Evaluation of Cerebral Perfusion Pressure, Cerebral Blood Flow, and Cerebral Oxygenation at Different Head of Bed Positions Using Transcranial Doppler and Near-Infrared Spectroscopy in Postoperative Neurosurgical Patients.

OBJECTIVES: Nursing postoperative neurosurgical patients with head of bed (HOB) elevation beyond 30° might be desired at times to prevent pulmonary complications. Due to the paucity of studies determining the effect of HOB beyond 30° on cerebral perfusion pressure (CPP), cerebral blood flow (CBF), and regional cerebral oxygenation (rSO2), this study was designed. METHODS: A total of 40 patients following elective neurosurgery for supratentorial tumors were studied in the neurosurgical intensive care unit three hours following admission. They were assessed for CBF velocities of middle cerebral arteries on either side using transcranial color Doppler (TCCD), rSO2 using near-infrared spectroscopy (NIRS), and mean arterial pressure measured at tragus level at various HOB positions. The estimated cerebral perfusion pressure (CPPe) was calculated from TCCD parameters, and the estimated intracranial pressure (ICPe) was then derived. Their variations at different HOB positions were noted. RESULTS: TCCD parameters such as peak systolic velocity (PSV) and mean flow velocity (MFV) did not significantly vary upon elevating HOB from 0° to 30° but reduced significantly when HOB was further elevated to 60° (p < 0.05). ICPe reduced significantly with a change of HOB positions from 0° to 60° (p < 0.001), and a significant reduction in CPPe was noticed when HOB was elevated to 60° (67.2 ± 10.1 mmHg vs. 74.7 ± 11.2 mmHg at 0°). However, none of these HOB positions affected rSO2 values. CONCLUSION: Postoperative nursing with positions up to 60° HOB can be tried in indicated patients following elective neurosurgery when complemented with CBF velocity and rSO2 monitoring and in whom CPP-guided therapy is not preferred.

Use of near infrared spectroscopy for the prediction of perioperative complications in patients undergoing elective microsurgical resection of cerebral arteriovenous malformations- a prospective observational trial (NIRSCAM trial).

PURPOSE: Cerebral arteriovenous malformations (AVM) represent focal abnormal areas of low resistance circulation which render the peri-nidal neuronal tissue susceptible to ischemia. The post-excision cerebral perfusion surge can result in hyperaemic complications.We hypothesised that Near Infrared Spectroscopy (NIRS)-guided perioperative management can aid in the prediction and prevention of perioperative complications in patients presenting for surgical excision of cerebral AVMs. We also intended to identify a threshold value of regional cerebral oxygen saturation (rScO2) to predict the incidence of perioperative complications. METHODS: This was a prospective observational study involving patients undergoing elective supratentorial AVM resection surgeries. Intraoperative rScO2 and hemodynamic monitoring were done and continued for postoperatively for 12 h. Any drift in rScO2 by > 12% from baseline was managed as per study protocol and perioperative adverse events were recorded and analyzed. Post surgery,for analytical purpose patients were categorized into two groups, Group A - patients without complications and Group B - patients who had complications postoperatively. RESULTS: Twenty-five patients presenting for surgical excision of cerebral AVM were recruited for this study of which 9 patients had postoperative adverse events and were allocated to group B. The ipsilateral mean rScO2 at the time of complication (Pc) was significantly lower in Group B than in group A [62.08 ± 9.33 vs.70.52 ± 7.17; p = 0.04]. The mean ipsilateral rScO2 drift from N2- N5 (i.e., post excision) was significantly higher in Group B than in Group A [12.01 ± 2.63% vs. 4.98 ± 5.7%;p = 0.02]. Mean ipsilateral rScO2 Drift ratio (N5 :N2) was significantly higher in group B as compared to group A [1.32 ± 0.01 vs. 1.01 ± 0.06;p < 0.001]. In the immediate post excision phase, the ipsilateral mean rScO2 was significantly higher in Group B at the post excision time point compared to Group A [ 83.03 ± 6.08 vs. 73.52 ± 7.07;p < 0.01)]. The mean ipsilateral rScO2 drift from N1-N6 (i.e., postoperatively) was significantly higher in Group B as compared to Group A [14.96 ± 0.080% vs. 6.88 ± 4.5% ; p < 0.01]. Similarly, the Mean Ipsilateral rScO2 Drift ratio (N6:N1) was significantly lower in group B as compared to group A [2.17 ± 0.02 vs. 1.05 ± 0.03 ;p < 0.0001]. CONCLUSIONS: In patients undergoing cerebral AVM resection, a post-resection ipsilateral rScO2 increase by > 12% with a drift ratio of > 1.3 could signify cerebral hyperemia. A postoperative ipsilateral rScO2 drift > 14.5% with a drift ratio of 2.1 from the baseline is associated with postoperative complications in our study. Further multi-centric randomized control trials are needed to support our research findings.

Electrocardiographic changes in patients with raised intracranial pressure from supratentorial brain tumors.

Objectives: A wide variety of electrocardiographic (ECG) changes has been described in the context of neurological catastrophe. There has been diverse and plentiful literature emphasizing the cardiac changes in acute cerebrovascular events and traumatic brain injury. In stark contrast, there is scarce literature on the incidence of cardiac dysfunction caused by raised intracranial pressure (ICP) resulting from brain tumors. The study aimed to observe the ECG changes concurrent with intracranial hypertension resulting from supratentorial brain tumors. Materials and Methods: This is a pre-specified subgroup analysis of a prospective and observational study on cardiac function in patients presenting for neurosurgery. Data of 100 consecutive patients of either sex between 18 and 60 years who presented with primary supratentorial brain tumors were analyzed. The patients were divided into two groups: Group 1 consisted of patients without clinical and radiological features of raised ICP and Group 2 consisted of patients with clinical and radiological features of raised ICP. A 12-lead ECG was obtained for every patient on the day before the neurosurgical procedure as part of the pre-anesthetic assessment. The cardiologist and the neuroanesthetist independently examined the ECG, and it was then classified and coded as per the standardized Minnesota code. Statistical analysis was performed with IBM SPSS (release 22.0; IBM Corp., Armonk, NY, USA). The normality of the distribution of continuous variables was tested using the Shapiro-Wilk test. Normally distributed variables were expressed as Mean ± SD. All nominal or categorical variables are described as frequencies and percentages. Categorical variables were compared using the Chi-square test or the Fisher's exact test. The normally distributed continuous variables were compared using Student's t-test. "P < 0.05" was considered statistically significant. Results: About 6% in Group 1 and 32% in Group 2 had abnormal ECG. This was significantly different in Group 2 compared to Group 1 (P < 0.05). No patients in Group 1 had sinus bradycardia, whereas it was observed in 12% of the patients in Group 2 (P = 0.02). ST-segment depression was found in 12% of patients in Group 2, whereas none had it in Group 1 (P = 0.02). ST-segment elevation was noticed in 16 % in Group 2 and 2% in Group 1 (P = 0.01). T-wave abnormalities were found in 16% compared to 4% in Group 1 (P = 0.03). Conclusion: In patients with supratentorial tumors, we observed that those with raised ICP had a higher incidence of ECG changes than those with normal ICP. In addition, repolarization abnormalities and arrhythmias were significantly higher in patients with raised ICP.

A prospective-randomized placebo-controlled trial comparing the effects of nebulized dexmedetomidine v/s dexmedetomidine-lignocaine mixture on intraoperative hemodynamics and surgical field quality in patients undergoing endoscopic transnasal transsphenoidal pituitary tumor surgery.

Background: During transnasal transsphenoidal pituitary surgery (TNTSS), the primary objective is to maintain stable hemodynamics while ensuring ideal surgical conditions. This study aimed to investigate the effect of nebulized dexmedetomidine on hemodynamic parameters and the quality of the surgical field during TNTSS. Methods: Seventy-five patients scheduled for TNTSS were randomized into three groups of 25 each and received preoperative nebulization with 5 mL of nebulizing fluid consisting of 1.5 µg/kg of dexmedetomidine with saline in dexmedetomidine (D) group; 1.5 µg/kg of dexmedetomidine with 2% lignocaine in dexmedetomidine-lignocaine (DL) group and normal saline in the control (S) group. Heart rate (HR), mean blood pressure, Formmers score, anesthetic requirement, and emergence were evaluated for each group. Results: Group S had significantly higher HR and mean arterial pressure than the other two groups across various time points during surgery (P < 0.01). The total requirements for fentanyl, propofol, sevoflurane, and labetalol and the incidence of delayed emergence were significantly higher in the S group compared to the other two groups (P < 0.01). The D and DL groups exhibited significantly better surgical field conditions than the S group. In all the parameters assessed, patients in the D group outperformed those in the DL group. Conclusion: The administration of nebulized dexmedetomidine, both alone and in combination with lignocaine, resulted in stable hemodynamics, favorable operative conditions, reduced anesthetic requirement, and facilitated prompt emergence during TNTSS. Nebulized dexmedetomidine proved superior to its combination with lignocaine across all evaluated parameters.

Evaluation of markers of cerebral oxygenation and metabolism in patients undergoing clipping of cerebral aneurysm under total intravenous anesthesia versus inhalational anesthesia: A prospective randomized trial (COM-IVIN trial).

INTRODUCTION: Anesthetic goals in patients undergoing clipping of cerebral aneurysm include maintenance of cerebral blood flow, oxygenation, and metabolism to avoid cerebral ischemia and maintenance of hemodynamic stability. We intend to study the influence of anesthetic agents on the outcome of aneurysmal subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: This is a prospective, randomized, parallel, single-center pilot trial approved by the Institutional Ethics Committee and is prospectively registered with the Clinical Trial Registry of India. Patients with aneurysmal SAH (aSAH) admitted to our institution for surgical clipping, fulfilling the trial inclusion criteria, will be randomized in a 1:1 allocation ratio utilizing a computerized random allocation sequence to receive either total intravenous anesthesia (n = 25) or inhalational anesthesia (n = 25). Our primary objective is to study the effects of these anesthetic techniques on cerebral oxygenation and metabolism in patients with aSAH. Our secondary objective is to evaluate the impact of these anesthetic techniques on the incidence of delayed cerebral ischemia and long-term patient outcomes in patients with aSAH. The Modified Rankin Score and Glasgow Outcome Scale (GOS) at discharge and 3 months following hospital discharge will be evaluated. An observer blinded to the study intervention will assess the outcome measures. DISCUSSION: This study will provide more insight as to which is the ideal anesthetic agent that offers a better neurophysiological profile regarding intraoperative cerebral oxygenation and metabolism, thereby contributing to better postoperative outcomes in aSAH patients.

A Comparative Study to Evaluate the Efficacy of Virtual Versus Direct Airway Assessment in the Preoperative Period in Patients Presenting for Neurosurgery: A Quest for Safer Preoperative Practice in Neuroanesthesia in the Backdrop of the COVID-19 Pandemic!

Objectives Neurosurgical patients with cervical spine pathologies, craniofacial and craniovertebral junction anomalies, recurrent cervical spine, and posterior fossa surgeries frequently present with an airway that is anticipated to be difficult. Although the routine physical evaluation is nonaerosol-generating, Mallampati scoring, mouth opening, and assessment of lower cranial nerve function could potentially generate aerosols, imposing a greater risk of acquiring severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) infection. Moreover, airway evaluation requires the patient to remove the mask, thereby posing a greater risk to the assessing anesthesiologist. Thus, we designed this study to evaluate the efficacy of virtual airway assessment (VAA) done via telemedicine in comparison to direct airway assessment (DAA), and assess the feasibility of VAA as a part of the preanesthetic evaluation (PAE) of patients presenting for neurosurgery in the backdrop of the COVID-19 pandemic. Materials and Methods A total of 55 patients presenting for elective neurosurgical procedures were recruited in this prospective, observational study. The preoperative assessment of the airway was first done by a remote anesthetist via an encrypted video call, using a smartphone which served the purpose of telemedicine equipment, followed by a direct assessment by the attending anesthetist. The following parameters were assessed: mouth opening (MO), presence of any anomalies of tongue and palate, Mallampati classification (MPC) grading, thyromental distance (TMD), upper lip bite test (ULBT), neck movements, and Look-Evaluate-Mallampati-Obstruction-Neck mobility (LEMON) scoring system. Statistical Analysis Demographic parameters were expressed as mean ± SD. Agreement between the values obtained by VAA and DAA parameters were analyzed with the Kappa test. Results We observed a "perfect agreement" between the DAA and VAA with regard to MO. Assessment of ULBT, neck movements, and the LEMON score had an overall "almost perfect agreement" between the DAA and VAA. We also observed a "substantial agreement" between VAA and DAA during the assessment of MPC grading and TMD. Conclusion Our study shows that PAE and VAA via telemedicine can reliably be used as an alternative to direct physical preanesthetic consultation in the COVID-19 scenario. This could reduce unnecessary exposure of anesthesiologists to potential asymptomatic COVID-positive patients, thereby protecting the available skilled workforce, without any significant compromise to patient care.

Anesthetic Management of Hashimoto's Encephalopathy Presenting for Spine Surgery.

Hashimoto's encephalopathy (HE) is a rare neuroendocrine disorder, and there are no reports regarding anesthetic implications in a patient diagnosed with HE. These patients can have a plethora of systemic manifestations involving cardiovascular, respiratory, renal, gastrointestinal, hematologic, and central nervous systems. Once diagnosed, meticulous preoperative assessment is essential to rule out systemic involvement and to reduce the perioperative morbidity. Perioperative steroid therapy, neuromonitoring in the perioperative period, opioid free analgesia, and avoidance of nephrotoxic drugs are of paramount importance in the management of such patients. Awareness of the clinical condition and extreme vigilance can detect relapses in the perioperative period. Thus, a meticulous preoperative assessment, balanced anesthesia, perioperative neuromonitoring, and steroid therapy are essential to reduce the perioperative morbidity.

Multimodal monitoring to aid detection and management of intraoperative seizures: a case report.

One of the primary goals in Neuroanesthesia is to preserve cerebral oxygenation and protect the brain from secondary injuries. Seizures have severe implications in the intraoperative period, as it can instigate an increase in cerebral metabolism and oxygen demand, thus causing cerebral hypoxia. Detection of intraoperative seizures is imperative in neurosurgical cases as the ramifications of intracranial hypertension and cerebral hypoxia caused by it can affect patient prognosis and perioperative outcomes. We report a case of detecting intraoperative seizures with the aid of patient state index and near infrared spectroscopy. Multi-modality monitoring aided in the management of a time-sensitive complication, which could otherwise have possibly led to secondary brain insult.

Finding the Calm in the Chaos: An Institutional Protocol for Anesthetic Management of a Patient for Neurosurgery during Coronavirus Disease 2019 Pandemic.

"Coronavirus disease 2019" (COVID-19) transmitted by a novel coronavirus via contact or droplet spread is a highly infectious disease, the containment of which requires vigilance and stringent infection control policies. In the backdrop of hospitals becoming hot zones and an increasing number of health care workers contracting the disease, it is crucial to formulate an approach while administering anesthesia during the testing times of COVID-19 pandemic. In this background, this comprehensive article deals with the perioperative management during this pandemic and includes risk stratification based on an innovative simple scoring system, rationale use of personal protective equipments, and infection prevention protocols. The document of updated literature, though not intended to replace any guidelines, is aimed at providing protocol to health care workers to protect themselves while providing the best care in this pandemic.

Effect of Low-Dose Dexmedetomidine on the Anesthetic and Recovery Profile of Sevoflurane-Based Anesthesia in Patients Presenting for Supratentorial Neurosurgeries: A Randomized Double-Blind Placebo-Controlled Trial.

Background Dexmedetomidine could be a suitable adjuvant in neuroanesthesia due to its analgesic and anesthetic-sparing properties with the added advantage of facilitating intraoperative neuromonitoring. However, its recovery profile is still debated upon, as in neuroanesthesia, a prompt recovery is essential for postoperative neurologic assessment. We designed this study to evaluate the effect of dexmedetomidine on the anesthetic and recovery profile of patients presenting for supratentorial neurosurgeries. Materials and Methods Forty adult patients undergoing supratentorial surgeries were recruited in this prospective, randomized, double-blinded study and were divided into two groups: group S and group SD. Both groups received sevoflurane and fentanyl for maintenance, whereas group SD alone received a low dose of dexmedetomidine infusion. Recovery parameters, opioid consumption, Richmond Agitation-Sedation Scale (RASS) and visual analogue scale (VAS) scores, incidence of nausea and vomiting, and intraoperative hemodynamics were analyzed. Results There were no statistically significant differences between the groups S and SD in case of recovery parameters-time taken (in minutes, presented as median with interquartile range [IQR]) for (1) eye-opening to command: 9.5 (8-18) versus 22.5 (5-47.5) ( p = 0.414); 2) following verbal command: 10.5 (8.25-29.5) versus 25 (10-28.75) ( p = 0.512); (3) extubation: 11 (9.25-22) versus 25 (10-30) ( p = 0.277); and (4) getting oriented to place, time, and date: 23 (20-52.75) versus 27.5 (25-36.5) ( p = 0.121). Fentanyl consumption was significantly less in group SD (451 ± 39.3) versus group S (524.3 ± 144.1) ( p = 0.034). The median RASS score with IQR and the median VAS scores with IQR were comparable between the groups at all time points. Of the 20 patients in group S, 5 had complaints of nausea and vomiting compared with none in the group SD, although it was not statistically significant. The hemodynamic parameters did not show a significant difference between the groups except for a surge in mean arterial pressure at 30 minutes in group S. Conclusion Low-dose dexmedetomidine as an adjuvant to sevoflurane- and fentanyl-based anesthesia could provide stable hemodynamics and lesser anesthetics and opioid consumption, without adversely affecting the recovery profile in patients undergoing supratentorial neurosurgical procedures.

A Rare Case of Rhinocerebral Mucormycosis Presenting as Garcin Syndrome and Acute Ischemic Stroke.

BACKGROUND: Mucormycosis is a rare fungal infection affecting immunocompromised patients, with the rhinocerebral variant as the most common presentation.1 Garcin syndrome is the progressive involvement of the cranial nerves resulting in total unilateral paralysis of cranial nerves, absence of sensory or motor deficits, and not associated with features of raised intracranial pressure.2 We report a case of invasive rhinocerebral mucormycosis presenting as Garcin syndrome and acute ischemic stroke. HOW TO CITE THIS ARTICLE: Nagendra V, Thakkar KD, Prasad Hrishi A, Prathapadas U. A Rare Case of Rhinocerebral Mucormycosis Presenting as Garcin Syndrome and Acute Ischemic Stroke. Indian J Crit Care Med 2020;24(11):1137-1138.

Effect of Pregabalin on Perioperative Headache in Patients with Aneurysmal Subarachnoid Hemorrhage: A Randomized Double-Blind, Placebo-Controlled Trial.

Background Patients with acute aneurysmal subarachnoid hemorrhage (aSAH) experience excruciating headache that is difficult to manage in resource-constrained settings. Pregabalin's (ß-isobutyl-GABA) analgesic, antiepileptic, and antiemetic properties make it an attractive adjuvant in pain management for these patients. Methods We conducted a double-blind, placebo-controlled, randomized clinical trial on 40 aSAH patients undergoing aneurysmal clipping to assess the effect of perioperative pregabalin in decreasing perioperative headache, anesthetic, and opioid requirement. Patients received either pregabalin (75 mg) or placebo twice daily soon after admission till 24-hour postoperative, in addition to paracetamol 650 mg thrice daily. Headache assessed using a visual analog scale (VAS) at five time points was compared using a mixed effects regression model. Results Pain assessed by VAS declined significantly more from the baseline in pregabalin recipients compared with placebo at preinduction (-3.6 vs.-1.8; p = 0.004), 12-hour (4.3 vs. 2.8; p = 0.014), and 24-hour postsurgery (4.7 vs. 2.9; p = 0.007), but not at the 6-hour postoperation (4.9 vs. 3.8; p = 0.065). Pregabalin recipients required a lower minimum alveolar concentration of sevoflurane to maintain a prespecified bispectral index of 40 and 60 (0.8 vs. 0.9; p = 0.014) and required fewer rescue analgesic doses in the 24  hours following surgery (1.8 vs. 3.3; p = 0.005). The intraoperative fentanyl requirement was not significantly different between the groups (10 µg/kg vs. 11.4 µg/kg; p = 0.065). There was no significant difference in the sedation scores. Conclusions Pregabalin 75 mg administered twice daily, during the perioperative period, was an effective adjunct in the management of the severe headache experienced by patients with aSAH and decreased the opioid and anesthetic requirement without significantly increasing sedation.

Head Rules Over the Heart: Cardiac Manifestations of Cerebral Disorders.

The Brain-Heart interaction is becoming increasingly important as the underlying pathophysiological mechanisms become better understood. "Neurocardiology" is a new field which explores the pathophysiological interplay of the brain and cardiovascular systems. Brain-heart cross-talk presents as a result of direct stimulation of some areas of the brain, leading to a sympathetic or parasympathetic response or it may present as a result of a neuroendocrine response attributing to a clinical picture of a sympathetic storm. It manifests as cardiac rhythm disturbances, hemodynamic perturbations and in the worst scenarios as cardiac failure and death. Brain-Heart interaction (BHI) is most commonly encountered in traumatic brain injury and subarachnoid hemorrhage presenting as dramatic electrocardiographic changes, neurogenic stunned myocardium or even as ventricular fibrillation. A well-known example of BHI is the panic disorders and emotional stress resulting in Tako-tsubo syndrome giving rise to supraventricular and ventricular tachycardias and transient left ventricular dysfunction. In this review article, we will discuss cardiovascular changes caused due to the disorders of specific brain regions such as the insular cortex, brainstem, prefrontal cortex, hippocampus and the hypothalamus; neuro-cardiac reflexes namely the Cushing's reflex, the Trigemino-cardiac reflex and the Vagal reflex; and other pathological states such as neurogenic stunned myocardium /Takotsubo cardiomyopathy. There is a growing interest among intensivists and anesthesiologists in brain heart interactions as there are an increasing number of cases being reported and there is a need to address unanswered questions, such as the incidence of these interactions, the multifactorial pathogenesis, individual susceptibility, the role of medications, and optimal management. KEY MESSAGES: BHI contribute in a significant way to the morbidity and mortality of neurological conditions such as traumatic brain injury, subarachnoid hemorrhage, cerebral infarction and status epilepticus. Constant vigilance and a high index of suspicion have to be exercised by clinicians to avoid misdiagnosis or delayed recognition. The entire clinical team involved in patient care should be aware of brain heart interaction to recognize these potentially life-threatening scenarios. HOW TO CITE THIS ARTICLE: Hrishi AP, Lionel KR, Prathapadas U. Head Rules Over the Heart: Cardiac Manifestations of Cerebral Disorders. Indian J Crit Care Med 2019;23(7):329-335.

A Study Comparing Propofol Auto-coinduction and Standard Propofol Induction in Patients Undergoing General Anesthesia Without Midazolam Pretreatment: A Prospective Randomized Control Trial.

BACKGROUND: Propofol has emerged as an induction agent of choice over the past two decades due to its quick, smooth induction and rapid recovery. The main concern for an anesthesiologist is the hemodynamic instability caused by the standard induction dose of propofol (2-3 mg/kg). AIM: We aim to study the efficacy of propofol auto-coinduction technique in comparison to the standard propofol induction technique in terms of the total induction dose requirement of propofol, the incidence of hemodynamic side effects and pain on injection, and the incidence of fentanyl-induced cough (FIC) in the absence of a synergistic agent like midazolam. MATERIALS AND METHODS: This was a prospective, observer-blinded, randomized controlled trial. The study was initiated after obtaining the institutional ethics committee approval and is registered in the Clinical Trials Registry India. Eighty American Society of Anesthesiology Physical Status I and II patients, of either sex, aged between 18 and 55 years, and scheduled for elective surgeries under general anesthesia were randomized into two equal groups. Patients allocated to Group I (auto-coinduction) received 20% of the calculated dose of injection propofol 2 mg/kg (i.e., 0.4 mg/kg) as the priming dose followed by injection fentanyl 1 µg/kg after 1 min and the remaining propofol was administered in titrated doses till loss of verbal response after 2 min. In Group II (control), patients received injection fentanyl 1 µg/kg followed by single bolus dose of injection propofol up to 2 mg/kg till loss of verbal response. Midazolam was not used for premedication or induction. Intubation was carried out only after ensuring achievement of optimum depth of anesthesia using bispectral index scale. The total dose of propofol administrated for induction, occurrence of pain on injection, severity of cough after fentanyl administration, hemodynamic parameters, and apneic episodes were recorded. STATISTICAL ANALYSIS: All data were expressed as mean ± 2 standard deviation. For statistical analysis, SPSS software version 16 (SPSS Inc., 2007, Chicago, IL, USA) was used. RESULTS: The mean dose of injection propofol required for induction was significantly lower in Group I (67.0 ± 17.9 mg) when compared with Group II (111.3 ± 17.6 mg) (P < 0.01). The mean heart rate was significantly higher (P < 0.01) and the mean blood pressure was significantly lower in Group II (P < 0.01) when compared to Group I at 1 min postinduction, immediately after intubation, and 5 min after induction. The incidence of complications such as hypotension, pain on injection, and FIC was higher in Group II (50%) as compared to Group I (18%). CONCLUSION: In our study, we found that the induction dose requirement of propofol was significantly lower in the auto-coinduction group when compared to the conventional induction group. The auto-coinduction technique offered a stable hemodynamic profile, reduced pain on injection, and less incidence of FIC as compared to the conventional propofol induction technique.

Magnetic resonance imaging (MRI) induced 'hypoxia artifacts' on pulse oximetry: how reliable are MRI compatible monitoring devices?

Distinguishing a monitoring artifact requires expertise and adeptness. This can be practically challenging during the course of an anesthetic. We report a case, wherein we experienced episodes of aberrant pulse-oximeter values suggestive of desaturation with normal waveforms, occurring during a particular sequence of magnetic resonance imaging (MRI) performed under general anesthesia, which in fact was an artifact induced by the 3 T MRI during the diffusion tensor imaging sequence.