various causes of these complications are contrast agents , electrolyte disturbances , loss of airway reflexes , pulmonary aspiration , hydrocephalus , chest infection , and the need for prolonged intravenous fluids , diuretics , and ventilator support . associated systemic abnormalities and perioperative complications can have significant adverse effects on patient outcome . the scarcity of data about the systemic abnormalities in these patients prompted us to conduct a retrospective review to enumerate the perioperative problems in these patients and the factors associated with unfavorable neurological outcome . this is a retrospective review of the patients who underwent surgery for brainstem tumors at our institute between january 2002 and december 2009 . after approval of the ethics committee , data were collected by reviewing the patients ' medical records including ; anesthetic records and perioperative notes . following preoperative data were collected : age , sex , weight , american society of anesthesiologists physical status , associated systemic illness , cough and gag reflexes , type of tumor , and neurological deficits . the intraoperative data of blood transfusion and complications such as hemodynamic instability ( hypotension requiring vasopressor therapy ) , venous air embolism ( vae , sudden and sustained fall in etco2 by 5 mmhg or more ) , and hypothermia ( core temperature < 36c ) were recorded . postoperative data regarding mechanical ventilation , lower cranial nerve ( lcn ) function deterioration , glasgow coma scale ( gcs ) deterioration , occurrence of respiratory distress , residual tumor , reintubation , and tracheostomy , occurrence of various complications ( meningitis , electrolyte disturbances , chest infection , postoperative hydrocephalus , seizure , postoperative hematoma ) , duration of intensive care unit ( icu ) and hospital stay and glasgow outcome score ( gos ) at the time of hospital discharge were recorded . on the basis of gos at the time of hospital discharge , patients were divided into two groups as favorable gos group ( gos score : 4 or 5 ) and unfavorable gos group ( gos score : 1 - 3 ) . statistical analysis was performed using software stata 9.0 ( college station , texas , usa ) . t - test and fisher 's exact test were carried out for continuous and categorical variables respectively , to compare different variables between the two groups . statistical analysis was performed using software stata 9.0 ( college station , texas , usa ) . t - test and fisher 's exact test were carried out for continuous and categorical variables respectively , to compare different variables between the two groups . seven patients were excluded from the study because of incomplete data , and data analysis was done for 63 patients . twenty ( 31.7% ) patients presented with the involvement of lcns with impaired gag reflex . preoperative factors and outcome majority of patients were operated in prone ( 36 patients , 57% ) or sitting position ( 17 patients , 27% ) but , some patients were operated in supine position ( 8 patients , 13% ) and lateral position ( 2 patients , 3% ) as well . balanced anesthesia technique consisting of o2 : n2o , isoflurane , fentanyl , and vecuronium / rocuronium , was used in all cases . along with routine monitoring ( heart rate , electrocardiography , pulse oximetry , temperature and end - tidal co2 ) , monitoring of invasive blood pressure and central venous pressure was also carried out in all patients . seven ( 11.1% ) patients had vae during surgery and they were all operated in sitting position . fourteen patients were extubated immediately after surgery , and 49 were electively ventilated . of the 20 patients who presented with the involvement of lcns , 7 ( 35% ) patients had further deterioration in their lcns in the postoperative period , as shown by impaired cough reflex . all of these 7 patients had brainstem handling manifesting with hemodynamic disturbances during the intraoperative period . all the 13 ( 20.6% ) patients who developed chest infection in the postoperative period , had preexisting lcn palsies . ten ( 15.8% ) patients who were extubated after surgery required reintubation in the icu , 2 due to acute onset respiratory distress , 7 due to deterioration in the sensorium and 1 due to generalized seizures . in addition , another 3 patients required tracheostomy due to a superimposed chest infection , weaning failure , and prolonged ventilation . one underwent surgical evacuation whereas , the other was managed conservatively . in our study , meningitis occurred in 32 ( 50.8% ) patients and of them , 27 ( 84.4% ) had associated cerebrospinal fluid ( csf ) leak . four ( 6.3% ) patients had generalized seizure in the postoperative period , and in 3 of them hyponatremia ( na < 120 ) was the reason . postoperative complications and outcome mean duration of icu stay was 4.3 days ( range : 2 - 16 days ) and mean duration of hospital stay was 14.1 days ( range : 4 - 60 days ) . of 63 patients , 56 ( 88.9% ) patients had favorable outcome at hospital discharge whereas , 7 ( 11.1% ) patients had an unfavorable outcome . four ( 6.3% ) patients died in the postoperative period , 2 patients ( 3.2% ) remained severely disabled and 1 patient ( 1.5% ) was discharged in a vegetative state . factors which were found to be associated with unfavorable gos were deterioration of gcs , chest infection , need for reintubation and tracheostomy [ table 3 ] . in this study of patients with brainstem tumors , we examined the incidence of various perioperative factors and their influence on the neurological outcome at the time of hospital discharge . we observed a high incidence of preoperative hydrocephalus ( 43% ) and preexisting lcn palsies in ( 32% ) our study population . various intraoperative problems encountered in our patients were hemodynamic instability requiring vasopressor therapy , occurrence of vae , major blood loss requiring blood transfusion . we did not find any significant association between preoperative and intraoperative factors on neurological outcome . various postoperative factors found to be associated with unfavorable outcome were gcs deterioration , chest infection , and the need for reintubation and tracheostomy . infratentorial surgeries carries a higher rate of csf leak , which may contribute to a higher rate of postoperative meningitis . in our study , meningitis occurred in 32 ( 51% ) patients and 27 ( 84% ) of these patients had csf leak . several factors which can predispose to csf leak include tumor size , a dural invasion of the tumor , hydrocephalus , blood in csf , and brain edema . brainstem tumors patients are prone to develop a number of complications in the postoperative period leading to prolonged mechanical ventilation . factors responsible for increased risk of respiratory complications are damage to the respiratory center , lcn palsies , altered sensorium , pulmonary aspiration , need for reintubation and prolonged ventilation . chevron et al . , in a prospective case - control study , found that a low consciousness level correlated with the need for reintubation . the incidence of reintubation in neurosurgical patients , in general has been described as 0.56 - 8.2% and has been attributed to both anesthetic and surgical factors . however , none of these studies were conducted in patients of brainstem tumor . brainstem tumor patients may be more prone to reintubation because of the damage to the respiratory center , lcn palsies , and altered sensorium . this was the reason of high incidence of reintubation in our study ( 16% ) , as compared with the low incidence reported in general neurosurgical population . the impaired gag reflex is known to cause chest infection due to impaired swallowing , pooling of saliva in the oral cavity and silent aspiration . high incidence of postoperative elective ventilation , decreased sensorium , and reintubation are the other possible reasons for the postoperative chest infections . jallo et al . in a retrospective analysis of 41 children and adolescents with brainstem medullary tumors , reported loss of lcn in 46% of them , 11% of patients had pneumonia in the postoperative period and all of them required tracheostomy . reported that the predicting factors for postoperative pulmonary complications are prolonged mechanical ventilation ( 48 h ) , time spent in icu ( > 3 days ) , decreased in level of consciousness , duration of surgery ( 300 min ) , and preexisting chronic lung diseases . generalized seizures following neurosurgery may lead to deterioration of patient 's condition and the need for intubation and mechanical ventilation . ( for diverse types of pathologies ) in 511 patients reported 5.9% incidence of seizures . our incidence of 6% is in agreement with their observation . whereas , in their series , most common cause of seizures was tension pneumocephalus , it was hyponatremia in our series . the main reason for different etiology of seizures in their series versus ours could be the more frequent employment of sitting position in their study ( 48.9% vs. 27% ) . the retrospective nature of the study and the small sample size are the limitations of our study . a larger sample size with a multifactorial regression analysis would have shown independent predictors of the unfavorable neurological outcome . we found that the occurrence of gcs deterioration , chest infection , reintubation , and tracheostomy in the postoperative period is associated with unfavorable outcome . further , larger prospective studies are required for determination of independent predictors of unfavorable outcome .
background and aims : patients with brainstem tumors have many associated systemic abnormalities and are prone to develop perioperative complications . 
 we studied the problems associated with brainstem tumors and their influence on the postoperative neurological outcome.material and methods : retrospective review of records of patients who underwent surgery for brainstem tumors over a period of 8 years was done . 
 preoperative variables , perioperative complications and neurological outcome as assessed by glasgow outcome scale at the time of hospital discharge were noted . 
 association between perioperative factors and the unfavorable neurological outcome was evaluated.results:data of 70 patients were retrieved , 7 patients were excluded from the study because of incomplete data and data analysis was carried out for 63 patients . 
 we found that lower cranial nerve palsies ( 32% ) and hydrocephalus ( 43% ) were common preoperatively . 
 various intraoperative problems encountered were hemodynamic instability ( 56% ) , major blood loss requiring blood transfusion ( 40% ) and venous air embolism ( 11% ) , and postoperative problems were meningitis ( 51% ) , hypokalemia ( 38% ) , chest infection ( 21% ) , seizure ( 11% ) , deterioration of glasgow coma scale ( gcs , 11% ) , hyponatremia ( 8% ) , hydrocephalus ( 6% ) , respiratory distress ( 3% ) and operatives site hematoma ( 3% ) . 
 fifty - six ( 89% ) patients had favorable outcome at hospital discharge whereas , 7 ( 11% ) had an unfavorable outcome . 
 there was no association between pre- and intra - operative factors and the neurological outcome . 
 deterioration of gcs , chest infection , and the need for reintubation and tracheostomy were associated with unfavorable neurological outcome.conclusion:patients of brainstem tumors are at increased risk of perioperative complications . 
 some of the postoperative complications were associated with unfavorable neurological outcome .