Pott's puffy tumor: An unusual complication of rhino-orbito-cerebral mucormycosis.

Objective: To describe clinicoradiological features and surgical outcomes in a series of nine patients with rhino-orbito-cerebral mucormycosis (ROCM) who presented with Pott's puffy tumor (ROCM-PPT). Methods: The records of nine patients with ROCM-PPT seen between March 2020 and December 2021 were analysed. Clinical features, radiology, histopathology, operative findings, management and outcome were noted. Frontal sinus pneumatisation and outflow tract configuration was compared between patients and controls with ROCM and no PPT. Results: ROCM-PPT was diagnosed in 9 of 284 (3.2 %) patients with ROCM seen during the study period. There were six (66.7 %) males and the median age was 54 (IQR 46-60) years. Eight (88.9 %) patients had diabetes mellitus and seven (77.8 %) had been COVID-19 positive. Radiological features of osteomyelitis, subperiosteal abscess formation and dural enhancement were seen in all patients. No significant differences in pneumatisation or frontal sinus outflow tract configuration were noted between patients and controls. All patients underwent a craniectomy with frontal bone debridement and frontal sinus exteriorisation. All patients were treated with anti-fungal agents for several months. All patients had symptomatic improvement at a median follow-up of 21 (IQR 18-23) months. Repeat CT/MRI scans showed disease regression/resolution in six out of eight (75 %) patients with follow-up imaging, and stable disease in two others. Conclusions: ROCM-PPT is a rare, delayed complication of mucormycosis that was seen in larger numbers during the recent COVID-19 pandemic. Aggressive debridement of osteomyelitic bone and antifungal therapy results in a good outcome.

Correlation between Monocyte Gene Expression and Inflammation on Brain Imaging in Patients with Solitary Cerebral Cysticercus Granuloma.

Prior work has shown that 14 monocyte genes are upregulated in patients with different forms of parenchymal neurocysticercosis, including solitary cysticercus granuloma (SCG). The aim of this study was to investigate whether changes in inflammation associated with SCG seen on follow-up brain imaging are also reflected in changes in expression of these 14 genes. Peripheral blood CD14+ monocytes were isolated from 20 patients with SCG at initial diagnosis and at clinical and imaging follow-up of 6 months or more. Expressions of 14 target monocyte genes were determined by quantitative polymerase chain reaction at each visit. At a median follow-up of 14 months, the SCG had resolved in 11 patients, was persistent in four patients, and had calcified in five patients. Edema seen in the initial imaging in 17 patients had resolved in 15 patients and was markedly reduced in two patients. The expression levels of the monocyte genes LRRFIP2, TAXIBP1, and MZB1 were significantly lower at follow-up, regardless of the status of SCG on follow-up imaging. Our findings show that expression levels of monocyte genes involved with inflammatory processes decrease in patients with SCG concomitant with follow-up imaging that reveals a reduction in inflammation as revealed by complete or near-complete resolution of edema, as well as resolution or reduction in the enhancement of the granuloma.

Correlation Between Post-Radiosurgery Perinidal Hyperintensity and AVM Obliteration Following LINAC-Based Stereotactic Radiosurgery.

OBJECTIVE: We studied the correlation between new-onset perinidal hyperintensity (PH) on T2-weighted magnetic resonance imaging and obliteration of intracranial arteriovenous malformation (AVM) after stereotactic radiosurgery (SRS). METHODS: A retrospective study of 148 patients with an intracranial AVM who underwent SRS between September 2005 and June 2018 and had ≥1 radiological follow-up (early magnetic resonance imaging) 12-18 months after SRS was performed to analyze the correlation between PH (graded from 0 to 2) and AVM obliteration. RESULTS: Of the 148 patients, 95 were male. The mean patient age was 27.7 ± 12.4 years. Of the 148 AVMs, 105 (70.9%) were obliterated at a median follow-up of 27 months (interquartile range, 14-48 months). The cumulative 3-, 5-, 10-year obliteration rate was 51.8%, 70.8%, and 91.8%, respectively. New-onset PH was observed in 58 AVMs (39.2%; 50 obliterated and 8 not obliterated). No association was found between the pretreatment variables or dose delivered and the development of PH. Grade 2 PH was associated with the risk of symptoms developing compared with grade 1 PH (37.5% vs. 4%; P = 0.002). Symptomatic PH was more likely to develop in patients with a larger AVM (P = 0.05). On multivariate analysis, the presence of a single draining vein (odds ratio [OR], 2.9; 95% confidence interval [CI], 1.3-6.8), a lower median AVM volume (OR, 0.97; 95% CI, 0.6-0.89), a mean marginal radiation dose (OR, 1.29; 95% CI, 1.02-1.64), and the presence of PH (OR, 3.16; 95% CI, 1.29-7.71) were independent predictors of AVM obliteration. CONCLUSIONS: The incidence of PH after SRS for AVM was 39.2%. PH was an independent predictor of AVM obliteration after SRS. Grade 2 PH and a larger AVM volume were associated with symptomatic PH.

Adding Ketamine to Epidural Morphine Does Not Prolong Postoperative Analgesia After Lumbar Laminectomy or Discectomy.

BACKGROUND: Epidural opioids provide effective postoperative analgesia after lumbar spine surgery. Ketamine has been shown to reduce opioid-induced central sensitization and hyperalgesia. We hypothesized that adding ketamine to epidural opioids would prolong the duration of analgesia and enhance analgesic efficacy after lumbar spine surgery. METHODS: American Society of Anesthesiologists physical status class I to II patients aged between 18 and 70 years with normal renal function undergoing lumbar laminectomy were recruited into this single-center randomized trial. Patients were randomized to receive either single-dose epidural morphine (group A) or epidural morphine and ketamine (group B) for postoperative analgesia. The primary objective was to compare the duration of analgesia as measured by time to the first postoperative analgesic request. Secondary objectives were the comparison of pain scores at rest and movement, systemic hemodynamics, and the incidence of side effects during the first 24 hours after surgery. RESULTS: Fifty patients were recruited (25 in each group), of which data from 48 were available for analysis. The mean±SD duration of analgesia was 20±6 and 23±3 hours in group A and group B, respectively (P=0.07). There were 12/24 (50%) patients in group A and 17/24 (71%) patients in group B who did not receive rescue analgesia during the first 24-hour postoperative period (P=0.07). Pain scores at rest and movement, systemic hemodynamics, and postoperative complications were comparable between the groups. CONCLUSIONS: The addition of ketamine to epidural morphine did not prolong the duration of analgesia after lumbar laminectomy.

Effect of administration of tranexamic acid on blood loss and transfusion requirements in children undergoing posterior fossa tumor excision: a retrospective cohort study.

BACKGROUND: Surgical resection of posterior fossa tumors (PFT) in the pediatric age group often results in significant intraoperative blood loss. The primary objective was to assess the effect of tranexamic acid (TXA) on blood loss and transfusion requirement in pediatric patients undergoing excision of PFT. METHODS: In this retrospective study, all pediatric patients ≤ 18 years, who underwent PFT resection over a period of 7 years, were included. The patient and surgical characteristics, estimated blood loss (EBL), the need for blood and blood product transfusion, use of crystalloids, vasopressors, and any adverse events like seizures and thromboembolic events were recorded and compared between Group A who received TXA and Group B who did not. RESULTS: The study included 50 patients, out of which 36 belonged to Group A and 14 to Group B. The median age was 8 years (IQR, 2-17) and the mean BMI was 16.46 ± 4.11 kg/m2. The mean EBL was 224.29 ± 110.36 ml in group A (n = 36) and 362 ± 180.11 ml in group B (n = 14) (p = 0.007). The intraoperative volume of crystalloid use was significantly higher in group B (p = 0.04). The requirement of blood and blood product transfusion was similar between the groups, but the volume of blood transfusion per kg body weight was higher in group B, 8.3 (IQR, 6.7-11.1) ml/kg in Group A versus 10.5 (IQR, 8.1-16.1) ml/kg in Group B (p-value 0.3). The rates of complications noted in the form of seizures and thromboembolic events were comparable. CONCLUSION: The use of TXA in the pediatric population undergoing PFT resection aids in reducing blood loss during the surgery without increasing complications.

Cerebrospinal Fluid Procalcitonin-A Potential Biomarker for Post-Craniotomy Bacterial Meningitis.

Background: The literature regarding the utility of cerebrospinal fluid (CSF) procalcitonin (PCT) in the diagnosis of post-craniotomy bacterial meningitis and differentiating it from aseptic meningitis is sparse. Materials and Methods: CSF total WBC count, sugar, protein, and PCT were measured in febrile patients with suspected post-craniotomy meningitis during the first 30 days following an intradural cranial procedure for non-trauma indications. Patients were diagnosed as postoperative bacterial meningitis if CSF culture was positive (PBM, n = 28) or postoperative aseptic meningitis if CSF culture was sterile and there was no evidence of systemic infection (PAM, n = 31). CSF cytochemical parameters and PCT values were compared between the groups. Normal values of CSF PCT were obtained from 14 patients with noninfectious indications with hydrocephalus. Results: There was no significant difference in CSF total WBC count, sugar, and protein levels between PAM and PBM groups. The median PCT level in CSF in the normal group was 0.03 ng/mL (interquartile range [IQR] 0.02-0.07 ng/mL). CSF PCT in the PBM group (median 0.37 ng/mL, IQR 0.2-1.4 ng/mL) was significantly higher than normal values as well as PAM group (median 0.12 ng/mL, IQR 0.07-0.26 ng/mL (P = 0.0004). The area under the receiver operating characteristic (ROC) curve for CSF PCT was 0.767. A cutoff value of 0.12 ng/mL yielded a sensitivity of 85.7% (95% CI: 67.3% to 96%), specificity of 51.6% (95% CI: 33% to 69.9%), positive predictive value of 61.5% (95% CI: 51.9% to 70.3%), and negative predictive value of 80% (95% CI: 60.3.8% to 91.3%). Conclusions: CSF PCT assay in patients who are febrile during the first 30 days post-non-trauma neurosurgical procedures has a role in the early diagnosis of bacterial meningitis.

Impact of Grade on Survival in Pleomorphic Xanthoastrocytoma and Low Prevalence of BRAF V600E Mutation.

BACKGROUND: The prevalence of BRAFV600E mutations in pleomorphic xanthoastrocytoma (PXA) World Health Organization (WHO) Grade 2 and PXA WHO Grade 3 reported varies from 60% to 80%, yet the prognostic implications remain unclear. METHODS: We reviewed the demographic and clinicoradiologic data of 20 PXAs WHO Grade 2 and 13 PXAs WHO Grade 3, operated between 2007 and 2020, to ascertain extent of excision, recurrence, progression-free survival (PFS), and overall survival (OS). PXAs WHO Grade 3 were defined by the presence of >5 mitoses/high-power field. PXAs WHO Grade 3 received adjuvant radiation therapy and chemotherapy whereas PXAs received radiation therapy if subtotally excised. All samples were analyzed for the presence of BRAFV600E mutation using DNA obtained from paraffin blocks using droplet-digital polymerase chain reaction. RESULTS: The median patient age at diagnosis was 22 years with a male preponderance. BRAFV600E mutations were noted in 30% of tumors; 8 PXAs WHO Grade 2 and 2 PXAs WHO Grade 3. Recurrence occurred in 6 of 13 PXA WHO Grade 3 (55%) and 1 of 20 PXAs WHO Grade 2 (5%). At median follow-up of 45 months, the OS was 54 months and 33 months in the PXA WHO Grade 2 and PXA WHO Grade 3 groups, respectively (P = 0.02). OS and PFS did not differ between BRAF-mutated and BRAF-negative tumors. CONCLUSIONS: BRAFV600E mutations are less frequent in our population than reported in the literature. The BRAF mutation does not significantly impact OS and PFS. PXAs WHO Grade 3 are a distinct clinical entity, associated with worse PFS and OS than PXAs WHO Grade 2.

Imaging correlates of serum enzyme-linked immunoelectrotransfer blot (EITB) positivity in patients with parenchymal neurocysticercosis: results from 521 patients.

BACKGROUND: The presence of perilesional edema among patients with parenchymal neurocysticercosis (pNCC) of various lesion subtypes has not been correlated with results of serum enzyme-linked immunotransfer blot (EITB) for cysticercal antibodies. METHODS: In total, 521 patients with pNCC were classified into solitary cysticercus granuloma (SCG), multiple lesions, at least one of which was an enhancing granuloma (GMNCC), solitary calcified cysticercal lesion (SCC) and multiple calcified cysticercal lesions (CMNCC). The proportion of EITB positivity among each lesion subtype and its association with perilesional edema were determined. RESULTS: There were significantly higher positive EITB results in patients with GMNCC (90/111, 81.1%) compared with other lesion types. Perilesional edema was associated with positive EITB in patients with CMNCC. On univariate analysis, perilesional edema and GMNCC were associated with EITB positivity. On multivariate analysis, only GMNCC (OR 7.5; 95% CI 3.5 to 16.2) was significantly associated with EITB positivity. CONCLUSIONS: In patients with pNCC, the presence of perilesional edema is associated with a higher probability of a positive EITB result in patients with CMNCC, suggesting a synchronicity in the mechanisms associated with formation of perilesional edema and the antibody response in this subtype. In patients with enhancing granulomas, edema is not an independent predictor of a positive EITB, suggesting that the enhancement itself is associated with a strong antibody response.

Changes in pattern of presentation of patients with unilateral vestibular schwannoma over two decades: Influence of cell phone use in early diagnosis.

We aimed to study whether the increased use of cell phone in south Asia over the past two decades has impacted presentation of patients with vestibular schwannoma (VS). In this observational cohort study, data on cell phone use and severity of hearing loss and tumor size was collected using a questionnaire through a patient interview (n = 62) in consecutive patients with VS managed between 2017 and 2020. Association between cell phone use and severity of hearing loss and tumor size were studied and compared with our data published earlier when telephone use was not widely prevalent. 71% of the 62 patients (aged between 15 and 81 years) had large or giant VS. Pure tone audiometry showed moderately severe or profound hearing loss in77.4%. Sixty (96.7%) patients used cell phones. 50% of patients complained of difficulty in using their cell phone because of hearing loss. Compared to the earlier era, a higher proportion consulted an ENT surgeon first for hearing loss (59.7% vs 26%; p = 0.0005) and had small or medium sized tumors (29% vs 8%; p = 0.008) with a smaller mean tumor size (3.3 vs 3.9 cm; p = 0.03). Increased cell phone use has led to earlier diagnosis of VS and smaller tumours in recent years when compared to an earlier era. However, the vast majority of patients continue to present with severe to profound hearing loss and large tumors.

Monocyte Gene Expression Distinguishes Enhancing Brain Parenchymal Cysticercal Granulomas From Tuberculomas.

BACKGROUND: In patients with enhancing brain parenchymal lesions, parenchymal neurocysticercosis (pNCC) is often difficult to distinguish from tuberculoma, necessitating biopsy or empirical therapy. METHODS: In a prospective study, peripheral blood monocytes were isolated from patients with definitive pNCC (n = 39) and brain tuberculomas (n = 20). Patients with tuberculomas were diagnosed by the presence of concurrent systemic tuberculosis (n = 7), pathological or bacteriological confirmation (n = 5), and resolution of typical brain lesions following a therapeutic trial of antituberculous therapy (n = 8). Expressions of 14 NCC-associated monocyte genes were determined by quantitative polymerase chain reaction and analyzed for diagnostic usefulness between the 2 groups. RESULTS: Expression of 7 genes (TAX1BP1, RAP1A, PLCG2, TOR3A, GBP1P1, LRRFIP2, and FEZ2) was significantly higher in pNCC patients than in tuberculoma patients, with TAX1BP1 and RAP1A expressions more than 22- and 5-fold higher in pNCC patients. TAX1BP1 had the highest sensitivity of 66.7% at a specificity of 100% in discriminating pNCC from tuberculoma. A combination of TAX1BP1 and RAP1A increased the sensitivity to 84.6%, and including GBP1P1 with TAX1BP1 and RAP1A further increased sensitivity to 87.2% while maintaining specificity of 100%. CONCLUSIONS: Expression of a panel of genes in blood monocytes distinguishes pNCC from brain tuberculomas in patients with enhancing brain lesions.

Utility of Serial Optic Nerve Sheath Diameter Measurements in Patients Undergoing Cerebral Spinal Fluid Diversion Procedures for Hydrocephalus.

BACKGROUND: Functional status of cerebrospinal fluid (CSF) diversion procedure for hydrocephalus is difficult to assess on several occasions. We report the use of serial ultrasonographic measurement of optic nerve sheath diameter (ONSD) to assess the functional status of CSF diversion procedures in patients with hydrocephalus. METHODS: In this prospective observational study, ultrasonographic ONSD measurement was performed preoperatively, on postoperative days 1, 3, and 7 (n = 51 at each time point) and at follow-up (n = 31) in patients undergoing ventriculoperitoneal shunt or endoscopic third ventriculostomy for hydrocephalus. Change in ONSD values during first week after CSF diversion procedure and at follow-up were correlated with ventriculoperitoneal shunt/ETV function. RESULTS: ONSD ≥5.5 mm strongly correlated with clinical and imaging features of raised ICP (P < 0.001). Mean ONSD progressively decreased in the postoperative period and was the lowest on postoperative day 7 (P < 0.001) with >95% of patients having ONSD <5.5 mm at that time point. At follow-up (median, 12 months; n = 31), ONSD had further reduced in 78.6% of patients. All 3 patients with shunt dysfunction had an increase in the ONSD value compared with that on postoperative day 7. CONCLUSIONS: ONSD measurement on postoperative day 7 after CSF diversion correlates well with early surgical outcome but decreases further in many patients at a follow-up of 12 months. Rise in postoperative day 7 ONSD at follow-up correlates with failure of the CSF diversion procedure.

Early- and long-term surgical outcomes in 109 children with lipomyelomeningocele.

AIM: To determine the functional outcomes and risk factors for outcomes following surgery for lipomyelomeningocele (LMMC). METHODS: Data from 109 children with LMMC who underwent surgery from January 2008 to December 2017 were retrospectively studied to evaluate functional outcomes and possible risk factors for early- (at discharge from hospital or within 1 month of surgery) and long-term outcomes after surgery. RESULTS: There were 53 boys and 56 girls with median age of 36 months (IQR 12-90 months; range, 4 months to 18 years) at surgery. At presentation, neurological function was normal (asymptomatic group) in 28 (25.7%) children while there was neurological dysfunction (symptomatic group) in 81 (74.3%). Near total or radical excision of lipoma was done in 71 (65.1%) children. Six (5.8%) children had deterioration of neurological function in the post-operative period with recovery of function in three of them. There were no statistically significant risk factors for early outcomes. At a mean follow-up of 62.5 months (IQR 35-82 months; range, 12-146 months), 21 (27.6%) of the 76 symptomatic group children (including 59.3% with incomplete bladder dysfunction) showed improvement, 52 (68.4%) remained the same, while 3 (4%) deteriorated. In 31 children (symptomatic group) who developed symptoms after 1 year of age, early surgery after development of symptoms was associated with better chances of recovery (p = 0.0008). In the asymptomatic group, 23 (88.5%) had normal neurological function at mean follow-up of 57.5 months (IQR 30-77 months; range, 12-141 months) and 3 (11.5%) had neurological deterioration. The mean time to late deterioration (re-tethering) from surgery was 51.3 months (IQR 24-75 months; range, 24-84 months). Presence of syrinx on initial MRI (p = 0.008) and partial resection of the lipoma (p = 0.02) were independent risk factors for delayed deterioration. CONCLUSION: Radical resection of LMMC probably helps in preserving neurological function in > 90% of children at long-term follow-up. Fifty-five percent of children > 2 years of age with incomplete bladder dysfunction regained normal function following surgery. In children who develop symptoms after birth, early surgical intervention can reverse the neurological deficits.

Post Traumatic Hydrocephalus: Incidence, Pathophysiology and Outcomes.

BACKGROUND: Post-traumatic hydrocephalus (PTH) is a sequel of traumatic brain injury (TBI) that is seen more often in patients undergoing decompressive craniectomy (DC). It is associated with prolonged hospital stay and unfavorable outcomes. OBJECTIVE: To study the incidence and risk factors for development of PTH in patients undergoing DC in our institution and to review the literature on PTH with respect to incidence, risk factors, pathophysiology, and outcomes of management. METHODS: Data from 95 patients (among 220 patients who underwent DC for TBI and fulfilled the inclusion criteria) over a 5-year period at Christian Medical College, Vellore were collected and analyzed to study the incidence and possible risk factors for development of PTH. A review of the literature on PTH was performed by searching PUBMED resources. RESULTS: Thirty (31.6%) out of 95 patients developed post-traumatic ventriculomegaly, of whom seven (7.3%) developed symptomatic PTH, necessitating placement of ventriculoperitoneal shunt (VPS). No risk factor for development of PTH could be identified. The reported incidence of PTH in the literature is from 0.07% to 29%, with patients undergoing DC having a higher incidence. Younger age, subarachnoid hemorrhage, severity of TBI, presence of subdural hygroma, and delayed cranioplasty after DC are the main risk factors reported in the literature. CONCLUSIONS: PTH occurs in a significant proportion of patients with TBI and can lead to unfavorable outcomes. PTH has to be distinguished from asymptomatic ventriculomegaly as early as possible so that a CSF diversion procedure can be planned early during development of PTH.

Treatment Outcomes and Follow-Up Compliance after Less than Total and Total Resection of Vestibular Schwannomas in 294 Patients.

BACKGROUND: To document the outcomes and quality of follow-up compliance after planned subtotal, near-total and gross-total resection (STR, NTR, and GTR) of vestibular schwannomas (VSs). METHODS: This is a retrospective study of 294 consecutive patients, who underwent excision of a previously untreated VS, between 2005 and 2015. Outcomes including long-term tumor control, facial nerve outcomes, and compliance with follow-up advice were studied. RESULTS: The mean diameter of the tumors was 4.2 cm (±0.8 cm; range: 2.2-7.5 cm). Less than total excision was performed in 55 cases (18.7%), of which NTR was performed in 65% of the cases (n = 36) and STR in the remaining 35%. In the GTR group, 29.3% of patients had a good facial outcome (House and Brackmann [HB] grades 1-3) whereas 81.8% of patients undergoing NTR/STR had a good facial outcome. Follow-up was available in 94.5% of patients undergoing NTR/STR whereas only 69.5% of patients undergoing GTR could be followed up. Only 61.8% of the patients who had NTR/STR were compliant with our follow-up advice and were on either regular radiological surveillance or underwent stereotactic radiosurgery (SRS) as advised. In this group of patients, those with larger tumors and those who underwent a more extensive resection of their tumor were less likely to be compliant with follow-up advice (P = 0.043 and 0.007, respectively). Among patients who had GTR, nine patients (3.7%) were detected to have tumor recurrence at a mean interval of 5.5 years after surgery. CONCLUSION: "Incomplete" microsurgical excision followed by SRS is an effective strategy that fulfills the twin objectives of preservation of function and long-term tumor control. Considering follow-up attrition due to various causes, upfront SRS at the first follow-up visit-even for a small residue-may be a prudent strategy in selected patients.

Impact of COVID-19 Pandemic on Neurosurgical Practice in India: A Survey on Personal Protective Equipment Usage, Testing, and Perceptions on Disease Transmission.

BACKGROUND: There is a significant knowledge gap and anxiety among health care workers (HCWs) including neurosurgeons regarding in-hospital disease transmission and use of personal protective equipment (PPE) during the ensuing COVID-19 pandemic. OBJECTIVE: To assess present practice and perceptions among Indian neurosurgeons with respect to type of surgeries performed, PPE usage and SARS-CoV-2 testing. MATERIALS AND METHODS: A 12-item questionnaire on surgeries performed in the 6 weeks prior to the survey date, PPE usage, and preoperative SARS-CoV-2 testing was circulated electronically to Indian neurosurgeons from May 12, 2020 to May 31, 2020 and their responses analyzed. RESULTS: Two hundred forty-four neurosurgeons (237 males) participated in the survey; of whom, 230 had performed surgeries during the pandemic period. In total, 84.3% of respondents were performing semiemergency or emergency procedures only. N95 masks were utilized by only 83% of the respondents (n = 230) while performing surgical procedures. Only 40.9% of the respondents were satisfied regarding adequacy of available PPE. Preoperative SARS-CoV2 testing as well as testing of all asymptomatic patients prior to admission into ward/intensive care unit was perceived to be beneficial in reducing transmission risk by more than 85% respondents. More than 90% respondents felt that HCWs including neurosurgeons were at risk of acquiring infection through an outpatient consultation from an asymptomatic individual. CONCLUSIONS: Access to and utilization of appropriate PPE was lacking among the one-fifth of neurosurgeons who participated in this survey. To gain the confidence of neurosurgeons, hospitals should address their concerns regarding PPE and testing of patients prior to surgery and admission to the hospital.

Measurement of non-invasive blood pressure in lateral decubitus position under general anaesthesia - Which arm gives more accurate BP in relation to invasive BP - dependent or non-dependent arm?

BACKGROUND AND AIMS: Non-invasive blood pressure (NiBP) varies with the arm and body position. In the lateral decubitus position (LDP), the non-dependent arm reads lower, and the dependent arm reads higher pressure. We aimed to study the correlation between the NiBP and invasive arterial blood pressure (ABP) as anaesthesia progressed and its correlation in different BP ranges. METHODS: American Society of Anesthesiologists (ASA I-III) patients, between 18-70 years undergoing neurosurgical procedures in the LDP were studied. All were anaesthetised using a standard protocol, positioned in the LDP. NiBP was measured every 15 min in both dependent and non-dependent arms and correlated with the ABP. RESULTS: Intra-class correlation (ICC) done between the dependent arm NiBP and ABP showed good correlation for mean and systolic BP and moderate correlation for diastolic BP. ICC was 0.800, 0.846 and 0.818 for mean and 0.771, 0.782, 0.792 for systolic BP at 15 min, 1 h, and 2 h, respectively. The ICC between the non-dependent arm NiBP and the invasive ABP showed poor correlation for all BP (systolic, diastolic and mean). As anaesthesia progressed, the mean difference between the NiBP and the ABP decreased in the dependent arm and increased in the non-dependent arm. The strength of agreement between the NiBP and the ABP in various BP ranges showed moderate correlation for the dependent arm NiBP (0.45-0.54) and poor correlation (0.21-0.38) for the non-dependent arm. CONCLUSION: The NiBP of the dependent arm correlated well with ABP in LDP under general anaesthesia (GA). It is better to defer measuring NiBP in the non-dependent arm as the correlation with ABP is poor.