European Journal of Cardiovascular Medicine

Spinal anaesthesia (Central Neuraxial block) has many advantages over general anaesthesia for lower abdominal surgeries (surgeries below umbilicus).  Due to Spinal anaesthesia (sympathetic blockade) there is temporary interruption of impulse transmission in lower half of body¹. Spinal anaesthesia technique has many advantages e.g. Easy to perform, excellent muscle relaxation, patients can communicate with the surgeon, less postoperative adverse effects like reduced respiratory or cardiovascular complications, nausea and vomiting.²But in the immediate period of spinal anaesthesia, it is associated with intra-operative hemodynamic fluctuations such as hypotension, bradycardia, Total spinal anaesthesia and even unexpected cardiac arrest. The complications of spinal anaesthesia are manageable with drug therapy, hydration and monitoring of patients.^3,4,5

The haemodynamic fluctuations (e.g. blood pressure and heart rate fluctuations) under spinal anaesthesia are more in hypertensive patients than normotensive surgical patients. Hypertensive patients & patients with co-morbid conditions are more prone to develop severe/extremes of hemodynamic fluctuations, cardiac arrhythmias and even myocardial infarction⁶. In hypertensive patients, ischaemia and conduction abnormalities may manifest under spinal anaesthesia due to structural changes in arteriolar walls that leads to greater changes in systemic vascular resistance and arterial pressure⁷

This prospective & observational study was conducted in the Department of Anaesthesiology from January 2014 to October 2015, at Tertiary Care centre. Ethical committee approval was obtained from the institutional ethical committee of the institution.

A total of 60 patients between the ages 20 -70 years and belonging ASA grade I and II were studied after obtaining their written and informed consent. The participants were elective cases of Inguinal Hernia (Unilateral / bilateral) and Hydrocoele (Unilateral / bilateral) posted for surgery. We included both normotensive and hypertensive patients (irrespective of status of control of blood pressure)with or without co-morbid conditions e.g. diabetes, old myocardial infarction>6months old, ischemic heart disease etc.

Emergency surgical patients of Obstructed inguinal hernia & Pyocoele, Patients with neurological diseases (e.g. Paraplegia, hemiplegic etc), LBBB, Complete heart block, those who underwent Bypass surgery, valvular heart disease/ old myocardial infarction within 6 months were excluded from the study.

During the preanesthetic check-up (24-48 hours prior the surgery)details such as present & past history of diseases, hospitalization, preoperative blood pressure, heart rate, investigations were noted. The antihypertensive & other medications of patients were noted and instructed to continue the same (Irrespective of type of drugs used for control of hypertension & co morbid disease management) till the day of operation. Preoperative counselling of patient was done for 5 - 10 minutes in the ward (A day prior the surgery) and in the operation theatre (Patient waiting area).Investigations such as  Haemoglobin%, Complete blood count, Bleeding time & Clotting time, Blood sugar- Fasting & Post meal, Blood urea, Serum Creatinine, X- Ray Chest, ECG & relevant investigations (Pertaining to co-morbidities) were done. Tab. Diazepam- 10 mg. & Tab. Pantoprazole- 20 mg was given the previous night orally. The night before surgery “Zero hour” (00.00 am) ‘Systolic & Diastolic blood pressure’, ‘Pulse Rate’ was noted.

Written and informed consent was taken from patient or caretaker after explaining about the procedure of spinal anaesthesia, drug under study to be used, consequences of spinal anaesthesia & related intra-operative hemodynamic changes & complications. Before intravenous access and application of monitoring gadgets, the systolic blood pressure, diastolic blood pressure and pulse rate were noted in operation room. The Multipara monitor was attached & ECG changes (ischemic, extra systoles, arrhythmias etc.) if any were noted before procedure of spinal anaesthesia.

Intravenous access was established with 20 G intracatheter/ vasocath. Ringer’s lactate fluid – 500 ml was administered as preload fluid 10-15 minutes before spinal anaesthesia. Intraoperatively Dextrose & Dextrose normal saline was infused as maintenance fluid.

The position of spinal anaesthesia was explained to patient. The patient was given left or right lateral position on a horizontal table. The site of lumbar puncture (lumbar area) was cleaned with iodine, spirit and draped. Under all aseptic precautions, lumbar puncture was done with sterile 23 G (disposable) spinal needle at L3-L4 or L4-L5 inter-vertebral space. After obtaining free flow of CSF, Inj. Levo-bupivacaine 3.5ml (0.5%) was administered slowly and the time of intrathecal drug deposition (Time of Spinal anaesthesia) was noted.

After administration of spinal drug, immediately patient was made supine and then waited for 15 minutes. Later the surgeon was allowed to prepare the surgical area and to operate.

            After injection of spinal drug in to subarachnoid space (Time of spinal anaesthesia),

• Heart Rate was noted intraoperatively- every 5 minute till first 30 minute. Later on Heart rate was noted every 10 minute.
• Systolic & Diastolic Blood Pressure were noted intraoperatively every 5 min. till first 30 minute. Later the Blood pressure measurement was done every 10 minute.
• Simultaneously ECG monitor was observed for ECG changes & noted if any.
• Peri-operatively any nausea and vomiting were monitored.
• Postoperatively pulse rate, systolic blood pressure and diastolic blood pressure were noted at the end of surgery (after dressing of surgical site). The record of systolic blood pressure, diastolic blood pressure & Pulse rate were also done after 24 hrs. and 48 hrs.

POSTOPERATIVE ANALGESIA:

In the postoperative period, when patient complained of pain at surgical site Inj. Nalbuphine (0.3 mg/ kg) or Inj. Pentazocine (0.5mg/ kg) was administered intragluteal.

FOLLOW UP:

The patient’s & his relative’s mobile no. & address was noted & called for follow up, to know the postoperative outcome/ morbidity- mortality of the patient. Patient was instructed to come to hospital for review after one month (from the date of discharge). During review, ECG was done & analysed for any abnormality. Also, the follow up of patient regarding morbidity and mortality was done by telephonic enquiry after 6 months. The data of patients were analysed at the end of study period.

STATISTICAL ANALYSIS:

The continuous variables (e.g.  hemodynamic parameters) were presented as mean +/- S.D. Categorical variables were compared by performing Pearsons Chi-square test. For small numbers Fischer exact test was used wherever it is applicable. P< 0.05 was considered as statistical significance. Statistical software STATA version 13.0 was used for statistical analysis.

The mean age of patients in the present study was 48.46 ± 13.25 yrs and all participants were males. Out of 60 participants posted for surgery, 20 patients had hydrocoele and 40 patients were diagnosed for inguinal hernia.

Pre operative assessment

We found that 34 (56.7%) patients were Normotensive and 26 (43.3%) patients were Hypertensive. Heart rate variations were not noted in any participants.ECG changes were noted only among 3 (11.54%) hypertensive patients. None of the normotensive patients (34 patients) had preoperative ECG changes.There were 5 patients (19.23 %) out of 26 hypertensive patients who had associated diabetes mellitus. Three hypertensive patients (11.53 %) had history of old myocardial infarction.

Intra operative assessment

Intraoperatively,8 (30.8%) hypertensive patients and 7 (29.6%) normotensive patients developed bradycardia which was statistically insignificant.

9 (34.6%) patients among hypertensives and 4 (11.77%)patients among normotensives reported statistically significant fall in blood pressure intraoperatively.(p-value = 0.033) (Table 1)

There were no intraoperative ECG abnormalities/ changes in any of the hypertensive and normotensive patients.

Table 1. Incidence of bradycardia and hypotension among participants intra operatively

Post operative assessment

Table 2. Mean heart rate of Participants post operatively at different time points

Variations in systolic blood pressure was significant from the end of surgery to 48hrs in both hypertensive and normotensive patients. (Table 2).

In the post operative period, out of 26 hypertensive patients, 2 (7.7%) had developed headache. Only one (2.9%) normotensive patient had headache in the post operative period. Out of 34 patients, two (5.7%) normotensive patients developed urinary retention. None of the hypertensive patients developed urinary retention. The post operative outcome among hypertensives and normotensives were found to be statistically insignificant.

 Figure 1: Postoperative Complications in Hypertensive and Normotensive patients

Postoperative Outcome- follow-up at one month and six Month

No new ECG changes was noted in the participants during their visit to hospital for follow-up after date of discharge. No new abnormalities were noted.

Based on 6 months telephonic follow up, none of the patients under study developed chest pain, acute myocardial infarctionorcerebro-vascular accident. Also, no patients were hospitalized for cardiac or any other illness. There was no death of any patient under study within six months of the study.

Spinal anaesthesia is commonly employed for surgeries below the umbilicus and on the lower limbs. It is a simple, convenient, and cost-effective method that offers excellent anaesthesia and postoperative pain relief. However, it often leads to hypotension and bradycardia due to the inhibition of sympathetic nerve activity. These effects can be prevented and managed with appropriate prophylactic measures and timely interventions such as preloading, vasopressors, and inotropic drugs, which can reduce the risk of complications and improve patient outcomes.⁸

In this study, we assessed the incidence of hemodynamic changes, ECG variations and postoperative outcomes in hypertensive and normotensive patients posted for hernia and hydrocele surgeries. The mean age group of participants was 48.46 ± 13.25 years which is almost similar to a study done by Panda A et al,.⁶

Hemodynamic variations

Baseline values for heart rate, Blood pressure and ECG pattern was recorded preoperatively.The spinal anaesthetic drug used was levobupivacaine (0.5%, isobaric) for all the study participants.Continuous monitoring revealed that 30.8% (8 out of 26 patients) of hypertensive patients and 29.6% (7 out of 34 patients) of normotensive patients experienced bradycardia in the immediate intraoperative period (within 30 minutes). The mean heart rate in normotensive and hypertensive patients was found to be statistically insignificant. The bradycardia was managed with Injection Atropine- 0.6 mg I.V in titrated doses so as to achieve heart rate 60 per minute or more.

Similar study byNerminSardoganAcar et.al⁹ (2005) compared normotensive and hypertensive patients with respect to the hemodynamic effects of spinal anaesthesia performed with hyperbaric bupivacaine^[9] in 60 patients. They found that there was no significant statistical difference between the groups with respect to incidences of bradycardia and there were no significant differences in heart rate too between or within groups (p > 0.05). A prospective, randomised controlled study by Monica del-Rio-Vellosillo et.al¹⁰ (2013)usedIsobaricBupivacaine and Levobupivacainefor Knee Arthroscopy in two groups, but similar hemodynamic parameterswere found for both groups.

In our study, the incidence of bradycardia was 25%. Eleven patients had baseline heart rate between 60 - 66 beats/ minute. Moreover, 10 out of 26 hypertensive patients were on preoperative beta blockers drug therapy & lower baseline heart rates.  Similar rates were reported in other prospective studies by C. Frenkel et.al¹¹ (1992) and Randall L.Carpenteret.al¹².

The mean heart rate of hypertensive and normotensive patients at the end of surgery, after 24hrs and after 48hrs did not show statistically significant difference.A study by Topas M et al to compare the effects of hyperbaric and isobaric bupivacaine spinal anaesthesia on hemodynamic variables showed no significant differences in heart rate values between the 2 groups in all periods.¹³

The current study reported an increased incidence of hypotension in hypertensive patients when compared to normotensive patients which was statistically significant.The hypotension was managed with Injection Mephentermine-6 mg I.V. bolus (2-3 boluses) so as to maintain systolic blood pressure 80 mm/ Hg and above. In another study by Acar N S , the incidence rate of hypotension was 33% (10 out of 30 patients) in the hypertensive group and 10% (3 out of 30 patients) in the normotensive group, which were  almost similar to our results.¹⁴

We noticed a significant difference in the systolic blood pressure between hypertensive and normotensive patients both during and after surgery (up to 48 hours post-operation). However, the difference in diastolic blood pressure between these groups during the same period was not statistically significant. K S Poh et.al¹⁵ (2007) studied the preoperative blood pressure changes in normotensive and hypertensive patients ^[19] in both general and spinal anaesthesia and found that spinal anaesthesia consistently resulted in a significantly lesser change in SBP and DBP at the start of surgery. During the recovery, the average changes in hemodynamic parameters were not significantly different between hypertensive and normotensive patients.

ECG Variations

Preoperatively, three hypertensive patients (11.53 %) had history of old myocardial infarction and had preoperative ECG changes as Q wave, T inversion in II, III &aVF, Q wave, ST sagging in I, aVL and T inversion in V2 -V5.There were no intraoperative or postoperative ECG abnormalities/ changes in any of the hypertensive and normotensive patients.Yeliz Denis et al¹⁶ in 2011 studied the effect of Levobupivacaine and Bupivacaine on QT, Corrected QT (Qtc), and P Wave Dispersions in Caesarean Section in sixty parturient scheduled for elective caesarean section and found that there were no difference between two groups according to block levels, hemodynamic parameters, PWD, QTd, QTc and QTcd durations.

Postoperative Complications

Clinical studies have proved that Levobupivacaine has an equal potency as bupivacaine, but lower adverse reactions especially cardiovascular and nervous system toxicity.¹⁷

A few patients in our study experienced side effects such as head ache and urinary retention during the immediate post operative period, but none reported any adverse events for the next 6 months. A study by Rosa Herrera¹⁸et al^., compared post operative outcomes of subarachnoid anesthesia with isobaric levobupivacaine and hyperbaric bupivacaine for hip fracture surgery. They noted an increased incidence of congestive heart failure, an exacerbation of pulmonary disease, kidney disease and cardiac diseases among the group where hyperbaric bupivacaine was used and concluded that levobupivacaine was a safer choice of anaesthetics for elderly patients.

We observed that the drop in blood pressure caused by spinal anaesthesia is more pronounced in hypertensive patients compared to those with normal blood pressure. The study also indicates that levobupivacaine is a safer option for anaesthesia, with no instances of severe or prolonged adverse effects or fatalities reported within six months following surgery.

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