endoscopic techniques that allow visualization of the airways of patients with pulmonary maladies have become a mainstay of medical treatment . since the invention of the rigid bronchoscope in 1897 by gustav killian , along with its refinement by chevalier jackson in the early 20 century , and shigeto ikeda 's introduction of the flexible bronchoscope in 1967 ; these instruments have become important clinical assets in the armamentarium of surgeons , intensivists , and pulmonologists . bronchoscopy , both fiberoptic and rigid , encompasses a number of diagnostic and therapeutic techniques to visualize the luminal surface of the trachea and proximal airways . flexible or fiberoptic bronchoscopy , allows for excellent visualization of the airway lumen and luminal surface including segmental and subsegmental bronchi with a relatively less traumatic instrument ; rigid bronchoscopy enables more therapeutic options but is limited to the trachea and main bronchi unless combined with a fiberoptic bronchoscope . bronchoscopy has become an important tool not only for visualizing abnormalities , but also for biopsy / tissue sampling , removal of secretions , mucous plugs , clots , and foreign bodies . more recent advances include stent placement for relief of airway compression , laser applications ( tumor resection ) , curtailing hemorrhage ( using cryocoagulation / cryotherapy ) , assisting in the placement of percutaneous tracheostomies , and securing the airway through facilitation of endotracheal tube placement . traditionally , complications of bronchoscopy were labeled minor , major / severe , or fatal . we discuss complications of both flexible and rigid bronchoscopy , categorizing them as mechanical or systemic for improved clarity . since its introduction in the 1960s , published rates of complication from fiberoptic bronchoscopy have ranged from < 0.1 to 11% , with mortality generally reported between 0 and 0.1% . complications of fiberoptic bronchoscopy mechanical complications of fiberoptic bronchoscopy include oro- or nasopharyngeal , vocal cord , and airway trauma as well as bronchospasm , laryngospasm , pulmonary derecruitment / atelectasis , pneumothorax , airway hemorrhage , and introduction or exacerbation of infection . in general , the rates of mechanical complications have been , and continue to be , quite low . the most consistently reported mechanical complications are related to airway manipulation / trauma and bleeding . a number of questionnaire - based , cross - sectional studies in the 1970s examined the reported rates of complications . a survey sent to 1,041 physicians who performed bronchoscopy reported 12 deaths in 48,000 cases , none of which were related to direct mechanical airway trauma and only two of which were associated with pneumonia ( both cases of pneumonia preceded the bronchoscopy ) . other mechanical complications included four brushes breaking off in the bronchi , at least one of which required thoracotomy , and 52 episodes of life - threatening airway complications ( most commonly bronchospasm ) . lindholm et al . , examined airway pressures of patients undergoing fiberoptic bronchoscopy and found that while spontaneously breathing patients had little change in airway pressures ( average of  5.2 cm h2o during inhalation and + 3.5 cm h2o during exhalation ) , intubated patients had a much wider range ( as low as  35 cm h2o during inhalation and higher than + 35 cm h2o during exhalation ) . this is most likely a combination of the small cross - sectional area remaining in the endotracheal tube , while a fiberoptic bronchoscope is in place , combined with dyssynchronous breathing from the patient . the pattern of these pressure changes leads to a decrease in vital capacity ( as tidal volume is restricted by high pressures and is lost via bronchoscopic suction ) , and a decrease in forced expiratory volume secondary to obstructed exhalation , which increases auto - positive end - expiratory pressure ( peep ) and functional residual capacity ( frc ) . this increase in auto - peep and frc may actually protect against hypoxemia , particularly if the patient is breathing 100% oxygen , although following removal of the bronchoscope the peep and frc will decrease , at this point atelectasis , bronchospasm , and laryngospasm may all lead to post - procedural hypoxemia unless treated promptly . prolonged suctioning during bronchoscopy can lead to further derecruitment and atelectasis , as well as worsening of post - procedural hypoxemia . despite these physiologic derangements , mechanical rates of pulmonary complications remain low with rates of pneumothorax from 0.07 to 0.16% , and respiratory failure from 0.2 to 0.31% in more recent studies . rates of more minor pulmonary mechanical complications including bronchospasm and laryngospasm range from 0.26 to 2% . , also called attention to the variability in cleaning practices of fiberoptic bronchoscopes ranging from water or saline only , to meat tenderizer , to alcohol , yet the rate of pneumonia ( as reported ) was remarkably low . this was confirmed by credle et al . , who reported only two instances of pneumonia in 24,521 procedures . kovaleva et al . , demonstrated that pseudomonas aeruginosa is the most commonly transmitted organism by an improperly cleaned bronchoscope , most likely secondary to its ability to form biofilm in the bronchoscope channels . infection can also be introduced from the oro- or nasopharynx into the lower respiratory tract ( as well as from an infected to a non - infected area of the lung ) . pharyngeal microbes are most common in this scenario : streptococcus , staphylococcus , moraxella , neisseria , and anaerobic bacteria . a prospective observational study of 13 hospitals confirmed a low reported rate of pneumonia as 0.6% ( five of 908 procedures ) in fiberoptic bronchoscopy . the expectation is that with modern , standard cleaning of bronchoscopes , and use of sterile technique where possible that these rates are even lower today . traditionally , bronchoscopic hemorrhage was thought to be frequently fatal and associated with large tumors . dedicated prospective data did not identify any cases of hemorrhage requiring transfusion , but did report bleeding in 0.7% ( six of 908 ) cases . those with preexisting bleeding disorders were not overrepresented among those patients with bleeding complications ; this suggests bleeding was likely mechanical and not coagulopathic . hemorrhagic complications were significantly higher in patients who had transbronchial biopsies , a trend that has persisted over decades . rates of bleeding were higher ( 2% ) in a prospective analysis of 205 cases in a teaching hospital , which could be attributed to the majority of operators being trainees , higher rates of interventional procedures ( biopsies ) , the specific patient population of the teaching hospital , or the use of more detailed outcome measurements ( i. e. , underreporting in prior studies ) . for example , hemorrhage was specifically quantified as > 40 ml within 15 min or > 200 ml within 24 h of the procedure . two decades later , a retrospective review demonstrated markedly lower rates of complications in a large academic medical center . hemorrhage ( > 50 ml ) occurred in only five ( 0.12% ) out of 4,273 cases of fiberoptic bronchoscopy , with only one requiring intubation , and an unrelated single case ( 0.02% ) of epistaxis . these results were confirmed in a greek study in 2008 that demonstrated a rate of 0.17% of pulmonary hemorrhage ( > 50 ml ) . systemic complications are primarily related to the procedure itself , medication administration , or patient comorbidities . systemic complications related to the procedure included vasovagal syncope , nausea / vomiting , aspiration , and hypoxemia . complications related to medications can be anesthetic or sedation - related , as well as procedural - medication related ( e. g. , local anesthetics , glycopyrrolate ) . finally , comorbidities including myocardial dysfunction , pulmonary insufficiency , or special cases such as increased icp can predispose to unique complications . initial rates of systemic complications varied widely based on reporting . in 1978 , pereira et al . , reported a 2.4% incidence of vasovasal reaction , and 0.2% nausea and vomiting . these rates were significantly decreased by 1995 where pue and pacht demonstrated a 0.05% incidence of vasovagal syncope and 0.1% incidence of vomiting . rates of aspiration are inconsistently reported across all studies likely reflecting the difficulty in making the diagnosis unless frank aspiration is observed . this class of complication is also likely intimately tied to the type and amount of sedation received by the patient . a cross - sectional study by simpson et al . , demonstrated wide variability in sedation practices at that time . as early as the 1970s , cases of death related to both sedation and local anesthetics were reported surrounding fiberoptic bronchoscopy . subsequently , no cases of sedation - related morbidity or local anesthetic toxicity were reported by pue and pacht in the 1995 study . they attributed their lower rate of complications to close monitoring ( including pulse oximetry ) and immediate availability of resuscitation equipment . it may be that standardization of sedation practices and the use of supplemental oxygenation also played a role in the decrease in sedation and anesthesia - related morbidity and mortality . during the initial decade of fiberoptic bronchoscopy myocardial infarction was associated with 33% of deaths , with another 17% related to preexisting pulmonary disease ( pneumonia and emphysema ) and another one of 12 patient deaths reported as being  in extremis  before the procedure . it has been reported that heart rate , blood pressure , and cardiac output all increase during fiberoptic bronchoscopy , and that increases in myocardial oxygen demand may induce arrhythmias or ischemia in at - risk patients . rates of st changes during fiberoptic bronchoscopy have been reported as high as 17% ( for patients over age 50 ) , but severe arrhythmias are cited less than 0.1% of the time . more difficult to quantify is the effect of bronchoscopy on patients with preexisting pulmonary disease ( often the indication for the procedure ) . pulmonary - related deaths from fiberoptic bronchoscopy are almost always related to the intersection of underlying disease ( large tumor and pneumonia ) and the stress of the procedure itself . increased airway pressures may be transmitted to the thoracic space and therefore raise intracranial pressure ( icp ) ( raising both systolic blood pressure and impairing venous return ) . however , the data on high extrinsic peep does not reliably show an increase in icp . a series of 26 fiberoptic bronchoscopies performed in patients with icp monitors demonstrated an increase in icp in 81% of cases , however the mean arterial pressure also increased leading to a normal cerebral perfusion pressure in all cases , and no cases had neurologic sequelae . it is therefore common practice not to withhold fiberoptic bronchoscopy in patients with elevated icp when the procedure is indicated , but to use sedation and paralysis if necessary to attempt to mitigate the increase in icp in unstable patients . complication rates from comorbid disease have fallen dramatically over time , which is likely attributable to improved monitoring and early intervention , as well as patient selection . furthermore , the incidence of complications is similar for patients in the bronchoscopy suite and the intensive care unit , indicating that fiberoptic bronchoscopy can be performed safely even in the sickest patients regardless of location . however , it is important to note that the rate of minor complications such as hypoxemia and nonmalignant arrhythmia is significantly higher in the icu population , so vigilance is paramount . nonetheless , flexible bronchoscopy has improved its capabilities by introducing enhancements that not only help in diagnosing malignancies , but also identifying areas of premalignancy [ figure 1 ] . these improvements include endobronchial ultrasound , electromagnetic navigation , autofluorescence bronchoscopy , narrow - band imaging , and confocal fluorescence microscopy . it is a support adjunct to help guide the site of tracheal puncture entry of the tracheostomy , and to avoid damage to the posterior wall of the trachea . however , this function of fiberoptic bronchoscopy is being challenged by the use of ultrasound . advances in equipment , monitoring techniques , and anesthetic medications continue to improve the margin of safety and make this procedure widely applicable . schematic diagram of flexible bronchoscope design demonstrating multiple changes that lend to its efficiency and value to the operator ( source : kovaleva et al . ) the technique of rigid bronchoscopy was pioneered by gustav killian in 1876 when he used an esophagoscope to remove a pork bone from a patient 's airway , thus preventing a tracheostomy . the rigid bronchoscope was improved upon by chevalier jackson in the early 20 century . though the invention of the flexible fiberoptic bronchoscope by ikeda in 1967 changed the field of bronchoscopy , the use of the rigid bronchoscope remains an important technique in the management of upper airway disease . in adults , the primary indications for using the rigid scope are central airway obstruction secondary to neoplastic and nonneoplastic pathologies , massive hemoptysis , mucus plugging , and blood clot removal , as well as foreign bodies . there has been an expanding interest in the management of central airway obstruction by pulmonologists and this has led to a renewed interest in rigid bronchoscopy . more than just treating cancer - related central airway obstruction mechanically , rigid bronchoscopy also makes possible a number of therapies such as laser / photoresection , endobronchial stents , balloon dilation , electrocautery , use of the argon beam , and cryotherapy . the wide channel of the rigid bronchoscope lends itself to easier removal of foreign bodies from the airway and debulking of masses , easier control of hemorrhage during therapeutic interventions in the trachea and mainstem bronchi , as well as easier dilation of proximal airways , and easier deployment of stents and other airway implantables , all while allowing for relative ease of ventilation . despite the multitude of indications and procedures : sex , age , and the aim of the procedure are not associated with complications . unlike fiberoptic bronchoscopy , rigid bronchoscopy is performed in the operating room under general anesthesia . performing rigid bronchoscopy under general anesthesia adds the potential complication of proceduralist and anesthesiologist sharing the airway but also adds a degree of safety by allowing the proceduralist to focus on airway intervention , while the anesthesiologist prevents and manages mechanical and systemic complications as they arise . here the anesthesiologists , with the bronchoscope operator , need to navigate the multiple approaches to airway management , such as apneic oxygenation , spontaneous ventilation ( assisted or otherwise ) , controlled mechanical ventilation , high frequency , and manual jet ventilation . relative contraindications to rigid bronchoscopy include uncontrolled coagulopathy , oxygenation , and ventilator demands that are at the clinical extremes , especially in the hands of an inexperienced operator . the type and rate of complications of rigid bronchoscopy are similar to those of flexible fiberoptic bronchoscopy and can likewise be divided into mechanical and systemic complications . complications of rigid bronchoscopy the most common mechanical complications of rigid bronchoscopy are trauma to the teeth , oropharynx , vocal cords or other glottic structures , laryngospasm , pneumothorax , and hemorrhage , and death . systemic complications include vasovagal syncope , hypoxemia , hypercarbia , medication effects of general anesthesia , arrhythmia , post - procedural respiratory failure , and death . it should be noted that there are relatively few prospective studies providing quantifiable complication rates during and after rigid bronchoscopy , so the true rate of complications resulting from the procedure is difficult to pinpoint and will vary by operator experience and institution . however , advances in equipment , monitoring , and anesthetic drugs have increased the overall margin of safety for rigid bronchoscopy . one retrospective study reviewed 775 cases of rigid bronchoscopy in a university hospital between 1992 and 1999 and found that 86.7% of cases occurred without any of the above listed complications . in this study 103/775 ( 13.3% ) of cases had complications , which included bleeding ( 6.6% ) , respiratory failure ( 5.3% ) , cough ( 0.6% ) , death ( 0.4% ) , and arrhythmia ( 0.3% ) . furthermore , rigid bronchoscopy seems to be safe to use in neurosurgery patients with space - occupying lesions . another notable retrospective study compared the complication rate of flexible fiberoptic bronchoscopy under topical anesthesia with the complication rate of rigid bronchoscopy under general anesthesia . lukomsky et al . , reviewed 3,449 rigid bronchoscopy procedures and complications associated with rigid bronchoscopy occurred in 173 of 3,449 cases ( 5% ) ; four rigid bronchoscope cases were complicated by pneumothorax [ figure 2 ] and six cases were complicated by death ( four due to hypoxia ) resulting in a fatality rate of 0.17% . post - bronchoscopy pneumothorax ( r ) ( source : author file ; tjp ) one underreported complication during rigid bronchoscopy with laser is airway fire [ figure 3 ] . with advances in technology , laser can now be used through flexible fiberoptic bronchoscopes , rigid bronchoscopes , during esophagoscopy , and during suspension microlaryngoscopy . due to this variety of applications , most reports of the incidence of airway fire are not specific to rigid bronchoscopy . in order to ensure the highest margin of safety in preventing airway fire , good communication must exist between the anesthesiologist and proceduralist , and the concentration of inhaled oxygen when the laser is in use should be < 40% . standard precautions should be adhered to during laser airway procedures , especially when flammable objects ( stents and endotracheal tubes ) are also present in the airway . sparking that may lead to airway fire ( source : google images ) as dutau et al . , have summarized ; ( i ) rigid bronchoscopy is preferred clinical tool for the majority of therapeutic pulmonary interventions , ( ii ) this tool has a dual use in that it can be used for visualization of pathology / tumors and for interventions , ( iii ) extensive training is need before it can be deployed by a practitioner , ( iv ) it is mandatory for use in stenting of the airway and with the use of silicone stents ( being reasonably minimally invasive ) , ( v )  can occasionally represent a bridge to definitive surgical management  , and ( vi ) when surgery is not possible due to a patient 's condition , rigid bronchoscopy can be used for palliative interventions . the rigid bronchoscope has had several new innovations that enhance patient safety and better facilitate its use for the practitioner . for example , the bryan - dumon ii rigid bronchoscope has an operator head with a universal instrumentation barrel . the operator head can be used on any dumon series color - coded tracheal and bronchial scope ( on the proximal end of the scope ) . the texas rigid integrated ( by wolff ) bronchoscope enables the operator to access a larger working area without visual interruption with the availability of separate channels for instruments and optics . while oxygen saturation is fairly easy to maintain with larger bronchoscopes , monitoring fio2 , minute ventilation , and airway pressures remain difficult to monitor , which can lead to hyperinflation and pneumothorax . the herner bronchoscope ( by wolff ) has a sampling / measuring port that allows monitoring of carbon dioxide , oxygen , and airway pressures . the expectation exists that technologic innovation will continue to improve the safety and efficacy of the rigid bronchoscope . the skilled and mature operator has fewer complications than novices , nonetheless , it is very safe even in the hands of trainees . however , the operator needs to be cognizant of methods to attenuate any bleeding complications . at the time of hemorrhage the nonbleeding lung must be protected . whether the patient is intubated or not , the patient should be positioned with the bleeding lung in the decubitus , dependent position ( if hemodynamics permit ) , and if necessary , a double lumen tube will have to be placed in the nonbleeding lung ( this will require special skills ) . other methods of bleeding control include the instillation of cooled saline into the bronchus and then clamping the bronchus with the fiberoptic scope tip . if this does not work then 5 ml of thrombin may be instilled ( 5,000 u dissolve in saline ) , or , alternately , 2 ml of 1:1,000 epinephrine mixed with normal saline in a 1:10 mixture in order to produce vasoconstriction , thereby reducing bleeding ( no more than three 2-ml aliquots are recommended ) . there has also been use of tranexamic acid with significant airway bleeding , and even activated factor vii has been instilled into the lungs with successful resolution of bleeding ( author tjp , case to be published ) . sometimes there are large thrombi that can block the airways once the bleeding stops , and these may need to be removed with cryotherapy , which has been in use for over 30 years [ figure 5 ] . it is also important during an episode of bleeding to have good visualization of the airways and the source of bleeding . usually the scope 's removal for manual cleaning to visualize the field is rarely needed , and only is necessary in the face of massive hemorrhage . in less than dire circumstances , the scope tip can be cleaned by gently rubbing it vertically against the mucosa of the cartilaginous part of the tracheal wall . if this maneuver does not clear the operator 's vision , then place the scope as described above against the tracheal wall and flush the operating port vigorously . bleeding airway after biopsy ( source : google images ) clot in bronchus that has been subjected to cryotherapy and removed ( source : author file ; tjp ) since its introduction in the 1960s , published rates of complication from fiberoptic bronchoscopy have ranged from < 0.1 to 11% , with mortality generally reported between 0 and 0.1% . complications of fiberoptic bronchoscopy mechanical complications of fiberoptic bronchoscopy include oro- or nasopharyngeal , vocal cord , and airway trauma as well as bronchospasm , laryngospasm , pulmonary derecruitment / atelectasis , pneumothorax , airway hemorrhage , and introduction or exacerbation of infection . in general , the rates of mechanical complications have been , and continue to be , quite low . the most consistently reported mechanical complications are related to airway manipulation / trauma and bleeding . a number of questionnaire - based , cross - sectional studies in the 1970s examined the reported rates of complications . a survey sent to 1,041 physicians who performed bronchoscopy reported 12 deaths in 48,000 cases , none of which were related to direct mechanical airway trauma and only two of which were associated with pneumonia ( both cases of pneumonia preceded the bronchoscopy ) . other mechanical complications included four brushes breaking off in the bronchi , at least one of which required thoracotomy , and 52 episodes of life - threatening airway complications ( most commonly bronchospasm ) . lindholm et al . , examined airway pressures of patients undergoing fiberoptic bronchoscopy and found that while spontaneously breathing patients had little change in airway pressures ( average of  5.2 cm h2o during inhalation and + 3.5 cm h2o during exhalation ) , intubated patients had a much wider range ( as low as  35 cm h2o during inhalation and higher than + 35 cm h2o during exhalation ) . this is most likely a combination of the small cross - sectional area remaining in the endotracheal tube , while a fiberoptic bronchoscope is in place , combined with dyssynchronous breathing from the patient . the pattern of these pressure changes leads to a decrease in vital capacity ( as tidal volume is restricted by high pressures and is lost via bronchoscopic suction ) , and a decrease in forced expiratory volume secondary to obstructed exhalation , which increases auto - positive end - expiratory pressure ( peep ) and functional residual capacity ( frc ) . this increase in auto - peep and frc may actually protect against hypoxemia , particularly if the patient is breathing 100% oxygen , although following removal of the bronchoscope the peep and frc will decrease , at this point atelectasis , bronchospasm , and laryngospasm may all lead to post - procedural hypoxemia unless treated promptly . prolonged suctioning during bronchoscopy can lead to further derecruitment and atelectasis , as well as worsening of post - procedural hypoxemia . despite these physiologic derangements , mechanical rates of pulmonary complications remain low with rates of pneumothorax from 0.07 to 0.16% , and respiratory failure from 0.2 to 0.31% in more recent studies . rates of more minor pulmonary mechanical complications including bronchospasm and laryngospasm range from 0.26 to 2% . the cross - sectional study from suratt et al . , also called attention to the variability in cleaning practices of fiberoptic bronchoscopes ranging from water or saline only , to meat tenderizer , to alcohol , yet the rate of pneumonia ( as reported ) was remarkably low . this was confirmed by credle et al . , who reported only two instances of pneumonia in 24,521 procedures . kovaleva et al . , demonstrated that pseudomonas aeruginosa is the most commonly transmitted organism by an improperly cleaned bronchoscope , most likely secondary to its ability to form biofilm in the bronchoscope channels . infection can also be introduced from the oro- or nasopharynx into the lower respiratory tract ( as well as from an infected to a non - infected area of the lung ) . pharyngeal microbes are most common in this scenario : streptococcus , staphylococcus , moraxella , neisseria , and anaerobic bacteria . a prospective observational study of 13 hospitals confirmed a low reported rate of pneumonia as 0.6% ( five of 908 procedures ) in fiberoptic bronchoscopy . the expectation is that with modern , standard cleaning of bronchoscopes , and use of sterile technique where possible that these rates are even lower today . traditionally , bronchoscopic hemorrhage was thought to be frequently fatal and associated with large tumors . dedicated prospective data did not identify any cases of hemorrhage requiring transfusion , but did report bleeding in 0.7% ( six of 908 ) cases . those with preexisting bleeding disorders were not overrepresented among those patients with bleeding complications hemorrhagic complications were significantly higher in patients who had transbronchial biopsies , a trend that has persisted over decades . rates of bleeding were higher ( 2% ) in a prospective analysis of 205 cases in a teaching hospital , which could be attributed to the majority of operators being trainees , higher rates of interventional procedures ( biopsies ) , the specific patient population of the teaching hospital , or the use of more detailed outcome measurements ( i. e. , underreporting in prior studies ) . for example , hemorrhage was specifically quantified as > 40 ml within 15 min or > 200 ml within 24 h of the procedure . two decades later , a retrospective review demonstrated markedly lower rates of complications in a large academic medical center . hemorrhage ( > 50 ml ) occurred in only five ( 0.12% ) out of 4,273 cases of fiberoptic bronchoscopy , with only one requiring intubation , and an unrelated single case ( 0.02% ) of epistaxis . these results were confirmed in a greek study in 2008 that demonstrated a rate of 0.17% of pulmonary hemorrhage ( > 50 ml ) . systemic complications are primarily related to the procedure itself , medication administration , or patient comorbidities . systemic complications related to the procedure included vasovagal syncope , nausea / vomiting , aspiration , and hypoxemia . complications related to medications can be anesthetic or sedation - related , as well as procedural - medication related ( e. g. , local anesthetics , glycopyrrolate ) . finally , comorbidities including myocardial dysfunction , pulmonary insufficiency , or special cases such as increased icp can predispose to unique complications . initial rates of systemic complications varied widely based on reporting . in 1978 , pereira et al . these rates were significantly decreased by 1995 where pue and pacht demonstrated a 0.05% incidence of vasovagal syncope and 0.1% incidence of vomiting . rates of aspiration are inconsistently reported across all studies likely reflecting the difficulty in making the diagnosis unless frank aspiration is observed . this class of complication is also likely intimately tied to the type and amount of sedation received by the patient . a cross - sectional study by simpson et al . , demonstrated wide variability in sedation practices at that time . as early as the 1970s , cases of death related to both sedation and local anesthetics were reported surrounding fiberoptic bronchoscopy . subsequently , no cases of sedation - related morbidity or local anesthetic toxicity were reported by pue and pacht in the 1995 study . they attributed their lower rate of complications to close monitoring ( including pulse oximetry ) and immediate availability of resuscitation equipment . it may be that standardization of sedation practices and the use of supplemental oxygenation also played a role in the decrease in sedation and anesthesia - related morbidity and mortality . during the initial decade of fiberoptic bronchoscopy myocardial infarction was associated with 33% of deaths , with another 17% related to preexisting pulmonary disease ( pneumonia and emphysema ) and another one of 12 patient deaths reported as being  in extremis  before the procedure . it has been reported that heart rate , blood pressure , and cardiac output all increase during fiberoptic bronchoscopy , and that increases in myocardial oxygen demand may induce arrhythmias or ischemia in at - risk patients . rates of st changes during fiberoptic bronchoscopy have been reported as high as 17% ( for patients over age 50 ) , but severe arrhythmias are cited less than 0.1% of the time . more difficult to quantify is the effect of bronchoscopy on patients with preexisting pulmonary disease ( often the indication for the procedure ) . pulmonary - related deaths from fiberoptic bronchoscopy are almost always related to the intersection of underlying disease ( large tumor and pneumonia ) and the stress of the procedure itself . . increased airway pressures may be transmitted to the thoracic space and therefore raise intracranial pressure ( icp ) ( raising both systolic blood pressure and impairing venous return ) . however , the data on high extrinsic peep does not reliably show an increase in icp . a series of 26 fiberoptic bronchoscopies performed in patients with icp monitors demonstrated an increase in icp in 81% of cases , however the mean arterial pressure also increased leading to a normal cerebral perfusion pressure in all cases , and no cases had neurologic sequelae . it is therefore common practice not to withhold fiberoptic bronchoscopy in patients with elevated icp when the procedure is indicated , but to use sedation and paralysis if necessary to attempt to mitigate the increase in icp in unstable patients . complication rates from comorbid disease have fallen dramatically over time , which is likely attributable to improved monitoring and early intervention , as well as patient selection . furthermore , the incidence of complications is similar for patients in the bronchoscopy suite and the intensive care unit , indicating that fiberoptic bronchoscopy can be performed safely even in the sickest patients regardless of location . however , it is important to note that the rate of minor complications such as hypoxemia and nonmalignant arrhythmia is significantly higher in the icu population , so vigilance is paramount . nonetheless , flexible bronchoscopy has improved its capabilities by introducing enhancements that not only help in diagnosing malignancies , but also identifying areas of premalignancy [ figure 1 ] . these improvements include endobronchial ultrasound , electromagnetic navigation , autofluorescence bronchoscopy , narrow - band imaging , and confocal fluorescence microscopy . it is a support adjunct to help guide the site of tracheal puncture entry of the tracheostomy , and to avoid damage to the posterior wall of the trachea . however , this function of fiberoptic bronchoscopy is being challenged by the use of ultrasound . advances in equipment , monitoring techniques , and anesthetic medications continue to improve the margin of safety and make this procedure widely applicable . schematic diagram of flexible bronchoscope design demonstrating multiple changes that lend to its efficiency and value to the operator ( source : kovaleva et al . ) the technique of rigid bronchoscopy was pioneered by gustav killian in 1876 when he used an esophagoscope to remove a pork bone from a patient 's airway , thus preventing a tracheostomy . the rigid bronchoscope was improved upon by chevalier jackson in the early 20 century . though the invention of the flexible fiberoptic bronchoscope by ikeda in 1967 changed the field of bronchoscopy , the use of the rigid bronchoscope remains an important technique in the management of upper airway disease . in adults , the primary indications for using the rigid scope are central airway obstruction secondary to neoplastic and nonneoplastic pathologies , massive hemoptysis , mucus plugging , and blood clot removal , as well as foreign bodies . there has been an expanding interest in the management of central airway obstruction by pulmonologists and this has led to a renewed interest in rigid bronchoscopy . more than just treating cancer - related central airway obstruction mechanically , rigid bronchoscopy also makes possible a number of therapies such as laser / photoresection , endobronchial stents , balloon dilation , electrocautery , use of the argon beam , and cryotherapy . the wide channel of the rigid bronchoscope lends itself to easier removal of foreign bodies from the airway and debulking of masses , easier control of hemorrhage during therapeutic interventions in the trachea and mainstem bronchi , as well as easier dilation of proximal airways , and easier deployment of stents and other airway implantables , all while allowing for relative ease of ventilation . despite the multitude of indications and procedures : sex , age , and the aim of the procedure are not associated with complications . unlike fiberoptic bronchoscopy , rigid bronchoscopy is performed in the operating room under general anesthesia . performing rigid bronchoscopy under general anesthesia adds the potential complication of proceduralist and anesthesiologist sharing the airway but also adds a degree of safety by allowing the proceduralist to focus on airway intervention , while the anesthesiologist prevents and manages mechanical and systemic complications as they arise . here the anesthesiologists , with the bronchoscope operator , need to navigate the multiple approaches to airway management , such as apneic oxygenation , spontaneous ventilation ( assisted or otherwise ) , controlled mechanical ventilation , high frequency , and manual jet ventilation . relative contraindications to rigid bronchoscopy include uncontrolled coagulopathy , oxygenation , and ventilator demands that are at the clinical extremes , especially in the hands of an inexperienced operator . the type and rate of complications of rigid bronchoscopy are similar to those of flexible fiberoptic bronchoscopy and can likewise be divided into mechanical and systemic complications . . complications of rigid bronchoscopy the most common mechanical complications of rigid bronchoscopy are trauma to the teeth , oropharynx , vocal cords or other glottic structures , laryngospasm , pneumothorax , and hemorrhage , and death . systemic complications include vasovagal syncope , hypoxemia , hypercarbia , medication effects of general anesthesia , arrhythmia , post - procedural respiratory failure , and death . it should be noted that there are relatively few prospective studies providing quantifiable complication rates during and after rigid bronchoscopy , so the true rate of complications resulting from the procedure is difficult to pinpoint and will vary by operator experience and institution . however , advances in equipment , monitoring , and anesthetic drugs have increased the overall margin of safety for rigid bronchoscopy . one retrospective study reviewed 775 cases of rigid bronchoscopy in a university hospital between 1992 and 1999 and found that 86.7% of cases occurred without any of the above listed complications . in this study 103/775 ( 13.3% ) of cases had complications , which included bleeding ( 6.6% ) , respiratory failure ( 5.3% ) , cough ( 0.6% ) , death ( 0.4% ) , and arrhythmia ( 0.3% ) . furthermore , rigid bronchoscopy seems to be safe to use in neurosurgery patients with space - occupying lesions . another notable retrospective study compared the complication rate of flexible fiberoptic bronchoscopy under topical anesthesia with the complication rate of rigid bronchoscopy under general anesthesia . lukomsky et al . , reviewed 3,449 rigid bronchoscopy procedures and complications associated with rigid bronchoscopy occurred in 173 of 3,449 cases ( 5% ) ; four rigid bronchoscope cases were complicated by pneumothorax [ figure 2 ] and six cases were complicated by death ( four due to hypoxia ) resulting in a fatality rate of 0.17% . one underreported complication during rigid bronchoscopy with laser is airway fire [ figure 3 ] . with advances in technology , laser can now be used through flexible fiberoptic bronchoscopes , rigid bronchoscopes , during esophagoscopy , and during suspension microlaryngoscopy . due to this variety of applications , most reports of the incidence of airway fire are not specific to rigid bronchoscopy . in order to ensure the highest margin of safety in preventing airway fire , good communication must exist between the anesthesiologist and proceduralist , and the concentration of inhaled oxygen when the laser is in use should be < 40% . standard precautions should be adhered to during laser airway procedures , especially when flammable objects ( stents and endotracheal tubes ) are also present in the airway . sparking that may lead to airway fire ( source : google images ) as dutau et al . , have summarized ; ( i ) rigid bronchoscopy is preferred clinical tool for the majority of therapeutic pulmonary interventions , ( ii ) this tool has a dual use in that it can be used for visualization of pathology / tumors and for interventions , ( iii ) extensive training is need before it can be deployed by a practitioner , ( iv ) it is mandatory for use in stenting of the airway and with the use of silicone stents ( being reasonably minimally invasive ) , ( v )  can occasionally represent a bridge to definitive surgical management  , and ( vi ) when surgery is not possible due to a patient 's condition , rigid bronchoscopy can be used for palliative interventions . the rigid bronchoscope has had several new innovations that enhance patient safety and better facilitate its use for the practitioner . for example , the bryan - dumon ii rigid bronchoscope has an operator head with a universal instrumentation barrel . the operator head can be used on any dumon series color - coded tracheal and bronchial scope ( on the proximal end of the scope ) . the texas rigid integrated ( by wolff ) bronchoscope enables the operator to access a larger working area without visual interruption with the availability of separate channels for instruments and optics . while oxygen saturation is fairly easy to maintain with larger bronchoscopes , monitoring fio2 , minute ventilation , and airway pressures remain difficult to monitor , which can lead to hyperinflation and pneumothorax . the herner bronchoscope ( by wolff ) has a sampling / measuring port that allows monitoring of carbon dioxide , oxygen , and airway pressures . the expectation exists that technologic innovation will continue to improve the safety and efficacy of the rigid bronchoscope . the skilled and mature operator has fewer complications than novices , nonetheless , it is very safe even in the hands of trainees . however , the operator needs to be cognizant of methods to attenuate any bleeding complications . at the time of hemorrhage the nonbleeding lung must be protected . whether the patient is intubated or not , the patient should be positioned with the bleeding lung in the decubitus , dependent position ( if hemodynamics permit ) , and if necessary , a double lumen tube will have to be placed in the nonbleeding lung ( this will require special skills ) . other methods of bleeding control include the instillation of cooled saline into the bronchus and then clamping the bronchus with the fiberoptic scope tip . if this does not work then 5 ml of thrombin may be instilled ( 5,000 u dissolve in saline ) , or , alternately , 2 ml of 1:1,000 epinephrine mixed with normal saline in a 1:10 mixture in order to produce vasoconstriction , thereby reducing bleeding ( no more than three 2-ml aliquots are recommended ) . there has also been use of tranexamic acid with significant airway bleeding , and even activated factor vii has been instilled into the lungs with successful resolution of bleeding ( author tjp , case to be published ) . sometimes there are large thrombi that can block the airways once the bleeding stops , and these may need to be removed with cryotherapy , which has been in use for over 30 years [ figure 5 ] . it is also important during an episode of bleeding to have good visualization of the airways and the source of bleeding . usually the scope 's removal for manual cleaning to visualize the field is rarely needed , and only is necessary in the face of massive hemorrhage . in less than dire circumstances , the scope tip can be cleaned by gently rubbing it vertically against the mucosa of the cartilaginous part of the tracheal wall . if this maneuver does not clear the operator 's vision , then place the scope as described above against the tracheal wall and flush the operating port vigorously . bleeding airway after biopsy ( source : google images ) clot in bronchus that has been subjected to cryotherapy and removed ( source : author file ; tjp ) the majority of complications , as expected , occur in patients with high levels of comorbid disease undergoing more extensive therapeutic interventions . bronchoscopy requires skilled operators and continues to evolve technologically to the advantage of both the physician and the patient . overall , both rigid and flexible bronchoscopy , are safe and effective procedures for diagnosis and treatment of airway and pulmonary pathology .
flexible and rigid bronchoscopes are used in diagnosis , therapeutics , and palliation . while their use is widespread , effective , and generally safe ; there are numerous potential complications that can occur . 
 mechanical complications of bronchoscopy are primarily related to airway manipulations or bleeding . 
 systemic complications arise from the procedure itself , medication administration ( primarily sedation ) , or patient comorbidities . 
 attributable mortality rates remain low at < 0.1% for fiberoptic and rigid bronchoscopy . here 
 we review the complications ( classified as mechanical or systemic ) of both rigid and flexible bronchoscopy in hope of making practitioners who are operators of these tools , and those who consult others for interventions , aware of potential problems , and pitfalls in order to enhance patient safety and comfort .