Saline flush test for bedside detection of misplaced subclavian vein catheter into ipsilateral internal jugular vein.

BACKGROUND: The most common misplacement during subclavian vein (SCV) catheterization is into the ipsilateral internal jugular vein (IJV). Chest radiography is the gold standard for the confirmation of correct placement. However, it is time-consuming and has the disadvantage of radiation exposure. We assessed the sensitivity and specificity of our previously reported 'flush test' for confirming correct central line placement. METHODS: All neurosurgical patients who underwent successful SCV catheterization on the right side by an infraclavicular approach were enrolled in this study. The flush test was performed by injecting 10 ml of normal saline in the distal port of catheter, while anterior angle of ipsilateral neck was palpated by an independent observer. A thrill of fluid elicited on the palm of hand (positive test) was suggestive of misplaced catheter into ipsilateral IJV. This was confirmed with chest fluoroscopy. RESULTS: SCV catheterization was performed in 570 patients. The flush test was positive in 19 patients (3.3%) and negative in 551 patients (96.7%). There were 26 (4.6%) misplacements as detected by chest radiography; 19 entered the IJV (3.3%) and seven the contralateral SCV (1.2%). In all patients who had a misplaced catheter into the ipsilateral IJV, the flush test results were positive, whereas the results were negative in patients who had normally placed catheter or misplaced catheter elsewhere. It was found that the test had 100% sensitivity and specificity to detect misplacement of SCV catheter into the ipsilateral IJV. CONCLUSIONS: Saline flush test is a simple and sensitive bedside test that successfully detects misplaced SCV catheters into ipsilateral IJV.

An assessment of the predictors of difficult intubation in patients with acromegaly.

Various clinical signs have been used for assessing difficult intubation in patients with acromegaly. These signs include the modified Mallampati classification, measurement of thyromental distance and head and neck movements. Some authors have also tried to establish a relationship between growth hormone levels and difficult intubation. We hypothesized that duration of symptoms in patients with acromegaly may have an association with difficult airway and difficult laryngoscopy. In this prospective study we evaluated tests of airway assessment such as: (i) the Mallampati grade; (ii) the thyromental distance; and (iii) the laryngoscopic grade (Cormack-Lehane). The growth hormone levels and the duration of disease symptoms were also examined. Significant correlation was observed between the Cormack-Lehane and Mallampati gradings (p = 0.05; rho = 19.3%), and between the thyromental distance and the duration of the symptoms (p = 0.03; rho = 26.9%). The incidence of Mallampati III and IV grades was higher in patients with acromegaly. Increased thyromental distance was noted in patients with a long duration of disease. However, increased thyromental distance was not associated with difficult laryngoscopy.

Patients Who Benefit from Intracranial Pressure Monitoring without Cerebrospinal Fluid Drainage After Severe Traumatic Brain Injury.

BACKGROUND: India has a high traumatic brain injury (TBI) burden and intracranial pressure monitoring (ICP) remains controversial but some patients may benefit. OBJECTIVE: To examine the association between ICP monitor placement and outcomes, and identify Indian patients with severe TBI who benefit from ICP monitoring. METHODS: We conducted a secondary analysis of a prospective cohort study at a level 1 Indian trauma center. Patients over 18 yr with severe TBI (admission Glasgow coma scale score < 8) who received tracheal intubation for at-least 48 h were examined. Propensity-based analysis using inverse probability weighting approach was used to examine ICP monitor placement within 72 h of admission and outcomes. Outcomes were in-hospital mortality and Glasgow Outcome Scale (GOS) score at discharge, 3, 6, and 12 mo. Death, vegetative, or major impairment defined unfavorable outcome. RESULTS: The 200 patients averaged 36 [18 to 85] yr of age and average injury severity score of 31.4 [2 to 73]. ICP monitors were placed in 126 (63%) patients. Patients with ICP monitor placement experienced lower in-hospital mortality (adjusted relative risk [aRR]; 0.50 [0.29, 0.87]) than patients without ICP monitoring. However, there was no benefit at 3, 6, and 12 mo. With ICP monitor placement, absence of cerebral edema (aRR 0.54, 95% confidence interval 0.35-0.84), and absence of intraventricular hemorrhage (aRR 0.52, 95% confidence interval 0.33-0.82) were associated with reduced unfavorable outcomes. CONCLUSION: ICP monitor placement without cerebrospinal fluid drainage within 72 h of admission was associated with reduced in-patient mortality. Patients with severe TBI but without cerebral edema and without intraventricular hemorrhage may benefit from ICP monitoring.

Complications related to positioning in posterior fossa craniectomy.

To compare complications associated with surgical position, a retrospective study was conducted on 260 patients who underwent posterior fossa craniectomy. Data collected from the records included demographic profile, American Society of Anesthesiologists' physical status score, neurological status, cranial nerve involvement, associated medical illnesses, anaesthetic technique, patient position, haemodynamic changes, duration of surgery, venous air embolism (VAE), blood loss/transfusion, postoperative complications, duration of ICU stay, and postoperative neurological status. Statistical analysis was done using the Chi-square test and independent t-tests. The demographic profile and preoperative associated medical illnesses of patients were comparable between groups. The incidence of end-tidal carbon dioxide (EtCO2) detected VAE was more (p=0.00) in the sitting position than the horizontal positions (15.2% vs. 1.4%). Blood loss/transfusion and the duration of surgery were significantly higher in the horizontal position (p<0.05). Brainstem handling was the most common cause of prolonged postoperative mechanical ventilation and was seen more in the sitting position. Lower cranial nerve functions were preserved better in the sitting position (p<0.05). Most postoperative complications (surgical or otherwise) were comparable between the groups (p>0.05). Most patients in both groups developed mild-to-moderate disability with independent lifestyle at the seventh postoperative day. To conclude, both sitting and horizontal positions can be used safely in posterior fossa surgeries.

Dynamic intraoperative kinking of flexometallic tube.

A 22-year-old male patient had two episodes of oxygen desaturation with concomitant increase in end-tidal carbon dioxide and airway pressure while undergoing transoral odontoidectomy under fluoroscopy. Dynamic kinking of the flexometallic endotracheal tube from compression by a Dingman retractor was responsible. Fluoroscopic imaging was helpful in confirming the etiology of sudden alteration in the monitoring parameters.

Recurrent bradycardia and delayed recovery in a neonate following repair of nasofrontal encephalocoele with holoprosencephaly and single cerebral ventricle.

Holoprosencephaly and single cerebral ventricle are uncommon congenital anomalies that are associated with a high rate of perinatal mortality. We describe a neonate who developed recurrent bradycardia along with delayed recovery following frontal craniotomy for the repair of a nasofrontal encephalocoele associated with holoprosencephaly and a single cerebral ventricle. The neonate, however, recovered following elective ventilation. Etiopathogenesis and management of such complications are discussed.

Airway pressure monitoring as an aid in the diagnosis of air embolism.

We designed a prospective study to compare the validity of airway pressure (AWP) monitoring with that of end-tidal CO2 (ETCO2) monitoring for early detection of air embolism. Subjects included 76 patients of both sexes who underwent neurosurgery in the sitting position. Anesthesia was maintained with O2, N2O, narcotics, pancuronium, and intermittent positive pressure ventilation (IPPV). Continuous monitoring was done of HR, ECG, intraarterial pressure, AWP, and ETCO2. A sudden and sustained decrease in ETCO2 during anesthesia in a hemodynamically stable patient was considered as a sign of air embolism. Concomitant changes in AWP and cardiovascular parameters were also recorded simultaneously. Onset time, stage of surgery, and duration of disturbances were recorded. At the same time, the chest was auscultated for any murmur. Aspiration of air through the CVP catheter was attempted for diagnosis and management of air embolism. ETCO2 monitoring detected 24 episodes (31.5%) of air embolism in 16 patients. We observed 10 episodes (13.1%) of tachycardia in nine patients and nine episodes (11.8%) of hypotension in eight of the 16 patients. Murmur was noted in four patients and air aspiration in six patients. Only six patients of the 16 had an increase in AWP along with the decrease in ETCO2. We conclude that AWP monitoring is neither a sensitive nor reliable indicator of air embolism.

Effect of prophylactic ondansetron on postoperative nausea and vomiting after elective craniotomy.

This prospective, randomized, placebo-controlled, double-blind study was designed to evaluate the efficacy of ondansetron, a 5-HT3 antagonist, in preventing postoperative nausea and vomiting (PONV) after elective craniotomy in adult patients. The authors also tried to discover certain predictors for postcraniotomy nausea and vomiting. We studied 170 ASA physical status I and II patients, aged 15 to 70 years, undergoing elective craniotomy for resecting various intracranial tumors and vascular lesions. A standardized anesthesia technique and postoperative analgesia were used for all patients. Patients were divided into two groups and received either saline placebo (Group 1) or ondansetron 4 mg (Group 2) intravenously at the time of dural closure. Patients were extubated at the end of surgery and episodes of nausea and vomiting were noted for 24 hours postoperatively in the neurosurgical intensive care unit. Demographic data, duration of surgery, and anesthesia and analgesic requirements were comparable in both groups. Overall, a 24-hour incidence of postoperative emesis was significantly reduced in patients who received ondansetron compared with those who received a saline placebo (39% in Group 1 and 11% in Group 2, P = .001). There was a significant reduction in the frequency of emetic episodes and rescue antiemetic requirement in patients treated with ondansetron; however, ondansetron did not significantly reduce the incidence of nausea alone (14% in Group 2 vs 5% in Group 1, P = .065). Prophylactic ondansetron had a favorable influence on PONV outcome measures such as patient satisfaction and number needed to prevent emesis (3.5). Side effects were similar in both groups. We conclude that ondansetron 4 mg given at the time of dural closure is safe and effective in preventing emetic episodes after elective craniotomy in adult patients.

Comparative study on proper placement of central venous catheters with & without stillete.

Observing a standard protocol, central venous catheterization was performed, via the right basilic vein, in 100 patients. At random, 50 patients received a catheter with stillete and 50 without stillete. Catheter tip was localized on a chest radiograph; 78 per cent with stilletes and 80 per cent without stilletes were properly positioned (either in the right atrium or the superior vena cava). Most common aberrant placement was in the right ventricle (14% of each type of catheters), and this did not produce any ventricular arrhythmias. Eight per cent of catheters with stillete and 6 per cent without stilletes were malplaced into the ipsilateral internal jugular vein. The incidence of proper and improper placement was similar with the two types of catheters. Silent catheter migration into the right ventricle is very frequent than recognized when an estimated catheter length is inserted without radiologic control.

End tidal carbon dioxide monitoring for detection of venous air embolism.

With the aim of defecting the potential hazard of air embolism, end tidal carbon dioxide (ETCO2) was monitored in 238 patients undergoing neurosurgery (in the sitting position), for early detection of venous air embolism (VAE). Fifty six episodes (26.3%) of significant fall in ETCO2 were observed in 41 patients (17.2%). Haemodynamic disturbances occurred in only 26 patients (10.9%) and were always preceded by a fall in ETCO2. Thirteen patients had positive air aspiration and cardiac murmurs were heard in only six. One patient suffered severe hypoxaemia (PaO2 = 55 mm Hg) whereas two had severe haemodynamic disturbances, but could be promptly resuscitated.

Potassium homeostasis during & after cardiopulmonary bypass.

Potassium homeostasis was studied in 30 patients undergoing cardiac surgery by employing cardiopulmonary bypass (CPB) and moderate hypothermia, and using morphine, N2O, relaxant anaesthesia. There was a trend for hypokalemia, and for maintaining a K+ level of 4-4.5 mmol/l, K+ infusion was required during CPB (9.017 mmol/m2 BSA/h). K+ infusion required in the post-operative period was considerably less (1.532 mmol/m2 BSA/h). There was no significant difference in the K+ levels of patients receiving preoperative diuretic therapy, as compared to those not receiving such therapy. Potassium requirement was significantly higher in patients under-going CABG and valvular heart disease, as compared to congenital heart disease. The mean urinary loss of K+ during bypass was found to be 2.95 mmol/m2 BSA/h, which was only 32 per cent of that required to be infused (9.017 mmol/m2 BSA/h). The mean excretion of K+ in the post operative period was significantly higher (4.53 mmol/m2 BSA/h) than K+ required to be infused during this period (1.532 mmol/m2 BSA/h).

Effect of cerebrospinal fluid return on success rate of percutaneous retrogasserian glycerol rhizotomy.

BACKGROUND AND OBJECTIVE: Trigeminal neuralgia is a painful syndrome, which has been commonly treated with percutaneous retrogasserian glycerol rhizotomy (PRGR). This study was performed to evaluate the effect of cerebrospinal fluid (CSF) return on the success rate of PRGR. METHODS: In this retrospective, nonrandomized, observational case series, 100 cases underwent 140 PRGRs under fluoroscopic guidance and were followed up for 6 to 36 months. The results were compared in the presence or absence of CSF return before PRGR. RESULTS: The PRGR was successful in 115 procedures (82.1%). CSF return was present in 84 procedures (60%) and, among these, 76 PRGRs (90.5%) produced pain relief. More than 1 year of pain relief without medications was present in 60 of 84 procedures (71.4%). CSF return before PRGR was absent in 56 procedures (40%) and success resulted in 39 procedures (69.6%). Pain relief for more than 1 year without medications was present in 19 procedures (33.9%). The success rate and duration of pain relief was greater in the presence of CSF return compared with absence of CSF return (P < .005). The incidence of complications such as facial dysesthesia (40%), corneal anesthesia (2.8%), herpes simplex (3.5%), and nonbacterial meningitis (0.7%) was not significantly different in 2 groups ( P > .05). CONCLUSION: The presence of CSF is an important factor in determining the success rate and duration of pain relief of PRGR.

Airway management in critically ill neurological patients.

Respiratory complications play an important part in the morbidity and mortality of critically ill neurological patients. Assurance of airway patency is of primary concern in such patients. A plethora of airway maintenance techniques and devices have been recommended for securing and maintaining the airway. But, translaryngeal intubation through the oral route is the safest and most preferred technique. Proper assessment and adequate preparation of the patient before intubation helps to avert crises. In difficult intubation one may secure and maintain the airway by placing a laryngeal mask airway (LMA). The role of early tracheotomy in patients who require prolonged ventilatory support can not be overemphasized. However, the development of inert and softer endotracheal tubes with low pressure cuff has reduced the complications associated with endotracheal intubation. Finally and most importantly the best place to acquire competence in securing the airway is the operation theater not the intensive care unit.

Cardiovascular responses to scalp infiltration with reduced concentration of adrenaline.

A prospective randomized controlled study was carried out in 41 adult neurosurgical patients to find out the hemodynamic effects following scalp infiltration with 0.5% lignocaine with or without adrenaline. The patients were divided randomly into two groups. Group I patients (n=21) received 0.5% lignocaine with adrenaline (1:8,00,000) for scalp infiltration and group II patients (n=20) received 0.5% lignocaine without adrenaline. Continuous monitoring of ECG, heart rate and arterial blood pressure was carried out every minute for 20 minutes following scalp infiltration. Blood loss while raising the scalp flap was assessed by the neurosurgeon who was unaware of the study. No significant hemodynamic disturbances were observed in either group. However, Group I patients had significantly (p=0.001) less bleeding on incision. From this study, we conclude that 0.5% lignocaine with adrenaline (1:8,00,000) does not give rise to any cardiovascular disturbances during and following scalp infiltration. Rather, it minimises blood loss while raising the craniotomy flap.

Venous air embolism: does the site of embolism influence the hemodynamic changes?

Three hundred and ninety-seven patients undergoing posterior cranial fossa surgery in the sitting position were prospectively studied to evaluate the incidence of venous air embolism (VAE) and its effects on hemodynamics. End-tidal carbon dioxide (ETC02) tension was monitored to diagnose VAE. A sudden and sustained decrease in ETC02 of more than 5 mmHg, in the absence of sudden hypovolemia, was presumed to be the result of VAE. The site of probable air entrainment (whether muscle, bone or tumor) was noted. Hemodynamic consequences were managed symptomatically. ETC02 monitoring detected VAE in 22% of the patients. The highest incidence of embolism resulted from muscles and tumor (40% in each case). Forty-two per cent of patients developed hypotension during the embolic episode (systolic BP less than 100 mmHg). Ten per cent of patients developed ventricular arrhythmias during the embolic episode. Air aspiration was successful in 4.8%. There were no statistically significant differences in the frequency of VAE among the different groups (P>0.05). Also, the frequency of hypotension and ventricular arrhythmias were not significantly different, irrespective of the source of VAE (P>0.05). The general condition of the patients in the preoperative stage had no influence on the incidence of embolism, hypotension or ventricular arrhythmias.

Hemodynamic response to skull pins application in children: effect of lignocaine infiltration of scalp.

BACKGROUND: Skull pins application following local anesthetic infiltration of scalp obtunds hemodynamic changes in adults. No such study is available in children. METHODS: 30 children undergoing elective suboccipital craniectomy with skull pins fixation, were randomly allocated either to control group I, or lignocaine group II. Whereas in group I, pins were applied without any scalp infiltration. In group II, pins were applied 1 min. after scalp infiltration with 0.5% lignocaine (plain) at each pin site. RESULTS: Mean arterial pressure and heart rate were recorded during pinning (peak increase),1,4,7 and 10 min later, and were compared with the baseline (parameters recorded approximately 20 min. after intubation). Mean arterial pressure in group I peaked from 77.0 +/- 9.19 to 113.87 +/- 13.7mmHg (P<0.001) and remained significantly high throughout the study period. In Group II peak increase in mean arterial pressure was from 91.64 +/- 16.39 to 101.85 +/- 15.87 mmHg (P<0.01) and remained high till 1 min. only. Pins placement resulted in significant increase in heart rate only during pinning (peak increase) and up to 1 min. in both the groups (P<0.01). CONCLUSIONS: In children, skull pins placement 1 min. after scalp infiltration with 0.5% lignocaine plain fails to prevent the hemodynamic changes arising during pins placement (peak change) and up to 1 min. after pins placement. However, the technique successfully blocks these changes beyond 1 min. post skull pins fixation.

Epilepsy surgery in India: All India Institute of Medical Sciences experience.

OBJECTIVES: Surgical treatment of epilepsy should be considered an important alternative to medical therapy. The identification of a suitable candidate, pre-operative evaluation requires a multidisciplinary team. The specific diagnostic studies required depend on the operative strategy and objective of surgical treatment. METHODS: In twenty patients with medically intractable epilepsy, who had clinical evaluation, electroencephalography (EEG), video-EEG monitoring using scalp electrodes, high resolution magnetic resonance imaging (MRI), neuropsychology, single photon emission computed tomography (SPECT) was done to localise the seizure focus. If the investigations were concordant resective surgery was performed. In case of frequent falls, atonic and tonic seizures, with generalised/multifocal discharges on EEG, a callostomy was done. Surgical outcome was assessed using Engel's 4 point scale. RESULTS: In 18 patients the seizure focus was localised, 13 had temporal lobectomy, five extra-temporal resection, and two had callosotomy. Fifteen patients had a follow-up of more than eight months, mean 20.5 (range 8-35 months), 13 had outcome I (seizure free), two had outcome II (occasional seizures), one-outcome III. Three were lost to follow-up and one patient died. There were no major post-operative complications. CONCLUSIONS: Surgical treatment of epilepsy is a safe, effective mode of therapy. Suitable candidates should be identified early and referred to appropriate centres.