Minimally Invasive Surgery


   1.   In the past three decades, minimally invasive surgery has emerged as a mainstream technique in infants and children, even largely supplanting many commonly performed open operations.


   2.   Potential advantages of a laparoscopic approach are smaller incisions with improved cosmesis, less perioperative pain, lower infection risk, and a decreased length of hospital stay.


   3.   Laparoscopic surgery has many physiologic effects on the human body. The effects of pneumoperitoneum result in increases of intra-abdominal pressure (IAP) up to 20 cm H2O and are accompanied by increases of central venous pressure (CVP), intrathoracic pressure, and cardiac output. Greater increases of IAP to approximately 40 cm H2O are accompanied by decreases in CVP and cardiac output, with parallel changes in mean arterial pressure and moderate tachycardia.


   4.   Due to the carbon dioxide insufflation to create the pneumoperitoneum, hypercarbia may result in elevated endogenous catecholamines accompanied by vasoconstriction, increased CVP, and increased inotropic, chronotropic, and arrhythmogenic effects on the heart.


   5.   Anesthetic considerations for laparoscopic surgery include adequate upper body vascular access and possible intravascular monitoring. Prolonged laparoscopically-assisted procedures may have ongoing cardiopulmonary effects in the immediate perioperative period in patients with chronic medical conditions; such patients may require intensive care unit (ICU) support despite undergoing a procedure with less extensive tissue trauma or fewer surgical incisions.


   6.   Single-incision laparoscopic surgery (SILS) is a novel, minimally invasive approach using a single skin incision, commonly in the periumbilical location, instead of three to four laparoscopic ports. In comparison to standard laparoscopy, SILS offers improved cosmesis but postoperative pain is not reduced, likely because of extensive surgical manipulation of the fascial wall.


   7.   Natural orifice translumenal endoscopic surgery (NOTES) is another novel minimally-invasive surgical approach. It is currently still in the developmental stage with only a few pediatric cases performed, but it is considered a potential alternative to open or laparoscopic surgery in the future. Currently, the majority of human case reports are hybrid-NOTES procedures using laparoscopic ports for visualization, retraction, and technical assistance.



Minimally invasive surgery has rapidly emerged as a mainstream technique in infants and children, even largely supplanting many commonly performed open operations. As with conventional surgical techniques, the anesthetic care is dictated by age, coexisting conditions, and acuity of presenting medical condition; therefore, thorough preoperative evaluation and preparation for anesthesia is mandated. Additionally, the unique physiologic perturbations induced by the operating conditions required for minimally invasive techniques impose critical differences in anesthetic management. In the following sections, a brief background about the development of endoscopic surgery, the physiologic impact of minimally invasive surgery, and special anesthetic considerations will be outlined.


      I.   History and background


               A.   Minimally invasive surgery, although relatively new to pediatric procedures, has a long and interesting history.


                       1.   At the end of the 19th century, the use of endoscopy was limited to examination of the bladder, rectum, and pharynx.


                            a.   The development of a device to evaluate and intervene in body cavities previously only accessible by the scalpel is credited to a German physician, Philipp Bozzini (1).


                            b.   Consisting of a tube with an eyepiece, a candle for illumination, and a mirror to reflect the image, the image was of poor quality and the experience quite painful for the patient.


                       2.   In 1902, Georg Kelling, a German gastrointestinal surgeon, examined the peritoneal cavity of a dog using a cystoscope, and by 1910, had performed many successful laparoscopies on patients using the pneumoperitoneum technique (2).


                       3.   It was not until the early 1970s with the development of the Hopkins rod lens system and improved illumination that adequate optics were achieved and “peritoneoscopy” for infants and children was popularized by Stephen Gans and Berci (3).


                       4.   In 1981, Kurt Semm, a German gynecologist, performed the first laparoscopic procedure: a laparoscopic appendectomy.


                            a.   Following his lecture about his procedure, the president of the German Surgical Society wrote to the Board of Directors of the German Gynecological Society suggesting suspension of Semm from medical practice.


                            b.   Subsequently, Semm submitted a paper on laparoscopic appendectomy to the American Journal of Obstetrics and Gynecology, at first rejected as unacceptable for publication on the grounds that the technique reported on was “unethical,” but finally published in the journal Endoscopy (4,5).


                       5.   In 1985, Erich Muehe, a professor of surgery in Boeblingen, Germany, used Semm’s instruments and technique to laparoscopically remove the first gallbladder (6). It was not until the 1990s when laparoscopic surgery became an established, entrusted technique for many abdominal procedures. Now, countless endoscopic or minimally invasive surgeries have been performed in all of the major surgical specialties (Table 37.1).


TABLE 37.1  Minimally invasive surgical procedures




General surgery


    Appendectomy


    Cholecystectomy


    Inguinal hernia repair


    Ventral hernia repair


    Nissen fundoplication


    Splenectomy


    Adrenalectomy


    Donor nephrectomy


    Diagnostic laparoscopy


    Pectus excavatum repair


    Pyloromyotomy


    Laparoscopically-assisted colon resections


       Inflammatory bowel disease


       Crohn disease


       Ulcerative colitis


       Diverticulosis/diverticulitis


       Fistulas


       Colorectal cancer


       Pull-through procedures for Hirschsprung disease


Gynecologic surgery


    Colposcopy


    Endometrial ablation


    Hysteroscopy


    Laparoscopy


    Laparoscopic myomectomy


Thoracic surgery


    Thoracoscopic lobectomy


    Thoracoscopic sympathectomy


    Thoracoscopic release/anterior spinal fusion


    Nissen fundoplication


    Myotomy for achalasia


    Thymectomy for myasthenia gravis


    Pulmonary nodules


    Pneumothorax


    Thoracic outlet syndrome


    Empyema drainage


    Pleurodesis


Cardiovascular surgery


    Ligation of patent ductus arteriosus


Otolaryngology


    Functional endoscopic sinus surgery


Neurosurgery


    Endoscopic third ventriculostomy


    Endoscopic tumor biopsy


    Endoscopic cyst fenestration


Urology


    Concealed orchiopexy


    Nephrectomy (partial or total)


    Extravesical ureteral reimplantation


    Varicocelectomy


Orthopedic surgery


    Arthroscopically-assisted procedures


    Hip arthroscopy



                       6.   Benefits compared to conventional laparotomy include less pain; improved cosmesis; shorter hospital and recovery times; fewer adhesions; decreased blood loss; and decreased pulmonary, wound, and other infections.


                       7.   Moreover, as surgeons have become more proficient and equipment more sophisticated, the number and complexity of minimally invasive procedures performed in infants and children have increased.


     II.   Emerging and innovative surgical techniques


               A.   Traditional laparoscopy is usually carried out through three or more ports that are introduced through different skin incisions.


               B.   Single-incision laparoscopic surgery (SILS) is a novel minimally invasive approach: a single cutaneous incision, commonly in the periumbilical location, is created and a single access device with multiple ports or several single ports adjacent to each other may be placed to laparoscopically approach the abdominal cavity.


                       1.   SILS offers improved cosmesis, but postoperative pain is not reduced, likely because of extensive surgical manipulation of the fascial wall (7).


                       2.   A prospective randomized trial of 50 pediatric patients undergoing surgery for acute appendicitis compared SILS to conventional multiport laparoscopy.


                            a.   No significant difference in postoperative complications or hospital stay could be observed between the two techniques.


                            b.   Significantly shorter operating times and overall costs in pediatric patients undergoing appendectomy with the SILS approach were demonstrated in another study (8,9).


               C.   Natural orifice translumenal endoscopic surgery (NOTES) is another novel minimally-invasive surgical approach.


                       1.   It is currently a developing and experimental alternative to open or laparoscopic surgery (10).


                       2.   NOTES procedures are performed by entering the peritoneal cavity via an endoscopic translumenal approach through a natural orifice.


                            a.   To date, transgastric, transcolonic, transvaginal, and transurethral/transcystic approaches exist.


                            b.   Although NOTES is currently limited to a few academic and research institutions, increasing numbers of NOTES procedures have been performed in humans in the last years.


                            c.   This new concept is driven by the hypothesis that a translumenal approach is less painful than an abdominal wall incision.


                            d.   Potential benefits are considered to be fewer complications such as ileus, abdominal wall pain, hernias, and improved cosmetic outcomes.


                            e.   Better access to certain areas of the peritoneal cavity in specific patient populations (e.g., the obese) might prove to be advantageous with this new technique.


                       3.   So far, the NOTES approach has been largely studied in animal models.


                       4.   Case reports and series of human NOTES are increasing since the technique was introduced in 2004 (11).


                            a.   A case of successful treatment of pediatric gastroesophageal reflux disease using a transoral incisionless fundoplication procedure instead of the standard laparoscopic Nissen fundoplication has been reported (12).


                       5.   To detect complications and potential problems, early outcome databases such as the Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR) registry, the German National Notes Registry, and the Euro Notes Registry have been established by individual medical societies.


                       6.   As of today, only a small number of cases have been purely NOTES.


                            a.   The majority of human case reports are hybrid-NOTES procedures using laparoscopic ports for visualization, retraction, and technical assistance:


                            b.   For example, surgical treatment of Hirschsprung disease successfully combined a laparoscopic-assisted pull-through procedure with transrectal NOTES, minimizing the need for large transabdominal working port sites (13).


                            c.   Pig models show promising results for very delicate long-gap esophageal atresia repair combining laparoscopy and NOTES (14).




CLINICAL PEARL Occasional case reports of catastrophic cardiovascular collapse occurring during laparoscopy have been attributed to reflex-mediated bradycardia, hypercapnia, anoxia, decreased venous return and cardiac output, gas embolism, and a profound vagal response to peritoneal distension.


Pneumoperitoneum alone and together with head-down tilt may shift the endotracheal tube into a deeper position, thereby getting in contact with the carina resulting in airway irritation, possible coughing, or bronchospasm or the endotracheal tube may advance into a right mainstem position resulting in increased inspiratory pressure and decreased exhaled tidal volume.



   III.   Physiologic alterations during laparoscopic and thoracoscopic surgery. The fundamental differences between children and adults with regard to metabolic, cardiovascular, and respiratory performance are outlined in Chapter 1. Both laparoscopic and thoracoscopic operations mandate the introduction of exogenous CO2 to the respective body cavity to create a pneumoperitoneum or pneumothorax. The use of muscle relaxants, general anesthetics and the loss of the glottic closure mechanism with endotracheal intubation combined with the supine or Trendelenburg position and the pneumoperitoneum or the lateral position and pneumohemothorax conspire to produce particular challenges for the pediatric anesthesiologist.


               A.   Mechanical effects of insufflation


                       1.   The effects of pneumoperitoneum have been extensively examined in adults (15).


                            a.   Increases of intra-abdominal pressure (IAP) up to 20 cm H2O are accompanied by increases of central venous pressure (CVP), intrathoracic pressure, and cardiac output.


                            b.   Greater increases of IAP to approximately 40 cm H2O are accompanied by falls in CVP and cardiac output, with parallel changes in mean arterial pressure and moderate tachycardia.


                            c.   Subcutaneous emphysema has been reported as a result of pneumoperitoneum during laparoscopy; pneumothorax and pneumomediastinum may occur through retroperitoneal entry of insufflating gas into the thorax via anatomic foramina or diaphragmatic defects.


                            d.   A precordial stethoscope may actually be more revealing than an esophageal stethoscope; bilateral stethoscopy should be considered in such cases.


                       2.   Peak airway and plateau airway pressures in adults increase by 50% and 81%, respectively, whereas the compliance of the respiratory system decreases by 47% during the period of increased IAP.


                            a.   Experimental studies suggest that the risk of cardiorespiratory consequences with the development potential fatal emboli is directly related to peak pneumoperitoneal pressures (16).


                       3.   Following release of the pneumoperitoneum, peak and plateau pressures remain elevated by 37% and 27%, respectively, and respiratory compliance is 86% of the preinsufflation value (17).


                       4.   It is somewhat surprising yet consistent that gastroesophageal reflux is rare to nonexistent as assessed by pH probe and direct laryngoscopy as well as clinical signs and symptoms of reflux or aspiration notwithstanding the abdominal insufflation and head-down position (18,19).


                       5.   Occasional case reports of catastrophic cardiovascular collapse occurring during laparoscopy have been attributed to reflex-mediated bradycardia, hypercapnia, anoxia, decreased venous return and cardiac output, gas embolism, and a profound vagal response to peritoneal distension.


                       6.   Pneumoperitoneum alone and together with head-down tilt may shift the endotracheal tube into a deeper position, thereby getting in contact with the carina resulting in airway irritation, possible coughing, or bronchospasm or the endotracheal tube may advance into a right mainstem position resulting in increased inspiratory pressure and decreased exhaled tidal volume (20).


               B.   Monitoring CO2 insufflation


                       1.   Monitoring of end-tidal carbon dioxide (ETCO2) is a sensitive method of assessing the combined effects of endogenous and exogenous CO2 burden during CO2 insufflation.


                            a.   Strategies that enhance the accuracy of capnography in children are now well recognized, including fast sampling rates and distal airway sampling.




CLINICAL PEARL CO2 is the most soluble of the agents employed (CO2, nitrous oxide, and air) to produce pneumoperitoneum. Fatal gas embolization may nevertheless occur with CO2, particularly with prolonged procedures and more extensive tissue trauma.



               C.   Effects of CO2 insufflation


                       1.   Significant amounts of the insufflated gas may be absorbed from the pneumoperitoneum into the blood.


                            a.   CO2 is the most soluble of the agents employed (CO2, nitrous oxide, and air) to produce pneumoperitoneum.


                            b.   CO2 has been well tolerated for angiocardiography in doses up to 7.5 mL per kg in adults, whereas the injection of air in doses of 0.25 mL per kg in cats has resulted in death from coronary artery obstruction.


                            c.   Nitrous oxide is 68% as soluble as CO2 in blood and, although not flammable, can potentially support combustion directly or make an indirect contribution through bowel perforation and the release of volatile bowel gas (methane, hydrogen) (6).


                       2.   Insufflated CO2 rapidly equilibrates with tissues; CO2 pressure in alveolar air as well as arterial blood has been noted to increase within 5 minutes and pulmonary CO2 elimination increase after 15 minutes (7).


                            a.   In children, after 10 minutes of insufflation, 10% to 20% of expired CO2 derives from the exogenous CO2.


                            b.   The percentage of expired CO2 absorbed rises to 7.7% after 30 minutes of pneumoperitoneum and decreases rapidly after desufflation (8).


                            c.   Hypercarbia may result in elevated endogenous catecholamines accompanied by vasoconstriction, increased CVP, and increased inotropic, chronotropic, and arrhythmogenic effects on the heart.


                            d.   In addition, hyperkalemia, an increase in cerebral blood flow, acidosis, and cardiopulmonary depression may occur.


                            e.   The norepinephrine response has been found to increase with laparoscopic cholecystectomy and this may have particular implications for infants because of the presence of brown fat and its activation by norepinephrine.




CLINICAL PEARL Clinically, intravascular and cardiac gas embolism is diagnosed by a mill-wheel precordial murmur (by auscultation or precordial Doppler flow probe), hypotension, and detection of altered levels of the end-tidal gas (nitrogen, nitrous oxide, or CO2) by respiratory gas analysis.

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Aug 24, 2016 | Posted by in ANESTHESIA | Comments Off on Minimally Invasive Surgery

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