Haemato-biochemical and blood gas changes in bovines under multimodal anaesthesia

The study was conducted in six crossbred female cattle aged nine months to five years and weighing between 82-375 kg, to evaluate haematobiochemical and blood gas changes in during multimodal general anaesthesia. The animals were premedicated by intravenous administration of butorphanol (0.05mg/kg body weight) immediately followed by xylazine (0.02 mg/kg body weight). On achieving sedation, the animals were controlled in left lateral recumbency and induction of anaesthesia was carried out by intravenous administration of ketamine and midazolam at the dose rate of 4.0 and 0.2 mg/kg body weight respectively. Endotracheal intubation was performed and maintenance of general anaesthesia was carried out using isoflurane in 100% oxygen. The variation in total erythrocyte count, total leukocyte count, volume of packed red cells, platelet count and haemoglobin were non-significant before and after anaesthesia. A non-significant lymphocytopaenia with neutrophilia and mild variations in aspartate aminotransferase and alanine aminotransferase enzyme levels were also noticed. Blood pH reduced significantly (p<0.05) after induction of anaesthesia and returned to baseline values after recovery whereas PvCO2 (p<0.05) and base excess (p<0.01) values increased significantly after induction of anaesthesia. The blood bicarbonate did not alter significantly following induction of anaesthesia.

Comparison of Efficacy of Preloading With 0.9% Normal Saline with Premptive Dose of Ephedrine for Attenuation of Hemodynamic Response during Propofol Induction

Two different regimes propofol-normal saline vs propofol -ephedrine in prevention of hypotension during induction of anaesthesia, significant decrease in Systolic blood pressure (P<0.001) in both groups (both fluid and non-fluid groups) after induction of anaesthesia with propofol was observed. The incidence of hypo-tension was significant in control and crystalloid group when compared with ephedrine group. Systolic blood pressure decreased in all three groups and decrease in Systolic blood pressure at 2min, 3min and 5min with P values. 0.010, 0.00, 0.000 respectively. Also decrease in Mean Arterial pressure in P group when compared with E-group at 1, 2, 3, 4, and 5min with P values 0.038, 0.02, 0.012 and 0.029 respectively.

A quantitative evaluation of aerosol generation from upper airway suctioning during tracheal intubation and extubation sequences.

Background: Open respiratory suctioning is considered to be an aerosol generating procedure (AGP) and laryngopharyngeal suction, used to clear secretions during anaesthesia, is widely managed as an AGP. It is uncertain whether such upper airway suctioning should be designated an aerosol generating procedure (AGP) because of a lack of both aerosol and epidemiological evidence of risk. Aim: To assess the relative risk of aerosol generation by upper airway suction during tracheal intubation and extubation in anaesthetised patients. Methods: Prospective environmental monitoring study in ultraclean operating theatres to assay aerosol concentration during intubation and extubation sequences including upper airway suctioning for patients undergoing surgery (n=19 patients). An Optical Particle Sizer (particle size 300nm-10μm) was used to sample aerosol 20cm above the mouth of the patient. Baseline recordings (background, tidal breathing and volitional coughs) were followed by intravenous induction of anaesthesia with neuromuscular blockade. Four periods of oropharyngeal suction were performed with a Yankauer sucker: pre-laryngoscopy, post-intubation and pre- and post-extubation. Findings: Aerosol from breathing was reliably detected (65[39-259] particles.L-1 (median[IQR])) above background (4.8[1-7] particles.L-1, p<0.0001 Friedman). The procedure of upper airway suction was associated with much lower average concentrations of aerosol than breathing (6.0[0-12] particles.L-1, P=0.0007) and was indistinguishable from background (P>0.99). The peak aerosol concentration recorded during suctioning (45[30-75] particles.L-1) was much lower than both volitional coughs (1520[600-4363] particles.L-1, p<0.0001, Friedman) and tidal breathing (540[300-1826] particles.L-1, p<0.0001, Friedman). Conclusion: The procedure of upper airway suction during airway management is associated with no higher concentration of aerosol than background and much lower than breathing and coughing. Upper airway suction should not be designated as a high risk AGP.

Hyperspectral imaging for perioperative monitoring of microcirculatory tissue oxygenation and tissue water content in pancreatic surgery — an observational clinical pilot study

Background Hyperspectral imaging (HSI) could provide extended haemodynamic monitoring of perioperative tissue oxygenation and tissue water content to visualize effects of haemodynamic therapy and surgical trauma. The objective of this study was to assess the capacity of HSI to monitor skin microcirculation and possible relations to perioperative organ dysfunction in patients undergoing pancreatic surgery. Methods The hyperspectral imaging TIVITA® Tissue System was used to evaluate superficial tissue oxygenation (StO2), deeper layer tissue oxygenation (near-infrared perfusion index (NPI)), haemoglobin distribution (tissue haemoglobin index (THI)) and tissue water content (tissue water index (TWI)) in 25 patients undergoing pancreatic surgery. HSI parameters were measured before induction of anaesthesia (t1), after induction of anaesthesia (t2), postoperatively before anaesthesia emergence (t3), 6 h after emergence of anaesthesia (t4) and three times daily (08:00, 14:00, 20:00 ± 1 h) at the palm and the fingertips until the second postoperative day (t5–t10). Primary outcome was the correlation of HSI with perioperative organ dysfunction assessed with the perioperative change of SOFA score. Results Two hundred and fifty HSI measurements were performed in 25 patients. Anaesthetic induction led to a significant increase of tissue oxygenation parameters StO2 and NPI (t1–t2). StO2 and NPI decreased significantly from t2 until the end of surgery (t3). THI of the palm showed a strong correlation with haemoglobin levels preoperatively (t2:r = 0.83, p < 0.001) and 6 h postoperatively (t4: r = 0.71, p = 0.001) but not before anaesthesia emergence (t3: r = 0.35, p = 0.10). TWI of the palm and the fingertip rose significantly between pre- and postoperative measurements (t2–t3). Higher blood loss, syndecan level and duration of surgery were associated with a higher increase of TWI. The perioperative change of HSI parameters (∆t1–t3) did not correlate with the perioperative change of the SOFA score. Conclusion This is the first study using HSI skin measurements to visualize tissue oxygenation and tissue water content in patients undergoing pancreatic surgery. HSI was able to measure short-term changes of tissue oxygenation during anaesthetic induction and pre- to postoperatively. TWI indicated a perioperative increase of tissue water content. Perioperative use of HSI could be a useful extension of haemodynamic monitoring to assess the microcirculatory response during haemodynamic therapy and major surgery. Trial registration German Clinical Trial Register, DRKS00017313 on 5 June 2019

Conduct of anaesthesia

This chapter describes the safe conduct of general anaesthesia. Topics covered include induction of anaesthesia; maintenance of anaesthesia; total intravenous anaesthesia; and volatile anaesthetic agents. The important methods of monitoring the patient are discussed in detail, including monitoring of neuromuscular blockade, depth of anaesthesia and cardiac output. The measurement and control of patient temperature is described. The common surgical positions are described, together with their safety concerns. The chapter finishes with a discussion of the prevention and treatment of postoperative nausea and vomiting.

ACROMIO-AXILLO-SUPRASTERNAL NOTCH INDEX [AASI] : A SCREENING METHOD TO PREDICT DIFFICULT LARYNGOSCOPY IN PATIENT UNDERGOING GENERAL ANAESTHESIA AND REQUIRING ENDOTRACHEAL INTUBATION

Introduction and Aims: Difficult laryngoscopy [poor visualisation of larynx] is a surrogate indicator of difficult intubation and inability to manage difficult visualisation of larynx (DVL) can be life threatening. This study is performed to assess the ability of new index –Acromio -Axillo-Suprasternal Notch Index to predict difficult laryngoscopy in patient undergoing general anaesthesia in addition to other common predictors. Material and Methods: 100 patients with ASA class I and II candidate for general anaesthesia with endotracheal intubation were enrolled to this study. The four usual tests Modified MallampatiTest[MMT], Ratio Of Height to Thyromental Distance[RHTMD], Neck Circumference/ Thyromental distance, Sternomental distance difference were assessed before induction of anaesthesia. The new test AASI is calculated as follow: 1) Using a ruler a line is drawn vertically from the top of the acromion process to the superior border of the axilla at the pectoralismajor muscle named as line A. 2) A second line is drawn perpendicular to line A from the suprasternal notch (line B) and 3)That portion of line A that lies above where line B bisects line A is line C. AASI is calculated from the length of line C divided by line A[AASI = C/A]. By a skilled anaesthesiologist with more than 5 years of experience & who was unaware of the study, A laryngoscopy was done and based on Cormack-Lehane classification, grading of laryngoscopy was recorded. Sensitivity, specificity, positive predictive value and negative predictive value with 95% Confidence Interval for each airway predictor in isolation was studied. Results: DVL observed in 12% patients. We observed that sensitivity,specificity,PPV,NPV,AUC of Roc[95% confidence interval] of AASI was 80%[44.4-97.5%], 95.56%[89-98.8%],66.67%[42.22-84.6%],97.7%[92.6-99.33%},0.985[0.898-0.988]respectively & these results are better than other conventional methods of difficult airway predictors. Conclusion: AASI more than or equal to 0.5 is a good predictor of difficult visualisation of larynx (DVL) at direct laryngoscopy.

Effectiveness of Huffing Manoeuvre on Fentanyl Induced Cough

Aim: To determine the effect of huffing manoeuvre to preventing cough caused by intravenous administration of fentanyl during induction of anaesthesia. Study Design: Cross-sectional study Place and duration of study: General Anaesthesia Department, SICU and Pain Management, Civil Hospital Karachi from 1st June 2019 to 30th November 2019. Methodology: One hundred and sixty four patients meeting were enrolled. Every patient was taught to perform huffing manoeuvre by primary investigator visiting patient in ward at night before surgery. The act of huffing manoeuvre was lasts within 5 seconds. Any episode of cough within 60 seconds of fentanyl administration was classified as fentanyl induced cough. All patients were received Propofol (2mg/kg) for induction of anaesthesia. Results: The mean age was 46.42±8.92 years. Incidence of fentanyl induced cough was observed in 4.3% cases and huffing manoeuvre was effective in 95.7% cases. Conclusion: Huffing manoeuvre is an effecting method of reducing fentanyl induced cough in patients undergoing surgery, especially the manoeuvre prevents developing of severe fentanyl induced cough. Keywords: Fentanyl, Cough, Huffing manoeuvre, Analgesic opioids