment include the administration of hyperbaric oxygen and adjunctive therapies such as hydration and medications. However, managing patients in a hyperbaric environment does present additional challenges with respect to the particular demands of critical care medicine in an altered pressure environment. This article reviews the underlying pathophysiology, clinical presentation and therapeutic options available to treat DCI, from the intensivist’s perspective.

Acute and perioperative care of the burn-injured patient.

Care of burn-injured patients requires knowledge of the pathophysiologic changes affecting virtually all organs from the onset of injury until wounds are healed. Massive airway and/or lung edema can occur rapidly and unpredictably after burn and/or inhalation injury. Hemodynamics in the early phase of severe burn injury is characterized by a reduction in cardiac output and increased systemic and pulmonary vascular resistance. Approximately 2 to 5 days after major burn injury, a hyperdynamic and hypermetabolic state develops. Electrical burns result in morbidity much higher than expected based on burn size alone. Formulae for fluid resuscitation should serve only as guideline; fluids should be titrated to physiologic endpoints. Burn injury is associated basal and procedural pain requiring higher than normal opioid and sedative doses. Operating room concerns for the burn-injured patient include airway abnormalities, impaired lung function, vascular access, deceptively large and rapid blood loss, hypothermia, and altered pharmacology.

Continuous noninvasive cardiac output in children: is this the next generation of operating room monitors? Initial experience in 402 pediatric patients.

Electrical Cardiometry™ (EC) estimates cardiac parameters by measuring changes in thoracic electrical bioimpedance during the cardiac cycle. The ICON®, using four electrocardiogram electrodes (EKG), estimates the maximum rate of change of impedance to peak aortic blood acceleration (based on the premise that red blood cells change from random orientation during diastole (high impedance) to an aligned state during systole (low impedance)).

Age-dependency of sevoflurane-induced electroencephalogram dynamics in children

BACKGROUND General anaesthesia induces highly structured oscillations in the electroencephalogram (EEG) in adults, but the anaesthesia-induced EEG in paediatric patients is less understood. Neural circuits undergo structural and functional transformations during development that might be reflected in anaesthesia-induced EEG oscillations. We therefore investigated age-related changes in the EEG during sevoflurane general anaesthesia in paediatric patients. METHODS We analysed the EEG recorded during routine care of patients between 0 and 28 yr of age (n=54), using power spectral and coherence methods. The power spectrum quantifies the energy in the EEG at each frequency, while the coherence measures the frequency-dependent correlation or synchronization between EEG signals at different scalp locations. We characterized the EEG as a function of age and within 5 age groups: <1 yr old (n=4), 1-6 yr old (n=12), >6-14 yr old (n=14), >14-21 yr old (n=11), >21-28 yr old (n=13). RESULTS EEG power significantly increased from infancy through ∼6 yr, subsequently declining to a plateau at approximately 21 yr. Alpha (8-13 Hz) coherence, a prominent EEG feature associated with sevoflurane-induced unconsciousness in adults, is absent in patients <1 yr. CONCLUSIONS Sevoflurane-induced EEG dynamics in children vary significantly as a function of age. These age-related dynamics likely reflect ongoing development within brain circuits that are modulated by sevoflurane. These readily observed paediatric-specific EEG signatures could be used to improve brain state monitoring in children receiving general anaesthesia.

Der schwere Tauchunfall Pathophysiologie – Symptomatik – Therapie

ZusammenfassungDer schwere Tauchunfall ist ein potentiell lebensbedrohliches Ereignis, verursacht durch raschen Abfall des Umgebungsdrucks, der bei Tauchern und anderweitig überdruckexponierten Personen beobachtet wird.Hervorgerufen durch die Bildung freier Gasblasen im Blut und Geweben kann die Dekompressionserkrankung (DCI) abhängig vom Entstehungsmechanismus in Dekompressionskrankheit (DCS) und arterielle Gasembolie (AGE) unterschieden werden. Die DCS tritt nach längerem Aufenthalt im Überdruck und entsprechender Inertgasaufsättigung auf. Die AGE ist typischerweise die Folge eines pulmonalen Barotraumas, die Symptomatik ist bei zerebralem Befall der eines Schlaganfalls ähnlich.Wichtigste Sofortmaßnahmen sind die schnellstmögliche Gabe von Sauerstoff in höchstmöglicher Konzentration und die Volumentherapie. Wichtigste weiterführende Maßnahme ist die schnellstmögliche Rekompression in einer Therapiedruckkammer mit hyperbarem Sauerstoff. Der Transport der Verunfallten sollte möglichst erschütterungsfrei, bei Lufttransport ohne weitere Reduktion des Umgebungsdrucks erfolgen. Weitere, ergänzende Therapiemaßnahmen werden kontrovers diskutiert.AbstractDecompression injuries are potentially life-threatening incidents, generated by a rapid decline in ambient pressure. Although typically seen in divers, they may be observed in compressed air workers and others exposed to hyperbaric environments.Decompression illness (DCI) results from liberation of gas bubbles in the blood and tissues. DCI may be classified as decompression sickness (DCS) or arterial gas embolism (AGE), depending on where the gas bubbles lodge. DCS occurs after longer exposures to a hyperbaric environment with correspondingly larger up-take of inert gas. DCS may be classified into type 1 with cutaneous symptoms and musculoskeletal pain only or type 2 with neurologic and/or pulmonary symptoms as well. AGE usually results from a pulmonary barotrauma, and with cerebral arterial involvement, the symptoms are similar to a stroke.The most important therapy, in the field, is oxygen resuscitation with the highest possible concentration and volume delivered. The definitive treatment is rapid recompression with hyperbaric oxygen therapy. Additional therapeutic measures are discussed.

Hemodynamic responses to dexmedetomidine in critically injured intubated pediatric burned patients: a preliminary study.

Because of ineffectiveness and tolerance to benzodiazepines and opioids developing with time, drugs acting via other receptor systems (eg, &agr;−2 agonists) have been advocated in burn patients to improve sedation and analgesia. This study in severely burned pediatric subjects examined the hemodynamic consequences of dexmedetomidine (Dex) administration. Eight intubated patients with ≥20 to 79% TBSA burns were studied between 7 and 35 days after injury. After baseline measurements of mean arterial blood pressure and heart rhythm were taken, each patient received a 1.0 µg/kg bolus of Dex followed by an ascending dose infusion protocol (0.7–2.5 µg/kg/hr), with each dose administered for 15 minutes. There was significant hypotension (27±7.5%, average drop in mean arterial pressure [MAP] ± SD), and a decrease in heart rate (HR; 19% ± 7, average drop in HR ± SD). The average HR decreased from 146 beats per minute to 120. No bradycardia (HR < 60) or heart blocks were observed. In three patients, the MAP decreased to <50mm Hg with the bolus dose of Dex. Of the remaining five patients, three patients completed the study receiving the highest infusion dose of Dex (2.5 µg/kg/hr), whereas in 2 patients the infusion part of the study was begun, but the study was stopped due to persistent hypotension (MAP < 50mm Hg). These observations indicate that a bolus dose of Dex (1.0 µg/kg for 10 minutes) and high infusion rates may require fluid resuscitation or vasopressor support to maintain normotension in critically injured pediatric burn patients.

Anesthetic management for thoracopagus twins with complex cyanotic heart disease in the magnetic resonance imaging suite.

We report a case of thoracopagus twins undergoing magnetic resonance imaging (MRI) studies under general anesthesia. The twins had a complex shared cardiac anatomy that posed additional challenges to an already-difficult anesthesia care area. This report emphasizes the approach to anesthetic management of conjoined twins in the MRI environment.

Der schwere Tauchunfall

ZusammenfassungDer schwere Tauchunfall ist ein potentiell lebensbedrohliches Ereignis, verursacht durch raschen Abfall des Umgebungsdrucks, der bei Tauchern und anderweitig überdruckexponierten Personen beobachtet wird.Hervorgerufen durch die Bildung freier Gasblasen im Blut und Geweben kann die Dekompressionserkrankung (DCI) abhängig vom Entstehungsmechanismus in Dekompressionskrankheit (DCS) und arterielle Gasembolie (AGE) unterschieden werden. Die DCS tritt nach längerem Aufenthalt im Überdruck und entsprechender Inertgasaufsättigung auf. Die AGE ist typischerweise die Folge eines pulmonalen Barotraumas, die Symptomatik ist bei zerebralem Befall der eines Schlaganfalls ähnlich.Wichtigste Sofortmaßnahmen sind die schnellstmögliche Gabe von Sauerstoff in höchstmöglicher Konzentration und die Volumentherapie. Wichtigste weiterführende Maßnahme ist die schnellstmögliche Rekompression in einer Therapiedruckkammer mit hyperbarem Sauerstoff. Der Transport der Verunfallten sollte möglichst erschütterungsfrei, bei Lufttransport ohne weitere Reduktion des Umgebungsdrucks erfolgen. Weitere, ergänzende Therapiemaßnahmen werden kontrovers diskutiert.AbstractDecompression injuries are potentially life-threatening incidents, generated by a rapid decline in ambient pressure. Although typically seen in divers, they may be observed in compressed air workers and others exposed to hyperbaric environments.Decompression illness (DCI) results from liberation of gas bubbles in the blood and tissues. DCI may be classified as decompression sickness (DCS) or arterial gas embolism (AGE), depending on where the gas bubbles lodge. DCS occurs after longer exposures to a hyperbaric environment with correspondingly larger up-take of inert gas. DCS may be classified into type 1 with cutaneous symptoms and musculoskeletal pain only or type 2 with neurologic and/or pulmonary symptoms as well. AGE usually results from a pulmonary barotrauma, and with cerebral arterial involvement, the symptoms are similar to a stroke.The most important therapy, in the field, is oxygen resuscitation with the highest possible concentration and volume delivered. The definitive treatment is rapid recompression with hyperbaric oxygen therapy. Additional therapeutic measures are discussed.

[Severe diving accidents: physiopathology, symptoms, therapy].

ZusammenfassungDer schwere Tauchunfall ist ein potentiell lebensbedrohliches Ereignis, verursacht durch raschen Abfall des Umgebungsdrucks, der bei Tauchern und anderweitig überdruckexponierten Personen beobachtet wird.Hervorgerufen durch die Bildung freier Gasblasen im Blut und Geweben kann die Dekompressionserkrankung (DCI) abhängig vom Entstehungsmechanismus in Dekompressionskrankheit (DCS) und arterielle Gasembolie (AGE) unterschieden werden. Die DCS tritt nach längerem Aufenthalt im Überdruck und entsprechender Inertgasaufsättigung auf. Die AGE ist typischerweise die Folge eines pulmonalen Barotraumas, die Symptomatik ist bei zerebralem Befall der eines Schlaganfalls ähnlich.Wichtigste Sofortmaßnahmen sind die schnellstmögliche Gabe von Sauerstoff in höchstmöglicher Konzentration und die Volumentherapie. Wichtigste weiterführende Maßnahme ist die schnellstmögliche Rekompression in einer Therapiedruckkammer mit hyperbarem Sauerstoff. Der Transport der Verunfallten sollte möglichst erschütterungsfrei, bei Lufttransport ohne weitere Reduktion des Umgebungsdrucks erfolgen. Weitere, ergänzende Therapiemaßnahmen werden kontrovers diskutiert.AbstractDecompression injuries are potentially life-threatening incidents, generated by a rapid decline in ambient pressure. Although typically seen in divers, they may be observed in compressed air workers and others exposed to hyperbaric environments.Decompression illness (DCI) results from liberation of gas bubbles in the blood and tissues. DCI may be classified as decompression sickness (DCS) or arterial gas embolism (AGE), depending on where the gas bubbles lodge. DCS occurs after longer exposures to a hyperbaric environment with correspondingly larger up-take of inert gas. DCS may be classified into type 1 with cutaneous symptoms and musculoskeletal pain only or type 2 with neurologic and/or pulmonary symptoms as well. AGE usually results from a pulmonary barotrauma, and with cerebral arterial involvement, the symptoms are similar to a stroke.The most important therapy, in the field, is oxygen resuscitation with the highest possible concentration and volume delivered. The definitive treatment is rapid recompression with hyperbaric oxygen therapy. Additional therapeutic measures are discussed.