By K. Cyrus. Institute for Christian Works. 2019.
Prevention and treatment Chance of pulmonary aspiration can be minimized by - Fasting - Naso-gastric tube decompression If aspiration of gastric content occurs buy 50 mg penegra free shipping; an endotracheal tube should be placed and the air way suctioned and lavaged buy penegra 50 mg online. This often results in re- alignments of the bowel loops and relief of the obstruction buy penegra 100mg on-line. If the obstruction doesn’t respond within 48-72 hours, re- operation is necessary. Inability of the patient to void is often due to pain caused by using the voluntary muscles to start the 31 urinary stream. Urinary tract infection Predisposing factors Pre-existing contamination of the urinary tract Catheterization Clinical presentation • Fever • Suprapubic or flank tenderness • Nausea and vomiting Investigation -Urine analysis (pus or bacteria will be seen in the urinary sediments) Treatment Increase hydration Encourage activity. Hematoma, Abscess and Seromas These may occur either in the pelvis or under the fascia of abdominal rectus muscle. They are suspected during falling of hematocrite in association with low-grade fever. Small hematoma or seroma often resolve spontaneously, but some can become infected. List important laboratory investigations which need to be done in almost all pre-operative patients despite the specific diagnosis. The properties of the most frequently used antiseptics and their use in surgical and traumatic wounds. How choose the most suitable antiseptics for his/her institution Introduction The most serious outcome (important factor) of impaired wound healing is infection. Antiseptics and aseptic techniques are used in an attempt to prevent contamination to an acceptable level making the wound less receptive to bacterial growth. It should be noted, however, that the corner stones in decreasing wound infection are: gentle tissue handling, sharp dissection, good homeostasis, and accurate apposition of wound edge without tension. Proper wound debridement (wound excision) is vital in post traumatic wounds to prevent infection. Therefore, knowledge of aseptic and antiseptic techniques is very important for the medical practitioner, be it in the ward, minor/major operation theaters or in the emergency out patient department: this knowledge can help prevent infection, unnecessary morbidity and some times mortality of patients. Cross infection: the transfer of microbes in hospitalized patients to other patients. It would be resistant to inactivation by organic materials, such as blood & feces c. There would be no toxicity or allergic reaction, and the antiseptic should be non – staining d. The source of infection in surgical wounds can be: • The patient • Staff (a healthy carrier, incubating an infectious disease or with overt clinical illness) • The operation room • Occasionally instruments. Preventative Measures • Short hospital stay preoperatively • Shower a day before surgery • Treatment of any infectious site before surgery • Aseptic methods with sterile equipment for all procedures. Staff Wear clean clothes, shoes or covers, mask and cap or hood beyond the green line Scrubbing up of all operating team before each operation for at least 5 minutes with an antiseptic soap or detergent. Finally, dry with sterile towel and apply 70% alcohol or Povidone iodine if available. Operating Room There are few bacteria in the air of an empty theatre but every individual liberates about 10,000 organisms per minute into the air. Therefore, to decrease airborne infections, keep the number of personnel reduced to a minimum. If there is no system to provide this, windows should be open to allow ingress of fresh outside air and escape of anesthetic gases. At regular intervals, conduct a more thorough cleaning by mopping the floor and washing the walls with detergents. Instruments All instruments and garments to be used in surgical procedures must be sterile and this is attained by sterilization. Sterilization: - is a process by which inanimate objects are made free of all microorganisms. It uses steam at a pressure of 750 0 mmHg above atmospheric pressure and temperature of 120 C for 15-30 minutes. Appropriate indicators must be used each time to show that the sterilization is accomplished. Noxythiolin:- Releases formaldehyde in contact with tissues, broad spectrum, expensive, weak and slowly bactericidal Alcohol plus chlorhexidne Alcohol plus povidon iodine useful mixtures Chlorhexidine plus cetrimide 40 Review Questions 1. Using your knowledge of the properties of the different antiseptics which one would you choose for your heath center? What is the most important measure you would take for a patient who comes to the emergency room with a contaminated wound? Types of Suture Materials Suture materials can generally be classified as absorbable and non absorbable. Catgut (natural or biologic type) Vicryl (Synthetic) Non absorbable: This is a type of suture material that remains unabsorbed by the tissue. Figure 2: Continuous Sutures Useful Tips: • Place a single suture and ligate but only cut the short end of the suture. Figure 3: Mattress Sutures Fig 3 a: Horizontal Fig 3 b: Vertical Mattress sutures may be either vertical or horizontal. Small bites of the subcuticular tissues on alternate sides of the wound are taken and then pulled carefully together. Introduction Successful wound management with rapid and complete healing and minimal complication depends on understanding the basic principles of assessment, bacteriology and application of the general principles of wound care. The primary goal of wound management is to aid the natural body process to produce optimal functional and cosmetic result. This requires an understanding of the basic principles of wound care and the process of healing. Failure to do this may result in delay of healing and unwanted secondary complications which may be distressing to the physician, patient and family and may lead to greater economic loss. It is caused by a transfer of any form of energy into the body which can be either to an externally visible structure like the skin or deeper structures like muscles, tendons or internal organs. There are integrated sequences of events leading to cellular proliferation and remodeling. It is characterized by vaso-constriction, clot formation and release of platelets and other substances necessary for healing and help as a bridge between the two edges. It is characterized by classical inflammatory response, vasodilatation and pouring out of fluids, migration of inflammatory cells and leukocytes and rapid epithelial growth. It is characterized by fibroblast, epithelial and endothelial proliferation, Collagen synthesis, and ground substance and blood vessel production. Equilibrium between protein synthesis and degradation occurs during this phase with cross linking of collagen bundles leading to slow and continuous increase in tissue strength of the wound to return to normal. Clinical types of healing Traditionally, wound healing can be classified into three clinical types: Healing by first, second and third intention. Healing by first intention: This is a type of healing of clean wound closed primarily to approximate the ends.
The intrinsic muscles (those within the tongue) are the longitudinalis inferior generic 50mg penegra free shipping, longitudinalis superior order penegra 100mg, transversus linguae order penegra 100mg with mastercard, and verticalis linguae muscles. As you learned in your study of the muscular system, the extrinsic muscles of the tongue are the mylohyoid, hyoglossus, styloglossus, and genioglossus muscles. The mylohyoid is responsible for raising the tongue, the hyoglossus pulls it down and back, the styloglossus This OpenStax book is available for free at http://cnx. Working in concert, these muscles perform three important digestive functions in the mouth: (1) position food for optimal chewing, (2) gather food into a bolus (rounded mass), and (3) position food so it can be swallowed. The top and sides of the tongue are studded with papillae, extensions of lamina propria of the mucosa, which are covered in stratified squamous epithelium (Figure 23. Fungiform papillae, which are mushroom shaped, cover a large area of the tongue; they tend to be larger toward the rear of the tongue and smaller on the tip and sides. Fungiform papillae contain taste buds, and filiform papillae have touch receptors that help the tongue move food around in the mouth. The filiform papillae create an abrasive surface that performs mechanically, much like a cat’s rough tongue that is used for grooming. Lingual glands in the lamina propria of the tongue secrete mucus and a watery serous fluid that contains the enzyme lingual lipase, which plays a minor role in breaking down triglycerides but does not begin working until it is activated in the stomach. A fold of mucous membrane on the underside of the tongue, the lingual frenulum, tethers the tongue to the floor of the mouth. People with the congenital anomaly ankyloglossia, also known by the non-medical term “tongue tie,” have a lingual frenulum that is too short or otherwise malformed. The Salivary Glands Many small salivary glands are housed within the mucous membranes of the mouth and tongue. These minor exocrine glands are constantly secreting saliva, either directly into the oral cavity or indirectly through ducts, even while you sleep. Secretion increases when you eat, because saliva is essential to moisten food and initiate the chemical breakdown of carbohydrates. In addition, the buccal glands in the cheeks, palatal glands in the palate, and lingual glands in the tongue help ensure that all areas of the mouth are supplied with adequate saliva. The Major Salivary Glands Outside the oral mucosa are three pairs of major salivary glands, which secrete the majority of saliva into ducts that open into the mouth: • The submandibular glands, which are in the floor of the mouth, secrete saliva into the mouth through the submandibular ducts. They secrete saliva into the mouth through the parotid duct, which is located near the second upper molar tooth (Figure 23. Perhaps the most important ingredient in saliva from the perspective of digestion is the enzyme salivary amylase, which initiates the breakdown of carbohydrates. Food does not spend enough time in the mouth to allow all the carbohydrates to break down, but salivary amylase continues acting until it is inactivated by stomach acids. Salivary mucus helps lubricate food, facilitating movement in the mouth, bolus formation, and swallowing. Saliva contains immunoglobulin A, which prevents microbes from penetrating the epithelium, and lysozyme, which makes saliva antimicrobial. Saliva also contains epidermal growth factor, which might have given rise to the adage “a mother’s kiss can heal a wound. The submandibular glands have cells similar to those of the parotid glands, as well as mucus-secreting cells. Therefore, saliva secreted by the submandibular glands also contains amylase but in a liquid thickened with mucus. The sublingual glands contain mostly mucous cells, and they secrete the thickest saliva with the least amount of salivary amylase. Mumps manifests by enlargement and inflammation of the parotid glands, causing a characteristic swelling between the ears and the jaw. Symptoms include fever and throat pain, which can be severe when swallowing acidic substances such as orange juice. In about one-third of men who are past puberty, mumps also causes testicular inflammation, typically affecting only one testis and rarely resulting in sterility. With the increasing use and effectiveness of mumps vaccines, the incidence of mumps has decreased dramatically. In the absence of food, parasympathetic stimulation keeps saliva flowing at just the right level for comfort as you speak, swallow, sleep, and generally go about life. Over-salivation can occur, for example, if you are stimulated by the smell of food, but that food is not available for you to eat. During times of stress, such as before speaking in public, sympathetic stimulation takes over, reducing salivation and producing the symptom of dry mouth often associated with anxiety. When you are dehydrated, salivation is reduced, causing the mouth to feel dry and prompting you to take action to quench your thirst. You might notice whether reading about food and salivation right now has had any effect on your production of saliva. Food contains chemicals that stimulate taste receptors on the tongue, which send impulses to the superior and inferior salivatory nuclei in the brain stem. These two nuclei then send back parasympathetic impulses through fibers in the glossopharyngeal and facial nerves, which stimulate salivation. Even after you swallow food, salivation is increased to cleanse the mouth and to water down and neutralize any irritating chemical remnants, such as that hot sauce in your burrito. The Teeth The teeth, or dentes (singular = dens), are organs similar to bones that you use to tear, grind, and otherwise mechanically break down food. Types of Teeth During the course of your lifetime, you have two sets of teeth (one set of teeth is a dentition). The third members of each set of three molars, top and bottom, are commonly referred to as the wisdom teeth, because their eruption is commonly delayed until early adulthood. Anatomy of a Tooth The teeth are secured in the alveolar processes (sockets) of the maxilla and the mandible. Gingivae (commonly called the gums) are soft tissues that line the alveolar processes and surround the necks of the teeth. The two main parts of a tooth are the crown, which is the portion projecting above the gum line, and the root, which is embedded within the maxilla and mandible. Both parts contain an inner pulp cavity, containing loose connective tissue through which run nerves and blood vessels. In the crown of each tooth, the dentin is covered by an outer layer of enamel, the hardest substance in the body (Figure 23. Although enamel protects the underlying dentin and pulp cavity, it is still nonetheless susceptible to mechanical and chemical erosion, or what is known as tooth decay. The most common form, dental caries (cavities) develops when colonies of bacteria feeding on sugars in the mouth release acids that cause soft tissue inflammation and degradation of the calcium crystals of the enamel. Digestive Functions of the Mouth Structure Action Outcome Lips and Confine food Food is chewed evenly during mastication cheeks between teeth Moisten and lubricate the lining of the mouth and pharynx Moisten, soften, and dissolve food Salivary Secrete saliva glands Clean the mouth and teeth Salivary amylase breaks down starch Manipulate food for chewing Tongue’s Move tongue extrinsic sideways, and in Shape food into a bolus muscles and out Manipulate food for swallowing Tongue’s Change tongue Manipulate food for swallowing intrinsic shape muscles Sense food in Nerve impulses from taste buds are conducted to salivary nuclei in the Taste buds mouth and sense brain stem and then to salivary glands, stimulating saliva secretion taste Activated in the stomach Lingual Secrete lingual glands lipase Break down triglycerides into fatty acids and diglycerides Shred and crush Break down solid food into smaller particles for deglutition Teeth food Table 23. It receives food and air from the mouth, and air from the 1104 Chapter 23 | The Digestive System nasal cavities. A short tube of skeletal muscle lined with a mucous membrane, the pharynx runs from the posterior oral and nasal cavities to the opening of the esophagus and larynx. The other two subdivisions, the oropharynx and the laryngopharynx, are used for both breathing and digestion. The oropharynx begins inferior to the nasopharynx and is continuous below with the laryngopharynx (Figure 23.
This voltage would actually be much lower except for the + + contributions of some important proteins in the membrane generic penegra 50 mg with amex. Leakage channels allow Na to slowly move into the cell or K + + to slowly move out buy penegra 100 mg lowest price, and the Na /K pump restores them generic 100mg penegra mastercard. The Action Potential Resting membrane potential describes the steady state of the cell, which is a dynamic process that is balanced by ion leakage and ion pumping. Because the concentration of Na is higher outside the cell than inside the cell by a factor of 10, ions will rush into the cell that are driven largely by the concentration gradient. Because sodium is a positively charged ion, it will change the relative voltage immediately inside the cell relative to immediately outside. The resting potential is the state of the membrane at a voltage of -70 mV, so the sodium cation entering the cell will cause it to become less negative. The electrical gradient also plays a role, as negative proteins below the membrane attract the sodium ion. These channels are 528 Chapter 12 | The Nervous System and Nervous Tissue + + specific for the potassium ion. As K starts to leave the cell, taking a positive charge with it, the membrane potential begins to move back toward its resting voltage. This is called repolarization, meaning that the membrane voltage moves back toward the -70 mV value of the resting membrane potential. Repolarization returns the membrane potential to the -70 mV value that indicates the resting potential, but it actually overshoots that value. Potassium ions reach equilibrium when the membrane voltage is below -70 mV, so a period of + + hyperpolarization occurs while the K channels are open. What has been described here is the action potential, which is presented as a graph of voltage over time in Figure 12. The change in the membrane voltage from -70 mV at rest to +30 mV at the end of depolarization is a 100-mV change. The change seen in the action potential is one or two orders of magnitude less than the charge in these batteries. What happens across the membrane of an electrically active cell is a dynamic process that is hard to visualize with static images or through text descriptions. The membrane potential will stay at the resting voltage until something This OpenStax book is available for free at http://cnx. A ligand-gated Na channel will open when a neurotransmitter binds + to it and a mechanically gated Na channel will open when a physical stimulus affects a sensory receptor (like pressure applied to the skin compresses a touch receptor). Whether it is a neurotransmitter binding to its receptor protein or a sensory stimulus activating a sensory receptor cell, some stimulus gets the process started. The channels that start depolarizing the membrane because of a stimulus help the cell to depolarize from -70 mV to -55 + mV. Any depolarization that does not change the membrane potential to -55 mV or higher will not reach threshold and thus will not result in an action potential. Also, any stimulus that depolarizes the membrane to -55 mV or beyond will cause a large number of channels to open and an action potential will be initiated. Because of the threshold, the action potential can be likened to a digital event—it either happens or it does not. If depolarization reaches -55 mV, then the action potential + continues and runs all the way to +30 mV, at which K causes repolarization, including the hyperpolarizing overshoot. Also, those changes are the same for every action potential, which means that once the threshold is reached, the exact same thing happens. A stronger stimulus, which might depolarize the membrane well past threshold, will not make a “bigger” action potential. All action potentials peak at the same voltage (+30 mV), so one action potential is not bigger than another. Stronger stimuli will initiate multiple action potentials more quickly, but the individual signals are not bigger. Thus, for example, you will not feel a greater sensation of pain, or have a stronger muscle contraction, because of the size of the action potential because they are not different sizes. As we have seen, the depolarization and repolarization of an action potential are dependent on two types of channels (the + + + voltage-gated Na channel and the voltage-gated K channel). The other gate is the inactivation gate, which closes after a specific period of time—on the order of a fraction of a millisecond. However, when the threshold is reached, the activation gate opens, allowing + Na to rush into the cell. After that, the inactivation gate re-opens, making the channel ready to start the whole process over again. It might take a fraction of a millisecond for the channel to open + + once that voltage has been reached. The timing of this coincides exactly with when the Na flow peaks, so voltage-gated K + channels open just as the voltage-gated Na channels are being inactivated. As the membrane potential repolarizes and the voltage passes -50 mV again, the channel closes—again, with a little delay. Potassium continues to leave the cell for a short while and the membrane potential becomes more negative, resulting in the hyperpolarizing overshoot. Then the channel closes again and the membrane can return to the resting potential because of the ongoing activity of the non-gated channels + + and the Na /K pump. There are two phases of the refractory period: the absolute refractory period and the relative refractory period. Once that channel is back to its resting conformation (less than -55 mV), a new action potential could be started, but only by a stronger stimulus than the one that + initiated the current action potential. Because that ion is rushing out, any + Na that tries to enter will not depolarize the cell, but will only keep the cell from hyperpolarizing. Propagation of the Action Potential The action potential is initiated at the beginning of the axon, at what is called the initial segment. There is a high density of + voltage-gated Na channels so that rapid depolarization can take place here. Going down the length of the axon, the action + potential is propagated because more voltage-gated Na channels are opened as the depolarization spreads. This spreading + + occurs because Na enters through the channel and moves along the inside of the cell membrane. As the Na moves, or flows, a short distance along the cell membrane, its positive charge depolarizes a little more of the cell membrane. As that + depolarization spreads, new voltage-gated Na channels open and more ions rush into the cell, spreading the depolarization a little farther. The action potential must propagate toward the axon terminals; as a result, the polarity of the neuron is maintained, as mentioned above. Sodium ions that enter the cell at the initial segment start to spread along the length of the axon + segment, but there are no voltage-gated Na channels until the first node of Ranvier.
M-protein vaccines in the era of molecular biology Although our knowledge of the structure and function of M-protein has advanced considerably in recent years (11–15) discount penegra 50mg with mastercard, M-protein pre- parations used in vaccines are still not free of epitopes that elicit immunological cross-reactivity with other human tissues purchase penegra 100 mg otc. Antibodies against M-proteins penegra 50 mg mastercard, for example, cross-react with alpha-helical human proteins, such as tropomyosin, myosin and vimentin. Primary struc- ture data have revealed that M-proteins of rheumatogenic streptococ- cal serotypes, such as serotypes 5, 6, 18 and 19, share similar sequences within their B-repeats, and it is likely that such sequences are responsible for eliciting antibodies that cross-react with epitopes in the heart, brain and joints (16). Most of the cross-reactive M- protein epitopes appear to be located in the B-repeats, the A-B ﬂanking regions, or the B-C ﬂanking regions, all of which are some distance from the type-speciﬁc N-terminal epitopes (16–18). In contrast, antibodies raised against synthetic N-terminal peptides that correspond to the hypervariable portions of M-protein serotypes 5, 6 and 24 are opsonic, but do not cross-react with human tissue (17– 19). Further studies have shown that peptide fragments of M- 106 proteins, incorporated into multivalent constructs as hybrid proteins or as individual peptides linked in tandem to unrelated carrier pro- teins, elicited opsonic and mouse-protective antibodies against mul- tiple serotypes, but did not evoke heart-reactive antibodies (20, 21). These estimates were based on sero- type distribution data from economically developed western coun- tries, and such a vaccine might need to be reconstituted, based on prevalent local strains. Current studies are directed toward utilizing commensal gram-positive bacteria as vaccine vectors (22–23). One of these is C5a peptidase, an enzyme that cleaves the human chemotactic factor, C5a, and thus interferes with the inﬂux of polymorphonuclear neutrophils at the sites of inﬂammation (24). Intranasal immunization of mice with a defective form of the streptococcal C5a peptidase reduced the colo- nizing potential of several different streptococcal M-serotypes (25). A second potential vaccine target is streptococcal pyrogenic exotoxin B (SpeB), a cysteine protease that is present in virtually all group A streptococci. Mice passively or actively immunized with the cysteine protease lived longer than non-immunized animals after infection with group A streptococci (26). Epidemiological considerations Once a safe and effective streptococcal vaccine is available many practical issues would need to be addressed. Other issues, such as cost, route of administration, number and frequency of required doses, potential side-effects, stability of the material under ﬁeld conditions, and dura- bility of immunity, would all inﬂuence the usefulness of any vaccine. The most promising approaches are M-protein-based, including those using multivalent type-speciﬁc vaccines, and those directed at non-type-speciﬁc, highly conserved portions of the molecule. Success in developing vaccines may be achieved in the next 5–10 years, but this success would have to contend with important questions about the safest, most economical and most efﬁcacious way in which to employ them, as well as their cost-effectiveness in a variety of epidemilogic and socio-economic conditions. A review of past attempts and present concepts of producing streptococcal immunity in humans. Intravenous vaccination with hemolytic streptococci: its inﬂuence on the incidence of rheumatic fever in children. Persistence of type-speciﬁc antibodies in man following infection with group A streptococci. Epitopes of group A streptococcal M protein shared with antigens of articular cartilage and synovium. Rheumatic fever: a model for the pathological consequences of microbial-host mimicry. Streptococcal M protein: alpha-helical coiled-coil structure and arrangement on the cell surface. Alternate complement pathway activation by group A streptococci: role of M-protein. Inhibition of alternative complement pathway opsonization by group A streptococcal M protein. Streptococcal infections: clinical aspects, microbiology, and molecular pathogenesis. Type-speciﬁc immunogenicity of a chemically synthesized peptide fragment of type 5 streptococcal M protein. Multivalent group A streptococcal vaccine designed to optimize the immunogenicity of six tandem M protein fragments. Protection against streptococcal pharyngeal colonization with a vaccinia:M protein recombinant. Intranasal immunization with C5a peptidase prevents nasopharyngeal colonization of mice by the group A Streptococcus. Vaccination with streptococcal extracellular cysteine protease (interleukin-1 beta convertase) protects mice against challenge with heterologous group A streptococci. Acute rheumatic fever in Auckland, New Zealand: spectrum of associated group A streptococci different from expected. Adding to the burden on health systems of developing countries are the costs of outside referrals that are often required during the course of treatment. The socioeconomic costs were also borne by the parents of the patients, with 22% exhibiting absenteeism from work, and about 5% losing their jobs. As a programme design strategy, it is advisable to attempt small-scale pilot programmes before initiating large-scale national control programmes, as the lessons learnt from pilot schemes can, in addition to many other beneﬁts, prevent the waste of scarce resources (2, 7). These studies emphasize that national prevention programmes based on secondary prophylaxis have the potential for considerable cost savings, which could be used to improve the spread and gains of a programme. Evidence has been presented from a simulation study suggested that the most cost-effective strat- egy was to treat all pharyngitis patients with penicillin (particularly those within an at-risk group), without a strict policy of waiting for the disease to be conﬁrmed by bacterial culture (7, 11). However, this approach has not been conﬁrmed and cannot be advocated until more thorough studies are carried out. In hospital settings where facilities are available, the “culture and treat” strategy has been shown to be cost-effective (12). Analysis of costs of acute rheumatic fever and rheumatic heart disease in Auckland. Analysis of the cost-effectiveness of pharyngitis management and acute rheumatic fever prevention. It is important to implement such programmes through the existing national infrastructure of the ministry of health and the ministry of education without building a new administrative mechanism. This would minimize additional costs and prevent unsus- tainable monolithic programmes (2, 3, 6, 11, 12). Based upon previous experience (1, 2, 11, 12), planning and implementation of national programmes should be based on the following principles: • There should be a strong commitment at policy level, particularly in the ministries of health and education. A central or a local referral or registration centre should be established in participating areas. Attention should be given to patients who have difﬁculties in adhering to long-term secondary prophylaxis regimes, or who drop out of the prevention regime (i. Primary prevention activities Primary prevention is based on the early detection, correct diagnosis and appropriate treatment of individual patients with Group A strep- tococcal pharyngitis. Such programmes need to part of the routine medical care available and should be integrated in to the existing health infrastructure. Health education to the public, teachers and health personnel would enhance the impact of a primary prevention programme. Health education activities Health education activities should address both primary and second- ary prevention. The activities may be organized by trained doctors, nurses or teachers and should be directed at the public, teachers and parents of school-age children. Health education activities should focus on the importance of recognizing and reporting sore throats early; on methods that minimize and avoid the spread of infection; on the beneﬁts of treating sore throats properly; and on the importance of complying with prescribed treatment regimes. Health messages could be transmitted to parents indirectly by targeting schoolchildren.
While ad- vancing the needle penegra 100mg on-line, the anesthesiologist maintains pres- sure on the syringe in order to sense the resistance of Reproduced with permission from Astra Pharma Inc effective penegra 100mg. The epidural space is a “potential space” such that when it is entered Figure 13 Insertion of epidural catheter with the needle generic penegra 50 mg with mastercard, a sudden loss of resistance is detected. The syringe is then removed so that a catheter can be threaded through the needle into the epidural space (Figure 13), after which the needle is removed. Inserting an epidural through tattooed skin is undesir- able as it may bring a plug of ink into the epidural space, the consequences of which are not known. In this case, the anesthesiologist is able to locate a small Reproduced with permission from Astra Pharma Inc. Bupivacaine, while second challenge is performing a technical procedure possessing a slower onset of effect, has a longer dura- in a patient who is in active labour. The dermatomal level of block is tested esthesiologist pauses while the patient is having con- by pinprick or ice cube (Figure 14). The patient is able to do an excellent job of re- 20-30 minutes for an adequate epidural block to take maining still, which is quite important during this deli- effect. The higher the surgi- carefully for the moment of the “loss of resistance”, cal site is, the higher the block must be. Table 10 de- when the gentle pressure on the hub of the syringe ﬁ- scribes the dermatomal level of block required for some nally gives way, as the needle has entered the “poten- of the more common surgical procedures which apply tial” space that is the epidural space. Late complications are related to needle and catheter insertion, and include nerve injury, epidural abcess or hematoma, and post-dural puncture head- ache (if the dura is accidentally punctured). Because the dura is a tough membrane, a deﬁnite “pop” is often felt as the needle passes through into the intrathecal space. However, if The contraindications to spinal anesthesia are listed in the block dissipates prior to the end of the procedure Table 11. Through- procedures on the distal upper extremity (below the el- out their journey to the axilla, the nerve roots merge bow). After cannulating a vein distal to the surgi- roots travel through the intervertebral foramina and cal site, the operative arm is elevated and an elastic ban- emerge between the anterior and middle scalene mus- dage is applied to promote venous drainage. As they exit the 50 ml of dilute lidocaine (without epinephrine) is then axilla, the plexus divides one ﬁnal time to form the axil- injected slowly into the cannula in the operative arm. The brachial plexus block provides anesthesia tem to the interstitium provides surgical anesthesia for virtually any type of upper extremity surgery. If the surgical procedure lasts less than 20 rect needle placement is ensured through the use of ei- minutes then one must wait until 20 minutes has ther ultrasound or nerve stimulator. The supraclavicu- lar and interscalene blocks pose the additional risks of There are many potential complications of a brachial pneumothorax, phrenic nerve block and recurrent la- plexus block. Intrathecal injection Figure 17 Brachial plexus: roots, trunks, divisions, cords is a rare complication of interscalene block. Drugs Used in the drugs, there is an ever-increasing variety of tech- agents (both intravenous and inhaled) at our dis- Maintenance of Anesthesia niques used to provide general anesthesia. Emergence techniques strive to achieve the following goals, speciﬁc effects such as analgesia or muscle relaxa- known as the “Four A’s of Anesthesia”: tion and therefore can be used to achieve the de- • Lack of Awareness: unconsciousness. The practice of using combinations of agents, each for a speciﬁc purpose, is what is termed • Analgesia: the abolition of the subconscious re- “balanced anesthesia”. An example of a balanced actions to pain, including somatic reﬂexes technique would be the use of propofol for induc- (movement or withdrawal) and autonomic re- tion of anesthesia; the administration of des- ﬂexes (hypertension, tachycardia, sweating ﬂurane and nitrous oxide for maintenance of un- and tearing). Be- • improved hemodynamic stability cause the above-described goals were achieved by a progressive depression of the central nerv- • more effective muscle relaxation ous system rather than by any direct or speciﬁc 56 • more rapid return of respiratory function, conscious- Induction ness and airway control following the completion of The goal of the induction phase of anesthesia is to in- the procedure duce unconsciousness in a fashion which is pleasant, • provision of post-operative analgesia with appropri- rapid and maintains hemodynamic stability. If the anes- ate timing and dosing of opioids administered intra- thetic plan includes control of the airway and ventila- operatively tion then the induction phase also aims to achieve mus- cle relaxation to facilitate endotracheal intubation. A balanced technique is still the most common tech- nique used for the provision of general anesthesia. Anesthesia can be induced by having the patient However, with the development of short-acting intrave- breathe increasing concentrations of inhaled gases by nous agents such as propofol and remifentanil, the mask. While there are settings where this is the desired above-described goals of general anesthesia can be at- technique, it tends to be slow and can be unpleasant. Understanding the dynamics of induction mined, one can proceed with administering the anes- requires a grasp of the essential pharmacology of these thetic. A general anesthetic consists of four phases: in- agents; the reader can do so by touching the hyperlink duction, maintenance, emergence and recovery. Rapid Sequence Induction Although regurgitation and aspiration are potential complications of any anesthetic, there are factors which place some patients at higher risk (Table 7). However, even a prolonged period of fasting does not guarantee an “empty stomach” if gastric emptying is delayed. Ex- 57 amples of conditions which impair gastric emptying in- The purpose of pre-oxygenation is to lessen the risk of clude diabetes, trauma, recent opioid administration hypoxemia occurring during the apneic period after in- and bowel obstruction. Traditionally teaching is that for aspiration, the time between inducing anesthesia the Sellick maneuver provides occlusion of the esopha- and securing the airway with a cuffed endotracheal gus between the cricoid cartilage (a complete circumfer- tube must be minimized. Such a technique is termed a ential cartilage) and the cervical vertebrae thus mini- “rapid sequence induction”. A rapid sequence induction is performed as follows: Succinylcholine Succinylcholine (Sch), a depolarizing muscle relaxant, 1. Suction apparatus is checked and kept readily avail- is a very useful and very powerful drug; the anesthesi- able. Pre-oxygenation of patient with 100% oxygen for 3-5 tions of Sch in order to avoid causing harm or death. Neuromuscular block- agent followed immediately by intubating dose of ade (paralysis) develops because a depolarized post- depolarizing muscle relaxant (succinylcholine). Succinylcholine has effects on almost every organ sys- tem, most of them being secondary to the depolariza- 5. Intubation of trachea, cuff inﬂation and veriﬁcation tion and subsequent contraction of skeletal muscle. A or in patients with renal failure, for whom even a small further consideration is the length of the procedure and rise in potassium could have critical implications. These agents are described later nal cord injury or stroke), amyotrophic lateral sclerosis, in this chapter. Some types of surgical procedures such as Caesarian section, cardiac surgery 59 and trauma surgery pose a higher risk of awareness be- prone or kidney position is used. In the semi-sitting po- cause of the nature of the anesthetic given for those pro- sition, venous pooling in the legs has a similar effect. It may be prudent to warn such patients of the Very occasionally, surgery is performed in the sitting risk pre-operatively. Intra-operatively, care should be taken to ensure deliv- ery of adequate amounts of hypnotic drugs such as in- The airway may become obstructed or dislodged while haled agents, propofol, benzodiazepines or ketamine. The prone, trende- Opioids alone provide very little hypnosis and muscle lenburg and lithotomy positions may cause an upward relaxants provide none whatsoever! Other factors such as prolonged ingly, the overwhelming majority of cases of awareness surgery, hypothermia, hypotension, obesity and diabe- have been reported in paralyzed patients. De- superﬁciality, is at risk of compression in almost any po- pending on the procedure, the patient may be placed in sition.
Potential post op problems include respiratory depression (excess analgesia) purchase 50mg penegra fast delivery, respiratory difficulty due to splinting (inadequate analgesia) cheap penegra 100mg mastercard, pain control (difficult) discount penegra 100 mg without prescription, and fluid balance. There is typically a fair bit of blood loss and there can be significant swelling of the involved tissues. The most important things to monitor are the status of the airway and continued bleeding. Tracheostomy--Airway, sedation, ventilation The most critical issues for the fresh trach is not losing it. Hence, patients who are “wild” should be adequately sedated, especially if they were trached because they were impossible to intubate. There are “stay sutures” which are at the base of the incision and can be held up to help provide a “tract” should the trach tube come out. Craniosynostosis--Blood Loss During craniectomy for craniosynostosis one or more of the sutures of the cranium are cut. You should be aware of whether the patient is syndromic or not (those with a “syndrome” typically have more sutures in need of repair, and might well have other problems), and the extent of the repair. Because of the large blood loss, they typically receive quite a bit of fluid intra-operatively as well as post-operatively. Each member of the team brings unique knowledge and perspective to the care of the patient and recognizing and integrating all members of the team in the ongoing care of the patient is essential in providing optimal care for these patients. The presence of trainees from medicine, nursing, respiratory therapy, or other disciplines adds to the size and complexity of the team caring for the patient, and the roles and responsibilities of these individuals must be explicitly acknowledged. Perioperative care encompasses both pre and post operative care of the patient with congenital heart disease. Although many infants and children with congenital heart defects are managed as outpatients until their repairs, some infants or older children with severely abnormal physiology require stabilization and critical care prior to surgery. Many of the basic principles of cardiac intensive care apply to both pre and post operative care and will be considered in this chapter. In addition to supportive care and stabilization, pre operative management includes thorough evaluation of the anatomy and physiology of the heart and the physiologic status of the patient as a whole so that appropriately planned and timed surgery can take place. Basic principles of pediatric critical medical and nursing care remain relevant in the pediatric congenital cardiac patient. Pediatric cardiac patients are cared for in specialized cardiac intensive care units and in multidisciplinary intensive care units. There is some data that institutions that perform more surgeries have improved outcomes (info here—based on surgeon, unit, hospital?? Regardless of the focus of the unit, a commitment to ongoing education and training, as well as a collaborative and supportive environment is essential. We feel strongly that a unit dedicated to the care of infants and children is best able to care for these patients (down on the adult units caring for kids). Oxygen delivery is therefore primarily dependent on systemic cardiac output, - 58 - hemoglobin concentration, and oxygen saturation. Stroke volume is in turn dependent on preload, afterload, and myocardial contractility. Both pulmonary blood flow (Qp) and systemic blood flow (Qs) are determined by these fundamental forces. In the patient with two ventricles, ventricular interdependence, or the affect of one ventricle on the other, may play a role in pulmonary or systemic blood flow. In some situations, including the post operative state, the pericardium and restriction due to the pericardial space may also play a role in ventricular output. When evaluating the loading conditions of the heart and myocardial contractility, it is important to consider the two ventricles independently as well as their affect on one another. In previously healthy pediatric patients without heart disease, right atrial filling pressures are commonly assumed to reflect the loading conditions of the left as well as the right ventricle. Pre-existing lesions and the affects of surgery may affect the two ventricles differently. For example, the presence of a right ventricular outflow tract obstruction will lead to hypertrophy of the right ventricle. That right ventricle will be non-compliant, and the right atrial pressure may therefore not accurately reflect the adequacy of left ventricular filling. Oxygen content (CaO2) is primarily a function of hemoglobin concentration and arterial oxygen saturation. Thus, patients who are cyanotic can achieve adequate oxygen delivery by maintaining a high hemoglobin concentration. Arterial oxygen saturation is commonly affected by inspired oxygen content, by mixed venous oxygen content of blood, by pulmonary abnormalities, and by the presence of a R to L intracardiac shunt. Arterial oxygen content in the patient with a single ventricle and parallel pulmonary and systemic circulations will depend on the relative balance between the circulations as well. In the patient with intracardiac shunt or the single ventricle patient, arterial oxygen content is also affected by the relative resistances of the pulmonary and systemic circuits, as this determines how much blood flows through the lungs relative to the systemic output. Low mixed venous oxygen content contributes to desaturation and suggests increased oxygen extraction due to inadequate oxygen delivery, which in turn is either due to inadequate systemic cardiac output or inadequate hemoglobin concentration. A thorough understanding of these fundamental principles of cardiac output and oxygen delivery is essential for the perioperative care of the patient with congenital heart disease. General Principles of Anatomy and Pathophysiology Affecting Pre-operative and Post- operative Management An understanding of the anatomy and pathophysiology of the congenital cardiac lesion under consideration allows one to determine the pre-operative care or resuscitation needed and to predict the expected post-operative recovery. Acyanotic Heart Disease Children with acyanotic heart disease may have one (or more) of three basic defects: 1) left-to-right shunts (e. These lesions may lead to decreased systemic oxygen delivery by causing maldistribution of flow with excessive pulmonary blood flow (Qp) and diminished systemic blood flow (Qs) (Qp/Qs >1), by impairing oxygenation of blood in the lungs caused by increased intra and extravascular lung water, and decreasing ejection of blood from the systemic ventricle. Maldistribution of Flow: Qp/Qs >1 In infants with left-to-right shunts, pulmonary blood flow (Qp) increases as pulmonary vascular resistance (Rp) decreases from the high levels present perinatally. As pulmonary flow increases, left ventricular volume overload may occur with cardiac failure, decreased systemic output, pulmonary congestion and edema. If pulmonary pressures exceed systemic pressures, right to left shunting predominates and the patient becomes cyanotic. Depending on the type and size of the lesion, pulmonary over circulation that remains uncorrected may lead to pulmonary vascular obstructive disease as early as 6 months of age. Pulmonary over circulation can lead to congestive heart failure through several mechanisms. Increased Qp leads to left (systemic) ventricular volume overload and raises left ventricular end diastolic, left atrial, and pulmonary venous pressures. The increases in pulmonary artery and pulmonary venous pressures raise the pulmonary hydrostatic pressure gradient and these promote transudation of fluid into the interstitial space and ultimately lead to alveolar edema. Right ventricular end diastolic pressure, and hence, right atrial and systemic venous pressures, are also elevated.
It occurs in less than one in ten thousand pregnancies discount penegra 50mg without a prescription, and is an autoimmune reaction that may be aggravated by oestrogen buy penegra 100mg with mastercard. Patients develop extremely itchy trusted 50 mg penegra, fluid filled, scattered small lumps on the body, particularly the belly, sides of the trunk, palms and soles. The prognosis is good and the condition usually does not affect the baby, but it tends to recur in subsequent pregnancies. Labour can be induced in a number of ways, including rupturing the membranes that surround the baby through the vagina, stimulating the cervix, by tablets, vaginal gel (eg. Using these methods, doctors can control the rate of labour quite accurately to ensure that there are no problems for either mother or baby. There is some evidence that labour can be induced in the last week or two of pregnancy by an orgasm after sexual intercourse or by the constant stimulation of the nipples. Iron is used as a medication in tablet, capsule, mixture or injection forms to treat or prevent iron deficiency and some types of anaemia. Pregnant women are at risk of iron deficiency because the developing baby to build muscle and blood cells. In medication, it is not pure iron that is used, but various salts (compounds) of iron such as ferrous gluconate, ferrous phosphate, ferrous sulfate, ferric ammonium citrate, ferric pyrophosphate, ferrous fumarate and iron amino acid chelate. Iron is absorbed from the gut at a set rate, and using higher doses is unlikely to have any clinical effect. Iron should not be used if suffering from haemochromatosis, ulcerative colitis, ileostomy or colostomy, anaemia not due to iron deficiency. Iron supplements interact with many other drugs including tetracycline, penicillamine, antacids, calcium, methyldopa, levodopa, chloramphenicol, cimetidine, thyroxine, phenytoin, cholestyramine and St. This is called a Ker incision and causes fewer long-term problems to the woman than any other form of incision into the uterus as it heals very well. Every few hours you have Branxton-Hicks contractions that can be quite uncomfortable and sometimes wake you at night, but they always fade away. Your back aches, and you are going to the toilet every hour because your bladder has nowhere to expand. Suddenly you notice that you have lost some bloodstained fluid through the vagina, and the contractions are worse than usual. You have passed the mucus plug that seals the cervix during pregnancy, and if a lot of fluid is lost, you may have ruptured the membranes around the baby as well. When you find that two contractions have occurred only five to seven minutes apart, it is time to be taken to hospital or the birthing centre. This stage will last for about 12 hours with a first pregnancy, but will be much shorter (4 to 8 hours) with subsequent pregnancies. By the time the obstetrician calls in to see how you are progressing, the contractions are occurring every three or four minutes. The obstetrician examines you internally to check how far the cervix (the opening into the womb) has opened. A fully dilated cervix is about 10 cm in diameter, and you may hear the doctors and nurses discussing the cervix dilation and measurement. In a typical hospital delivery room, white drapes hide bulky pieces of equipment, there are large lights on the ceiling, shiny sinks on one wall, and often a cheerful baby poster above them. The breathing exercises you were taught at the antenatal classes should prove remarkably effective in helping you with the more severe contractions. Even so, the combined backache and sharp stabs of pain may need to be relieved by an injection offered by the nurse. Your cervix will be fully dilated by this stage, and you are now entering the second stage of labour, which will last from only a few minutes to 60 minutes or more. The contractions are much more intense than before, but you should push only at the time of a contraction, as pushing at other times is wasted effort. Another push, and another, and another, and then a sudden sweeping, elating relief, followed by a healthy cry from your new baby. A minute or so after the baby is born the umbilical cord, which has been the lifeline between you and the baby for the last nine months, is clamped and cut. About five minutes after the baby is born, the doctor will urge you to push again and help to expel the placenta (afterbirth). Labour commences when the cervix starts to dilate and finishes with delivery of the baby and placenta. The exact triggers that start the labour of pregnancy are unknown, but the hormones responsible come from the pituitary gland in the brain. There is some evidence that labour can be induced in the last week or two of pregnancy by an orgasm after sexual intercourse or by the constant stimulation of the nipples. The vagina (birth canal) is a curved cylinder and the baby’s head must move through various positions in order to pass through it. This is followed by flexion of the head, descent of the head, internal rotation, extension of the neck, external rotation and finally expulsion. These movements will differ if the baby’s head is in a different position to the normal one of coming out with the back of the head at the front of the mother. A line between the spines on the ischial bone, which can be felt by a doctor when examining the vagina, is station zero. It last on average 14 hours in a woman having her first baby and seven hours in a woman who has already had a baby. In second stage the baby’s head descends further into the pelvis and lasts until the birth of the baby with forceful contractions of the uterus lasting from 60 to 90 seconds every two to five minutes. The patient develops an almost unbearable urge to push, which should be resisted until it can be timed with a contraction. The second stage lasts on average one hour in a first time mother and twenty minutes in a second time mother. The third stage of labour lasts from the birth of the baby to the expulsion of the placenta (afterbirth), which takes ten to fifteen minutes. The baby moves down through the vagina and is expelled from the uterus by the force exerted by the powerful muscle contractions in the uterus, and is assisted by contractions of the muscles in the wall of the abdomen and in the diaphragm as the mother voluntarily pushes. After the baby is delivered further contractions of the uterus over the next few minutes cause the placenta to separate from the wall of the uterus and be expelled. The muscles of the uterus may not produce sufficiently strong contractions, or may not contract regularly. Some women have uncoordinated contractions, which cause different parts of the uterine muscle to contract at different times. This can be caused by the baby having a large head, having the head twisted in an awkward position, or having an abnormal part of the baby presenting (eg. Sometimes forceps can be used to assist these situations, but often a Caesarean section is necessary for the wellbeing of the baby. In some women, the cervix fails to dilate and remains as a thick fibrous ring that resists any progress of the baby down the birth canal. In an emergency the cervix may be cut, but in most cases doctors would again prefer to perform a Caesarean section. It involves four steps:- - gentle controlled delivery in a quiet dark room - avoiding any pulling on the baby’s head - avoiding over stimulating the baby in any way - encouraging immediate bonding between mother and baby and breastfeeding. The presence of the father in the delivery room, massaging of the baby’s back after birth, not cutting the umbilical cord until it stops pulsating, and gentle bathing in warm water by the father may be other factors.
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