Q. Rune. South Texas College of Law.
That procedure really “set the stage” for all therapeutic catheterization procedures used today buy cleocin 150 mg on line skin care heaven. In 1967 generic 150 mg cleocin with amex acne under beard, Porstmann and colleagues reported the first nonsurgical corrective procedure in the catheterization laboratory with their description of a technique for closure of a patent ductus (3) purchase 150 mg cleocin with amex acne solutions. Even though their device has not found widespread use, it set the stage for future development of transcatheter devices. One of the largest contributions to interventional cardiology has probably been made by Gruentzig, a Swiss-native who in 1976 reported on dilation of peripheral vessels with noncompliant balloons. This initiated a rapid innovative spurt within the congenital cardiac community during which narrowed lesions at various locations were treated with balloon angioplasty, frequently initially in a noncontrolled fashion. Jean Kan reported the first successful transcatheter static balloon pulmonary valvuloplasty (6) and Dr. Charles Mullins introduced endovascular stents into the management of patients with congenital cardiac lesions (8), and the long list of innovations reached another milestone when Dr. Phillip Bonhoeffer, a German cardiologist working in France in 2000, performed the first transcatheter pulmonary valve replacement in a human (9). Transcatheter valve therapies and other interventional therapies to treat patients with structural heart disease have rapidly increased over the last few years. These therapies are not limited anymore to patients with congenital heart disease. In this section, the most important therapeutic catheterization procedures performed as of this writing are discussed. This chapter is not intended as a complete and exhaustive textbook of interventional techniques, but instead should give the reader a general overview of therapeutic catheterization. Acknowledgment We have used and expanded upon this chapter published in other editions of this textbook and therefore acknowledge the previous contributions made by Drs. It should be emphasized that not every pediatric cardiologist, or, for that matter, every center, should offer every therapeutic catheterization procedure. For any procedures to be performed at any particular institution, minimal specific skills are required, special techniques must be mastered and maintained, and a large inventory of specialized and expensive catheters and devices must be stocked to offer the patient an optimal procedure. Absence of appropriate qualifications and equipment can result in unnecessary risk to the patient without a reasonable chance of the therapeutic catheterization procedure being successfully accomplished. In fact, even if the patient is not acutely harmed by the attempt, it is important to be aware of the fact that the next procedure in a more appropriate setting might be compromised by a previously unsuccessful attempt. Adverse Events and Quality Improvement For many years, reporting of procedure-related adverse events was limited mostly to single-center retrospective experiences, often without any clearly and consistently applied criteria of what would be considered an adverse event, and how its severity should be defined (11,12,13). The data derived from these registries often provided the only prospective multicenter outcome data for many procedure types. This registry documented not insignificant rates of adverse events, 10% for diagnostic cases, and 20% for interventional procedures. Higher severity (level 3 to 5) adverse events occurred in 9% of interventional cases, and 5% of diagnostic cases. The incidence of life-threatening adverse events has been reported to be as high as 2. However, to accurately compare adverse event rates and outcome between institutions and operators, an adjustment for case mix and hemodynamic vulnerability is required. Following the definition of procedure-type risk groups, Bergersen and colleagues reported on hemodynamic variables associated P. The Interventional Armamentarium General Considerations The spectrum of transcatheter procedures available for the treatment of children and adults with congenital heart disease has rapidly increased over the last three decades. With rapid progress that is being made in the development of new and more refined equipment, the operator has an inherent responsibility to keep up-to-date with these development efforts and to avoid procedural failures in situations where the use of a different type of equipment may lead to a very different outcome. Even though many interventional meetings have a focus on new device developments, the choice of appropriate balloons, catheters, sheaths and wires is in many situations even more important for a successful outcome. It is beyond the scope of this discussion to describe all available balloon catheters, but the operator has to make a well- informed decision on which balloon to use, based on profile, rated maximum pressure, available lengths, and degree of compliance and adjust his/her choice to suit specifically the therapeutic intervention that is intended. Even though transcatheter devices have long been available for the management of congenital cardiac lesions, the greatest progress has been made through introduction of a large variety of newer devices that were specifically developed for individual congenital cardiac lesions over the last 10 years. This progress has enabled many procedures to be safely performed in a much wider range of clinical centers. In this chapter, a variety of device-specific sections have been taken with permission from an article on this topic that was published in “Expert Review of Medical Devices” (29). The spectrum of devices that are discussed below is not intended to be complete, but rather represents subjective choices of the authors. Devices for the treatment of structural cardiac lesions or the treatment of acquired heart disease are not included in this chapter. The procedure was complicated and required a large arterial cannulation and as a result, this technique never found widespread use. Rashkind and Cuaso, while still working on the septostomy balloon, also developed a device for closure of the patent ductus. This device was a small umbrella that attached to the ductus by tiny hooks at the ends of the umbrella arms. It was modified into a double umbrella, which fixed in the ductus by a spring mechanism of the arms expanding against the vessel walls. However, the extensive experience gained in this process formed the basis upon which virtually all subsequent devices have been developed. A large variety of devices have been developed to facilitate occlusion of vascular structures. Embolization coils have been used by general interventional radiologists for almost three decades (4). However, it was not until the 1980s that these were introduced into the interventional armamentarium of the pediatric cardiologist, initially for occlusion of abnormal collateral vessels (40), and subsequently in 1992 for the occlusion of the patent arterial duct in children (41). However, these are less frequently used in congenital cardiac interventions and are therefore will not be further discussed in this review. The most common indications for stent placement include rehabilitation of branch pulmonary artery stenosis as well as treatment of primary and recurrent coarctation of the aorta or aortic arch obstructions. However, stents are also used to rehabilitate stenotic lesions in systemic and pulmonary veins, and to maintain patency of structures that would otherwise close, such as the arterial duct or a foramen ovale. Endovascular stents are particularly helpful in locations that are either inaccessible to surgical techniques, or where the scarring resulting from surgical intervention is unlikely to achieve an improvement of the lesion, which applies to thin-walled vessels such as distal pulmonary arteries or pulmonary veins. The choice of which stent to use for a particular lesion, depends not only on age and size of the patient, but also on expected adult dimensions of the vascular structure that is being treated, the morphology of the specific lesion, the presence of side branches that need to be crossed, expected future surgical procedures as well as previous surgical and transcatheter procedures and their outcome. An ideal stent would combine a variety of characteristics, which are often exclusive to each other and may require opposing design goals: Low profile that allows introduction through small delivery sheaths. Possibility for re-expansion with maximum achievable diameter being sufficient to accommodate the growth of a vessel to adult size.
Although this can orbital wall and allows removal of the residual medial max- be achieved through an inferior meatal puncture order discount cleocin acne juvenil, place- illa without endangering the orbit order online cleocin skin care equipment wholesale. Most large tumors of the ment of a 4–mm microdebrider blade through the inferior maxillary sinus and/or pterygopalatine fossa will involve the meatal antrostomy tends to destabilize the inferior turbi- posterior ethmoids and sphenoid buy 150 mg cleocin free shipping skin care md. This lary fap is performed and the frontal recess dissected with is because the nasal vestibule provides a fulcrum around exposure of the frontal ostium. The bulla ethmoidalis is re- which the blade is rotated, causing signifcant disruption moved and a posterior ethmoidectomy and sphenoidotomy 200 16 Endoscopic Resection of Tumors 201 A, B C Fig. The white arrow indicates the trephination port in the anterior face of the maxillary sinus. Any tumor large intranasal component of a soft nonvascular tumor, the extension into the anterior and posterior ethmoids can be tumor is debulked (Fig. If the tumor is very vascular or assessed and, if necessary, biopsies or frozen sections of the frm then it can be pushed superiorly or partially debulked. This Because of the posterior location of angiofbroma, debulking helps ensure complete tumor clearance. To perform the medial maxillectomy, the inferior tur- Turbinectomy scissors are used to cut along the crushed binate is medialized. A Tilley’s packing forceps is used to region of the inferior turbinate up to the point where the crush the turbinate just distal to the junction of the anterior turbinate inserts into the lateral nasal wall (Fig. Here the mucosal incision is turned ver- tically toward the posterior region of the maxillary sinus antrostomy. A sharp chisel is used to cut the bone under the mucosal incisions following the mucosal incision (Fig. The posterior vertical cut needs to enter the maxillary sinus adjacent to the posterior wall of the maxillary sinus and into the large antrostomy5 (Fig. Once the bone forming the medial maxillary wall is mobilized, the nasolacrimal duct will tether the bone an- teriorly and the duct will be visualized (Fig. Note the microdebrider blade that has been placed through the canine fossa trephine. Tumor can now be sinus, further resection of the anteromedial wall and frontal removed from the maxillary sinus under direct visualization. In such If additional access is required and the tumor does not attach cases a canine fossa trephine is not thought to be suitable due to the anterior wall of the maxillary sinus, a canine fossa to the small risk of seeding the tumor into the soft tissues of puncture can be performed. Although seeding is unlikely to occur, this risk is endoscope to be introduced through the anterior wall of the thought to be greater if the entry point into the maxillary sinus maxillary sinus which can be useful to access areas within the is through tumor rather than through normal mucosa. This access is achieved the required angle for dissection in difcult areas such as the by performing a hemitransfxion incision in the opposite nasal anterior wall or anterolateral region of the maxillary sinus. The instrument can then that attaches extensively to the anterior face of the maxillary be passed through the hemitransfxion incision, through the Fig. This allows the passage of a 70-degree dia- fxion incision anteriorly in the left nostril (contralateral side to the mond tipped drill (D). C, carti- right nasal cavity demonstrating the working tip of the drill passing into lage; F, fap. The mucosa giving greater access to the anterior wall of the maxillary sinus from the posterior wall of the maxillary sinus is elevated (Fig. This exposes the bone and removal of this of approach and usually allows complete access to the entire bone is necessary to expose the pterygopalatine fossa. The punch Access to the Pterygopalatine Fossa (Videos 41 and 42) is introduced into the sphenopalatine foramen and the bone anterior to the foramen removed until the posterior Access to the pterygopalatine fossa is achieved by remov- wall of the maxillary sinus is reached (Fig. In most cases removal of this bone can be done either with the punch a medial maxillectomy is unnecessary as most of the ptery- or with a 45-degree through-biting Blakesley. Bone is re- gopalatine fossa can be accessed through a large middle moved until the contents of the pterygopalatine fossa are meatal antrostomy. In addition the vidian nerve enters the posterior aspect of the fossa before moving laterally to end in the pterygopalatine ganglion which is suspended from the maxillary nerve (Fig. The pterygopala- tine fossa narrows gradually as it opens laterally into the region of the infraorbital fssure and pterygomaxil- lary fssure before widening into the infratemporal fossa (Figs. The roof of the pterygopalatine fossa is formed by the greater wing of the sphenoid bone and the infraorbital fssure, foramen rotundum, and the maxillary nerve coursing from the foramen rotundum from medial to lateral across the roof of the fossa just below the orbital apex (Figs. The frst fact to be appreciated is that the pterygopalatine fossa forms a relatively small part of the total area behind the posterior wall of the maxillary sinus Access to the Infratemporal Fossa (Videos 41 and 42) (Fig. Second the frst structures to be encountered when entering the fossa are the blood vessels (Fig. To access the infratemporal fossa, all of the bone of the pos- The neural structures all lie deep to this plexus of arteries terior and lateral wall of the maxillary sinus needs to be (Fig. Most of the bone can be removed through the same Further dissection in the roof to the fossa allows the maxil- nostril as the tumor using either the Hajek-Kofer punch or lary nerve to be seen just below the orbit in the roof of the through-biting Blakesley. If this nerve is followed posteromedially the foramen should be removed from the roof to the foor of the maxillary rotundum can be seen (Fig. The septal port for the infratemporal fossa is very similar to that The Endoscopic Anatomy of the Infraorbital Fissure used to access the front wall of the maxillary sinus. This angle of approach allows the instruments to be advanced up to the The other relationship that is important to understand is anterior maxillary sinus wall as described under “Maxillary how the pterygopalatine fossa and infratemporal fossa relate Sinus Access. It is through this fssure that tumors can extend from the infratemporal fossa and pterygopalatine fossa up toward the orbital apex. Additionally, tumors may follow the infraorbital nerve and maxillary nerve to enter Endoscopic Anatomy the pterygopalatine fossa and move posteriorly toward the cavernous sinus and carotid artery. Endoscopic Anatomy of the Greater Palatine Canal As the orbital apex and sphenoid is approached, the inferior and the Pterygopalatine Fossa portion of the lamina papyracea thickens. The lateral wall of the fssure is formed by the medial wall of the middle cranial The greater palatine canal and the pterygopalatine fossa fossa. The pterygopala- infraorbital fssure and it is around this structure that tumor tine fossa is similar to an inverted cone and the bottom can insinuate to reach the orbital apex and then expand into 208 Endoscopic Sinus Surgery D Fig. The vidian canal can be seen entering the white line and the sphenopalatine foramina are indicated with the white ar- posterior wall of the pterygopalatine fossa (black arrow). The posterior wall of the maxillary sinus has the infraorbital fissure are continuous with each other. Signifcant expansion can occur so that the tumor may reach the cavernous sinus and even the carotid artery. To understand how the medial aspect of the infra- orbital fssure can be surgically accessed, Figs. Note how the medial part of the fssure communicates with the pterygopalatine fossa whereas the lateral part of the fssure communicates with the orbit. Note the landmarks of the lateral wall including the optic nerve, the anterior genu of the intracavernous carotid artery, the maxillary impression for the maxillary division of the trigeminal nerve, and the vidian nerve in the foor of the sphenoid sinus. The blue silicone shows the anterior genu of the intracavernous carotid is completely within the cavernous sinus. The anterior limit of this marks the beginning of the orbital apex, the supraorbital fssure. The occulomotor, trochlea, and ophthalmic division of the tri- geminal nerve can be seen in Fig. In this image the periorbita of the orbital apex has been retracted with a Freer dissector.
Moderate versus deep operative brain injuries do not worsen with surgery in neo- hypothermia for the arterial switch operation – experience nates with congenital heart disease buy 150mg cleocin with amex acne map. Primary arterial switch rial switch operation in patients with transposition of the great operation in children presenting late with d-transposition of arteries and abnormalities of the mitral valve or left ventricu- great arteries and intact ventricular septum cleocin 150mg for sale skin79 skin care. Eur J Cardiothorac Surg switch operation for transposition of the great arteries with 2003 order 150mg cleocin with visa acne 7 days past ovulation;24:1–9. J Thorac dictors of aortic root dilation and aortic regurgitation after Cardiovasc Surg 1993;106:111–15. Successful two stage correction of transposition in transposition of the great arteries: impact on outcome. Arrhythmias and operation in the treatment of transposition of the great intracardiac conduction after the arterial switch operation. Current quality of life after surgical repair of transposition of the results with the Mustard operation in isolated transposition of great arteries: atrial versus arterial switch operation. Length of stay the left ventricle after arterial switch operation for transposi- after infant heart surgery is related to cognitive outcome at age tion of the great arteries. Early results for anatomic correction ease on brain development and neurodevelopmental outcome. J Thorac Cardiovasc Surg tors infuencing early mortality of the arterial switch opera- 2007;133:461–9. J and complete transposition of the great arteries: a technical Thorac Cardiovasc Surg 2008;135:331–8. Eur J Cardiothorac Surg obstruction after the arterial switch operation for transpo- 2010;37:1239–45. Protooncogene induc- lowing the arterial switch operation for transposition of the tion and reprogramming of cardiac gene expression produced great arteries. Rapid, two-stage arte- anatomy after arterial switch operation for transposition of rial switch for transposition of the great arteries and intact the great arteries: detection by 16-row multislice computed ventricular septum beyond the neonatal period. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu of the perioperative neurologic effects of hypothermic circula- 2000;3:198–215. Patterns of devel- tolic mechanics late after an acute pressure overload stimulus opmental dysfunction after surgery during infancy to cor- in infancy. Developmental and and aortopulmonary shunt placement for transposition of the neurological status of children at 4 years of age after heart great arteries with low left ventricular pressure. Judgement of the left ventricle retraining in the rapid two stage-switch operation. Isolated primary congeni- tal aortic regurgitation where the valve itself is congenitally In Chapter 14, Choosing the Right Biomaterial, the many structurally abnormal is a relatively rare entity, certainly options available for valve replacement are described. Chapter 14 also emphasizes that all presently available valve replacement options have important disadvantages. Most Anatomy importantly, all replacement options including the Ross pro- Primary Congenital Aortic Valve Regurgitation cedure do not incorporate growth potential. For this reason, Congenital aortic valve regurgitation is often the result of valve repair is preferred for essentially all congenital valve 3,4 incomplete formation of a bicuspid valve. Although repair does not create a perfect valve nary leafet is frequently affected. It may be very hypoplastic it does allow the child to live a good quality life, free of the and incompletely fused with either the non or left leafet. The risk of thromboembolism and free of the need to take anti- resulting fused leafet may have poor commissural support coagulant medication. However, there is hope 1 secondary to the large volume load passing through the valve. The regurgitant jet also damages the free edges of the valve leafets which become thickened and rolled. The management of isolated approximately 13% of patients immediately following bal- congenital aortic valve stenosis in neonates, infants, and chil- loon dilation, increasing to 38% during follow-up. In the neonate, if there is associated common anatomical problem that was seen was detachment underdevelopment of left heart structures, for example mitral of the right coronary leafet at the anterior commissure (Fig. This probably results from the tendency of the balloon undertaking a Norwood procedure and embarking on the to straighten out relative to the posterior curve of the arch single-ventricle track. In an analysis of 21 replacement, either by a transfemoral or a transventricu- valves by Bacha et al. Increasing experience from the membrane onto the undersurface of one or more with dilation of the aortic valve has meant that it is unusual leafets and distort the leafet. This can occur when the mem- to see more than moderate regurgitation early or late follow- brane is causing minimal obstruction and the gradient across ing the interventional catheter procedure though perhaps the it is low, for example less than 20 mm. As aortic regurgita- need for repeat dilation because of residual stenosis has been tion progresses the leafets may become thickened and rolled more common. A long-standing Connective tissue disorders such as Marfan’s syndrome and jet can result in prolapse of this valve leafet secondary to Ehlers–Danlos syndrome are associated with aortic root the Venturi effect of the jet (Fig. Thus the ventricle is volume-loaded and must dilate Aortic regurgitation is seen in association with a number to cope with this increased workload. With severe regurgitation it is possible to ondary to injury or scarring of the aortic valve caused by see retrograde fow in the descending aorta which compro- bacterial endocarditis. Although the single semilunar valve mises mesenteric fow in particular, which can be danger- in patients with truncus arteriosus is not strictly an aortic ous for example in the neonate with truncus and associated valve, it has the functional role of such. Severe regurgitation will result in the usual signs of 398 Comprehensive Surgical Management of Congenital Heart Disease, Second Edition congestive heart failure, particularly failure to thrive. There the cross-clamp and also to avoid air embolism through poor are numerous readily detectable clinical signs including timing of left heart vent insertion. Following the commence- Watson’s water hammer pulses, Traube’s pistol-shot sounds ment of cardiopulmonary bypass, cooling to mild hypother- over the femoral arteries, and deMusset’s head bobbing in mia, for example 30–32°C is gradually begun. The diastolic blood pressure may be very be slower than usual to minimize the risk of early ventricu- low or unobtainable. The aortic cross-clamp is applied before the heart becomes distended as it cools because of bradycardia Diagnostic Studies and reduced contractility. Three-dimensional echo reconstruction of the valve introduces risks of air embolism and inadequate perfusion can be very helpful in planning surgical reconstruction. The remainder of the frst dose of cardio- Medical and Interventional Therapy plegia is infused selectively into both coronary ostia. There are no interventional catheter techniques that are use- A decision to perform valve reconstruction is at the sur- ful for aortic valve regurgitation. Anatomic elements necessary for valve repair tation although it has been reported. It is important to understand that the goal in treating aortic Primary Repair Excess fbrous tissue, which has a tendency regurgitation in the young child is to avoid valve replacement.
The director will need to keep in contact with government ofcials and should convey the needs for medical resources in this time of emergency purchase cleocin 150mg free shipping acne vulgaris causes. Outside agencies and organizations should be con- tacted as well to seek additional help with medical resources order cleocin with mastercard acne jawline. At this point buy cheap cleocin online skin care doctors edina, medical resources should be the most sought after items as well as facilities that can be converted into hospital space, which is currently in short supply. Additionally, you will need to locate facilities that can also serve as a temporary morgue. The bodies will need to be taken somewhere to isolate the corpses since the chemical will still be present on their clothes and bodies. Anyone who removes or contacts any person (or corpse for that matter) should wear protective gear and respira- tors when making physical contact with the person. Key Issues Raised from the Case Study The government ignored the safety shortfalls at the plant and this played a part in the Bhopal tragedy. For government ofcials and administrators this case study should demonstrate what can go terribly wrong when safety precautions and safety standards are below industry standards. The full extent of damage 128 ◾ Case Studies in Disaster Response and Emergency Management will never be known concerning the health and well-being of the citizens of Bhopal. With a plant that has the capacity to produce a deadly by-product, administrators should be prepared for a worst-case scenario and maintain a read- ily accessible inventory of items like gas masks for anyone in the immediate vicin- ity of the industrial complex. Additionally, this case study also points out that economic development does not justify tolerating conditions that can be danger- ous for the population. Items of Note Union Carbide Corporation would eventually pay the Indian government $470 million to compensate the victims of Bhopal (Broughton, 2005). The payment was based on the information that 3,000 people had been killed and another 102,000 had been permanently disabled by the chemical release. Union Carbide Corporation closed the plant at Bhopal but did not clean up the site. Texas City Disaster, 1947 Stage 1 of the Disaster You are the city manager for a midsized city (16,000 residents) in the Southwest part of the United States. Your city has been a main deep water shipping port for agricultural products and industrial products with railroad line access since 1911. The city has a large chemical and petroleum industry that has several facilities throughout the city (Moore Memorial Public Library, 2007). It would be essential to know what chemicals exist in the municipality and to have trained teams to contend with such hazards. A starting point would be for the city to map locations where storage tanks and any type of infrastructure that contends with chemicals currently reside. In addition, the city’s police and fre departments should carry out training exercises on how to contend with such disasters. Additionally, hospitals should have resources on hand to treat patients with chemical injuries. If the resources are available, the city’s fre department should carry out regular safety and compliance inspections on any large plant that handles chemical manufacturing. The city should have a response plan for industrial accidents and an efective evacuation plan for any businesses and residences near large manufacturing plants. What resources should you have on hand for the emergencies that you think could possibly occur? A hazardous materials team should be available to the fre department as well as freboats and an aerial frefghting plane that can dump large amounts of chemicals on fres. A city man- ager should attempt to make regional agreements with other city managers that in times of crisis, cities will assist each. Grandcamp is currently docked at your port city and is carrying a cargo of small arms ammunition and taking on a cargo of over 2,300 tons of ammonium nitrate fertilizer (Moore Memorial Public Library, 2007). Does this ship pose a hazard to your city, and if so, what measures will you take to ensure the safety of your city and industrial facilities? The city manager should be concerned with a ship carrying this type of explosive ordinance combined with a chemical that is a component used to make gunpowder. The city man- ager needs to ensure that all safety procedures are being followed by the ship’s captain and crew while they are in the port. What policies and procedures should you have in place for ships carrying this type of cargo? A ship carrying this type of cargo should declare its inventory to the city fre department, type and amount. Furthermore, ships carry- ing this type of cargo should be berthed in an isolated area of the har- bor so that if something does go wrong, it will not impact other ships or infrastructure. The fre department should mobilize all of its resources immediately to combat the blaze. The city manager should stay in close contact with the fre department and alert hospitals that a crisis is currently unfolding. In addition, the city manager should seek out assistance from sur- rounding municipalities and state ofcials. If possible, the ship needs to be moved well away from any infrastructure and other ships. If the ship cannot be moved, then other ships that are in the vicinity need to be moved away from the area. Additionally, there is no telephone service since the telephone operators are on strike and there is no one to perform their function. You have dis- patched the city’s two fre trucks and the volunteer frefghters have arrived on the scene with an additional two fre trucks, but the fre cannot be contained with just water (Moore Memorial Public Library, 2007). The city manager needs to make sure that the area is cleared of workers and citizens to avoid casualties. If possible, an airplane equipped with fre-retardant chemicals needs to be obtained to help fght the blaze. Since you have no electronic communica- tions through the telephone system, other means will need be made available, such as setting up runners or getting volunteers with short-wave radios to assist with communication eforts. Since you have no hazardous materials team, local ofcials and state ofcials need to be contacted to obtain critical resources that can be used to fght a chemical fre. You need to make a public plea for the telephone operators to come back to work and of strike so that your communication system will be operable. Stage 5 of the Disaster The ship’s crew had only been able to remove 3 of 16 boxes of small arms ammuni- tion. In an attempt to douse the blaze, the captain of the ship has had steam poured into the cargo hold. Unfortunately, the steam turned the ammonium nitrate into poisonous nitrous oxide gas vapors, which fll the ship.