Cardiac surgery-associated acute kidney injury

Cardiac surgery-associated acute kidney injury (AKI) is a major health problem that is extremely common and has a significant effect on cardiac surgical outcomes. AKI occurs in nearly 30 % of patients undergoing cardiac surgery, with about 1-2 % of these ultimately requiring dialysis. The development of AKI predicts a significant increase in morbidity and mortality independent of other risk factors. The pathogenetic mechanisms associated with cardiac surgery-associated AKI include several biochemical pathways, of which the most important are hemodynamic, inflammatory and nephrotoxic factors. Risk factors for AKI have been identified in several models, and these facilitate physicians to prognosticate and develop a strategy for tackling patients predisposed to developing renal dysfunction. Effective therapy of the condition is still suboptimal, and hence the accent has always been on risk factor modification. Thus, strategies for reducing preoperative anemia, perioperative blood transfusions and surgical re-explorations may be effective in attenuating the incidence and severity of this complication.

Urinary tract infections in the critical care unit: A brief review

The use of indwelling catheters in the Critical Care Units (CCUs) has a major role in determining the incidence and the morbidity as well as mortality from hospital-acquired urinary tract infections (UTIs). Instituting evidence-based protocols can significantly reduce both the prevalence of indwelling catheterization as well as the incidence of hospital-acquired UTIs. The prevalence of catheter-associated urinary tract infections (CAUTIs) in the CCUs is directly linked to the widespread use of indwelling catheters in these settings. CAUTIs result in significant cost escalation for individual hospitals as well as the healthcare system as a whole. A UTI is an inflammatory response to colonization of the urinary tract, most commonly by bacteria or fungi. A UTI should be differentiated from the mere detection of bacteria in the urinary tract. This condition, referred to as asymptomatic bacteriuria, is common and does not require treatment, especially in the patient with an indwelling urinary catheter. A CAUTI occurs when a patient with an indwelling urinary catheter develops 2 or more signs or symptoms of a UTI such as hematuria, fever, suprapubic or flank pain, change in urine character, and altered mental status. CAUTI is classified as a complicated UTI. The current review highlights the important management issues in critical care patients having CAUTI. We performed a MEDLINE search using combinations of keywords such as urinary tract infection, critical care unit and indwelling urinary catheter. We reviewed the relevant publications with regard to CAUTI in patients in CCU.

Attenuation of the haemodynamic responses to tracheal intubation with gabapentin, fentanyl and a combination of both: A randomised controlled trial

Background and Aims:

We conducted a prospective, randomised, double-blind, controlled clinical trial to examine (1) whether a single preoperative dose of 800 mg gabapentin would be as effective as 2 μg/kg of intravenous (IV) fentanyl in blunting the haemodynamic response to tracheal intubation and (2) whether a combination of both would be more effective in this regard.

Methods:

Seventy-five patients (American Society of Anaesthesiologists physical status I), aged 20–50 years were allocated into one of three groups: 2 μg/kg IV fentanyl, 800 mg oral gabapentin or a combination of both. Gabapentin was administered 2 h and fentanyl 5 min before induction of anaesthesia, which was achieved with 5 mg/kg thiopentone, and tracheal intubation facilitated with 0.1 mg/kg vecuronium. Laryngoscopy lasting a maximum of 30 s was attempted 3 min after administration of the induction agents. Serial values of mean arterial pressure (MAP) and heart rate (HR) were compared among the three groups and with the respective preinduction measurements.

Results:

Patients receiving gabapentin 800 mg alone showed remarkable increases in HR and MAP in response to tracheal intubation (P < 0.05). The increases were similar for the other two regimens. These haemodynamic changes were lesser in patients receiving fentanyl and the combination of gabapentin and fentanyl.

Conclusion:

Oral gabapentin does not produce significant reduction in laryngoscopy and tracheal intubation induced sympathetic responses as compared to IV fentanyl or the combination of gabapentin and fentanyl.

Comparison of cognitive, ambulatory, and psychomotor recovery profiles after day care anesthesia with propofol and sevoflurane

PURPOSE

We compared the recovery profile of propofol and sevoflurane when used for maintenance of anesthesia in elective day care operative procedures.

METHODS

One hundred ASA physical status I and II patients, aged between 18 and 50 years, were randomly assigned to receive either propofol-nitrous oxide or sevoflurane-nitrous oxide maintenance of anesthesia. Early and intermediate recovery in terms of cognitive and ambulatory functions was recorded. Psychomotor testing, in the form of Trieger dot test and digit symbol substitution test, were performed before surgery and in the post-anesthesia care unit at 15 min, 30 min, 1 h, 2 h, and 4 h following nitrous oxide switch-off to evaluate intermediate recovery.

RESULTS

There were no significant differences in recovery of early cognitive functions between the two groups, except that patients in the sevoflurane group were more responsive at around 10 min following nitrous oxide switch-off and "recalled address" earlier than patients in the propofol group. There was no significant difference in between the two groups with regard to "home-readiness."

CONCLUSIONS

Recovery from sevoflurane anesthesia, especially with regard to cognitive functions, may be slightly faster than from propofol, but the difference is not sufficiently significant to affect the time to "home-readiness" in patients undergoing day care surgery.

Doppler resistive index to reflect risk of acute kidney injury after major abdominal surgery: A prospective observational trial

Background and Aims

Doppler renal resistive index (RI) has been studied to find its association with postoperative acute kidney injury (AKI). This study was conducted to evaluate the usefulness of preoperative RI, postoperative RI and RI variation before and after surgery expressed as a percentage (% RI) for early AKI detection in major abdominal surgery.

Methods

This was a single-centre, prospective observational trial performed in the critical care unit of an academic hospital. Eligible patients posted for major abdominal surgery under general anaesthesia using intraperitoneal approach with at least two predefined risk factors for AKI were included in the study. Renal RI was measured preoperatively and on postoperative day zero. Statistical comparisons were performed for various parameters between the AKI and the non-AKI groups. Pre- and postoperative RI receiver operating characteristics (ROC) curves were drawn and areas under the curves computed. Positive and negative predictive values, sensitivity, specificity and positive and negative likelihood ratios were calculated.

Results

A total of 69 subjects were enrolled, of which 14 developed AKI in the postoperative period. The mean resistive indices measured were 0.65 ± 0.09 and 0.74 ± 0.09 in the pre- and postoperative periods, respectively. The area under the ROC curve in the postoperative RI was 0.732 with 95% confidence intervals of 0.592-0.871. This most accurate cut-off value to detect postoperative AKI with sensitivity 57.1% and specificity of 85.5% was 0.77.

Conclusion

Postoperative RI can detect early AKI after major abdominal surgery.

Dose-reversal effect relationship of three different doses of neostigmine in obese patients: A randomised clinical trial

Background and Aims:

Previous studies suggest that administration of vecuronium based on total body weight rather than ideal body weight (IBW) in obesity results in overdosing with prolonged recovery times. We hypothesised that larger doses of neostigmine could result in faster recovery in obese patients administered vecuronium based on total body weight.

Methods:

Forty-five obese American Society of Anesthesiologists' II patients undergoing elective surgery under general anaesthesia were randomised into 3 groups to receive neostigmine 30, 40 and 50 μg/kg. Following induction, patients were paralysed with vecuronium 0.1 mg/kg based on total body weight. Reversal was achieved with neostigmine based on the patient's group, and time to train-of-four (TOF) ratios of 0.5, 0.7 and 0.9 measured. The primary outcome variable was time to achieve TOF ratio >0.9.

Results:

Neostigmine 50 μg/kg achieved faster recovery to TOF 0.7 than neostigmine 30 and 40 μg/kg. There was no significant difference in recovery times to TOF 0.7 in patients receiving either 30 or 40 μg/kg of neostigmine. However, neostigmine 40 μg/kg attained TOF ratio 0.9 faster than 30 μg/kg. We did not note a significant difference between the 40 and 50 μg/kg dose with regard to recovery of TOF to 0.9.

Conclusion:

Facilitated recovery from neuromuscular blockade to TOF of 0.7 was faster with neostigmine 50 μg/kg compared to 40 or 30 μg/kg. Recovery to TOF ratio of 0.9 was not significantly different with 40 or 50 μg/kg doses although such time was faster as compared to 30 μg/kg dose.

Time course of psychomotor recovery after intravenous dexmedetomidine infusion as a part of balanced anaesthetic technique: A randomised, double-blind study

Background and Aims:

Dexmedetomidine is a drug that is being widely used as an adjuvant to anaesthesia because of its unique pharmacodynamic and pharmacokinetic properties. We aimed to assess the recovery of psychomotor function from balanced anaesthesia including intravenous dexmedetomidine infusion as adjunct.

Methods:

Ninety American Society of Anesthesiologists I and II patients were randomised to group D (n = 45), to receive 1 μg/kg of dexmedetomidine loading dose over 10 min, with maintenance infusion of 0.5 μg/kg/h, and group S (n = 45), to receive an equal volume of 0.9% normal saline. Objective parameters were recovery of psychomotor function assessed by Trieger dot test (TDT), digit symbol substitution test (DSST) and intraoperative opioid requirement. the total fentanyl used intraoperatively in the two groups. Statistical analysis was performed using unpaired Student's t-test, Chi-squareor Fisher's exact test.

Results:

Psychomotor recovery assessed by TDT showed statistically significant early recovery in group D compared with group S. This was seen in the maximum distance of dots missed at 30 min, 60 min, 90 min and 120 min as well as in the average distance of dots missed at identical time points. Similarly, DSST revealed early recovery at 30 min (12.4 ± 5.3 vs. 10.4 ± 3.9 P = 0.04) postoperative interval but not at other time intervals. There was significant decrease in the intraoperative opioid requirement in group D compared with group S.

Conclusion:

The addition of dexmedetomidine to balanced anaesthetic technique significantly hastened the psychomotor recovery compared with placebo.

Spinal anesthetic for emergency cesarean section in a parturient with uncorrected tetralogy of Fallot, presenting with abruptio placentae and gestational hypertension

A subarachnoid block is an effective way of providing anesthesia for cesarean sections. However, it can be considered relatively contra-indicated in parturients with uncorrected tetralogy of Fallot (TOF). We report a case of a 22-year-old female patient with TOF and gestational hypertension, who presented for an emergency cesarean section for placental abruption. The surgery was successfully conducted under a spinal anesthetic with a combination of low dose bupivacaine and fentanyl. Fentanyl combined with small-dose bupivacaine in the subarachnoid space can be considered as an alternative technique to general anesthesia, in selected parturients with uncorrected TOF presenting for cesarean section, especially in cases where the risks of administering a general anesthetic are deemed high.

Study of glutathione S-transferase levels in patients receiving intravenous paracetamol perioperatively: A randomized controlled trial

BACKGROUND AND AIMS

Many studies have analyzed the effect of paracetamol on liver functions. The aim of this study was to measure glutathione S-transferase (GST) concentrations in patients receiving intravenous (IV) paracetamol infusions as part of their perioperative pain relief regimen to assess its effect on hepatocellular integrity.

METHODS

Patients between the ages of 18 and 60 years of both sexes, of American Society of Anesthesiologists (ASA) grades 1 and 2, undergoing laparoscopic gastrointestinal (GI) surgeries were included in the study. Patients in the saline group received three doses of normal saline as placebo 8 h apart, with the first dose administered following the induction of anesthesia. Patients in the paracetamol group received IV paracetamol at identical time points. Blood samples were collected preoperatively, after 1, 6, and at 24 h after induction. GST levels were measured at baseline and after 1, 6, and 24 h in both the groups.

RESULTS

There was no statistical difference in the demographic variables between the groups. The duration and type of surgery were identical between both the groups. GST values were found to be significantly elevated both within groups, as compared to baseline, and also in the group receiving IV paracetamol as compared to the saline group. Significant elevations of liver enzymes and decrease in serum albumin levels were also noted both within and between the groups at 24 h postoperatively, as compared to the baseline values.

CONCLUSION

Intravenous paracetamol infusion during laparoscopic GI surgeries can lead to demonstrable, although subclinical impairment of hepatic function as evident by the rise in levels of GST and hepatic enzymes. Most of such subclinical injury did not progress to clinical hepatic impairment in otherwise healthy patients, as demonstrated by the fact that none of our patients manifested drug-induced hepatitis clinically. ᅟ ᅟ.

Are Congenital Arteriovenous Malformations of Proximal Upper Extremity, More on the Right: Case Report and Literature Review

This is a case of a 9-year-old boy with a congenital arteriovenous malformation (AVM) of the right upper extremity arising from the right subclavian artery. He underwent open surgical excision of the vascular tumor. Upon reviewing the literature, a high incidence of right-sided congenital AVM of the proximal upper extremity was identified. It has been suggested that this high incidence may be related to the complexity of the embryologic development of the right subclavian artery.

Combined nephrectomy and aortic valve replacement: perioperative decision-making

Open heart surgery and urologic surgery may be required for patients with coincident diseases. We report a patient who suffered from aortic valve stenosis which was asymptomatic barring atrial fibrillation. He was prescribed warfarin and then developed a large perinephric hematoma. The perioperative considerations focused on whether to conduct aortic valve replacement for this patient and, if such surgery was indicated, the appropriate time to conduct it. Traditionally, severe cardiac disease is addressed first before conducting elective noncardiac surgery; however, this option was not available since the patient already had a perinephric hematoma which could bleed more when subjected to systemic heparinization for cardiopulmonary bypass. Here, we describe the process of perioperative decision-making involving multiple specialities and re-examine several guidelines.

Effect of combinations of dexamethasone-ondansetron and dexamethasone-ondansetron-aprepitant versus aprepitant alone for early postoperative nausea and vomiting after day care gynaecological laparoscopy: A randomised clinical trial

Background and Aims:

This study was designed to compare the effectiveness of the combination of dexamethasone–ondansetron with oral aprepitant alone and triple combination therapy with all three agents (dexamethasone-ondansetron and oral aprepitant) in the prevention of postoperative nausea and vomiting (PONV) in day care gynaecologic laparoscopy.

Methods:

This was a randomised clinical trial conducted at a university teaching hospital. A total of 105 female patients were randomised into the aprepitant (A), dexamethasone-ondansetron (DO) and aprepitant-dexamethasone-ondansetron (ADO) groups. The patients in the A group received only 80 mg oral aprepitant 1 h before surgery. The patients in the DO group, received dexamethasone 8 mg at induction with ondansetron 4 mg before extubation. Patients in the ADO group received 80 mg oral aprepitant 1 h before surgery, dexamethasone 8 mg at induction and ondansetron 4 mg before extubation. Incidence of nausea and vomiting was compared between groups using the Chi-square test/Fisher's test. Bellville score for severity of PONV was analysed using the Kruskall-Wallis test. P value < 0.05 was regarded as significant.

Results:

The incidence of PONV did not show a statistically significant difference between the three groups, with a P value of 0.13 (12.5%, 30.3% and 32.3% in groups ADO, DO and A, respectively). The severity of PONV measured using Bellville score was also not significantly different among the groups [median values (IQR) of 0 (0-0), 0 (0-1), and 0 (0-1)].

Conclusion:

The combination of aprepitant, dexamethasone and ondansetron failed to demonstrate a statistically significant superiority over the other two antiemetic regimens.

Relationship between transesophageal echocardiography-derived pulmonary artery systolic pressure measurements and early morbidity in patients undergoing coronary artery bypass grafting

Context:

We studied the relationship between intraoperative transesophageal echocardiography-derived (TEE-derived) pulmonary artery systolic pressure (PASP) measurements with early morbidity in on-pump coronary artery bypass grafting (CABG) surgery.

Aims:

The objective of the study was to assess whether TEE-derived elevated PASP is independently predictive of significant morbidity.

Settings and Design:

Prospective observational study in a university hospital.

Materials and Methods:

Around 54 patients who underwent CABG under cardiopulmonary bypass (CPB) were divided into two groups; with PASP ≥35 mmHg and PASP <35 mmHg, assessed by intraoperative TEE. Outcomes studied were poor coronary revascularization, postoperative arrhythmias, myocardial infarction, respiratory failure, intra-aortic balloon pump use, pacemaker dependence, significant inotrope use, prolonged intensive care unit stay, and the total length of stay in the hospital. Mortality analysis was not a part of this study since expected sample sizes were low.

Results:

Patients with PASP ≥35 mmHg had a higher risk of respiratory failure, increased inotrope use and prolonged hospital stay, although multivariate analysis failed to demonstrate an independent association of PASP with these outcomes. Diabetes mellitus (DM), peripheral vascular disease, low cardiac output and elevated mitral annular E/e’ ratio were significantly associated with higher pulmonary arterial pressures. Multivariate analysis showed that PASP was independently associated with higher mitral annular E/e’ ratio.

Conclusions:

Our study, therefore, suggests that higher PASP may predict higher left ventricular filling pressures, and although elevated PASP ≥35 mmHg may be associated with DM; peripheral vascular disease, lower intraoperative cardiac output, postoperative respiratory failure, higher inotrope use, and delayed hospital discharge, it is not an independent predictor of any of these variables.